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The Project Gutenberg eBook of Fossil plants, Vol. 3
This eBook is for the use of anyone anywhere in the United States and most
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Title: Fossil plants, Vol. 3
A text-book for students of botany and geology
Author: A. C. Seward
Release date: May 23, 2025 [eBook #76146]
Language: English
Original publication: Cambridge: Cambridge University Press, 1917
Other information and formats: www.gutenberg.org/ebooks/76146
Credits: Peter Becker, Robert Tonsing and the Online Distributed
Proofreading Team at https://www.pgdp.net (This file was
produced from images generously made available by The Internet
Archive)
*** START OF THE PROJECT GUTENBERG EBOOK FOSSIL
PLANTS, VOL. 3 ***
This eBook is for the use of anyone anywhere in the United States and most
other parts of the world at no cost and with almost no restrictions
whatsoever. You may copy it, give it away or re-use it under the terms of
the Project Gutenberg License included with this eBook or online at
www.gutenberg.org. If you are not located in the United States, you will
have to check the laws of the country where you are located before using
this eBook.
Title: Fossil plants, Vol. 3
A text-book for students of botany and geology
Author: A. C. Seward
Release date: May 23, 2025 [eBook #76146]
Language: English
Original publication: Cambridge: Cambridge University Press, 1917
Other information and formats: www.gutenberg.org/ebooks/76146
Credits: Peter Becker, Robert Tonsing and the Online Distributed
Proofreading Team at https://www.pgdp.net (This file was
produced from images generously made available by The Internet
Archive)
*** START OF THE PROJECT GUTENBERG EBOOK FOSSIL
PLANTS, VOL. 3 ***
Page 4
CAMBRIDGE BIOLOGICAL SERIES
FOSSIL PLANTS.
FOSSIL PLANTS.
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CAMBRIDGE UNIVERSITY PRESS
C. F. CLAY, Manager
London: FETTER LANE, E.C.
Edinburgh: 100, PRINCES STREET
London: H. K. LEWIS AND CO. Ltd., 136, GOWER STREET, W.C.
London: WILLIAM WESLEY AND SON, 28, ESSEX STREET, STRAND
New York: G. P. PUTNAM’S SONS
Bombay, Calcutta and Madras: MACMILLAN AND CO., Ltd.
Toronto: J. M. DENT AND SONS, Ltd.
Tokyo: THE MARUZEN-KABUSHIKI-KAISHA
All Rights reserved
C. F. CLAY, Manager
London: FETTER LANE, E.C.
Edinburgh: 100, PRINCES STREET
London: H. K. LEWIS AND CO. Ltd., 136, GOWER STREET, W.C.
London: WILLIAM WESLEY AND SON, 28, ESSEX STREET, STRAND
New York: G. P. PUTNAM’S SONS
Bombay, Calcutta and Madras: MACMILLAN AND CO., Ltd.
Toronto: J. M. DENT AND SONS, Ltd.
Tokyo: THE MARUZEN-KABUSHIKI-KAISHA
All Rights reserved
Page 6
CHARLES RENÉ ZEILLER
Membre de l’Institut
Inspecteur général des Mines
Professeur à l’École Natle Supérieure des Mines
(1847–1915)
Membre de l’Institut
Inspecteur général des Mines
Professeur à l’École Natle Supérieure des Mines
(1847–1915)
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F OS S IL P L A N T S
A TEXT-BOOK FOR STUDENTS
OF BOTANY AND GEOLOGY
BY
A. C. SEWARD
M.A., F.RS., Hon. Sc.D. Dublin
PROFESSOR OF BOTANY IN THE UNIVERSITY;
MASTER OF DOWNING COLLEGE AND HONORARY
FELLOW OF EMMANUEL COLLEGE, CAMBRIDGE
WITH 253 ILLUSTRATIONS
VOLUME III
PTERIDOSPERMEAE, CYCADOFILICES, CORDAITALES,
CYCADOPHYTA
CAMBRIDGE:
AT THE UNIVERSITY PRESS
1917
A TEXT-BOOK FOR STUDENTS
OF BOTANY AND GEOLOGY
BY
A. C. SEWARD
M.A., F.RS., Hon. Sc.D. Dublin
PROFESSOR OF BOTANY IN THE UNIVERSITY;
MASTER OF DOWNING COLLEGE AND HONORARY
FELLOW OF EMMANUEL COLLEGE, CAMBRIDGE
WITH 253 ILLUSTRATIONS
VOLUME III
PTERIDOSPERMEAE, CYCADOFILICES, CORDAITALES,
CYCADOPHYTA
CAMBRIDGE:
AT THE UNIVERSITY PRESS
1917
Page 8
TO THE MEMORY OF MY FRIEND
CHARLES RENÉ ZEILLER
ILLUSTRIOUS AS A MAN OF SCIENCE
AND A NOBLE-HEARTED GENTLEMAN
WHOM TO KNOW WAS TO REVERE
CHARLES RENÉ ZEILLER
ILLUSTRIOUS AS A MAN OF SCIENCE
AND A NOBLE-HEARTED GENTLEMAN
WHOM TO KNOW WAS TO REVERE
Page 9
Page 10
PREFACE
IN the Preface to Volume II published in 1910 I rashly stated that it was my
intention “to devote such space as is available within the limits of a text-
book to the neglected subject of the geographical distribution of plants at
different stages in the history of the earth,” also that Volume III would be
completed with as little delay as possible. Though nearly seven years have
elapsed since the publication of the second volume it may fairly be said that
the delay is not entirely due to causes which it was in my power to control.
The subject of geographical distribution receives no connected treatment in
Volumes III and IV for the simple reason that I underestimated the space
required for the description of the Gymnosperms. The alternatives were
either to insert a greatly compressed survey of the successive floras of the
world at the end of Volume IV or to attempt a fuller and less technical
treatment of the subject in a separate book. In choosing the latter course I
am conscious that a further obligation is undertaken which it may not be
possible to fulfil; but the risk is deliberately taken. Volume IV is in the press
and will, it is hoped, be published before the end of 1917.
It is a pleasant duty to repeat my thanks to many friends who have helped
me in various ways. Dr Kidston generously and without reserve allowed me
access to his splendid collection of Palaeozoic plants, and the frequent
occurrence of his name in the list of illustrations shows how freely I have
availed myself of his kindness. He has read some of the chapters and
greatly assisted me by his friendly criticism and encouragement. By reading
the proofs of this volume Dr Scott has further increased my already large
debt to him. It is impossible to thank him adequately; he not only corrected
many careless mistakes but by wise counsel and advice he rendered me a
service which I greatly appreciate.
The exchange of views with Prof. Zeiller has been a constant source of
profit and enjoyment, and it is hard to realise that the completed book will
not receive his kindly criticism. He was a singularly unselfish and generous
colleague, always ready to help fellow workers, and he had the faculty in an
unusual degree of influencing those who had the privilege of his friendship
by his sound advice and lovable personality.
IN the Preface to Volume II published in 1910 I rashly stated that it was my
intention “to devote such space as is available within the limits of a text-
book to the neglected subject of the geographical distribution of plants at
different stages in the history of the earth,” also that Volume III would be
completed with as little delay as possible. Though nearly seven years have
elapsed since the publication of the second volume it may fairly be said that
the delay is not entirely due to causes which it was in my power to control.
The subject of geographical distribution receives no connected treatment in
Volumes III and IV for the simple reason that I underestimated the space
required for the description of the Gymnosperms. The alternatives were
either to insert a greatly compressed survey of the successive floras of the
world at the end of Volume IV or to attempt a fuller and less technical
treatment of the subject in a separate book. In choosing the latter course I
am conscious that a further obligation is undertaken which it may not be
possible to fulfil; but the risk is deliberately taken. Volume IV is in the press
and will, it is hoped, be published before the end of 1917.
It is a pleasant duty to repeat my thanks to many friends who have helped
me in various ways. Dr Kidston generously and without reserve allowed me
access to his splendid collection of Palaeozoic plants, and the frequent
occurrence of his name in the list of illustrations shows how freely I have
availed myself of his kindness. He has read some of the chapters and
greatly assisted me by his friendly criticism and encouragement. By reading
the proofs of this volume Dr Scott has further increased my already large
debt to him. It is impossible to thank him adequately; he not only corrected
many careless mistakes but by wise counsel and advice he rendered me a
service which I greatly appreciate.
The exchange of views with Prof. Zeiller has been a constant source of
profit and enjoyment, and it is hard to realise that the completed book will
not receive his kindly criticism. He was a singularly unselfish and generous
colleague, always ready to help fellow workers, and he had the faculty in an
unusual degree of influencing those who had the privilege of his friendship
by his sound advice and lovable personality.
Page 11
The death of Count Solms-Laubach has deprived Palaeobotany of one of
its most learned and strongest supporters. In common with all students of
fossil plants I owe much to the critical treatment of the subject in the
Einleitung in die Paläophytologie. Prof. Jeffrey has very kindly given me
several photographs and sections which have been of great service, and I
am similarly indebted to Prof. Zalessky. To Prof. Nathorst my thanks are
due for the great interest he has taken in my work and for his generosity in
providing drawings and showing to me many of the treasures in the famous
Stockholm Museum. Prof. Bertrand and Prof. Lignier freely supplied
photographs and drawings of specimens in their possession, and I am
particularly grateful to them for the willingness with which they always
responded to my requests.
Through the death of Prof. Lignier in March 1916 Palaeobotany has been
deprived of another original thinker who devoted himself with whole-
hearted enthusiasm to botanical research and for many years faithfully
served the University of Caen: he was a generous friend to whom one never
appealed in vain for assistance. Through the kindness of the Director of the
Indian Geological Survey I have been able to examine several fossils from
the Calcutta Museum described by Oldham and Morris and by Feistmantel.
With the Director’s permission several photographs and drawings made for
a forthcoming paper to be published by the Indian Survey are reproduced in
this volume. I take this opportunity of thanking friends in Australia who
recently afforded me facilities for examining fossil plants in their charge,
and I would especially thank Mr A. B. Walkom of the University of
Brisbane, who has recently undertaken an investigation of the rich plant-
beds in the Ipswich district, for all that he did to enable me to make the
most of a very short time available for palaeobotanical work.
For the loan of specimens and for other help I am indebted to Prof. Bayly
Balfour, Prof. Bower, Prof. Margaret Benson, Prof. Oliver, Sir David Prain,
Dr Smith Woodward, Prof. Weiss, the Director of the Geological Survey, Dr
A. H. Church, Dr Arber, and other friends. I would also acknowledge a
debt, by no means inconsiderable, to my Colleague Mr Hamshaw Thomas.
Among younger friends in the Cambridge Botany School to whom I am
indebted I wish particularly to thank Miss Ruth Holden, Miss Bancroft, Mr
Sayers, Mr Dutt and others who have rendered me willing help.
its most learned and strongest supporters. In common with all students of
fossil plants I owe much to the critical treatment of the subject in the
Einleitung in die Paläophytologie. Prof. Jeffrey has very kindly given me
several photographs and sections which have been of great service, and I
am similarly indebted to Prof. Zalessky. To Prof. Nathorst my thanks are
due for the great interest he has taken in my work and for his generosity in
providing drawings and showing to me many of the treasures in the famous
Stockholm Museum. Prof. Bertrand and Prof. Lignier freely supplied
photographs and drawings of specimens in their possession, and I am
particularly grateful to them for the willingness with which they always
responded to my requests.
Through the death of Prof. Lignier in March 1916 Palaeobotany has been
deprived of another original thinker who devoted himself with whole-
hearted enthusiasm to botanical research and for many years faithfully
served the University of Caen: he was a generous friend to whom one never
appealed in vain for assistance. Through the kindness of the Director of the
Indian Geological Survey I have been able to examine several fossils from
the Calcutta Museum described by Oldham and Morris and by Feistmantel.
With the Director’s permission several photographs and drawings made for
a forthcoming paper to be published by the Indian Survey are reproduced in
this volume. I take this opportunity of thanking friends in Australia who
recently afforded me facilities for examining fossil plants in their charge,
and I would especially thank Mr A. B. Walkom of the University of
Brisbane, who has recently undertaken an investigation of the rich plant-
beds in the Ipswich district, for all that he did to enable me to make the
most of a very short time available for palaeobotanical work.
For the loan of specimens and for other help I am indebted to Prof. Bayly
Balfour, Prof. Bower, Prof. Margaret Benson, Prof. Oliver, Sir David Prain,
Dr Smith Woodward, Prof. Weiss, the Director of the Geological Survey, Dr
A. H. Church, Dr Arber, and other friends. I would also acknowledge a
debt, by no means inconsiderable, to my Colleague Mr Hamshaw Thomas.
Among younger friends in the Cambridge Botany School to whom I am
indebted I wish particularly to thank Miss Ruth Holden, Miss Bancroft, Mr
Sayers, Mr Dutt and others who have rendered me willing help.
Page 12
In the List of Illustrations mention is made of Corporate Bodies and
individuals from whom blocks have been obtained, and I am grateful to
them for readily responding to my applications.
My Wife, though prevented by more urgent calls in the later stages of my
task from giving as much time to the illustrations as in the two former
volumes, has contributed several drawings, and my daughter Phyllis Seward
has also given me much help in preparing drawings from previously
published figures.
In spite of the vigilance and wise counsel of many friends numerous
blemishes remain and for these the author is alone responsible.
A. C. SEWARD.
Downing College Lodge,
February 10, 1917.
Note. The letters A and B added to references in the footnotes indicate that the works will be
found in the Bibliographies at the end of Volumes I and II.
individuals from whom blocks have been obtained, and I am grateful to
them for readily responding to my applications.
My Wife, though prevented by more urgent calls in the later stages of my
task from giving as much time to the illustrations as in the two former
volumes, has contributed several drawings, and my daughter Phyllis Seward
has also given me much help in preparing drawings from previously
published figures.
In spite of the vigilance and wise counsel of many friends numerous
blemishes remain and for these the author is alone responsible.
A. C. SEWARD.
Downing College Lodge,
February 10, 1917.
Note. The letters A and B added to references in the footnotes indicate that the works will be
found in the Bibliographies at the end of Volumes I and II.
Page 13
TABLE OF CONTENTS
CHAPTER XXVIII
CYCADALES (Recent). Pp. 1–34.
CHAPTER XXIX
PTERIDOSPERMEAE (continued from Volume ii.). Pp. 35–85.
PAGE
I. LYGINOPTERIDEAE 35–85
Lyginopteris 35–70
Telangium 54, 55; Lagenostoma 55–64; Lagenospermum 64–66;
Pterispermostrobus 66, 67.
Heterangium 70–85
Sphaerostoma 78–81.
CHAPTER XXX
II. MEDULLOSEAE 86–165
i. Medullosa 86–109,
156–163
Myeloxylon 106–110; Neuropteris 110–117; Alethopteris and Linopteris
113; Trigonocarpus 117–124; Codonotheca 124–126; Schützia 126–128;
Whittleseya 128–131; Dolerophyllum 132–139; Ottokaria 139–141;
Strobilites 141, 142.
ii. Colpoxylon 142–145
iii. Rhexoxylon 146–149
iv. Sutcliffia 149–156
CHAPTER XXVIII
CYCADALES (Recent). Pp. 1–34.
CHAPTER XXIX
PTERIDOSPERMEAE (continued from Volume ii.). Pp. 35–85.
PAGE
I. LYGINOPTERIDEAE 35–85
Lyginopteris 35–70
Telangium 54, 55; Lagenostoma 55–64; Lagenospermum 64–66;
Pterispermostrobus 66, 67.
Heterangium 70–85
Sphaerostoma 78–81.
CHAPTER XXX
II. MEDULLOSEAE 86–165
i. Medullosa 86–109,
156–163
Myeloxylon 106–110; Neuropteris 110–117; Alethopteris and Linopteris
113; Trigonocarpus 117–124; Codonotheca 124–126; Schützia 126–128;
Whittleseya 128–131; Dolerophyllum 132–139; Ottokaria 139–141;
Strobilites 141, 142.
ii. Colpoxylon 142–145
iii. Rhexoxylon 146–149
iv. Sutcliffia 149–156
Page 14
General considerations suggested by the anatomical features of Medullosa 156–163
III. A. STELOXYLEAE 163–165
Steloxylon 163–165
CHAPTER XXXI
PTERIDOSPERMEAE. (Foliage and seeds.) Pp. 166–174.
Pecopteris Pluckeneti 166–168; Eremopteris artemisaefolia 169–172; Wardia
172, 173; Adiantites bellidulus and Lagenospermum Arberi 173, 174.
CHAPTER XXXII
CYCADOFILICES. Pp. 175–213.
I. MEGALOXYLEAE 175–180
Megaloxylon 175–180
II. RHETINANGIEAE 181–183
Rhetinangium 181–183
III. STENOMYELEAE 183–185
Stenomyelon 183–185
IV. CYCADOXYLEAE 185–190
Cycadoxylon 185–187
Ptychoxylon 187–190
V. CALAMOPITYEAE 190–200
Calamopitys 190–196
Kalymma 194–196
Eristophyton 197–200
VI. CLADOXYLEAE 200–210
Cladoxylon 201–207
Völkelia 208–210
VII. PROTOPITYEAE 210–213
Protopitys 210–213
III. A. STELOXYLEAE 163–165
Steloxylon 163–165
CHAPTER XXXI
PTERIDOSPERMEAE. (Foliage and seeds.) Pp. 166–174.
Pecopteris Pluckeneti 166–168; Eremopteris artemisaefolia 169–172; Wardia
172, 173; Adiantites bellidulus and Lagenospermum Arberi 173, 174.
CHAPTER XXXII
CYCADOFILICES. Pp. 175–213.
I. MEGALOXYLEAE 175–180
Megaloxylon 175–180
II. RHETINANGIEAE 181–183
Rhetinangium 181–183
III. STENOMYELEAE 183–185
Stenomyelon 183–185
IV. CYCADOXYLEAE 185–190
Cycadoxylon 185–187
Ptychoxylon 187–190
V. CALAMOPITYEAE 190–200
Calamopitys 190–196
Kalymma 194–196
Eristophyton 197–200
VI. CLADOXYLEAE 200–210
Cladoxylon 201–207
Völkelia 208–210
VII. PROTOPITYEAE 210–213
Protopitys 210–213
Page 15
CHAPTER XXXIII
CORDAITALES. Pp. 214–299.
A. POROXYLEAE 214–219
Poroxylon 214–219
B. CORDAITEAE 219–284
Cordaites 219–265
Noeggerathiopsis 238–243; Rhiptozamites 244, 245; Phylladoderma 244;
Euryphyllum 245; Artisia 246–248; Dadoxylon 248–260; Metacordaites
260, 261; Cordaianthus 264–270; Mesoxylon 270–275; Pelourdea 277–
281; Niponophyllum 282, 283; Titanophyllum 283, 284.
CHAPTER XXXIV
C. PITYEAE 285–299
Pitys 285–289
Archaeopitys 290
Callixylon 291–293
Coenoxylon 293, 294
Parapitys 294, 295
Mesopitys 295, 296
Antarcticoxylon 296–299
CHAPTER XXXV
PALAEOZOIC GYMNOSPERMOUS SEEDS. Pp. 300–365.
I. Lagenostomales 308–318
Physostoma 309–312; Conostoma 313–316; Sphaerostoma 316;
Lagenostoma 316; Gnetopsis 317, 318.
II. Trigonocarpales 318–332
Trigonocarpus 319–321; Tripterospermum 321; Ptychotesta 321;
Hexapterospermum 321–323; Polypterospermum 323; Pachytesta
323–326; Stephanospermum 326–329; Polylophospermum 329, 330;
CORDAITALES. Pp. 214–299.
A. POROXYLEAE 214–219
Poroxylon 214–219
B. CORDAITEAE 219–284
Cordaites 219–265
Noeggerathiopsis 238–243; Rhiptozamites 244, 245; Phylladoderma 244;
Euryphyllum 245; Artisia 246–248; Dadoxylon 248–260; Metacordaites
260, 261; Cordaianthus 264–270; Mesoxylon 270–275; Pelourdea 277–
281; Niponophyllum 282, 283; Titanophyllum 283, 284.
CHAPTER XXXIV
C. PITYEAE 285–299
Pitys 285–289
Archaeopitys 290
Callixylon 291–293
Coenoxylon 293, 294
Parapitys 294, 295
Mesopitys 295, 296
Antarcticoxylon 296–299
CHAPTER XXXV
PALAEOZOIC GYMNOSPERMOUS SEEDS. Pp. 300–365.
I. Lagenostomales 308–318
Physostoma 309–312; Conostoma 313–316; Sphaerostoma 316;
Lagenostoma 316; Gnetopsis 317, 318.
II. Trigonocarpales 318–332
Trigonocarpus 319–321; Tripterospermum 321; Ptychotesta 321;
Hexapterospermum 321–323; Polypterospermum 323; Pachytesta
323–326; Stephanospermum 326–329; Polylophospermum 329, 330;
Page 16
Codonospermum 330, 331; Aetheotesta 331, 332; Eriotesta 332;
Gaudrya 332.
III. Cardiocarpales 332–356
Cardiocarpus 338–340; Cyclospermum 340, 341; Cycadinocarpus 341;
Rhabdocarpus and Rhabdospermum 341–345; Mitrospermum 345,
346; Diplotesta 346; Leptocaryon 346, 347; Taxospermum 347;
Compsotesta 347, 348; Samaropsis 348–354; Cordaicarpus 354–356.
IV. Miscellaneous Seeds 356–365
i. Hexagonocarpus 356,357; Decagonocarpus 357; Polypterocarpus
357, 358; Rhynchogonium 358–360; Boroviczia 360; Diplopterotesta
360, 361; Musocarpus 361; Holcospermum 361–363.
ii. Malacotesta 363; Thysanotesta 364; Carpolithus 364, 365;
Microspermum 365.
CHAPTER XXXVI
CYCADOPHYTA (Fossil). Pp. 366–420.
BENNETTITALES 367–420
Cycadeoidea 367–417
Cycadella 417, 418
Amphibennettites 418
Vectia 419, 420
CHAPTER XXXVII
BENNETTITALES (continued) 421–477
Williamsonia 421–463
Wielandiella 463–467
Williamsoniella 467–473
Cycadocephalus 473–475
Weltrichia 475–477
CHAPTER XXXVIII
CYCADOPHYTA. Pp. 478–506.
Gaudrya 332.
III. Cardiocarpales 332–356
Cardiocarpus 338–340; Cyclospermum 340, 341; Cycadinocarpus 341;
Rhabdocarpus and Rhabdospermum 341–345; Mitrospermum 345,
346; Diplotesta 346; Leptocaryon 346, 347; Taxospermum 347;
Compsotesta 347, 348; Samaropsis 348–354; Cordaicarpus 354–356.
IV. Miscellaneous Seeds 356–365
i. Hexagonocarpus 356,357; Decagonocarpus 357; Polypterocarpus
357, 358; Rhynchogonium 358–360; Boroviczia 360; Diplopterotesta
360, 361; Musocarpus 361; Holcospermum 361–363.
ii. Malacotesta 363; Thysanotesta 364; Carpolithus 364, 365;
Microspermum 365.
CHAPTER XXXVI
CYCADOPHYTA (Fossil). Pp. 366–420.
BENNETTITALES 367–420
Cycadeoidea 367–417
Cycadella 417, 418
Amphibennettites 418
Vectia 419, 420
CHAPTER XXXVII
BENNETTITALES (continued) 421–477
Williamsonia 421–463
Wielandiella 463–467
Williamsoniella 467–473
Cycadocephalus 473–475
Weltrichia 475–477
CHAPTER XXXVIII
CYCADOPHYTA. Pp. 478–506.
Page 17
i. Bucklandia 480–490; Cycadeomyelon 490, 491; Colymbetes 491–494;
Cycadeolepis 494–496.
ii. Carpolithus 497–500; Cycadospadix 500, 501; Beania 502;
Zamiostrobus, Cycadeostrobus 503–505; Androstrobus 505, 506.
CHAPTER XXXIX
CYCADOPHYTA (Fronds). Pp. 507–591.
I. Bennettitales 512–566
Ptilophyllum 512–529; Zamites 529–537; Otozamites 537–545;
Dictyozamites 546–548; Pterophyllum 548–558; Cycadites and
Pseudocycas 558–566.
II. Nilssoniales 566–587
Nilssonia 566–578; Ctenis 578–583; Pseudoctenis 584–587.
III. Incertae sedis 587–591
Sphenozamites 587–589; Plagiozamites 589, 590; Cycadorachis 590,
591.
List of Works referred to in the Text (Vols. III & IV). 592–639
Index 640–656
Cycadeolepis 494–496.
ii. Carpolithus 497–500; Cycadospadix 500, 501; Beania 502;
Zamiostrobus, Cycadeostrobus 503–505; Androstrobus 505, 506.
CHAPTER XXXIX
CYCADOPHYTA (Fronds). Pp. 507–591.
I. Bennettitales 512–566
Ptilophyllum 512–529; Zamites 529–537; Otozamites 537–545;
Dictyozamites 546–548; Pterophyllum 548–558; Cycadites and
Pseudocycas 558–566.
II. Nilssoniales 566–587
Nilssonia 566–578; Ctenis 578–583; Pseudoctenis 584–587.
III. Incertae sedis 587–591
Sphenozamites 587–589; Plagiozamites 589, 590; Cycadorachis 590,
591.
List of Works referred to in the Text (Vols. III & IV). 592–639
Index 640–656
Page 18
Page 19
LIST OF ILLUSTRATIONS
Several of the illustrations are printed from blocks for which I am indebted
to learned societies or to individuals. The sources from which clichés
were obtained are mentioned within square brackets. The names of
donors of photographs or drawings are added after the descriptions of the
figures.
Frontispiece. Charles René Zeiller. From a photograph given to me by
Madame Zeiller.
FIG. PAGE
377. Cycas circinalis. A. Malins Smith 2
378. Cycas revoluta. [G. R. Wieland.] 3
379. Encephalartos horridus 3
380. Cycas circinalis. [Encyclopaedia Britannica.] 4
381. Cycas revoluta and Zamia Loddigesii 5
382. Encephalartos Ghellinckii. [Camb. Phil. Soc.] 11
383. Cycas siamensis. [Encyclopaedia Britannica.] 12
384. Cycas circinalis 13
385. Cycas Micholitzii and Zamia angustifolia 14
386. Encephalartos Altensteinii; Dioon edule. S. M.
Wadham. 15
387. Cycadean Fronds 16
388. Zamia Wallisii 17
389. Zamia integrifolia. [Camb. Univ. Press.] 18
390. Zamia Loddigesii 18
391. Bowenia spectabilis. [Encyclopaedia
Britannica.] 20
392. Cycas pectinata, C. Riuminiana, C. angulata,
Encephalartos, and Stangeria 21
393. Stangeria, Encephalartos, and Ceratozamia 22
394. Macrozamia Preissii. [Camb. Univ. Press.] 23
Several of the illustrations are printed from blocks for which I am indebted
to learned societies or to individuals. The sources from which clichés
were obtained are mentioned within square brackets. The names of
donors of photographs or drawings are added after the descriptions of the
figures.
Frontispiece. Charles René Zeiller. From a photograph given to me by
Madame Zeiller.
FIG. PAGE
377. Cycas circinalis. A. Malins Smith 2
378. Cycas revoluta. [G. R. Wieland.] 3
379. Encephalartos horridus 3
380. Cycas circinalis. [Encyclopaedia Britannica.] 4
381. Cycas revoluta and Zamia Loddigesii 5
382. Encephalartos Ghellinckii. [Camb. Phil. Soc.] 11
383. Cycas siamensis. [Encyclopaedia Britannica.] 12
384. Cycas circinalis 13
385. Cycas Micholitzii and Zamia angustifolia 14
386. Encephalartos Altensteinii; Dioon edule. S. M.
Wadham. 15
387. Cycadean Fronds 16
388. Zamia Wallisii 17
389. Zamia integrifolia. [Camb. Univ. Press.] 18
390. Zamia Loddigesii 18
391. Bowenia spectabilis. [Encyclopaedia
Britannica.] 20
392. Cycas pectinata, C. Riuminiana, C. angulata,
Encephalartos, and Stangeria 21
393. Stangeria, Encephalartos, and Ceratozamia 22
394. Macrozamia Preissii. [Camb. Univ. Press.] 23
Page 20
FIG. PAGE
395. Zamia floridana. [G. R. Wieland.] 24
396. Dioon edule, Cycas circinalis, etc.,
Encephalartos, Bowenia, Macrozamia,
Microcycas 26
397. Stangeria paradoxa. [New Phytologist; A. G.
Tansley.] 29
398. Macrozamia 29
399. Cycadean foliar bundles 31
400. Cycas Micholitzii. [Camb. Phil. Soc.] 33
401. Lyginodendron Landsburgii. R. Kidston 37
402. Lyginopteris oldhamia. [Camb. Phil Soc.] 39
403–
Lyginopteris oldhamia
405. 41, 44, 48
406. Lyginopteris oldhamia. F. W. Oliver 49
407. Crossotheca Hoeninghausi. R. Kidston and
other sources 53
408. Lagenospermum Sinclairi; Lagenostoma;
Calymmatotheca Stangeri; Crossotheca
Hoeninghausi 57
409. Lagenostoma 58
410. Lyginopteris oldhamia 69
411,
Heterangium Grievii
412. 73, 76
413. Sphenopteris elegans 78
414. Sphaerostoma ovale 79
415. Heterangium Grievii; H. tiliaeoides;
Lyginopteris root 82
416. Medullosa (stem-anatomy) 92
417. Medullosa centrofilis 96
418. Myeloxylon radiatum; Medullosa stellata; M.
Leuckarti 103
419. Medullosa Leuckarti 104
395. Zamia floridana. [G. R. Wieland.] 24
396. Dioon edule, Cycas circinalis, etc.,
Encephalartos, Bowenia, Macrozamia,
Microcycas 26
397. Stangeria paradoxa. [New Phytologist; A. G.
Tansley.] 29
398. Macrozamia 29
399. Cycadean foliar bundles 31
400. Cycas Micholitzii. [Camb. Phil. Soc.] 33
401. Lyginodendron Landsburgii. R. Kidston 37
402. Lyginopteris oldhamia. [Camb. Phil Soc.] 39
403–
Lyginopteris oldhamia
405. 41, 44, 48
406. Lyginopteris oldhamia. F. W. Oliver 49
407. Crossotheca Hoeninghausi. R. Kidston and
other sources 53
408. Lagenospermum Sinclairi; Lagenostoma;
Calymmatotheca Stangeri; Crossotheca
Hoeninghausi 57
409. Lagenostoma 58
410. Lyginopteris oldhamia 69
411,
Heterangium Grievii
412. 73, 76
413. Sphenopteris elegans 78
414. Sphaerostoma ovale 79
415. Heterangium Grievii; H. tiliaeoides;
Lyginopteris root 82
416. Medullosa (stem-anatomy) 92
417. Medullosa centrofilis 96
418. Myeloxylon radiatum; Medullosa stellata; M.
Leuckarti 103
419. Medullosa Leuckarti 104
Page 21
FIG. PAGE
420. Myeloxylon radiatum; Medullosa anglica, and
Medullosa sp. 107
421. Potoniea adiantiformis; Linopteris obliqua;
Neuropteris heterophylla 111
422. Neuropterocarpus Kidstoni. [Edinburgh Royal
Society.] 114
423–
Trigonocarpus Parkinsoni
426. 118, 120, 121
427. Codonotheca caduca. [New Phytologist.] 125
428. Whittleseya elegans; W. brevifolia 128
429. Whittleseya elegans 130
430–
Dolerophyllum Goepperti
432. 133, 134, 137
433. Ottokaria bengalensis. [Indian Geol. Survey.] 140
434. Strobilites Milleryensis 141
435,
Colpoxylon aeduense
436. 143
437,
Rhexoxylon africanum
438. 146, 148
439,
Sutcliffia insignis
440. 150, 151
441. Steloxylon Ludwigii 163
442. Pecopteris Pluckeneti 167
443. Eremopteris artemisaefolia; Samaropsis acuta 170
444. Samaropsis acuta. R. Kidston 171
445. Wardia fertilis 172
446–
Megaloxylon Scotti. [Camb. Phil. Soc.]
448. 176–178
449,
Rhetinangium Arberi. W. T. Gordon
450. 182
451. Stenomyelon tuedianum 183
452. Stenomyelon tuedianum. R. Kidston 185
420. Myeloxylon radiatum; Medullosa anglica, and
Medullosa sp. 107
421. Potoniea adiantiformis; Linopteris obliqua;
Neuropteris heterophylla 111
422. Neuropterocarpus Kidstoni. [Edinburgh Royal
Society.] 114
423–
Trigonocarpus Parkinsoni
426. 118, 120, 121
427. Codonotheca caduca. [New Phytologist.] 125
428. Whittleseya elegans; W. brevifolia 128
429. Whittleseya elegans 130
430–
Dolerophyllum Goepperti
432. 133, 134, 137
433. Ottokaria bengalensis. [Indian Geol. Survey.] 140
434. Strobilites Milleryensis 141
435,
Colpoxylon aeduense
436. 143
437,
Rhexoxylon africanum
438. 146, 148
439,
Sutcliffia insignis
440. 150, 151
441. Steloxylon Ludwigii 163
442. Pecopteris Pluckeneti 167
443. Eremopteris artemisaefolia; Samaropsis acuta 170
444. Samaropsis acuta. R. Kidston 171
445. Wardia fertilis 172
446–
Megaloxylon Scotti. [Camb. Phil. Soc.]
448. 176–178
449,
Rhetinangium Arberi. W. T. Gordon
450. 182
451. Stenomyelon tuedianum 183
452. Stenomyelon tuedianum. R. Kidston 185
Page 22
FIG. PAGE
453. Ptychoxylon Levyi; Cycadoxylon Fremyi; C.
robustum 188
454,
Calamopitys Saturni. M. Zalessky
455. 191, 192
456. Kalymma grandis 195
457. Eristophyton fasciculare 197
458. Eristophyton Beinertianum. M. Zalessky 199
459. Cladoxylon mirabile; C. dubium; C. taeniatum;
Syncardia pusilla 202
460. Cladoxylon Kidstoni; C. mirabile 206
461. Völkelia refracta 209
462. Protopitys Buchiana 211
463. Poroxylon Edwardsii. C. E. Bertrand and F. W.
Oliver 216
464. Poroxylon Edwardsii; P. Boysseti. C. E.
Bertrand 218
465. Cordaites leaf. (C. Felicis.) R. Kidston 228
466. Cordaites principalis; Artisia transversa. R.
Kidston 231
467. Cordaites lingulatus 234
468. Cordaites (Rhizo-Cordaites); Cordaites
circularis; Cordaites sp. cf. C. Lacoei; C.
crassifolius 237
469. Cordaites aequalis; C. Clerci. M. Zalessky 239
470. Cordaites (Noeggerathiopsis) Hislopi. G. R.
Wieland. 241
471. Cordaites (Noeggerathiopsis) Hislopi.
[Geological Society.] 241
472. Cordaites (Noeggerathiopsis) Hislopi. [Geol.
Surv. India.] 242
473. Cordaites stem 246
474,
Dadoxylon materiarum
475. 257
453. Ptychoxylon Levyi; Cycadoxylon Fremyi; C.
robustum 188
454,
Calamopitys Saturni. M. Zalessky
455. 191, 192
456. Kalymma grandis 195
457. Eristophyton fasciculare 197
458. Eristophyton Beinertianum. M. Zalessky 199
459. Cladoxylon mirabile; C. dubium; C. taeniatum;
Syncardia pusilla 202
460. Cladoxylon Kidstoni; C. mirabile 206
461. Völkelia refracta 209
462. Protopitys Buchiana 211
463. Poroxylon Edwardsii. C. E. Bertrand and F. W.
Oliver 216
464. Poroxylon Edwardsii; P. Boysseti. C. E.
Bertrand 218
465. Cordaites leaf. (C. Felicis.) R. Kidston 228
466. Cordaites principalis; Artisia transversa. R.
Kidston 231
467. Cordaites lingulatus 234
468. Cordaites (Rhizo-Cordaites); Cordaites
circularis; Cordaites sp. cf. C. Lacoei; C.
crassifolius 237
469. Cordaites aequalis; C. Clerci. M. Zalessky 239
470. Cordaites (Noeggerathiopsis) Hislopi. G. R.
Wieland. 241
471. Cordaites (Noeggerathiopsis) Hislopi.
[Geological Society.] 241
472. Cordaites (Noeggerathiopsis) Hislopi. [Geol.
Surv. India.] 242
473. Cordaites stem 246
474,
Dadoxylon materiarum
475. 257
Page 23
FIG. PAGE
476. Dadoxylon Pedroi 259
477. Cordaites root 262
478. Cordaites? root. T. N. Leslie 263
479. Cordaianthus. F. E. Weiss 265
480. Cordaianthus Pitcairniae; C. Volkmanni 266
481. Cordaianthus Grand’Euryi; C. Williamsoni; C.
Zeilleri. C. E. Bertrand 268
482. Cordaianthus microsporangia 270
483. Mesoxylon Sutcliffii 272
484. Pelourdea vogesiaca. [Geologists’ Assoc.] 279
485. Titanophyllum Grand’Euryi 284
486,
Pitys antiqua
487. 286, 287
488. Pitys primaeva 288
489. Callixylon Trifilievi. M. Zalessky 292
490. Mesopitys Tchihatcheffi 296
491. Antarcticoxylon Priestleyi 298
492. Diagram of a synthetic type of seed 303
493. Lagenostoma ovoides; L. Lomaxi; Physostoma
elegans; Telangium Scotti; Stephanospermum
akenioides 311
494. Stephanospermum akenioides; Conostoma
oblonga; Gnetopsis elliptica; Physostoma
elegans; Mitrospermum compressum 314
495. Polypterospermum Renaultii; Ptychotesta
tenuis; Polylophospermum stephanense;
Hexapterospermum stenopterum; Diplotesta
avellana; D. Grand’Euryana; Taxospermum
Grüneri 322
496. Pachytesta incrassata; Polypterocarpus
anglicus 324
497. Pachytesta 325
476. Dadoxylon Pedroi 259
477. Cordaites root 262
478. Cordaites? root. T. N. Leslie 263
479. Cordaianthus. F. E. Weiss 265
480. Cordaianthus Pitcairniae; C. Volkmanni 266
481. Cordaianthus Grand’Euryi; C. Williamsoni; C.
Zeilleri. C. E. Bertrand 268
482. Cordaianthus microsporangia 270
483. Mesoxylon Sutcliffii 272
484. Pelourdea vogesiaca. [Geologists’ Assoc.] 279
485. Titanophyllum Grand’Euryi 284
486,
Pitys antiqua
487. 286, 287
488. Pitys primaeva 288
489. Callixylon Trifilievi. M. Zalessky 292
490. Mesopitys Tchihatcheffi 296
491. Antarcticoxylon Priestleyi 298
492. Diagram of a synthetic type of seed 303
493. Lagenostoma ovoides; L. Lomaxi; Physostoma
elegans; Telangium Scotti; Stephanospermum
akenioides 311
494. Stephanospermum akenioides; Conostoma
oblonga; Gnetopsis elliptica; Physostoma
elegans; Mitrospermum compressum 314
495. Polypterospermum Renaultii; Ptychotesta
tenuis; Polylophospermum stephanense;
Hexapterospermum stenopterum; Diplotesta
avellana; D. Grand’Euryana; Taxospermum
Grüneri 322
496. Pachytesta incrassata; Polypterocarpus
anglicus 324
497. Pachytesta 325
Page 24
FIG. PAGE
498. Codonospermum olivaeforme; Aetheotesta
elliptica 330
499. Samaropsis emarginata 337
500. Cardiocarpus drupaceus var. expansus 339
501. Cardiocarpus sclerotesta; Rhabdocarpus
cyclocaryon 340
502. Samaropsis fluitans; S. emarginata; S.
bicaudata; S. Seixasi; S. barcellosa; S.
Newberryi; Cordaicarpus Cordai 350
503. Samaropsis Leslii 352
504. Samaropsis Milleri. [Geol. Surv. India.] 353
505. Cordaicarpus Cordai 355
506. Holcospermum sulcatum; Codonospermum
anomalum; Diplopterotesta spitzbergensis;
Gnetopsis elliptica; Thysanotesta sagittula;
Rhynchogonium costatum; Boroviczia
Karpinskii; Hexagonocarpus Noeggerathi;
Rhabdospermum tunicatum 359
507. Cycadeoidea marylandica. [G. R. Wieland.] 373
508,
Cycadeoidea Wielandi [G. R. Wieland.]
509. 375, 376
510. Cycadeoidea sp. 377
511. Cycadeoidea Gibsoniana 377
512. Cycadeoidea ingens. [G. R. Wieland.] 378
513–
Cycadeoidea. [G. R. Wieland.]
515. 380–383
516. Cycadeoidea Dartoni 384
517–
Cycadeoidea Gibsoniana
523. 387–394
524– Cycadeoidea (Bennettites) Morierei. [O.
527. Lignier.] 397–402
528–
Cycadeoidea dacotensis. [G. R. Wieland.]
532. 404–408
498. Codonospermum olivaeforme; Aetheotesta
elliptica 330
499. Samaropsis emarginata 337
500. Cardiocarpus drupaceus var. expansus 339
501. Cardiocarpus sclerotesta; Rhabdocarpus
cyclocaryon 340
502. Samaropsis fluitans; S. emarginata; S.
bicaudata; S. Seixasi; S. barcellosa; S.
Newberryi; Cordaicarpus Cordai 350
503. Samaropsis Leslii 352
504. Samaropsis Milleri. [Geol. Surv. India.] 353
505. Cordaicarpus Cordai 355
506. Holcospermum sulcatum; Codonospermum
anomalum; Diplopterotesta spitzbergensis;
Gnetopsis elliptica; Thysanotesta sagittula;
Rhynchogonium costatum; Boroviczia
Karpinskii; Hexagonocarpus Noeggerathi;
Rhabdospermum tunicatum 359
507. Cycadeoidea marylandica. [G. R. Wieland.] 373
508,
Cycadeoidea Wielandi [G. R. Wieland.]
509. 375, 376
510. Cycadeoidea sp. 377
511. Cycadeoidea Gibsoniana 377
512. Cycadeoidea ingens. [G. R. Wieland.] 378
513–
Cycadeoidea. [G. R. Wieland.]
515. 380–383
516. Cycadeoidea Dartoni 384
517–
Cycadeoidea Gibsoniana
523. 387–394
524– Cycadeoidea (Bennettites) Morierei. [O.
527. Lignier.] 397–402
528–
Cycadeoidea dacotensis. [G. R. Wieland.]
532. 404–408
Page 25
FIG. PAGE
533. Cycadeoidea colossalis. [G. R. Wieland.] 410
534. Cycadeoidea Reichenbachiana. [A. Rothpletz.] 411
535–
Cycadeoidea gigantea. [Geological Soc.]
537. 413, 414
538. Cycadeoidea micromyela 415
539. Cycadeoidea Jenneyana (?) [G. R. Wieland.] 416
540. Vectia luccombensis. [Trustees of the British
Museum.] 419
541–
Williamsonia gigas
543. 424–427
544. Williamsonia gigas. [Yorkshire Nat. Union.] 428
545. Williamsonia gigas. A. G. Nathorst. 429
546,
Williamsonia gigas
547. 430, 431
548. Williamsonia gigas. O. Lignier. 432
549,
Williamsonia gigas. [Cambridge Phil. Soc.]
550. 435, 436
551. Williamsonia spectabilis. A. G. Nathorst. 437
552. Williamsonia spectabilis. [Geological Soc.] 438
553,
Williamsonia Leckenbyi. A. G. Nathorst.
554. 439, 440
555,
Williamsonia whitbiensis. A. G. Nathorst.
556. 441
557. Williamsonia sp. [Indian Geol. Survey.] 444
558. Williamsonia Blandfordi. [Indian Geol. Survey.] 446
559. Williamsonia Carruthersi 447
560. Williamsonia Bucklandi 449
561. Williamsonia scotica 450
562–
Williamsonia scotica. [Royal Society.]
564. 451–453
565. Williamsonia spectabilis; W. whitbiensis; W.
mexicana 459
533. Cycadeoidea colossalis. [G. R. Wieland.] 410
534. Cycadeoidea Reichenbachiana. [A. Rothpletz.] 411
535–
Cycadeoidea gigantea. [Geological Soc.]
537. 413, 414
538. Cycadeoidea micromyela 415
539. Cycadeoidea Jenneyana (?) [G. R. Wieland.] 416
540. Vectia luccombensis. [Trustees of the British
Museum.] 419
541–
Williamsonia gigas
543. 424–427
544. Williamsonia gigas. [Yorkshire Nat. Union.] 428
545. Williamsonia gigas. A. G. Nathorst. 429
546,
Williamsonia gigas
547. 430, 431
548. Williamsonia gigas. O. Lignier. 432
549,
Williamsonia gigas. [Cambridge Phil. Soc.]
550. 435, 436
551. Williamsonia spectabilis. A. G. Nathorst. 437
552. Williamsonia spectabilis. [Geological Soc.] 438
553,
Williamsonia Leckenbyi. A. G. Nathorst.
554. 439, 440
555,
Williamsonia whitbiensis. A. G. Nathorst.
556. 441
557. Williamsonia sp. [Indian Geol. Survey.] 444
558. Williamsonia Blandfordi. [Indian Geol. Survey.] 446
559. Williamsonia Carruthersi 447
560. Williamsonia Bucklandi 449
561. Williamsonia scotica 450
562–
Williamsonia scotica. [Royal Society.]
564. 451–453
565. Williamsonia spectabilis; W. whitbiensis; W.
mexicana 459
Page 26
FIG. PAGE
566,
Wielandiella angustifolia
567. 463, 464
568. Wielandiella angustifolia. A. G. Nathorst. 466
569–
Williamsoniella coronata. [Royal Society.]
573. 468–471
574. Cycadocephalus Sewardi. A. G. Nathorst. 474
575. Bucklandia anomala 482
576. Bucklandia Milleriana 484
577. Bucklandia Yatesii 485
578. Bucklandia buzzardensis. [Trustees of the
British Museum.] 486
579. Bucklandia indica. [Trustees of the British
Museum.] 488
580, Colymbetes Edwardsi [Trustees of the British
581. Museum.] 492, 493
582,
Cycadolepis sp.
583. 495
584, Carpolithus conicus [Trustees of the British
585. Museum.] 498
586. Beania gracilis. [W. G. Carruthers.] 502
587. Ptilophyllum pecten. [Trustees of the British
Museum.] 513
588,
Ptilophyllum pecten [Geological Surv. India.]
589. 514, 516
590. Ptilophyllum pecten and Williamsonia
Blandfordi [Geological Surv. India.] 517
591. Ptilophyllum cutchense. [Geological Society.] 518
592. Ptilophyllum pecten 519
593. Ptilophyllum pecten. [Geological Society.] 519
594. Ptilophyllum pecten 520
595. Ptilophyllum pecten 523
596. Ptilophyllum pecten. [Trustees of the British
Museum.] 523
566,
Wielandiella angustifolia
567. 463, 464
568. Wielandiella angustifolia. A. G. Nathorst. 466
569–
Williamsoniella coronata. [Royal Society.]
573. 468–471
574. Cycadocephalus Sewardi. A. G. Nathorst. 474
575. Bucklandia anomala 482
576. Bucklandia Milleriana 484
577. Bucklandia Yatesii 485
578. Bucklandia buzzardensis. [Trustees of the
British Museum.] 486
579. Bucklandia indica. [Trustees of the British
Museum.] 488
580, Colymbetes Edwardsi [Trustees of the British
581. Museum.] 492, 493
582,
Cycadolepis sp.
583. 495
584, Carpolithus conicus [Trustees of the British
585. Museum.] 498
586. Beania gracilis. [W. G. Carruthers.] 502
587. Ptilophyllum pecten. [Trustees of the British
Museum.] 513
588,
Ptilophyllum pecten [Geological Surv. India.]
589. 514, 516
590. Ptilophyllum pecten and Williamsonia
Blandfordi [Geological Surv. India.] 517
591. Ptilophyllum cutchense. [Geological Society.] 518
592. Ptilophyllum pecten 519
593. Ptilophyllum pecten. [Geological Society.] 519
594. Ptilophyllum pecten 520
595. Ptilophyllum pecten 523
596. Ptilophyllum pecten. [Trustees of the British
Museum.] 523
Page 27
FIG. PAGE
597. Ptilophyllum boreale. A. G. Nathorst. 526
598. Ptilophyllum antarcticum; P. Anderssoni 527
599. Zamites gigas. [Encyclopaedia Britannica.] 533
600. Zamites recta 534
601. Zamites Buchianus; Z. Carruthersi; Z. Zitteli 535
602. Zamites Buchianus 536
603. Otozamites Goeppertianus; O. Bechei 538
604. Otozamites Bechei 539
605. Otozamites Bechei 541
606. Otozamites Beani; O. Bunburyanus
[Encyclopaedia Britannica.] 542
607. Otozamites bengalensis. [Geological Surv.
India.] 542
608. Otozamites Kliptsteini. [Geological Society.] 545
609. Dictyozamites Hawelli 548
610. Pterophyllum Jaegeri 549
611. Pterophyllum Nilssoni; Nilssonia mediana 551
612. Pterophyllum Fayoli 552
613. Pterophyllum Braunianum 554
614. Pterophyllum Nathorsti; Nilssonia tenuicaulis
[Royal Society of Scotland.] 556
615. Pterophyllum Nilssoni [Trustees of the British
Museum.] 557
616. Pterophyllum Lyellianum [Trustees of the
British Museum.] 557
617. Pseudocycas insignis 562
618. Pseudocycas Saportae. [Encyclopaedia
Britannica.] 564
619. Nilssonia pterophylloides; N. brevis; N.
polymorpha 567
620. Nilssonia brevis; N. saighensis 570
597. Ptilophyllum boreale. A. G. Nathorst. 526
598. Ptilophyllum antarcticum; P. Anderssoni 527
599. Zamites gigas. [Encyclopaedia Britannica.] 533
600. Zamites recta 534
601. Zamites Buchianus; Z. Carruthersi; Z. Zitteli 535
602. Zamites Buchianus 536
603. Otozamites Goeppertianus; O. Bechei 538
604. Otozamites Bechei 539
605. Otozamites Bechei 541
606. Otozamites Beani; O. Bunburyanus
[Encyclopaedia Britannica.] 542
607. Otozamites bengalensis. [Geological Surv.
India.] 542
608. Otozamites Kliptsteini. [Geological Society.] 545
609. Dictyozamites Hawelli 548
610. Pterophyllum Jaegeri 549
611. Pterophyllum Nilssoni; Nilssonia mediana 551
612. Pterophyllum Fayoli 552
613. Pterophyllum Braunianum 554
614. Pterophyllum Nathorsti; Nilssonia tenuicaulis
[Royal Society of Scotland.] 556
615. Pterophyllum Nilssoni [Trustees of the British
Museum.] 557
616. Pterophyllum Lyellianum [Trustees of the
British Museum.] 557
617. Pseudocycas insignis 562
618. Pseudocycas Saportae. [Encyclopaedia
Britannica.] 564
619. Nilssonia pterophylloides; N. brevis; N.
polymorpha 567
620. Nilssonia brevis; N. saighensis 570
Page 28
FIG. PAGE
621. Nilssonia rajmahalensis. [Geological Surv.
India.] 571
622. Nilssonia compta. [Trustees of the British
Museum.] 574
623. Nilssonia princeps. [Geological Surv. India.] 577
624,
Ctenis sp. [Manchester Phil. Lit. Society.]
625. 579
626. Ctenis sulcicaulis 583
627. Pseudoctenis eathiensis [Trustees of the British
Museum.] 584
628. Sphenozamites Rochei 588
629. Sphenozamites Belli. [Trustees of the British
Museum.] 588
621. Nilssonia rajmahalensis. [Geological Surv.
India.] 571
622. Nilssonia compta. [Trustees of the British
Museum.] 574
623. Nilssonia princeps. [Geological Surv. India.] 577
624,
Ctenis sp. [Manchester Phil. Lit. Society.]
625. 579
626. Ctenis sulcicaulis 583
627. Pseudoctenis eathiensis [Trustees of the British
Museum.] 584
628. Sphenozamites Rochei 588
629. Sphenozamites Belli. [Trustees of the British
Museum.] 588
Page 29
Page 30
CHAPTER XXVIII.
CYCADALES (recent).
Among the fossil genera described in the last chapter of the second
volume some were spoken of as true Ferns though most of them, it was
added, ‘may safely be regarded as plants which will ultimately be shown to
belong to some other group, in most cases that of the Pteridosperms.’ Since
this was written additional evidence has been obtained in favour of the
inclusion of certain genera in the Pteridosperms. In the case of Taeniopteris,
one of the genera already described, there is reason to believe that at least
one species is a member of the Cycadales and not a true Fern as formerly
supposed.
The Pteridosperms so far described are represented for the most part by
sterile leaves preserved as impressions, the genera founded on more
satisfactory material having been reserved for treatment in this volume. As
these genera are founded to a large extent on anatomical characters
oscillating in their essential features between recent Ferns and Cycads, it is
important that the student should be in possession of the anatomical
characteristics of both of these classes; and for this reason a general account
of recent Cycads is intercalated between the Pteridosperms already
described and those reserved for treatment in this volume.
The section of the Gymnosperms known as the Cycadales, represented by
nine recent genera and less than 100 species, is of exceptional importance
phylogenetically and demands special attention from palaeobotanical
students. Familiarity with the morphology of recent forms is essential not
only in relation to extinct cycadean plants but also to types which, though
not sufficiently close to surviving species to be included with them in one
class, exhibit features regarded by many botanists as indications of an
affinity either to true Cycads or to some generalised stock of which they are
an offshoot. The Cycads of to-day may fairly be spoken of as anachronisms,
plants appropriate to a former age but out of harmony with the present.
They are confined to tropical and sub-tropical regions in both the old and
CYCADALES (recent).
Among the fossil genera described in the last chapter of the second
volume some were spoken of as true Ferns though most of them, it was
added, ‘may safely be regarded as plants which will ultimately be shown to
belong to some other group, in most cases that of the Pteridosperms.’ Since
this was written additional evidence has been obtained in favour of the
inclusion of certain genera in the Pteridosperms. In the case of Taeniopteris,
one of the genera already described, there is reason to believe that at least
one species is a member of the Cycadales and not a true Fern as formerly
supposed.
The Pteridosperms so far described are represented for the most part by
sterile leaves preserved as impressions, the genera founded on more
satisfactory material having been reserved for treatment in this volume. As
these genera are founded to a large extent on anatomical characters
oscillating in their essential features between recent Ferns and Cycads, it is
important that the student should be in possession of the anatomical
characteristics of both of these classes; and for this reason a general account
of recent Cycads is intercalated between the Pteridosperms already
described and those reserved for treatment in this volume.
The section of the Gymnosperms known as the Cycadales, represented by
nine recent genera and less than 100 species, is of exceptional importance
phylogenetically and demands special attention from palaeobotanical
students. Familiarity with the morphology of recent forms is essential not
only in relation to extinct cycadean plants but also to types which, though
not sufficiently close to surviving species to be included with them in one
class, exhibit features regarded by many botanists as indications of an
affinity either to true Cycads or to some generalised stock of which they are
an offshoot. The Cycads of to-day may fairly be spoken of as anachronisms,
plants appropriate to a former age but out of harmony with the present.
They are confined to tropical and sub-tropical regions in both the old and
Page 31
new world. In habit many of them resemble tree-ferns, but the columnar
stem, which may live to a great age and attain a height of 20 metres, differs
from that of ferns in its gradually tapered form consequent on the presence
of one or more cambial cylinders. Though often unbranched (fig. 377)
branching of the main trunk is by no means unusual (fig. 378; fig. 381, B).
Many Cycads are geophilous and have short tuberous stems (figs. 383, 395,
1a; 396, E): the genus Zamia includes a few epiphytic forms[1]. The typical
cycadean stem is covered with persistent petiole-bases with or without an
admixture of smaller scale-leaf bases (figs. 379, 380), while in several
species a transversely wrinkled or irregularly fissured periderm forms the
superficial tissue (figs. 381, B; 383). The foliage-leaves are relatively large
and, with the exception of the bipinnate fronds of Bowenia (fig. 391), they
are always pinnate. The fronds usually form a terminal crown (figs. 377,
379) and as many as 100 may be produced from one bud. In Zamia
pygmaea[2] the fronds are only 10–12 cm. long, but in some cycads they
reach a length of several metres. On both young foliage-leaves and scale-
leaves long and very rarely branched[3] unicellular hairs (fig. 396, N) form a
characteristic feature and take the place of the ramental scales of the
majority of ferns. The apex of the stem shown in fig. 386, A is covered with
a mass of woolly hairs and several scale-leaves are seen on the lower part of
the bud.
stem, which may live to a great age and attain a height of 20 metres, differs
from that of ferns in its gradually tapered form consequent on the presence
of one or more cambial cylinders. Though often unbranched (fig. 377)
branching of the main trunk is by no means unusual (fig. 378; fig. 381, B).
Many Cycads are geophilous and have short tuberous stems (figs. 383, 395,
1a; 396, E): the genus Zamia includes a few epiphytic forms[1]. The typical
cycadean stem is covered with persistent petiole-bases with or without an
admixture of smaller scale-leaf bases (figs. 379, 380), while in several
species a transversely wrinkled or irregularly fissured periderm forms the
superficial tissue (figs. 381, B; 383). The foliage-leaves are relatively large
and, with the exception of the bipinnate fronds of Bowenia (fig. 391), they
are always pinnate. The fronds usually form a terminal crown (figs. 377,
379) and as many as 100 may be produced from one bud. In Zamia
pygmaea[2] the fronds are only 10–12 cm. long, but in some cycads they
reach a length of several metres. On both young foliage-leaves and scale-
leaves long and very rarely branched[3] unicellular hairs (fig. 396, N) form a
characteristic feature and take the place of the ramental scales of the
majority of ferns. The apex of the stem shown in fig. 386, A is covered with
a mass of woolly hairs and several scale-leaves are seen on the lower part of
the bud.
Page 32
Fig. 377. Cycas circinalis. From a photograph taken by Mr A. Malins
Smith at Teldeniya (Ceylon).
Smith at Teldeniya (Ceylon).
Page 33
Fig. 378. Cycas revoluta, as grown by Japanese horticulturalists. (After
Wieland.)
Wieland.)
Page 34
Fig. 379. Encephalartos horridus.
Fig. 380. Cycas circinalis. Stem showing alternate zones of leaf-bases
(F) and scale-leaf bases (S). (From the Encyclopaedia Britannica.)
Fig. 380. Cycas circinalis. Stem showing alternate zones of leaf-bases
(F) and scale-leaf bases (S). (From the Encyclopaedia Britannica.)
Page 35
All recent Cycads are dioecious. The reproductive shoots, except the
megasporophylls of Cycas—which have departed to a less extent than those
of other genera from the foliage-leaf plan (fig. 381, A; fig. 392, A–C) and
are borne in a terminal cluster through which the stem subsequently pushes
its way—consist of a varying number of micro- or mega-sporophylls in
dense spirals on the axis of an elongated or oval strobilus (figs. 386, B, 393,
394). The microsporophylls are occasionally verticillate[4]. The strobili are
sometimes though rarely branched[5] and generally but by no means
invariably[6] terminal on the main stem which branches sympodially[7]. A
striking example of lateral strobili has recently been described by
Chamberlain[8] who figures a stem of Macrozamia Moorei with fertile
shoots wedged among the persistent petiole-bases, a condition very similar
to that in the Mesozoic Bennettitales. Pearson has also described clear cases
of laterally-borne cones in Encephalartos. Cycas exhibits two kinds of
branching, the female plants being monopodial while in the male the
branching is sympodial. The microspores are produced in sporangia
grouped in more or less well defined sori (figs. 389, A; 392, E–G). There is
no definite annulus, but in the occurrence of groups of thick-walled cells
some microsporangia recall those of certain ferns[9]. The ovules vary
considerably in size, sometimes exceeding 5 cm. in diameter: there are
usually two on each megasporophyll (figs. 393, C; 394; 395, 1d) but in
most species of Cycas (fig. 392, B) and occasionally in other genera the
number is larger[10]. A thick integument encloses the nucellus with which it
is fused except in the apical region (fig. 396, A, B). Below the
comparatively long micropylar tube is a well-developed pollen-chamber
(fig. 396, B′, p), a striking feature of Cycadean ovules, immediately above
the megaspore; the latter is filled with prothallus-tissue and bears a small
apical group of archegonia on the floor of a depression (fig. 396, A–B′). In
Microcycas[11] as many as 200 archegonia are recorded—a very exceptional
case—and these are not confined to the apical region, though only the
apical archegonia are functional. Each archegonium is characterised by a
very large oval egg-cell and a much reduced neck[12]. The microspores
usually produce a single prothallus-cell, a stalk-cell, and body-cell, and
from the body-cell are developed two spirally ciliated spermatozoids (fig.
396, M). In this respect also the monotypic genus Microcycas is peculiar: it
may have as many as 8 body-cells and 16 male gametes in a single pollen-
tube (fig. 396, G), while in Ceratozamia[13] 4 gametes have been seen in one
megasporophylls of Cycas—which have departed to a less extent than those
of other genera from the foliage-leaf plan (fig. 381, A; fig. 392, A–C) and
are borne in a terminal cluster through which the stem subsequently pushes
its way—consist of a varying number of micro- or mega-sporophylls in
dense spirals on the axis of an elongated or oval strobilus (figs. 386, B, 393,
394). The microsporophylls are occasionally verticillate[4]. The strobili are
sometimes though rarely branched[5] and generally but by no means
invariably[6] terminal on the main stem which branches sympodially[7]. A
striking example of lateral strobili has recently been described by
Chamberlain[8] who figures a stem of Macrozamia Moorei with fertile
shoots wedged among the persistent petiole-bases, a condition very similar
to that in the Mesozoic Bennettitales. Pearson has also described clear cases
of laterally-borne cones in Encephalartos. Cycas exhibits two kinds of
branching, the female plants being monopodial while in the male the
branching is sympodial. The microspores are produced in sporangia
grouped in more or less well defined sori (figs. 389, A; 392, E–G). There is
no definite annulus, but in the occurrence of groups of thick-walled cells
some microsporangia recall those of certain ferns[9]. The ovules vary
considerably in size, sometimes exceeding 5 cm. in diameter: there are
usually two on each megasporophyll (figs. 393, C; 394; 395, 1d) but in
most species of Cycas (fig. 392, B) and occasionally in other genera the
number is larger[10]. A thick integument encloses the nucellus with which it
is fused except in the apical region (fig. 396, A, B). Below the
comparatively long micropylar tube is a well-developed pollen-chamber
(fig. 396, B′, p), a striking feature of Cycadean ovules, immediately above
the megaspore; the latter is filled with prothallus-tissue and bears a small
apical group of archegonia on the floor of a depression (fig. 396, A–B′). In
Microcycas[11] as many as 200 archegonia are recorded—a very exceptional
case—and these are not confined to the apical region, though only the
apical archegonia are functional. Each archegonium is characterised by a
very large oval egg-cell and a much reduced neck[12]. The microspores
usually produce a single prothallus-cell, a stalk-cell, and body-cell, and
from the body-cell are developed two spirally ciliated spermatozoids (fig.
396, M). In this respect also the monotypic genus Microcycas is peculiar: it
may have as many as 8 body-cells and 16 male gametes in a single pollen-
tube (fig. 396, G), while in Ceratozamia[13] 4 gametes have been seen in one
Page 36
tube. The pollen-tube grows like a fungal mycelium into the nucellar tissue
and the male gametes are formed in the distended proximal end which on
bursting liberates the motile sperms with the watery cell-sap. Fertilisation is
succeeded by the development of a homogeneous proembryo partially or
completely filling the zygote (fertilised egg): by the formation of long
suspensors the embryo is brought into contact with the food-store of the
prothallus. In some Cycads, e.g. Encephalartos, the embryogeny exhibits a
close resemblance to that of Ginkgo[14]. The embryo is dicotyledonous[15].
and the male gametes are formed in the distended proximal end which on
bursting liberates the motile sperms with the watery cell-sap. Fertilisation is
succeeded by the development of a homogeneous proembryo partially or
completely filling the zygote (fertilised egg): by the formation of long
suspensors the embryo is brought into contact with the food-store of the
prothallus. In some Cycads, e.g. Encephalartos, the embryogeny exhibits a
close resemblance to that of Ginkgo[14]. The embryo is dicotyledonous[15].
Page 37
Fig. 381. A. Cycas revoluta, megasporophylls.
B. Zamia Loddigesii, branched stem.
The single stele of the stem is characterised by a large pith which in some
genera (e.g. Encephalartos, Macrozamia) contains an anastomosing system
of collateral bundles. The vascular tissue of a cycadean stem forms a
cylinder of secondary xylem and phloem, the primary xylem being
represented only by a few, usually crushed, protoxylem elements on the
inner margin of the reticulately pitted or scalariform tracheids. Both xylem
and phloem are traversed by numerous broad and deep medullary rays[16].
B. Zamia Loddigesii, branched stem.
The single stele of the stem is characterised by a large pith which in some
genera (e.g. Encephalartos, Macrozamia) contains an anastomosing system
of collateral bundles. The vascular tissue of a cycadean stem forms a
cylinder of secondary xylem and phloem, the primary xylem being
represented only by a few, usually crushed, protoxylem elements on the
inner margin of the reticulately pitted or scalariform tracheids. Both xylem
and phloem are traversed by numerous broad and deep medullary rays[16].
Page 38
The looser texture and more parenchymatous structure of Cycadean wood
afford a ready means of distinguishing it from the wood of Conifers: for the
Cycadean type the term manoxylic is proposed and pycnoxylic for the more
compact coniferous wood[17]. Rims (or ‘bars’) of Sanio, of which much has
been said in discussions on the phylogeny of Conifers, have recently been
described in the petiolar xylem of Cycas revoluta: the rims are short and
‘cling closely to the borders of the pits,’ features which also characterise the
rims found in the cones of the Araucarineae and in the root- and cone-wood
of certain Pines[18]. In some Cycads the secondary xylem and phloem form a
single cylinder, but in others (Cycas, Encephalartos, Macrozamia,
Bowenia) the cambium is succeeded by one or several concentric cylinders
of meristem which have their origin in the pericycle. The spasmodic
occurrence of separate arcs of inversely orientated secondary xylem and
phloem between the normal cylinders is a feature of importance from the
point of view of comparison with the Palaeozoic Medulloseae[19]. The
occurrence of concentric cauline strands in the cortex of Cycas is also a
peculiarity worthy of notice. Successive bands of periderm, and
occasionally a considerable amount of phelloderm[20], are formed in the
peripheral region of the stem.
The leaf-traces in an adult stem exhibit a striking feature in their indirect
or girdle-like course to the leaves (fig. 396, H, g) and in the gradual change
from an endarch (fig. 396, O) to an apparently mesarch structure (fig. 400)
as they pass from the perimedullary zone to the petiole: except at the base
of the petiole the vascular bundles of the frond-axis consist of (i)
centripetally developed xylem with a median protoxylem and a much
smaller amount of centrifugal xylem (fig. 400) separated by a few
parenchymatous elements from the centripetal xylem, (ii) an external arc of
protophloem and within this metaphloem and parenchyma[21]. In the slender
petiole of Bowenia there are a few collateral bundles arranged in the form
of a circle or ellipse[22]; in Cycas and some other genera the more numerous
bundles form a pattern like an inverted U, and in some species of
Encephalartos the number is greater and the strands more irregularly
scattered[23]. In the vegetative stems there is no centripetal xylem in the
stele, but scattered centripetal tracheids occasionally occur internal to the
protoxylem in the steles of the peduncles[24].
Cycadeae. Megasporophylls each bearing 2–8 ovules, borne separately like foliage-leaves
and not in strobili. Pinnae have a midrib but no lateral veins (figs. 384, 387, A). Cycas (fig.
afford a ready means of distinguishing it from the wood of Conifers: for the
Cycadean type the term manoxylic is proposed and pycnoxylic for the more
compact coniferous wood[17]. Rims (or ‘bars’) of Sanio, of which much has
been said in discussions on the phylogeny of Conifers, have recently been
described in the petiolar xylem of Cycas revoluta: the rims are short and
‘cling closely to the borders of the pits,’ features which also characterise the
rims found in the cones of the Araucarineae and in the root- and cone-wood
of certain Pines[18]. In some Cycads the secondary xylem and phloem form a
single cylinder, but in others (Cycas, Encephalartos, Macrozamia,
Bowenia) the cambium is succeeded by one or several concentric cylinders
of meristem which have their origin in the pericycle. The spasmodic
occurrence of separate arcs of inversely orientated secondary xylem and
phloem between the normal cylinders is a feature of importance from the
point of view of comparison with the Palaeozoic Medulloseae[19]. The
occurrence of concentric cauline strands in the cortex of Cycas is also a
peculiarity worthy of notice. Successive bands of periderm, and
occasionally a considerable amount of phelloderm[20], are formed in the
peripheral region of the stem.
The leaf-traces in an adult stem exhibit a striking feature in their indirect
or girdle-like course to the leaves (fig. 396, H, g) and in the gradual change
from an endarch (fig. 396, O) to an apparently mesarch structure (fig. 400)
as they pass from the perimedullary zone to the petiole: except at the base
of the petiole the vascular bundles of the frond-axis consist of (i)
centripetally developed xylem with a median protoxylem and a much
smaller amount of centrifugal xylem (fig. 400) separated by a few
parenchymatous elements from the centripetal xylem, (ii) an external arc of
protophloem and within this metaphloem and parenchyma[21]. In the slender
petiole of Bowenia there are a few collateral bundles arranged in the form
of a circle or ellipse[22]; in Cycas and some other genera the more numerous
bundles form a pattern like an inverted U, and in some species of
Encephalartos the number is greater and the strands more irregularly
scattered[23]. In the vegetative stems there is no centripetal xylem in the
stele, but scattered centripetal tracheids occasionally occur internal to the
protoxylem in the steles of the peduncles[24].
Cycadeae. Megasporophylls each bearing 2–8 ovules, borne separately like foliage-leaves
and not in strobili. Pinnae have a midrib but no lateral veins (figs. 384, 387, A). Cycas (fig.
Page 39
377).
Zamieae. Both kinds of sporophylls form strobili. Pinnae have several dichotomously
branched, more or less parallel veins. Zamia (figs. 388–390), Macrozamia, Encephalartos (figs.
379, 386, C), Ceratozamia, Dioon (fig. 386, B), Microcycas.
Stangerieae. Strobili as in Zamieae. Pinnae fern-like, numerous dichotomously branched
lateral veins given off from a midrib. Stangeria.
Bowenieae. Leaves bipinnate (fig. 391), strobili as in Zamieae. Bowenia.
Distribution. The most widely spread genus, Cycas, occurs in Siam,
India, the Nicobar Islands, Ceylon, Madagascar, and Australia, in many of
the islands in the Indian and Pacific oceans, in New Guinea, Borneo, New
Caledonia, New Britain, China and Japan[25]. Zamia, the most northerly
genus, extends from North Mexico and Florida through Central America
and some of the West Indian islands to Ecuador, Bolivia, Chile, and Peru.
Dioon and Ceratozamia are confined to South Mexico, and Microcycas
flourishes on the Cuban mountains. The continent of Africa possesses two
endemic genera Encephalartos and Stangeria. Encephalartos extends from
Cape Colony through Natal and Zululand to Zanzibar and Mombasa[26]: a
specimen in the Kew Herbarium (probably E. Hildebrandti) is said to have
been collected as far north as the Soudan. Two species are recorded from
the Congo[27] and E. Barteri, discovered by Barter in Central Africa, is
recorded from the Gold Coast[28]. Stangeria has a much more limited range
in S.E. Africa[29]; Australia possesses Macrozamia, represented by several
species in Western Australia, New South Wales and Queensland, Cycas in
Queensland and the Northern territory and the Queensland genus Bowenia.
There are no Cycads in New Zealand. As a whole Cycads have a limited
range and with the exception of Cycas and Zamia none of them extend
beyond the limits of a single continent. They are as a rule not gregarious
plants and play a subordinate part in the facies of the vegetation.
Macrozamia forms dense thickets[30] in some districts and occurs both in
exposed situations and in association with Palms in damp Queensland
forests. Chamberlain[31] speaks of 100 plants of Dioon edule as visible in
one view in South Mexico where the species forms a mountain forest. In
Florida Zamia pumila[32] grows in dense moist woods, a habitat in contrast
to that of many Cycads. The Mexican Ceratozamia is associated with
luxuriant vegetation, while its compatriot Dioon[33] lives in blazing
sunshine. Sir Joseph Hooker[34] speaks of Cycas living in the deepest and
hottest valleys in Sikkim. Encephalartos is essentially a xerophilous genus.
Zamieae. Both kinds of sporophylls form strobili. Pinnae have several dichotomously
branched, more or less parallel veins. Zamia (figs. 388–390), Macrozamia, Encephalartos (figs.
379, 386, C), Ceratozamia, Dioon (fig. 386, B), Microcycas.
Stangerieae. Strobili as in Zamieae. Pinnae fern-like, numerous dichotomously branched
lateral veins given off from a midrib. Stangeria.
Bowenieae. Leaves bipinnate (fig. 391), strobili as in Zamieae. Bowenia.
Distribution. The most widely spread genus, Cycas, occurs in Siam,
India, the Nicobar Islands, Ceylon, Madagascar, and Australia, in many of
the islands in the Indian and Pacific oceans, in New Guinea, Borneo, New
Caledonia, New Britain, China and Japan[25]. Zamia, the most northerly
genus, extends from North Mexico and Florida through Central America
and some of the West Indian islands to Ecuador, Bolivia, Chile, and Peru.
Dioon and Ceratozamia are confined to South Mexico, and Microcycas
flourishes on the Cuban mountains. The continent of Africa possesses two
endemic genera Encephalartos and Stangeria. Encephalartos extends from
Cape Colony through Natal and Zululand to Zanzibar and Mombasa[26]: a
specimen in the Kew Herbarium (probably E. Hildebrandti) is said to have
been collected as far north as the Soudan. Two species are recorded from
the Congo[27] and E. Barteri, discovered by Barter in Central Africa, is
recorded from the Gold Coast[28]. Stangeria has a much more limited range
in S.E. Africa[29]; Australia possesses Macrozamia, represented by several
species in Western Australia, New South Wales and Queensland, Cycas in
Queensland and the Northern territory and the Queensland genus Bowenia.
There are no Cycads in New Zealand. As a whole Cycads have a limited
range and with the exception of Cycas and Zamia none of them extend
beyond the limits of a single continent. They are as a rule not gregarious
plants and play a subordinate part in the facies of the vegetation.
Macrozamia forms dense thickets[30] in some districts and occurs both in
exposed situations and in association with Palms in damp Queensland
forests. Chamberlain[31] speaks of 100 plants of Dioon edule as visible in
one view in South Mexico where the species forms a mountain forest. In
Florida Zamia pumila[32] grows in dense moist woods, a habitat in contrast
to that of many Cycads. The Mexican Ceratozamia is associated with
luxuriant vegetation, while its compatriot Dioon[33] lives in blazing
sunshine. Sir Joseph Hooker[34] speaks of Cycas living in the deepest and
hottest valleys in Sikkim. Encephalartos is essentially a xerophilous genus.
Page 40
Stangeria paradoxa is said to be confined to forests in Cape Colony, and
another species grows among the grass of the Park-lands in open country[35].
While it is true that many Cycads are characteristic of dry regions some
species flourish in places where shade and moisture are abundant.
Though it is impossible in many cases to form an estimate of the age of
individual plants, there are clear indications that some specimens afford
notable instances of longevity. Chamberlain estimates the age of some
plants of Dioon spinulosum as exceeding 400 years and mentions an
example of D. edule that is probably 1000 years old. An unusually tall plant
of Encephalartos in the Botanic Garden of Amsterdam is believed by Prof.
de Vries to have reached the venerable age of 2000 years[36]. The restricted
range and in many cases the solitary existence of recent Cycads, with their
tall stems clothed with the persistent cork-covered stumps of thousands of
fronds, deepens the impression of antiquity derived from a study of the
geological history of this dwindling race.
Stems. The tall columnar stems of some species of Cycas, often branched
or bearing numerous ovoid buds like enlarged bulbils[37], are characterised
by the regular alternation of large and small leaf-bases as seen in the stem
of C. circinalis reproduced in fig. 380. In older stems of this species the
leaf-bases are exfoliated and the stem is covered with wrinkled and fissured
cork; but in Cycas revoluta the leaf-bases are even more persistent. The
columnar but relatively stout stems of Encephalartos (figs. 379, 382, 386,
A) and Ceratozamia are similarly encased in a covering of petiole-bases,
but in these genera the differences between foliage-leaves and bud-scales is
much less obvious and there is no zonal alternation. On the stems of
Macrozamia the rhomboidal leaf-bases are more uniform in size and there
are no scale-leaves. The tall and often palm-like stems of Microcycas
sometimes show transverse rings on the bark marking the position of former
terminal buds, and in older trunks these may disappear, leaving a fissured
bark[38]. In Cycas siamensis the tuberous stem is similarly covered with a
rough bark (fig. 383) and the stems of Zamia are also characterised by an
absence of persistent leaf-bases (figs. 381, B; 395, Ia, a). It is pertinent to
remind the palaeobotanical student of the occurrence of flowering plants
with stems closely simulating those of some Cycads. Prof. Bower[39] in
describing Rhynchopetalum montanum, an Abyssinian Lobeliaceous plant,
drew attention to the similarity in surface-features and to some extent in
another species grows among the grass of the Park-lands in open country[35].
While it is true that many Cycads are characteristic of dry regions some
species flourish in places where shade and moisture are abundant.
Though it is impossible in many cases to form an estimate of the age of
individual plants, there are clear indications that some specimens afford
notable instances of longevity. Chamberlain estimates the age of some
plants of Dioon spinulosum as exceeding 400 years and mentions an
example of D. edule that is probably 1000 years old. An unusually tall plant
of Encephalartos in the Botanic Garden of Amsterdam is believed by Prof.
de Vries to have reached the venerable age of 2000 years[36]. The restricted
range and in many cases the solitary existence of recent Cycads, with their
tall stems clothed with the persistent cork-covered stumps of thousands of
fronds, deepens the impression of antiquity derived from a study of the
geological history of this dwindling race.
Stems. The tall columnar stems of some species of Cycas, often branched
or bearing numerous ovoid buds like enlarged bulbils[37], are characterised
by the regular alternation of large and small leaf-bases as seen in the stem
of C. circinalis reproduced in fig. 380. In older stems of this species the
leaf-bases are exfoliated and the stem is covered with wrinkled and fissured
cork; but in Cycas revoluta the leaf-bases are even more persistent. The
columnar but relatively stout stems of Encephalartos (figs. 379, 382, 386,
A) and Ceratozamia are similarly encased in a covering of petiole-bases,
but in these genera the differences between foliage-leaves and bud-scales is
much less obvious and there is no zonal alternation. On the stems of
Macrozamia the rhomboidal leaf-bases are more uniform in size and there
are no scale-leaves. The tall and often palm-like stems of Microcycas
sometimes show transverse rings on the bark marking the position of former
terminal buds, and in older trunks these may disappear, leaving a fissured
bark[38]. In Cycas siamensis the tuberous stem is similarly covered with a
rough bark (fig. 383) and the stems of Zamia are also characterised by an
absence of persistent leaf-bases (figs. 381, B; 395, Ia, a). It is pertinent to
remind the palaeobotanical student of the occurrence of flowering plants
with stems closely simulating those of some Cycads. Prof. Bower[39] in
describing Rhynchopetalum montanum, an Abyssinian Lobeliaceous plant,
drew attention to the similarity in surface-features and to some extent in
Page 41
anatomical structure to cycadean stems. The resemblances are further
emphasised in a more recently published account of the same species under
a different name, Lobelia Rhynchopetalum[40].
Fig. 382. Encephalartos Ghellinckii. (¹⁄₁₁ nat. size.)
emphasised in a more recently published account of the same species under
a different name, Lobelia Rhynchopetalum[40].
Fig. 382. Encephalartos Ghellinckii. (¹⁄₁₁ nat. size.)
Page 42
Fig. 383. Cycas siamensis. (From the Encyclopaedia Britannica.)
Fronds. A general acquaintance with the various types of fronds
illustrated by recent Cycads is important to the student of fossils not only to
enable him to compare existing and extinct forms but as affording
safeguards against possible sources of error in the description and
identification of impressions[41]. The vernation exhibits less uniformity than
in Ferns: in Cycas the rachis is straight and the pinnae circinately coiled
(fig. 220, B, vol. ii. p. 283); in Zamia and Stangeria the rachis is bent and
the pinnae straight, while in Ceratozamia and other genera both the axis and
leaflets are straight. As Braun pointed out, there is as a rule no terminal
leaflet, or it may be pushed to one side giving a forked appearance to the
frond apex[42].
Fronds. A general acquaintance with the various types of fronds
illustrated by recent Cycads is important to the student of fossils not only to
enable him to compare existing and extinct forms but as affording
safeguards against possible sources of error in the description and
identification of impressions[41]. The vernation exhibits less uniformity than
in Ferns: in Cycas the rachis is straight and the pinnae circinately coiled
(fig. 220, B, vol. ii. p. 283); in Zamia and Stangeria the rachis is bent and
the pinnae straight, while in Ceratozamia and other genera both the axis and
leaflets are straight. As Braun pointed out, there is as a rule no terminal
leaflet, or it may be pushed to one side giving a forked appearance to the
frond apex[42].
Page 43
Fig. 384. Cycas circinalis, abnormal frond. (From a specimen in the
British Museum.)
Cycas. The presence of a strong midrib and the absence of lateral veins
are distinguishing features: the lower margin of the lamina is frequently
decurrent (fig. 387, A). In C. circinalis the pinnae may reach 40 cm. in
length with a fairly uniform breadth of 2 cm. A frond of this species in the
British Museum, not quite complete, has a length of 112 cm.: on the lower
part of the rachis strong spines replace the leaflets and near the apex of the
leaf concrescent pinnae form a continuous lamina traversed by seven ribs
and dissected at the margin into acuminate teeth (fig. 384): some of the
pinnae are forked as in Cycas Micholitzii[43] (fig. 385). Several years ago I
noticed a similar instance of concrescence in a small plant of C. circinalis in
British Museum.)
Cycas. The presence of a strong midrib and the absence of lateral veins
are distinguishing features: the lower margin of the lamina is frequently
decurrent (fig. 387, A). In C. circinalis the pinnae may reach 40 cm. in
length with a fairly uniform breadth of 2 cm. A frond of this species in the
British Museum, not quite complete, has a length of 112 cm.: on the lower
part of the rachis strong spines replace the leaflets and near the apex of the
leaf concrescent pinnae form a continuous lamina traversed by seven ribs
and dissected at the margin into acuminate teeth (fig. 384): some of the
pinnae are forked as in Cycas Micholitzii[43] (fig. 385). Several years ago I
noticed a similar instance of concrescence in a small plant of C. circinalis in
Page 44
the Royal Gardens, Kew (fig. 387, I). In Cycas Micholitzii the pinnae,
reaching a length of 20 cm., are repeatedly and deeply forked (fig. 385, A,
B; fig. 400): the pinnae of C. Rumphii var. bifida[44] are also deeply
dissected. Cycas Beddomei has very narrow pinnae (15 cm. × 2 mm.)
similar to those of the Wealden species Cycadites Saportae, and it is
noteworthy that narrow leaflets with a strongly revolute lamina would
produce casts with two parallel ribs (the grooves between the midrib and
the edge of the lamina) simulating the double midrib of the fossil genus
Pseudocycas. In some fronds, e.g. C. Cairnsiana, the midrib is hardly
visible on the upper face of a dried pinna which shows a longitudinal
wrinkling simulating parallel venation.
Fig. 385. A, B, Cycas Micholitzii. (After Thiselton-Dyer.) C, Zamia
angustifolia.
reaching a length of 20 cm., are repeatedly and deeply forked (fig. 385, A,
B; fig. 400): the pinnae of C. Rumphii var. bifida[44] are also deeply
dissected. Cycas Beddomei has very narrow pinnae (15 cm. × 2 mm.)
similar to those of the Wealden species Cycadites Saportae, and it is
noteworthy that narrow leaflets with a strongly revolute lamina would
produce casts with two parallel ribs (the grooves between the midrib and
the edge of the lamina) simulating the double midrib of the fossil genus
Pseudocycas. In some fronds, e.g. C. Cairnsiana, the midrib is hardly
visible on the upper face of a dried pinna which shows a longitudinal
wrinkling simulating parallel venation.
Fig. 385. A, B, Cycas Micholitzii. (After Thiselton-Dyer.) C, Zamia
angustifolia.
Page 45
Encephalartos. The fronds of this genus, in Encephalartos
Laurentianus[45] reaching the exceptional length of 7 metres, bear alternate
pinnae exhibiting a considerable range in form and breadth. In E.
longifolius, E. Altensteinii (fig. 386, C), E. Lehmanni, etc., the pinnae are
for the most part linear, reaching a length of 20 cm. and a breadth of 2 cm.:
in E. caffer (fig. 387, D), E. latifolius, and others the pinnae are broader and
shorter and often spinous. A frond of E. longifolius or E. Altensteinii may
bear both entire and lobed, spinous pinnae. In E. Frederici-Guilielmi (fig.
387, G) and E. Ghellinckii[46] (fig. 382) the pinnae are very narrow and
almost filiform, with revolute edges. The thick and leathery pinnae of some
species are attached obliquely to the edge or to the upper sloping sides of
the rachis which forms a prominent ridge between the rows of leaflets, and
characteristic oval scars are left on the fall of the pinnae (fig. 387, D, G′).
The lamina in most species contains several veins more or less parallel to
the margins and often much more prominent on the lower than on the upper
surface.
Laurentianus[45] reaching the exceptional length of 7 metres, bear alternate
pinnae exhibiting a considerable range in form and breadth. In E.
longifolius, E. Altensteinii (fig. 386, C), E. Lehmanni, etc., the pinnae are
for the most part linear, reaching a length of 20 cm. and a breadth of 2 cm.:
in E. caffer (fig. 387, D), E. latifolius, and others the pinnae are broader and
shorter and often spinous. A frond of E. longifolius or E. Altensteinii may
bear both entire and lobed, spinous pinnae. In E. Frederici-Guilielmi (fig.
387, G) and E. Ghellinckii[46] (fig. 382) the pinnae are very narrow and
almost filiform, with revolute edges. The thick and leathery pinnae of some
species are attached obliquely to the edge or to the upper sloping sides of
the rachis which forms a prominent ridge between the rows of leaflets, and
characteristic oval scars are left on the fall of the pinnae (fig. 387, D, G′).
The lamina in most species contains several veins more or less parallel to
the margins and often much more prominent on the lower than on the upper
surface.
Page 46
Fig. 386.
A. Encephalartos Altensteinii, apex of stem.
B. Dioon edule,megastrobilus. (From a photograph by Mr S. M.
Wadham.)
C. Encephalartos Altensteinii, frond.
A. Encephalartos Altensteinii, apex of stem.
B. Dioon edule,megastrobilus. (From a photograph by Mr S. M.
Wadham.)
C. Encephalartos Altensteinii, frond.
Page 47
Fig. 387. Cycadean fronds. A, Cycas circinalis; B, Macrozamia Fraseri;
C, Macrozamia Denisoni; D, Encephalartos caffer; E, F, Dioon
edule from below and above; G, Encephalartos Frederici-Guilielmi,
G′, side-view; H, Ceratozamia mexicana; I, Cycas circinalis, lower
part of young frond.
Zamia. In Zamia angustifolia (fig. 385, C) and Z. linifolia the pinnae are
long and very narrow: the other extreme is represented by Z. Wallisii[47] (fig.
388) with broad ovate segments reaching a length of nearly ·5 metre and
attached to the rachis by a short stalk; the veins are prominent and
dichotomously branched. Other forms of pinnae are represented by Z.
C, Macrozamia Denisoni; D, Encephalartos caffer; E, F, Dioon
edule from below and above; G, Encephalartos Frederici-Guilielmi,
G′, side-view; H, Ceratozamia mexicana; I, Cycas circinalis, lower
part of young frond.
Zamia. In Zamia angustifolia (fig. 385, C) and Z. linifolia the pinnae are
long and very narrow: the other extreme is represented by Z. Wallisii[47] (fig.
388) with broad ovate segments reaching a length of nearly ·5 metre and
attached to the rachis by a short stalk; the veins are prominent and
dichotomously branched. Other forms of pinnae are represented by Z.
Page 48
integrifolia, Z. floridana, and Z. Loddigesii (figs. 389, 390, 395). The broad
and short pinnae of Z. furfuracea[48] bear a close resemblance, except in the
absence of an auriculate base, to those of some species of the fossil genus
Otozamites. The broadly linear pinnae of Z. pseudoparasitica (45 cm. × 3
cm.) often show longitudinal wrinklings on drying which suggest
comparison with the corrugated lamina of the fossil species Nilssonia
brevis. A basal pad or callosity on the slender bases of the pinnae is
characteristic of many Zamia fronds.
and short pinnae of Z. furfuracea[48] bear a close resemblance, except in the
absence of an auriculate base, to those of some species of the fossil genus
Otozamites. The broadly linear pinnae of Z. pseudoparasitica (45 cm. × 3
cm.) often show longitudinal wrinklings on drying which suggest
comparison with the corrugated lamina of the fossil species Nilssonia
brevis. A basal pad or callosity on the slender bases of the pinnae is
characteristic of many Zamia fronds.
Page 49
Fig. 388. Pinna of Zamia Wallisii. From a drawing after A. Braun in the
Kew Herbarium. (⅓ nat. size.)
Kew Herbarium. (⅓ nat. size.)
Page 50
Fig. 389. Zamia integrifolia bearing a megastrobilus and showing
foliage-leaves and scale-leaves. A, microsporophyll; B,
megasporophyll. (After Rendle, from Jacquin.)
foliage-leaves and scale-leaves. A, microsporophyll; B,
megasporophyll. (After Rendle, from Jacquin.)
Page 51
Fig. 390. Small frond of Zamia Loddigesii. (⅔ nat. size.)
Ceratozamia. The fronds bear a fairly close resemblance to those of
Macrozamia: in Ceratozamia mexicana the linear pinnae reach a length of
over 30 cm. and a breadth of 2–3 cm.; the lamina tapers to a narrow apex
and is more abruptly contracted at the base (fig. 387, H). The veins in
Ceratozamia are sub-parallel and dichotomy occurs up to the middle of the
lamina[49]. A striking feature is the occurrence of two opposite stipule-like
projections a short distance above the base of the petiole.
Macrozamia. A noteworthy feature in some species is the attachment of
the linear pinnae along the middle line of the rachis (fig. 387, C); in others
(fig. 387, B) the leaflets are attached laterally and may have a basal
callosity. The parallel veins, which branch dichotomously near the base of
the lamina, are often much more prominent on the lower than on the upper
face. In M. heteromera[50] (fig. 396, F, F′) the narrow pinnae are deeply
forked and strongly revolute. The spirally twisted rachis of M. spiralis, M.
heteromera, etc., is a striking feature recalling the Rhaetic fern
Camptopteris spiralis Nath[51].
Dioon. The arrangement of the linear pinnae of D. edule (fig. 386, B), D.
spinulosum, and D. Purpusii[52] forms a ready means of distinguishing the
Ceratozamia. The fronds bear a fairly close resemblance to those of
Macrozamia: in Ceratozamia mexicana the linear pinnae reach a length of
over 30 cm. and a breadth of 2–3 cm.; the lamina tapers to a narrow apex
and is more abruptly contracted at the base (fig. 387, H). The veins in
Ceratozamia are sub-parallel and dichotomy occurs up to the middle of the
lamina[49]. A striking feature is the occurrence of two opposite stipule-like
projections a short distance above the base of the petiole.
Macrozamia. A noteworthy feature in some species is the attachment of
the linear pinnae along the middle line of the rachis (fig. 387, C); in others
(fig. 387, B) the leaflets are attached laterally and may have a basal
callosity. The parallel veins, which branch dichotomously near the base of
the lamina, are often much more prominent on the lower than on the upper
face. In M. heteromera[50] (fig. 396, F, F′) the narrow pinnae are deeply
forked and strongly revolute. The spirally twisted rachis of M. spiralis, M.
heteromera, etc., is a striking feature recalling the Rhaetic fern
Camptopteris spiralis Nath[51].
Dioon. The arrangement of the linear pinnae of D. edule (fig. 386, B), D.
spinulosum, and D. Purpusii[52] forms a ready means of distinguishing the
Page 52
fronds of this genus: the pinnae, often contiguous and at right-angles to the
rachis, are attached in a lateral groove by an expanded and slightly
decurrent base. The difference between the lower and upper face of a frond
(fig. 387, E, F) affords a good illustration of a common source of error in
the identification of fossil specimens. The leaflets of D. spinulosum, which
except in their spinous margin are very similar to those of D. edule, may
reach a length of 15 cm. and a breadth of 8 mm. The parallel veins are
unbranched[53].
Microcycas[54]. The pinnae of this genus, very like those of the Wealden
species Zamites Buchianus, reach a length of 20 cm. and a breadth of 8
mm.: on falling they leave oblong scars resembling those on the rachis of
Encephalartos.
Stangeria. This genus is particularly interesting because of its fern-like
habit and venation. The large fronds of S. paradoxa[55] bear broadly linear
acuminate pinnae with entire, unevenly lobed, serrate, or pinnatifid
margins. Some leaflets are so deeply dissected as almost to justify the
appellation pinnate. Both entire and dissected leaflets may occur on one
frond and the lower ones may be stalked while the upper pinnae are sessile.
The venation agrees closely with that of the genus Taeniopteris[56].
Bowenia. The large fronds of this genus (fig. 391) are peculiar in being
bipinnate; they may reach a length of 2 metres and have a long slender
petiole: the asymmetrical lamina of the segments, entire or deeply serrate, is
attached by a very short stalk; the veins branch dichotomously[57] and
diverge slightly. Both entire and serrate pinnae may occur on the same
plant, but Chamberlain has revived André’s specific term serrulata in
preference to the generally adopted designation for the serrate forms, B.
spectabilis var. serrata[58].
rachis, are attached in a lateral groove by an expanded and slightly
decurrent base. The difference between the lower and upper face of a frond
(fig. 387, E, F) affords a good illustration of a common source of error in
the identification of fossil specimens. The leaflets of D. spinulosum, which
except in their spinous margin are very similar to those of D. edule, may
reach a length of 15 cm. and a breadth of 8 mm. The parallel veins are
unbranched[53].
Microcycas[54]. The pinnae of this genus, very like those of the Wealden
species Zamites Buchianus, reach a length of 20 cm. and a breadth of 8
mm.: on falling they leave oblong scars resembling those on the rachis of
Encephalartos.
Stangeria. This genus is particularly interesting because of its fern-like
habit and venation. The large fronds of S. paradoxa[55] bear broadly linear
acuminate pinnae with entire, unevenly lobed, serrate, or pinnatifid
margins. Some leaflets are so deeply dissected as almost to justify the
appellation pinnate. Both entire and dissected leaflets may occur on one
frond and the lower ones may be stalked while the upper pinnae are sessile.
The venation agrees closely with that of the genus Taeniopteris[56].
Bowenia. The large fronds of this genus (fig. 391) are peculiar in being
bipinnate; they may reach a length of 2 metres and have a long slender
petiole: the asymmetrical lamina of the segments, entire or deeply serrate, is
attached by a very short stalk; the veins branch dichotomously[57] and
diverge slightly. Both entire and serrate pinnae may occur on the same
plant, but Chamberlain has revived André’s specific term serrulata in
preference to the generally adopted designation for the serrate forms, B.
spectabilis var. serrata[58].
Page 53
Fig. 391. Bowenia spectabilis, frond. (From the Encyclopaedia
Britannica.)
Reproductive shoots[59]. In Cycas circinalis, C. Rumphii, and other species
the megasporophylls reach a considerable length and bear several lateral
ovules each of which may be as large as a goose’s egg: the sterile distal end
has the form of a spear-point with an irregularly serrate edge. In C.
revoluta, C. pectinata, etc., the sterile part is deeply dissected and may
break off (fig. 392, A) from the fertile portion of the sporophyll. The
megasporophylls of C. Riuminiana exhibit a striking variation in form (fig.
392, B, C); some are 15 cm. long with several ovules, while others, reduced
to 8 cm., bear only two ovules and resemble the sporophylls of Dioon. In all
other genera the megasporophylls are aggregated into cones, but in Dioon
the strobili are characterised by their more ovoid form and by the looser
arrangement of the sporophylls (fig. 386, B), each of which consists of a
horizontal stalk expanded distally into a broadly lanceolate upturned end
covered with a thick felt of hairs and bearing at its base usually 2, rarely 5–
Britannica.)
Reproductive shoots[59]. In Cycas circinalis, C. Rumphii, and other species
the megasporophylls reach a considerable length and bear several lateral
ovules each of which may be as large as a goose’s egg: the sterile distal end
has the form of a spear-point with an irregularly serrate edge. In C.
revoluta, C. pectinata, etc., the sterile part is deeply dissected and may
break off (fig. 392, A) from the fertile portion of the sporophyll. The
megasporophylls of C. Riuminiana exhibit a striking variation in form (fig.
392, B, C); some are 15 cm. long with several ovules, while others, reduced
to 8 cm., bear only two ovules and resemble the sporophylls of Dioon. In all
other genera the megasporophylls are aggregated into cones, but in Dioon
the strobili are characterised by their more ovoid form and by the looser
arrangement of the sporophylls (fig. 386, B), each of which consists of a
horizontal stalk expanded distally into a broadly lanceolate upturned end
covered with a thick felt of hairs and bearing at its base usually 2, rarely 5–
Page 54
6, ovules on cushion-like swellings. In Dioon spinulosum the cones may be
50 cm. long. Between the cones of Microcycas, over 90 cm. long, and those
of some Zamias, a few centimetres long, there are many intermediate forms.
The large strobilus of an Encephalartos reproduced in fig. 393, D, shows
the convex ends of the sporophylls with a jagged edge, and in monstrous
cones the marginal lobes may be abnormally developed and assume the
appearance of pinnae[60]. Each megasporophyll bears two large ovules (fig.
393, B). In certain species of Encephalartos the swollen ends of the
sporophylls have a truncate centre like the flattened umbo of some Pines
(fig. 392, D). The presence of two divergent spines is a peculiarity of the
megasporophylls of Ceratozamia (fig. 393, C): in Macrozamia (fig. 394)
the distal ends are prolonged as tapered processes. The surface of the
strobilus of Stangeria is formed by imbricate and rounded ends of
sporophylls (fig. 392, H) not unlike the cone-scales of Pinus excelsa or P.
cembra. The megasporophylls of Zamia are expanded into regular cushion-
like hexagons with a flat central area (figs. 389, B; 395, Ib).
50 cm. long. Between the cones of Microcycas, over 90 cm. long, and those
of some Zamias, a few centimetres long, there are many intermediate forms.
The large strobilus of an Encephalartos reproduced in fig. 393, D, shows
the convex ends of the sporophylls with a jagged edge, and in monstrous
cones the marginal lobes may be abnormally developed and assume the
appearance of pinnae[60]. Each megasporophyll bears two large ovules (fig.
393, B). In certain species of Encephalartos the swollen ends of the
sporophylls have a truncate centre like the flattened umbo of some Pines
(fig. 392, D). The presence of two divergent spines is a peculiarity of the
megasporophylls of Ceratozamia (fig. 393, C): in Macrozamia (fig. 394)
the distal ends are prolonged as tapered processes. The surface of the
strobilus of Stangeria is formed by imbricate and rounded ends of
sporophylls (fig. 392, H) not unlike the cone-scales of Pinus excelsa or P.
cembra. The megasporophylls of Zamia are expanded into regular cushion-
like hexagons with a flat central area (figs. 389, B; 395, Ib).
Page 55
Fig. 392.
A. Cycas pectinata, apex of megasporophyll. (¾ nat. size.)
B, C. Cycas Riuminiana, megasporophyll. (¾ nat. size.)
D. Encephalartos Altensteinii. Distal end of megasporophylls. (From the
Gardeners’ Chronicle.)
A. Cycas pectinata, apex of megasporophyll. (¾ nat. size.)
B, C. Cycas Riuminiana, megasporophyll. (¾ nat. size.)
D. Encephalartos Altensteinii. Distal end of megasporophylls. (From the
Gardeners’ Chronicle.)
Page 56
E, F. Cycas angulata, microsporophyll and sorus.
G, I. Ceratozamia mexicana, I, microsporophyll with scars of sori (s); G,
sorus. (After Thibout.)
H. Stangeria paradoxa, megastrobilus.
Fig. 393.
A. Stangeria paradoxa, part of microstrobilus.
B, D. Encephalartos villosus, megastrobilus in surface-view and in
section. (¼ nat. size.)
C. Ceratozamia mexicana, single megasporophyll.
G, I. Ceratozamia mexicana, I, microsporophyll with scars of sori (s); G,
sorus. (After Thibout.)
H. Stangeria paradoxa, megastrobilus.
Fig. 393.
A. Stangeria paradoxa, part of microstrobilus.
B, D. Encephalartos villosus, megastrobilus in surface-view and in
section. (¼ nat. size.)
C. Ceratozamia mexicana, single megasporophyll.
Page 57
Fig. 394. Macrozamia Preissii, megastrobilus and (A) single
megasporophyll; a, axis of cone; p, stalk of megasporophyll; s,
unripe seeds. (After Rendle.)
megasporophyll; a, axis of cone; p, stalk of megasporophyll; s,
unripe seeds. (After Rendle.)
Page 58
Fig. 395. Zamia floridana. Ia, complete plant; a, main trunk; b, branch-
scar; c, secondary root; d, primary tap-root. (⅛ nat. size.) Ib, Ic,
megastrobilus. (¼ nat. size.) Id, megasporophyll. (½ nat. size.) Ie,
pinna. (¾ nat. size. After Wieland.)
The microsporophylls (figs. 389, A; 392, E) are in all genera aggregated
into strobili which often bear a close resemblance to seed-cones (fig. 393,
A). On a single sporophyll of Cycas circinalis there may be as many as 700
sporangia while in Zamia floridana there are only two microsporangia. The
spore-output is large and in extreme cases, e.g. in Dioon spinulosum, the
average number of spores in a sporangium is said to be 30,000[61].
scar; c, secondary root; d, primary tap-root. (⅛ nat. size.) Ib, Ic,
megastrobilus. (¼ nat. size.) Id, megasporophyll. (½ nat. size.) Ie,
pinna. (¾ nat. size. After Wieland.)
The microsporophylls (figs. 389, A; 392, E) are in all genera aggregated
into strobili which often bear a close resemblance to seed-cones (fig. 393,
A). On a single sporophyll of Cycas circinalis there may be as many as 700
sporangia while in Zamia floridana there are only two microsporangia. The
spore-output is large and in extreme cases, e.g. in Dioon spinulosum, the
average number of spores in a sporangium is said to be 30,000[61].
Page 59
Seeds. In the great majority of recent species the seeds may be described
as large and afford a striking contrast to the small seeds of the Mesozoic
Bennettitales. A feature of interest from the point of view of comparison
with Palaeozoic seeds is the absence of a resting stage, germination in some
cases following seed-fall without an interval. As Warming pointed out, the
embryo is often undeveloped when the seeds are shed. An interesting fact is
recorded by Capt. Dorrien-Smith[62] with regard to seed-dispersal: he
describes the heavy pebble-like seeds of a Macrozamia as being hurled
from the ripe cones a distance of 12 ft. The seeds of Cycas are
platyspermic; the woody shell exposed on removal of the outer flesh is
slightly flattened and has two prominent angles, but three-angled seeds may
occur as in Ginkgo biloba (fig. 631, C). In other genera the seeds are
radiospermic. The seed of Encephalartos Altensteinii[63] (fig. 396, D) has a
square-cut distal end with a small papilla at the summit of the unusually
long micropylar canal (17 mm.). The stone of this seed (fig. 396, C) shows
parallel curved ridges which mark the position of vascular strands in the
inner region of the outer flesh. The large ovules of Cycas circinalis[64] have
an integument 1 cm. thick consisting of an outer and inner flesh and an
intervening stony layer which reaches its greatest development at the base
and apex. Three vascular strands enter the base of the seed, the concentric
strand breaks up in the broad inner flesh into a group of bundles which
embrace but do not penetrate the lower end of the nucellus. Each of the two
lateral strands branches in the outer flesh near its entrance into the seed; the
outer and larger collateral and mesarch bundle passes up close to the surface
of the shell to the seed-apex, while the inner branch penetrates the shell and,
occasionally branching, passes up the inner region of the inner flesh as far
as the micropyle. In other seeds the tracheal supply of the outer flesh
consists of several bundles and not two as in Cycas. The inner flesh abuts
on the nucellus and is connected with it except at the apex (fig. 396, B). In
ripe seeds the nucellus is reduced to a thin membrane enclosing the large
megaspore at the upper end of which is a depression (fig. 396, B′) or
sometimes two depressions (fig. 396, I) in the prothallus containing the
archegonia. In the seed of Dioon edule[65] (fig. 396, A) the position of the
absciss-layer (s) is indicated by a slight transverse constriction. In the seeds
of Bowenia, constructed on the same plan, the inner series of vascular
strands appears to be nucellar in position, thus differing from the strands in
Dioon, Cycas, and other genera which are confined to the integument. Miss
as large and afford a striking contrast to the small seeds of the Mesozoic
Bennettitales. A feature of interest from the point of view of comparison
with Palaeozoic seeds is the absence of a resting stage, germination in some
cases following seed-fall without an interval. As Warming pointed out, the
embryo is often undeveloped when the seeds are shed. An interesting fact is
recorded by Capt. Dorrien-Smith[62] with regard to seed-dispersal: he
describes the heavy pebble-like seeds of a Macrozamia as being hurled
from the ripe cones a distance of 12 ft. The seeds of Cycas are
platyspermic; the woody shell exposed on removal of the outer flesh is
slightly flattened and has two prominent angles, but three-angled seeds may
occur as in Ginkgo biloba (fig. 631, C). In other genera the seeds are
radiospermic. The seed of Encephalartos Altensteinii[63] (fig. 396, D) has a
square-cut distal end with a small papilla at the summit of the unusually
long micropylar canal (17 mm.). The stone of this seed (fig. 396, C) shows
parallel curved ridges which mark the position of vascular strands in the
inner region of the outer flesh. The large ovules of Cycas circinalis[64] have
an integument 1 cm. thick consisting of an outer and inner flesh and an
intervening stony layer which reaches its greatest development at the base
and apex. Three vascular strands enter the base of the seed, the concentric
strand breaks up in the broad inner flesh into a group of bundles which
embrace but do not penetrate the lower end of the nucellus. Each of the two
lateral strands branches in the outer flesh near its entrance into the seed; the
outer and larger collateral and mesarch bundle passes up close to the surface
of the shell to the seed-apex, while the inner branch penetrates the shell and,
occasionally branching, passes up the inner region of the inner flesh as far
as the micropyle. In other seeds the tracheal supply of the outer flesh
consists of several bundles and not two as in Cycas. The inner flesh abuts
on the nucellus and is connected with it except at the apex (fig. 396, B). In
ripe seeds the nucellus is reduced to a thin membrane enclosing the large
megaspore at the upper end of which is a depression (fig. 396, B′) or
sometimes two depressions (fig. 396, I) in the prothallus containing the
archegonia. In the seed of Dioon edule[65] (fig. 396, A) the position of the
absciss-layer (s) is indicated by a slight transverse constriction. In the seeds
of Bowenia, constructed on the same plan, the inner series of vascular
strands appears to be nucellar in position, thus differing from the strands in
Dioon, Cycas, and other genera which are confined to the integument. Miss
Page 60
Kershaw[66] in describing Bowenia speaks of an upper and a lower pollen-
chamber; the former serves as a storage-place for the microspores prior to
their further development in the lower chamber. Dr Stopes[67] regards the
integument as double in origin, a view suggested by Griffith[68] in 1835, and
as homologous with the single integument plus the cupule of Lagenostoma.
This view is supported by Mrs Thoday[69]: on the other hand Miss
Kershaw’s investigation of Bowenia seeds leads her to regard the
integument as single. Although there would seem to be a prima facie case in
favour of the dual nature of the integument, the arguments on the other side
have greater weight[70].
chamber; the former serves as a storage-place for the microspores prior to
their further development in the lower chamber. Dr Stopes[67] regards the
integument as double in origin, a view suggested by Griffith[68] in 1835, and
as homologous with the single integument plus the cupule of Lagenostoma.
This view is supported by Mrs Thoday[69]: on the other hand Miss
Kershaw’s investigation of Bowenia seeds leads her to regard the
integument as single. Although there would seem to be a prima facie case in
favour of the dual nature of the integument, the arguments on the other side
have greater weight[70].
Page 61
Fig. 396.
Page 62
A. Seed of Dioon edule in longitudinal section; a, integument; v,
vascular tissue; m, prothallus; n, nucellus; p, pollen-chamber; s,
absciss-layer; ar, archegonia. (After Chamberlain.)
B, B′. Seed of Cycas circinalis; a, v, integument (sarcotesta) and
vascular tissue; b, sclerotesta; c, inner sarcotesta; m, n, prothallus
and nucellus. (After Stopes.)
B′. Apex of nucellus; p, pollen-chamber; i, integument; n, nucellus; ch,
archegonial chamber; ar, archegonia.
C, D. Seed of Encephalartos Altensteinii; C, surface of stone. (After
Stopes.)
E. Stem of Bowenia serrulata; g, level of ground. (After Chamberlain.)
F, F′. Pinnae of Macrozamia heteromera.
G. Pollen-tube of Microcycas Calocoma. (After Caldwell.)
H. Transverse section of stem of Encephalartos horridus; s, stele; g,
girdle-bundles. (After Mettenius.)
I. Apical view of prothallus of Cycas showing two archegonial chambers
(ch). (After Treub.)
K. Encephalartos Barteri. Transverse section of stem; x, xylem; p,
phloem. (After Matte.)
L. Cycas siamensis. Transverse section of vascular tissue of young stem.
(After Matte.)
M. Cycas revoluta; two motile sperms. (After Miyake.)
N. Long hair with short basal cell from the petiole of Macrozamia
heteromera. (After Robertson.)
O. Vascular bundle of Dioon edule from base of petiole; p, phloem; c,
cambium. (After Mettenius.)
Recent observations point to the probability that insects play a part in the
pollination of cycadean ovules. Kraus[71] drew attention to the strong smell
emitted by the microstrobili of Dioon edule and noticed that small bees
were attracted to the ripe strobili of Macrozamia, while odourless cones of a
neighbouring Ceratozamia received no attention. Pearson[72] and Rattray[73]
have obtained evidence that beetles and weevils act as pollinators to species
of Encephalartos.
Anatomical features. Allusion has already been made to some of the more
striking anatomical features; the large pith, the occasional occurrence of
medullary vascular bundles, the presence of one or more cambiums, the
vascular tissue; m, prothallus; n, nucellus; p, pollen-chamber; s,
absciss-layer; ar, archegonia. (After Chamberlain.)
B, B′. Seed of Cycas circinalis; a, v, integument (sarcotesta) and
vascular tissue; b, sclerotesta; c, inner sarcotesta; m, n, prothallus
and nucellus. (After Stopes.)
B′. Apex of nucellus; p, pollen-chamber; i, integument; n, nucellus; ch,
archegonial chamber; ar, archegonia.
C, D. Seed of Encephalartos Altensteinii; C, surface of stone. (After
Stopes.)
E. Stem of Bowenia serrulata; g, level of ground. (After Chamberlain.)
F, F′. Pinnae of Macrozamia heteromera.
G. Pollen-tube of Microcycas Calocoma. (After Caldwell.)
H. Transverse section of stem of Encephalartos horridus; s, stele; g,
girdle-bundles. (After Mettenius.)
I. Apical view of prothallus of Cycas showing two archegonial chambers
(ch). (After Treub.)
K. Encephalartos Barteri. Transverse section of stem; x, xylem; p,
phloem. (After Matte.)
L. Cycas siamensis. Transverse section of vascular tissue of young stem.
(After Matte.)
M. Cycas revoluta; two motile sperms. (After Miyake.)
N. Long hair with short basal cell from the petiole of Macrozamia
heteromera. (After Robertson.)
O. Vascular bundle of Dioon edule from base of petiole; p, phloem; c,
cambium. (After Mettenius.)
Recent observations point to the probability that insects play a part in the
pollination of cycadean ovules. Kraus[71] drew attention to the strong smell
emitted by the microstrobili of Dioon edule and noticed that small bees
were attracted to the ripe strobili of Macrozamia, while odourless cones of a
neighbouring Ceratozamia received no attention. Pearson[72] and Rattray[73]
have obtained evidence that beetles and weevils act as pollinators to species
of Encephalartos.
Anatomical features. Allusion has already been made to some of the more
striking anatomical features; the large pith, the occasional occurrence of
medullary vascular bundles, the presence of one or more cambiums, the
Page 63
large size of the medullary rays, etc. It is worthy of remark that the
occurrence of an anastomosing system of medullary bundles is not a
constant feature within a genus; in Macrozamia Fraseri such a system is
present, but absent in M. Denisoni[74]. In the pith of stems with no medullary
bundles cylinders of collateral bundles may occur in connexion with a
fertile shoot. These bundles arise from the inner face of the main cylinder
and pass upwards as a domical system into the base of the terminal strobilus
which is eventually pushed to one side by the growth of a lateral bud[75]. The
secondary xylem tracheids are usually provided with several rows of
bordered pits on the radial walls and resemble those of the Araucarieae[76],
but in Cycads the pits are often not contiguous and less compact in their
distribution. The wood of Stangeria is peculiar in consisting of scalariform
tracheids[77] (fig. 397). Chamberlain describes growth-rings in the wood of
Dioon; but this is exceptional. In tangential sections of the stele leaf-trace
bundles are constantly seen passing horizontally through the broad and deep
medullary rays. The pith-cast of a cycadean stem reproduced in fig. 398
shows the wide meshes in the reticulum of tracheal tissue originally
occupied by parenchyma, which on decay left lenticular depressions
represented on the cast by tapered convex areas occasionally bearing the
impress of an outgoing trace in the form of a narrow groove. The secondary
phloem often rivals the xylem in breadth and is not always easily
distinguishable from it; it consists of sieve-tubes, parenchyma, and fibres.
The secondary cambial cylinders characteristic of Cycas, Encephalartos,
Macrozamia, and Bowenia, to which reference was made in the summary of
anatomical features, arise in the pericycle, and a few layers of pericyclic
parenchyma occur between adjacent extrafascicular cylinders of xylem and
phloem. In a stem of Cycas media 35 cm. in diameter examined by
Worsdell there were 12 concentric cylinders. Matte[78] and Miss Dorety[79]
have described partially flattened arcs of extrafascicular xylem and phloem
in the hypocotyl of Ceratozamia mexicana. Worsdell[80] first drew attention
to the occasional occurrence of short tracheids on the inner edge of the
secondary wood and to the spasmodic development of cambial arcs in the
tissue between the extrafascicular cylinders forming strands of inversely
orientated xylem and phloem. More recent work by Matte gives support to
Worsdell’s comparison between Medullosan stems and those of recent
Cycads with inversely orientated arcs or concentric vascular cylinders. The
French author draws attention to the close resemblance between the
occurrence of an anastomosing system of medullary bundles is not a
constant feature within a genus; in Macrozamia Fraseri such a system is
present, but absent in M. Denisoni[74]. In the pith of stems with no medullary
bundles cylinders of collateral bundles may occur in connexion with a
fertile shoot. These bundles arise from the inner face of the main cylinder
and pass upwards as a domical system into the base of the terminal strobilus
which is eventually pushed to one side by the growth of a lateral bud[75]. The
secondary xylem tracheids are usually provided with several rows of
bordered pits on the radial walls and resemble those of the Araucarieae[76],
but in Cycads the pits are often not contiguous and less compact in their
distribution. The wood of Stangeria is peculiar in consisting of scalariform
tracheids[77] (fig. 397). Chamberlain describes growth-rings in the wood of
Dioon; but this is exceptional. In tangential sections of the stele leaf-trace
bundles are constantly seen passing horizontally through the broad and deep
medullary rays. The pith-cast of a cycadean stem reproduced in fig. 398
shows the wide meshes in the reticulum of tracheal tissue originally
occupied by parenchyma, which on decay left lenticular depressions
represented on the cast by tapered convex areas occasionally bearing the
impress of an outgoing trace in the form of a narrow groove. The secondary
phloem often rivals the xylem in breadth and is not always easily
distinguishable from it; it consists of sieve-tubes, parenchyma, and fibres.
The secondary cambial cylinders characteristic of Cycas, Encephalartos,
Macrozamia, and Bowenia, to which reference was made in the summary of
anatomical features, arise in the pericycle, and a few layers of pericyclic
parenchyma occur between adjacent extrafascicular cylinders of xylem and
phloem. In a stem of Cycas media 35 cm. in diameter examined by
Worsdell there were 12 concentric cylinders. Matte[78] and Miss Dorety[79]
have described partially flattened arcs of extrafascicular xylem and phloem
in the hypocotyl of Ceratozamia mexicana. Worsdell[80] first drew attention
to the occasional occurrence of short tracheids on the inner edge of the
secondary wood and to the spasmodic development of cambial arcs in the
tissue between the extrafascicular cylinders forming strands of inversely
orientated xylem and phloem. More recent work by Matte gives support to
Worsdell’s comparison between Medullosan stems and those of recent
Cycads with inversely orientated arcs or concentric vascular cylinders. The
French author draws attention to the close resemblance between the
Page 64
seedling stems of such species as Encephalartos Barteri (fig. 396, K) and
Cycas siamensis (fig. 396, L) with their polystelic type of structure and the
adult stems of Medullosa[81]. In the stems of Dioon, Microcycas, Stangeria,
and Zamia no extrafascicular cylinders are recorded. Two main vascular
bundles enter the cortex from each leaf-base and in most stems these
diverge right and left and more or less completely encircle the stele before
passing through the medullary rays and joining the inner portion of the
xylem of the stele either as double or single bundles. These girdle-bundles
(fig. 396, H) first described by Karsten and Mettenius form a very
characteristic cycadean feature[82]. Adjacent girdles are joined by connecting
cortical bundles and, in addition, there are cauline collateral bundles in the
cortex which form an anastomosing system. In some cases, e.g. species of
Macrozamia and occasionally in Stangeria, the female peduncle of a
Ceratozamia, and in seedlings of Bowenia and Cycas revoluta[83], the leaf-
traces pursue a direct course from petiole to stele as in stems of
Bennettitales. It is noteworthy that in seedlings of Microcycas[84], a genus
characterised by a large number of male gametes—presumably a primitive
feature—the leaf-traces are of the girdle-type. The two bundles at the base
of a petiole by repeated subdivision give rise to the numerous collateral
strands of the rachis. A leaf-trace in its passage to the leaf is like that of a
Conifer in having the protoxylem on its inner edge, whereas in the petiole
and elsewhere in the frond it is characterised by an arrangement of the
xylem that has usually been described as mesarch. A typical vascular bundle
from a cycadean frond is seen in fig. 399, C; by far the greater part of the
xylem is centripetal, the centrifugal xylem being confined to an arc of
scattered tracheids or a small strand separated by a few parenchymatous
cells from the protoxylem.
Cycas siamensis (fig. 396, L) with their polystelic type of structure and the
adult stems of Medullosa[81]. In the stems of Dioon, Microcycas, Stangeria,
and Zamia no extrafascicular cylinders are recorded. Two main vascular
bundles enter the cortex from each leaf-base and in most stems these
diverge right and left and more or less completely encircle the stele before
passing through the medullary rays and joining the inner portion of the
xylem of the stele either as double or single bundles. These girdle-bundles
(fig. 396, H) first described by Karsten and Mettenius form a very
characteristic cycadean feature[82]. Adjacent girdles are joined by connecting
cortical bundles and, in addition, there are cauline collateral bundles in the
cortex which form an anastomosing system. In some cases, e.g. species of
Macrozamia and occasionally in Stangeria, the female peduncle of a
Ceratozamia, and in seedlings of Bowenia and Cycas revoluta[83], the leaf-
traces pursue a direct course from petiole to stele as in stems of
Bennettitales. It is noteworthy that in seedlings of Microcycas[84], a genus
characterised by a large number of male gametes—presumably a primitive
feature—the leaf-traces are of the girdle-type. The two bundles at the base
of a petiole by repeated subdivision give rise to the numerous collateral
strands of the rachis. A leaf-trace in its passage to the leaf is like that of a
Conifer in having the protoxylem on its inner edge, whereas in the petiole
and elsewhere in the frond it is characterised by an arrangement of the
xylem that has usually been described as mesarch. A typical vascular bundle
from a cycadean frond is seen in fig. 399, C; by far the greater part of the
xylem is centripetal, the centrifugal xylem being confined to an arc of
scattered tracheids or a small strand separated by a few parenchymatous
cells from the protoxylem.
Page 65
Fig. 397. Tracheids from the stem
of Stangeria paradoxa. (After Fig. 398. Pith-cast of a Macrozamia
Marsh.) stem, (⅖ nat. size.)
of Stangeria paradoxa. (After Fig. 398. Pith-cast of a Macrozamia
Marsh.) stem, (⅖ nat. size.)
Page 66
Fig. 399. Sketches illustrating the changes in the structure of Cycadean
vascular bundles in their course from stem to leaf: cp, cf,
centripetal and centrifugal xylem; p, phloem; px, protoxylem.
(After Marsh.)
As considerable stress has been laid on the anatomical features of the
cycadean foliar bundles in discussions on the affinities and phylogeny of
certain Palaeozoic genera, it is important to consider the facts more
closely[85]. French anatomists described the cycadean bundle as diploxylic
on the ground that the centripetal and centrifugal xylems are distinctly
different things, the centripetal xylem being primary—a relic of a former
organisation—and the centrifugal xylem secondary and homologous with
the normal wood of the cauline bundle. The term mesarch has in recent
years been applied to the cycadean type of bundle. A mesarch bundle is,
however, one in which centripetal and centrifugal xylem are alike in origin,
both being primary structures derived from a desmogen strand. Typical
mesarch bundles occur in several recent ferns; in the stele of the
Osmundaceae, Gleichenia, and other genera; but in these plants the xylem
is all produced directly from one primary desmogen region and there is no
question of ‘primary’ and ‘secondary’ as in the two portions of the xylem of
a cycadean bundle. Recent researches into the development of cycadean
foliar bundles show that they do not conform to the mesarch type as
vascular bundles in their course from stem to leaf: cp, cf,
centripetal and centrifugal xylem; p, phloem; px, protoxylem.
(After Marsh.)
As considerable stress has been laid on the anatomical features of the
cycadean foliar bundles in discussions on the affinities and phylogeny of
certain Palaeozoic genera, it is important to consider the facts more
closely[85]. French anatomists described the cycadean bundle as diploxylic
on the ground that the centripetal and centrifugal xylems are distinctly
different things, the centripetal xylem being primary—a relic of a former
organisation—and the centrifugal xylem secondary and homologous with
the normal wood of the cauline bundle. The term mesarch has in recent
years been applied to the cycadean type of bundle. A mesarch bundle is,
however, one in which centripetal and centrifugal xylem are alike in origin,
both being primary structures derived from a desmogen strand. Typical
mesarch bundles occur in several recent ferns; in the stele of the
Osmundaceae, Gleichenia, and other genera; but in these plants the xylem
is all produced directly from one primary desmogen region and there is no
question of ‘primary’ and ‘secondary’ as in the two portions of the xylem of
a cycadean bundle. Recent researches into the development of cycadean
foliar bundles show that they do not conform to the mesarch type as
Page 67
generally understood. A leaf-trace at the base of a petiole (fig. 399, A)
comprises centrifugal xylem only, and this consists of regular rows of
tracheids separated by medullary rays: in the lower part of the petiole the
structure is gradually modified, the centrifugal xylem is reduced and the
formation of centripetal xylem is initiated. At a higher level (fig. 399, B) the
centripetal xylem is in excess of the centrifugal and the latter, for a time
connected with the former, eventually becomes separated by a few
parenchymatous cells from the protoxylem and persists as a small strand or
arc of tracheids. Fig. 399 illustrates stages in the transformation of a typical
collateral bundle, at the base of a Stangeria petiole, into one in which the
xylem is almost wholly centripetal at a higher level in the axis of the frond.
A cambium is present in all: in B the centrifugal xylem is more or less
clearly differentiated into two portions, loosely arranged tracheids near the
phloem, and the more compact groups abutting on the centripetal xylem:
figs. C–E show a further reduction in the centrifugal tracheids. The
conclusion drawn from developmental study is that the two xylem portions
of the bundle are independent in origin[86]. Marsh has, however, shown that
in Stangeria bundles near the base of the petiole the centrifugal xylem
consists of rows of secondary tracheids and an inner portion not in rows
which connects the centrifugal with the centripetal elements; this
connecting portion, he adds, is ‘probably primary and connects up the
Cycadean foliar bundle with the truly mesarch bundle of the Cycadofilices.’
comprises centrifugal xylem only, and this consists of regular rows of
tracheids separated by medullary rays: in the lower part of the petiole the
structure is gradually modified, the centrifugal xylem is reduced and the
formation of centripetal xylem is initiated. At a higher level (fig. 399, B) the
centripetal xylem is in excess of the centrifugal and the latter, for a time
connected with the former, eventually becomes separated by a few
parenchymatous cells from the protoxylem and persists as a small strand or
arc of tracheids. Fig. 399 illustrates stages in the transformation of a typical
collateral bundle, at the base of a Stangeria petiole, into one in which the
xylem is almost wholly centripetal at a higher level in the axis of the frond.
A cambium is present in all: in B the centrifugal xylem is more or less
clearly differentiated into two portions, loosely arranged tracheids near the
phloem, and the more compact groups abutting on the centripetal xylem:
figs. C–E show a further reduction in the centrifugal tracheids. The
conclusion drawn from developmental study is that the two xylem portions
of the bundle are independent in origin[86]. Marsh has, however, shown that
in Stangeria bundles near the base of the petiole the centrifugal xylem
consists of rows of secondary tracheids and an inner portion not in rows
which connects the centrifugal with the centripetal elements; this
connecting portion, he adds, is ‘probably primary and connects up the
Cycadean foliar bundle with the truly mesarch bundle of the Cycadofilices.’
Page 68
Fig. 400. Cycas Micholitzii. Vascular bundles in a forked pinna; px,
protoxylem; s, sheath of thick-walled cells; cf, cp, centrifugal and
centripetal xylem.
In the xylem portion of the bundle from the midrib of a forked pinna of
Cycas Micholitzii shown in fig. 400 the centrifugal xylem elements are
unusually numerous: the space between the two xylems is occupied by
parenchyma and the whole strand is enclosed by a sheath of crystal-
containing cells, s, with thick inner walls. Fig. 400, 1–4, illustrates the
gradual change in the form of the bundle in the region of dichotomy[87]. The
ground-tissue of the petiole is abundantly supplied with secretory canals
and in the hypodermal region is a cylinder of stereome. In some petioles,
e.g. Macrozamia heteromera[88], the ground-tissue cells are lignified and
protoxylem; s, sheath of thick-walled cells; cf, cp, centrifugal and
centripetal xylem.
In the xylem portion of the bundle from the midrib of a forked pinna of
Cycas Micholitzii shown in fig. 400 the centrifugal xylem elements are
unusually numerous: the space between the two xylems is occupied by
parenchyma and the whole strand is enclosed by a sheath of crystal-
containing cells, s, with thick inner walls. Fig. 400, 1–4, illustrates the
gradual change in the form of the bundle in the region of dichotomy[87]. The
ground-tissue of the petiole is abundantly supplied with secretory canals
and in the hypodermal region is a cylinder of stereome. In some petioles,
e.g. Macrozamia heteromera[88], the ground-tissue cells are lignified and
Page 69
reticulately pitted, a feature met with in some Mesozoic cycadean leaves[89].
In Cycas media Worsdell noticed a tendency of the leaf-trace bundles
towards a concentric arrangement and similar vascular strands are recorded
in the peduncle of Dioon edule, in various sporophylls[90] and in other cases.
It is possible, as Worsdell believes, that the fairly frequent occurrence of
concentric bundles in plants characterised by collateral bundles may have a
phylogenetic significance.
The pinnae are dorsiventral and the veins exarch or pseudomesarch:
secretory canals occur between (Encephalartos), above, or below the veins.
The mesophyll of Cycas is characterised by the presence of isolated xylem-
elements passing from the midrib to the edge of the lamina and, as
Lignier[91] suggests, these may be regarded as a reduced system of lateral
conducting strands.
The epidermal cells of the leaflets have straight or slightly curved walls
except in Stangeria where they are undulate and fern-like[92]. The stomata,
with few exceptions confined to the lower epidermis, are larger than in
other gymnosperms (on the average ·075 × ·034 mm.) and are more or less
depressed below the surface; the guard-cells are usually surrounded by 4–6
subsidiary cells.
The roots exhibit no feature to which attention need be called: the
pericycle is several cells broad and as in the stem there may be
extrafascicular cylinders of xylem and phloem.
In Cycas media Worsdell noticed a tendency of the leaf-trace bundles
towards a concentric arrangement and similar vascular strands are recorded
in the peduncle of Dioon edule, in various sporophylls[90] and in other cases.
It is possible, as Worsdell believes, that the fairly frequent occurrence of
concentric bundles in plants characterised by collateral bundles may have a
phylogenetic significance.
The pinnae are dorsiventral and the veins exarch or pseudomesarch:
secretory canals occur between (Encephalartos), above, or below the veins.
The mesophyll of Cycas is characterised by the presence of isolated xylem-
elements passing from the midrib to the edge of the lamina and, as
Lignier[91] suggests, these may be regarded as a reduced system of lateral
conducting strands.
The epidermal cells of the leaflets have straight or slightly curved walls
except in Stangeria where they are undulate and fern-like[92]. The stomata,
with few exceptions confined to the lower epidermis, are larger than in
other gymnosperms (on the average ·075 × ·034 mm.) and are more or less
depressed below the surface; the guard-cells are usually surrounded by 4–6
subsidiary cells.
The roots exhibit no feature to which attention need be called: the
pericycle is several cells broad and as in the stem there may be
extrafascicular cylinders of xylem and phloem.
Page 70
Page 71
CHAPTER XXIX.
PTERIDOSPERMEAE.
I. LYGINOPTERIDEAE.
LYGINOPTERIS.
The genus Lyginopteris is selected for the first place in this chapter
simply on the ground that we have a fuller knowledge of its morphology
than in the case of other types. It is not regarded as the most primitive
member of its class. Lyginopteris may be described in a few words as a
plant having the habit and to a large extent the anatomical features of a
Fern, but differing from existing ferns in the possession of integumented
megasporangia or seeds and in the power of secondary growth in thickness
by means of a cambium in both stem and root. The seed (Lagenostoma)
agrees with those of recent Cycads and Gnetales more closely than with the
corresponding organs in Conifers or any other group, while the structure of
the secondary wood is practically identical with that of Cycads. The
microsporangia occur as groups of small bilocular sporangia, or synangia,
at the tips of fertile pinnae of highly compound fronds.
Nomenclature and Historical Summary. In 1866 E. W. Binney[93] of
Manchester published a short description of a small petrified stem from the
Lower Coal Measures of Lancashire and named it Dadoxylon oldhamium,
employing Endlicher’s term Dadoxylon which that author substituted for
Pinites as previously used by Witham[94]. Three years later Williamson[95]
drew attention to certain features in which Binney’s type differs from the
genus Dadoxylon and substituted a new name Dictyoxylon, suggested by the
reticulate pitting on the walls of the tracheids. In a subsequent paper
Williamson[96] gave a fuller description of Binney’s species and spoke of it
as ‘one of the most common plants in the calcareous nodules of the Lower
Coal Measures’ of Lancashire and Yorkshire. He connected certain casts of
arborescent dimensions with Binney’s type on the ground that the surface-
features of the casts are such as would be produced by partially decorticated
stems having a hypodermal reticulum of mechanical tissue like that
PTERIDOSPERMEAE.
I. LYGINOPTERIDEAE.
LYGINOPTERIS.
The genus Lyginopteris is selected for the first place in this chapter
simply on the ground that we have a fuller knowledge of its morphology
than in the case of other types. It is not regarded as the most primitive
member of its class. Lyginopteris may be described in a few words as a
plant having the habit and to a large extent the anatomical features of a
Fern, but differing from existing ferns in the possession of integumented
megasporangia or seeds and in the power of secondary growth in thickness
by means of a cambium in both stem and root. The seed (Lagenostoma)
agrees with those of recent Cycads and Gnetales more closely than with the
corresponding organs in Conifers or any other group, while the structure of
the secondary wood is practically identical with that of Cycads. The
microsporangia occur as groups of small bilocular sporangia, or synangia,
at the tips of fertile pinnae of highly compound fronds.
Nomenclature and Historical Summary. In 1866 E. W. Binney[93] of
Manchester published a short description of a small petrified stem from the
Lower Coal Measures of Lancashire and named it Dadoxylon oldhamium,
employing Endlicher’s term Dadoxylon which that author substituted for
Pinites as previously used by Witham[94]. Three years later Williamson[95]
drew attention to certain features in which Binney’s type differs from the
genus Dadoxylon and substituted a new name Dictyoxylon, suggested by the
reticulate pitting on the walls of the tracheids. In a subsequent paper
Williamson[96] gave a fuller description of Binney’s species and spoke of it
as ‘one of the most common plants in the calcareous nodules of the Lower
Coal Measures’ of Lancashire and Yorkshire. He connected certain casts of
arborescent dimensions with Binney’s type on the ground that the surface-
features of the casts are such as would be produced by partially decorticated
stems having a hypodermal reticulum of mechanical tissue like that
Page 72
preserved in the small petrified specimen described by Binney (fig. 402).
Mr Carruthers called Williamson’s attention to a paper by Mr Gourlie[97] in
which the generic name Lyginodendron is instituted for stem-casts identical
in surface-features with the fossils figured by Williamson. In spite of the
much larger dimensions of the reticulum on the casts described by Gourlie
as compared with that in the outer cortex of Binney’s stem, Williamson
concluded that Lyginodendron is ‘undoubtedly an inorganic cast of the
prosenchymatous layer of the bark of Dictyoxylon.’ It is but fair to add that
Williamson was influenced in coming to this conclusion by a discovery by
Mr Nield of a piece of a large petrified stem believed to be generically
identical with Binney’s type, but subsequently referred to a distinct
genus[98], which was comparable in size with the stems responsible for
Gourlie’s Lyginodendron casts. The type-specimen of Gourlie’s
Lyginodendron Landsburgii[99], from Carboniferous rocks at Stevenston in
Ayrshire, Scotland, is represented in fig. 401. The convex areas represent
casts of depressions in a reticulum of cortical tissue, originally occupied by
comparatively delicate cells, which decayed or shrunk more quickly than
the enclosing framework of stronger fibrous elements that remained as a
prominent reticulum and produced the depressions bounding the raised
portions of the cast. Such a cast would undoubtedly be formed by the stem
on which Binney founded his species: the radially disposed bands of thick-
walled cells seen in the outer part of the section (fig. 402) are portions of an
irregular anastomosing mechanical system, the reticulate arrangement of
which is seen in the impression of a rachis of a Lyginopteris frond shown in
fig. 405, E, and indicated in the more slender axis reproduced in fig. 404, A,
b. This reticulate form of cortical stereome on which Brongniart founded
the genus Dictyoxylon[100], a term since applied by Solms-Laubach and other
authors to a certain type of cortex not confined to a single genus of plants,
occurs also in some Palaeozoic lycopodiaceous stems[101] and in itself
cannot be regarded as a safe criterion of botanical affinity. The largest
example of Gourlie’s Lyginodendron that has come under my notice is an
incomplete sandstone cast from Upper Carboniferous strata near Harrogate
reaching a length of 100 cm. and with convex areas 13 cm. long. A similar
cast, 36 cm. broad, has recently been figured by Nathorst[102] from the Culm
of Spitzbergen, and from the Upper Devonian of Ellesmere Land the same
author has described impressions of a cortical reticulum under the name
Lyginodendron Sverdrupi[103]. These specimens are interesting as pointing to
Mr Carruthers called Williamson’s attention to a paper by Mr Gourlie[97] in
which the generic name Lyginodendron is instituted for stem-casts identical
in surface-features with the fossils figured by Williamson. In spite of the
much larger dimensions of the reticulum on the casts described by Gourlie
as compared with that in the outer cortex of Binney’s stem, Williamson
concluded that Lyginodendron is ‘undoubtedly an inorganic cast of the
prosenchymatous layer of the bark of Dictyoxylon.’ It is but fair to add that
Williamson was influenced in coming to this conclusion by a discovery by
Mr Nield of a piece of a large petrified stem believed to be generically
identical with Binney’s type, but subsequently referred to a distinct
genus[98], which was comparable in size with the stems responsible for
Gourlie’s Lyginodendron casts. The type-specimen of Gourlie’s
Lyginodendron Landsburgii[99], from Carboniferous rocks at Stevenston in
Ayrshire, Scotland, is represented in fig. 401. The convex areas represent
casts of depressions in a reticulum of cortical tissue, originally occupied by
comparatively delicate cells, which decayed or shrunk more quickly than
the enclosing framework of stronger fibrous elements that remained as a
prominent reticulum and produced the depressions bounding the raised
portions of the cast. Such a cast would undoubtedly be formed by the stem
on which Binney founded his species: the radially disposed bands of thick-
walled cells seen in the outer part of the section (fig. 402) are portions of an
irregular anastomosing mechanical system, the reticulate arrangement of
which is seen in the impression of a rachis of a Lyginopteris frond shown in
fig. 405, E, and indicated in the more slender axis reproduced in fig. 404, A,
b. This reticulate form of cortical stereome on which Brongniart founded
the genus Dictyoxylon[100], a term since applied by Solms-Laubach and other
authors to a certain type of cortex not confined to a single genus of plants,
occurs also in some Palaeozoic lycopodiaceous stems[101] and in itself
cannot be regarded as a safe criterion of botanical affinity. The largest
example of Gourlie’s Lyginodendron that has come under my notice is an
incomplete sandstone cast from Upper Carboniferous strata near Harrogate
reaching a length of 100 cm. and with convex areas 13 cm. long. A similar
cast, 36 cm. broad, has recently been figured by Nathorst[102] from the Culm
of Spitzbergen, and from the Upper Devonian of Ellesmere Land the same
author has described impressions of a cortical reticulum under the name
Lyginodendron Sverdrupi[103]. These specimens are interesting as pointing to
Page 73
the former occurrence in the Arctic regions of stems—probably
Lepidodendroid—reaching the dimensions of a fairly large tree. As
Potonié[104] pointed out, Gourlie’s generic name serves a useful purpose for
casts of stems of the type shown in fig. 401 that cannot be assigned to a
definite systematic position. The genus was first used for a specimen which
has nothing to do with the plant usually spoken of as Lyginodendron
oldhamium (Binney). Though loath to give up a name by which Binney’s
type has long been known, in spite of its retention in the second volume of
this work I feel compelled so far to conform to the recognised principles
governing nomenclature as to adopt Potonié’s generic term Lyginopteris.
Lepidodendroid—reaching the dimensions of a fairly large tree. As
Potonié[104] pointed out, Gourlie’s generic name serves a useful purpose for
casts of stems of the type shown in fig. 401 that cannot be assigned to a
definite systematic position. The genus was first used for a specimen which
has nothing to do with the plant usually spoken of as Lyginodendron
oldhamium (Binney). Though loath to give up a name by which Binney’s
type has long been known, in spite of its retention in the second volume of
this work I feel compelled so far to conform to the recognised principles
governing nomenclature as to adopt Potonié’s generic term Lyginopteris.
Page 74
Fig. 401. Lyginodendron Landsburgii. (Kidston Coll. ¾ nat. size.)
Lyginopteris oldhamia (Binney).
i. Stem.
Dadoxylon oldhamium, Binney, Proc. Lit. Phil. Manchester, vol. v. p.
1866.
113.
Lyginopteris oldhamia (Binney).
i. Stem.
Dadoxylon oldhamium, Binney, Proc. Lit. Phil. Manchester, vol. v. p.
1866.
113.
Page 75
Dictyoxylon oldhamium, Williamson, Monthly Micros. Journ. vol. ii.
1869.
p. 66.
Lyginodendron oldhamium, Williamson, Phil. Trans. Roy. Soc. vol.
1873.
clxiii. p. 404.
Lyginopteris oldhamia, Potonié, Lehrbuch der
1899.
Pflanzenpalaeontologie, p. 171.
ii. Leaf.
1828. Sphenopteris Hoeninghausi, Brongniart, Prodrome, p. 51.
1872. Edraxylon, Williamson, Proc. R. Soc. vol. xx. p. 438.
Rachiopteris aspera, Williamson, Phil. Trans. R. Soc. vol. clxiv. p.
1874.
684.
1877. Calymmatotheca Hoeninghausi, Stur, Culm Flora, ii. p. 266.
1905. Crossotheca Hoeninghausi, Kidston, Proc. R. Soc. vol. lxxvi. p. 358.
iii. Seed.
1877. Lagenostoma, Williamson, Phil. Trans. R. Soc. vol. clxvii. p. 234.
Lagenostoma Lomaxi, Oliver and Scott, Proc. R. Soc. vol. lxxi. p.
1903.
477.
iv. Root.
Kaloxylon Hookeri, Williamson, Phil. Trans. R. Soc. vol. clxvi. p.
1876.
23.
1869.
p. 66.
Lyginodendron oldhamium, Williamson, Phil. Trans. Roy. Soc. vol.
1873.
clxiii. p. 404.
Lyginopteris oldhamia, Potonié, Lehrbuch der
1899.
Pflanzenpalaeontologie, p. 171.
ii. Leaf.
1828. Sphenopteris Hoeninghausi, Brongniart, Prodrome, p. 51.
1872. Edraxylon, Williamson, Proc. R. Soc. vol. xx. p. 438.
Rachiopteris aspera, Williamson, Phil. Trans. R. Soc. vol. clxiv. p.
1874.
684.
1877. Calymmatotheca Hoeninghausi, Stur, Culm Flora, ii. p. 266.
1905. Crossotheca Hoeninghausi, Kidston, Proc. R. Soc. vol. lxxvi. p. 358.
iii. Seed.
1877. Lagenostoma, Williamson, Phil. Trans. R. Soc. vol. clxvii. p. 234.
Lagenostoma Lomaxi, Oliver and Scott, Proc. R. Soc. vol. lxxi. p.
1903.
477.
iv. Root.
Kaloxylon Hookeri, Williamson, Phil. Trans. R. Soc. vol. clxvi. p.
1876.
23.
Page 76
Fig. 402. Lyginopteris oldhamia. Transverse section of the type-
specimen in the Binney Collection, Sedgwick Museum,
Cambridge. (After Arber.)
i. Stem.
The petrified stem on which Binney founded the species was first figured
by Dr Arber[105] from a section in the Binney collection in the Sedgwick
Museum, Cambridge: this section (13 mm. in diameter) is reproduced in
fig. 402. The most striking features are: (i) the pith consisting of an
unusually large and irregular group of dark thick-walled parenchyma, (ii)
the broad cylinder of manoxylic secondary xylem characterised by
multiseriate medullary rays, (iii) the outer cortex composed of dark radially
disposed and oblique bands of mechanical tissue separated from one
another by partially destroyed and tangentially elongated parenchymatous
elements. It is this outer cortex that Williamson aptly compared with the
Roman numerals on a clock-face. In the perimedullary region and in contact
specimen in the Binney Collection, Sedgwick Museum,
Cambridge. (After Arber.)
i. Stem.
The petrified stem on which Binney founded the species was first figured
by Dr Arber[105] from a section in the Binney collection in the Sedgwick
Museum, Cambridge: this section (13 mm. in diameter) is reproduced in
fig. 402. The most striking features are: (i) the pith consisting of an
unusually large and irregular group of dark thick-walled parenchyma, (ii)
the broad cylinder of manoxylic secondary xylem characterised by
multiseriate medullary rays, (iii) the outer cortex composed of dark radially
disposed and oblique bands of mechanical tissue separated from one
another by partially destroyed and tangentially elongated parenchymatous
elements. It is this outer cortex that Williamson aptly compared with the
Roman numerals on a clock-face. In the perimedullary region and in contact
Page 77
with the inner edge of the secondary-xylem cylinder are six strands of
primary xylem representing the xylem halves of collateral bundles
separated from the primary phloem strands by the intervening cylinder of
secondary wood. Two of the primary xylem strands in lateral contact are
seen in fig. 404, C; the other four occur as separate bundles. Each primary
xylem strand contains a small group of spirally thickened protoxylem
elements (px) associated with a few parenchymatous cells. The large
primary tracheids internal to the protoxylem are characterised by
multiseriate bordered pits on their walls, while those external to the
protoxylem, which are in contact with the innermost secondary tracheids,
have scalariform pitting. The dark patch s (fig. 404, C) is a portion of the
large group of sclerenchymatous cells, shown in figs. 402, 403. The
perimedullary xylem strands of mesarch structure are the lower portions of
leaf-traces and, as Scott points out, ‘each of the bundles surrounding the
pith is, in fact, a sympodium, composed of the united lower ends of
successive adjacent leaf-traces.’ The larger of the two bundles shown in fig.
404, C, is on the point of passing out to a leaf, while the smaller strand is on
its way to a higher level before bending outwards through the secondary
wood. Slightly beyond the middle of the secondary xylem there is an arc of
narrower tracheids comparable with an incomplete annual ring. Although
zones or arcs of narrow tracheids are not uncommon in the wood of
Lyginopteris there is no satisfactory evidence of regularly recurring
seasonal changes. On the outer face of the secondary wood are a few leaf-
trace strands pursuing a vertical course in the pericycle region; but the
structure and behaviour of these bundles are more clearly illustrated in the
stem reproduced in fig. 403. The tissue between the crushed phloem and
pericycle and the outer cortex (fig. 402) consists of radially compressed
parenchyma with scattered secretory cells separated from the more internal
tissue by a narrow band of periderm formed by a phellogen in the outer part
of the pericycle.
A larger and better preserved stem, 3·7 cm. in diameter, is seen in fig.
403. In this stem the pith of parenchyma and scattered sclerenchymatous
nests is larger in proportion to the stele than in Binney’s type-specimen.
From the inner edge of the secondary xylem several primary xylem-strands
project as rounded wedges or tangentially elongated groups where two
traces are laterally united in the perimedullary zone. The cylinder of
secondary wood is partially interrupted at r by the bending outwards of the
primary xylem representing the xylem halves of collateral bundles
separated from the primary phloem strands by the intervening cylinder of
secondary wood. Two of the primary xylem strands in lateral contact are
seen in fig. 404, C; the other four occur as separate bundles. Each primary
xylem strand contains a small group of spirally thickened protoxylem
elements (px) associated with a few parenchymatous cells. The large
primary tracheids internal to the protoxylem are characterised by
multiseriate bordered pits on their walls, while those external to the
protoxylem, which are in contact with the innermost secondary tracheids,
have scalariform pitting. The dark patch s (fig. 404, C) is a portion of the
large group of sclerenchymatous cells, shown in figs. 402, 403. The
perimedullary xylem strands of mesarch structure are the lower portions of
leaf-traces and, as Scott points out, ‘each of the bundles surrounding the
pith is, in fact, a sympodium, composed of the united lower ends of
successive adjacent leaf-traces.’ The larger of the two bundles shown in fig.
404, C, is on the point of passing out to a leaf, while the smaller strand is on
its way to a higher level before bending outwards through the secondary
wood. Slightly beyond the middle of the secondary xylem there is an arc of
narrower tracheids comparable with an incomplete annual ring. Although
zones or arcs of narrow tracheids are not uncommon in the wood of
Lyginopteris there is no satisfactory evidence of regularly recurring
seasonal changes. On the outer face of the secondary wood are a few leaf-
trace strands pursuing a vertical course in the pericycle region; but the
structure and behaviour of these bundles are more clearly illustrated in the
stem reproduced in fig. 403. The tissue between the crushed phloem and
pericycle and the outer cortex (fig. 402) consists of radially compressed
parenchyma with scattered secretory cells separated from the more internal
tissue by a narrow band of periderm formed by a phellogen in the outer part
of the pericycle.
A larger and better preserved stem, 3·7 cm. in diameter, is seen in fig.
403. In this stem the pith of parenchyma and scattered sclerenchymatous
nests is larger in proportion to the stele than in Binney’s type-specimen.
From the inner edge of the secondary xylem several primary xylem-strands
project as rounded wedges or tangentially elongated groups where two
traces are laterally united in the perimedullary zone. The cylinder of
secondary wood is partially interrupted at r by the bending outwards of the
Page 78
stele of an adventitious root cut across transversely as it bends down after
emerging from the outer cortical region. In more or less close association
with the outer surface of the secondary xylem are four pairs of leaf-trace
bundles and one larger trace at d containing two widely separated
protoxylem strands and faced externally with an arc of secondary xylem:
this is a leaf-trace which shows by the slight constriction on the outer edge
of its primary xylem that it is beginning to divide into a pair of equal
strands. A precisely similar strand is shown on a larger scale in fig. 404, D.
The twin bundles seen at b, fig. 403, represent a divided leaf-trace at a
slightly higher level than the partially severed trace at d, and the arcs of
secondary xylem are narrower. The appearance of the double leaf-trace at a
still higher level is shown at c: the two strands are farther apart and the
secondary xylem has almost disappeared, while those at e, nearer their
entrance into the leaf-stalk, consist exclusively of primary xylem and
phloem. At a the two strands of a leaf-trace, still nearer to the petiole, are
inclined towards one another preparatory to reunion after reaching the leaf-
stalk. A slender root is seen in transverse section at r′ immediately outside
the two leaf-bundles. As Williamson and Scott[106] have pointed out, there
are always five leaf-traces beyond the xylem cylinder of a Lyginopteris
stem as seen in transverse section, and these traces in the pericycle,
separated from one another by ⅔ of the circumference, alternate in position
with the lower portions of leaf-traces in the perimedullary region of the
same stem. The phyllotaxis is thus seen to be ⅖.
emerging from the outer cortical region. In more or less close association
with the outer surface of the secondary xylem are four pairs of leaf-trace
bundles and one larger trace at d containing two widely separated
protoxylem strands and faced externally with an arc of secondary xylem:
this is a leaf-trace which shows by the slight constriction on the outer edge
of its primary xylem that it is beginning to divide into a pair of equal
strands. A precisely similar strand is shown on a larger scale in fig. 404, D.
The twin bundles seen at b, fig. 403, represent a divided leaf-trace at a
slightly higher level than the partially severed trace at d, and the arcs of
secondary xylem are narrower. The appearance of the double leaf-trace at a
still higher level is shown at c: the two strands are farther apart and the
secondary xylem has almost disappeared, while those at e, nearer their
entrance into the leaf-stalk, consist exclusively of primary xylem and
phloem. At a the two strands of a leaf-trace, still nearer to the petiole, are
inclined towards one another preparatory to reunion after reaching the leaf-
stalk. A slender root is seen in transverse section at r′ immediately outside
the two leaf-bundles. As Williamson and Scott[106] have pointed out, there
are always five leaf-traces beyond the xylem cylinder of a Lyginopteris
stem as seen in transverse section, and these traces in the pericycle,
separated from one another by ⅔ of the circumference, alternate in position
with the lower portions of leaf-traces in the perimedullary region of the
same stem. The phyllotaxis is thus seen to be ⅖.
Page 79
Fig. 403. Lyginopteris oldhamia. a–e, foliar bundles; f, decurrent base of
petiole; r, r′, roots; s, seed (Lagenostoma). (× 3. Kidston Coll. 592,
B.)
The secondary wood is succeeded by a cambium of normal structure
passing gradually into a narrow band of secondary phloem which in well-
preserved stems is seen to consist of sieve-tubes and parenchyma with
medullary rays rather broader than those in the xylem. Beyond the phloem
petiole; r, r′, roots; s, seed (Lagenostoma). (× 3. Kidston Coll. 592,
B.)
The secondary wood is succeeded by a cambium of normal structure
passing gradually into a narrow band of secondary phloem which in well-
preserved stems is seen to consist of sieve-tubes and parenchyma with
medullary rays rather broader than those in the xylem. Beyond the phloem
Page 80
is the comparatively broad pericycle consisting of parenchyma with nests of
sclerenchyma like those in the pith and scattered secretory cells. In the outer
layers of the pericycle a phellogen was formed at an early stage in the
growth of the plant, producing several layers of secondary tissue, which is
regarded as periderm and forms a conspicuous feature in Lyginopteris
stems; it appears as a comparatively dark sinuous band where it bends
outwards to wrap round the leaf-traces in their almost vertical course
through the pericyclic region (fig. 403). The periderm is clearly seen at p
close to the crushed secondary phloem of the dividing leaf-trace in fig. 404,
D. All the leaf-traces seen in fig. 403 beyond the secondary wood are still
within the deep-seated periderm and, as Williamson and Scott showed, each
leaf-trace after emerging from the secondary wood remains in the pericycle-
zone for a length of five internodes as it very gradually inclines outwards.
Once free from this region the twin bundles bend more sharply towards the
petiole. Stated briefly, the history of each leaf-trace from the perimedullary
region to the leaf-base is as follows: at the outer edge of the pith a single
trace consists of a mesarch xylem bundle with one protoxylem strand; it
passes vertically through five internodes and then bends out through a foliar
gap in the xylem-cylinder, and the primary tracheids receive additions from
the cambium of the stele on their outer face. As the trace leaves the
secondary xylem it bends upwards and, as seen at d, fig. 403, begins to
divide into twin bundles. As the trace passes higher the bisection of the
protoxylem and metaxylem is completed and the secondary xylem-arcs are
gradually lost until the separate strands of each pair are reduced to single
mesarch bundles composed wholly of primary tracheids. As the trace bends
outwards through the cortex the phloem gradually encircles each xylem-
strand until a concentric structure is substituted for the collateral disposition
of the conducting tissue. At the same time the protoxylem strands divide
and occupy a position near the inner edge of the metaxylem. On reaching
the petiole or after passing some distance up the axis of the frond, the twin
bundles unite and usually form a V-shaped vascular strand (figs. 404, E;
405, A). The single meristele subsequently divides into two equal portions
preparatory to the bifurcation of the petiole (fig. 406).
The inner cortex, consisting of parenchymatous tissue and many
secretory cells with an occasional group of sclerenchymatous elements in
place of the abundant nests of this tissue in the pericycle, has been invaded
in the stem shown in fig. 403 by numerous rootlets of Stigmaria and
sclerenchyma like those in the pith and scattered secretory cells. In the outer
layers of the pericycle a phellogen was formed at an early stage in the
growth of the plant, producing several layers of secondary tissue, which is
regarded as periderm and forms a conspicuous feature in Lyginopteris
stems; it appears as a comparatively dark sinuous band where it bends
outwards to wrap round the leaf-traces in their almost vertical course
through the pericyclic region (fig. 403). The periderm is clearly seen at p
close to the crushed secondary phloem of the dividing leaf-trace in fig. 404,
D. All the leaf-traces seen in fig. 403 beyond the secondary wood are still
within the deep-seated periderm and, as Williamson and Scott showed, each
leaf-trace after emerging from the secondary wood remains in the pericycle-
zone for a length of five internodes as it very gradually inclines outwards.
Once free from this region the twin bundles bend more sharply towards the
petiole. Stated briefly, the history of each leaf-trace from the perimedullary
region to the leaf-base is as follows: at the outer edge of the pith a single
trace consists of a mesarch xylem bundle with one protoxylem strand; it
passes vertically through five internodes and then bends out through a foliar
gap in the xylem-cylinder, and the primary tracheids receive additions from
the cambium of the stele on their outer face. As the trace leaves the
secondary xylem it bends upwards and, as seen at d, fig. 403, begins to
divide into twin bundles. As the trace passes higher the bisection of the
protoxylem and metaxylem is completed and the secondary xylem-arcs are
gradually lost until the separate strands of each pair are reduced to single
mesarch bundles composed wholly of primary tracheids. As the trace bends
outwards through the cortex the phloem gradually encircles each xylem-
strand until a concentric structure is substituted for the collateral disposition
of the conducting tissue. At the same time the protoxylem strands divide
and occupy a position near the inner edge of the metaxylem. On reaching
the petiole or after passing some distance up the axis of the frond, the twin
bundles unite and usually form a V-shaped vascular strand (figs. 404, E;
405, A). The single meristele subsequently divides into two equal portions
preparatory to the bifurcation of the petiole (fig. 406).
The inner cortex, consisting of parenchymatous tissue and many
secretory cells with an occasional group of sclerenchymatous elements in
place of the abundant nests of this tissue in the pericycle, has been invaded
in the stem shown in fig. 403 by numerous rootlets of Stigmaria and
Page 81
Lyginopteris, some of which are seen interrupting the continuity of the outer
cortex. The greater width of the cortical region at f, fig. 403, is due to the
decurrent base of a petiole the meristele of which is not included in the
section. The lighter and broader bands between the cross-sections of the
stereome-network in the outer cortex are occupied by remains of
tangentially stretched parenchymatous cells, and beyond this zone in a
younger stem there are a few layers of parenchyma forming the superficial
tissue, but there appears to be no well-defined epidermal layer.
cortex. The greater width of the cortical region at f, fig. 403, is due to the
decurrent base of a petiole the meristele of which is not included in the
section. The lighter and broader bands between the cross-sections of the
stereome-network in the outer cortex are occupied by remains of
tangentially stretched parenchymatous cells, and beyond this zone in a
younger stem there are a few layers of parenchyma forming the superficial
tissue, but there appears to be no well-defined epidermal layer.
Page 82
Fig. 404. Lyginopteris oldhamia.
A, B. Frond fragments; a, pinnule; b, reticulum of sclerenchyma.
C. Portion of stele of the stem reproduced in fig. 402.
D. px, protoxylem; s, sclerenchyma; leaf-trace close to the edge of the
secondary xylem; p, periderm.
E. Petiole; m, meristele.
A, B. Frond fragments; a, pinnule; b, reticulum of sclerenchyma.
C. Portion of stele of the stem reproduced in fig. 402.
D. px, protoxylem; s, sclerenchyma; leaf-trace close to the edge of the
secondary xylem; p, periderm.
E. Petiole; m, meristele.
Page 83
(A, Kidston Coll. 664 B; B, Camb. Botany School 508; C, Binney Coll.
179; D, E, Camb. Botany School, 93, 159.)
Young stems have been recognised in which there is very little secondary
xylem and phloem: in these the stereome bands in the outer cortex are
closer together than in the stretched hypodermal tissue of older shoots and
the scattered sclerous nests are represented by unthickened cells. In addition
to young stems Williamson and Scott described a distinct type of small stem
in which the primary xylem forms an almost complete ring[107] comparable
with the primary xylem of some adult Sigillarian stems (vol. ii. p. 220) but
distinguished by its mesarch structure and by the reticulate pitting of the
centripetal xylem.
A characteristic feature of the stem is the occurrence of emergences from
the outer cortex which have the structure either of spinous processes,
broadly linear or flask-shaped, or of stalked glands[108]. A portion of a
glandular emergence is shown in fig. 405, B: the group of small cells
immediately below the blunt apex is in this instance still intact though
showing signs of disorganisation in the centre; but in many cases the
secretory tissue has not been preserved and the head of the emergence is
occupied by a space. A single stoma is seen at s in longitudinal section.
Further reference to the emergences is made in the description of the leaf.
It occasionally happens that a meristematic layer is formed in the
parenchymatous tissue immediately internal to some of the perimedullary
xylem strands of a Lyginopteris stem from which either secondary
parenchyma is produced or a zone of secondary xylem and phloem, the
phloem facing the centre of the pith. An example of such internal xylem
was figured by Williamson[109] and similar occurrences are more fully dealt
with by Williamson and Scott[110] who consider that the perimedullary
cambium may represent an internal extension through a leaf-gap of the
normal cambial cylinder. In the stem represented in fig. 403 there are two
perimedullary xylem strands to the left of the bottom of the V-shaped gap in
the secondary xylem-cylinder, r, and on the inner face of one of these, as
shown in fig. 405, C, there is a narrow arc of internal secondary xylem, c,
between the xylem-strand and the outer edge of one of the sclerous nests.
The sporadic occurrence of arcs of inversely orientated secondary vascular
tissue affords an interesting parallel with a similar morphological feature in
179; D, E, Camb. Botany School, 93, 159.)
Young stems have been recognised in which there is very little secondary
xylem and phloem: in these the stereome bands in the outer cortex are
closer together than in the stretched hypodermal tissue of older shoots and
the scattered sclerous nests are represented by unthickened cells. In addition
to young stems Williamson and Scott described a distinct type of small stem
in which the primary xylem forms an almost complete ring[107] comparable
with the primary xylem of some adult Sigillarian stems (vol. ii. p. 220) but
distinguished by its mesarch structure and by the reticulate pitting of the
centripetal xylem.
A characteristic feature of the stem is the occurrence of emergences from
the outer cortex which have the structure either of spinous processes,
broadly linear or flask-shaped, or of stalked glands[108]. A portion of a
glandular emergence is shown in fig. 405, B: the group of small cells
immediately below the blunt apex is in this instance still intact though
showing signs of disorganisation in the centre; but in many cases the
secretory tissue has not been preserved and the head of the emergence is
occupied by a space. A single stoma is seen at s in longitudinal section.
Further reference to the emergences is made in the description of the leaf.
It occasionally happens that a meristematic layer is formed in the
parenchymatous tissue immediately internal to some of the perimedullary
xylem strands of a Lyginopteris stem from which either secondary
parenchyma is produced or a zone of secondary xylem and phloem, the
phloem facing the centre of the pith. An example of such internal xylem
was figured by Williamson[109] and similar occurrences are more fully dealt
with by Williamson and Scott[110] who consider that the perimedullary
cambium may represent an internal extension through a leaf-gap of the
normal cambial cylinder. In the stem represented in fig. 403 there are two
perimedullary xylem strands to the left of the bottom of the V-shaped gap in
the secondary xylem-cylinder, r, and on the inner face of one of these, as
shown in fig. 405, C, there is a narrow arc of internal secondary xylem, c,
between the xylem-strand and the outer edge of one of the sclerous nests.
The sporadic occurrence of arcs of inversely orientated secondary vascular
tissue affords an interesting parallel with a similar morphological feature in
Page 84
some recent Dicotyledonous genera such as Tecoma and Iodes. As
Williamson and Scott point out, this similarity affords ‘a striking warning
against the indiscriminate use of even conspicuous anatomical
characters[111].’ While admitting the necessity of guarding against the danger
of attaching importance to occasional and abnormal characters they may
have some significance as collateral evidence in comparisons of different
types of stems. It is conceivable that these anomalous arcs of secondary
tissue on the inner side of the primary xylem strands may, as Worsdell[112]
maintains, be reversions to an ancestral character and in this sense
comparable with the strands of inverted vascular tissue in some recent
Cycadean stems. The question of relationship of Lyginopteris and allied
types to recent Cycads and the Palaeozoic Medulloseae is considered in a
later chapter.
In 1902 Lomax[113] described two branching specimens of Lyginopteris,
and more recently two others have been discovered at a locality near Bacup
in Lancashire which have been thoroughly investigated by Miss
Brenchley[114] who constructed models from drawings of serial sections[115].
One specimen shows six leaf-bases in a length of 4¾ inches and branches
spring from the axils of five of them: some of the branches show secondary
ramifications. The phyllotaxis of the leaf-bases on a branch is always the
reverse of that on the main stem, a divergence to which no parallel was
found in a selection of trees and shrubs examined by Miss Brenchley. The
secondary wood of the stem swells below the point of exit of a branch and
frequently a fairly large amount of wood occurs in the pith when a branch is
given off: this anomalous wood may help to close the branch-gap.
ii. Leaf.
In his account of Lyginopteris stems published in 1873 Williamson[116]
suggested that the vascular bundles met with outside the xylem-cylinder
might be the leaf-traces of large fronds and expressed the opinion that the
‘stems or petioles’ previously described by him under the generic name
Edraxylon might belong to Lyginopteris. A year later he substituted the
name Rachiopteris aspera for the petioles previously referred to Edraxylon
and inclined to the view that this type of Rachiopteris may be the petiole of
the Carboniferous fronds known as Sphenopteris Hoeninghausi Brongn., an
inference based to a large extent on the occurrence of emergences on
Williamson and Scott point out, this similarity affords ‘a striking warning
against the indiscriminate use of even conspicuous anatomical
characters[111].’ While admitting the necessity of guarding against the danger
of attaching importance to occasional and abnormal characters they may
have some significance as collateral evidence in comparisons of different
types of stems. It is conceivable that these anomalous arcs of secondary
tissue on the inner side of the primary xylem strands may, as Worsdell[112]
maintains, be reversions to an ancestral character and in this sense
comparable with the strands of inverted vascular tissue in some recent
Cycadean stems. The question of relationship of Lyginopteris and allied
types to recent Cycads and the Palaeozoic Medulloseae is considered in a
later chapter.
In 1902 Lomax[113] described two branching specimens of Lyginopteris,
and more recently two others have been discovered at a locality near Bacup
in Lancashire which have been thoroughly investigated by Miss
Brenchley[114] who constructed models from drawings of serial sections[115].
One specimen shows six leaf-bases in a length of 4¾ inches and branches
spring from the axils of five of them: some of the branches show secondary
ramifications. The phyllotaxis of the leaf-bases on a branch is always the
reverse of that on the main stem, a divergence to which no parallel was
found in a selection of trees and shrubs examined by Miss Brenchley. The
secondary wood of the stem swells below the point of exit of a branch and
frequently a fairly large amount of wood occurs in the pith when a branch is
given off: this anomalous wood may help to close the branch-gap.
ii. Leaf.
In his account of Lyginopteris stems published in 1873 Williamson[116]
suggested that the vascular bundles met with outside the xylem-cylinder
might be the leaf-traces of large fronds and expressed the opinion that the
‘stems or petioles’ previously described by him under the generic name
Edraxylon might belong to Lyginopteris. A year later he substituted the
name Rachiopteris aspera for the petioles previously referred to Edraxylon
and inclined to the view that this type of Rachiopteris may be the petiole of
the Carboniferous fronds known as Sphenopteris Hoeninghausi Brongn., an
inference based to a large extent on the occurrence of emergences on
Page 85
Rachiopteris aspera (fig. 404, E) preserved as petrifactions like those on
impressions of Sphenopteris Hoeninghausi as figured by Brongniart (figs.
404, A; 405, D, D’). In 1890 Williamson was able to demonstrate the truth
of the surmise that Rachiopteris aspera and Lyginopteris oldhamia are
respectively the petiole and stem of the same plant, which he believed to be
an arborescent fern[117]. The petioles of Lyginopteris fronds, which may
reach a diameter of 1 cm., are attached by a broad base to the stem, and as
already suggested by the number of internodes traversed by each leaf-trace,
the leaves are comparatively far apart. A transverse section of a petiole is
shown diagrammatically in fig. 405 A. The hypodermal stereome is a
prominent feature, but the narrow radial plates of the stem-cortex tend to be
replaced in the rachis by broader and confluent masses of strengthening
elements: the upper surface of the petiole is slightly grooved. Glandular and
spinous emergences are often very abundant, as in the section reproduced in
fig. 404, E. A glandular emergence is seen at a in fig. 405, A. The spinous
emergences may be compared with those of Davallia (Odontosoria)
aculeata[118], a West Indian fern of climbing habit and with the prickles on
Hemitelia and other recent Cyatheaceous fronds[119], while capitate glands,
though simpler than those of Lyginopteris, occur on the leaf-stalks of some
recent Polypodiaceous species[120]. The concentric meristele may consist in
the lower part of the petiole of two separate and slightly curved strands like
those seen in fig. 404, E, m: sooner or later the two strands unite to form a
wide-open V or a W-shaped bundle with several slightly internal
protoxylem groups close to the lower edge. The two sections represented in
fig. 406, A and B show the gradual divergence of the two meristeles of a
petiole as they approach the level where it divides into two equal branches,
a characteristic feature of Sphenopteris Hoeninghausi and allied fronds. At
a lower level than that represented in fig. 406 the vascular strand of the
petiole would have the form of a W as figured by Williamson in one of his
earlier memoirs[121]. The phloem with scattered secretory sacs and the
adjacent tissue of the leaf-stalk are occasionally preserved in wonderful
perfection[122]. No endodermis has been recognised. Sclerous nests are
scattered in the ground-tissue as are also secretory sacs (figs. 404, E; 405,
A). A small root r has penetrated the parenchyma of the rachis shown in fig.
405, A.
impressions of Sphenopteris Hoeninghausi as figured by Brongniart (figs.
404, A; 405, D, D’). In 1890 Williamson was able to demonstrate the truth
of the surmise that Rachiopteris aspera and Lyginopteris oldhamia are
respectively the petiole and stem of the same plant, which he believed to be
an arborescent fern[117]. The petioles of Lyginopteris fronds, which may
reach a diameter of 1 cm., are attached by a broad base to the stem, and as
already suggested by the number of internodes traversed by each leaf-trace,
the leaves are comparatively far apart. A transverse section of a petiole is
shown diagrammatically in fig. 405 A. The hypodermal stereome is a
prominent feature, but the narrow radial plates of the stem-cortex tend to be
replaced in the rachis by broader and confluent masses of strengthening
elements: the upper surface of the petiole is slightly grooved. Glandular and
spinous emergences are often very abundant, as in the section reproduced in
fig. 404, E. A glandular emergence is seen at a in fig. 405, A. The spinous
emergences may be compared with those of Davallia (Odontosoria)
aculeata[118], a West Indian fern of climbing habit and with the prickles on
Hemitelia and other recent Cyatheaceous fronds[119], while capitate glands,
though simpler than those of Lyginopteris, occur on the leaf-stalks of some
recent Polypodiaceous species[120]. The concentric meristele may consist in
the lower part of the petiole of two separate and slightly curved strands like
those seen in fig. 404, E, m: sooner or later the two strands unite to form a
wide-open V or a W-shaped bundle with several slightly internal
protoxylem groups close to the lower edge. The two sections represented in
fig. 406, A and B show the gradual divergence of the two meristeles of a
petiole as they approach the level where it divides into two equal branches,
a characteristic feature of Sphenopteris Hoeninghausi and allied fronds. At
a lower level than that represented in fig. 406 the vascular strand of the
petiole would have the form of a W as figured by Williamson in one of his
earlier memoirs[121]. The phloem with scattered secretory sacs and the
adjacent tissue of the leaf-stalk are occasionally preserved in wonderful
perfection[122]. No endodermis has been recognised. Sclerous nests are
scattered in the ground-tissue as are also secretory sacs (figs. 404, E; 405,
A). A small root r has penetrated the parenchyma of the rachis shown in fig.
405, A.
Page 86
Fig. 405. Lyginopteris oldhamia. A, petiole section; a, glandular
emergence; r, root. B, stalked gland; s, stoma. C, inner edge of
wood of a stem; c, arc of inversely orientated vascular tissue. D,
D’, part of a frond of Sphenopteris Hoeninghausi. E, part of axis of
D. (A, C, D, Kidston Coll.; B, Manchester Coll. R. 645.)
emergence; r, root. B, stalked gland; s, stoma. C, inner edge of
wood of a stem; c, arc of inversely orientated vascular tissue. D,
D’, part of a frond of Sphenopteris Hoeninghausi. E, part of axis of
D. (A, C, D, Kidston Coll.; B, Manchester Coll. R. 645.)
Page 87
Fig. 406. Lyginopteris oldhamia. Transverse section illustrating
branching of petiole. × 5. (From a drawing supplied by Prof. Oliver.)
Sphenopteris Hoeninghausi Brongn.[123], founded on material from
English Coal Measures, was regarded by Williamson as the foliage of
Lyginopteris chiefly on the ground of the occurrence of emergences on the
axes (figs. 404, A, B) and laminae of the impressions like those on the
petrified stems, and this comparison received support from the resemblance
of the fragments of pinnules associated with Lyginopteris and its petioles in
the calcareous nodules to the leaflets of Brongniart’s type. This
identification is supported by subsequent work. The quadripinnate fronds,
which attain a considerable size, resemble those of recent species of
Davallia and other ferns, but the forking of the rachis and branches of the
frond is a striking feature: the pinnae may reach a length of 15 cm.[124] The
portion of carbonised rachis shown in fig. 405, E, reveals the existence of a
hypodermal reticulum like that in the outer cortex of a Lyginopteris stem
and the same feature is seen in the more slender axis represented in fig. 404,
A, at b.[125] The pinnules are usually deeply lobed and the segments may be
comparatively broad and blunt or narrow[126] (fig. 290, C, vol. ii. p. 399; fig.
404, A, a, B; fig. 405, D’). The lamina has a well marked dorsiventral
structure: the palisade-tissue next the upper surface is separated from the
epidermis by small hypodermal cells, possibly functioning as a water-
storage layer, and the central part of the mesophyll consists of loose
branching of petiole. × 5. (From a drawing supplied by Prof. Oliver.)
Sphenopteris Hoeninghausi Brongn.[123], founded on material from
English Coal Measures, was regarded by Williamson as the foliage of
Lyginopteris chiefly on the ground of the occurrence of emergences on the
axes (figs. 404, A, B) and laminae of the impressions like those on the
petrified stems, and this comparison received support from the resemblance
of the fragments of pinnules associated with Lyginopteris and its petioles in
the calcareous nodules to the leaflets of Brongniart’s type. This
identification is supported by subsequent work. The quadripinnate fronds,
which attain a considerable size, resemble those of recent species of
Davallia and other ferns, but the forking of the rachis and branches of the
frond is a striking feature: the pinnae may reach a length of 15 cm.[124] The
portion of carbonised rachis shown in fig. 405, E, reveals the existence of a
hypodermal reticulum like that in the outer cortex of a Lyginopteris stem
and the same feature is seen in the more slender axis represented in fig. 404,
A, at b.[125] The pinnules are usually deeply lobed and the segments may be
comparatively broad and blunt or narrow[126] (fig. 290, C, vol. ii. p. 399; fig.
404, A, a, B; fig. 405, D’). The lamina has a well marked dorsiventral
structure: the palisade-tissue next the upper surface is separated from the
epidermis by small hypodermal cells, possibly functioning as a water-
storage layer, and the central part of the mesophyll consists of loose
Page 88
aerenchyma: the veins are collateral as in recent ferns and stomata occur in
the lower epidermis. Emergences are seen both on impressions (fig. 405,
D’) and on petrified specimens. A striking feature of the pinnules is the
rounded surface caused by the revolute edge of the lamina as seen in the
section reproduced in fig. 404, B. This character coupled with the
occasional occurrence of groups of short tracheal elements at the
termination of the veins denotes a tendency to a xerophilous habit.
On the strength of a very close resemblance between Sphenopteris
Hoeninghausi and Calymmatotheca Stangeri (fig. 408, E, F)—characterised
by fertile pinnules bearing stellate groups of small linear valves, regarded
by Stur as the open lobes of an indusium—Zeiller included Brongniart’s
type in the genus Calymmatotheca. The resemblance in general habit
between the two species extends to the presence in their rachises of the
Dictyoxylon form of cortex[127]. The view formerly held by some authors
that the valve-like appendages to the fertile segments of Calymmatotheca
are sporangia is incorrect: a re-examination of Stur’s specimen (fig. 408, E,
F) has confirmed the original description[128]. The stellate lobes are now
regarded as portions of a cupular investment of a seed similar to
Lagenostoma Lomaxi, the female reproductive apparatus of Lyginopteris
oldhamia. The axes of the fertile pinnae bear small thorn-like emergences
probably identical with those on the cupule of Lagenostoma and on the
petioles of Lyginopteris oldhamia. It was stated in vol. ii that the fronds
known as Sphenopteris Linkii (Goepp.) represent, with other closely allied
forms, leaves belonging to Heterangium stems. This statement was based
on a misconception: the rachis of Sphenopteris Linkii, as I have satisfied
myself by an examination of impressions shown to me by Dr Kidston,
exhibits the reticulate pattern characteristic of Lyginopteris and not the
transverse ribs characteristic of Heterangium.
It is not an easy task even for those most familiar with Carboniferous
fronds to distinguish clearly between species agreeing generally with
Sphenopteris Hoeninghausi, a species regarded by some authors as the type
of a group of very similar and closely allied forms all of which were
probably borne on stems referable to the genus Lyginopteris. The species
Lyginopteris oldhamia as generally understood probably includes more than
one specific type, and it is safe to assert that in the Carboniferous period
Lyginopteris was represented by several forms characterised by highly
the lower epidermis. Emergences are seen both on impressions (fig. 405,
D’) and on petrified specimens. A striking feature of the pinnules is the
rounded surface caused by the revolute edge of the lamina as seen in the
section reproduced in fig. 404, B. This character coupled with the
occasional occurrence of groups of short tracheal elements at the
termination of the veins denotes a tendency to a xerophilous habit.
On the strength of a very close resemblance between Sphenopteris
Hoeninghausi and Calymmatotheca Stangeri (fig. 408, E, F)—characterised
by fertile pinnules bearing stellate groups of small linear valves, regarded
by Stur as the open lobes of an indusium—Zeiller included Brongniart’s
type in the genus Calymmatotheca. The resemblance in general habit
between the two species extends to the presence in their rachises of the
Dictyoxylon form of cortex[127]. The view formerly held by some authors
that the valve-like appendages to the fertile segments of Calymmatotheca
are sporangia is incorrect: a re-examination of Stur’s specimen (fig. 408, E,
F) has confirmed the original description[128]. The stellate lobes are now
regarded as portions of a cupular investment of a seed similar to
Lagenostoma Lomaxi, the female reproductive apparatus of Lyginopteris
oldhamia. The axes of the fertile pinnae bear small thorn-like emergences
probably identical with those on the cupule of Lagenostoma and on the
petioles of Lyginopteris oldhamia. It was stated in vol. ii that the fronds
known as Sphenopteris Linkii (Goepp.) represent, with other closely allied
forms, leaves belonging to Heterangium stems. This statement was based
on a misconception: the rachis of Sphenopteris Linkii, as I have satisfied
myself by an examination of impressions shown to me by Dr Kidston,
exhibits the reticulate pattern characteristic of Lyginopteris and not the
transverse ribs characteristic of Heterangium.
It is not an easy task even for those most familiar with Carboniferous
fronds to distinguish clearly between species agreeing generally with
Sphenopteris Hoeninghausi, a species regarded by some authors as the type
of a group of very similar and closely allied forms all of which were
probably borne on stems referable to the genus Lyginopteris. The species
Lyginopteris oldhamia as generally understood probably includes more than
one specific type, and it is safe to assert that in the Carboniferous period
Lyginopteris was represented by several forms characterised by highly
Page 89
compound fronds with forked rachises like Sphenopteris Linkii, S.
Hoeninghausi, and others. The features characteristic of fronds included in
the Sphenopteris Hoeninghausi group have recently been described by
Gothan[129]. Stur’s generic name Calymmatotheca originally applied to the
species C. Stangeri was applied to Sphenopteris Hoeninghausi by Zeiller,
and although the fronds of the latter type have not been found with fertile
appendages of the Calymmatotheca type there can be no doubt as to the
generic identity of these, barely distinguishable, species both of which
belong to stems of Lyginopteris. Prof. Johnson[130] has recently described
some impressions from the Coal Measures of Ireland, which he refers to S.
Hoeninghausi, bearing stellate groups of lobes like those of
Calymmatotheca, and in one case he describes a seed in the middle of the
carbonised remains of a stellate group of cupular segments. An examination
of the specimen in Dublin convinced me that there is no satisfactory
evidence of the seed-nature of the appearance on the rock believed by
Johnson to be an elliptical Lagenostoma-like seed. The actual attachment of
the stellate lobes to the pinnae of the frond is not clearly demonstrated.
iii. Microsporangia.
In 1905 Kidston[131] announced the discovery of microsporangia on
fronds of Lyginopteris: he described specimens from the Coal Measures of
Dudley identified by him with Sphenopteris Hoeninghausi showing sterile
and fertile pinnae in organic connexion. The fertile pinnules (fig. 407, B)
are slightly expanded distally into an oval limb about 2 mm. long bearing 6
to 7 bilocular fusiform microsporangia 3 mm. long and 1·5 mm. broad: in
the immature condition the sorus is hemispherical, the summit being formed
of the incurved apices of the sporangia. At maturity the sporangia spread
out, the sorus assuming the form of an epaulet. Fig. 408, H, shows a sorus
in transverse section and in fig. 408, G, the limb and two pendulous
sporangia are shown. The microspores, 50–70 µ in diameter, are studded
with numerous blunt spines and each spore shows a triradiate ridge. The
section reproduced in fig. 407, A, from the Coal Measures of Oldham is
probably a bilocular sporangium of the same type as those described by
Kidston from Dudley. Dr Kidston[132] describes a second type of
microsporangial sorus as Crossotheca Hughesiana which agrees closely
with C. Hoeninghausi, but the fertile segments are not associated with any
Hoeninghausi, and others. The features characteristic of fronds included in
the Sphenopteris Hoeninghausi group have recently been described by
Gothan[129]. Stur’s generic name Calymmatotheca originally applied to the
species C. Stangeri was applied to Sphenopteris Hoeninghausi by Zeiller,
and although the fronds of the latter type have not been found with fertile
appendages of the Calymmatotheca type there can be no doubt as to the
generic identity of these, barely distinguishable, species both of which
belong to stems of Lyginopteris. Prof. Johnson[130] has recently described
some impressions from the Coal Measures of Ireland, which he refers to S.
Hoeninghausi, bearing stellate groups of lobes like those of
Calymmatotheca, and in one case he describes a seed in the middle of the
carbonised remains of a stellate group of cupular segments. An examination
of the specimen in Dublin convinced me that there is no satisfactory
evidence of the seed-nature of the appearance on the rock believed by
Johnson to be an elliptical Lagenostoma-like seed. The actual attachment of
the stellate lobes to the pinnae of the frond is not clearly demonstrated.
iii. Microsporangia.
In 1905 Kidston[131] announced the discovery of microsporangia on
fronds of Lyginopteris: he described specimens from the Coal Measures of
Dudley identified by him with Sphenopteris Hoeninghausi showing sterile
and fertile pinnae in organic connexion. The fertile pinnules (fig. 407, B)
are slightly expanded distally into an oval limb about 2 mm. long bearing 6
to 7 bilocular fusiform microsporangia 3 mm. long and 1·5 mm. broad: in
the immature condition the sorus is hemispherical, the summit being formed
of the incurved apices of the sporangia. At maturity the sporangia spread
out, the sorus assuming the form of an epaulet. Fig. 408, H, shows a sorus
in transverse section and in fig. 408, G, the limb and two pendulous
sporangia are shown. The microspores, 50–70 µ in diameter, are studded
with numerous blunt spines and each spore shows a triradiate ridge. The
section reproduced in fig. 407, A, from the Coal Measures of Oldham is
probably a bilocular sporangium of the same type as those described by
Kidston from Dudley. Dr Kidston[132] describes a second type of
microsporangial sorus as Crossotheca Hughesiana which agrees closely
with C. Hoeninghausi, but the fertile segments are not associated with any
Page 90
sterile pinnae. The generic name Crossotheca, founded by Zeiller[133] in
1883, was substituted for Sphenopteris on the ground that Brongniart’s
species S. Hoeninghausi is shown to possess sporangia of the Crossotheca
type. If Kidston’s specific determination is correct, his discovery
demonstrates that Lyginopteris fronds bore microsporangia having the
characters of Crossotheca, a type characteristic of several Carboniferous
species belonging both to the form-genera Sphenopteris and Pecopteris.
Reference has already been made to the difficulty of distinguishing between
impressions of fronds of the Sphenopteris Hoeninghausi group, a difficulty
that is illustrated by Dr Gothan’s statement[134] that the Dudley specimens of
Crossotheca are not identical in the character of the sterile pinnules with
Sphenopteris Hoeninghausi. An examination of Dr Kidston’s specimens led
me to agree with his determination; but, it may be asked, have we any
evidence of the association with Lyginopteris fronds of sporangia other than
those of the Crossotheca type? Prof. Chodat[135] believes that certain
petrified fragments of pinnules occasionally met with in the calcareous
nodules bearing sessile and apparently annulate sporangia belong to
Lyginopteris fronds. These sporangia appear to be identical with those
named by Scott Pteridotheca Butterworthi[136] and regarded by him as
filicean sporangia that cannot be referred to any known Carboniferous
genus. The piece of lamina bearing an empty sporangium, which may or
may not have possessed an annulus, reproduced in fig. 407, C, occurs in
association with the larger specimen shown in fig. 404, B, and it would
seem not unreasonable to regard both as parts of the same frond, namely a
frond of Lyginopteris. As Prof. Weiss[137] points out, the accurate
determination of small pieces of petrified pinnules is exceedingly difficult
and without more decisive evidence we are hardly justified in asserting that
the sporangia figured by Chodat and Scott and that shown in fig. 407
belong to the genus Lyginopteris. Although the available data appear to
favour the view generally held that Kidston’s conclusion is correct
additional evidence would be welcome.
1883, was substituted for Sphenopteris on the ground that Brongniart’s
species S. Hoeninghausi is shown to possess sporangia of the Crossotheca
type. If Kidston’s specific determination is correct, his discovery
demonstrates that Lyginopteris fronds bore microsporangia having the
characters of Crossotheca, a type characteristic of several Carboniferous
species belonging both to the form-genera Sphenopteris and Pecopteris.
Reference has already been made to the difficulty of distinguishing between
impressions of fronds of the Sphenopteris Hoeninghausi group, a difficulty
that is illustrated by Dr Gothan’s statement[134] that the Dudley specimens of
Crossotheca are not identical in the character of the sterile pinnules with
Sphenopteris Hoeninghausi. An examination of Dr Kidston’s specimens led
me to agree with his determination; but, it may be asked, have we any
evidence of the association with Lyginopteris fronds of sporangia other than
those of the Crossotheca type? Prof. Chodat[135] believes that certain
petrified fragments of pinnules occasionally met with in the calcareous
nodules bearing sessile and apparently annulate sporangia belong to
Lyginopteris fronds. These sporangia appear to be identical with those
named by Scott Pteridotheca Butterworthi[136] and regarded by him as
filicean sporangia that cannot be referred to any known Carboniferous
genus. The piece of lamina bearing an empty sporangium, which may or
may not have possessed an annulus, reproduced in fig. 407, C, occurs in
association with the larger specimen shown in fig. 404, B, and it would
seem not unreasonable to regard both as parts of the same frond, namely a
frond of Lyginopteris. As Prof. Weiss[137] points out, the accurate
determination of small pieces of petrified pinnules is exceedingly difficult
and without more decisive evidence we are hardly justified in asserting that
the sporangia figured by Chodat and Scott and that shown in fig. 407
belong to the genus Lyginopteris. Although the available data appear to
favour the view generally held that Kidston’s conclusion is correct
additional evidence would be welcome.
Page 91
Fig. 407.
A, B. Crossotheca Hoeninghausi.
C. Pinnule with a sporangium, s.
(A, Kidston Coll. 1277; B, after Kidston; C, Camb. Botany School,
508.)
Telangium. Reference was made in vol. ii.[138] to the genus Telangium
instituted by Dr Benson for some petrified sporangia from the Coal
Measures regarded by her as the microsporangia of a Pteridosperm,
probably Lyginopteris. The sporangia of Telangium are similar to those of
A, B. Crossotheca Hoeninghausi.
C. Pinnule with a sporangium, s.
(A, Kidston Coll. 1277; B, after Kidston; C, Camb. Botany School,
508.)
Telangium. Reference was made in vol. ii.[138] to the genus Telangium
instituted by Dr Benson for some petrified sporangia from the Coal
Measures regarded by her as the microsporangia of a Pteridosperm,
probably Lyginopteris. The sporangia of Telangium are similar to those of
Page 92
Crossotheca. Scott points out that they are borne on a flat disc or lamina
‘quite comparable to a fertile pinna of Crossotheca[139],’ and he concludes
that these sporangia are not generically distinct from the impressions on
which the genus Crossotheca was founded. Kidston[140] regards Telangium
Scotti, Benson, as the microsporangium of a Pteridosperm though not of
Lyginopteris, on the ground that the microsporangia described by Miss
Benson are not attached to a limb and that they have a single loculus in
place of the double loculus (fig. 407, A) of Crossotheca. The presence of a
limb in Telangium recognised by Scott removes one of these distinguishing
features. There are, however, no adequate reasons for regarding Telangium
Scotti as specifically identical with Crossotheca Hoeninghausi. The
synangium of Telangium Scotti, 5 mm. in length, consists of 6–12 sporangia
united basally and opening when ripe by longitudinal dehiscence. Fig. 493,
E, shows eight sporangia of a synangium in transverse section: the two
sporangia at the lower end of the section are less distinct than the others,
some are full of spores and others have shed their contents by the splitting
of the thin inner walls of the loculi. The sporangial walls are composed of
an outer layer of large cells with dark contents succeeded by 2–3 layers of
smaller and crushed cells. The spores, 5–6 µ × 3·5–4 µ in diameter, have a
reticulately sculptured exine: Dr Benson[141] states that they agree closely
with pollen-grains found in the pollen-chamber of Lagenostoma ovoides
except in their slightly smaller size; she notes the association of Telangium
with fragments of the vegetative organs of Lyginopteris and draws attention
to resemblances in the structure of the tissues; but the most interesting
comparison, at least in an academic sense, is with the seed Lagenostoma,
the integumented megasporangium of Lyginopteris. Dr Benson points out
that a transverse section of a Lagenostoma in the plane of the canopy,
showing the nucellar apex surrounded by radially disposed chambers (fig.
409), presents a certain resemblance to a synangium of Telangium Scotti;
and it is suggested that the chambers encircling the nucellus may represent
sterilised sister-sporangia[142]. ‘The seed in fact is assumed to be a
synangium in which all but one of the sporangia are sterile, and form an
integument to the one fertile sporangium which has become a
megasporangium with one large megaspore.’ This view, though clearly
incapable of confirmation in the present state of our knowledge, is not
merely an ingenious hypothesis but a stimulating suggestion as to possible
homologies: as an argument in favour of associating Lagenostoma and
‘quite comparable to a fertile pinna of Crossotheca[139],’ and he concludes
that these sporangia are not generically distinct from the impressions on
which the genus Crossotheca was founded. Kidston[140] regards Telangium
Scotti, Benson, as the microsporangium of a Pteridosperm though not of
Lyginopteris, on the ground that the microsporangia described by Miss
Benson are not attached to a limb and that they have a single loculus in
place of the double loculus (fig. 407, A) of Crossotheca. The presence of a
limb in Telangium recognised by Scott removes one of these distinguishing
features. There are, however, no adequate reasons for regarding Telangium
Scotti as specifically identical with Crossotheca Hoeninghausi. The
synangium of Telangium Scotti, 5 mm. in length, consists of 6–12 sporangia
united basally and opening when ripe by longitudinal dehiscence. Fig. 493,
E, shows eight sporangia of a synangium in transverse section: the two
sporangia at the lower end of the section are less distinct than the others,
some are full of spores and others have shed their contents by the splitting
of the thin inner walls of the loculi. The sporangial walls are composed of
an outer layer of large cells with dark contents succeeded by 2–3 layers of
smaller and crushed cells. The spores, 5–6 µ × 3·5–4 µ in diameter, have a
reticulately sculptured exine: Dr Benson[141] states that they agree closely
with pollen-grains found in the pollen-chamber of Lagenostoma ovoides
except in their slightly smaller size; she notes the association of Telangium
with fragments of the vegetative organs of Lyginopteris and draws attention
to resemblances in the structure of the tissues; but the most interesting
comparison, at least in an academic sense, is with the seed Lagenostoma,
the integumented megasporangium of Lyginopteris. Dr Benson points out
that a transverse section of a Lagenostoma in the plane of the canopy,
showing the nucellar apex surrounded by radially disposed chambers (fig.
409), presents a certain resemblance to a synangium of Telangium Scotti;
and it is suggested that the chambers encircling the nucellus may represent
sterilised sister-sporangia[142]. ‘The seed in fact is assumed to be a
synangium in which all but one of the sporangia are sterile, and form an
integument to the one fertile sporangium which has become a
megasporangium with one large megaspore.’ This view, though clearly
incapable of confirmation in the present state of our knowledge, is not
merely an ingenious hypothesis but a stimulating suggestion as to possible
homologies: as an argument in favour of associating Lagenostoma and
Page 93
Telangium as the spore-bearing organs of the same plant it has but little
weight.
iv. The Seed. Lagenostoma Williamson.
Lagenostoma Lomaxi, Oliver and Scott ex Williamson, ms.
In 1877 Williamson[143] proposed the generic name Lagenostoma for
some petrified seeds from the Lower Coal Measures of Lancashire and
described two species, Lagenostoma ovoides and L. physoides: in his ms.
Catalogue a third type is referred to as Lagenostoma Lomaxi. It is this third
type that Prof. Oliver was the first to recognise as the megaspore-bearing
organ of Lyginopteris oldhamia. Its structure has been thoroughly described
by Oliver and Scott[144] and these authors contribute a judicial summary of
the evidence on which Lagenostoma and Lyginopteris are believed to stand
for one and the same plant. The evidence is based chiefly on the following
considerations: an agreement in the structure of the vascular bundles in the
investments of the seed with those in the leaves of Lyginopteris; the
presence in the outer envelope of the seed of stalked glands identical with
those on the stems and petioles. The evidence does not as yet amount to
absolute proof, as the seeds, which occur either with or without a stalk,
have not been found attached to a Lyginopteris frond. But ‘where vegetative
and reproductive organs presenting identical structural features, not known
to occur in other plants, are thus found in close and constant association, the
inference that the one belonged to the other appears irresistible.’ While most
botanists believe that a satisfactory case is established there are a few[145]
who refuse to believe in a connexion between Lagenostoma and
Lyginopteris until an actual union has been demonstrated. The discovery by
Kidston[146] of seeds attached to pinnae bearing Neuropteris pinnules and the
demonstration of organic continuity between seeds and the pinnules of other
Palaeozoic fern-like fronds supply abundant confirmatory evidence that
leaves no doubt as to the occurrence of seeds on modified pinnae of
Sphenopteris Hoeninghausi and of other closely allied fronds which
represent the foliage of different forms of Lyginopteris. In this connexion it
is pertinent to add that Grand’Eury[147] has found seeds of the Lagenostoma
type in close association with impressions of Sphenopteris Dubuissonis and
other leaves of similar habit.
weight.
iv. The Seed. Lagenostoma Williamson.
Lagenostoma Lomaxi, Oliver and Scott ex Williamson, ms.
In 1877 Williamson[143] proposed the generic name Lagenostoma for
some petrified seeds from the Lower Coal Measures of Lancashire and
described two species, Lagenostoma ovoides and L. physoides: in his ms.
Catalogue a third type is referred to as Lagenostoma Lomaxi. It is this third
type that Prof. Oliver was the first to recognise as the megaspore-bearing
organ of Lyginopteris oldhamia. Its structure has been thoroughly described
by Oliver and Scott[144] and these authors contribute a judicial summary of
the evidence on which Lagenostoma and Lyginopteris are believed to stand
for one and the same plant. The evidence is based chiefly on the following
considerations: an agreement in the structure of the vascular bundles in the
investments of the seed with those in the leaves of Lyginopteris; the
presence in the outer envelope of the seed of stalked glands identical with
those on the stems and petioles. The evidence does not as yet amount to
absolute proof, as the seeds, which occur either with or without a stalk,
have not been found attached to a Lyginopteris frond. But ‘where vegetative
and reproductive organs presenting identical structural features, not known
to occur in other plants, are thus found in close and constant association, the
inference that the one belonged to the other appears irresistible.’ While most
botanists believe that a satisfactory case is established there are a few[145]
who refuse to believe in a connexion between Lagenostoma and
Lyginopteris until an actual union has been demonstrated. The discovery by
Kidston[146] of seeds attached to pinnae bearing Neuropteris pinnules and the
demonstration of organic continuity between seeds and the pinnules of other
Palaeozoic fern-like fronds supply abundant confirmatory evidence that
leaves no doubt as to the occurrence of seeds on modified pinnae of
Sphenopteris Hoeninghausi and of other closely allied fronds which
represent the foliage of different forms of Lyginopteris. In this connexion it
is pertinent to add that Grand’Eury[147] has found seeds of the Lagenostoma
type in close association with impressions of Sphenopteris Dubuissonis and
other leaves of similar habit.
Page 94
A seed of Lagenostoma Lomaxi reaches a length of 5·5 mm. with a
maximum diameter of 4·4 mm.; it is broadly oval or barrel-like (fig. 408, C)
and when immature was invested by a loose irregularly lobed glandular
envelope (fig. 408, B) from which the seed eventually freed itself by a
natural process of abscission. The central body or nucellus, except in the
apical region, is concrescent with a fairly stout integument or testa (fig. 408,
C, f) the outer portion of which is characterised by regular longitudinal rows
of palisade-like cells comparable with the broad palisade-layer in the
sporocarp of Pilularia. On the exposed surface of this palisade-tissue are
small dark structureless pegs[148], possibly the remains of a mucilaginous
layer such as occurs on the seed-coats of some recent Flowering plants. At
the base of the nucellus the chalazal region, fig. 408, C, ch, is provided with
sclerous elements and forms a hard investment to the axial vascular strand
from the pedicel. It is at the base of this chalazal region that the seed is
eventually cut off by an absciss-layer. The integument is supplied
throughout its length by nine vascular bundles of endarch, or approximately
endarch, structure. The free portion of the integument seen from the outside
(fig. 408, B) has the form of a fluted cone with a circular opening at its
summit. The greater part of this domical apex, as seen in longitudinal
section in fig. 408, C, appears to be hollow, but in the living state the dome,
or canopy as Williamson called it, was filled with parenchyma in which the
vascular bundles were embedded and, as shown in the transverse section in
fig. 409, the canopy is divided into compartments by radial septa which in
its basal region are replaced by regular and deep furrows on the inner face.
Enclosed by the canopy, with its outer surface fluted as the result of the
partial collapse of the outer wall of each compartment due to the decay of
the filling tissue, is the flask-shaped apex of the nucellus; between the
apical cone of nucellar parenchyma and the superficial layer is an annular
cavity which Williamson[149] called the lagenostome. The parenchymatous
core tapers to a narrow summit which slightly overtops the integument and
is constricted at the broad base (fig. 493, A, B; page 311). The bottle-shaped
apical tissue is separated by an annular space, c, fig. 493, B, from the
limiting layer of the nucellus: this space is the pollen-chamber formed in
the living seed by the disorganisation of the subepidermal cells of the
nucellar apex. The pollen-chamber is a feature characteristic of recent
cycadean ovules (see p. 6). In Lagenostoma the annular form of the pollen-
chamber is a peculiarity distinguishing this type of seed from those of
maximum diameter of 4·4 mm.; it is broadly oval or barrel-like (fig. 408, C)
and when immature was invested by a loose irregularly lobed glandular
envelope (fig. 408, B) from which the seed eventually freed itself by a
natural process of abscission. The central body or nucellus, except in the
apical region, is concrescent with a fairly stout integument or testa (fig. 408,
C, f) the outer portion of which is characterised by regular longitudinal rows
of palisade-like cells comparable with the broad palisade-layer in the
sporocarp of Pilularia. On the exposed surface of this palisade-tissue are
small dark structureless pegs[148], possibly the remains of a mucilaginous
layer such as occurs on the seed-coats of some recent Flowering plants. At
the base of the nucellus the chalazal region, fig. 408, C, ch, is provided with
sclerous elements and forms a hard investment to the axial vascular strand
from the pedicel. It is at the base of this chalazal region that the seed is
eventually cut off by an absciss-layer. The integument is supplied
throughout its length by nine vascular bundles of endarch, or approximately
endarch, structure. The free portion of the integument seen from the outside
(fig. 408, B) has the form of a fluted cone with a circular opening at its
summit. The greater part of this domical apex, as seen in longitudinal
section in fig. 408, C, appears to be hollow, but in the living state the dome,
or canopy as Williamson called it, was filled with parenchyma in which the
vascular bundles were embedded and, as shown in the transverse section in
fig. 409, the canopy is divided into compartments by radial septa which in
its basal region are replaced by regular and deep furrows on the inner face.
Enclosed by the canopy, with its outer surface fluted as the result of the
partial collapse of the outer wall of each compartment due to the decay of
the filling tissue, is the flask-shaped apex of the nucellus; between the
apical cone of nucellar parenchyma and the superficial layer is an annular
cavity which Williamson[149] called the lagenostome. The parenchymatous
core tapers to a narrow summit which slightly overtops the integument and
is constricted at the broad base (fig. 493, A, B; page 311). The bottle-shaped
apical tissue is separated by an annular space, c, fig. 493, B, from the
limiting layer of the nucellus: this space is the pollen-chamber formed in
the living seed by the disorganisation of the subepidermal cells of the
nucellar apex. The pollen-chamber is a feature characteristic of recent
cycadean ovules (see p. 6). In Lagenostoma the annular form of the pollen-
chamber is a peculiarity distinguishing this type of seed from those of
Page 95
recent Gymnosperms and most other Palaeozoic seeds. As Oliver says, it
marks an ‘advance in precision’[150] over other forms as the microspores
which fall into the chamber are brought direct to the surface of the
underlying megaspore and presumably to the archegonia which, it is
reasonable to believe, were disposed in a circle at the base of the annular
crevice. Microspores frequently occur in the pollen-chamber and some have
been discovered apparently in the act of liberating male gametes[151].
marks an ‘advance in precision’[150] over other forms as the microspores
which fall into the chamber are brought direct to the surface of the
underlying megaspore and presumably to the archegonia which, it is
reasonable to believe, were disposed in a circle at the base of the annular
crevice. Microspores frequently occur in the pollen-chamber and some have
been discovered apparently in the act of liberating male gametes[151].
Page 96
Fig. 408. A, A′, Lagenospermum Sinclairi. B, Lagenostoma, restoration.
C, Lagenostoma Lomaxi; c, micropyle; d, space between
integument and nucellus; e, cupule; f, integument; ch, chalaza. D,
microspores of Lagenostoma ovoides. E, F, Calymmatotheca
Stangeri. G, H, Crossotheca Hoeninghausi. H, section of G in line
of arrow. (A, after Arber; B, C, E, F, after Oliver; D, after Benson;
G, H, after Kidston.)
C, Lagenostoma Lomaxi; c, micropyle; d, space between
integument and nucellus; e, cupule; f, integument; ch, chalaza. D,
microspores of Lagenostoma ovoides. E, F, Calymmatotheca
Stangeri. G, H, Crossotheca Hoeninghausi. H, section of G in line
of arrow. (A, after Arber; B, C, E, F, after Oliver; D, after Benson;
G, H, after Kidston.)
Page 97
Fig. 409. Lagenostoma. Transverse section near the micropyle, showing
the pollen-chamber, pc, the space, s, between the nucellus and
integument, the fluted canopy with vascular bundles, v. (After
Oliver.)
The outer wall of the nucellus is bounded externally by a similar circular
space (d, figs. 408, C; 493, B) which separates it from the domical canopy.
In the great majority of specimens the central tissue of the seed is not
preserved and an empty sac supported from the base of the nucellus-apex
occupies nearly the whole of the interior: the shrunken wall of the sac is all
that remains of the large megaspore. It would seem, then, that the nucellus
was almost completely destroyed as a consequence of the growth of the
megaspore or embryo-sac, which eventually occupied nearly the whole of
the seed-body.
In an exceptionally well preserved specimen recently described and
admirably illustrated by Mr McLean[152] part of the parenchymatous tissue
of the prothallus which originally filled the megaspore is clearly seen: its
surface-layer consists of small cells succeeded by a broad band of radially
elongated elements closely resembling the alveoli in the prothalli of some
recent Gymnosperms, particularly certain Conifers. No archegonia have
been discovered. The cupular envelope of immature seeds, compared by
Oliver and Scott with the lobed and glandular husk of Corylus colurna L.
[153]
, receives several vascular bundles of collateral and mesarch structure
from the axial strand, and these subdivide as they ascend. The glands which
occur on all parts of the cupule are sessile or stalked and identical with
the pollen-chamber, pc, the space, s, between the nucellus and
integument, the fluted canopy with vascular bundles, v. (After
Oliver.)
The outer wall of the nucellus is bounded externally by a similar circular
space (d, figs. 408, C; 493, B) which separates it from the domical canopy.
In the great majority of specimens the central tissue of the seed is not
preserved and an empty sac supported from the base of the nucellus-apex
occupies nearly the whole of the interior: the shrunken wall of the sac is all
that remains of the large megaspore. It would seem, then, that the nucellus
was almost completely destroyed as a consequence of the growth of the
megaspore or embryo-sac, which eventually occupied nearly the whole of
the seed-body.
In an exceptionally well preserved specimen recently described and
admirably illustrated by Mr McLean[152] part of the parenchymatous tissue
of the prothallus which originally filled the megaspore is clearly seen: its
surface-layer consists of small cells succeeded by a broad band of radially
elongated elements closely resembling the alveoli in the prothalli of some
recent Gymnosperms, particularly certain Conifers. No archegonia have
been discovered. The cupular envelope of immature seeds, compared by
Oliver and Scott with the lobed and glandular husk of Corylus colurna L.
[153]
, receives several vascular bundles of collateral and mesarch structure
from the axial strand, and these subdivide as they ascend. The glands which
occur on all parts of the cupule are sessile or stalked and identical with
Page 98
those on the vegetative organs of Lyginopteris. Assuming that pollination
occurred at a comparatively early stage in the development of the seed
when the cupule was still intact, it is conceivable, as Sir Joseph Hooker
suggested, that the glandular secretion may have attracted insects and so
aided in the transport of pollen which were perhaps drawn down the narrow
pollen-chamber by exuded mucilage as in recent Conifers. The evidence
obtained in recent years in favour of insect-pollination in certain Cycads
and in Welwitschia lends support to this view: the dragon flies hovering
over a fertile Lyginopteris frond in a recent restoration[154] may be a
legitimate addition.
A striking feature of Lagenostoma as of other Palaeozoic seeds is the
absence of an embryo: this and other considerations have led certain
authors, notably Chodat[155], to question the justification for the use of the
term seed. Various suggestions have been offered in explanation of this fact.
In recent Cycads, as already pointed out, the development of the embryo
does not always occur before seed-fall. It may be that these older seeds had
no resting-period or there may have been a period of rest after fertilisation
and not as now at a stage subsequent to the formation of the embryo[156]; it is
also suggested by Scott that ‘the nursing of the embryo had not yet come to
be one of the functions of the seed, and that the whole embryonic
development was relegated to the germination stage[157].’ In this connexion
reference may be made to a statement by Miss Gibbs[158] who speaks of
seeds of a Podocarpus picked up from the ground in apparently a mature
state and with the associated bracts coloured and swollen as though ready to
aid in dispersal but with no embryo: the seeds had matured before
fertilisation and fell from the tree after pollination. Whatever may be the
true explanation of the absence of embryos this negative character should
not be allowed to outweigh the evidence furnished by morphological
features as to the applicability of the term seed. As Prof. Oliver says, ‘there
is a long chapter in evolution to be deciphered before we can connect ... the
seed of Lyginodendron with the sporangium of any fern at present known to
us’[159].
The cupule of Lagenostoma has been homologised with the outer part of
the integument of a recent cycadean seed[160] which, it is suggested, consists
of an inner and an outer envelope that have become concrescent, and this
hypothesis is supported by another author by a comparison between
occurred at a comparatively early stage in the development of the seed
when the cupule was still intact, it is conceivable, as Sir Joseph Hooker
suggested, that the glandular secretion may have attracted insects and so
aided in the transport of pollen which were perhaps drawn down the narrow
pollen-chamber by exuded mucilage as in recent Conifers. The evidence
obtained in recent years in favour of insect-pollination in certain Cycads
and in Welwitschia lends support to this view: the dragon flies hovering
over a fertile Lyginopteris frond in a recent restoration[154] may be a
legitimate addition.
A striking feature of Lagenostoma as of other Palaeozoic seeds is the
absence of an embryo: this and other considerations have led certain
authors, notably Chodat[155], to question the justification for the use of the
term seed. Various suggestions have been offered in explanation of this fact.
In recent Cycads, as already pointed out, the development of the embryo
does not always occur before seed-fall. It may be that these older seeds had
no resting-period or there may have been a period of rest after fertilisation
and not as now at a stage subsequent to the formation of the embryo[156]; it is
also suggested by Scott that ‘the nursing of the embryo had not yet come to
be one of the functions of the seed, and that the whole embryonic
development was relegated to the germination stage[157].’ In this connexion
reference may be made to a statement by Miss Gibbs[158] who speaks of
seeds of a Podocarpus picked up from the ground in apparently a mature
state and with the associated bracts coloured and swollen as though ready to
aid in dispersal but with no embryo: the seeds had matured before
fertilisation and fell from the tree after pollination. Whatever may be the
true explanation of the absence of embryos this negative character should
not be allowed to outweigh the evidence furnished by morphological
features as to the applicability of the term seed. As Prof. Oliver says, ‘there
is a long chapter in evolution to be deciphered before we can connect ... the
seed of Lyginodendron with the sporangium of any fern at present known to
us’[159].
The cupule of Lagenostoma has been homologised with the outer part of
the integument of a recent cycadean seed[160] which, it is suggested, consists
of an inner and an outer envelope that have become concrescent, and this
hypothesis is supported by another author by a comparison between
Page 99
Lagenostoma and Gnetalean seeds[161]. A comparison has also been made
between the collar of a Ginkgo seed and the much more conspicuous cupule
of Lagenostoma[162]. Dr Benson and Miss Welsford[163] institute a
comparison between the vascular supply of the outer integument of the
ovules of Carpinus and Morus and that of the cupule of Lagenostoma, a
comparison suggested by Miss Kershaw’s remarks[164] on the similarity
between the vascular system of the ovules of Myrica Gale and
Trigonocarpus. In 1908 Dr Benson[165] described some germinating
microspores in the pollen-chamber of another species of Lagenostoma, L.
ovoides, and recognised what she believed to be antherozoids. I am
indebted to this author for allowing me to make a drawing from her section
(fig. 408, D). Two microspores are seen with thick outer walls showing
irregular holes probably of secondary origin and not part of a regular
reticulum as Dr Benson suggests. Close to the upper microspore is a
hemispherical body, s, described as a male gamete, and a similar body is
seen still enclosed by the lower microspore. It is by no means improbable
that these are antherozoids: they were presumably ciliate like those of
Ginkgo and recent Cycads (fig. 396, M). The microspores are
approximately 70μ in length and the supposed antherozoids have a
maximum diameter of 45μ, the latter being about ⅔ the size of the sperms
of Microcycas and ⅙ the diameter of those of Zamia. The smaller and more
delicate cells near the lower microspore (fig. 408, D) are no doubt fungal
cells as Miss Benson suggests. With reference to the difficulty of
determining the nature of Miss Benson’s supposed gametes it is worth
calling attention to some figures given by Zopf[166] of vesicular cells and
sporangia of the Phycomycetous genera Rhizophidium and Lagenidium in
the pollen of Flowering plants and Pines. It has been suggested by
Burlingame[167] that the ‘gametes’ may be prothallial cells; but this is very
improbable.
Lagenostoma ovoides Williamson.
In the memoir in which the genus was founded Williamson described two
species from the Lower Coal Measures of Lancashire, Lagenostoma
ovoides and L. physoides[168]. The seeds described under the latter name had
previously been assigned by him to another new genus, Physostoma, and
named P. elegans[169]. Lagenostoma physoides was afterwards figured by
Butterworth[170] who recognised some new features. For this species Prof.
between the collar of a Ginkgo seed and the much more conspicuous cupule
of Lagenostoma[162]. Dr Benson and Miss Welsford[163] institute a
comparison between the vascular supply of the outer integument of the
ovules of Carpinus and Morus and that of the cupule of Lagenostoma, a
comparison suggested by Miss Kershaw’s remarks[164] on the similarity
between the vascular system of the ovules of Myrica Gale and
Trigonocarpus. In 1908 Dr Benson[165] described some germinating
microspores in the pollen-chamber of another species of Lagenostoma, L.
ovoides, and recognised what she believed to be antherozoids. I am
indebted to this author for allowing me to make a drawing from her section
(fig. 408, D). Two microspores are seen with thick outer walls showing
irregular holes probably of secondary origin and not part of a regular
reticulum as Dr Benson suggests. Close to the upper microspore is a
hemispherical body, s, described as a male gamete, and a similar body is
seen still enclosed by the lower microspore. It is by no means improbable
that these are antherozoids: they were presumably ciliate like those of
Ginkgo and recent Cycads (fig. 396, M). The microspores are
approximately 70μ in length and the supposed antherozoids have a
maximum diameter of 45μ, the latter being about ⅔ the size of the sperms
of Microcycas and ⅙ the diameter of those of Zamia. The smaller and more
delicate cells near the lower microspore (fig. 408, D) are no doubt fungal
cells as Miss Benson suggests. With reference to the difficulty of
determining the nature of Miss Benson’s supposed gametes it is worth
calling attention to some figures given by Zopf[166] of vesicular cells and
sporangia of the Phycomycetous genera Rhizophidium and Lagenidium in
the pollen of Flowering plants and Pines. It has been suggested by
Burlingame[167] that the ‘gametes’ may be prothallial cells; but this is very
improbable.
Lagenostoma ovoides Williamson.
In the memoir in which the genus was founded Williamson described two
species from the Lower Coal Measures of Lancashire, Lagenostoma
ovoides and L. physoides[168]. The seeds described under the latter name had
previously been assigned by him to another new genus, Physostoma, and
named P. elegans[169]. Lagenostoma physoides was afterwards figured by
Butterworth[170] who recognised some new features. For this species Prof.
Page 100
Oliver[171] has adopted Williamson’s earlier name, Physostoma elegans. The
former species, which has recently received exhaustive treatment by Miss
Prankerd[172], agrees generally in its morphological characters with L.
Lomaxi, but differs in the structure of the surface-tissue of the integument
and in some anatomical features. Moreover no cupules have been found and
there is ‘very little trace of a layer of separation’ such as occurs in L.
Lomaxi. Over the surface of the integument is a layer of prismatic cells,
much shorter and less palisade-like than those in L. Lomaxi, and there are
none of the pegs which are a constant feature in that species. There are,
however, indications that mucilage was poured out by the rupture of the
distended cells. Some microspores were found in the pollen-chamber with
an average size of 72 × 53μ; they may be as much as 90μ long. None were
observed with sperm-like contents like those described by Dr Benson. Miss
Prankerd discusses the morphology of the integument in relation to that of
cycadean seeds and makes an instructive comparison between the
lagenostome (that is the modified nucellar apex) and such fern sporangia as
those of Angiopteris, Osmunda, and Schizaea, but especially the sporangia
of Senftenbergia[173] with their multiseriate annulus.
An interesting feature is shown in the longitudinal section reproduced in
fig. 493, A (p. 311). The apex of the nucellar cone appears to be composed
of thick-walled, dark cells and it is suggested that this may have served as a
stopper blocking up the circular orifice of the pollen-chamber (seen below
the apex between the nucellar cone and the thick surface-layer of the
nucellus) and serving as a protection to the embryo. A comparable closing-
up of the micropyle occurs in the seeds of Gnetum Gnemon[174] and in the
beak of cycadean seeds. At the time of pollination, when the pollen-
chamber must have extended to the apex of the lagenostome, the tip of the
nucellar cone may have secreted some sticky substance to which the
microspores would adhere.
Prof. Lignier[175] has recently described some large megasporangia from
the Westphalian Coalfield of Ostrau in Austrian Silesia which he made the
type of a new genus Mittagia, after Herr Mittag, Director of Mines. Two
sporangia, between 2 and 3 mm. in diameter, were found in close
association as though belonging to a single sorus; one was empty and the
other contained four megaspores. The structure of the thick wall of the
sporangia is very similar to that of the testa of Lagenostoma Lomaxi, but it
former species, which has recently received exhaustive treatment by Miss
Prankerd[172], agrees generally in its morphological characters with L.
Lomaxi, but differs in the structure of the surface-tissue of the integument
and in some anatomical features. Moreover no cupules have been found and
there is ‘very little trace of a layer of separation’ such as occurs in L.
Lomaxi. Over the surface of the integument is a layer of prismatic cells,
much shorter and less palisade-like than those in L. Lomaxi, and there are
none of the pegs which are a constant feature in that species. There are,
however, indications that mucilage was poured out by the rupture of the
distended cells. Some microspores were found in the pollen-chamber with
an average size of 72 × 53μ; they may be as much as 90μ long. None were
observed with sperm-like contents like those described by Dr Benson. Miss
Prankerd discusses the morphology of the integument in relation to that of
cycadean seeds and makes an instructive comparison between the
lagenostome (that is the modified nucellar apex) and such fern sporangia as
those of Angiopteris, Osmunda, and Schizaea, but especially the sporangia
of Senftenbergia[173] with their multiseriate annulus.
An interesting feature is shown in the longitudinal section reproduced in
fig. 493, A (p. 311). The apex of the nucellar cone appears to be composed
of thick-walled, dark cells and it is suggested that this may have served as a
stopper blocking up the circular orifice of the pollen-chamber (seen below
the apex between the nucellar cone and the thick surface-layer of the
nucellus) and serving as a protection to the embryo. A comparable closing-
up of the micropyle occurs in the seeds of Gnetum Gnemon[174] and in the
beak of cycadean seeds. At the time of pollination, when the pollen-
chamber must have extended to the apex of the lagenostome, the tip of the
nucellar cone may have secreted some sticky substance to which the
microspores would adhere.
Prof. Lignier[175] has recently described some large megasporangia from
the Westphalian Coalfield of Ostrau in Austrian Silesia which he made the
type of a new genus Mittagia, after Herr Mittag, Director of Mines. Two
sporangia, between 2 and 3 mm. in diameter, were found in close
association as though belonging to a single sorus; one was empty and the
other contained four megaspores. The structure of the thick wall of the
sporangia is very similar to that of the testa of Lagenostoma Lomaxi, but it
Page 101
apparently split into two valves. Lignier refers the new type, Mittagia
seminiformis, to some unknown Palaeozoic group of heterosporous
Filicineae, possibly the ancestral stock of the Pteridosperms, and he thinks
it probable that the sporangia resembled seeds in their facilities for
dispersal. In the structure of the sporangial wall Mittagia also resembles the
sporocarp of Pilularia.
Seeds presented as impressions, without internal structure, superficially
resembling Lagenostoma.
Lagenospermum Nathorst.
This generic name is adopted for seeds represented by casts or
impressions agreeing in external features with Lagenostoma but which on
the available evidence cannot be confidently assigned to that genus[176]. Two
types of seed were described by Arber[177] from the Lower Coal Measures of
Scotland as Lagenostoma Kidstoni and L. Sinclairi: the former has been
removed by Oliver[178] to Physostoma and both are included by Arber[179] in
a recent paper in the genus Radiospermum. This new generic term is
proposed by Arber for a number of small sub-cylindrical seeds founded on
impressions including ‘small seeds which, when the structure is preserved,
are known as Lagenostoma, Physostoma, and Conostoma.’ The question of
nomenclature is invariably raised by cases in which impressions resemble
in their superficial characters genera founded on anatomical characters: the
seeds originally referred to Lagenostoma Sinclairi afford a good example of
this difficulty. Nathorst has recently proposed the generic name
Lagenospermum as preferable to Lagenostoma and Radiospermum in the
case of Lagenostoma Sinclairi and similar seeds which afford no proof of
the possession of such morphological characters as would justify their
inclusion in the genus Lagenostoma but which may be examples of that
genus. As Nathorst points out, the adoption of Radiospermum for L.
Sinclairi is inadvisable on the ground that it is also applied to seeds of a
different type. The type-species of Lagenospermum is L. Sinclairi and
Nathorst describes additional species from Lower Carboniferous rocks in
Spitzbergen.
Lagenospermum Sinclairi (Arber ex Kidston ms.).
seminiformis, to some unknown Palaeozoic group of heterosporous
Filicineae, possibly the ancestral stock of the Pteridosperms, and he thinks
it probable that the sporangia resembled seeds in their facilities for
dispersal. In the structure of the sporangial wall Mittagia also resembles the
sporocarp of Pilularia.
Seeds presented as impressions, without internal structure, superficially
resembling Lagenostoma.
Lagenospermum Nathorst.
This generic name is adopted for seeds represented by casts or
impressions agreeing in external features with Lagenostoma but which on
the available evidence cannot be confidently assigned to that genus[176]. Two
types of seed were described by Arber[177] from the Lower Coal Measures of
Scotland as Lagenostoma Kidstoni and L. Sinclairi: the former has been
removed by Oliver[178] to Physostoma and both are included by Arber[179] in
a recent paper in the genus Radiospermum. This new generic term is
proposed by Arber for a number of small sub-cylindrical seeds founded on
impressions including ‘small seeds which, when the structure is preserved,
are known as Lagenostoma, Physostoma, and Conostoma.’ The question of
nomenclature is invariably raised by cases in which impressions resemble
in their superficial characters genera founded on anatomical characters: the
seeds originally referred to Lagenostoma Sinclairi afford a good example of
this difficulty. Nathorst has recently proposed the generic name
Lagenospermum as preferable to Lagenostoma and Radiospermum in the
case of Lagenostoma Sinclairi and similar seeds which afford no proof of
the possession of such morphological characters as would justify their
inclusion in the genus Lagenostoma but which may be examples of that
genus. As Nathorst points out, the adoption of Radiospermum for L.
Sinclairi is inadvisable on the ground that it is also applied to seeds of a
different type. The type-species of Lagenospermum is L. Sinclairi and
Nathorst describes additional species from Lower Carboniferous rocks in
Spitzbergen.
Lagenospermum Sinclairi (Arber ex Kidston ms.).
Page 102
Although it is not certain that these seeds are morphologically identical
with the genus Lagenostoma, a brief description is intercalated here as the
habit of the seed-bearing axes supplies a probable key to the habit of the
fertile fronds of Lyginopteris. The type-specimens were collected by Mr
Sinclair from the Lower Coal Measures of Ayrshire, Scotland, and recorded
by Kidston as Lagenostoma sp.: they were afterwards named by him in
manuscript L. Sinclairi and handed to Dr Arber for description. The seeds
are elliptical-oblong, 4–5·5 × 1·5–3 mm., radially symmetrical and
enclosed by a loose envelope which is longitudinally ribbed and divided
distally into several linear-lanceolate lobes (fig. 408, A, A′). This covering,
though much longer than the cupule of Lagenostoma Lomaxi, is probably a
homologous structure. The most interesting point is the attachment of the
seeds to slender branches of a compound axis (fig. 408, A). It is probable
that the seeds were borne on a frond characterised by the reduction or
complete abortion of the sterile lamina or perhaps, as in the recent Fern
Thyrsopteris elegans[180], some of the pinnae of a large compound frond
were fertile. It is worthy of note that Arber recognised pinnules of
Sphenopteris obtusiloba[181] in association with L. Sinclairi, a fact, as he
says, in itself of no value but which acquires significance in view of the
discovery by Carpentier[182] of cupules in close proximity to the same
species of frond. Specimens described by Dr Stopes from Westphalian rocks
of New Brunswick as Pterispermostrobus bifurcatus[183] bear a close
resemblance to L. Sinclairi.
Lagenospermum oblongum (Kidston).
The species recently described by Dr Kidston[184] as Lagenostoma
oblonga from the South Staffordshire coal-field appears to be closely allied
to Arber’s L. Sinclairi: it is represented by pairs of seeds borne at the ends
of forked branchlets: the seed is 2·5 mm. long by 1·5 mm. broad and is
surrounded by a longer oblong cupule divided distally into 6 free lobes.
A larger type of seed, 3 cm. long and 2·5 cm. broad, is described by
Kidston[185] from the same coal-field as Lagenostoma? urceolaris. A
characteristic feature is the truncate apex surrounded by a prominent
canopy formed of the expanded apical free portion of the integument. The
lack of anatomical data in both these seeds is a reason for the substitution of
some less committal term than Lagenostoma.
with the genus Lagenostoma, a brief description is intercalated here as the
habit of the seed-bearing axes supplies a probable key to the habit of the
fertile fronds of Lyginopteris. The type-specimens were collected by Mr
Sinclair from the Lower Coal Measures of Ayrshire, Scotland, and recorded
by Kidston as Lagenostoma sp.: they were afterwards named by him in
manuscript L. Sinclairi and handed to Dr Arber for description. The seeds
are elliptical-oblong, 4–5·5 × 1·5–3 mm., radially symmetrical and
enclosed by a loose envelope which is longitudinally ribbed and divided
distally into several linear-lanceolate lobes (fig. 408, A, A′). This covering,
though much longer than the cupule of Lagenostoma Lomaxi, is probably a
homologous structure. The most interesting point is the attachment of the
seeds to slender branches of a compound axis (fig. 408, A). It is probable
that the seeds were borne on a frond characterised by the reduction or
complete abortion of the sterile lamina or perhaps, as in the recent Fern
Thyrsopteris elegans[180], some of the pinnae of a large compound frond
were fertile. It is worthy of note that Arber recognised pinnules of
Sphenopteris obtusiloba[181] in association with L. Sinclairi, a fact, as he
says, in itself of no value but which acquires significance in view of the
discovery by Carpentier[182] of cupules in close proximity to the same
species of frond. Specimens described by Dr Stopes from Westphalian rocks
of New Brunswick as Pterispermostrobus bifurcatus[183] bear a close
resemblance to L. Sinclairi.
Lagenospermum oblongum (Kidston).
The species recently described by Dr Kidston[184] as Lagenostoma
oblonga from the South Staffordshire coal-field appears to be closely allied
to Arber’s L. Sinclairi: it is represented by pairs of seeds borne at the ends
of forked branchlets: the seed is 2·5 mm. long by 1·5 mm. broad and is
surrounded by a longer oblong cupule divided distally into 6 free lobes.
A larger type of seed, 3 cm. long and 2·5 cm. broad, is described by
Kidston[185] from the same coal-field as Lagenostoma? urceolaris. A
characteristic feature is the truncate apex surrounded by a prominent
canopy formed of the expanded apical free portion of the integument. The
lack of anatomical data in both these seeds is a reason for the substitution of
some less committal term than Lagenostoma.
Page 103
Grand’Eury[186] and Carpentier[187] have published accounts of
impressions of seeds from the Coal Measures of France compared by them
with species of Lagenostoma though not assigned to new species. These and
similar seeds should be referred to Nathorst’s genus Lagenospermum.
The difficulty of recognising the true nature of seed-like impressions is
illustrated by some specimens in the Goldenberg collection in Stockholm
described by Arber[188] as Carpolithus Nathorsti: these consist of pieces of
Sphenopteris pinnae probably, as Zeiller suggested, Sphenopteris
Schaumburg-Lippeana (Stur) bearing at the ends of the segments of deeply
divided pinnules what appeared to be seeds 1 mm. long, oval and
longitudinally ribbed, and possibly enclosed in a cupule. Arber considered
the ‘seeds’ to be related to Lagenostoma, probably belonging to some
member of the Lyginopterideae. An examination of the specimens by
Nathorst[189] showed that the supposed seeds are collections of spores; but
whether the spores of a true Fern or the microspores of a Pteridosperm
cannot be determined.
Pterispermostrobus Stopes.
Pterispermostrobus bifurcatus Stopes.
Dr Stopes[190] has recently called attention to a resemblance between
specimens from the Westphalian of New Brunswick, described by her as
Pterispermostrobus bifurcatus, and Lagenospermum Sinclairi. The New
Brunswick fossil is made the type of a new genus Pterispermostrobus,
which is employed for fructifications of Pteridosperms that cannot be
associated with a known species of parent and may be either seeds or
complex male organs borne on a definitely branched rachis. The type-
species is represented by a slender axis bearing lateral branches divided into
two widely divergent arms each of which bears a terminal body, 4 × 3 mm.,
characterised by 3–5 apical lobes extending 2 mm. beyond the distal end of
the seed-like organ and resembling a cupule. In this as in many other cases
it is impossible to determine the true nature of the reproductive bodies,
whether they are small seeds or groups of microsporangia: the new generic
name serves a useful purpose though it is not always possible definitely to
refer doubtful fructifications of this kind to a Pteridosperm. The organs in
question may also be compared with Codonotheca[191].
impressions of seeds from the Coal Measures of France compared by them
with species of Lagenostoma though not assigned to new species. These and
similar seeds should be referred to Nathorst’s genus Lagenospermum.
The difficulty of recognising the true nature of seed-like impressions is
illustrated by some specimens in the Goldenberg collection in Stockholm
described by Arber[188] as Carpolithus Nathorsti: these consist of pieces of
Sphenopteris pinnae probably, as Zeiller suggested, Sphenopteris
Schaumburg-Lippeana (Stur) bearing at the ends of the segments of deeply
divided pinnules what appeared to be seeds 1 mm. long, oval and
longitudinally ribbed, and possibly enclosed in a cupule. Arber considered
the ‘seeds’ to be related to Lagenostoma, probably belonging to some
member of the Lyginopterideae. An examination of the specimens by
Nathorst[189] showed that the supposed seeds are collections of spores; but
whether the spores of a true Fern or the microspores of a Pteridosperm
cannot be determined.
Pterispermostrobus Stopes.
Pterispermostrobus bifurcatus Stopes.
Dr Stopes[190] has recently called attention to a resemblance between
specimens from the Westphalian of New Brunswick, described by her as
Pterispermostrobus bifurcatus, and Lagenospermum Sinclairi. The New
Brunswick fossil is made the type of a new genus Pterispermostrobus,
which is employed for fructifications of Pteridosperms that cannot be
associated with a known species of parent and may be either seeds or
complex male organs borne on a definitely branched rachis. The type-
species is represented by a slender axis bearing lateral branches divided into
two widely divergent arms each of which bears a terminal body, 4 × 3 mm.,
characterised by 3–5 apical lobes extending 2 mm. beyond the distal end of
the seed-like organ and resembling a cupule. In this as in many other cases
it is impossible to determine the true nature of the reproductive bodies,
whether they are small seeds or groups of microsporangia: the new generic
name serves a useful purpose though it is not always possible definitely to
refer doubtful fructifications of this kind to a Pteridosperm. The organs in
question may also be compared with Codonotheca[191].
Page 104
Pterispermostrobus pusillus (Nathorst).
The name, Codonotheca pusilla, is given by Nathorst[192] to some
doubtful specimens from the Culm of Spitzbergen representing short stalks
bearing linear-lanceolate scale-like bodies, 9–10 mm. long by 1 mm. broad,
coalescent at the base. Nathorst compares them with Sellard’s species,
Codonotheca caduca, but adds that they may be cupules of some
Pteridosperm and calls attention to their resemblance to some fossils
figured by Carpentier as Calymmatotheca acuta. Both Nathorst’s species
and the French specimens described by Carpentier[193] as cupules may be
referred to Dr Stopes’ genus Pterispermostrobus as their morphological
nature cannot be determined.
v. Roots.
In 1876 Williamson[194] described some petrified vegetative organs from
the Lower Coal Measures of Lancashire under the name Kaloxylon Hookeri
characterised by a division of the secondary xylem into cuneate masses (fig.
415, C) like those in some recent Bignoniaceous stems. Williamson at first
believed Kaloxylon to be a stem, but in a later memoir he expressed the
opinion that ‘it is difficult to believe that these organs have been other than
roots’[195]. Felix[196] had meanwhile described a specimen from the Coal
Measures of Westphalia as Kaloxylon cf. Hookeri and suggested that it
might be a waterplant. In 1894 Williamson and Scott[197] demonstrated that
Kaloxylon Hookeri is the root of Lyginopteris, a conclusion independently
reached by Hick[198].
The roots of Lyginopteris arise on all sides of the radially symmetrical
stem in the pericycle region; they are copiously branched as is shown by the
abundance of roots of various sizes in close association. No roots have been
discovered exceeding 1 cm. in diameter nor have any been recorded with
secondary periderm-tissue. The absence of root-hairs and the more or less
lacunar structure of the cortex are indicative of swampy ground. It is
seldom that the palaeobotanist has an opportunity of investigating the
growing-points of Palaeozoic plants, and for this reason some well-
preserved apices of Lyginopteris roots, attributed to that genus on the
ground of constant association with fragments of stems in the calcareous
nodules of Dulesgate, are of special interest. One of these specimens was
The name, Codonotheca pusilla, is given by Nathorst[192] to some
doubtful specimens from the Culm of Spitzbergen representing short stalks
bearing linear-lanceolate scale-like bodies, 9–10 mm. long by 1 mm. broad,
coalescent at the base. Nathorst compares them with Sellard’s species,
Codonotheca caduca, but adds that they may be cupules of some
Pteridosperm and calls attention to their resemblance to some fossils
figured by Carpentier as Calymmatotheca acuta. Both Nathorst’s species
and the French specimens described by Carpentier[193] as cupules may be
referred to Dr Stopes’ genus Pterispermostrobus as their morphological
nature cannot be determined.
v. Roots.
In 1876 Williamson[194] described some petrified vegetative organs from
the Lower Coal Measures of Lancashire under the name Kaloxylon Hookeri
characterised by a division of the secondary xylem into cuneate masses (fig.
415, C) like those in some recent Bignoniaceous stems. Williamson at first
believed Kaloxylon to be a stem, but in a later memoir he expressed the
opinion that ‘it is difficult to believe that these organs have been other than
roots’[195]. Felix[196] had meanwhile described a specimen from the Coal
Measures of Westphalia as Kaloxylon cf. Hookeri and suggested that it
might be a waterplant. In 1894 Williamson and Scott[197] demonstrated that
Kaloxylon Hookeri is the root of Lyginopteris, a conclusion independently
reached by Hick[198].
The roots of Lyginopteris arise on all sides of the radially symmetrical
stem in the pericycle region; they are copiously branched as is shown by the
abundance of roots of various sizes in close association. No roots have been
discovered exceeding 1 cm. in diameter nor have any been recorded with
secondary periderm-tissue. The absence of root-hairs and the more or less
lacunar structure of the cortex are indicative of swampy ground. It is
seldom that the palaeobotanist has an opportunity of investigating the
growing-points of Palaeozoic plants, and for this reason some well-
preserved apices of Lyginopteris roots, attributed to that genus on the
ground of constant association with fragments of stems in the calcareous
nodules of Dulesgate, are of special interest. One of these specimens was
Page 105
figured by Dr Stopes and Mr Watson[199] in their account of plant-bearing
nodules, and a description of that and other examples has since been
published by Prof. Weiss[200]. A longitudinal section of a root-tip, ·21 mm. in
diameter at its broadest part, shows a root-cap which suggests an origin
from a single cell, but an examination of the plerome-cylinder in a slightly
tangential section does not afford conclusive evidence of the occurrence of
a single initial cell. Weiss on the whole inclines to the view that
Lyginopteris possessed a single apical cell like the roots of
Leptosporangiate Ferns, though he prefers to leave the decision open.
Attention is drawn to the fact that the plate of tracheidal tissue in emerging
lateral rootlets is vertical as in Phanerogams and not horizontal as in recent
Pteridophyta.
The vascular tissue of a Lyginopteris root (fig. 410) consists of from
three to eight alternate strands of centripetal xylem and phloem, and with
the metaxylem is associated a small amount of conjunctive parenchyma
which does not form a central pith. The pericycle, one to several layers
broad, is succeeded by an endodermis which occasionally shows the
characteristic thickenings on the radial walls. A broad cortex of thin-walled
lacunar tissue with numerous secretory cells is bounded externally by a
superficial cylinder of two or more layers of comparatively large and thin
cells, the outermost of which are radially elongated. This superficial tissue
forms a striking feature by which a Lyginopteris root may often be
recognised at a glance. The root represented in fig. 410, approximately 2
mm. in diameter, has a heptarch stele divided into seven xylem-groups by
crushed bands of parenchyma and a protoxylem strand occupies the apex of
each projecting angle (fig. 410, px). The superficial cylinder of clear cells is
seen at a. A very small root is seen at r in fig. 410.
nodules, and a description of that and other examples has since been
published by Prof. Weiss[200]. A longitudinal section of a root-tip, ·21 mm. in
diameter at its broadest part, shows a root-cap which suggests an origin
from a single cell, but an examination of the plerome-cylinder in a slightly
tangential section does not afford conclusive evidence of the occurrence of
a single initial cell. Weiss on the whole inclines to the view that
Lyginopteris possessed a single apical cell like the roots of
Leptosporangiate Ferns, though he prefers to leave the decision open.
Attention is drawn to the fact that the plate of tracheidal tissue in emerging
lateral rootlets is vertical as in Phanerogams and not horizontal as in recent
Pteridophyta.
The vascular tissue of a Lyginopteris root (fig. 410) consists of from
three to eight alternate strands of centripetal xylem and phloem, and with
the metaxylem is associated a small amount of conjunctive parenchyma
which does not form a central pith. The pericycle, one to several layers
broad, is succeeded by an endodermis which occasionally shows the
characteristic thickenings on the radial walls. A broad cortex of thin-walled
lacunar tissue with numerous secretory cells is bounded externally by a
superficial cylinder of two or more layers of comparatively large and thin
cells, the outermost of which are radially elongated. This superficial tissue
forms a striking feature by which a Lyginopteris root may often be
recognised at a glance. The root represented in fig. 410, approximately 2
mm. in diameter, has a heptarch stele divided into seven xylem-groups by
crushed bands of parenchyma and a protoxylem strand occupies the apex of
each projecting angle (fig. 410, px). The superficial cylinder of clear cells is
seen at a. A very small root is seen at r in fig. 410.
Page 106
Fig. 410. Lyginopteris oldhamia, young root. × 30. (Kidston Coll. 403.)
Fig. 415, C, represents part of an older root in which the pentarch
primary xylem is enclosed by broad wedge-like groups of secondary xylem
and phloem separated by conspicuous medullary rays opposite the
protoxylem strands (px). Crushed primary phloem arcs, p, are often clearly
recognisable beyond the cambium. The secondary thickening, as
Williamson and Scott state, ‘takes place exactly in the manner typical of
roots of Dicotyledons, so that this fossil might very well be used for
purposes of demonstration as illustrating the secondary growth of a root
with diagrammatic clearness’[201]. The young roots of Lyginopteris resemble
in many respects those of Marattiaceous Ferns, though the presence of a
single apical cell, if such occurs, is a distinguishing feature; but in the
presence of secondary conducting tissue they agree with those of
Phanerogams.
Distribution of Lyginopteris.
The frequency with which petrified fragments of Lyginopteris stems
occur in the calcareous nodules of the English coal seams shows that the
genus must have been plentifully represented in the Upper Carboniferous
Fig. 415, C, represents part of an older root in which the pentarch
primary xylem is enclosed by broad wedge-like groups of secondary xylem
and phloem separated by conspicuous medullary rays opposite the
protoxylem strands (px). Crushed primary phloem arcs, p, are often clearly
recognisable beyond the cambium. The secondary thickening, as
Williamson and Scott state, ‘takes place exactly in the manner typical of
roots of Dicotyledons, so that this fossil might very well be used for
purposes of demonstration as illustrating the secondary growth of a root
with diagrammatic clearness’[201]. The young roots of Lyginopteris resemble
in many respects those of Marattiaceous Ferns, though the presence of a
single apical cell, if such occurs, is a distinguishing feature; but in the
presence of secondary conducting tissue they agree with those of
Phanerogams.
Distribution of Lyginopteris.
The frequency with which petrified fragments of Lyginopteris stems
occur in the calcareous nodules of the English coal seams shows that the
genus must have been plentifully represented in the Upper Carboniferous
Page 107
vegetation, and the occurrence in both North American[202] and European
localities of fronds identical with or closely resembling Sphenopteris
Hoeninghausi affords evidence of wide geographical range. Petrified
specimens were recorded by Felix[203] from Westphalia in 1886, and
Zalessky[204] has recently discovered Lyginopteris in the Donetz coal-basin
of Russia. An investigation by Kubart[205] of the calcareous nodules, to
which attention was first drawn by Stur, in the Ostrau Coal Measures led to
the discovery of several examples of Lyginopteris stems. The descriptions
and figures so far published are hardly sufficient to enable us to estimate the
degree of relationship to the English type, but some of the stems appear to
be new species and Kubart considers them all to be specifically distinct
from Lyginopteris oldhamia. Lyginopteris heterangioides contains scattered
tracheids in the pith and thus affords an interesting transitional type
between Lyginopteris and Heterangium. In L. lacunosum the inner cortex is
lacunar and the primary xylem bundles pursue an independent course in the
stele in contrast to the anastomosing arrangement in L. oldhamia and in
another Hungarian species L. tristichum. The species recorded by Kubart
occur in the Millstone grit and the Coal Measures.
The geological range of Lyginopteris as represented by petrified stems
does not extend beyond the limits of the Carboniferous system.
HETERANGIUM.
The generic name Heterangium was first used by Corda[206] for a piece of
stem from the Coal Measures of Radnitz, Bohemia, represented by part of
the vascular axis of a stem consisting of strands of large reticulately pitted
tracheids intermixed with parenchyma and exhibiting structural features
differing apparently from those of any known type. Corda’s material has
been re-examined by Kubart[207] who figures a section from it. Heterangium
is a genus closely allied to Lyginopteris both in habit and in general
anatomical characters. The stem is monostelic; the vascular cylinder prior to
secondary thickening resembles the protostele of certain recent species of
Gleichenia and may be compared also with Trichomanes scandens[208]. It
agrees with that of Lyginopteris in the possession of primary mesarch
bundles but differs in the substitution of a cauline axial mass of metaxylem
for the pith of Lyginopteris. The secondary vascular tissue agrees closely
with that of recent Cycads and Lyginopteris. A characteristic feature is the
occurrence of numerous horizontal bands of sclerous cells in the cortex (fig.
localities of fronds identical with or closely resembling Sphenopteris
Hoeninghausi affords evidence of wide geographical range. Petrified
specimens were recorded by Felix[203] from Westphalia in 1886, and
Zalessky[204] has recently discovered Lyginopteris in the Donetz coal-basin
of Russia. An investigation by Kubart[205] of the calcareous nodules, to
which attention was first drawn by Stur, in the Ostrau Coal Measures led to
the discovery of several examples of Lyginopteris stems. The descriptions
and figures so far published are hardly sufficient to enable us to estimate the
degree of relationship to the English type, but some of the stems appear to
be new species and Kubart considers them all to be specifically distinct
from Lyginopteris oldhamia. Lyginopteris heterangioides contains scattered
tracheids in the pith and thus affords an interesting transitional type
between Lyginopteris and Heterangium. In L. lacunosum the inner cortex is
lacunar and the primary xylem bundles pursue an independent course in the
stele in contrast to the anastomosing arrangement in L. oldhamia and in
another Hungarian species L. tristichum. The species recorded by Kubart
occur in the Millstone grit and the Coal Measures.
The geological range of Lyginopteris as represented by petrified stems
does not extend beyond the limits of the Carboniferous system.
HETERANGIUM.
The generic name Heterangium was first used by Corda[206] for a piece of
stem from the Coal Measures of Radnitz, Bohemia, represented by part of
the vascular axis of a stem consisting of strands of large reticulately pitted
tracheids intermixed with parenchyma and exhibiting structural features
differing apparently from those of any known type. Corda’s material has
been re-examined by Kubart[207] who figures a section from it. Heterangium
is a genus closely allied to Lyginopteris both in habit and in general
anatomical characters. The stem is monostelic; the vascular cylinder prior to
secondary thickening resembles the protostele of certain recent species of
Gleichenia and may be compared also with Trichomanes scandens[208]. It
agrees with that of Lyginopteris in the possession of primary mesarch
bundles but differs in the substitution of a cauline axial mass of metaxylem
for the pith of Lyginopteris. The secondary vascular tissue agrees closely
with that of recent Cycads and Lyginopteris. A characteristic feature is the
occurrence of numerous horizontal bands of sclerous cells in the cortex (fig.
Page 108
412) of the stem and in the ground-tissue of the rachis and larger branches
of the fronds. The stem was erect and rarely branched ‘giving off large
foliar appendages at somewhat distant intervals and from its entire
circumference’[209]. Our knowledge of the reproductive organs is less precise
than in the case of Lyginopteris; but we are justified in asserting that
Heterangium is a Pteridosperm which in all probability bore fern-like
microsporangia and seeds similar in general plan to Lagenostoma.
The association of some seeds included in Williamson’s genus
Conostoma with Heterangium Grievii in the Pettycur beds and their
resemblance to Lagenostoma, the seed of Lyginopteris, suggested the
possibility of actual connexion: further evidence in support of this view has
recently been brought forward by Dr Benson[210] in the case of a species of
Conostoma which she transfers to a new genus Sphaerostoma.
The two species Heterangium Grievii and H. tiliaeoides are described in
illustration of the genus and reference is made to a few other types.
Heterangium Grievii Williamson.
(Stem.)
Dictyoxylon Grievii, Williamson, Brit. Ass. Rep. (Edinburgh
1872.
Meeting), p. 112.
Heterangium Grievii, Williamson, Phil. Trans. R. Soc. Vol. 162, p.
1873.
404.
(Leaf.)
Fumaria officinalis, Volkmann, Silesia subterranea, p. 111, Pl. xiv.
[1720.
fig. 2.]
1822. Filicites (Sphenopteris) elegans, Brongniart, Class. Vég. p. 233.
1828. Sphenopteris elegans, Brongniart, Hist. Vég. Foss. p. 172.
1836. Cheilanthites elegans, Goeppert, Foss. Farnkr. p. 233.
1877. Diplothmema elegans, Stur, Culm Flora, ii. p. 130.
i. Stem.
At the Edinburgh meeting of the British Association Williamson[211] gave
a brief account of some petrified stems from the Lower Carboniferous strata
of Burntisland on the Firth of Forth which he included in the genus
of the fronds. The stem was erect and rarely branched ‘giving off large
foliar appendages at somewhat distant intervals and from its entire
circumference’[209]. Our knowledge of the reproductive organs is less precise
than in the case of Lyginopteris; but we are justified in asserting that
Heterangium is a Pteridosperm which in all probability bore fern-like
microsporangia and seeds similar in general plan to Lagenostoma.
The association of some seeds included in Williamson’s genus
Conostoma with Heterangium Grievii in the Pettycur beds and their
resemblance to Lagenostoma, the seed of Lyginopteris, suggested the
possibility of actual connexion: further evidence in support of this view has
recently been brought forward by Dr Benson[210] in the case of a species of
Conostoma which she transfers to a new genus Sphaerostoma.
The two species Heterangium Grievii and H. tiliaeoides are described in
illustration of the genus and reference is made to a few other types.
Heterangium Grievii Williamson.
(Stem.)
Dictyoxylon Grievii, Williamson, Brit. Ass. Rep. (Edinburgh
1872.
Meeting), p. 112.
Heterangium Grievii, Williamson, Phil. Trans. R. Soc. Vol. 162, p.
1873.
404.
(Leaf.)
Fumaria officinalis, Volkmann, Silesia subterranea, p. 111, Pl. xiv.
[1720.
fig. 2.]
1822. Filicites (Sphenopteris) elegans, Brongniart, Class. Vég. p. 233.
1828. Sphenopteris elegans, Brongniart, Hist. Vég. Foss. p. 172.
1836. Cheilanthites elegans, Goeppert, Foss. Farnkr. p. 233.
1877. Diplothmema elegans, Stur, Culm Flora, ii. p. 130.
i. Stem.
At the Edinburgh meeting of the British Association Williamson[211] gave
a brief account of some petrified stems from the Lower Carboniferous strata
of Burntisland on the Firth of Forth which he included in the genus
Page 109
Dictyoxylon. One of these was named D. Grievii after Mr Grieve the
discoverer of the specimens. In a later and more complete description
Williamson adopted Corda’s generic name on the ground of the close
resemblance of the Scotch stem to the Bohemian fragment Heterangium
paradoxum. In 1873[212] Williamson added new facts in regard to H. Grievii
and in 1890[213] he described a very closely allied type from the Lower Coal
Measures of Lancashire. Five years later his descriptions were considerably
extended and modified in the joint memoir with Dr Scott[214].
The great difference in age between the English Upper Carboniferous
stem and the Scotch specimens from the Lower Carboniferous beds of
Burntisland suggests a probable specific difference. Dr Scott has recently
adopted the name Heterangium Lomaxi, proposed but not published by
Williamson, for the English type. Though in the following account the
species Heterangium Grievii is treated in the broader sense it should be
recognised that the geologically younger stem is worthy of specific
recognition; it is characterised, to quote Scott[215], by ‘the great distinctness
of the primary xylem strands, by their nearly exarch structure, with little
primary centrifugal wood, by the abundant secretory sacs of the stele, and
by the rather scattered leaves.’
discoverer of the specimens. In a later and more complete description
Williamson adopted Corda’s generic name on the ground of the close
resemblance of the Scotch stem to the Bohemian fragment Heterangium
paradoxum. In 1873[212] Williamson added new facts in regard to H. Grievii
and in 1890[213] he described a very closely allied type from the Lower Coal
Measures of Lancashire. Five years later his descriptions were considerably
extended and modified in the joint memoir with Dr Scott[214].
The great difference in age between the English Upper Carboniferous
stem and the Scotch specimens from the Lower Carboniferous beds of
Burntisland suggests a probable specific difference. Dr Scott has recently
adopted the name Heterangium Lomaxi, proposed but not published by
Williamson, for the English type. Though in the following account the
species Heterangium Grievii is treated in the broader sense it should be
recognised that the geologically younger stem is worthy of specific
recognition; it is characterised, to quote Scott[215], by ‘the great distinctness
of the primary xylem strands, by their nearly exarch structure, with little
primary centrifugal wood, by the abundant secretory sacs of the stele, and
by the rather scattered leaves.’
Page 110
Fig. 411. Heterangium Grievii. lt, a, b, c, leaf-traces; p, pericycle with
periderm; ph, phloem; x1, x2, primary and secondary xylem; px,
protoxylem; r, root; s, sclerous tissue.
Heterangium Grievii has a radially symmetrical stem bearing compound
leaves with decurrent petioles which give to the otherwise cylindrical axis
an angular outline as seen in transverse section (fig. 411, A). The
phyllotaxis appears to be ⅜. The stem rarely exceeds 1·5 cm. in diameter: in
the centre is a comparatively large stele consisting in young stems of
primary xylem and phloem, but in older stems these are separated by a
cylinder of secondary vascular tissue which in this species is always
narrower than in Lyginopteris oldhamia and, as Williamson pointed out,
periderm; ph, phloem; x1, x2, primary and secondary xylem; px,
protoxylem; r, root; s, sclerous tissue.
Heterangium Grievii has a radially symmetrical stem bearing compound
leaves with decurrent petioles which give to the otherwise cylindrical axis
an angular outline as seen in transverse section (fig. 411, A). The
phyllotaxis appears to be ⅜. The stem rarely exceeds 1·5 cm. in diameter: in
the centre is a comparatively large stele consisting in young stems of
primary xylem and phloem, but in older stems these are separated by a
cylinder of secondary vascular tissue which in this species is always
narrower than in Lyginopteris oldhamia and, as Williamson pointed out,
Page 111
often of unequal thickness on different radii. The medullated stele of
Lyginopteris is replaced by a solid xylem-cylinder consisting mainly of
groups of large tracheids, reaching ·3 mm. in diameter, with multiseriate
bordered pits (fig. 411, D) embedded in an anastomosing parenchymatous
tissue-system. In the stele reproduced in fig. 411, B, which with the
exception of a very narrow zone of secondary xylem, x2, consists entirely of
primary xylem, x1, the parenchyma is represented by a darker reticulum (cf.
fig. 415, B) dividing the metaxylem into islands as in Gleichenia. In the
peripheral portion of the xylem the tracheids are rather narrower and
arranged in more definite groups in many of which is a single strand of
narrow spiral elements (fig. 411, A′, px) close to the outer margin. These
peripheral primary bundles in which protoxylem is recognisable may be
described as leaf-traces of mesarch structure consisting of centripetal xylem
and, to a much less extent, of smaller centrifugal elements for the most part
with dense spiral bands in place of the multiseriate pits of the rest of the
metaxylem. The structure of these leaf-traces is practically identical with
that of the primary bundles of Lyginopteris. There is, however, a difference
to which attention is drawn by Williamson and Scott. While in Lyginopteris
in any transverse section the primary bundles in the stele are equal in
number to the leaf-traces in the pericycle and cortex, in Heterangium the
peripheral groups in the stele may be as many as twenty, a number
considerably in excess of the leaf-traces beyond the limits of the primary
xylem of the stele. It may be that the leaf-trace of each leaf, which joins the
stele at a distance of 6–10 internodes below its entrance into the cortex from
the leaf-stalk, may branch in its descent in the axial region, or some of the
primary groups of xylem may be confined to the axial region and
independent of the leaf-traces. Portions of the peripheral region of the stele
may be occupied by metaxylem groups without protoxylem and identical
with those which make up the bulk of the metaxylem.
Scott[216] has recently published a note in which he states that most of the
British Coal Measures Heterangiums were polydesmic. Two bundles, and
not a single strand as in the Scotch H. Grievii, leave the stele for each leaf,
and these divide into four, in some cases at least, before entering the petiole.
The secondary xylem is continuous at its inner edge with the outermost
primary tracheids (fig. 411, A′) and consists of rows of tracheids, 1–3
elements broad, alternating with numerous broad medullary rays of radially
Lyginopteris is replaced by a solid xylem-cylinder consisting mainly of
groups of large tracheids, reaching ·3 mm. in diameter, with multiseriate
bordered pits (fig. 411, D) embedded in an anastomosing parenchymatous
tissue-system. In the stele reproduced in fig. 411, B, which with the
exception of a very narrow zone of secondary xylem, x2, consists entirely of
primary xylem, x1, the parenchyma is represented by a darker reticulum (cf.
fig. 415, B) dividing the metaxylem into islands as in Gleichenia. In the
peripheral portion of the xylem the tracheids are rather narrower and
arranged in more definite groups in many of which is a single strand of
narrow spiral elements (fig. 411, A′, px) close to the outer margin. These
peripheral primary bundles in which protoxylem is recognisable may be
described as leaf-traces of mesarch structure consisting of centripetal xylem
and, to a much less extent, of smaller centrifugal elements for the most part
with dense spiral bands in place of the multiseriate pits of the rest of the
metaxylem. The structure of these leaf-traces is practically identical with
that of the primary bundles of Lyginopteris. There is, however, a difference
to which attention is drawn by Williamson and Scott. While in Lyginopteris
in any transverse section the primary bundles in the stele are equal in
number to the leaf-traces in the pericycle and cortex, in Heterangium the
peripheral groups in the stele may be as many as twenty, a number
considerably in excess of the leaf-traces beyond the limits of the primary
xylem of the stele. It may be that the leaf-trace of each leaf, which joins the
stele at a distance of 6–10 internodes below its entrance into the cortex from
the leaf-stalk, may branch in its descent in the axial region, or some of the
primary groups of xylem may be confined to the axial region and
independent of the leaf-traces. Portions of the peripheral region of the stele
may be occupied by metaxylem groups without protoxylem and identical
with those which make up the bulk of the metaxylem.
Scott[216] has recently published a note in which he states that most of the
British Coal Measures Heterangiums were polydesmic. Two bundles, and
not a single strand as in the Scotch H. Grievii, leave the stele for each leaf,
and these divide into four, in some cases at least, before entering the petiole.
The secondary xylem is continuous at its inner edge with the outermost
primary tracheids (fig. 411, A′) and consists of rows of tracheids, 1–3
elements broad, alternating with numerous broad medullary rays of radially
Page 112
elongated parenchyma. Beyond a typical cambium-zone the secondary
phloem consists of parenchyma and sieve-tubes bounded by crushed arcs of
primary phloem. Abutting on the phloem is a pericycle composed of several
layers of small parenchymatous cells (fig. 411, A, p) and in the outer layers
of this tissue a phellogen (fig. 411, C, p) and some periderm are usually
present though, as Williamson and Scott point out, the periderm is less
regular and narrower than in Lyginopteris. The inner cortex, composed of
short parenchymatous cells, is traversed by numerous narrow bands of dark,
thick-walled cells similar in the structure of the elements, though peculiar in
the horizontal elongation of the groups, to the sclerous nests in the pericycle
and pith of Lyginopteris. These characteristic bands are chiefly seen in the
oblique longitudinal section of a stem represented in fig. 412. In this
section, 25 mm. in length, the lighter band, p, is the pericycle and in it a few
obliquely cut leaf-traces are shown as dark patches. The horizontal bands
are similar in structure and shape to the diaphragms of thick cells in the pith
of Abies magnifica[217], and in both plants they probably serve as supports to
the softer parenchyma. There may be as many as 46 bands in a vertical
length of cortex of 1 inch (about 19 per centimetre). It was the occurrence
of precisely similar transverse lines on the carbonised impressions of the
rachis of Sphenopteris elegans that led Kidston[218] to suggest a connexion
between that species and the stem of Heterangium Grievii.
The outer cortex, consisting of alternate strands of parenchyma and
stereome similar to that of Lyginopteris, is much narrower and a less
conspicuous feature than in Heterangium; the stereome bands do not form
so regular a hypodermal network and extend much further vertically
without anastomosing. The epidermis has been described as a layer of fairly
thick cells showing in one case an appearance of a depressed stoma[219].
There are no secretory canals like those of Cycads but, as in Lyginopteris,
scattered cells with dark contents in the stem-tissues probably represent
secretory sacs.
The leaf-traces on leaving the stele pursue a very gradually ascending
course to the petiole; they retain their collateral structure in the pericycle
and cortex and have no secondary xylem, but become concentric as they
enter the base of a leaf.
phloem consists of parenchyma and sieve-tubes bounded by crushed arcs of
primary phloem. Abutting on the phloem is a pericycle composed of several
layers of small parenchymatous cells (fig. 411, A, p) and in the outer layers
of this tissue a phellogen (fig. 411, C, p) and some periderm are usually
present though, as Williamson and Scott point out, the periderm is less
regular and narrower than in Lyginopteris. The inner cortex, composed of
short parenchymatous cells, is traversed by numerous narrow bands of dark,
thick-walled cells similar in the structure of the elements, though peculiar in
the horizontal elongation of the groups, to the sclerous nests in the pericycle
and pith of Lyginopteris. These characteristic bands are chiefly seen in the
oblique longitudinal section of a stem represented in fig. 412. In this
section, 25 mm. in length, the lighter band, p, is the pericycle and in it a few
obliquely cut leaf-traces are shown as dark patches. The horizontal bands
are similar in structure and shape to the diaphragms of thick cells in the pith
of Abies magnifica[217], and in both plants they probably serve as supports to
the softer parenchyma. There may be as many as 46 bands in a vertical
length of cortex of 1 inch (about 19 per centimetre). It was the occurrence
of precisely similar transverse lines on the carbonised impressions of the
rachis of Sphenopteris elegans that led Kidston[218] to suggest a connexion
between that species and the stem of Heterangium Grievii.
The outer cortex, consisting of alternate strands of parenchyma and
stereome similar to that of Lyginopteris, is much narrower and a less
conspicuous feature than in Heterangium; the stereome bands do not form
so regular a hypodermal network and extend much further vertically
without anastomosing. The epidermis has been described as a layer of fairly
thick cells showing in one case an appearance of a depressed stoma[219].
There are no secretory canals like those of Cycads but, as in Lyginopteris,
scattered cells with dark contents in the stem-tissues probably represent
secretory sacs.
The leaf-traces on leaving the stele pursue a very gradually ascending
course to the petiole; they retain their collateral structure in the pericycle
and cortex and have no secondary xylem, but become concentric as they
enter the base of a leaf.
Page 113
Fig. 412. Heterangium Grievii. Oblique longitudinal section of stele and
part of cortex; p, pericycle. × 3. (Kidston Coll. 529.)
Before passing to the description of the leaves, the more striking features
in the stem may be summarised with reference to the diagrammatic sketches
shown in fig. 411. Fig. 411, A, represents a section of Heterangium Grievii
approximately 2 cm. in its maximum diameter; at the periphery of the
primary xylem, x1, and close to its outer margin are several protoxylem
groups, not shown in the drawing, each of which marks the position of a
mesarch trace. The zone of secondary xylem, x2, is interrupted by the exit of
leaf-traces and one of these is seen at a in fig. 415, A, separated from the
central primary xylem by a foliar gap filled with parenchyma. The pericycle
is shown at p in fig. 412 and its outer boundary at p in fig. 411, A. Beyond
the pericycle is the broad parenchymatous cortex with leaf-traces, lt, and
some sclerenchymatous patches, s. The vascular strand a is passing into the
base of a leaf-stalk. In the stem shown in fig. 411, B, 1·4 cm. × 7 mm., a
decurrent petiole is seen at the upper end with its single vascular strand, a,
and two sclerous nests; a similar though detached leaf-base occurs at the
opposite end of the long diameter. Other leaf-traces are seen at b and c.
part of cortex; p, pericycle. × 3. (Kidston Coll. 529.)
Before passing to the description of the leaves, the more striking features
in the stem may be summarised with reference to the diagrammatic sketches
shown in fig. 411. Fig. 411, A, represents a section of Heterangium Grievii
approximately 2 cm. in its maximum diameter; at the periphery of the
primary xylem, x1, and close to its outer margin are several protoxylem
groups, not shown in the drawing, each of which marks the position of a
mesarch trace. The zone of secondary xylem, x2, is interrupted by the exit of
leaf-traces and one of these is seen at a in fig. 415, A, separated from the
central primary xylem by a foliar gap filled with parenchyma. The pericycle
is shown at p in fig. 412 and its outer boundary at p in fig. 411, A. Beyond
the pericycle is the broad parenchymatous cortex with leaf-traces, lt, and
some sclerenchymatous patches, s. The vascular strand a is passing into the
base of a leaf-stalk. In the stem shown in fig. 411, B, 1·4 cm. × 7 mm., a
decurrent petiole is seen at the upper end with its single vascular strand, a,
and two sclerous nests; a similar though detached leaf-base occurs at the
opposite end of the long diameter. Other leaf-traces are seen at b and c.
Page 114
From the left-hand side of the stele a curved strand of tracheids is passing
out to supply a root, r.
ii. Root.
Adventitious roots of endogenous origin are occasionally met with in
Heterangium stems, but we have less information as to their anatomy than
in the case of Lyginopteris. In a specimen of Heterangium Lomaxi figured
by Williamson and Scott[220] three roots are seen in a vertical series growing
outwards through the cortex of a stem. The roots agree generally with those
of Lyginopteris but the outermost cortical layers possess no special features.
iii. Leaf.
The large compound fronds long known as Sphenopteris elegans were
recognised by Kidston as the leaves of Heterangium by the closely arranged
transverse striae or narrow ribs on the rachis and pinnae which are the
expression on the carbonised impressions of the horizontal plates of
sclerous tissue in the petrified stems and petioles of Heterangium. The
dichotomously branched fronds are included by Stur in his genus
Diplotmema and that author figures several typical examples in his ‘Culm
Flora’[221]. Fig. 413, A, shows a forked axis with the bases of more slender
branches and the characteristic transverse bands and in fig. 413, B, part of a
pinna is reproduced. In general appearance, except in the bifurcating
pinnae, the fronds resemble those of Davallia tenuifolia with which
Brongniart compared the Palaeozoic species. There is little doubt that
Sphenopteris dissecta and some other species were also borne on
Heterangium stems. The rachis and petioles differ from those of
Lyginopteris fronds in the absence of emergences (cf. fig. 404, E). The
petioles (fig. 411, B, a) have a single concentric vascular bundle with
internal protoxylem.
out to supply a root, r.
ii. Root.
Adventitious roots of endogenous origin are occasionally met with in
Heterangium stems, but we have less information as to their anatomy than
in the case of Lyginopteris. In a specimen of Heterangium Lomaxi figured
by Williamson and Scott[220] three roots are seen in a vertical series growing
outwards through the cortex of a stem. The roots agree generally with those
of Lyginopteris but the outermost cortical layers possess no special features.
iii. Leaf.
The large compound fronds long known as Sphenopteris elegans were
recognised by Kidston as the leaves of Heterangium by the closely arranged
transverse striae or narrow ribs on the rachis and pinnae which are the
expression on the carbonised impressions of the horizontal plates of
sclerous tissue in the petrified stems and petioles of Heterangium. The
dichotomously branched fronds are included by Stur in his genus
Diplotmema and that author figures several typical examples in his ‘Culm
Flora’[221]. Fig. 413, A, shows a forked axis with the bases of more slender
branches and the characteristic transverse bands and in fig. 413, B, part of a
pinna is reproduced. In general appearance, except in the bifurcating
pinnae, the fronds resemble those of Davallia tenuifolia with which
Brongniart compared the Palaeozoic species. There is little doubt that
Sphenopteris dissecta and some other species were also borne on
Heterangium stems. The rachis and petioles differ from those of
Lyginopteris fronds in the absence of emergences (cf. fig. 404, E). The
petioles (fig. 411, B, a) have a single concentric vascular bundle with
internal protoxylem.
Page 115
Fig. 413. Sphenopteris (Diplotmema) elegans. A. Forked rachis with
bases of lateral branches (Kidston Coll.); B, pinna. (After Stur.)
iv. Reproductive organs.
As yet no satisfactory evidence has been published with regard to the
nature of the microsporangia but in all probability these were constructed
on the same plan as those of Lyginopteris. There is a strong prima facie case
for assigning the seed Sphaerostoma to Heterangium: absolute proof of
organic connexion is still lacking though Dr Benson’s recent account of the
seeds associated with Heterangium Grievii almost amounts to
demonstration of continuity between vegetative organs and seeds.
bases of lateral branches (Kidston Coll.); B, pinna. (After Stur.)
iv. Reproductive organs.
As yet no satisfactory evidence has been published with regard to the
nature of the microsporangia but in all probability these were constructed
on the same plan as those of Lyginopteris. There is a strong prima facie case
for assigning the seed Sphaerostoma to Heterangium: absolute proof of
organic connexion is still lacking though Dr Benson’s recent account of the
seeds associated with Heterangium Grievii almost amounts to
demonstration of continuity between vegetative organs and seeds.
Page 116
Fig. 414. Sphaerostoma ovale. A. Longitudinal section showing the
cupule, c, integument, e, f, with vascular bundle, v, the upper part
of the nucellus, n, and megaspore, m; a, archegonia. B. Transverse
section through the roof of the pollen-chamber, pc, and the summit
of the nucellus, n. (After Benson.)
Sphaerostoma ovale (Williamson).
In 1877 Williamson described some detached petrified seeds from the
Lower Carboniferous rocks of Fifeshire, Scotland, as Conostoma ovale and
C. intermedium. Dr Benson’s investigation[222] of these two forms leads her
to confirm Williamson’s doubts as to the validity of a specific separation
and she assigns the single type to the new genus Sphaerostoma. The seeds
are always associated with the vegetative organs of Heterangium Grievii. In
1909 Oliver[223] expressed the opinion that the Burntisland species of
Conostoma (= Sphaerostoma) is probably the seed of Heterangium. The
seed consists of a central body representing the nucellus, an inner
integument, and an enveloping cupule or outer integument: most specimens
have lost the cupule and in this condition they are 3·5 mm. long with a
maximum breadth of 2·2 mm. In the middle the seed is circular in
cupule, c, integument, e, f, with vascular bundle, v, the upper part
of the nucellus, n, and megaspore, m; a, archegonia. B. Transverse
section through the roof of the pollen-chamber, pc, and the summit
of the nucellus, n. (After Benson.)
Sphaerostoma ovale (Williamson).
In 1877 Williamson described some detached petrified seeds from the
Lower Carboniferous rocks of Fifeshire, Scotland, as Conostoma ovale and
C. intermedium. Dr Benson’s investigation[222] of these two forms leads her
to confirm Williamson’s doubts as to the validity of a specific separation
and she assigns the single type to the new genus Sphaerostoma. The seeds
are always associated with the vegetative organs of Heterangium Grievii. In
1909 Oliver[223] expressed the opinion that the Burntisland species of
Conostoma (= Sphaerostoma) is probably the seed of Heterangium. The
seed consists of a central body representing the nucellus, an inner
integument, and an enveloping cupule or outer integument: most specimens
have lost the cupule and in this condition they are 3·5 mm. long with a
maximum breadth of 2·2 mm. In the middle the seed is circular in
Page 117
transverse section and octagonal near the base and apex. The free apical
part of the integument forms a frill (canopy) round the micropyle and
extends beyond the nucellar apex which consists of a relatively flat plinth
surmounted by a central dome or lagenostome (fig. 414). The lagenostome
is surrounded by an annular pollen-chamber on to the lower surface of
which abuts the large embryo-sac, and remains of archegonia were noticed
below the pollen-chamber. The roof of the chamber in the young state
consists of a layer of thin-walled cells extending across the flattened apex
of the nucellus, n, but as the pollen-chamber becomes differentiated from
the nucellar tissue by the disorganisation of the zone of cells its roof-cells
thicken their vertical walls and assume the structure of a multiseriate
annulus, which acts as a mechanism for opening the pollen-chamber by a
circular dehiscence in such a way that the edge of the ruptured roof of the
pollen-chamber slightly overlaps the periphery of the central column of
nucellar tissue after it has returned to its original position subsequent to the
entrance of the microspores. The micropylar region is surrounded by eight
lobes of the integument and each is characterised by a crest of radially
elongated cells, fig. 414, f, especially prominent on the outer side. External
to this is the slightly longer cupular sheath (fig. 414, c) which may also
have been lobed. The surface of the integument below the terminal crests
consists of a layer of cells with small papillae which eventually ruptured
and discharged mucilage. Both integuments have a vascular supply, that of
the inner integument being represented by eight vascular bundles, some of
which were found to have mesarch xylem, given off from the single strand
in the pedicel. Fig. 414 shows the apical region of a seed of Sphaerostoma:
the flat-topped nucellar cap, n, is surrounded by the annular pollen-
chamber, pc, below which are indicated the archegonia: the wall of the
megaspore (embryo-sac) is seen at m and external to this vascular bundles,
v, run up the inner portion of the integument accompanied by some large
cells (aqueous tissue). The elongated epidermal cells at the apices of the
lobes of the integument form the frill, f, and at a lower level the cells of the
same layer are much smaller and papillate (e): the outer integument, c,
forms the so-called cupule. The transverse section shown in fig. 414, B, is
taken at the level of the roof of the pollen-chamber and of the nucellar cap;
it illustrates the contrast between the ‘multiseriate annulus’ and the central
column of small parenchyma.
part of the integument forms a frill (canopy) round the micropyle and
extends beyond the nucellar apex which consists of a relatively flat plinth
surmounted by a central dome or lagenostome (fig. 414). The lagenostome
is surrounded by an annular pollen-chamber on to the lower surface of
which abuts the large embryo-sac, and remains of archegonia were noticed
below the pollen-chamber. The roof of the chamber in the young state
consists of a layer of thin-walled cells extending across the flattened apex
of the nucellus, n, but as the pollen-chamber becomes differentiated from
the nucellar tissue by the disorganisation of the zone of cells its roof-cells
thicken their vertical walls and assume the structure of a multiseriate
annulus, which acts as a mechanism for opening the pollen-chamber by a
circular dehiscence in such a way that the edge of the ruptured roof of the
pollen-chamber slightly overlaps the periphery of the central column of
nucellar tissue after it has returned to its original position subsequent to the
entrance of the microspores. The micropylar region is surrounded by eight
lobes of the integument and each is characterised by a crest of radially
elongated cells, fig. 414, f, especially prominent on the outer side. External
to this is the slightly longer cupular sheath (fig. 414, c) which may also
have been lobed. The surface of the integument below the terminal crests
consists of a layer of cells with small papillae which eventually ruptured
and discharged mucilage. Both integuments have a vascular supply, that of
the inner integument being represented by eight vascular bundles, some of
which were found to have mesarch xylem, given off from the single strand
in the pedicel. Fig. 414 shows the apical region of a seed of Sphaerostoma:
the flat-topped nucellar cap, n, is surrounded by the annular pollen-
chamber, pc, below which are indicated the archegonia: the wall of the
megaspore (embryo-sac) is seen at m and external to this vascular bundles,
v, run up the inner portion of the integument accompanied by some large
cells (aqueous tissue). The elongated epidermal cells at the apices of the
lobes of the integument form the frill, f, and at a lower level the cells of the
same layer are much smaller and papillate (e): the outer integument, c,
forms the so-called cupule. The transverse section shown in fig. 414, B, is
taken at the level of the roof of the pollen-chamber and of the nucellar cap;
it illustrates the contrast between the ‘multiseriate annulus’ and the central
column of small parenchyma.
Page 118
Sphaerostoma differs from Lagenostoma in the whorl of crests around
the micropyle, in the nearly hemispherical form of the lagenostome and in
the relatively wider pollen-chamber with its peculiar form of dehiscence.
Miss Benson, while regarding Sphaerostoma as similar to Lagenostoma in
general plan, believes the distinguishing features of the former to be such as
are consistent with a more primitive form.
An important argument in support of connecting this seed with
Heterangium is derived from the juxtaposition of some seeds and portions
of Heterangium petioles, a juxtaposition that is believed to demonstrate
original continuity.
Grand’Eury[224] has recorded the association of two species of leaves,
Sphenopteris elegans and S. dissecta, with small seeds compared by him
with Lagenostoma. In the absence of petrified specimens it would be
practically impossible to distinguish between Lagenostoma and Conostoma
or Sphaerostoma.
Carpentier[225] has described some impressions from French Westphalian
beds as Conostoma and he records cupules without seeds on fronds of
Sphenopteris obtusifolia which he speaks of as having transverse striations
like those of Heterangium. Dr Kidston pointed out to me that the surface-
features of the Sphenopteris rachis are probably due to ramental scales and
not to the presence of horizontal sclerous bands. Carpentier’s seeds may be
compared with Lagenospermum Sinclairi.
Heterangium tiliaeoides Williamson, Phil. Trans. R. Soc. Vol. 178, p. 289.
This species, founded by Williamson on material from the Lower Coal
Measures of Halifax, Yorkshire, while agreeing in the structure of the
primary stele and in the general features of the cortex with the older
Heterangium Grievii, is clearly distinguished by certain well-marked
characters. Sclerous groups occur in the inner cortex as in H. Grievii but
they are present also in the pericycle. The peripheral leaf-traces in the stele
show the mesarch structure rather more distinctly than in H. Grievii, and the
secondary xylem, which forms a much broader cylinder than in the Scotch
type, is divided by broad medullary rays into characteristic cuneate masses
each of which rests at its base on the centrifugal tracheids of a leaf-trace
strand of xylem (fig. 415, B). The most striking distinctive feature is
the micropyle, in the nearly hemispherical form of the lagenostome and in
the relatively wider pollen-chamber with its peculiar form of dehiscence.
Miss Benson, while regarding Sphaerostoma as similar to Lagenostoma in
general plan, believes the distinguishing features of the former to be such as
are consistent with a more primitive form.
An important argument in support of connecting this seed with
Heterangium is derived from the juxtaposition of some seeds and portions
of Heterangium petioles, a juxtaposition that is believed to demonstrate
original continuity.
Grand’Eury[224] has recorded the association of two species of leaves,
Sphenopteris elegans and S. dissecta, with small seeds compared by him
with Lagenostoma. In the absence of petrified specimens it would be
practically impossible to distinguish between Lagenostoma and Conostoma
or Sphaerostoma.
Carpentier[225] has described some impressions from French Westphalian
beds as Conostoma and he records cupules without seeds on fronds of
Sphenopteris obtusifolia which he speaks of as having transverse striations
like those of Heterangium. Dr Kidston pointed out to me that the surface-
features of the Sphenopteris rachis are probably due to ramental scales and
not to the presence of horizontal sclerous bands. Carpentier’s seeds may be
compared with Lagenospermum Sinclairi.
Heterangium tiliaeoides Williamson, Phil. Trans. R. Soc. Vol. 178, p. 289.
This species, founded by Williamson on material from the Lower Coal
Measures of Halifax, Yorkshire, while agreeing in the structure of the
primary stele and in the general features of the cortex with the older
Heterangium Grievii, is clearly distinguished by certain well-marked
characters. Sclerous groups occur in the inner cortex as in H. Grievii but
they are present also in the pericycle. The peripheral leaf-traces in the stele
show the mesarch structure rather more distinctly than in H. Grievii, and the
secondary xylem, which forms a much broader cylinder than in the Scotch
type, is divided by broad medullary rays into characteristic cuneate masses
each of which rests at its base on the centrifugal tracheids of a leaf-trace
strand of xylem (fig. 415, B). The most striking distinctive feature is
Page 119
afforded by the secondary phloem, which is often preserved in wonderful
perfection; this is unusually thick and owing to the tangential expansion of
the principal medullary rays the secondary phloem is divided into separate
masses which decrease in breadth towards the external arcs of primary
phloem. The triangular form of the phloem rays, composed of tangentially
stretched parenchyma, suggested the specific name tiliaeoides on account
of their striking resemblance to the rays of Tilia. The leaf-traces are nearly
always in pairs as they pass out through the cortex; they subsequently
divide and appear as four vascular strands in the petiole. The portion of
stem reproduced in fig. 415, B, 8 mm. broad, shows clearly the separation
of the secondary xylem and phloem into wedge-shaped groups: in each
group there are several narrow medullary rays. The extrastelar tissues are
represented by a few fragments only. Several layers of crushed periderm
occur in the pericyclic region but the more external tissues have been
almost completely exfoliated[226].
perfection; this is unusually thick and owing to the tangential expansion of
the principal medullary rays the secondary phloem is divided into separate
masses which decrease in breadth towards the external arcs of primary
phloem. The triangular form of the phloem rays, composed of tangentially
stretched parenchyma, suggested the specific name tiliaeoides on account
of their striking resemblance to the rays of Tilia. The leaf-traces are nearly
always in pairs as they pass out through the cortex; they subsequently
divide and appear as four vascular strands in the petiole. The portion of
stem reproduced in fig. 415, B, 8 mm. broad, shows clearly the separation
of the secondary xylem and phloem into wedge-shaped groups: in each
group there are several narrow medullary rays. The extrastelar tissues are
represented by a few fragments only. Several layers of crushed periderm
occur in the pericyclic region but the more external tissues have been
almost completely exfoliated[226].
Page 120
Page 121
Fig. 415. A, B, Heterangium. A, H. Grievii, a, leaf-traces. B, H.
tiliaeoides. C, root of Lyginopteris.
(A, B, Kidston Coll., 529, 294; C, Williamson Coll., 1631.)
Reference has already been made to Heterangium Lomaxi, the English
type originally included by Williamson in Heterangium Grievii. The
provisional species Heterangium cylindricum Williamson and Scott[227]
differs, as Scott says, in no important respect from H. Lomaxi and should
not be retained. A new species, H. minimum Scott[228], has been founded on
a very small stem from the Coal Measures of Dulesgate in which the leaf-
traces leave the stele as single bundles as in the Scotch H. Grievii.
The French species Heterangium Duchartrei[229] Ren. from Permian rocks
was originally referred by Renault to the genus Poroxylon: it is represented
by little more than the xylem of the stele and bears a close resemblance to
H. tiliaeoides. Heterangium punctatum Ren. and H. Renaulti[230] (Brongn.)
also from the Permian of France were originally placed in the genus
Lycopodium and afterwards recognised as stems of Heterangium. A fourth
French Permian species, H. bibractense[231], is peculiar in the possession of
a very small primary stele encircled by deep wedges of secondary xylem,
but without more information it is impossible to speak with confidence as to
its systematic position. Kubart[232] has recently published brief descriptions
of some stems from the Ostrauer coal-basin in Moravia all of which he
regards as specifically distinct from the English types. In Heterangium Sturi
the primary xylem is almost exarch and the peripheral xylem groups are not
very clearly defined: in H. alatum, so called from the presence of lateral
wings on the petioles, the leaf-trace strands are more sharply differentiated
from the rest of the stele. H. polystichum is a similar type, and H. Andrei,
with a relatively larger amount of parenchyma in the stele and thicker stems
forms an additional link between Heterangium and Lyginopteris[233]. Prof.
Johnson[234] has described a species of Heterangium, H. hibernicum, from
Upper Devonian and Lower Carboniferous beds in Co. Cork, Ireland, based
on some impressions of frond fragments without any pinnules. The
occurrence of numerous transverse striae on the rachis and lateral branches
suggests comparison with Heterangium fronds, but an examination of the
specimens led me to suspect that some at least of the striae are cracks and
not original features. The presence of spur-like appendages from the lower
surface of the pinnae near their origin from the rachis is recorded as a
tiliaeoides. C, root of Lyginopteris.
(A, B, Kidston Coll., 529, 294; C, Williamson Coll., 1631.)
Reference has already been made to Heterangium Lomaxi, the English
type originally included by Williamson in Heterangium Grievii. The
provisional species Heterangium cylindricum Williamson and Scott[227]
differs, as Scott says, in no important respect from H. Lomaxi and should
not be retained. A new species, H. minimum Scott[228], has been founded on
a very small stem from the Coal Measures of Dulesgate in which the leaf-
traces leave the stele as single bundles as in the Scotch H. Grievii.
The French species Heterangium Duchartrei[229] Ren. from Permian rocks
was originally referred by Renault to the genus Poroxylon: it is represented
by little more than the xylem of the stele and bears a close resemblance to
H. tiliaeoides. Heterangium punctatum Ren. and H. Renaulti[230] (Brongn.)
also from the Permian of France were originally placed in the genus
Lycopodium and afterwards recognised as stems of Heterangium. A fourth
French Permian species, H. bibractense[231], is peculiar in the possession of
a very small primary stele encircled by deep wedges of secondary xylem,
but without more information it is impossible to speak with confidence as to
its systematic position. Kubart[232] has recently published brief descriptions
of some stems from the Ostrauer coal-basin in Moravia all of which he
regards as specifically distinct from the English types. In Heterangium Sturi
the primary xylem is almost exarch and the peripheral xylem groups are not
very clearly defined: in H. alatum, so called from the presence of lateral
wings on the petioles, the leaf-trace strands are more sharply differentiated
from the rest of the stele. H. polystichum is a similar type, and H. Andrei,
with a relatively larger amount of parenchyma in the stele and thicker stems
forms an additional link between Heterangium and Lyginopteris[233]. Prof.
Johnson[234] has described a species of Heterangium, H. hibernicum, from
Upper Devonian and Lower Carboniferous beds in Co. Cork, Ireland, based
on some impressions of frond fragments without any pinnules. The
occurrence of numerous transverse striae on the rachis and lateral branches
suggests comparison with Heterangium fronds, but an examination of the
specimens led me to suspect that some at least of the striae are cracks and
not original features. The presence of spur-like appendages from the lower
surface of the pinnae near their origin from the rachis is recorded as a
Page 122
peculiar character, and some obscure oval bodies, the nature of which is
extremely doubtful, are considered to be seeds. The imperfection of the
material hardly justifies the institution of a new species of Heterangium.
Heterangium ranges from the Lower Carboniferous to the Permian strata
and is thus older than Lyginopteris which in the form of petrified stems is
not recorded from the Lower beds of the Carboniferous system.
Heterangium has been described as having a ‘great preponderance of fern-
like characters,’ but having regard to the resemblance of the primary xylem
of the latter to that of the Osmundaceae it would seem doubtful whether in
their relation to the Ferns there is any important difference. Heterangium
may safely be spoken of as the more primitive genus. The polydesmic
character of the petioles of most species is particularly interesting as it
brings the genus nearer to the Medulloseae and to Rhetinangium[235].
extremely doubtful, are considered to be seeds. The imperfection of the
material hardly justifies the institution of a new species of Heterangium.
Heterangium ranges from the Lower Carboniferous to the Permian strata
and is thus older than Lyginopteris which in the form of petrified stems is
not recorded from the Lower beds of the Carboniferous system.
Heterangium has been described as having a ‘great preponderance of fern-
like characters,’ but having regard to the resemblance of the primary xylem
of the latter to that of the Osmundaceae it would seem doubtful whether in
their relation to the Ferns there is any important difference. Heterangium
may safely be spoken of as the more primitive genus. The polydesmic
character of the petioles of most species is particularly interesting as it
brings the genus nearer to the Medulloseae and to Rhetinangium[235].
Page 123
Page 124
CHAPTER XXX.
II. MEDULLOSEAE.
The term Medulloseae was first employed by Goeppert and Stenzel[236]
for a family of Palaeozoic plants that appears to have reached its maximum
development in the Permian period: the oldest representatives so far
discovered are of Upper Carboniferous age. Our knowledge of the family is
chiefly derived from a study of the anatomical characters of stems, and it is
therefore on this basis that any grouping of genera or species should be
attempted. Although there is little information with regard to the
reproductive organs of Medullosa, the type-genus, it is certain that the
Medulloseae are Pteridosperms differing from members of that group
included in the Lyginopterideae in the presence of more than one stele in
the stem, in the habit of the fronds, and in the structure of the rachis, as also
in the structure of the seeds, though these organs bear a fairly close
resemblance to the seeds of Lyginopteris and Heterangium. The fronds of
the Lyginopterideae are of the Sphenopteris type while in the case of such
species of Medullosa as afford evidence of connexion between stems and
leaves the latter have the characters of Neuropteris, Alethopteris,
Odontopteris, Linopteris, and other form-genera usually included in the
Neuropterideae. Dr Lotsy[237] speaks of Lyginopteris and Heterangium as
members of the Sphenopteridophylla and assigns species of Medullosa
either to the Neuropteridophylla or to the Pecopteridophylla, the latter
subdivision including species with fronds of the Alethopteris type. There is,
however, little doubt that other forms of leaves, such as Odontopteris and
possibly Taeniopteris, were borne on Medullosan stems. It is undesirable
except in the absence of more trustworthy criteria to make use of so protean
a feature as leaf-form as a basis of classification. The name Neuropterideae
has been frequently employed for Pteridosperms other than the
Lyginopterideae on the ground that the foliage of Medullosa is represented
by species assigned to form-genera included in the Neuropterideae. It is,
however, preferable to restrict the family-name Neuropterideae to fronds
and to speak of the second family of Pteridosperms as the Medulloseae,
including the genera Medullosa, Sutcliffia, and Rhexoxylon.
II. MEDULLOSEAE.
The term Medulloseae was first employed by Goeppert and Stenzel[236]
for a family of Palaeozoic plants that appears to have reached its maximum
development in the Permian period: the oldest representatives so far
discovered are of Upper Carboniferous age. Our knowledge of the family is
chiefly derived from a study of the anatomical characters of stems, and it is
therefore on this basis that any grouping of genera or species should be
attempted. Although there is little information with regard to the
reproductive organs of Medullosa, the type-genus, it is certain that the
Medulloseae are Pteridosperms differing from members of that group
included in the Lyginopterideae in the presence of more than one stele in
the stem, in the habit of the fronds, and in the structure of the rachis, as also
in the structure of the seeds, though these organs bear a fairly close
resemblance to the seeds of Lyginopteris and Heterangium. The fronds of
the Lyginopterideae are of the Sphenopteris type while in the case of such
species of Medullosa as afford evidence of connexion between stems and
leaves the latter have the characters of Neuropteris, Alethopteris,
Odontopteris, Linopteris, and other form-genera usually included in the
Neuropterideae. Dr Lotsy[237] speaks of Lyginopteris and Heterangium as
members of the Sphenopteridophylla and assigns species of Medullosa
either to the Neuropteridophylla or to the Pecopteridophylla, the latter
subdivision including species with fronds of the Alethopteris type. There is,
however, little doubt that other forms of leaves, such as Odontopteris and
possibly Taeniopteris, were borne on Medullosan stems. It is undesirable
except in the absence of more trustworthy criteria to make use of so protean
a feature as leaf-form as a basis of classification. The name Neuropterideae
has been frequently employed for Pteridosperms other than the
Lyginopterideae on the ground that the foliage of Medullosa is represented
by species assigned to form-genera included in the Neuropterideae. It is,
however, preferable to restrict the family-name Neuropterideae to fronds
and to speak of the second family of Pteridosperms as the Medulloseae,
including the genera Medullosa, Sutcliffia, and Rhexoxylon.
Page 125
MEDULLOSA.
Some species of Medullosa probably resembled in habit Angiopteris
evecta and the larger Marattias; they had short and relatively thick stems
clothed with the large decurrent bases of long compound fronds
superficially like those of some recent Ferns and the leaves of the Cycad
Bowenia. It is probable that, as Zeiller[238] has pointed out, the fronds of
Medullosa and of other Pteridosperms had a greater tendency than those of
true Ferns to a dichotomy of the rachis. In other types the stems reached a
considerable length and leaves and branches were separated by several feet
of bare stem. The large size of the leaf-stalks in proportion to the diameter
of the stem as shown by such species as Medullosa anglica and M.
Leuckarti (fig. 416) suggests either a short and thick main axis or, in the
case of long stems bearing scattered leaves, a plant that supported itself
partially at least by a habit of growth comparable with that of tropical
Aroids or other lianes. While Medullosa anglica with its contiguous leaf-
bases affords an example of the first type, the occurrence of stems of a
Permian species, M. stellata, 3½ metres long without branches or leaf-scars,
suggests the habit of a liane; similarly a specimen of Medullosa Leuckarti
in the Chemnitz Museum bearing a few spreading petioles but little
narrower than the stem and given off at a wide angle would seem to favour
the view that some species were ill adapted to be mechanically self-
supporting plants. The longest piece of stem that has come under my notice
is a specimen of M. stellata in the Chemnitz Museum reaching a length of
nearly 8 metres: some species attained a diameter of about 50 centimetres.
Medullosa is always polystelic: the plan of the vascular system varies
considerably as regards both the number and form of the steles, but there is
a uniform type of structure within the limits of each stele that recalls the
single stele of Heterangium. The steles consist of a central region composed
of primary xylem, originally surrounded by phloem, which in its mesarch or
exarch structure agrees with the vascular tissue of some species of
Gleichenia or Lygodium. To this central region a cambium added secondary
xylem and phloem either in the form of a cylinder of uniform breadth, or
more frequently the centrifugally developed xylem exceeded in amount the
secondary conducting tissue added to the inner side of the primary region.
Apart from anatomical details a Medullosan stem with its several steles,
each with secondary tissue, embedded in parenchymatous ground-tissue
Some species of Medullosa probably resembled in habit Angiopteris
evecta and the larger Marattias; they had short and relatively thick stems
clothed with the large decurrent bases of long compound fronds
superficially like those of some recent Ferns and the leaves of the Cycad
Bowenia. It is probable that, as Zeiller[238] has pointed out, the fronds of
Medullosa and of other Pteridosperms had a greater tendency than those of
true Ferns to a dichotomy of the rachis. In other types the stems reached a
considerable length and leaves and branches were separated by several feet
of bare stem. The large size of the leaf-stalks in proportion to the diameter
of the stem as shown by such species as Medullosa anglica and M.
Leuckarti (fig. 416) suggests either a short and thick main axis or, in the
case of long stems bearing scattered leaves, a plant that supported itself
partially at least by a habit of growth comparable with that of tropical
Aroids or other lianes. While Medullosa anglica with its contiguous leaf-
bases affords an example of the first type, the occurrence of stems of a
Permian species, M. stellata, 3½ metres long without branches or leaf-scars,
suggests the habit of a liane; similarly a specimen of Medullosa Leuckarti
in the Chemnitz Museum bearing a few spreading petioles but little
narrower than the stem and given off at a wide angle would seem to favour
the view that some species were ill adapted to be mechanically self-
supporting plants. The longest piece of stem that has come under my notice
is a specimen of M. stellata in the Chemnitz Museum reaching a length of
nearly 8 metres: some species attained a diameter of about 50 centimetres.
Medullosa is always polystelic: the plan of the vascular system varies
considerably as regards both the number and form of the steles, but there is
a uniform type of structure within the limits of each stele that recalls the
single stele of Heterangium. The steles consist of a central region composed
of primary xylem, originally surrounded by phloem, which in its mesarch or
exarch structure agrees with the vascular tissue of some species of
Gleichenia or Lygodium. To this central region a cambium added secondary
xylem and phloem either in the form of a cylinder of uniform breadth, or
more frequently the centrifugally developed xylem exceeded in amount the
secondary conducting tissue added to the inner side of the primary region.
Apart from anatomical details a Medullosan stem with its several steles,
each with secondary tissue, embedded in parenchymatous ground-tissue
Page 126
resembles the stems of some Dicotyledonous climbers such as Thinouia
scandens, species of Serjania and Paullinia[239].
Anatomically the main features of the stelar system of Medullosa,
neglecting the secondary xylem and phloem, are in closer agreement with
the stems of Ferns than with those of any other plants. It has been shown
that the genus Heterangium bears a close resemblance to Gleichenia in the
structure of the primary stele (fig. 418, C): one of the oldest types of
Medullosa, M. anglica, may be described as a Heterangium with three
steles and may be compared with a dictyostelic Fern in which the irregular
vascular framework is made up of three main strands. In certain types of
Medullosa (fig. 416) the ground-plan of the vascular system recalls that of a
solenostelic Fern, while in others the greater complexity suggests
comparison with such Ferns as Matonia, Angiopteris, Psaronius, or
Cyathea; ‘it is as though Nature were at the Carboniferous moment in the
midst of a series of amazing engineering experiments, most of which were
either buried deep in Palaeozoic oblivion, or permitted to survive only as
vestigial relics and atavistic ghosts’[240]. Though many Medullosae resemble
Ferns there is an important difference between the two groups in the origin
of the various plans of Medullosan stelar systems: in Ferns the leaf is the
determining factor in the evolution of stelar arrangement, while in
Medullosa the occasional interruption of a solenostele or the development
of an apparently complex dictyostele are features independent of the leaf
and leaf-traces. In the structure of the secondary xylem and phloem and in
root-structure Medullosa agrees with recent Cycads. The genus is in short a
generalised type with filicinean and cycadean affinities. In the possession of
seeds borne on modified pinnae of compound fronds, Medullosa resembles
both Cycas and the Lyginopterideae. The seeds exhibit a fairly close
agreement with those of Lyginopteris, Heterangium and recent Cycads, but
they appear to have advanced further towards the cycadean type than is the
case with the closely related seeds of the Lyginopterideae. The
microsporophylls are very imperfectly known but they were undoubtedly
much less advanced and more fern-like than the megasporophylls.
The genus Medullosa is recorded from the Permian strata of Saxony,
France, and Bohemia[241]; also from the Coal Measures of England, and the
discovery of petrified petioles of Myeloxylon, the type borne on Medullosan
scandens, species of Serjania and Paullinia[239].
Anatomically the main features of the stelar system of Medullosa,
neglecting the secondary xylem and phloem, are in closer agreement with
the stems of Ferns than with those of any other plants. It has been shown
that the genus Heterangium bears a close resemblance to Gleichenia in the
structure of the primary stele (fig. 418, C): one of the oldest types of
Medullosa, M. anglica, may be described as a Heterangium with three
steles and may be compared with a dictyostelic Fern in which the irregular
vascular framework is made up of three main strands. In certain types of
Medullosa (fig. 416) the ground-plan of the vascular system recalls that of a
solenostelic Fern, while in others the greater complexity suggests
comparison with such Ferns as Matonia, Angiopteris, Psaronius, or
Cyathea; ‘it is as though Nature were at the Carboniferous moment in the
midst of a series of amazing engineering experiments, most of which were
either buried deep in Palaeozoic oblivion, or permitted to survive only as
vestigial relics and atavistic ghosts’[240]. Though many Medullosae resemble
Ferns there is an important difference between the two groups in the origin
of the various plans of Medullosan stelar systems: in Ferns the leaf is the
determining factor in the evolution of stelar arrangement, while in
Medullosa the occasional interruption of a solenostele or the development
of an apparently complex dictyostele are features independent of the leaf
and leaf-traces. In the structure of the secondary xylem and phloem and in
root-structure Medullosa agrees with recent Cycads. The genus is in short a
generalised type with filicinean and cycadean affinities. In the possession of
seeds borne on modified pinnae of compound fronds, Medullosa resembles
both Cycas and the Lyginopterideae. The seeds exhibit a fairly close
agreement with those of Lyginopteris, Heterangium and recent Cycads, but
they appear to have advanced further towards the cycadean type than is the
case with the closely related seeds of the Lyginopterideae. The
microsporophylls are very imperfectly known but they were undoubtedly
much less advanced and more fern-like than the megasporophylls.
The genus Medullosa is recorded from the Permian strata of Saxony,
France, and Bohemia[241]; also from the Coal Measures of England, and the
discovery of petrified petioles of Myeloxylon, the type borne on Medullosan
Page 127
stems in European species, may be taken as evidence of the existence of the
genus in North America during the Carboniferous period[242].
The name Medullosa was applied by Cotta[243] to three types, Medullosa
elegans, M. stellata, and M. porosa, from the Rothliegende of the Chemnitz
district. The first of these was recognised by Brongniart[244] as a distinct
genus for which he proposed the designation Myeloxylon and this was
afterwards identified by Renault, Williamson, and other palaeobotanists as a
petiole and not a stem. Further reference is made to Myeloxylon on a later
page. Cotta spoke of Medullosa as the most puzzling of the genera dealt
with in his ‘Dendrolithen,’ and in spite of the many additions to our
knowledge the position of this Palaeozoic genus is still a fertile source of
speculation. The generic designation Medullosa is applied to stems, with or
without petioles; petioles or rachises of fronds that frequently occur apart
from stems are referred to the genus Myeloxylon. The leaves of Medullosa
include several well-known species of Carboniferous and Permian genera
such as Alethopteris, Neuropteris and others that have in recent years been
transferred from the Filicales to the Pteridosperms. In a few instances seeds
have been found in organic connexion with Medullosan foliage, and there
can be no reasonable doubt that Trigonocarpus, some forms of
Rhabdocarpus, Pachytesta, and other seeds represent the integumented
megasporangia of Medullosa or some closely allied genus.
Before attempting to summarise the salient features of Medullosa a
description of a few selected types will serve to place us in a better position
to consider the genus as a whole. The British species are placed first on the
ground that they are both geologically the oldest though, historically, the
most recently described, representatives of the genus; and in the
organisation of the stem they are simpler than the continental species. Their
resemblance to Heterangium serves to some extent to bridge the gap
between the majority of species of Medullosa and the simpler types of
Pteridosperms represented by Heterangium and Lyginopteris.
Medullosa anglica Scott[245].
Prior to the discovery of this species the genus Medullosa had not been
recorded from Britain. A section in the Williamson collection recognised by
Scott as that of a Medullosa had been identified by Williamson as a large
Heterangium stem. An undescribed specimen was found by Arber[246] in the
genus in North America during the Carboniferous period[242].
The name Medullosa was applied by Cotta[243] to three types, Medullosa
elegans, M. stellata, and M. porosa, from the Rothliegende of the Chemnitz
district. The first of these was recognised by Brongniart[244] as a distinct
genus for which he proposed the designation Myeloxylon and this was
afterwards identified by Renault, Williamson, and other palaeobotanists as a
petiole and not a stem. Further reference is made to Myeloxylon on a later
page. Cotta spoke of Medullosa as the most puzzling of the genera dealt
with in his ‘Dendrolithen,’ and in spite of the many additions to our
knowledge the position of this Palaeozoic genus is still a fertile source of
speculation. The generic designation Medullosa is applied to stems, with or
without petioles; petioles or rachises of fronds that frequently occur apart
from stems are referred to the genus Myeloxylon. The leaves of Medullosa
include several well-known species of Carboniferous and Permian genera
such as Alethopteris, Neuropteris and others that have in recent years been
transferred from the Filicales to the Pteridosperms. In a few instances seeds
have been found in organic connexion with Medullosan foliage, and there
can be no reasonable doubt that Trigonocarpus, some forms of
Rhabdocarpus, Pachytesta, and other seeds represent the integumented
megasporangia of Medullosa or some closely allied genus.
Before attempting to summarise the salient features of Medullosa a
description of a few selected types will serve to place us in a better position
to consider the genus as a whole. The British species are placed first on the
ground that they are both geologically the oldest though, historically, the
most recently described, representatives of the genus; and in the
organisation of the stem they are simpler than the continental species. Their
resemblance to Heterangium serves to some extent to bridge the gap
between the majority of species of Medullosa and the simpler types of
Pteridosperms represented by Heterangium and Lyginopteris.
Medullosa anglica Scott[245].
Prior to the discovery of this species the genus Medullosa had not been
recorded from Britain. A section in the Williamson collection recognised by
Scott as that of a Medullosa had been identified by Williamson as a large
Heterangium stem. An undescribed specimen was found by Arber[246] in the
Page 128
Binney collection at Cambridge which afforded some additional
information as to the structure of the roots.
The specimens on which Scott’s thorough description is based were
obtained by Messrs Wilde and Lomax from the Lower Coal Measures of
Lancashire. The stem of this oldest species has the habit of a tree-fern and is
almost completely invested by the stout decurrent bases of the petioles of
large spirally disposed compound fronds with a phyllotaxis of ⅖, the leaves
of the same orthostichy being separated from one another by a vertical
distance of approximately 10 cm.
A transverse section of a slightly flattened stem is shown in fig. 416, A,
the bases of three petioles give to it an angular form. Its dimensions are
approximately 10 × 4 cm. The ground-tissue of two of the petioles is
continuous with that of the stem, while that of the third leaf-stalk is cut
through near its separation from the stem and its adaxial face is already
defined by a hypodermal band of stereome, d. The surface of the stem is
characterised by fine longitudinal ribs caused by the slightly projecting
stereome in the outer cortex, and from the narrow furrows between the leaf-
bases adventitious roots emerge in vertical series. The position of an
interfoliar furrow is shown by a small arrow in fig. 416, A. There are three
steles, 2–3 cm. × 6–10 mm. in diameter: each agrees very closely in
structure with the single stele of Heterangium. Medullosa anglica may be
described as a polystelic Heterangium and as having the same relation to
Heterangium as regards the stelar system as Primula auricula bears to the
monostelic Primula. The central core of the stele (the black patches in the
diagram, fig. 416, A) consists of an anastomosing system of tracheal groups
embedded in an irregular parenchymatous reticulum. The large primary
tracheids reach a diameter of 150μ and have multiseriate pitting: at the
periphery of the primary xylem there is a more definite grouping of
tracheids as in Heterangium, and the slightly internal (mesarch) protoxylem
elements are associated with scalariform and densely spiral tracheids (fig.
416, B, C) narrower than the more internal reticulate elements. The
secondary xylem is manoxylic as in Cycads, tracheids in 2–4 radial series
alternating with medullary rays 1–3 cells broad and usually of considerable
depth (fig. 416, B). The principal rays are continuous with the
parenchymatous matrix of the central core. Thick-walled tubular elements,
information as to the structure of the roots.
The specimens on which Scott’s thorough description is based were
obtained by Messrs Wilde and Lomax from the Lower Coal Measures of
Lancashire. The stem of this oldest species has the habit of a tree-fern and is
almost completely invested by the stout decurrent bases of the petioles of
large spirally disposed compound fronds with a phyllotaxis of ⅖, the leaves
of the same orthostichy being separated from one another by a vertical
distance of approximately 10 cm.
A transverse section of a slightly flattened stem is shown in fig. 416, A,
the bases of three petioles give to it an angular form. Its dimensions are
approximately 10 × 4 cm. The ground-tissue of two of the petioles is
continuous with that of the stem, while that of the third leaf-stalk is cut
through near its separation from the stem and its adaxial face is already
defined by a hypodermal band of stereome, d. The surface of the stem is
characterised by fine longitudinal ribs caused by the slightly projecting
stereome in the outer cortex, and from the narrow furrows between the leaf-
bases adventitious roots emerge in vertical series. The position of an
interfoliar furrow is shown by a small arrow in fig. 416, A. There are three
steles, 2–3 cm. × 6–10 mm. in diameter: each agrees very closely in
structure with the single stele of Heterangium. Medullosa anglica may be
described as a polystelic Heterangium and as having the same relation to
Heterangium as regards the stelar system as Primula auricula bears to the
monostelic Primula. The central core of the stele (the black patches in the
diagram, fig. 416, A) consists of an anastomosing system of tracheal groups
embedded in an irregular parenchymatous reticulum. The large primary
tracheids reach a diameter of 150μ and have multiseriate pitting: at the
periphery of the primary xylem there is a more definite grouping of
tracheids as in Heterangium, and the slightly internal (mesarch) protoxylem
elements are associated with scalariform and densely spiral tracheids (fig.
416, B, C) narrower than the more internal reticulate elements. The
secondary xylem is manoxylic as in Cycads, tracheids in 2–4 radial series
alternating with medullary rays 1–3 cells broad and usually of considerable
depth (fig. 416, B). The principal rays are continuous with the
parenchymatous matrix of the central core. Thick-walled tubular elements,
Page 129
no doubt of the nature of sieve-tubes, form a conspicuous feature in the
phloem.
The three steles occasionally divide and fuse with one another. The tissue
between the steles is crushed and disorganised and in the living plant was
probably small in amount. In the imperfectly preserved inner cortical region
there is a sinuous band of secondary parenchyma (periderm; fig. 416, A, c)
developed from a deep-seated phellogen; in older stems this formed the
superficial tissue after the fall of the leaves. There is no definite boundary
between the cortex of the stem and the petiole-bases except when the
hypoderm cuts across the cortex preparatory to the separation of a leaf-
stalk. The stem-cortex and the ground-tissue of the petioles consist of
parenchyma with numerous secretory canals, not sacs only as in
Heterangium, and are abundantly supplied with scattered vascular bundles
of collateral and exarch structure.
phloem.
The three steles occasionally divide and fuse with one another. The tissue
between the steles is crushed and disorganised and in the living plant was
probably small in amount. In the imperfectly preserved inner cortical region
there is a sinuous band of secondary parenchyma (periderm; fig. 416, A, c)
developed from a deep-seated phellogen; in older stems this formed the
superficial tissue after the fall of the leaves. There is no definite boundary
between the cortex of the stem and the petiole-bases except when the
hypoderm cuts across the cortex preparatory to the separation of a leaf-
stalk. The stem-cortex and the ground-tissue of the petioles consist of
parenchyma with numerous secretory canals, not sacs only as in
Heterangium, and are abundantly supplied with scattered vascular bundles
of collateral and exarch structure.
Page 130
Fig. 416. Medullosa stems. A-C, Medullosa anglica; A, transverse
section; a, accessory vascular strand; b, accessory strand enclosed
by periderm; c, band of periderm encircling steles; d,
sclerenchyma between leaf and stem. B and C, longitudinal
section; a, accessory vascular strand; b, accessory strand enclosed
by periderm; c, band of periderm encircling steles; d,
sclerenchyma between leaf and stem. B and C, longitudinal
Page 131
sections. (After Scott.) D, Medullosa stellata; a, star-rings; p,
‘partial pith.’ (After Weber and Sterzel.) E, Medullosa Solmsi.
(After Weber and Sterzel.) F, Medullosa stellata, from a specimen
in the British Museum (No. 13767). G, Medullosa stellata var.
cortica; v, leaf-bundles. (After Weber and Sterzel.) H, I, Medullosa
Leuckarti. (After Weber and Sterzel and Solms-Laubach.) K,
Medullosa stellata var. gigantea; a, concentric stele; b, b, later
cylinders of centrifugal tissue. (Adapted from Weber and Sterzel.)
L, Medullosa Solmsi var. lignosa. M, Medullosa porosa. (L, M, after
Weber and Sterzel.)
The leaf-traces are furnished by the peripheral tracheal groups at the free
surface of the primary portion of each stele: each trace is at first concentric
and consists of primary xylem with one or more protoxylem strands near
the outer surface and is completely or partially enclosed by secondary
xylem and phloem. In the course of its passage to the leaf a leaf-trace loses
its secondary tissues, which were added by the cambium during the traverse
of the zone of secondary wood, and divides into small collateral bundles
consisting mainly of spiral and scalariform tracheids. The collateral bundles
accompanied by some narrow fibres are of the Myeloxylon type (fig. 420),
the xylem being wholly centripetal. In the behaviour of the leaf-traces and
in the vascular system of the petioles Medullosa differs from Heterangium
and Lyginopteris. Each leaf-base is supplied by sets of vascular strands
which pass into it from the stem at different levels; a large leaf-base
reaching 4 cm. in diameter receives as many as 70–80 bundles. The
hypoderm is like that first described in the French species Myeloxylon
Landriotii[247] and often spoken of as the Sparganum type of hypoderm. The
branching of the rachises points to a compound frond, and the occurrence of
numerous linear pinnules with revolute margins (fig. 420, D) in association
with the stem suggests that the ultimate segments were of the Alethopteris
form. This inference receives confirmation from the occurrence of petrified
specimens of undoubted Alethopteris rachises with the structure of
Myeloxylon. It is practically certain that the leaves borne on the stems of
Medullosa anglica are those long known as Alethopteris lonchitica (Vol. ii.
A, p. 553, fig. 364).
An interesting feature in the stems is the occurrence of cortical vascular
strands (fig. 416, A, a, b), reaching a diameter of 7 mm., containing
‘partial pith.’ (After Weber and Sterzel.) E, Medullosa Solmsi.
(After Weber and Sterzel.) F, Medullosa stellata, from a specimen
in the British Museum (No. 13767). G, Medullosa stellata var.
cortica; v, leaf-bundles. (After Weber and Sterzel.) H, I, Medullosa
Leuckarti. (After Weber and Sterzel and Solms-Laubach.) K,
Medullosa stellata var. gigantea; a, concentric stele; b, b, later
cylinders of centrifugal tissue. (Adapted from Weber and Sterzel.)
L, Medullosa Solmsi var. lignosa. M, Medullosa porosa. (L, M, after
Weber and Sterzel.)
The leaf-traces are furnished by the peripheral tracheal groups at the free
surface of the primary portion of each stele: each trace is at first concentric
and consists of primary xylem with one or more protoxylem strands near
the outer surface and is completely or partially enclosed by secondary
xylem and phloem. In the course of its passage to the leaf a leaf-trace loses
its secondary tissues, which were added by the cambium during the traverse
of the zone of secondary wood, and divides into small collateral bundles
consisting mainly of spiral and scalariform tracheids. The collateral bundles
accompanied by some narrow fibres are of the Myeloxylon type (fig. 420),
the xylem being wholly centripetal. In the behaviour of the leaf-traces and
in the vascular system of the petioles Medullosa differs from Heterangium
and Lyginopteris. Each leaf-base is supplied by sets of vascular strands
which pass into it from the stem at different levels; a large leaf-base
reaching 4 cm. in diameter receives as many as 70–80 bundles. The
hypoderm is like that first described in the French species Myeloxylon
Landriotii[247] and often spoken of as the Sparganum type of hypoderm. The
branching of the rachises points to a compound frond, and the occurrence of
numerous linear pinnules with revolute margins (fig. 420, D) in association
with the stem suggests that the ultimate segments were of the Alethopteris
form. This inference receives confirmation from the occurrence of petrified
specimens of undoubted Alethopteris rachises with the structure of
Myeloxylon. It is practically certain that the leaves borne on the stems of
Medullosa anglica are those long known as Alethopteris lonchitica (Vol. ii.
A, p. 553, fig. 364).
An interesting feature in the stems is the occurrence of cortical vascular
strands (fig. 416, A, a, b), reaching a diameter of 7 mm., containing
Page 132
scattered tracheids in a parenchymatous core surrounded by secondary
xylem and phloem. These cauline bundles are almost identical both in
structure and distribution with the accessory steles in the stem of a recent
Cycas, and the agreement is emphasised by the presence of short square-
ended tracheids in the primary xylem.
The roots branch freely and may attain a diameter of more than 1 cm.:
they are generally triarch and the triangular primary xylem is enclosed by
secondary xylem except opposite the protoxylem. The cortex is like that of
Lyginopteris roots and a conspicuous double layer of superficial tissue is
another feature common to both (cf. fig. 410). The exceptionally well
preserved specimens described by Arber[248] show very clearly the thick
zone of periderm which forms the covering of older roots, and in some of
the sieve-tubes groups of dark brown patches show the form and
arrangement of the sieve-plates.
Reproductive organs. We have as yet no precise information in regard to
the reproductive organs of Medullosa anglica, but there can be little or no
doubt that the fronds bore seeds that have long been known under the
generic name of Trigonocarpus. Many years ago Mr Hemingway noticed
the almost constant association of the fronds of Alethopteris lonchitica with
Trigonocarpus, and Dr Kidston’s discovery[249] of seed-bearing Neuropteris
pinnae considerably strengthened the evidence derived from mere
association. The structure of Trigonocarpus is described later (p. 117) in a
section devoted to reproductive organs attributed to Medullosa. Nothing is
known as to the microspore-bearing organs.
While in the structure of each of the steles Medullosa anglica agrees very
closely with Heterangium, it differs from that genus in the presence of three
steles and in the structure of the petioles which are much less fern-like than
the simpler petioles of Heterangium and Lyginopteris. From the continental
species the British species is distinguished by its simpler stelar system,
though there is a close correspondence as regards individual steles.
Medullosa pusilla Scott.
This species, briefly referred to by Scott in 1909[250] and fully described
in a recent paper[251], is founded on material from the Lower Coal Measures
of Colne, Lancashire. It agrees in essential features with Medullosa anglica,
xylem and phloem. These cauline bundles are almost identical both in
structure and distribution with the accessory steles in the stem of a recent
Cycas, and the agreement is emphasised by the presence of short square-
ended tracheids in the primary xylem.
The roots branch freely and may attain a diameter of more than 1 cm.:
they are generally triarch and the triangular primary xylem is enclosed by
secondary xylem except opposite the protoxylem. The cortex is like that of
Lyginopteris roots and a conspicuous double layer of superficial tissue is
another feature common to both (cf. fig. 410). The exceptionally well
preserved specimens described by Arber[248] show very clearly the thick
zone of periderm which forms the covering of older roots, and in some of
the sieve-tubes groups of dark brown patches show the form and
arrangement of the sieve-plates.
Reproductive organs. We have as yet no precise information in regard to
the reproductive organs of Medullosa anglica, but there can be little or no
doubt that the fronds bore seeds that have long been known under the
generic name of Trigonocarpus. Many years ago Mr Hemingway noticed
the almost constant association of the fronds of Alethopteris lonchitica with
Trigonocarpus, and Dr Kidston’s discovery[249] of seed-bearing Neuropteris
pinnae considerably strengthened the evidence derived from mere
association. The structure of Trigonocarpus is described later (p. 117) in a
section devoted to reproductive organs attributed to Medullosa. Nothing is
known as to the microspore-bearing organs.
While in the structure of each of the steles Medullosa anglica agrees very
closely with Heterangium, it differs from that genus in the presence of three
steles and in the structure of the petioles which are much less fern-like than
the simpler petioles of Heterangium and Lyginopteris. From the continental
species the British species is distinguished by its simpler stelar system,
though there is a close correspondence as regards individual steles.
Medullosa pusilla Scott.
This species, briefly referred to by Scott in 1909[250] and fully described
in a recent paper[251], is founded on material from the Lower Coal Measures
of Colne, Lancashire. It agrees in essential features with Medullosa anglica,
Page 133
but differs in the following particulars: the linear dimensions of the stem are
about one quarter those of a typical stem of the older species; the leaf-traces
possess little or no secondary xylem and the relatively large decurrent leaf-
bases have a narrower and simpler hypoderm. The stem has a tri-stelar
vascular system enclosed in a ring of internal periderm, and each stele (3
mm. in diameter) consists of a roughly triangular strand of reticulate
tracheids and a small amount of scattered parenchyma. The protoxylem is
either exarch or, as in M. anglica, mesarch, the exact position being difficult
to determine in the available material. The secondary xylem closely
resembles that of M. anglica.
Scott suggests the possibility that Alethopteris decurrens may be the
foliage of Medullosa pusilla. It is possible that there is no specific
difference between M. pusilla and M. anglica, but on the present evidence
the employment of a distinctive name is desirable.
Medullosa centrofilis de Fraine.
This species was founded by Miss de Fraine[252] on a petrified stem from
the Lower Coal Measures of Lancashire. The maximum diameter of the
flattened stem including four decurrent leaf-bases is 5 cm. The vascular
system consists of an outer group of four steles, reduced to three by fusion
in the upper part of the specimen, enclosing a central smaller stele or star-
ring (fig. 417). It is the presence of the star-ring that distinguishes this type
from the other two British species and forms a connecting link with certain
continental Medullosae. The peripheral steles agree with the steles of M.
anglica but, as in M. pusilla, there is some doubt as to the exarch or
mesarch position of the protoxylem. In the structure of the xylem the central
stele conforms to the rest of the vascular system and a strand of protoxylem
is preserved that is almost certainly exarch. There is evidence that the
peripheral steles occasionally anastomose, but the central stele follows an
independent course at least in the piece of stem examined. Leaf-traces are
furnished by the primary xylem of the outer steles, and they appear to be
without secondary tracheids as in M. pusilla. A zone of secondary cortex
encloses the vascular system as in the other British stems: it is pointed out
by Miss de Fraine[253] that this tissue, usually described as a deep-seated
periderm, must have differed from cork in that there is no sign of drying up
or decay in the tissues external to it. The leaf-bases are of the usual
about one quarter those of a typical stem of the older species; the leaf-traces
possess little or no secondary xylem and the relatively large decurrent leaf-
bases have a narrower and simpler hypoderm. The stem has a tri-stelar
vascular system enclosed in a ring of internal periderm, and each stele (3
mm. in diameter) consists of a roughly triangular strand of reticulate
tracheids and a small amount of scattered parenchyma. The protoxylem is
either exarch or, as in M. anglica, mesarch, the exact position being difficult
to determine in the available material. The secondary xylem closely
resembles that of M. anglica.
Scott suggests the possibility that Alethopteris decurrens may be the
foliage of Medullosa pusilla. It is possible that there is no specific
difference between M. pusilla and M. anglica, but on the present evidence
the employment of a distinctive name is desirable.
Medullosa centrofilis de Fraine.
This species was founded by Miss de Fraine[252] on a petrified stem from
the Lower Coal Measures of Lancashire. The maximum diameter of the
flattened stem including four decurrent leaf-bases is 5 cm. The vascular
system consists of an outer group of four steles, reduced to three by fusion
in the upper part of the specimen, enclosing a central smaller stele or star-
ring (fig. 417). It is the presence of the star-ring that distinguishes this type
from the other two British species and forms a connecting link with certain
continental Medullosae. The peripheral steles agree with the steles of M.
anglica but, as in M. pusilla, there is some doubt as to the exarch or
mesarch position of the protoxylem. In the structure of the xylem the central
stele conforms to the rest of the vascular system and a strand of protoxylem
is preserved that is almost certainly exarch. There is evidence that the
peripheral steles occasionally anastomose, but the central stele follows an
independent course at least in the piece of stem examined. Leaf-traces are
furnished by the primary xylem of the outer steles, and they appear to be
without secondary tracheids as in M. pusilla. A zone of secondary cortex
encloses the vascular system as in the other British stems: it is pointed out
by Miss de Fraine[253] that this tissue, usually described as a deep-seated
periderm, must have differed from cork in that there is no sign of drying up
or decay in the tissues external to it. The leaf-bases are of the usual
Page 134
Myeloxylon type. In size this species is intermediate between Medullosa
anglica and M. pusilla.
Fig. 417. Medullosa centrofilis. Transverse section showing the deep-
seated ‘periderm’ (broken line) surrounding four steles. (After de
Fraine.)
Medullosa stellata Cotta.
Cotta[254] described Medullosa stellata as a stem characterised by the
occurrence of several many-rayed stellate columns (‘vielstrahlige
Sternsäule’) in a pith enclosed by a double cylinder of secondary xylem.
The so-called pith is the central ground-tissue of the stem and the double
‘striated ring’ of Cotta is a cylindrical stele identical in structure with each
of the steles of Medullosa anglica but having a tubular form instead of
forming a relatively broad and short band (cf. fig. 416, D and A).
Goeppert[255] in his Permian Flora gave a detailed account of the species,
some of his sections being cut from Cotta’s material, and by the
employment of varietal epithets emphasised the range of variation within
the limits of the type. Goeppert and Stenzel[256] and, several years later,
Weber and Sterzel[257] adopted the same plan as a convenient method of
drawing attention to differences in anatomical characters. As Schenk[258]
pointed out, there is a considerable risk in the case of small pieces of stems
of attaching excessive importance to structural variations, and it is by no
means improbable, as he said, that differences which are the expression of
states of preservation or stages in development have been incorrectly
regarded as distinguishing marks of individual plants. It is, however,
convenient to recognise some of the more striking deviations from the type-
anglica and M. pusilla.
Fig. 417. Medullosa centrofilis. Transverse section showing the deep-
seated ‘periderm’ (broken line) surrounding four steles. (After de
Fraine.)
Medullosa stellata Cotta.
Cotta[254] described Medullosa stellata as a stem characterised by the
occurrence of several many-rayed stellate columns (‘vielstrahlige
Sternsäule’) in a pith enclosed by a double cylinder of secondary xylem.
The so-called pith is the central ground-tissue of the stem and the double
‘striated ring’ of Cotta is a cylindrical stele identical in structure with each
of the steles of Medullosa anglica but having a tubular form instead of
forming a relatively broad and short band (cf. fig. 416, D and A).
Goeppert[255] in his Permian Flora gave a detailed account of the species,
some of his sections being cut from Cotta’s material, and by the
employment of varietal epithets emphasised the range of variation within
the limits of the type. Goeppert and Stenzel[256] and, several years later,
Weber and Sterzel[257] adopted the same plan as a convenient method of
drawing attention to differences in anatomical characters. As Schenk[258]
pointed out, there is a considerable risk in the case of small pieces of stems
of attaching excessive importance to structural variations, and it is by no
means improbable, as he said, that differences which are the expression of
states of preservation or stages in development have been incorrectly
regarded as distinguishing marks of individual plants. It is, however,
convenient to recognise some of the more striking deviations from the type-
Page 135
species by speaking of the different forms as varieties though, as Weber and
Sterzel fully admit, such varieties and even some of the species must be
looked upon as provisional. Weber and Sterzel give expression to the
provisional nature of their grouping by classifying the species with their
varieties into form-cycles. Under the form-cycle Medullosa stellata five
more or less well defined forms are recognised, the type-species being
Medullosa stellata var. typica[259].
Medullosa stellata var. typica.
Part of a transverse section of a cylindrical stem is represented
diagrammatically in fig. 416, D. Very little of the cortex is preserved: a
parenchymatous axial region with scattered secretory canals contains four
oval or cylindrical vascular steles, the stellate columns of Cotta or star-rings
of later authors. These are of the same nature as the small central stele in the
English Medullosa centrofilis. The central region of the stem in this
specimen is completely surrounded by a narrow cylinder of inversely
orientated secondary xylem and phloem (fig. 416, D), the phloem being on
the inner side of the xylem. Beyond the xylem is a parenchymatous band
containing scattered groups of primary xylem tracheids with spiral,
scalariform, and reticulate pitting, and this zone, which is usually
designated the ‘partial pith,’ is succeeded by a second and broader, normally
orientated, cylinder of secondary xylem and phloem. In this section the two
concentric cylinders separated by the partial pith form a solenostele like that
of several recent Ferns except in the presence of secondary tissue. The term
‘partial pith’ applied to the tissue between the two cylinders of secondary
tissue is misleading: this tissue (fig. 416, D, p) is the primary xylem of the
stele and is homologous with the primary portion of the stele of
Heterangium and of the steles of M. anglica. In many sections the
continuity of the tubular stele is broken. In a section in the British Museum
cut from one of Cotta’s specimens[260], 6 × 3·5 cm. in diameter to the outer
edge of the vascular tissue, the cylindrical stele is interrupted at two places.
An example of the interrupted type of stele is shown in fig. 416, F, and in
fig. 416, H: the latter belongs to a distinct species. The complete type of
cylindrical stele is exceptional and occurs occasionally at different levels in
the stem. An important point is that the frequent breaks in the cylinder are
not connected with the exit of leaf-traces and do not, therefore, correspond
to the foliar gaps in the solenostele or dictyostele of a Fern.
Sterzel fully admit, such varieties and even some of the species must be
looked upon as provisional. Weber and Sterzel give expression to the
provisional nature of their grouping by classifying the species with their
varieties into form-cycles. Under the form-cycle Medullosa stellata five
more or less well defined forms are recognised, the type-species being
Medullosa stellata var. typica[259].
Medullosa stellata var. typica.
Part of a transverse section of a cylindrical stem is represented
diagrammatically in fig. 416, D. Very little of the cortex is preserved: a
parenchymatous axial region with scattered secretory canals contains four
oval or cylindrical vascular steles, the stellate columns of Cotta or star-rings
of later authors. These are of the same nature as the small central stele in the
English Medullosa centrofilis. The central region of the stem in this
specimen is completely surrounded by a narrow cylinder of inversely
orientated secondary xylem and phloem (fig. 416, D), the phloem being on
the inner side of the xylem. Beyond the xylem is a parenchymatous band
containing scattered groups of primary xylem tracheids with spiral,
scalariform, and reticulate pitting, and this zone, which is usually
designated the ‘partial pith,’ is succeeded by a second and broader, normally
orientated, cylinder of secondary xylem and phloem. In this section the two
concentric cylinders separated by the partial pith form a solenostele like that
of several recent Ferns except in the presence of secondary tissue. The term
‘partial pith’ applied to the tissue between the two cylinders of secondary
tissue is misleading: this tissue (fig. 416, D, p) is the primary xylem of the
stele and is homologous with the primary portion of the stele of
Heterangium and of the steles of M. anglica. In many sections the
continuity of the tubular stele is broken. In a section in the British Museum
cut from one of Cotta’s specimens[260], 6 × 3·5 cm. in diameter to the outer
edge of the vascular tissue, the cylindrical stele is interrupted at two places.
An example of the interrupted type of stele is shown in fig. 416, F, and in
fig. 416, H: the latter belongs to a distinct species. The complete type of
cylindrical stele is exceptional and occurs occasionally at different levels in
the stem. An important point is that the frequent breaks in the cylinder are
not connected with the exit of leaf-traces and do not, therefore, correspond
to the foliar gaps in the solenostele or dictyostele of a Fern.
Page 136
The secondary xylem is of the cycadean type (fig. 418, B, D) like that of
Heterangium and Lyginopteris and several other stems. Each of the star-
rings in the axial region consists of a parenchymatous core with scattered
primary tracheids enclosed by secondary vascular tissue (fig. 418, B). The
star-ring shown in fig. 418, B, from a Chemnitz stem illustrates the
characteristic cycadean character of the secondary xylem with broad
medullary rays: some of the innermost elements are in contact with the
primary tracheids. The phloem is rendered conspicuous by the black
contents in some of the elements. Both the star-rings and the larger
peripheral steles are constructed on the same plan and agree with the steles
of M. anglica. The star-rings occasionally branch and anastomose with one
another and with the encircling stele. The star-ring in fig. 416, D at a is
about to give off a small strand.
Leaf-traces are furnished by the primary xylem at the edge of the ‘partial
pith’ of the outer stele: as a leaf-trace passes outwards through the outer
cylinder of secondary xylem the cambium invests it with secondary xylem
and phloem, but as it passes through the cortex of the stem it becomes
reduced to its primary elements, and by successive branching gives rise to
small collateral bundles which enter the petioles. The piece of stem shown
in fig. 416, G, illustrates the exit of leaf-traces from the stele and their
subsequent division into several small bundles, v, which are scattered in the
cortex with strands of sclerenchyma. In a specimen identified with
Medullosa stellata, Schenk[261] found part of a leaf-base attached to the
stem: its vascular system was of the Myeloxylon type, the bundles being
identical with those in the cortex of the stem seen in fig. 416, G.
In some stems of M. stellata the outer, centrifugally developed, portion of
the main stele is very much broader than in the example represented in fig.
416, D. The diagrammatic sketch reproduced in fig. 416, F, represents a
section of a Chemnitz specimen in the British Museum[262] in which the
axial region containing several star-rings is almost enclosed by an inner
zone of secondary xylem, and beyond the narrow primary xylem (black in
the sketch) the rest of the block consists exclusively of secondary xylem 5·5
cm. broad. This example illustrates a common tendency in Medullosa
towards a large excess of centrifugal over centripetal secondary vascular
tissue. A similar specimen of Medullosa stellata is figured by Mougeot[263]
from the Vosges showing a considerable development of centrifugal xylem
Heterangium and Lyginopteris and several other stems. Each of the star-
rings in the axial region consists of a parenchymatous core with scattered
primary tracheids enclosed by secondary vascular tissue (fig. 418, B). The
star-ring shown in fig. 418, B, from a Chemnitz stem illustrates the
characteristic cycadean character of the secondary xylem with broad
medullary rays: some of the innermost elements are in contact with the
primary tracheids. The phloem is rendered conspicuous by the black
contents in some of the elements. Both the star-rings and the larger
peripheral steles are constructed on the same plan and agree with the steles
of M. anglica. The star-rings occasionally branch and anastomose with one
another and with the encircling stele. The star-ring in fig. 416, D at a is
about to give off a small strand.
Leaf-traces are furnished by the primary xylem at the edge of the ‘partial
pith’ of the outer stele: as a leaf-trace passes outwards through the outer
cylinder of secondary xylem the cambium invests it with secondary xylem
and phloem, but as it passes through the cortex of the stem it becomes
reduced to its primary elements, and by successive branching gives rise to
small collateral bundles which enter the petioles. The piece of stem shown
in fig. 416, G, illustrates the exit of leaf-traces from the stele and their
subsequent division into several small bundles, v, which are scattered in the
cortex with strands of sclerenchyma. In a specimen identified with
Medullosa stellata, Schenk[261] found part of a leaf-base attached to the
stem: its vascular system was of the Myeloxylon type, the bundles being
identical with those in the cortex of the stem seen in fig. 416, G.
In some stems of M. stellata the outer, centrifugally developed, portion of
the main stele is very much broader than in the example represented in fig.
416, D. The diagrammatic sketch reproduced in fig. 416, F, represents a
section of a Chemnitz specimen in the British Museum[262] in which the
axial region containing several star-rings is almost enclosed by an inner
zone of secondary xylem, and beyond the narrow primary xylem (black in
the sketch) the rest of the block consists exclusively of secondary xylem 5·5
cm. broad. This example illustrates a common tendency in Medullosa
towards a large excess of centrifugal over centripetal secondary vascular
tissue. A similar specimen of Medullosa stellata is figured by Mougeot[263]
from the Vosges showing a considerable development of centrifugal xylem
Page 137
comparable with that in the British Museum stem. Weber and Sterzel[264]
describe stems of Medullosa stellata showing slight periodic swellings
which it is suggested, though there is no evidence in support of the opinion,
may be connected with reproductive organs.
Medullosa stellata var. corticata[265]. The specimen referred to this
variety, represented in fig. 416, G, has already been quoted as affording data
with regard to the origin and behaviour of the leaf-traces. In this type of
stem the outer portion of the main stele is narrower than in M. stellata var.
typica and the stele never forms a complete tube. The star-rings in the
centre of the stem are more numerous than in the type-species of the genus.
In the axial region of some stems included in the form-cycle to which M.
stellata belongs there may be flatter and tangentially elongated vascular
strands in addition to the cylindrical star-rings; these are termed plate-rings.
In Medullosa stellata var. lignosa[266] the outer xylem reaches a breadth of
4 cm. and the star-rings are reduced to one. The form M. stellata var.
gigantea[267] (fig. 416, K) is of special interest as an example of a stem
reaching a diameter of nearly 50 cm. and having as many as 43 large and
small star-rings in the axial region. A large tubular stele like that of the
type-species (fig. 416, D) surrounds the central region, but in this form the
cylindrical stele a is succeeded by concentric cylinders of normally
orientated xylem and phloem (fig. 416, K, bb) produced by successive
cambiums either cortical or pericyclic in origin. This type of stem presents a
striking resemblance to stems of Cycas and Macrozamia except in the
possession of a double cylindrical stele consisting of both centripetal and
centrifugal secondary xylem and phloem separated by a zone of primary
xylem (partial pith).
Medullosa gigas Renault.
This species was founded on a piece of stem from the Permian of
Autun[268], consisting almost entirely of secondary xylem, which Brongniart
had previously placed in his genus Palaeoxylon[269]. The secondary xylem
reaches a diameter of 45–50 cm. and in the portion of the central region
preserved there are a few vascular strands like the star-rings of other
describe stems of Medullosa stellata showing slight periodic swellings
which it is suggested, though there is no evidence in support of the opinion,
may be connected with reproductive organs.
Medullosa stellata var. corticata[265]. The specimen referred to this
variety, represented in fig. 416, G, has already been quoted as affording data
with regard to the origin and behaviour of the leaf-traces. In this type of
stem the outer portion of the main stele is narrower than in M. stellata var.
typica and the stele never forms a complete tube. The star-rings in the
centre of the stem are more numerous than in the type-species of the genus.
In the axial region of some stems included in the form-cycle to which M.
stellata belongs there may be flatter and tangentially elongated vascular
strands in addition to the cylindrical star-rings; these are termed plate-rings.
In Medullosa stellata var. lignosa[266] the outer xylem reaches a breadth of
4 cm. and the star-rings are reduced to one. The form M. stellata var.
gigantea[267] (fig. 416, K) is of special interest as an example of a stem
reaching a diameter of nearly 50 cm. and having as many as 43 large and
small star-rings in the axial region. A large tubular stele like that of the
type-species (fig. 416, D) surrounds the central region, but in this form the
cylindrical stele a is succeeded by concentric cylinders of normally
orientated xylem and phloem (fig. 416, K, bb) produced by successive
cambiums either cortical or pericyclic in origin. This type of stem presents a
striking resemblance to stems of Cycas and Macrozamia except in the
possession of a double cylindrical stele consisting of both centripetal and
centrifugal secondary xylem and phloem separated by a zone of primary
xylem (partial pith).
Medullosa gigas Renault.
This species was founded on a piece of stem from the Permian of
Autun[268], consisting almost entirely of secondary xylem, which Brongniart
had previously placed in his genus Palaeoxylon[269]. The secondary xylem
reaches a diameter of 45–50 cm. and in the portion of the central region
preserved there are a few vascular strands like the star-rings of other
Page 138
species. The considerable development of secondary xylem indicates a form
of stem similar to some forms of M. stellata (e.g. fig. 416, F), but as the
available data are insufficient for accurate determination Renault’s specific
name is retained. Renault describes the internal xylem cylinder (i.e. the
centripetal xylem) as very slightly developed or as hardly visible, a feature
in which the French specimen shows a nearer approach to the structure of a
recent Cycad.
Medullosa porosa Cotta.
The second of Cotta’s species[270], which has been fully investigated by
Weber and Sterzel, is constructed on the same plan as that of M. stellata,
but the stem is distinguished by the greater number of star-rings and, more
especially, by the presence of an outer system of vascular strands in the
axial region (fig. 416, M): these form a frequently interrupted cylinder of
anastomosing strands characterised by the feeble development of secondary
xylem and phloem or by the absence of this tissue on the outer face of the
strands. The component parts of this outer series occasionally fuse with the
internal star-rings.
Medullosa Solmsi Schenk[271] var. typica Web. and Ster.[272]
This type has a large axial region containing several very small star-rings
enclosed by two concentric zones of separate plate-rings (fig. 416, E) each
consisting of a complete flattened cylinder of secondary xylem and phloem
enclosing primary xylem. As the complete cylindrical stele of the stem of
Medullosa stellata shown in fig. 416, D, was compared with the solenostele
of a Fern, so in this stem (fig. 416, E) the vascular cylinder may be
compared at least superficially with a dictyostele. From the inner circle of
plate-rings strands are given off in the form of star-rings and these pass
through the gaps in the outer system, eventually breaking up in the cortex
into numerous collateral bundles. In another form of this species, var.
lignosa (fig. 416, L), the axial region is enclosed by a circle of plate-rings
like those in the type-form, but these are succeeded by a circle of very
asymmetrically developed and large steles with the outer xylem and phloem
much broader than the inner. Moreover in this form additional cylinders of
normally orientated vascular tissue are added as in M. stellata var. gigantea
and in some recent Cycads. It is noteworthy that the secondary wood of
of stem similar to some forms of M. stellata (e.g. fig. 416, F), but as the
available data are insufficient for accurate determination Renault’s specific
name is retained. Renault describes the internal xylem cylinder (i.e. the
centripetal xylem) as very slightly developed or as hardly visible, a feature
in which the French specimen shows a nearer approach to the structure of a
recent Cycad.
Medullosa porosa Cotta.
The second of Cotta’s species[270], which has been fully investigated by
Weber and Sterzel, is constructed on the same plan as that of M. stellata,
but the stem is distinguished by the greater number of star-rings and, more
especially, by the presence of an outer system of vascular strands in the
axial region (fig. 416, M): these form a frequently interrupted cylinder of
anastomosing strands characterised by the feeble development of secondary
xylem and phloem or by the absence of this tissue on the outer face of the
strands. The component parts of this outer series occasionally fuse with the
internal star-rings.
Medullosa Solmsi Schenk[271] var. typica Web. and Ster.[272]
This type has a large axial region containing several very small star-rings
enclosed by two concentric zones of separate plate-rings (fig. 416, E) each
consisting of a complete flattened cylinder of secondary xylem and phloem
enclosing primary xylem. As the complete cylindrical stele of the stem of
Medullosa stellata shown in fig. 416, D, was compared with the solenostele
of a Fern, so in this stem (fig. 416, E) the vascular cylinder may be
compared at least superficially with a dictyostele. From the inner circle of
plate-rings strands are given off in the form of star-rings and these pass
through the gaps in the outer system, eventually breaking up in the cortex
into numerous collateral bundles. In another form of this species, var.
lignosa (fig. 416, L), the axial region is enclosed by a circle of plate-rings
like those in the type-form, but these are succeeded by a circle of very
asymmetrically developed and large steles with the outer xylem and phloem
much broader than the inner. Moreover in this form additional cylinders of
normally orientated vascular tissue are added as in M. stellata var. gigantea
and in some recent Cycads. It is noteworthy that the secondary wood of
Page 139
Medullosa Solmsi is rather more compact than in other species, a feature in
which it to some extent agrees with the South African genus Rhexoxylon.
Medullosa Leuckarti Goeppert and Stenzel.
In this species[273], also from the Permian of Saxony, the central region
including some star-rings is surrounded by sinuous flattened concentric
steles (snake-rings) agreeing anatomically with the steles of other species
and characterised by the comparatively small breadth of the secondary
xylem and phloem (fig. 416, H). Leaf-traces are given off, as in M. anglica
and other species, from the outer edge of the primary xylem. In some forms
there is a single set of snake-rings; in others there is a double series. Fig.
418, D, shows part of the secondary xylem of a stele of this species from
Chemnitz: the tracheids are in some places continuous with the primary
xylem, and on the outer edge of the secondary wood is a cylinder of
phloem. A section of Medullosa Leuckarti figured by Goeppert and
Stenzel[274] shows some radial rows of very thick-walled elements in the
secondary phloem which they describe as bast sclerenchyma, but Solms-
Laubach[275] believes them to be sieve-tubes. Precisely similar elements are
figured by Scott[276] in M. anglica and as this author suggests the thick walls
are probably not an original feature. The structure of the primary xylem is
more clearly seen in fig. 418, C, and the relation between primary and
secondary xylem is shown in fig. 416, I, where the position of the
protoxylem may be either exarch or mesarch. The protoxylem is only
occasionally recognisable but some of the peripheral primary tracheal
groups are undoubtedly mesarch. External to the stele, a part of which is
reproduced in fig. 418, D, are strands of stereome elements and beyond
them a band of radially elongated cells that may be ‘periderm’: still farther
out there are some imperfectly preserved vascular bundles that are leaf-
traces. This species is important as affording a complete demonstration of
the organic connexion between the stem and petioles of the Myeloxylon
Landrioti type which indicate that the fronds were probably Alethopteroid.
which it to some extent agrees with the South African genus Rhexoxylon.
Medullosa Leuckarti Goeppert and Stenzel.
In this species[273], also from the Permian of Saxony, the central region
including some star-rings is surrounded by sinuous flattened concentric
steles (snake-rings) agreeing anatomically with the steles of other species
and characterised by the comparatively small breadth of the secondary
xylem and phloem (fig. 416, H). Leaf-traces are given off, as in M. anglica
and other species, from the outer edge of the primary xylem. In some forms
there is a single set of snake-rings; in others there is a double series. Fig.
418, D, shows part of the secondary xylem of a stele of this species from
Chemnitz: the tracheids are in some places continuous with the primary
xylem, and on the outer edge of the secondary wood is a cylinder of
phloem. A section of Medullosa Leuckarti figured by Goeppert and
Stenzel[274] shows some radial rows of very thick-walled elements in the
secondary phloem which they describe as bast sclerenchyma, but Solms-
Laubach[275] believes them to be sieve-tubes. Precisely similar elements are
figured by Scott[276] in M. anglica and as this author suggests the thick walls
are probably not an original feature. The structure of the primary xylem is
more clearly seen in fig. 418, C, and the relation between primary and
secondary xylem is shown in fig. 416, I, where the position of the
protoxylem may be either exarch or mesarch. The protoxylem is only
occasionally recognisable but some of the peripheral primary tracheal
groups are undoubtedly mesarch. External to the stele, a part of which is
reproduced in fig. 418, D, are strands of stereome elements and beyond
them a band of radially elongated cells that may be ‘periderm’: still farther
out there are some imperfectly preserved vascular bundles that are leaf-
traces. This species is important as affording a complete demonstration of
the organic connexion between the stem and petioles of the Myeloxylon
Landrioti type which indicate that the fronds were probably Alethopteroid.
Page 140
Fig. 418. A, Myeloxylon radiatum, part of petiole. B, Medullosa stellata;
star-ring; × 14. C, D, Medullosa Leuckarti; C, primary xylem; D,
part of primary stelar tissues and secondary xylem and phloem; ×
6. (A–D, Kidston Coll., 1014, 1307, 1238.)
star-ring; × 14. C, D, Medullosa Leuckarti; C, primary xylem; D,
part of primary stelar tissues and secondary xylem and phloem; ×
6. (A–D, Kidston Coll., 1014, 1307, 1238.)
Page 141
The specimen on which the diagrammatic drawing reproduced in fig. 419
is based has been investigated by Weber and Sterzel[277] and by Solms-
Laubach[278]. The figure is a slightly simplified version of that given by
Weber and Sterzel; it represents the stem of Medullosa Leuckarti as a
transparent object, the two lower transverse sections, B and C, being seen in
perspective through the longitudinal faces. The steles are shaded obliquely
in the longitudinal sections, and in the three transverse sections, A, B, C, the
primary xylem (partial pith) is black and the enclosing secondary vascular
tissue radially shaded. The whole block is 9 cm. in length and 6 cm. broad.
Only a part of the axial region is shown internal to the peripheral snake-
rings and in it are the star-rings S, S, b, and c. Outside the main steles is the
narrow cortex R and portions of leaf-bases I–IV. The lowest section, C,
shows part of a peripheral snake-ring with a slight swelling at f on its inner
side which, as seen in sections B and A, foreshadows the separation of the
star-ring S and the consequent break in the continuity of the snake-ring (d,
e, sect. B). In section A the gap is closed: in the longitudinal section
between B and A the star-ring S is seen to form two branches, a and b, the
branch a closing the gap between d and e in section B. These sections
demonstrate the formation of a star-ring from the main peripheral stele and
the formation of additional star-rings by branching.
is based has been investigated by Weber and Sterzel[277] and by Solms-
Laubach[278]. The figure is a slightly simplified version of that given by
Weber and Sterzel; it represents the stem of Medullosa Leuckarti as a
transparent object, the two lower transverse sections, B and C, being seen in
perspective through the longitudinal faces. The steles are shaded obliquely
in the longitudinal sections, and in the three transverse sections, A, B, C, the
primary xylem (partial pith) is black and the enclosing secondary vascular
tissue radially shaded. The whole block is 9 cm. in length and 6 cm. broad.
Only a part of the axial region is shown internal to the peripheral snake-
rings and in it are the star-rings S, S, b, and c. Outside the main steles is the
narrow cortex R and portions of leaf-bases I–IV. The lowest section, C,
shows part of a peripheral snake-ring with a slight swelling at f on its inner
side which, as seen in sections B and A, foreshadows the separation of the
star-ring S and the consequent break in the continuity of the snake-ring (d,
e, sect. B). In section A the gap is closed: in the longitudinal section
between B and A the star-ring S is seen to form two branches, a and b, the
branch a closing the gap between d and e in section B. These sections
demonstrate the formation of a star-ring from the main peripheral stele and
the formation of additional star-rings by branching.
Page 142
Fig. 419. Medullosa Leuckarti. Diagrammatic sketch of stem showing
longitudinal and transverse sections: for explanation see text.
(After Weber and Sterzel.)
Numerous vascular bundles destined for the leaves are scattered in the
cortex. The course of the decurrent leaf-base I is shown on the longitudinal
faces, its boundary being marked by crowded stereome strands (of the
Myeloxylon Landrioti type); other leaf-bases are represented by II, III, and
IV.
In habit Medullosa Leuckarti differs from such a type as M. stellata in its
relatively shorter and stouter stem and in the shorter internodes.
longitudinal and transverse sections: for explanation see text.
(After Weber and Sterzel.)
Numerous vascular bundles destined for the leaves are scattered in the
cortex. The course of the decurrent leaf-base I is shown on the longitudinal
faces, its boundary being marked by crowded stereome strands (of the
Myeloxylon Landrioti type); other leaf-bases are represented by II, III, and
IV.
In habit Medullosa Leuckarti differs from such a type as M. stellata in its
relatively shorter and stouter stem and in the shorter internodes.
Page 143
Leaves and Reproductive Organs.
i. Leaves. It has already been stated that in some cases petioles occur in
organic connexion with Medullosan stems, notably in M. anglica and M.
Leuckarti: in the exceptionally rich collection in the Chemnitz Museum,
which forms a fitting memorial of the work of the late Prof. Sterzel, there is
a stem of M. Leuckarti bearing large petioles of the type known as
Myeloxylon radiatum. The occurrence of vascular bundles in the cortex of
other species of stem identical with those in the attached petioles points to a
uniform type of leaf-structure so far as regards the petioles and rachises of
Medullosa. While it is clearly unnecessary to distinguish by a special
generic title the petrified portions of fronds known to belong to certain
species of stems, the frequent occurrence of detached petioles necessitates
some distinctive term. The name employed is Myeloxylon: the genus was
instituted by Brongniart in 1849 for Cotta’s species Medullosa elegans the
petiolar nature of which was suspected by Binney in 1872.
Myeloxylon (Medullosan leaf-
stalks).
1832. Medullosa elegans Cotta.
1865. Stenzelia Goeppert.
1876. Myelopteris Renault[279];
1877. Aulacopteris Grand’Eury[280].
There is a very close agreement in general anatomical structure between
the numerous specimens of Myeloxylon from the Permian strata of Saxony
and France and the Coal Measures and Millstone Grit of England[281]; the
genus is also recorded from the Upper Carboniferous of Kansas[282]. Two
well-defined types instituted by Renault are, however, readily distinguished
by the form of the hypodermal stereome strands. Myeloxylon may be
defined as follows: Oval or cylindrical branched axes, reaching a diameter
of 15 cm., bearing pinnae having the characters of Alethopteris,
Neuropteris, Odontopteris, and some other genera that were formerly
classed as Ferns. Below a single-layered epidermis, in which stomata have
been recognised, occur a few layers of parenchyma: this superficial tissue,
which is rarely preserved, is succeeded by a hypodermal region consisting
of parenchymatous tissue and numerous vertical groups of narrow thick-
walled fibres arranged as radial plates or circular, oval, or reniform strands
i. Leaves. It has already been stated that in some cases petioles occur in
organic connexion with Medullosan stems, notably in M. anglica and M.
Leuckarti: in the exceptionally rich collection in the Chemnitz Museum,
which forms a fitting memorial of the work of the late Prof. Sterzel, there is
a stem of M. Leuckarti bearing large petioles of the type known as
Myeloxylon radiatum. The occurrence of vascular bundles in the cortex of
other species of stem identical with those in the attached petioles points to a
uniform type of leaf-structure so far as regards the petioles and rachises of
Medullosa. While it is clearly unnecessary to distinguish by a special
generic title the petrified portions of fronds known to belong to certain
species of stems, the frequent occurrence of detached petioles necessitates
some distinctive term. The name employed is Myeloxylon: the genus was
instituted by Brongniart in 1849 for Cotta’s species Medullosa elegans the
petiolar nature of which was suspected by Binney in 1872.
Myeloxylon (Medullosan leaf-
stalks).
1832. Medullosa elegans Cotta.
1865. Stenzelia Goeppert.
1876. Myelopteris Renault[279];
1877. Aulacopteris Grand’Eury[280].
There is a very close agreement in general anatomical structure between
the numerous specimens of Myeloxylon from the Permian strata of Saxony
and France and the Coal Measures and Millstone Grit of England[281]; the
genus is also recorded from the Upper Carboniferous of Kansas[282]. Two
well-defined types instituted by Renault are, however, readily distinguished
by the form of the hypodermal stereome strands. Myeloxylon may be
defined as follows: Oval or cylindrical branched axes, reaching a diameter
of 15 cm., bearing pinnae having the characters of Alethopteris,
Neuropteris, Odontopteris, and some other genera that were formerly
classed as Ferns. Below a single-layered epidermis, in which stomata have
been recognised, occur a few layers of parenchyma: this superficial tissue,
which is rarely preserved, is succeeded by a hypodermal region consisting
of parenchymatous tissue and numerous vertical groups of narrow thick-
walled fibres arranged as radial plates or circular, oval, or reniform strands
Page 144
(the Sparganum type of cortex). In the hypoderm as in the ground-tissue
generally secretory canals, often accompanied by stereome, are a
characteristic feature. The vascular system is represented by a considerable
number of collateral bundles scattered through the ground-tissue and
especially abundant in the outer region: the bundles sometimes assume a
more or less regular disposition in concentric circles. Each bundle consists
of a small group of xylem tracheids, for the most part spiral or scalariform,
though reticulately pitted elements are by no means rare, with a single
protoxylem group on the outer face next the phloem (fig. 420, B, C). As a
rule the xylem is wholly centripetal, but occasionally the exarch structure
becomes mesarch by the occurrence of a few centrifugal tracheids. The
phloem, rarely preserved (fig. 420, B), consists of narrow sieve-tubes with
parenchyma, and the bundle as a whole is often partially enclosed by a
sheath of fibres.
Superficially the anatomical structure is similar to that of the petioles of
Angiopteris or Marattia, and both Williamson[283] and Renault placed
Myeloxylon in the Ferns; but the collateral form of the vascular bundles, the
position of the protoxylem, and the arrangement of the hypoderm tissues,
are cycadean features.
Myeloxylon radiatum (Renault).
This type is characterised by the radially elongated stereome of the
hypoderm. Prof. Zeiller[284], who has given a very clear and concise
description of Myeloxylon, is disposed to regard Cotta’s Medullosa elegans
as a specifically distinct form on the ground that there are two concentric
zones of stereome in the hypoderm; but this feature is shown only in one of
Cotta’s figures, and Weber and Sterzel[285] point out that a doubting of the
hypoderm zone may be caused by accidental juxtaposition of two faulted
pieces of peripheral tissue. The drawing reproduced in fig. 420, A, shows
the structural plan of an unusually large petiole from the Permian of Autun:
a portion of the outer tissue is seen in fig. 418, A. The vascular bundle, fig.
420, C, from a Millstone Grit specimen[286], shows the centripetal nature of
the xylem and fragments of phloem in the outer half of the bundle, with
imperfectly preserved fibres abutting on the xylem. The characteristic
hypoderm is shown also in fig. 418, A; the double xylem strand on the left
illustrates a common feature caused by the branching of vascular bundles.
generally secretory canals, often accompanied by stereome, are a
characteristic feature. The vascular system is represented by a considerable
number of collateral bundles scattered through the ground-tissue and
especially abundant in the outer region: the bundles sometimes assume a
more or less regular disposition in concentric circles. Each bundle consists
of a small group of xylem tracheids, for the most part spiral or scalariform,
though reticulately pitted elements are by no means rare, with a single
protoxylem group on the outer face next the phloem (fig. 420, B, C). As a
rule the xylem is wholly centripetal, but occasionally the exarch structure
becomes mesarch by the occurrence of a few centrifugal tracheids. The
phloem, rarely preserved (fig. 420, B), consists of narrow sieve-tubes with
parenchyma, and the bundle as a whole is often partially enclosed by a
sheath of fibres.
Superficially the anatomical structure is similar to that of the petioles of
Angiopteris or Marattia, and both Williamson[283] and Renault placed
Myeloxylon in the Ferns; but the collateral form of the vascular bundles, the
position of the protoxylem, and the arrangement of the hypoderm tissues,
are cycadean features.
Myeloxylon radiatum (Renault).
This type is characterised by the radially elongated stereome of the
hypoderm. Prof. Zeiller[284], who has given a very clear and concise
description of Myeloxylon, is disposed to regard Cotta’s Medullosa elegans
as a specifically distinct form on the ground that there are two concentric
zones of stereome in the hypoderm; but this feature is shown only in one of
Cotta’s figures, and Weber and Sterzel[285] point out that a doubting of the
hypoderm zone may be caused by accidental juxtaposition of two faulted
pieces of peripheral tissue. The drawing reproduced in fig. 420, A, shows
the structural plan of an unusually large petiole from the Permian of Autun:
a portion of the outer tissue is seen in fig. 418, A. The vascular bundle, fig.
420, C, from a Millstone Grit specimen[286], shows the centripetal nature of
the xylem and fragments of phloem in the outer half of the bundle, with
imperfectly preserved fibres abutting on the xylem. The characteristic
hypoderm is shown also in fig. 418, A; the double xylem strand on the left
illustrates a common feature caused by the branching of vascular bundles.
Page 145
Several secretory canals are scattered in the ground-tissue. The pinnules of
Myeloxylon radiatum, or at least of some specimens, have been shown by
Renault to be of the Neuropteris type.
Fig. 420. A, B, Myeloxylon radiatum; A, petiole ⅔ nat. size; B, vascular
bundle. C, Myeloxylon sp. vascular bundle; px, protoxylem. D,
Medullosa anglica; section of pinnule. (A, B, after Zeiller; D, after
Scott.)
Myeloxylon Landrioti (Renault)[287].
In this species the distinguishing feature is the occurrence of the
hypodermal stereome in the form of circular, oval, or reniform strands in
place of the radial plates of M. radiatum. It is this form of petiole that was
borne by the stems of Medullosa anglica and M. Leuckarti. In M. anglica
the pinnules (fig. 420, D) are of the Alethopteris type, almost certainly A.
Myeloxylon radiatum, or at least of some specimens, have been shown by
Renault to be of the Neuropteris type.
Fig. 420. A, B, Myeloxylon radiatum; A, petiole ⅔ nat. size; B, vascular
bundle. C, Myeloxylon sp. vascular bundle; px, protoxylem. D,
Medullosa anglica; section of pinnule. (A, B, after Zeiller; D, after
Scott.)
Myeloxylon Landrioti (Renault)[287].
In this species the distinguishing feature is the occurrence of the
hypodermal stereome in the form of circular, oval, or reniform strands in
place of the radial plates of M. radiatum. It is this form of petiole that was
borne by the stems of Medullosa anglica and M. Leuckarti. In M. anglica
the pinnules (fig. 420, D) are of the Alethopteris type, almost certainly A.
Page 146
lonchitica. Renault and Zeiller have described French specimens of
Myeloxylon Landrioti bearing pinnules like those of Alethopteris aquilina
and A. Grandini.
Myeloxylon topekense (Penhallow).
The occurrence of Myeloxylon petioles in the New World was recorded
by the late Prof. Penhallow[288] who founded this species on some
imperfectly petrified specimens from Upper Carboniferous strata at Topeka,
Kansas. Enough material was available to show the Myeloxylon characters,
but the preservation is too imperfect to admit of a complete diagnosis. The
hypodermal stereome shows a tendency to form tangentially extended
strands in place of the more circular or radially elongated groups in the
European species.
In addition to Alethopteris, Neuropteris (including Cyclopteris) and
Odontopteris fronds, which are known to possess rachises with the
Myeloxylon features, there is reason to believe that the Permian Callipteris
fronds and possibly some of the older Taeniopteris leaves may also belong
to Medullosa[289]. It is, however, unsafe to assume that the occurrence of
Myeloxylon petioles necessarily denotes the existence of Medullosa. The
French stem Colpoxylon aeduense Brongn.[290] bore leaves with the same
general anatomical features as those of a typical Myeloxylon, and there can
be little doubt that other genera of the Medulloseae also possessed fronds
constructed on the same plan as those known to have been borne by
Medullosa. An interesting illustration of an injured organ that had produced
a wound-cambium is afforded by a Myeloxylon petiole from the Coal
Measures described by Mr Holden[291].
Reproductive Organs.
Reference was made in volume ii. to the reasons which led to the removal
of several genera of Carboniferous and Permian fronds from the Filicales to
the Pteridosperms, and in Chapter xxix. of the present volume certain
species of Sphenopteris are described as the foliage of Lyginopteris and
Heterangium. It is with such genera as Neuropteris, Alethopteris, Linopteris
and others that we are now more especially concerned, as they represent
some of the types of leaves borne by Medullosa and other members of the
Myeloxylon Landrioti bearing pinnules like those of Alethopteris aquilina
and A. Grandini.
Myeloxylon topekense (Penhallow).
The occurrence of Myeloxylon petioles in the New World was recorded
by the late Prof. Penhallow[288] who founded this species on some
imperfectly petrified specimens from Upper Carboniferous strata at Topeka,
Kansas. Enough material was available to show the Myeloxylon characters,
but the preservation is too imperfect to admit of a complete diagnosis. The
hypodermal stereome shows a tendency to form tangentially extended
strands in place of the more circular or radially elongated groups in the
European species.
In addition to Alethopteris, Neuropteris (including Cyclopteris) and
Odontopteris fronds, which are known to possess rachises with the
Myeloxylon features, there is reason to believe that the Permian Callipteris
fronds and possibly some of the older Taeniopteris leaves may also belong
to Medullosa[289]. It is, however, unsafe to assume that the occurrence of
Myeloxylon petioles necessarily denotes the existence of Medullosa. The
French stem Colpoxylon aeduense Brongn.[290] bore leaves with the same
general anatomical features as those of a typical Myeloxylon, and there can
be little doubt that other genera of the Medulloseae also possessed fronds
constructed on the same plan as those known to have been borne by
Medullosa. An interesting illustration of an injured organ that had produced
a wound-cambium is afforded by a Myeloxylon petiole from the Coal
Measures described by Mr Holden[291].
Reproductive Organs.
Reference was made in volume ii. to the reasons which led to the removal
of several genera of Carboniferous and Permian fronds from the Filicales to
the Pteridosperms, and in Chapter xxix. of the present volume certain
species of Sphenopteris are described as the foliage of Lyginopteris and
Heterangium. It is with such genera as Neuropteris, Alethopteris, Linopteris
and others that we are now more especially concerned, as they represent
some of the types of leaves borne by Medullosa and other members of the
Page 147
Medulloseae. The absence of any specimens among the large number of
these common genera bearing undoubted sporangia aroused suspicion as to
the correctness of the generally accepted view that these fern-like fossils
were the leaves of Palaeozoic Ferns. Subsequently the suspicion based on
negative evidence was confirmed by researches into the anatomical
structure of the leaf-bases, petioles, and fragments of pinnae attached to and
associated with stems of Medullosa. It is only in a few cases that actual
organic connexion between reproductive organs and Medullosan leaves has
been demonstrated, but from such facts as are established it is safe to make
the general statement that stems of Medullosa—a generic term that
undoubtedly includes plants which, had we a fuller knowledge of them as
complete individuals, would be assigned to more than one generic type—
possessed fronds simulating in habit those of certain Ferns with some of the
pinnae bearing seeds often of considerable size and in all cases of complex
structure, agreeing in many respects with those of existing Cycads, while
other fronds, or in some cases it may be other pinnae, bore microsporangia
similar in form to the sporangia of Ferns.
a. Microsporangia.
Neuropteris. A. Neuropteris heterophylla[292].
Several examples of supposed fertile specimens of Neuropteris are
recorded in palaeobotanical literature, but it was not until 1887 that any
satisfactory specimen was discovered. In that year Kidston[293] described a
specimen of Neuropteris heterophylla from the Lower Coal Measures of
Scotland in which slender forked branchlets bear small bodies at their tips
some of which appear to represent four-valved organs (fig. 421, D), though
the imperfect state of preservation renders impossible any definite
pronouncement as to their structure. To the specimen are attached a few
sterile pinnules, showing that it is a portion of a frond of N. heterophylla
characterised by the substitution of reproductive organs for pinnules. The
subsequent discovery of seeds attached to pinnae of the same species
afforded strong presumptive evidence, almost amounting to proof, of the
microsporangial nature of the Scotch specimen. For this specimen, although
no precise diagnosis is possible, Dr P. Bertrand[294] has proposed the generic
name Neurotheca. In 1911 the Abbé Carpentier[295] described some small
ovoid bodies, 1–1·5 mm. long, from the Coal Measures of France arranged
these common genera bearing undoubted sporangia aroused suspicion as to
the correctness of the generally accepted view that these fern-like fossils
were the leaves of Palaeozoic Ferns. Subsequently the suspicion based on
negative evidence was confirmed by researches into the anatomical
structure of the leaf-bases, petioles, and fragments of pinnae attached to and
associated with stems of Medullosa. It is only in a few cases that actual
organic connexion between reproductive organs and Medullosan leaves has
been demonstrated, but from such facts as are established it is safe to make
the general statement that stems of Medullosa—a generic term that
undoubtedly includes plants which, had we a fuller knowledge of them as
complete individuals, would be assigned to more than one generic type—
possessed fronds simulating in habit those of certain Ferns with some of the
pinnae bearing seeds often of considerable size and in all cases of complex
structure, agreeing in many respects with those of existing Cycads, while
other fronds, or in some cases it may be other pinnae, bore microsporangia
similar in form to the sporangia of Ferns.
a. Microsporangia.
Neuropteris. A. Neuropteris heterophylla[292].
Several examples of supposed fertile specimens of Neuropteris are
recorded in palaeobotanical literature, but it was not until 1887 that any
satisfactory specimen was discovered. In that year Kidston[293] described a
specimen of Neuropteris heterophylla from the Lower Coal Measures of
Scotland in which slender forked branchlets bear small bodies at their tips
some of which appear to represent four-valved organs (fig. 421, D), though
the imperfect state of preservation renders impossible any definite
pronouncement as to their structure. To the specimen are attached a few
sterile pinnules, showing that it is a portion of a frond of N. heterophylla
characterised by the substitution of reproductive organs for pinnules. The
subsequent discovery of seeds attached to pinnae of the same species
afforded strong presumptive evidence, almost amounting to proof, of the
microsporangial nature of the Scotch specimen. For this specimen, although
no precise diagnosis is possible, Dr P. Bertrand[294] has proposed the generic
name Neurotheca. In 1911 the Abbé Carpentier[295] described some small
ovoid bodies, 1–1·5 mm. long, from the Coal Measures of France arranged
Page 148
in groups of 4 to 6 and in some cases said to be borne on a slender pedicel
which he found in association with N. heterophylla and compared with
sporangia described by Lesquereux from the Coal Measures of Arkansas as
Sorocladus stellata[296]. These supposed microsporangia have recently been
assigned by Bertrand[297] to Sphenophyllum.
Fig. 421.
A. Potoniea adiantiformis Zeill. (very slightly enlarged).
B. Microsporangia of Potoniea (enlarged).
C. Linopteris obliqua; side-view of microsporophyll.
D. Neuropteris heterophylla, pinnules and microsporangia (?).
E. Linopteris obliqua, surface-view of microsporophyll.
(A, C, E, after P. Bertrand; B, after Carpentier; D, after Kidston.)
which he found in association with N. heterophylla and compared with
sporangia described by Lesquereux from the Coal Measures of Arkansas as
Sorocladus stellata[296]. These supposed microsporangia have recently been
assigned by Bertrand[297] to Sphenophyllum.
Fig. 421.
A. Potoniea adiantiformis Zeill. (very slightly enlarged).
B. Microsporangia of Potoniea (enlarged).
C. Linopteris obliqua; side-view of microsporophyll.
D. Neuropteris heterophylla, pinnules and microsporangia (?).
E. Linopteris obliqua, surface-view of microsporophyll.
(A, C, E, after P. Bertrand; B, after Carpentier; D, after Kidston.)
Page 149
B. Neuropteris gigantea, etc. Potoniea, Zeiller.
In 1899 Zeiller[298] instituted the name Potoniea for some peculiar fertile
leaves found in the Coal Measures of Heraclea consisting of a branched
axis with cuneate segments, 7–10 × 6–8 mm., bearing numerous fusiform
bodies, 1–1·5 mm. long, at the upper edge (fig. 421, A). These marginal
bodies he regarded as sporangia and expressed the opinion that Potoniea
may be the fructification of some form of Neuropteris, Mariopteris or
Alethopteris. Carpentier[299] afterwards described similar though rather
larger examples from the Pas-de-Calais coal-field as microsporophyll
fragments of some Pteridosperm: he stated that similar specimens had been
found by Kidston in England. In a later work Carpentier[300] described the
sporangia as crowded in groups (fig. 421, B) in the substance of the thick
lamina of Potoniea, and he connected the fertile segments with Neuropteris
gigantea, N. pseudogigantea Pot. and Linopteris obliqua (Bunb.). Similar
specimens are said to have been found in Holland and Silesia. Bertrand[301]
also records the association of Potoniea with Neuropteris gigantea and N.
pseudogigantea: he describes some specimens as belonging to N. gigantea
Sternb. while others, distinguished only by small differences, he attributes
to N. pseudogigantea. Kidston[302] has recently drawn attention to the
inconstancy of the characters mentioned by Potonié as distinguishing
features of N. pseudogigantea, and he shows good cause for referring the
examples so named to N. gigantea. The fertile lamina is almost orbicular in
surface-view and attached to a slightly excentric pedicel; the
microsporangia are borne on the lower surface and probably in groups as
described by Carpentier.
Neuropteris Carpentieri Kidston. Kidston[303] has recently described some
fertile leaflets under this name from the Westphalian series of South
Staffordshire which he identifies with French examples referred by
Carpentier[304] to Potoniea adiantiformis Zeill. The fertile pinnules are thick
and sub-cyclopteroid in form; the upper surface bears densely packed,
narrow and long, microsporangia, 4 × 0·5 mm., containing more or less
spherical microspores 45–60μ in diameter; the ventral face of the lamina on
the removal of the spores shows several strong veins. With these are
associated sterile pinnules of the Neuropteroid type, and examples are
described intermediate between the sterile and fertile leaflets. Kidston
believes the specimens to be microsporophylls of some species of
In 1899 Zeiller[298] instituted the name Potoniea for some peculiar fertile
leaves found in the Coal Measures of Heraclea consisting of a branched
axis with cuneate segments, 7–10 × 6–8 mm., bearing numerous fusiform
bodies, 1–1·5 mm. long, at the upper edge (fig. 421, A). These marginal
bodies he regarded as sporangia and expressed the opinion that Potoniea
may be the fructification of some form of Neuropteris, Mariopteris or
Alethopteris. Carpentier[299] afterwards described similar though rather
larger examples from the Pas-de-Calais coal-field as microsporophyll
fragments of some Pteridosperm: he stated that similar specimens had been
found by Kidston in England. In a later work Carpentier[300] described the
sporangia as crowded in groups (fig. 421, B) in the substance of the thick
lamina of Potoniea, and he connected the fertile segments with Neuropteris
gigantea, N. pseudogigantea Pot. and Linopteris obliqua (Bunb.). Similar
specimens are said to have been found in Holland and Silesia. Bertrand[301]
also records the association of Potoniea with Neuropteris gigantea and N.
pseudogigantea: he describes some specimens as belonging to N. gigantea
Sternb. while others, distinguished only by small differences, he attributes
to N. pseudogigantea. Kidston[302] has recently drawn attention to the
inconstancy of the characters mentioned by Potonié as distinguishing
features of N. pseudogigantea, and he shows good cause for referring the
examples so named to N. gigantea. The fertile lamina is almost orbicular in
surface-view and attached to a slightly excentric pedicel; the
microsporangia are borne on the lower surface and probably in groups as
described by Carpentier.
Neuropteris Carpentieri Kidston. Kidston[303] has recently described some
fertile leaflets under this name from the Westphalian series of South
Staffordshire which he identifies with French examples referred by
Carpentier[304] to Potoniea adiantiformis Zeill. The fertile pinnules are thick
and sub-cyclopteroid in form; the upper surface bears densely packed,
narrow and long, microsporangia, 4 × 0·5 mm., containing more or less
spherical microspores 45–60μ in diameter; the ventral face of the lamina on
the removal of the spores shows several strong veins. With these are
associated sterile pinnules of the Neuropteroid type, and examples are
described intermediate between the sterile and fertile leaflets. Kidston
believes the specimens to be microsporophylls of some species of
Page 150
Neuropteris, but as the material does not suffice for identification with any
known species a new name is proposed. It is pointed out that in some states
of preservation the leaflets resemble Goeppert’s Permian species
Dictyothalamus Schrollianus[305].
Alethopteris. Linopteris.
No specimens of Alethopteris fronds have so far been described that
afford any information as to the nature of the microsporangia, and we have
no means of knowing whether they were borne on naked pedicels as in
Neuropteris heterophylla, or on modified pinnules as in N. gigantea.
Zeiller in 1888[306] described some fertile pinnules of Dictyopteris
Schützii Roem. from Commentry bearing two rows of long sporangia: he
subsequently transferred this species to the genus Linopteris[307] and
expressed the opinion that the sporangia occur singly and not in groups as
he originally believed. Zeiller compares the fertile pinnules with the type
Crossotheca. Bertrand[308], as the result of examining similar specimens, has
suggested that the fringe of pendulous bodies regarded by Zeiller as
sporangia may be tooth-like lobes of modified pinnules which served to
protect microsporangia borne on the lower surface of the lamina. The nature
of the impressions is not clear, though there is little doubt that they are
microsporophylls. The fertile pinnae of Linopteris obliqua (Bunb.)
described by Carpentier[309] and Bertrand[310] closely resemble the
microspore-bearing organs which have been referred to Neuropteris
gigantea; they have the characters of Potoniea and consist of oval laminae
similar to the sterile pinnules but about half their size: the lamina was
attached excentrically to a slender stalk (fig. 421, C, E) and traversed by
numerous occasionally anastomosing veins. No actual microsporangia have
been discovered in organic connexion with the lamina.
b. Megasporangia.
Neuropteris.
Kidston’s discovery of undoubted seeds attached to pinnae of
Neuropteris[311] marked an important step in our more exact knowledge of
the morphology of Medullosan sporophylls. Specimens from the ironstone
balls (Coal Measures) of Coseley near Dudley showed seeds attached to
portions of pinnae bearing pinnules of Neuropteris heterophylla. The seeds
known species a new name is proposed. It is pointed out that in some states
of preservation the leaflets resemble Goeppert’s Permian species
Dictyothalamus Schrollianus[305].
Alethopteris. Linopteris.
No specimens of Alethopteris fronds have so far been described that
afford any information as to the nature of the microsporangia, and we have
no means of knowing whether they were borne on naked pedicels as in
Neuropteris heterophylla, or on modified pinnules as in N. gigantea.
Zeiller in 1888[306] described some fertile pinnules of Dictyopteris
Schützii Roem. from Commentry bearing two rows of long sporangia: he
subsequently transferred this species to the genus Linopteris[307] and
expressed the opinion that the sporangia occur singly and not in groups as
he originally believed. Zeiller compares the fertile pinnules with the type
Crossotheca. Bertrand[308], as the result of examining similar specimens, has
suggested that the fringe of pendulous bodies regarded by Zeiller as
sporangia may be tooth-like lobes of modified pinnules which served to
protect microsporangia borne on the lower surface of the lamina. The nature
of the impressions is not clear, though there is little doubt that they are
microsporophylls. The fertile pinnae of Linopteris obliqua (Bunb.)
described by Carpentier[309] and Bertrand[310] closely resemble the
microspore-bearing organs which have been referred to Neuropteris
gigantea; they have the characters of Potoniea and consist of oval laminae
similar to the sterile pinnules but about half their size: the lamina was
attached excentrically to a slender stalk (fig. 421, C, E) and traversed by
numerous occasionally anastomosing veins. No actual microsporangia have
been discovered in organic connexion with the lamina.
b. Megasporangia.
Neuropteris.
Kidston’s discovery of undoubted seeds attached to pinnae of
Neuropteris[311] marked an important step in our more exact knowledge of
the morphology of Medullosan sporophylls. Specimens from the ironstone
balls (Coal Measures) of Coseley near Dudley showed seeds attached to
portions of pinnae bearing pinnules of Neuropteris heterophylla. The seeds
Page 151
are approximately 3 cm. long and from 1·10 to 1·40 cm. broad; oblong and
gradually tapering from the middle to a slightly curved and obtuse apical
snout (fig. 422). The outer surface shows numerous longitudinal ribs which
no doubt represent hypodermal fibres. The preservation of the seeds, which
appear to be circular in section, is not such as to render possible a
description of structural features. In their asymmetrical form the seeds agree
with the genus Platyspermum as recently defined by Arber, but Kidston’s
specimens are in all probability radiospermic. Kidston compares the
Neuropteris seeds with Rhabdocarpus tunicatus as figured from the
Commentry coalfield[312] and with specimens from Gard named by
Grand’Eury R. subtunicatus[313].
gradually tapering from the middle to a slightly curved and obtuse apical
snout (fig. 422). The outer surface shows numerous longitudinal ribs which
no doubt represent hypodermal fibres. The preservation of the seeds, which
appear to be circular in section, is not such as to render possible a
description of structural features. In their asymmetrical form the seeds agree
with the genus Platyspermum as recently defined by Arber, but Kidston’s
specimens are in all probability radiospermic. Kidston compares the
Neuropteris seeds with Rhabdocarpus tunicatus as figured from the
Commentry coalfield[312] and with specimens from Gard named by
Grand’Eury R. subtunicatus[313].
Page 152
Fig. 422. Neuropterocarpus Kidstoni (Arber). (After Kidston; × 3.)
Additional proof of the occurrence of seeds on Neuropteris fronds is
furnished by examples from the Coal Measures of Holland described by
Kidston and Jongmans[314]: these seeds are of the same general type as those
from Coseley but nearly twice as large, and they were borne at the tips of a
dichotomously branched pedicel of Neuropteris obliqua. Grand’Eury in
1904[315] recorded the association of radiospermic seeds with Neuropteris
fronds though no case of actual attachment was found. It is, however,
noteworthy that he speaks of the frequent association with Neuropteris of
Additional proof of the occurrence of seeds on Neuropteris fronds is
furnished by examples from the Coal Measures of Holland described by
Kidston and Jongmans[314]: these seeds are of the same general type as those
from Coseley but nearly twice as large, and they were borne at the tips of a
dichotomously branched pedicel of Neuropteris obliqua. Grand’Eury in
1904[315] recorded the association of radiospermic seeds with Neuropteris
fronds though no case of actual attachment was found. It is, however,
noteworthy that he speaks of the frequent association with Neuropteris of
Page 153
seeds characterised by six or rarely twelve longitudinal keels, a feature
recalling the sclerotesta of Trigonocarpus and allied seeds. Until petrified
specimens are available it is impossible to refer the seeds of Neuropteris to
a generic type founded on structural features: the seeds described by
Kidston are, as he says, very similar in external characters to species
assigned to Rhabdocarpus, and there can be little doubt as to the generic
identity of the Neuropteris seeds and some of the impressions referred to
Rhabdocarpus which are characterised by a similarity in form, an apical
snout that gives an asymmetrical appearance to the specimens and the
presence of numerous longitudinal striations[316]. It is, however, by no means
certain that these seeds possessed the morphological features of
Rhabdocarpus as described by Brongniart in petrified examples from St
Étienne[317].
The seeds of Neuropteris may, as Kidston suggests, agree anatomically
more closely with Pachytesta[318], a type that Grand’Eury associates with
Alethopteris fronds. With a view to avoid the danger of incorrectly
identifying petrified specimens and impressions that cannot be proved to
belong to the same generic type, I have suggested the restriction of the
name Rhabdocarpus[319] to seeds that do not furnish evidence as to internal
structure, and the employment of the designation Rhabdospermum for seeds
that conform to those described by Brongniart as Rhabdocarpus. The seeds
of Neuropteris may be of the Rhabdospermum type or they may agree
anatomically more closely with Trigonocarpus or Pachytesta; they are
members of either the Trigonocarpales or the Cardiocarpales, probably the
former group. Dr P. Bertrand[320] assigns to Neuropteris gigantea some seeds
of the Hexapterospermum (= Hexagonocarpus[321]) type which occur in
association with cupule-like organs. These supposed cupules resemble the
Potoniea leaflets with microsporangia also referred to the same species of
Neuropteris; they are characterised by a laciniate edge and may be
compared with the Indian fossil described by Zeiller as Ottokaria
bengalensis[322] (fig. 433). Dr Arber[323] and Dr P. Bertrand[324] have
independently proposed the generic name Neurospermum for the seeds of
Neuropteris heterophylla and N. obliqua in preference to Rhabdocarpus: the
former author speaks of the seeds of N. heterophylla as Neurospermum
Kidstoni. The generic term Neuropterocarpus used by Grand’Eury in
1904[325], though not defined by him, has priority and avoids the adoption of
a new designation for seeds attached to Neuropteris fronds. In his definition
recalling the sclerotesta of Trigonocarpus and allied seeds. Until petrified
specimens are available it is impossible to refer the seeds of Neuropteris to
a generic type founded on structural features: the seeds described by
Kidston are, as he says, very similar in external characters to species
assigned to Rhabdocarpus, and there can be little doubt as to the generic
identity of the Neuropteris seeds and some of the impressions referred to
Rhabdocarpus which are characterised by a similarity in form, an apical
snout that gives an asymmetrical appearance to the specimens and the
presence of numerous longitudinal striations[316]. It is, however, by no means
certain that these seeds possessed the morphological features of
Rhabdocarpus as described by Brongniart in petrified examples from St
Étienne[317].
The seeds of Neuropteris may, as Kidston suggests, agree anatomically
more closely with Pachytesta[318], a type that Grand’Eury associates with
Alethopteris fronds. With a view to avoid the danger of incorrectly
identifying petrified specimens and impressions that cannot be proved to
belong to the same generic type, I have suggested the restriction of the
name Rhabdocarpus[319] to seeds that do not furnish evidence as to internal
structure, and the employment of the designation Rhabdospermum for seeds
that conform to those described by Brongniart as Rhabdocarpus. The seeds
of Neuropteris may be of the Rhabdospermum type or they may agree
anatomically more closely with Trigonocarpus or Pachytesta; they are
members of either the Trigonocarpales or the Cardiocarpales, probably the
former group. Dr P. Bertrand[320] assigns to Neuropteris gigantea some seeds
of the Hexapterospermum (= Hexagonocarpus[321]) type which occur in
association with cupule-like organs. These supposed cupules resemble the
Potoniea leaflets with microsporangia also referred to the same species of
Neuropteris; they are characterised by a laciniate edge and may be
compared with the Indian fossil described by Zeiller as Ottokaria
bengalensis[322] (fig. 433). Dr Arber[323] and Dr P. Bertrand[324] have
independently proposed the generic name Neurospermum for the seeds of
Neuropteris heterophylla and N. obliqua in preference to Rhabdocarpus: the
former author speaks of the seeds of N. heterophylla as Neurospermum
Kidstoni. The generic term Neuropterocarpus used by Grand’Eury in
1904[325], though not defined by him, has priority and avoids the adoption of
a new designation for seeds attached to Neuropteris fronds. In his definition
Page 154
of Neurospermum Arber makes no reference to the obliquity of the apical
snout that is clearly shown in fig. 422. There is no evidence that
Neuropterocarpus possessed a cupular investment comparable with that of
Lagenostoma. Additional instances of the association of seeds with
Neuropteris fronds are recorded by Renier from the Belgian Coal Measures,
also by Bertrand and Chodat from France: Renier found seeds associated
with N. Schlehani Stur and with the same species of frond Bertrand found
impressions of oval ribbed seeds. Prof. Chodat[326] has figured some
fragments of Neuropteris pinnules referred to N. auriculata Brongn. from
the Stephanian of France which show small seed-like bodies apparently in
organic connexion with the lamina; but the specimens are too imperfect to
afford any satisfactory evidence as to the nature of the reproductive organs.
Lotsy[327] has expressed the opinion that the bodies attached to
Neuropteris pinnae described by Kidston and other authors as seeds may
possibly be vegetative buds, but if this were the case one would expect to
find some evidence of the bud-nature in some at least of the specimens that
have already been found.
It would seem that the microsporophylls of Neuropteris were constructed
on different plans, some being of the type described by Zeiller and other
observers as Potoniea, while others bore sporangia on pinnae without any
accompanying laminae; but our knowledge of the latter form represented by
Kidston’s specimen of Neuropteris heterophylla (fig. 421, D) is very
incomplete. On the other hand the seeds appear to have been characterised
by features suggesting a close affinity to Trigonocarpus and pointing to
membership of the same family.
Alethopteris.
Although no specimens have been discovered showing actual connexion
between fronds and seeds, it is practically certain that Alethopteris leaves,
or at least some species of the genus, bore seeds of the Trigonocarpus type.
The association of Trigonocarpus Parkinsoni with Alethopteris lonchitica is
too frequent to be fortuitous and there is further evidence afforded by
certain anatomical resemblances. In France other species of Alethopteris,
e.g. Alethopteris Serlii and A. Grandini, occur in association with
Pachytesta[328], a large seed similar to Trigonocarpus, and Trigonocarpus is
found in the Pas-de-Calais coal-field with Alethopteris Serlii.
snout that is clearly shown in fig. 422. There is no evidence that
Neuropterocarpus possessed a cupular investment comparable with that of
Lagenostoma. Additional instances of the association of seeds with
Neuropteris fronds are recorded by Renier from the Belgian Coal Measures,
also by Bertrand and Chodat from France: Renier found seeds associated
with N. Schlehani Stur and with the same species of frond Bertrand found
impressions of oval ribbed seeds. Prof. Chodat[326] has figured some
fragments of Neuropteris pinnules referred to N. auriculata Brongn. from
the Stephanian of France which show small seed-like bodies apparently in
organic connexion with the lamina; but the specimens are too imperfect to
afford any satisfactory evidence as to the nature of the reproductive organs.
Lotsy[327] has expressed the opinion that the bodies attached to
Neuropteris pinnae described by Kidston and other authors as seeds may
possibly be vegetative buds, but if this were the case one would expect to
find some evidence of the bud-nature in some at least of the specimens that
have already been found.
It would seem that the microsporophylls of Neuropteris were constructed
on different plans, some being of the type described by Zeiller and other
observers as Potoniea, while others bore sporangia on pinnae without any
accompanying laminae; but our knowledge of the latter form represented by
Kidston’s specimen of Neuropteris heterophylla (fig. 421, D) is very
incomplete. On the other hand the seeds appear to have been characterised
by features suggesting a close affinity to Trigonocarpus and pointing to
membership of the same family.
Alethopteris.
Although no specimens have been discovered showing actual connexion
between fronds and seeds, it is practically certain that Alethopteris leaves,
or at least some species of the genus, bore seeds of the Trigonocarpus type.
The association of Trigonocarpus Parkinsoni with Alethopteris lonchitica is
too frequent to be fortuitous and there is further evidence afforded by
certain anatomical resemblances. In France other species of Alethopteris,
e.g. Alethopteris Serlii and A. Grandini, occur in association with
Pachytesta[328], a large seed similar to Trigonocarpus, and Trigonocarpus is
found in the Pas-de-Calais coal-field with Alethopteris Serlii.
Page 155
TRIGONOCARPUS. Brongniart.
The generic name Trigonocarpum was instituted by Brongniart in
1828[329] for ovoid longitudinally ribbed ‘fruits’ from Upper Carboniferous
strata, the type-species being named T. Parkinsoni. The generic name is
often altered to Trigonocarpon: Williamson[330], who adopted this form,
states that Brongniart substituted Trigonocarpon for Trigonocarpum in his
Tableau[331], but in that work the original termination is used, the form
Trigonocarpon, probably the result of a slip, appearing only in the index. In
his later work on seeds Brongniart adopted the name Trigonocarpus, and in
recent years this has been widely employed. Among other species named by
Brongniart are two previously referred by Sternberg to Palmacites. Several
examples of Brongniart’s genus were described by Lindley and Hutton, and
in their description of T. Noeggerathii the statement is made that a fractured
specimen demonstrated that ‘the fossil in its ordinary state is an interior part
divested of fleshy covering’[332]; this suspicion of the true nature of the nut-
like fossils was afterwards proved correct by the investigations of Hooker
and Binney[333] and by the later work of Williamson. The specimens on
which the genus was founded are casts of seed-cavities and it is in this state
that the seeds are usually preserved, often in large numbers, in the
sandstones of the Coal Measures, as in the block shown in fig. 423 from the
famous quarry at Peel near Bolton, Lancashire. Another type of
preservation is represented by the seeds figured by Lindley and Hutton as
Carpolithes alata[334], but the generic identity of the two states was not
recognised until the discovery of petrified material afforded the clue. Figs.
424, 1, 425 illustrate the appearance of Trigonocarpus when preserved as a
carbonised impression showing a thick fleshy envelope enclosing an oval
kernel with a hard wall prolonged upwards as a longer or shorter micropyle.
Casts of the seed-cavity are represented in figs. 423; 424, 2, 3. The surface
of these casts occasionally shows one or more short cylindrical projections
which are probably extensions of the sand or mud into holes formed in the
testa by boring insects. The view that Trigonocarpus seeds are ‘obviously
Palm fruits’ was not accepted by Hooker and Binney who inclined to regard
them as the seeds of Conifers and compared them especially with the
similar nuts of Ginkgo seeds (cf. fig. 631, C). It was Mr Wild[335] who was
first struck by the association of Trigonocarpus and the petioles of
Medullosa (Myeloxylon) and by some resemblances in structure between
the testa and the hypoderm of the petioles; though, as Scott and Maslen[336]
The generic name Trigonocarpum was instituted by Brongniart in
1828[329] for ovoid longitudinally ribbed ‘fruits’ from Upper Carboniferous
strata, the type-species being named T. Parkinsoni. The generic name is
often altered to Trigonocarpon: Williamson[330], who adopted this form,
states that Brongniart substituted Trigonocarpon for Trigonocarpum in his
Tableau[331], but in that work the original termination is used, the form
Trigonocarpon, probably the result of a slip, appearing only in the index. In
his later work on seeds Brongniart adopted the name Trigonocarpus, and in
recent years this has been widely employed. Among other species named by
Brongniart are two previously referred by Sternberg to Palmacites. Several
examples of Brongniart’s genus were described by Lindley and Hutton, and
in their description of T. Noeggerathii the statement is made that a fractured
specimen demonstrated that ‘the fossil in its ordinary state is an interior part
divested of fleshy covering’[332]; this suspicion of the true nature of the nut-
like fossils was afterwards proved correct by the investigations of Hooker
and Binney[333] and by the later work of Williamson. The specimens on
which the genus was founded are casts of seed-cavities and it is in this state
that the seeds are usually preserved, often in large numbers, in the
sandstones of the Coal Measures, as in the block shown in fig. 423 from the
famous quarry at Peel near Bolton, Lancashire. Another type of
preservation is represented by the seeds figured by Lindley and Hutton as
Carpolithes alata[334], but the generic identity of the two states was not
recognised until the discovery of petrified material afforded the clue. Figs.
424, 1, 425 illustrate the appearance of Trigonocarpus when preserved as a
carbonised impression showing a thick fleshy envelope enclosing an oval
kernel with a hard wall prolonged upwards as a longer or shorter micropyle.
Casts of the seed-cavity are represented in figs. 423; 424, 2, 3. The surface
of these casts occasionally shows one or more short cylindrical projections
which are probably extensions of the sand or mud into holes formed in the
testa by boring insects. The view that Trigonocarpus seeds are ‘obviously
Palm fruits’ was not accepted by Hooker and Binney who inclined to regard
them as the seeds of Conifers and compared them especially with the
similar nuts of Ginkgo seeds (cf. fig. 631, C). It was Mr Wild[335] who was
first struck by the association of Trigonocarpus and the petioles of
Medullosa (Myeloxylon) and by some resemblances in structure between
the testa and the hypoderm of the petioles; though, as Scott and Maslen[336]
Page 156
point out, the agreement is not so close as Wild believed, his view of a
possible connexion between the reproductive and vegetative organs has
been confirmed. Williamson extended our knowledge of the genus by his
account of Trigonocarpus olivaeformis Lind. and Hutt., a form that is
specifically identical with T. Parkinsoni Brongn. This author also drew
attention to the close resemblance between Brongniart’s three genera
Trigonocarpus, Hexapterospermum, Tripterospermum and expressed doubts
as to the possibility of founding specific differences on casts of the
Trigonocarpus type without the evidence of anatomy. Our knowledge of the
structure of Trigonocarpus has in recent years been considerably extended
by the researches of Oliver, Scott and Maslen, and Salisbury.
Fig. 423. Casts of the seed-cavity of Trigonocarpus Parkinsoni.
(Manchester Museum. ½ nat. size.)
Trigonocarpus Parkinsoni[337] Brongniart.
The seeds of this species like all examples of the genus are radiospermic,
that is radially symmetrical in contrast to the flattened or platyspermic
seeds. The complete seed is elongate oval in form when preserved as an
impression (fig. 425, A) and reaches a length of 4–5 cm.: the casts of the
seed-cavity are ovoid and provided with three prominent ridges (fig. 424, 2,
3). The testa forms a thick covering differentiated into three regions, an
outer flesh or sarcotesta, a sclerous shell or sclerotesta, and an inner flesh.
Transverse sections show that the sclerotesta has three sharp longitudinal
keels with corresponding furrows on the inner face, and between each pair
of main ribs are 2–3 less prominent ridges, usually 12 in all (fig. 426). The
possible connexion between the reproductive and vegetative organs has
been confirmed. Williamson extended our knowledge of the genus by his
account of Trigonocarpus olivaeformis Lind. and Hutt., a form that is
specifically identical with T. Parkinsoni Brongn. This author also drew
attention to the close resemblance between Brongniart’s three genera
Trigonocarpus, Hexapterospermum, Tripterospermum and expressed doubts
as to the possibility of founding specific differences on casts of the
Trigonocarpus type without the evidence of anatomy. Our knowledge of the
structure of Trigonocarpus has in recent years been considerably extended
by the researches of Oliver, Scott and Maslen, and Salisbury.
Fig. 423. Casts of the seed-cavity of Trigonocarpus Parkinsoni.
(Manchester Museum. ½ nat. size.)
Trigonocarpus Parkinsoni[337] Brongniart.
The seeds of this species like all examples of the genus are radiospermic,
that is radially symmetrical in contrast to the flattened or platyspermic
seeds. The complete seed is elongate oval in form when preserved as an
impression (fig. 425, A) and reaches a length of 4–5 cm.: the casts of the
seed-cavity are ovoid and provided with three prominent ridges (fig. 424, 2,
3). The testa forms a thick covering differentiated into three regions, an
outer flesh or sarcotesta, a sclerous shell or sclerotesta, and an inner flesh.
Transverse sections show that the sclerotesta has three sharp longitudinal
keels with corresponding furrows on the inner face, and between each pair
of main ribs are 2–3 less prominent ridges, usually 12 in all (fig. 426). The
Page 157
sarcotesta consists of thin-walled parenchyma passing externally into a
more lacunar tissue with a palisade-like hypoderm: the sclerotesta consists
of thick cells which interlace and form an efficient protective shell. Both the
sarcotesta and sclerotesta are continued into the apical region as the wall of
the long micropyle, the sarcotesta being prolonged beyond the sclerotesta at
the apex of the integument[338]. The micropyle is triangular in section and
may exceed in length the whole seed (figs. 425; 426, A). Its form as seen in
transverse section (fig. 426, B) suggests the presence of wings: this
appearance may be deceptive and due to pressure or, more probably, it
represents an original feature. The seed-body, that is the portion enclosed by
the integument, consists of the nucellus, represented by a few crushed
layers of cells, bounded by a well-defined epidermis; the nucellus is
separated from the integument from the base of the seed upwards, an
important feature in which this and some other Palaeozoic seeds differ from
Lagenostoma and the seeds of recent Cycads which are characterised by an
integument adnate to the nucellus up to the level of the shoulder; the seeds
of the Conifer Phyllocladus afford an example of separation of integument
and nucellus as in Trigonocarpus. The innermost layer of the nucellus
consists mainly of tracheal tissue investing the large megaspore (fig. 426, A,
C, m) which is preserved as a contracted membrane detached from the
nucellus after the death of the seed. At the summit of the nucellus is a
relatively small pollen-chamber (fig. 426, A, Pc) like a broad and low
cupola bearing a terminal beak which extended some distance into the
micropylar tube. No microspores have been found in this species, but
Oliver[339] records the occurrence of multicellular microspores in
Trigonocarpus pusillus. The pedicel of the seed had a central strand of
sclerous tissue penetrated by a concentric vascular bundle which gives off
six strands to supply the sarcotesta (fig. 426, C, v) and then passes into the
nucellus where it forms a tracheal sheath (fig. 426, A, nt) surrounding the
lower part of the megaspore and at a higher level breaks up into
anastomosing strands of tracheids which reach up to the plane of insertion
of the pollen-chamber.
more lacunar tissue with a palisade-like hypoderm: the sclerotesta consists
of thick cells which interlace and form an efficient protective shell. Both the
sarcotesta and sclerotesta are continued into the apical region as the wall of
the long micropyle, the sarcotesta being prolonged beyond the sclerotesta at
the apex of the integument[338]. The micropyle is triangular in section and
may exceed in length the whole seed (figs. 425; 426, A). Its form as seen in
transverse section (fig. 426, B) suggests the presence of wings: this
appearance may be deceptive and due to pressure or, more probably, it
represents an original feature. The seed-body, that is the portion enclosed by
the integument, consists of the nucellus, represented by a few crushed
layers of cells, bounded by a well-defined epidermis; the nucellus is
separated from the integument from the base of the seed upwards, an
important feature in which this and some other Palaeozoic seeds differ from
Lagenostoma and the seeds of recent Cycads which are characterised by an
integument adnate to the nucellus up to the level of the shoulder; the seeds
of the Conifer Phyllocladus afford an example of separation of integument
and nucellus as in Trigonocarpus. The innermost layer of the nucellus
consists mainly of tracheal tissue investing the large megaspore (fig. 426, A,
C, m) which is preserved as a contracted membrane detached from the
nucellus after the death of the seed. At the summit of the nucellus is a
relatively small pollen-chamber (fig. 426, A, Pc) like a broad and low
cupola bearing a terminal beak which extended some distance into the
micropylar tube. No microspores have been found in this species, but
Oliver[339] records the occurrence of multicellular microspores in
Trigonocarpus pusillus. The pedicel of the seed had a central strand of
sclerous tissue penetrated by a concentric vascular bundle which gives off
six strands to supply the sarcotesta (fig. 426, C, v) and then passes into the
nucellus where it forms a tracheal sheath (fig. 426, A, nt) surrounding the
lower part of the megaspore and at a higher level breaks up into
anastomosing strands of tracheids which reach up to the plane of insertion
of the pollen-chamber.
Page 158
Fig. 424. Trigonocarpus. 1. Section of imperfect seed showing a
micropyle; b, sclerotesta; c, cast of seed-cavity; 2, 3, apical and
basal view of seed-cast. (Approximately nat. size.) M. S.
micropyle; b, sclerotesta; c, cast of seed-cavity; 2, 3, apical and
basal view of seed-cast. (Approximately nat. size.) M. S.
Page 159
Fig. 425. Trigonocarpus Parkinsoni.
A. Impression showing the nucule and sarcotesta. (= Carpolithes
alata Lind. and Hutt.)
B. Specimen with long micropyle. (A, nat. size; from the Lower
Coal Measures of Kilmarnock; B, nat. size; Middle C. M. of
Yorkshire. Kidston Coll., 1579 and 1062.)
A. Impression showing the nucule and sarcotesta. (= Carpolithes
alata Lind. and Hutt.)
B. Specimen with long micropyle. (A, nat. size; from the Lower
Coal Measures of Kilmarnock; B, nat. size; Middle C. M. of
Yorkshire. Kidston Coll., 1579 and 1062.)
Page 160
Fig. 426. Trigonocarpus Parkinsoni. A, longitudinal section; Sa, Sc, if,
sarcotesta, sclerotesta, inner flesh; mi, micropyle; Pc, pollen-
chamber; v, vascular bundles; m, megaspore and prothallus; t,
tracheal disc; nt, tracheids in the nucellus. B, transverse section of
the upper region showing the sarcotesta, sclerotesta (black) and
the micropyle. C, transverse section of T. Parkinsoni. D, transverse
section of Trigonocarpus shorensis. (A, C, after Scott; B, after
Wild; D, after Salisbury.)
sarcotesta, sclerotesta, inner flesh; mi, micropyle; Pc, pollen-
chamber; v, vascular bundles; m, megaspore and prothallus; t,
tracheal disc; nt, tracheids in the nucellus. B, transverse section of
the upper region showing the sarcotesta, sclerotesta (black) and
the micropyle. C, transverse section of T. Parkinsoni. D, transverse
section of Trigonocarpus shorensis. (A, C, after Scott; B, after
Wild; D, after Salisbury.)
Page 161
A second species described by Scott and Maslen as Trigonocarpus
Oliveri has been further investigated by Salisbury who finds that it is an 8-
angled seed which cannot be retained in the genus Trigonocarpus: its
systematic position ‘must for the present remain uncertain[340].’ Dr Arber has
recently described a new species of Trigonocarpus, T. Moyseyi[341], from the
Nottingham Coal-field (Middle Coal Measures), similar to T. Parkinsoni
but much broader in proportion to its length: this species is founded on an
impression without structure.
The species Trigonocarpus Dawesi Lind. and Hutt.[342], from the Middle
Coal Measures of Lancashire, was founded on casts differing in their large
dimensions from those of T. Parkinsoni: specimens referred to this species
were described by Fiedler[343] from Saxony in 1857 and Lesquereux[344]
figures similar casts from the Upper Carboniferous and Permian rocks of
North America.
Trigonocarpus shorensis Salisbury.
This species, founded on specimens from the Lower Coal Measures of
Shore, Lancashire[345], may exceed 4 cm. in length and has a breadth of 2·5
cm. In general plan it agrees with T. Parkinsoni but there are certain well-
marked differences: the micropyle is much shorter; the thick sarcotesta,
attaining a breadth of 6 mm. at the base of the micropyle, is characterised
by the presence of six peripherally placed vascular bundles (fig. 426, D, v)
in contrast to the deeply embedded bundles of T. Parkinsoni. Below the
epidermis of the sarcotesta is a hypoderm formed of radially disposed plates
of sclerous tissue similar to that of Myeloxylon and different from the
palisade-like hypoderm of the type-species. Within the sarcotesta is a hard
shell, the sclerotesta, characterised by three prominent ribs extending from
base to apex and three shorter ribs which reach from the chalaza to about a
third of the length of the seed. The fact that the sarcotesta and sclerotesta
pass gradually into one another is a point in favour of the view that the
integument is a single structure. There appears to be good evidence of the
restriction of an inner flesh to the micropylar region, whereas this tissue in
T. Parkinsoni was probably continuous over the whole inner face of the
sclerotesta. The sarcotesta is lacunar in its outer part as in some other types
of Palaeozoic seeds, a feature probably connected with floating efficiency.
Trigonocarpus shorensis occurs in association with Myeloxylon petioles,
Oliveri has been further investigated by Salisbury who finds that it is an 8-
angled seed which cannot be retained in the genus Trigonocarpus: its
systematic position ‘must for the present remain uncertain[340].’ Dr Arber has
recently described a new species of Trigonocarpus, T. Moyseyi[341], from the
Nottingham Coal-field (Middle Coal Measures), similar to T. Parkinsoni
but much broader in proportion to its length: this species is founded on an
impression without structure.
The species Trigonocarpus Dawesi Lind. and Hutt.[342], from the Middle
Coal Measures of Lancashire, was founded on casts differing in their large
dimensions from those of T. Parkinsoni: specimens referred to this species
were described by Fiedler[343] from Saxony in 1857 and Lesquereux[344]
figures similar casts from the Upper Carboniferous and Permian rocks of
North America.
Trigonocarpus shorensis Salisbury.
This species, founded on specimens from the Lower Coal Measures of
Shore, Lancashire[345], may exceed 4 cm. in length and has a breadth of 2·5
cm. In general plan it agrees with T. Parkinsoni but there are certain well-
marked differences: the micropyle is much shorter; the thick sarcotesta,
attaining a breadth of 6 mm. at the base of the micropyle, is characterised
by the presence of six peripherally placed vascular bundles (fig. 426, D, v)
in contrast to the deeply embedded bundles of T. Parkinsoni. Below the
epidermis of the sarcotesta is a hypoderm formed of radially disposed plates
of sclerous tissue similar to that of Myeloxylon and different from the
palisade-like hypoderm of the type-species. Within the sarcotesta is a hard
shell, the sclerotesta, characterised by three prominent ribs extending from
base to apex and three shorter ribs which reach from the chalaza to about a
third of the length of the seed. The fact that the sarcotesta and sclerotesta
pass gradually into one another is a point in favour of the view that the
integument is a single structure. There appears to be good evidence of the
restriction of an inner flesh to the micropylar region, whereas this tissue in
T. Parkinsoni was probably continuous over the whole inner face of the
sclerotesta. The sarcotesta is lacunar in its outer part as in some other types
of Palaeozoic seeds, a feature probably connected with floating efficiency.
Trigonocarpus shorensis occurs in association with Myeloxylon petioles,
Page 162
and there is a resemblance between the seed and the vegetative organs in
the structure of the hypoderm as also in the structure of the secretory sacs
which are particularly numerous in this species. Salisbury draws attention to
the close resemblance between the form of T. shorensis and the seeds found
in organic connexion with pinnae of Neuropteris obliqua[346].
The species T. corrugatus described by Renault[347] bears a close
resemblance to T. shorensis.
Other Genera founded in part on Reproductive Organs which may belong
to the Medulloseae.
Codonotheca, Schützia, Whittleseya, Dolerophyllum, Ottokaria,
Strobilites.
CODONOTHECA. Sellards.
Codonotheca caduca Sellards. This genus was founded on some spore-
bearing bodies from the Coal Measures of Illinois[348]: nothing is known as
to the plant which bore them, but Sellards is inclined to associate them with
Neuropteris decipiens Lesq.[349], a species abundant in the same coal-field.
Whatever may have been the parent-plant it is probable, as the author of the
genus believes, that Codonotheca is the microspore-bearing organ of a
Pteridosperm. As shown in fig. 427, 5, the form is that of a stalked cup
consisting in the basal portion of a stout axis, the peripheral tissue of which
is believed to have been fleshy, containing an axial rod of conducting tissue
running up to the floor of the cup, c, and then dividing into six vascular
strands, each of which forks into two branches. The upper part is composed
of six linear segments united basally to form the sloping surface of the cup.
On the inner face of each segment is a more or less well-defined depression
covered with large elliptical spores ·29–·31 mm. long by ·18–·19 mm.
broad (fig. 427, 6, 8). The presence of a median ridge (fig. 427, 8) indicates
a bilateral origin. ‘There is no grouping of the spores or other indication of
the location of the sporangia, which were doubtless more or less completely
immersed in the tissue, the dividing wall disappearing at maturity.’ The
spores are seen in fig. 427, 2, 3, on the inner face of the lobes. Some of the
specimens have a fairly long pedicel: in the example shown in fig. 427, 1,
the fleshy part of the basal portion is not preserved, only the more resistant
the structure of the hypoderm as also in the structure of the secretory sacs
which are particularly numerous in this species. Salisbury draws attention to
the close resemblance between the form of T. shorensis and the seeds found
in organic connexion with pinnae of Neuropteris obliqua[346].
The species T. corrugatus described by Renault[347] bears a close
resemblance to T. shorensis.
Other Genera founded in part on Reproductive Organs which may belong
to the Medulloseae.
Codonotheca, Schützia, Whittleseya, Dolerophyllum, Ottokaria,
Strobilites.
CODONOTHECA. Sellards.
Codonotheca caduca Sellards. This genus was founded on some spore-
bearing bodies from the Coal Measures of Illinois[348]: nothing is known as
to the plant which bore them, but Sellards is inclined to associate them with
Neuropteris decipiens Lesq.[349], a species abundant in the same coal-field.
Whatever may have been the parent-plant it is probable, as the author of the
genus believes, that Codonotheca is the microspore-bearing organ of a
Pteridosperm. As shown in fig. 427, 5, the form is that of a stalked cup
consisting in the basal portion of a stout axis, the peripheral tissue of which
is believed to have been fleshy, containing an axial rod of conducting tissue
running up to the floor of the cup, c, and then dividing into six vascular
strands, each of which forks into two branches. The upper part is composed
of six linear segments united basally to form the sloping surface of the cup.
On the inner face of each segment is a more or less well-defined depression
covered with large elliptical spores ·29–·31 mm. long by ·18–·19 mm.
broad (fig. 427, 6, 8). The presence of a median ridge (fig. 427, 8) indicates
a bilateral origin. ‘There is no grouping of the spores or other indication of
the location of the sporangia, which were doubtless more or less completely
immersed in the tissue, the dividing wall disappearing at maturity.’ The
spores are seen in fig. 427, 2, 3, on the inner face of the lobes. Some of the
specimens have a fairly long pedicel: in the example shown in fig. 427, 1,
the fleshy part of the basal portion is not preserved, only the more resistant
Page 163
vascular core. In a later account of these organs Sellards speaks of several
lying by the side of a central stalk to which he thinks they were originally
attached by slender pedicels. In view of Dr Benson’s interpretation of the
morphology of Telangium it is permissible to suggest that if a central
sporangium in such a synangium as that of Codonotheca developed a
megaspore and the peripheral sporogenous lobes were sterilised, the result
would be an arrangement not unlike the apical region of the seed
Physostoma, the tentacles of which have been homologised with the canopy
of Lagenostoma. There are obvious difficulties in the way of this, perhaps
strained, comparison: the larger size of the spore-bearing linear segments of
Codonotheca led Sellards to regard each as a synangium rather than a single
sporangium. But precise information as to the structure of the American
fossils is not as yet available. If the association of Codonotheca with
Neuropteris fronds has any significance it would favour a reference of these
organs to the Medulloseae. In the absence of anatomical data it is
impossible in some cases to distinguish microspore-bearing organs of the
Codonotheca type from small seeds enclosed in a lobed cupule or even
seeds with a lobed integument: a case in point is the New Brunswick
species Pterispermostrobus bifurcatus Stopes[350].
lying by the side of a central stalk to which he thinks they were originally
attached by slender pedicels. In view of Dr Benson’s interpretation of the
morphology of Telangium it is permissible to suggest that if a central
sporangium in such a synangium as that of Codonotheca developed a
megaspore and the peripheral sporogenous lobes were sterilised, the result
would be an arrangement not unlike the apical region of the seed
Physostoma, the tentacles of which have been homologised with the canopy
of Lagenostoma. There are obvious difficulties in the way of this, perhaps
strained, comparison: the larger size of the spore-bearing linear segments of
Codonotheca led Sellards to regard each as a synangium rather than a single
sporangium. But precise information as to the structure of the American
fossils is not as yet available. If the association of Codonotheca with
Neuropteris fronds has any significance it would favour a reference of these
organs to the Medulloseae. In the absence of anatomical data it is
impossible in some cases to distinguish microspore-bearing organs of the
Codonotheca type from small seeds enclosed in a lobed cupule or even
seeds with a lobed integument: a case in point is the New Brunswick
species Pterispermostrobus bifurcatus Stopes[350].
Page 164
Fig. 427. Codonotheca caduca. 1. The vascular tissue preserved as a
conical base which was originally surrounded by fleshy tissue (cf.
5); I–III, VI, vascular bundles (× 2). 2, 3. Segments with spores; c,
floor of cup (nat. size). 4. Vascular tissue as a cone in the middle of
the fleshy base (nat. size). 5. Plan of the whole organ opened out
flat (nat. size). 6. Spores (× 28). 8. A single spore showing median
slit (× 84). (After Sellards.)
A Spitzbergen, Culm, fossil recently described by Nathorst[351] as
Codonotheca (?) pusilla is briefly referred to under the genus
Pterispermostrobus.
SCHÜTZIA. Geinitz.
This generic name was instituted by Geinitz[352] for some Permian fossils
obtained by Bergmeister Schütz and regarded by the author of the genus as
probably fertile branches of some Conifer. A more complete account was
published by Goeppert[353] in his ‘Permian Flora,’ where the name
conical base which was originally surrounded by fleshy tissue (cf.
5); I–III, VI, vascular bundles (× 2). 2, 3. Segments with spores; c,
floor of cup (nat. size). 4. Vascular tissue as a cone in the middle of
the fleshy base (nat. size). 5. Plan of the whole organ opened out
flat (nat. size). 6. Spores (× 28). 8. A single spore showing median
slit (× 84). (After Sellards.)
A Spitzbergen, Culm, fossil recently described by Nathorst[351] as
Codonotheca (?) pusilla is briefly referred to under the genus
Pterispermostrobus.
SCHÜTZIA. Geinitz.
This generic name was instituted by Geinitz[352] for some Permian fossils
obtained by Bergmeister Schütz and regarded by the author of the genus as
probably fertile branches of some Conifer. A more complete account was
published by Goeppert[353] in his ‘Permian Flora,’ where the name
Page 165
Anthodiopsis Beinertiana occurs on the Plates, printed before the
publication of Geinitz’s description, but in the text the specimens are
referred to Schützia anomala.
Schützia anomala Geinitz.
The type-species, recorded from Bohemia and Silesia, is represented by
fertile shoots consisting of a thick main axis bearing apparently two-ranked
though probably spirally disposed short lateral branches, each of which
terminates in a receptacle with numerous crowded linear-lanceolate bracts
superficially resembling a partially expanded inflorescence of a Composite.
Goeppert believed that the branches bore seeds and he refers to this species
a number of detached, longitudinally striated and bluntly terminated, seeds.
The same author describes other specimens from the same localities
associated with Schützia anomala, which he names Dictyothalamus
Schrollianus[354]: in habit these agree closely with Schützia but the
receptacles, the reticulate appearance of which suggested the generic name
Dictyothalamus, bear a large number of small bodies regarded as seeds. The
preservation of the fossils is not such as to enable us to determine their true
nature but it is probable that Schützia and Dictyothalamus are not
generically distinct. In his description of Dictyothalamus Goeppert suggests
that the two associated types may be the male and female shoots of one
plant, but he speaks of seeds in both cases. Schimper[355], who unites
Dictyothalamus with Schützia, regards the latter as female and the former as
male.
Schützia Bennieana Kidston.
This species, described by Kidston[356] from the Calciferous series of
Scotland, differs from S. anomala in its much more slender axis and in the
relatively narrower and less globular clusters of bract-like appendages. The
principal axis bears three lateral branches with terminal clusters of acute
and narrow linear scale-leaves. No seeds were found in association with the
specimens.
Schützia permiensis (Renault).
Renault founded this Permian species as Antholithus permiensis[357] on a
specimen from Lodève; it consists of an incomplete inflorescence 6·4 cm.
publication of Geinitz’s description, but in the text the specimens are
referred to Schützia anomala.
Schützia anomala Geinitz.
The type-species, recorded from Bohemia and Silesia, is represented by
fertile shoots consisting of a thick main axis bearing apparently two-ranked
though probably spirally disposed short lateral branches, each of which
terminates in a receptacle with numerous crowded linear-lanceolate bracts
superficially resembling a partially expanded inflorescence of a Composite.
Goeppert believed that the branches bore seeds and he refers to this species
a number of detached, longitudinally striated and bluntly terminated, seeds.
The same author describes other specimens from the same localities
associated with Schützia anomala, which he names Dictyothalamus
Schrollianus[354]: in habit these agree closely with Schützia but the
receptacles, the reticulate appearance of which suggested the generic name
Dictyothalamus, bear a large number of small bodies regarded as seeds. The
preservation of the fossils is not such as to enable us to determine their true
nature but it is probable that Schützia and Dictyothalamus are not
generically distinct. In his description of Dictyothalamus Goeppert suggests
that the two associated types may be the male and female shoots of one
plant, but he speaks of seeds in both cases. Schimper[355], who unites
Dictyothalamus with Schützia, regards the latter as female and the former as
male.
Schützia Bennieana Kidston.
This species, described by Kidston[356] from the Calciferous series of
Scotland, differs from S. anomala in its much more slender axis and in the
relatively narrower and less globular clusters of bract-like appendages. The
principal axis bears three lateral branches with terminal clusters of acute
and narrow linear scale-leaves. No seeds were found in association with the
specimens.
Schützia permiensis (Renault).
Renault founded this Permian species as Antholithus permiensis[357] on a
specimen from Lodève; it consists of an incomplete inflorescence 6·4 cm.
Page 166
long bearing four lateral branches with stalks 1·5 to 2 cm. long terminated
by clusters of small oval bracts 5 mm. long. Renault compares the fossil
with the recent Conifers Glyptostrobus and Tsuga, but it exhibits a much
closer resemblance to Schützia anomala.
The genus Schützia, originally described from Permian strata, is recorded
also from Westphalian strata in North Africa[358] as well as from Lower
Carboniferous rocks in Scotland. The data at present available are
insufficient to determine the morphological nature of the fertile branches:
the evidence adduced by Goeppert in support of the occurrence of seeds is
not convincing and the interpretation of the bract-like appendages is still an
open question; they may have formed a cupular investment to seeds, but in
the Scotch species the general appearance rather suggests that they may be
microspore-bearing organs comparable with those of Codonotheca[359].
There are no adequate grounds for supposing Schützia to belong to the
Coniferales, a view advanced by some authors; it is much more likely to
represent the fertile shoots of a Pteridosperm.
WHITTLESEYA. Newberry.
The genus Whittleseya, referred by many authors to the Ginkgoales, has
no substantial claim to be regarded as allied to that group: its position is still
uncertain, but the recent discovery of fertile specimens suggests the
probability of a relationship to Potoniea and an identification of
Whittleseya as another form of microsporophyll of a Pteridosperm.
by clusters of small oval bracts 5 mm. long. Renault compares the fossil
with the recent Conifers Glyptostrobus and Tsuga, but it exhibits a much
closer resemblance to Schützia anomala.
The genus Schützia, originally described from Permian strata, is recorded
also from Westphalian strata in North Africa[358] as well as from Lower
Carboniferous rocks in Scotland. The data at present available are
insufficient to determine the morphological nature of the fertile branches:
the evidence adduced by Goeppert in support of the occurrence of seeds is
not convincing and the interpretation of the bract-like appendages is still an
open question; they may have formed a cupular investment to seeds, but in
the Scotch species the general appearance rather suggests that they may be
microspore-bearing organs comparable with those of Codonotheca[359].
There are no adequate grounds for supposing Schützia to belong to the
Coniferales, a view advanced by some authors; it is much more likely to
represent the fertile shoots of a Pteridosperm.
WHITTLESEYA. Newberry.
The genus Whittleseya, referred by many authors to the Ginkgoales, has
no substantial claim to be regarded as allied to that group: its position is still
uncertain, but the recent discovery of fertile specimens suggests the
probability of a relationship to Potoniea and an identification of
Whittleseya as another form of microsporophyll of a Pteridosperm.
Page 167
Fig. 428.
A, C. Whittleseya elegans. A, single leaflet, from Pennsylvania. (After
Lesquereux; ⅚ nat. size.) C, diagrammatic sketch of part of a
leaflet showing the teeth, the striated texture of the carbonised
layer, and the vein-like markings on a lower surface. (After
Thomas; enlarged.)
B. Whittleseya brevifolia. (After White; the smaller figure ⅚ nat. size.)
The generic name was given by Newberry[360] to some leaves, or possibly
leaflets, originally described by C. Whittlesey from the Coal Measures of
Ohio. Whittleseya is represented by species from several North American
localities[361] in Ohio, Pennsylvania, Arkansas, Nova Scotia, and New
Brunswick[362]; it occurs in Silesia and has recently been found in the
English Coal Measures[363]. The genus is confined to Upper Carboniferous
strata.
The leaves are fairly thick; the lamina is oblong, cuneate, broadly
triangular or linear, usually rounded and truncate (fig. 428, A, C), generally
dentate at the distal end, the proximal portion being gradually or abruptly
contracted and occasionally prolonged into a short pedicel. The veins or ribs
are parallel to the sides of the lamina and except near the base unbranched.
A, C. Whittleseya elegans. A, single leaflet, from Pennsylvania. (After
Lesquereux; ⅚ nat. size.) C, diagrammatic sketch of part of a
leaflet showing the teeth, the striated texture of the carbonised
layer, and the vein-like markings on a lower surface. (After
Thomas; enlarged.)
B. Whittleseya brevifolia. (After White; the smaller figure ⅚ nat. size.)
The generic name was given by Newberry[360] to some leaves, or possibly
leaflets, originally described by C. Whittlesey from the Coal Measures of
Ohio. Whittleseya is represented by species from several North American
localities[361] in Ohio, Pennsylvania, Arkansas, Nova Scotia, and New
Brunswick[362]; it occurs in Silesia and has recently been found in the
English Coal Measures[363]. The genus is confined to Upper Carboniferous
strata.
The leaves are fairly thick; the lamina is oblong, cuneate, broadly
triangular or linear, usually rounded and truncate (fig. 428, A, C), generally
dentate at the distal end, the proximal portion being gradually or abruptly
contracted and occasionally prolonged into a short pedicel. The veins or ribs
are parallel to the sides of the lamina and except near the base unbranched.
Page 168
Whittleseya elegans Newberry.
The type-species, from North America and Europe, is characterised by its
shovel-like lamina from 3 to 6 cm. long closely resembling in shape some
lepidopterous scales; the surface is ribbed, each rib corresponding to a tooth
on the distal margin; on each of the parallel ridges are 4–5 longitudinal lines
indicating either veins or stereome strands (fig. 428, A, C). The examination
of preparations made by Dr Kidston from a leaflet of this species enables
me to add a few facts with regard to the microspores. The spores, which
cover almost the whole surface of the lamina, show a tendency to a more or
less definite arrangement in longitudinal rows. Two types of cuticularised
membrane are represented among the associated fragments: in some pieces
of cuticle the cells are short and have straight walls while in others the
preservation is inferior and the cells appear to be longer and narrower. One
or both of these membranes probably belong to the sporangia. The oval slit,
which is a striking feature on several of the spores (fig. 429), points to their
bilateral nature and dehiscence along the major axis. A comparison of these
spores with those obtained by Kidston from the English species Whittleseya
fertilis reveals a very close agreement both in size and shape and confirms
the identification of the Staffordshire specimens as leaflets of Whittleseya.
The large size of the microspores and the gaping oval aperture in some of
them are features in which they agree closely with the spores of
Dolerophyllum fertile described by Renault[364]. In both cases the spores
tend to be arranged in long groups and they are practically identical in form
and in the nature of the exine; those of Dolerophyllum are 280μ long while
those of W. fertilis reach a length of 220μ. In some of the Whittleseya spores
the exine has split as in the specimen shown in fig. 429, but in others there
are two curved lines along which dehiscence has begun, a character in
which the spores appear to be identical with those of Dolerophyllum
described by Renault who speaks of dehiscence by means of an operculum.
There is, I venture to think, little doubt as to the very close affinity of the
two types. The systematic position of Dolerophyllum is not certainly
established; if the generic identity of the leaves described as D. Berthieri
Ren. and the petrified specimens named D. fertile is assumed, it is a
legitimate inference that the genus is founded on fertile pinnules of a
Pteridosperm with foliage of the Neuropteris or Cyclopteris form. It would
seem probable that both Whittleseya and Dolerophyllum fertile are
The type-species, from North America and Europe, is characterised by its
shovel-like lamina from 3 to 6 cm. long closely resembling in shape some
lepidopterous scales; the surface is ribbed, each rib corresponding to a tooth
on the distal margin; on each of the parallel ridges are 4–5 longitudinal lines
indicating either veins or stereome strands (fig. 428, A, C). The examination
of preparations made by Dr Kidston from a leaflet of this species enables
me to add a few facts with regard to the microspores. The spores, which
cover almost the whole surface of the lamina, show a tendency to a more or
less definite arrangement in longitudinal rows. Two types of cuticularised
membrane are represented among the associated fragments: in some pieces
of cuticle the cells are short and have straight walls while in others the
preservation is inferior and the cells appear to be longer and narrower. One
or both of these membranes probably belong to the sporangia. The oval slit,
which is a striking feature on several of the spores (fig. 429), points to their
bilateral nature and dehiscence along the major axis. A comparison of these
spores with those obtained by Kidston from the English species Whittleseya
fertilis reveals a very close agreement both in size and shape and confirms
the identification of the Staffordshire specimens as leaflets of Whittleseya.
The large size of the microspores and the gaping oval aperture in some of
them are features in which they agree closely with the spores of
Dolerophyllum fertile described by Renault[364]. In both cases the spores
tend to be arranged in long groups and they are practically identical in form
and in the nature of the exine; those of Dolerophyllum are 280μ long while
those of W. fertilis reach a length of 220μ. In some of the Whittleseya spores
the exine has split as in the specimen shown in fig. 429, but in others there
are two curved lines along which dehiscence has begun, a character in
which the spores appear to be identical with those of Dolerophyllum
described by Renault who speaks of dehiscence by means of an operculum.
There is, I venture to think, little doubt as to the very close affinity of the
two types. The systematic position of Dolerophyllum is not certainly
established; if the generic identity of the leaves described as D. Berthieri
Ren. and the petrified specimens named D. fertile is assumed, it is a
legitimate inference that the genus is founded on fertile pinnules of a
Pteridosperm with foliage of the Neuropteris or Cyclopteris form. It would
seem probable that both Whittleseya and Dolerophyllum fertile are
Page 169
microspore-bearing leaflets of Pteridosperms, possibly of some Medullosan
plants. The leaflets of Whittleseya agree in form fairly closely with those of
Potoniea adiantiformis Zeill. described on a previous page[365] as the male
organs of a Pteridosperm.
Fig. 429. Microspores of Whittleseya elegans. A, a group of spores; B, a
single spore. (Preparations made from an American specimen, No.
2314, in Dr Kidston’s Collection.)
The specimens described by Lesquereux from Pennsylvania as W.
integrifolia and W. undulata are less satisfactory than W. elegans. The
Arkansas species W. microphylla[366], characterised by the obcuneate form of
the lamina, is said to occur not only as detached leaflets but in loose
bunches at the ends of slender axes, a circumstance favourable to the
suggestion, based on the recently described English specimens, that the
Whittleseya leaves may be fertile pinnules of a Pteridosperm frond. Among
other species attributed to Newberry’s genus is W. brevifolia Wh. from
Nova Scotia[367] with much smaller broadly triangular leaves 7 mm. long
exclusive of the petiole and 8 mm. broad at the distal end (fig. 428, B). Dr
plants. The leaflets of Whittleseya agree in form fairly closely with those of
Potoniea adiantiformis Zeill. described on a previous page[365] as the male
organs of a Pteridosperm.
Fig. 429. Microspores of Whittleseya elegans. A, a group of spores; B, a
single spore. (Preparations made from an American specimen, No.
2314, in Dr Kidston’s Collection.)
The specimens described by Lesquereux from Pennsylvania as W.
integrifolia and W. undulata are less satisfactory than W. elegans. The
Arkansas species W. microphylla[366], characterised by the obcuneate form of
the lamina, is said to occur not only as detached leaflets but in loose
bunches at the ends of slender axes, a circumstance favourable to the
suggestion, based on the recently described English specimens, that the
Whittleseya leaves may be fertile pinnules of a Pteridosperm frond. Among
other species attributed to Newberry’s genus is W. brevifolia Wh. from
Nova Scotia[367] with much smaller broadly triangular leaves 7 mm. long
exclusive of the petiole and 8 mm. broad at the distal end (fig. 428, B). Dr
Page 170
Matthew[368] has also described a Canadian species W. concinna from New
Brunswick in beds assigned by Dr Stopes[369] to the Westphalian series.
Whittleseya fertilis Kidston.
Since the discovery of Whittleseya elegans in the Coal Measures of
Staffordshire recorded by Mr Thomas, Dr Kidston has published an account
of some specimens from the same district under the name Whittleseya (?)
fertilis[370]: these consist of smaller cuneate scale-leaves or leaflets 1·4–2·4
cm. long and 8–9 mm. broad; the lamina has a dentate upper margin and is
longitudinally ribbed. The scales occur in superposed pairs, closely fitting
but not organically connected, at least in the state in which they are
preserved; each pair forms a sporangium-like case enclosing numerous
spores but the actual sporangia or synangia have not been preserved.
Kidston describes the spores as 210–222μ in length, elliptical, and
characterised in many cases by an oval slit; they are practically identical
with the microspores of W. elegans.
DOLEROPHYLLUM. Saporta.
This name was proposed[371] primarily for a large ovoid petrified bud
composed of rolled Cyclopteroid leaves from Permian rocks in the Ural
Mountains, which had been previously described by more than one writer
under different names and regarded as a young shoot of a Palm or other
Monocotyledon. Eichwald[372], who published good drawings, called the
fossil Noeggerathia Goepperti. Saporta connected with this species some
leaf-impressions from the Permian of Bohemia described by Goeppert[373] as
Noeggerathia cyclopteroides: in his family Dolerophylleae[374] the French
author included other leaves which are probably not closely related to the
type-species, Dolerophyllum Goepperti. The Dolerophylleae are spoken of
by Saporta and Marion[375] as Progymnosperms. Before the publication of
Saporta’s note Grand’Eury had instituted the genus Doleropteris[376] and the
family Doleropteroideae; in the former he included several forms of leaves
agreeing generally with Goeppert’s Noeggerathia cyclopteroides. Zeiller[377]
adopts Grand’Eury’s designation for the Russian fossil in preference to
Dolerophyllum, a choice justified by considerations of priority; but the
latter name is retained in this account as it was assigned by Saporta to the
Brunswick in beds assigned by Dr Stopes[369] to the Westphalian series.
Whittleseya fertilis Kidston.
Since the discovery of Whittleseya elegans in the Coal Measures of
Staffordshire recorded by Mr Thomas, Dr Kidston has published an account
of some specimens from the same district under the name Whittleseya (?)
fertilis[370]: these consist of smaller cuneate scale-leaves or leaflets 1·4–2·4
cm. long and 8–9 mm. broad; the lamina has a dentate upper margin and is
longitudinally ribbed. The scales occur in superposed pairs, closely fitting
but not organically connected, at least in the state in which they are
preserved; each pair forms a sporangium-like case enclosing numerous
spores but the actual sporangia or synangia have not been preserved.
Kidston describes the spores as 210–222μ in length, elliptical, and
characterised in many cases by an oval slit; they are practically identical
with the microspores of W. elegans.
DOLEROPHYLLUM. Saporta.
This name was proposed[371] primarily for a large ovoid petrified bud
composed of rolled Cyclopteroid leaves from Permian rocks in the Ural
Mountains, which had been previously described by more than one writer
under different names and regarded as a young shoot of a Palm or other
Monocotyledon. Eichwald[372], who published good drawings, called the
fossil Noeggerathia Goepperti. Saporta connected with this species some
leaf-impressions from the Permian of Bohemia described by Goeppert[373] as
Noeggerathia cyclopteroides: in his family Dolerophylleae[374] the French
author included other leaves which are probably not closely related to the
type-species, Dolerophyllum Goepperti. The Dolerophylleae are spoken of
by Saporta and Marion[375] as Progymnosperms. Before the publication of
Saporta’s note Grand’Eury had instituted the genus Doleropteris[376] and the
family Doleropteroideae; in the former he included several forms of leaves
agreeing generally with Goeppert’s Noeggerathia cyclopteroides. Zeiller[377]
adopts Grand’Eury’s designation for the Russian fossil in preference to
Dolerophyllum, a choice justified by considerations of priority; but the
latter name is retained in this account as it was assigned by Saporta to the
Page 171
specimen of greatest botanical interest, namely Dolerophyllum Goepperti,
and because it does not suggest affinity to Ferns.
Dolerophyllum Goepperti (Eichwald).
The type-species is from the Zechstein of Orenburg in the Urals and no
specimens having precisely the same structure have been found elsewhere.
Eichwald assigned it, with leaf-impressions of various kinds, to the
Noeggerathieae and named it Noeggerathia Goepperti: it had previously
been described by Kutorga[378] as Aroides crassispatha and Unger[379]
included it among the Palms as Palaeospathe aroidea. The species has been
described also by Saporta and Marion and by Renault[380]. The following
account is based on sections cut from a specimen in the British Museum[381]
which, though assigned on the label (within a query) to France and named
Dolerophyllum Berthieri, is undoubtedly Eichwald’s species from East
Russia.
Fig. 430. Dolerophyllum Goepperti. Bud in surface-view, A; in
longitudinal section, B, C; in transverse section, D. (British
Museum; A, ⅔ nat. size.)
The specimen (fig. 430) is 9 cm. long and 4·2 cm. broad: at the slightly
contracted and broken base is a piece of immature axis (fig. 430, B, a) 12
and because it does not suggest affinity to Ferns.
Dolerophyllum Goepperti (Eichwald).
The type-species is from the Zechstein of Orenburg in the Urals and no
specimens having precisely the same structure have been found elsewhere.
Eichwald assigned it, with leaf-impressions of various kinds, to the
Noeggerathieae and named it Noeggerathia Goepperti: it had previously
been described by Kutorga[378] as Aroides crassispatha and Unger[379]
included it among the Palms as Palaeospathe aroidea. The species has been
described also by Saporta and Marion and by Renault[380]. The following
account is based on sections cut from a specimen in the British Museum[381]
which, though assigned on the label (within a query) to France and named
Dolerophyllum Berthieri, is undoubtedly Eichwald’s species from East
Russia.
Fig. 430. Dolerophyllum Goepperti. Bud in surface-view, A; in
longitudinal section, B, C; in transverse section, D. (British
Museum; A, ⅔ nat. size.)
The specimen (fig. 430) is 9 cm. long and 4·2 cm. broad: at the slightly
contracted and broken base is a piece of immature axis (fig. 430, B, a) 12
Page 172
mm. in diameter overtopped by a mass of closely packed leaves encircling
one another like the bulb-scales of an Onion (fig. 430 A, C)[382]. Most of the
leaves included in the bud were attached to the axis below the broken base.
The curved, dichotomously branched, veins are seen on some of the pieces
of lamina on the surface of the bud (fig. 430, A). The considerable breadth
of the leaves is demonstrated by the longitudinal and transverse sections. In
fig. C most of the laminae can be traced through the whole height of each of
the steep-sided arches: a few overlapping margins are seen in fig. D. The
veins are for the most part imperfectly preserved and appear as clear spaces
at regular intervals in the brown mesophyll. The axis of the shoot consists
of homogeneous parenchyma except near the sloping sides where narrow
dark bands (fig. 430, B, a) mark the position of desmogen-strands of thin-
walled elongated elements representing an early stage in the development
of vascular bundles some of which have already produced spiral tracheids.
Short secretory cells accompany the immature conducting elements. The
lamina slightly exceeds 2 mm. in thickness in the broadest part: the
mesophyll is composed of large parenchymatous cells of elliptical or
spherical form often loosely attached owing to the well-developed system
of intercellular spaces. The lower epidermis, assuming that the outer face of
the rolled leaves is the morphologically lower surface, forms a uniform
layer of palisade cells characterised by their free conical ends (fig. 431, A,
B, e) which in some oblique sections appear as sharply pointed papillae
with almost filiform apices; but while the cells were doubtless papillose like
those of the epidermis of a velvety petal, the pointed form is due in part to
the greater distinctness of the dark contents as compared with the lighter
cell-walls. The upper epidermis is much less distinct; it consists of smaller
flattened cells with occasional stomata. Renault[383] figures a specimen with
stomata in a better state of preservation. The vascular bundles are rendered
conspicuous by large secretory cells on the lower side, in the larger veins in
the form of an arc or irregular group (fig. 432, A), but in the finer veins as
single cells (fig. 431, A, B). These sacs resemble the tannin cells
accompanying the veins in a leaf of Ginkgo (cf. fig. 631, G). The xylem-
elements are of two kinds, (i) elongated spiral and scalariform conducting
elements, forming a vertical plate of a few rows in the larger veins (figs.
431, 432) or a small compact group in the more slender veins (fig. 413, A,
B); (ii) much larger isodiametric cells with reticulate or spiral thickening
resembling the transfusion-tracheids of Conifers or, perhaps more closely,
one another like the bulb-scales of an Onion (fig. 430 A, C)[382]. Most of the
leaves included in the bud were attached to the axis below the broken base.
The curved, dichotomously branched, veins are seen on some of the pieces
of lamina on the surface of the bud (fig. 430, A). The considerable breadth
of the leaves is demonstrated by the longitudinal and transverse sections. In
fig. C most of the laminae can be traced through the whole height of each of
the steep-sided arches: a few overlapping margins are seen in fig. D. The
veins are for the most part imperfectly preserved and appear as clear spaces
at regular intervals in the brown mesophyll. The axis of the shoot consists
of homogeneous parenchyma except near the sloping sides where narrow
dark bands (fig. 430, B, a) mark the position of desmogen-strands of thin-
walled elongated elements representing an early stage in the development
of vascular bundles some of which have already produced spiral tracheids.
Short secretory cells accompany the immature conducting elements. The
lamina slightly exceeds 2 mm. in thickness in the broadest part: the
mesophyll is composed of large parenchymatous cells of elliptical or
spherical form often loosely attached owing to the well-developed system
of intercellular spaces. The lower epidermis, assuming that the outer face of
the rolled leaves is the morphologically lower surface, forms a uniform
layer of palisade cells characterised by their free conical ends (fig. 431, A,
B, e) which in some oblique sections appear as sharply pointed papillae
with almost filiform apices; but while the cells were doubtless papillose like
those of the epidermis of a velvety petal, the pointed form is due in part to
the greater distinctness of the dark contents as compared with the lighter
cell-walls. The upper epidermis is much less distinct; it consists of smaller
flattened cells with occasional stomata. Renault[383] figures a specimen with
stomata in a better state of preservation. The vascular bundles are rendered
conspicuous by large secretory cells on the lower side, in the larger veins in
the form of an arc or irregular group (fig. 432, A), but in the finer veins as
single cells (fig. 431, A, B). These sacs resemble the tannin cells
accompanying the veins in a leaf of Ginkgo (cf. fig. 631, G). The xylem-
elements are of two kinds, (i) elongated spiral and scalariform conducting
elements, forming a vertical plate of a few rows in the larger veins (figs.
431, 432) or a small compact group in the more slender veins (fig. 413, A,
B); (ii) much larger isodiametric cells with reticulate or spiral thickening
resembling the transfusion-tracheids of Conifers or, perhaps more closely,
Page 173
similar elements in the leaves of Lepidodendron. These short tracheids are
especially abundant on the flanks of the conducting tracheids (figs. 431, t;
432, A, t), but they sometimes form a complete investment. In the obliquely
cut vein reproduced in fig. 431, D, the transfusion-tracheids are abundant: a
few are enlarged in fig. 431, E. In the smaller veins (fig. 431, A, B) they are
represented by the larger elements, t, on the sides of the conducting strands.
The protoxylem lies close to the upper edge in the middle line (px, figs.
431, A; 432, A); it is difficult to determine its precise position, but it would
seem to be slightly internal, the bundle being not quite endarch. No phloem
was recognised in the British Museum specimen, but it presumably
occurred, if present, where the black patch is shown in fig. 432, A. Renault
describes some phloem in sections which he examined.
especially abundant on the flanks of the conducting tracheids (figs. 431, t;
432, A, t), but they sometimes form a complete investment. In the obliquely
cut vein reproduced in fig. 431, D, the transfusion-tracheids are abundant: a
few are enlarged in fig. 431, E. In the smaller veins (fig. 431, A, B) they are
represented by the larger elements, t, on the sides of the conducting strands.
The protoxylem lies close to the upper edge in the middle line (px, figs.
431, A; 432, A); it is difficult to determine its precise position, but it would
seem to be slightly internal, the bundle being not quite endarch. No phloem
was recognised in the British Museum specimen, but it presumably
occurred, if present, where the black patch is shown in fig. 432, A. Renault
describes some phloem in sections which he examined.
Page 174
Fig. 431. Dolerophyllum Goepperti. Transverse sections of leaves. e,
epidermis; s, secretory cells; t, transfusion-tracheids; px,
protoxylem. (British Museum.)
The mesophyll next the upper surface is in most cases represented by
spaces between the veins which give a crenulated outline to the parenchyma
(fig. 430, C, D); in some places the spaces contain remains of very loose
and crowded cells suggesting the original presence of very lacunar tissue or
possibly of thin-walled storage-cells. The confinement of stomata to what is
assumed to be the upper surface may, as Renault and others have suggested,
epidermis; s, secretory cells; t, transfusion-tracheids; px,
protoxylem. (British Museum.)
The mesophyll next the upper surface is in most cases represented by
spaces between the veins which give a crenulated outline to the parenchyma
(fig. 430, C, D); in some places the spaces contain remains of very loose
and crowded cells suggesting the original presence of very lacunar tissue or
possibly of thin-walled storage-cells. The confinement of stomata to what is
assumed to be the upper surface may, as Renault and others have suggested,
Page 175
indicate leaves which floated on water, an inference opposed to the view
that the gaps in the mesophyll mark the position of water-tissue.
No specimens have been described which enable us to correlate with
certainty mature leaves or foliage-shoots with the petrified bud. It is,
however, not improbable that the impression from Mount Pelé near Epinac
named by Renault Dolerophyllum Berthieri[384] may be correctly referred to
the same genus. The type-specimen consists of an axis, whether a rachis of
a compound leaf or a shoot with simple leaves cannot be determined,
bearing partially overlapping more or less orbicular leaves 18–20 cm. in
diameter, with a Cyclopteris venation. Among other leaves of unknown
affinity referred to the same genus attention is drawn to Dolerophyllum
pseudopeltatum (Grand’Eury)[385] with an orbicular lamina reaching in some
specimens 22 × 19 cm. Specimens of Dolerophyllum pseudopeltatum are
figured by Renault from the Commentry coal-field[386], some of which reach
a diameter of 12 cm. The only British specimen of a leaflet of this type
which I have seen is one in Dr Kidston’s collection from the Stephanian
series, Glamorganshire. It is probable that some at least of the impressions
assigned to Dolerophyllum or Doleropteris would be more appropriately
included in Cyclopteris or Cardiopteris and may have been borne on the
axis of large Pteridosperm fronds. Grand’Eury[387] has also called attention
to the difficulty of distinguishing the larger Cyclopteris leaflets from
Dolerophyllum. Some of the Cyclopteroid leaflets figured by Roehl[388] on
Neuropteris fronds differ but slightly from those of D. pseudopeltatum. The
shoot showing large leaf-scars figured by Saporta and Marion[389] as
probably the axis of a Dolerophyllum may well be a piece of Cordaites.
that the gaps in the mesophyll mark the position of water-tissue.
No specimens have been described which enable us to correlate with
certainty mature leaves or foliage-shoots with the petrified bud. It is,
however, not improbable that the impression from Mount Pelé near Epinac
named by Renault Dolerophyllum Berthieri[384] may be correctly referred to
the same genus. The type-specimen consists of an axis, whether a rachis of
a compound leaf or a shoot with simple leaves cannot be determined,
bearing partially overlapping more or less orbicular leaves 18–20 cm. in
diameter, with a Cyclopteris venation. Among other leaves of unknown
affinity referred to the same genus attention is drawn to Dolerophyllum
pseudopeltatum (Grand’Eury)[385] with an orbicular lamina reaching in some
specimens 22 × 19 cm. Specimens of Dolerophyllum pseudopeltatum are
figured by Renault from the Commentry coal-field[386], some of which reach
a diameter of 12 cm. The only British specimen of a leaflet of this type
which I have seen is one in Dr Kidston’s collection from the Stephanian
series, Glamorganshire. It is probable that some at least of the impressions
assigned to Dolerophyllum or Doleropteris would be more appropriately
included in Cyclopteris or Cardiopteris and may have been borne on the
axis of large Pteridosperm fronds. Grand’Eury[387] has also called attention
to the difficulty of distinguishing the larger Cyclopteris leaflets from
Dolerophyllum. Some of the Cyclopteroid leaflets figured by Roehl[388] on
Neuropteris fronds differ but slightly from those of D. pseudopeltatum. The
shoot showing large leaf-scars figured by Saporta and Marion[389] as
probably the axis of a Dolerophyllum may well be a piece of Cordaites.
Page 176
Fig. 432. A. Dolerophyllum Goepperti, section of vein. B. Dolerophyllum
Berthieri; s, microspores. C. Dolerophyllum fertile. D.
Dolerophyllum fertile, microspores. (After Renault.)
Microsporophylls assigned to Dolerophyllum.
Certain problematical fossils found in association with the sterile leaves
of Dolerophyllum Berthieri have been described by Renault as the male
organs of that species. These are elliptical discs, 6 × 5 cm., with an
excentrically placed stalk: embedded in a carbonised lamina are numerous
rows of elliptical bodies, 410μ × 280μ, characterised by two curved
Berthieri; s, microspores. C. Dolerophyllum fertile. D.
Dolerophyllum fertile, microspores. (After Renault.)
Microsporophylls assigned to Dolerophyllum.
Certain problematical fossils found in association with the sterile leaves
of Dolerophyllum Berthieri have been described by Renault as the male
organs of that species. These are elliptical discs, 6 × 5 cm., with an
excentrically placed stalk: embedded in a carbonised lamina are numerous
rows of elliptical bodies, 410μ × 280μ, characterised by two curved
Page 177
longitudinal grooves on the surface and regarded by Renault as pollen-
grains. The chains of these microspores radiate outwards from the
neighbourhood of the stalk and cover most of the surface of the disc (fig.
432, B). Some silicified pieces of similar spore-bearing discs from Grand’
Croix named Dolerophyllum fertile[390] afford additional information as to
these remarkable reproductive organs. The earlier account of this species by
Renault is confirmed by Solms-Laubach[391] who examined the original
sections. The peltate fleshy discs preserved as incomplete specimens consist
of lacunar parenchyma 15–18 mm. thick traversed at right angles to the
surface by numerous loculi (fig. 432, C), circular or oval in transverse
section, containing large numbers of microspores, s, similar in size and
form to those on the carbonised discs of the Mt Pelé specimen. Vascular
strands occur between and parallel to the spore-chambers. The spores
contain 8–10 cells (fig. 432, D) and Renault believes that dehiscence of the
exine occurred along the two deep grooves which mark the limits of an
operculum. He emphasises the peculiar structure of the microspores by
speaking of them as prepollinia: in size and in the presence of internal cells
(? male prothallus) they resemble the spores found in the pollen-chamber of
a seed described by Renault as Aetheotesta elliptica[392] which he thinks may
belong to a member of the Dolerophylleae. It has also been suggested that
Codonospermum may be a seed of Dolerophyllum[393]. An unconvincing
specimen described by Saporta and Marion[394] as a seed-bearing bract is
regarded by them as referable to Dolerophyllum, but the evidence for any
connexion is far from satisfactory.
There is nothing definite to be said with regard to the affinity of
Dolerophyllum Goepperti or the microsporophylls represented by D. fertile
and the specimens associated with D. Berthieri. Renault considers that both
sterile and fertile specimens belong to the same genus, which he assigns to
a position between Pteridophytes and Cycads. As Solms-Laubach says, the
evidence supplied by the structure of the veins of D. Goepperti in favour of
a cycadean alliance is not convincing. The type of vernation is unlike that of
any known Cycad or indeed of any Gymnosperm: the large size of the
leaves is another though weaker objection to this comparison, as the pinnae
of Bowenia (fig. 391) and especially those of some species of Zamia (fig.
388), are of equal or larger dimensions. If, as seems probable, the xylem-
strands are mesarch that is a point of contact with recent Cycads, but the
bundle as a whole bears but a remote resemblance to that of a cycadean leaf
grains. The chains of these microspores radiate outwards from the
neighbourhood of the stalk and cover most of the surface of the disc (fig.
432, B). Some silicified pieces of similar spore-bearing discs from Grand’
Croix named Dolerophyllum fertile[390] afford additional information as to
these remarkable reproductive organs. The earlier account of this species by
Renault is confirmed by Solms-Laubach[391] who examined the original
sections. The peltate fleshy discs preserved as incomplete specimens consist
of lacunar parenchyma 15–18 mm. thick traversed at right angles to the
surface by numerous loculi (fig. 432, C), circular or oval in transverse
section, containing large numbers of microspores, s, similar in size and
form to those on the carbonised discs of the Mt Pelé specimen. Vascular
strands occur between and parallel to the spore-chambers. The spores
contain 8–10 cells (fig. 432, D) and Renault believes that dehiscence of the
exine occurred along the two deep grooves which mark the limits of an
operculum. He emphasises the peculiar structure of the microspores by
speaking of them as prepollinia: in size and in the presence of internal cells
(? male prothallus) they resemble the spores found in the pollen-chamber of
a seed described by Renault as Aetheotesta elliptica[392] which he thinks may
belong to a member of the Dolerophylleae. It has also been suggested that
Codonospermum may be a seed of Dolerophyllum[393]. An unconvincing
specimen described by Saporta and Marion[394] as a seed-bearing bract is
regarded by them as referable to Dolerophyllum, but the evidence for any
connexion is far from satisfactory.
There is nothing definite to be said with regard to the affinity of
Dolerophyllum Goepperti or the microsporophylls represented by D. fertile
and the specimens associated with D. Berthieri. Renault considers that both
sterile and fertile specimens belong to the same genus, which he assigns to
a position between Pteridophytes and Cycads. As Solms-Laubach says, the
evidence supplied by the structure of the veins of D. Goepperti in favour of
a cycadean alliance is not convincing. The type of vernation is unlike that of
any known Cycad or indeed of any Gymnosperm: the large size of the
leaves is another though weaker objection to this comparison, as the pinnae
of Bowenia (fig. 391) and especially those of some species of Zamia (fig.
388), are of equal or larger dimensions. If, as seems probable, the xylem-
strands are mesarch that is a point of contact with recent Cycads, but the
bundle as a whole bears but a remote resemblance to that of a cycadean leaf
Page 178
and is much more like the veins of Ginkgo. The bud shown in fig. 430, A, is
probably a young shoot and not merely a large compound leaf. If it were an
unexpanded frond of Neuropteris bearing Cyclopteris pinnules we should
expect to find indications of scattered desmogen-strands such as would
occur in the Myeloxylon type of rachis. The resemblance to most forms of
Cordaites is by no means close though a few leaves referred to that genus
(e.g. C. circularis, fig. 468, B) are similar to those of Dolerophyllum[395].
The male organs are unlike those of any other plant: they may be
described as sporophylls with microsporangia or perhaps synangia
embedded in the mesophyll and containing microspores similar to those of
some Pteridosperms or true Gymnosperms. Attention has been called to the
close resemblance of the spores shown in fig. 432, C, D to those recently
discovered by Kidston and referred to the genus Whittleseya (fig. 429), and
it is very probable that the striking similarity is an index of affinity.
Ottokaria. Zeiller.
Ottokaria bengalensis Zeiller. A specimen of doubtful affinity from the
Lower Gondwana (Karharbari beds) of Passerabhia, India, was originally
described by Zeiller[396] as Feistmantelia bengalensis, but in a postscript he
substituted the name Ottokaria on the ground that Feistmantelia had
previously been employed by Lester Ward. Fig. 433 is drawn from the
original specimen: it consists of a stalk attached in a slightly excentric
position to an almost orbicular lamina, 2·5 cm. in diameter, with subacute
marginal teeth and traversed by numerous radially disposed striations.
Zeiller compares the fossil with Whittleseya elegans and Rhipidopsis
ginkgoides and assigns it with some hesitation to the Salisburieae. An
examination of the type-specimen led me to form the opinion that it may be
a cupular organ of a Pteridosperm that enclosed a seed. The lamina is
slightly concave and has the form of a shallow cup; moreover the surface-
features resemble those of a bract rather than the regularly veined lamina of
a foliage-leaf. The specimen bears a very close resemblance to one figured
by Bertrand[397] as the cupule of Hexapterospermum modestae which he
connects with fronds of Neuropteris gigantea.
probably a young shoot and not merely a large compound leaf. If it were an
unexpanded frond of Neuropteris bearing Cyclopteris pinnules we should
expect to find indications of scattered desmogen-strands such as would
occur in the Myeloxylon type of rachis. The resemblance to most forms of
Cordaites is by no means close though a few leaves referred to that genus
(e.g. C. circularis, fig. 468, B) are similar to those of Dolerophyllum[395].
The male organs are unlike those of any other plant: they may be
described as sporophylls with microsporangia or perhaps synangia
embedded in the mesophyll and containing microspores similar to those of
some Pteridosperms or true Gymnosperms. Attention has been called to the
close resemblance of the spores shown in fig. 432, C, D to those recently
discovered by Kidston and referred to the genus Whittleseya (fig. 429), and
it is very probable that the striking similarity is an index of affinity.
Ottokaria. Zeiller.
Ottokaria bengalensis Zeiller. A specimen of doubtful affinity from the
Lower Gondwana (Karharbari beds) of Passerabhia, India, was originally
described by Zeiller[396] as Feistmantelia bengalensis, but in a postscript he
substituted the name Ottokaria on the ground that Feistmantelia had
previously been employed by Lester Ward. Fig. 433 is drawn from the
original specimen: it consists of a stalk attached in a slightly excentric
position to an almost orbicular lamina, 2·5 cm. in diameter, with subacute
marginal teeth and traversed by numerous radially disposed striations.
Zeiller compares the fossil with Whittleseya elegans and Rhipidopsis
ginkgoides and assigns it with some hesitation to the Salisburieae. An
examination of the type-specimen led me to form the opinion that it may be
a cupular organ of a Pteridosperm that enclosed a seed. The lamina is
slightly concave and has the form of a shallow cup; moreover the surface-
features resemble those of a bract rather than the regularly veined lamina of
a foliage-leaf. The specimen bears a very close resemblance to one figured
by Bertrand[397] as the cupule of Hexapterospermum modestae which he
connects with fronds of Neuropteris gigantea.
Page 179
Fig. 433. Ottokaria bengalensis. (Nat. size; drawn from the type-
specimen.)
Ottokaria occurs in association with fronds of Glossopteris indica and
with the large seeds described by Zeiller[398] as Cardiocarpus indicus. I have
lately obtained some evidence in favour of assigning Feistmantel’s seeds
Carpolithes Milleri[399] to the genus Glossopteris: among several specimens
from the Lower Gondwana rocks of India I found an example showing a
seed partially covered by a scale-leaf in its natural position which appears
to be identical with scale-leaves of Glossopteris. It may be that the
specimen represented in fig. 433 belongs to Cardiocarpus indicus, though
this is a mere guess: my belief is that Ottokaria is a cupular organ that
specimen.)
Ottokaria occurs in association with fronds of Glossopteris indica and
with the large seeds described by Zeiller[398] as Cardiocarpus indicus. I have
lately obtained some evidence in favour of assigning Feistmantel’s seeds
Carpolithes Milleri[399] to the genus Glossopteris: among several specimens
from the Lower Gondwana rocks of India I found an example showing a
seed partially covered by a scale-leaf in its natural position which appears
to be identical with scale-leaves of Glossopteris. It may be that the
specimen represented in fig. 433 belongs to Cardiocarpus indicus, though
this is a mere guess: my belief is that Ottokaria is a cupular organ that
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enclosed the base of a seed borne on a Pteridosperm. There is little doubt
that as additional data are obtained it will be found that Pteridosperms
played no inconsiderable part in the vegetation of Gondwana Land.
Fig. 434. Strobilites Milleryensis. (Natural size; after Renault.)
Strobilites. Schimper and Mougeot.
Strobilites Milleryensis (Renault).
This species, from the Permian of France, was placed by Renault in
Cycadospadix[400], but having regard to the fact that it differs essentially in
habit from Mesozoic examples of that genus the provisional name
Strobilites[401] is suggested. The type-specimens are long and narrow spikes
or loose strobili, 8–16 cm. long and 2–2·6 cm. broad; a stout axis bears
spirally disposed bracts 8–10 mm. long attached by a slender decurrent
pedicel expanded distally into a fan-shaped laciniate lamina with a convex
upper face, and there are said to be two seeds attached to the sides of each
pedicel (fig. 434). The oval seeds appear to be platyspermic and resemble
Samaropsis fluitans Daws. Two of the strobili figured by Renault are
attached at right angles to a second axis, a habit suggesting comparison with
that of a large compound frond. Renault is inclined to regard these fertile
shoots as cycadean and suggests a possible connexion with the Permian
stems Ptychoxylon or Poroxylon, both of which are known to have
that as additional data are obtained it will be found that Pteridosperms
played no inconsiderable part in the vegetation of Gondwana Land.
Fig. 434. Strobilites Milleryensis. (Natural size; after Renault.)
Strobilites. Schimper and Mougeot.
Strobilites Milleryensis (Renault).
This species, from the Permian of France, was placed by Renault in
Cycadospadix[400], but having regard to the fact that it differs essentially in
habit from Mesozoic examples of that genus the provisional name
Strobilites[401] is suggested. The type-specimens are long and narrow spikes
or loose strobili, 8–16 cm. long and 2–2·6 cm. broad; a stout axis bears
spirally disposed bracts 8–10 mm. long attached by a slender decurrent
pedicel expanded distally into a fan-shaped laciniate lamina with a convex
upper face, and there are said to be two seeds attached to the sides of each
pedicel (fig. 434). The oval seeds appear to be platyspermic and resemble
Samaropsis fluitans Daws. Two of the strobili figured by Renault are
attached at right angles to a second axis, a habit suggesting comparison with
that of a large compound frond. Renault is inclined to regard these fertile
shoots as cycadean and suggests a possible connexion with the Permian
stems Ptychoxylon or Poroxylon, both of which are known to have
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produced fairly numerous branches. In habit the spikes are similar to some
of the longer examples of Cordaianthus, but their preservation is not
sufficiently good to afford accurate information as to the relation of seed to
sporophyll. Strobilites Milleryensis is, perhaps, more likely to be the fertile
branch of a compound frond of a Pteridosperm, and it is significant that the
seeds have been found in association with Callipteris leaves.
COLPOXYLON. Brongniart.
Colpoxylon aeduense Brongniart. The genus was founded by
Brongniart[402] on a piece of stem 15 cm. in diameter from the Permian of
the Autun district and regarded by him as a distinct type, with certain
resemblances to recent Cycads. A thick section in the British Museum, 13
cm. in diameter (fig. 435, A), illustrates the main anatomical features
described by Renault[403], to whom our knowledge of the genus is chiefly
due. There are two large steles of irregular outline closely resembling those
of Medullosa Leuckarti (cf. fig. 416, H); each consists of a band of
secondary xylem with broad medullary rays and a narrow zone of phloem
enclosing a central region composed of parenchyma, in which strands of
primary tracheids, both reticulate and spiral, pursue a more or less
horizontal course, associated with a few small groups of vertical xylem-
strands at the inner edge of the secondary wood. The manoxylic nature of
the wood is clearly shown in fig. 436; the continuous ink-line marks the
position of the cambium and the dots show the internal protoxylem.
Homogeneous parenchyma surrounds the steles and beyond this is crushed
tissue containing large secretory canals and nests of stereome fibres either
as separate groups or in contact with the canals (fig. 435, C). In the same
peripheral tissue occur scattered collateral vascular bundles (fig. 435, D)
identical with those of Myeloxylon. The outer cortex of the stem is marked
off from the more homogeneous inner region by a fairly distinct line where
there is some indication of periderm. The anatomical features are clearly
shown in fig. 436, a photograph from a section in Dr Kidston’s collection.
At a is an imperfectly preserved vascular bundle with a crescentic group of
secondary xylem which is probably a leaf-trace that has just emerged from
the secondary cylinder. Renault speaks of these more or less circular strands
as possibly connected with reproductive shoots, but it is more probable that
they are homologous with the strands in the pericycle and inner cortex of
Medullosa and represent leaf-traces before division into smaller collateral
of the longer examples of Cordaianthus, but their preservation is not
sufficiently good to afford accurate information as to the relation of seed to
sporophyll. Strobilites Milleryensis is, perhaps, more likely to be the fertile
branch of a compound frond of a Pteridosperm, and it is significant that the
seeds have been found in association with Callipteris leaves.
COLPOXYLON. Brongniart.
Colpoxylon aeduense Brongniart. The genus was founded by
Brongniart[402] on a piece of stem 15 cm. in diameter from the Permian of
the Autun district and regarded by him as a distinct type, with certain
resemblances to recent Cycads. A thick section in the British Museum, 13
cm. in diameter (fig. 435, A), illustrates the main anatomical features
described by Renault[403], to whom our knowledge of the genus is chiefly
due. There are two large steles of irregular outline closely resembling those
of Medullosa Leuckarti (cf. fig. 416, H); each consists of a band of
secondary xylem with broad medullary rays and a narrow zone of phloem
enclosing a central region composed of parenchyma, in which strands of
primary tracheids, both reticulate and spiral, pursue a more or less
horizontal course, associated with a few small groups of vertical xylem-
strands at the inner edge of the secondary wood. The manoxylic nature of
the wood is clearly shown in fig. 436; the continuous ink-line marks the
position of the cambium and the dots show the internal protoxylem.
Homogeneous parenchyma surrounds the steles and beyond this is crushed
tissue containing large secretory canals and nests of stereome fibres either
as separate groups or in contact with the canals (fig. 435, C). In the same
peripheral tissue occur scattered collateral vascular bundles (fig. 435, D)
identical with those of Myeloxylon. The outer cortex of the stem is marked
off from the more homogeneous inner region by a fairly distinct line where
there is some indication of periderm. The anatomical features are clearly
shown in fig. 436, a photograph from a section in Dr Kidston’s collection.
At a is an imperfectly preserved vascular bundle with a crescentic group of
secondary xylem which is probably a leaf-trace that has just emerged from
the secondary cylinder. Renault speaks of these more or less circular strands
as possibly connected with reproductive shoots, but it is more probable that
they are homologous with the strands in the pericycle and inner cortex of
Medullosa and represent leaf-traces before division into smaller collateral
Page 182
strands. Renault describes the stem as possessing seven vascular cylinders
in the apical region and suggests branching of the main axis as the cause of
the increase in number: there is, however, no evidence to support such
correlation. The two steles seen in fig. 435, A, become merged at a lower
level into a single stele of sinuous form (fig. 435, B).
Fig. 435. Colpoxylon aeduense. A. Diagram of a transverse section of a
specimen in the British Museum. (V. 9393. ½ nat. size.) B. Stele;
much reduced from Renault’s figure. C, D. Secretory canal with
fibres and collateral vascular bundle (Kidston Coll., 1946).
in the apical region and suggests branching of the main axis as the cause of
the increase in number: there is, however, no evidence to support such
correlation. The two steles seen in fig. 435, A, become merged at a lower
level into a single stele of sinuous form (fig. 435, B).
Fig. 435. Colpoxylon aeduense. A. Diagram of a transverse section of a
specimen in the British Museum. (V. 9393. ½ nat. size.) B. Stele;
much reduced from Renault’s figure. C, D. Secretory canal with
fibres and collateral vascular bundle (Kidston Coll., 1946).
Page 183
Fig. 436. Colpoxylon aeduense. Transverse section of half of the stem; a,
stele of branch. Slightly enlarged. (Kidston Coll., 1946.)
Beyond the facts furnished by the leaf-trace bundles in the outer cortex
and the occurrence of two large scars about 5 cm. in breadth on a stem
figured by Renault, we have no positive information as to the form of the
leaves or the structure of the reproductive organs. There is little doubt that
the fronds were large and compound like those of most species of
Medullosa. There is, however, some slight evidence that Alethopteris
Grandini Brongn. and seeds of the Pachytesta type (fig. 497) were borne on
Colpoxylon stems; this rests solely on the association in the Loire coal-
basin[404] of Alethopteris fronds with stems presenting structural
resemblances to Colpoxylon aeduense.
The striking resemblance between Colpoxylon and Medullosa Leuckarti
has led certain authors[405] to propose the substitution of Medullosa for
Colpoxylon. The resemblances though close are hardly sufficient to warrant
this course. In Colpoxylon the stelar system is simpler; there is no central
region with star- or plate-rings as in Medullosa Leuckarti but, as in
Medullosa anglica, the vascular tissue consists only of large steles without a
medullary system. Colpoxylon differs from M. anglica in the reduction in
some parts of the stem of the vascular system to a single stele and,
moreover, the primary portion of the steles is much more parenchymatous
in structure and contains more irregularly anastomosing tracheal strands
than is the case in M. anglica.
stele of branch. Slightly enlarged. (Kidston Coll., 1946.)
Beyond the facts furnished by the leaf-trace bundles in the outer cortex
and the occurrence of two large scars about 5 cm. in breadth on a stem
figured by Renault, we have no positive information as to the form of the
leaves or the structure of the reproductive organs. There is little doubt that
the fronds were large and compound like those of most species of
Medullosa. There is, however, some slight evidence that Alethopteris
Grandini Brongn. and seeds of the Pachytesta type (fig. 497) were borne on
Colpoxylon stems; this rests solely on the association in the Loire coal-
basin[404] of Alethopteris fronds with stems presenting structural
resemblances to Colpoxylon aeduense.
The striking resemblance between Colpoxylon and Medullosa Leuckarti
has led certain authors[405] to propose the substitution of Medullosa for
Colpoxylon. The resemblances though close are hardly sufficient to warrant
this course. In Colpoxylon the stelar system is simpler; there is no central
region with star- or plate-rings as in Medullosa Leuckarti but, as in
Medullosa anglica, the vascular tissue consists only of large steles without a
medullary system. Colpoxylon differs from M. anglica in the reduction in
some parts of the stem of the vascular system to a single stele and,
moreover, the primary portion of the steles is much more parenchymatous
in structure and contains more irregularly anastomosing tracheal strands
than is the case in M. anglica.
Page 184
The alteration in the pattern formed by the vascular system at different
levels in some Medullosan stems, especially in Colpoxylon, may be
compared with the varying disposition of the vascular strands in the thick
dorsiventral rhizomes of Polypodium heracleum Kunz. and P. quercifolium
L. In the rhizome of P. heracleum there are two vascular systems, an outer,
cortical, system in the form of a hollow cylinder composed of a lattice-work
with polygonal meshes from which branches are given off to the roots, and
a more complex medullary system that is concerned with the emission of
leaf-traces. As shown by a series of drawings reproduced in an account by
Klein[406] of the anatomy of these species of Polypodium, the inner system
of steles consists of two cylinders connected towards the upper surface of
the stem by a rounded arch of vascular strands; nearer the leaf-base the two
cylinders meet and eventually a larger cylinder is produced partly from the
upper halves of the two cylinders of the previous section and in part from
the connecting arch: the remains of the two smaller cylinders become
connected with the outer vascular system. These and other changes suggest
comparison with Colpoxylon as also with the stelar changes in the stem of
Ptychoxylon. The comparison cannot be carried beyond the grosser features
and is chiefly interesting as affording a further illustration of a similarity in
plan between some recent Ferns and extinct Pteridosperms and other
Palaeozoic genera.
levels in some Medullosan stems, especially in Colpoxylon, may be
compared with the varying disposition of the vascular strands in the thick
dorsiventral rhizomes of Polypodium heracleum Kunz. and P. quercifolium
L. In the rhizome of P. heracleum there are two vascular systems, an outer,
cortical, system in the form of a hollow cylinder composed of a lattice-work
with polygonal meshes from which branches are given off to the roots, and
a more complex medullary system that is concerned with the emission of
leaf-traces. As shown by a series of drawings reproduced in an account by
Klein[406] of the anatomy of these species of Polypodium, the inner system
of steles consists of two cylinders connected towards the upper surface of
the stem by a rounded arch of vascular strands; nearer the leaf-base the two
cylinders meet and eventually a larger cylinder is produced partly from the
upper halves of the two cylinders of the previous section and in part from
the connecting arch: the remains of the two smaller cylinders become
connected with the outer vascular system. These and other changes suggest
comparison with Colpoxylon as also with the stelar changes in the stem of
Ptychoxylon. The comparison cannot be carried beyond the grosser features
and is chiefly interesting as affording a further illustration of a similarity in
plan between some recent Ferns and extinct Pteridosperms and other
Palaeozoic genera.
Page 185
Fig. 437. Rhexoxylon africanum. Transverse section of stem showing
peripheral steles and central (c) stele. (After Bancroft; × 2.)
RHEXOXYLON. Bancroft.
Rhexoxylon africanum Bancroft. The genus Rhexoxylon was instituted for
a new type of stem represented by a single incomplete specimen from the
Karroo series of South Africa: its precise geological horizon is not known
but it may be referred provisionally to the lower or Palaeozoic portion of
the series. Though our knowledge of the morphological features of the type-
species is far from complete owing in part to the method of preservation of
peripheral steles and central (c) stele. (After Bancroft; × 2.)
RHEXOXYLON. Bancroft.
Rhexoxylon africanum Bancroft. The genus Rhexoxylon was instituted for
a new type of stem represented by a single incomplete specimen from the
Karroo series of South Africa: its precise geological horizon is not known
but it may be referred provisionally to the lower or Palaeozoic portion of
the series. Though our knowledge of the morphological features of the type-
species is far from complete owing in part to the method of preservation of
Page 186
the specimen and in part to the destruction of the outer portion of the
vascular tissue and the whole of the cortex, Miss Bancroft’s careful
description[407] demonstrates the existence of characters which justify the
employment of a new generic name. Rhexoxylon is more nearly related to
the Medulloseae than to any other group and is particularly interesting as
the first recorded example of this group from the Southern Hemisphere.
Fig. 437 shows a transverse section (7 × 5 cm.) of the stem. The ground-
tissue consists of fairly large-celled parenchyma with sclerous nests and a
few bands of periderm. At the periphery of the stem are radially disposed
groups of vascular tissue varying in size and to some extent in shape.
Unfortunately the stem is incomplete and it is impossible to say how much
vascular or other tissue originally existed beyond the present corroded edge.
The vascular groups, or steles as they may legitimately be called, follow a
vertical course through the length of the block (6·5 cm.) and afford only
slight evidence of branching or anastomosing. A close examination of the
steles shows that they consist of portions of two series, an inner and outer
set; there is also a curved vascular band in the central ground-tissue (fig.
437, c) and some isolated and scattered patches of vascular elements. Each
stele of the inner series is made up of two parts, an outer smaller and
normally orientated group of secondary xylem and a larger inversely
orientated inner group of identical structure. A single stele of the inner
series is shown in fig. 438, B, C; the larger inner portion consists of slightly
divergent rows of tracheids and uniseriate medullary rays and is separated
from the smaller portion by a narrow space, a, occupied by crushed tissue
which may correspond to the ‘partial pith’ or primary xylem of a
Medullosan stele. The two groups of xylem are no doubt the products of
two cambium arcs, the protoxylem of each group being situated on the flat
inner face. The cambium and phloem are represented only by crushed
brown cells on the curved outer edge of the xylem. The separate
individuality of the two portions of each stele is indicated not only by the
presence of the ‘partial pith’ but by the discontinuity of the tissue at the
ends of the narrow space. The tracheids seen at b, fig. C, are in oblique
longitudinal section and are probably being detached to form a leaf-trace.
This type of stele may be compared with the steles of Medullosa Solmsi
(fig. 416, L) but those of Rhexoxylon differ in the lack of continuity of the
secondary xylem round the narrow band of crushed primary xylem. The
other steles of the inner ring exhibit the same dual nature though with local
vascular tissue and the whole of the cortex, Miss Bancroft’s careful
description[407] demonstrates the existence of characters which justify the
employment of a new generic name. Rhexoxylon is more nearly related to
the Medulloseae than to any other group and is particularly interesting as
the first recorded example of this group from the Southern Hemisphere.
Fig. 437 shows a transverse section (7 × 5 cm.) of the stem. The ground-
tissue consists of fairly large-celled parenchyma with sclerous nests and a
few bands of periderm. At the periphery of the stem are radially disposed
groups of vascular tissue varying in size and to some extent in shape.
Unfortunately the stem is incomplete and it is impossible to say how much
vascular or other tissue originally existed beyond the present corroded edge.
The vascular groups, or steles as they may legitimately be called, follow a
vertical course through the length of the block (6·5 cm.) and afford only
slight evidence of branching or anastomosing. A close examination of the
steles shows that they consist of portions of two series, an inner and outer
set; there is also a curved vascular band in the central ground-tissue (fig.
437, c) and some isolated and scattered patches of vascular elements. Each
stele of the inner series is made up of two parts, an outer smaller and
normally orientated group of secondary xylem and a larger inversely
orientated inner group of identical structure. A single stele of the inner
series is shown in fig. 438, B, C; the larger inner portion consists of slightly
divergent rows of tracheids and uniseriate medullary rays and is separated
from the smaller portion by a narrow space, a, occupied by crushed tissue
which may correspond to the ‘partial pith’ or primary xylem of a
Medullosan stele. The two groups of xylem are no doubt the products of
two cambium arcs, the protoxylem of each group being situated on the flat
inner face. The cambium and phloem are represented only by crushed
brown cells on the curved outer edge of the xylem. The separate
individuality of the two portions of each stele is indicated not only by the
presence of the ‘partial pith’ but by the discontinuity of the tissue at the
ends of the narrow space. The tracheids seen at b, fig. C, are in oblique
longitudinal section and are probably being detached to form a leaf-trace.
This type of stele may be compared with the steles of Medullosa Solmsi
(fig. 416, L) but those of Rhexoxylon differ in the lack of continuity of the
secondary xylem round the narrow band of crushed primary xylem. The
other steles of the inner ring exhibit the same dual nature though with local
Page 187
modifications. In the stele seen in fig. 438, B, there is a close approach to a
continuous cylinder of secondary xylem especially on the right-hand side.
External to the inner series are several portions of normally orientated
secondary xylem-groups (fig. 437): these probably represent a second series
of steles separated from the inner series by a narrow crushed arc of tissue
on which the protoxylem strands of the outer groups abut. The xylem of the
outer steles agrees in its normal orientation with the outer and smaller part
of the inner steles and, as there is no accompanying group of inversely
orientated xylem corresponding to the larger mass of secondary xylem of
the inner series, the outer strands are designated partial steles. The central
stele consists of two curved irregular bands composed of vertically and
obliquely running tracheids: the central part of this stele consists of crushed
tissue that probably represents primary xylem like that between the two
parts of each of the peripheral steles.
Fig. 438. Rhexoxylon africanum. A, radial wall of tracheid; B, C,
peripheral steles; a, primary portion of stele; b, lateral strand.
(After Bancroft.)
Rhexoxylon differs from the usual Medullosan type in the structure of the
secondary xylem which is composed of tracheids with an Araucarian form
of pitting: there are usually two alternate rows of contiguous pits (fig. 438,
A) and occasionally one or three rows. The medullary rays are uniseriate
and 3 to 15 cells in depth, a feature characteristic of coniferous wood and
not of the wood of the Medulloseae.
In the absence of more complete information as to the anatomical
structure of this stem and of all information as to the leaves or reproductive
organs it is impossible to fix with precision the systematic position of the
continuous cylinder of secondary xylem especially on the right-hand side.
External to the inner series are several portions of normally orientated
secondary xylem-groups (fig. 437): these probably represent a second series
of steles separated from the inner series by a narrow crushed arc of tissue
on which the protoxylem strands of the outer groups abut. The xylem of the
outer steles agrees in its normal orientation with the outer and smaller part
of the inner steles and, as there is no accompanying group of inversely
orientated xylem corresponding to the larger mass of secondary xylem of
the inner series, the outer strands are designated partial steles. The central
stele consists of two curved irregular bands composed of vertically and
obliquely running tracheids: the central part of this stele consists of crushed
tissue that probably represents primary xylem like that between the two
parts of each of the peripheral steles.
Fig. 438. Rhexoxylon africanum. A, radial wall of tracheid; B, C,
peripheral steles; a, primary portion of stele; b, lateral strand.
(After Bancroft.)
Rhexoxylon differs from the usual Medullosan type in the structure of the
secondary xylem which is composed of tracheids with an Araucarian form
of pitting: there are usually two alternate rows of contiguous pits (fig. 438,
A) and occasionally one or three rows. The medullary rays are uniseriate
and 3 to 15 cells in depth, a feature characteristic of coniferous wood and
not of the wood of the Medulloseae.
In the absence of more complete information as to the anatomical
structure of this stem and of all information as to the leaves or reproductive
organs it is impossible to fix with precision the systematic position of the
Page 188
genus. It is, however, clear that Rhexoxylon is closely connected with
Medullosa in certain features though in the structure of the wood it exhibits
important peculiarities. The imperfectly known stem Cladoxylon
Kidstoni[408] shows a fairly close agreement with the African plant in the
form of the steles (fig. 460) but the pitting is scalariform.
SUTCLIFFIA. Scott.
Sutcliffia insignis Scott.
The generic name Sutcliffia was given by Dr Scott[409] to a peculiar type
of stem from the Lower Coal Measures of Shore, Lancashire, in recognition
of the valuable services rendered to Palaeobotany by the late Mr W. H.
Sutcliffe, the owner of the colliery from which several new types of plants
have been obtained. Two stems are recorded, the type-specimen and a more
recently discovered stem, also from Shore, described by Miss de Fraine[410],
which differs in several particulars from Dr Scott’s species. In view of the
well-marked peculiarities of the second stem it is convenient to speak of it
as forma β instead of including it without a distinctive epithet in Sutcliffia
insignis. We know nothing of the reproductive organs of the genus.
1. Sutcliffia insignis, forma α.
This consists of a piece of stem approximately 12 × 7 cm. in diameter
characterised by a broad cortex of parenchyma with secretory sacs and
ducts and strands of mechanical tissue (fig. 439, A). Decurrent and massive
leaf-bases form a prominent feature as in the stem of Medullosa anglica.
The stele, though compressed before petrifaction, was probably not quite
cylindrical but more or less polygonal or broadly triangular in section; it
consists of groups of large primary tracheids (350μ in diameter) with
numerous bordered pits (fig. 439, B, and fig. 440) embedded in an
anastomosing system of parenchyma containing scattered secretory sacs, a
type of protostele like that of Heterangium and Medullosa anglica except in
the possession of exarch protoxylem strands. The metaxylem tracheids
contiguous to the external protoxylem elements have a dense spiral or
scalariform type of pitting. In the lower part of the stem the primary xylem
is enclosed by a cambium which has added a few secondary tracheids (120μ
in diameter), but in the upper part of the specimen the cambium is only
partially developed and the addition of secondary xylem has hardly begun
Medullosa in certain features though in the structure of the wood it exhibits
important peculiarities. The imperfectly known stem Cladoxylon
Kidstoni[408] shows a fairly close agreement with the African plant in the
form of the steles (fig. 460) but the pitting is scalariform.
SUTCLIFFIA. Scott.
Sutcliffia insignis Scott.
The generic name Sutcliffia was given by Dr Scott[409] to a peculiar type
of stem from the Lower Coal Measures of Shore, Lancashire, in recognition
of the valuable services rendered to Palaeobotany by the late Mr W. H.
Sutcliffe, the owner of the colliery from which several new types of plants
have been obtained. Two stems are recorded, the type-specimen and a more
recently discovered stem, also from Shore, described by Miss de Fraine[410],
which differs in several particulars from Dr Scott’s species. In view of the
well-marked peculiarities of the second stem it is convenient to speak of it
as forma β instead of including it without a distinctive epithet in Sutcliffia
insignis. We know nothing of the reproductive organs of the genus.
1. Sutcliffia insignis, forma α.
This consists of a piece of stem approximately 12 × 7 cm. in diameter
characterised by a broad cortex of parenchyma with secretory sacs and
ducts and strands of mechanical tissue (fig. 439, A). Decurrent and massive
leaf-bases form a prominent feature as in the stem of Medullosa anglica.
The stele, though compressed before petrifaction, was probably not quite
cylindrical but more or less polygonal or broadly triangular in section; it
consists of groups of large primary tracheids (350μ in diameter) with
numerous bordered pits (fig. 439, B, and fig. 440) embedded in an
anastomosing system of parenchyma containing scattered secretory sacs, a
type of protostele like that of Heterangium and Medullosa anglica except in
the possession of exarch protoxylem strands. The metaxylem tracheids
contiguous to the external protoxylem elements have a dense spiral or
scalariform type of pitting. In the lower part of the stem the primary xylem
is enclosed by a cambium which has added a few secondary tracheids (120μ
in diameter), but in the upper part of the specimen the cambium is only
partially developed and the addition of secondary xylem has hardly begun
Page 189
(fig. 440). A narrow band of secondary phloem was recognised in places
consisting of small-celled parenchyma with some sieve-tubes and
medullary rays continuous internally with the parenchyma of the primary
stele. In close association and occasionally in organic connexion with the
surface of the stele are several tangentially elongated and large groups of
vascular tissue associated with smaller oval strands varying considerably in
size. These groups, designated meristeles (fig. 439, A), are identical in
structure with the main stele and are occasionally invested by a feebly
developed zone of secondary xylem and phloem. The meristeles are
detached at intervals from the parent stele around which they form by
anastomoses an irregular network: the larger meristeles give off smaller
strands and from these the actual leaf-traces are produced by subdivision. It
appears, however, that in this type the meristeles are not completely used up
in the production of the leaf-traces, portions of them behaving as cauline
vascular strands. A protoxylem of a meristele still attached to the central
protostele occupies an internal position, and at a higher level, as separation
of the meristele is effected, the spiral tracheids occur on the inner face. New
meristeles are given off at intervals from the main stele ‘to compensate for
those parts of the reticulum which were used up in the formation of leaf-
trace strands[411].’ The meristeles form the starting-point for the leaf-traces,
an intermediate system between the main stele and the actual leaf-traces;
they differ, therefore, from the parent leaf-traces of Medullosa anglica,
which are completely used up by repeated subdivision. Moreover in
Sutcliffia the leaf-bundles are concentric and not collateral.
consisting of small-celled parenchyma with some sieve-tubes and
medullary rays continuous internally with the parenchyma of the primary
stele. In close association and occasionally in organic connexion with the
surface of the stele are several tangentially elongated and large groups of
vascular tissue associated with smaller oval strands varying considerably in
size. These groups, designated meristeles (fig. 439, A), are identical in
structure with the main stele and are occasionally invested by a feebly
developed zone of secondary xylem and phloem. The meristeles are
detached at intervals from the parent stele around which they form by
anastomoses an irregular network: the larger meristeles give off smaller
strands and from these the actual leaf-traces are produced by subdivision. It
appears, however, that in this type the meristeles are not completely used up
in the production of the leaf-traces, portions of them behaving as cauline
vascular strands. A protoxylem of a meristele still attached to the central
protostele occupies an internal position, and at a higher level, as separation
of the meristele is effected, the spiral tracheids occur on the inner face. New
meristeles are given off at intervals from the main stele ‘to compensate for
those parts of the reticulum which were used up in the formation of leaf-
trace strands[411].’ The meristeles form the starting-point for the leaf-traces,
an intermediate system between the main stele and the actual leaf-traces;
they differ, therefore, from the parent leaf-traces of Medullosa anglica,
which are completely used up by repeated subdivision. Moreover in
Sutcliffia the leaf-bundles are concentric and not collateral.
Page 190
Fig. 439.
Sutcliffia insignia Scott. A, B, E, forma α. (After Scott.) C, D, forma β.
(After de Fraine.)
A. Transverse section of stem; a, b, double rows of leaf-trace bundles.
The larger black masses are the meristeles; the smaller patches
represent bundles derived from the meristeles.
B. Longitudinal section of a radially symmetrical bundle from a leaf-
base.
C. The junction between the primary and secondary xylem.
Sutcliffia insignia Scott. A, B, E, forma α. (After Scott.) C, D, forma β.
(After de Fraine.)
A. Transverse section of stem; a, b, double rows of leaf-trace bundles.
The larger black masses are the meristeles; the smaller patches
represent bundles derived from the meristeles.
B. Longitudinal section of a radially symmetrical bundle from a leaf-
base.
C. The junction between the primary and secondary xylem.
Page 191
D. Vascular system in transverse section: m, m′, meristeles; s, main
stele; e, extrafascicular strands; lt, leaf-traces; c, secondary cortex.
E. Vascular bundle from petiole showing a ring of large sieve-tubes
surrounding the xylem, and portions of stereome strands.
Fig. 440. Sutcliffia insignis. Part of the primary xylem showing on the
upper edge the beginning of secondary growth. (Cambridge
Botany School, 560.)
A conspicuous feature of the stem of forma α is the occurrence of two
double rows of vascular strands stretching across the cortex (fig. 439, A, a,
b). These are interpreted by Scott as downward continuations in the stem of
the inner surface of leaf-bases. The outer cortex of the stem and leaf-bases
has hypodermal strands of stereome which remain separate or rarely
anastomose, and form a superficial zone exactly like that of some species of
Medullosa. The leaf-trace bundles may be radially symmetrical or unilateral
in the arrangement of the xylem which is in all cases completely surrounded
by phloem. Fig. 439, B, shows part of a longitudinal section of a large leaf-
trace bundle: spiral protoxylem elements (px) abut on the phloem (ph) and
stele; e, extrafascicular strands; lt, leaf-traces; c, secondary cortex.
E. Vascular bundle from petiole showing a ring of large sieve-tubes
surrounding the xylem, and portions of stereome strands.
Fig. 440. Sutcliffia insignis. Part of the primary xylem showing on the
upper edge the beginning of secondary growth. (Cambridge
Botany School, 560.)
A conspicuous feature of the stem of forma α is the occurrence of two
double rows of vascular strands stretching across the cortex (fig. 439, A, a,
b). These are interpreted by Scott as downward continuations in the stem of
the inner surface of leaf-bases. The outer cortex of the stem and leaf-bases
has hypodermal strands of stereome which remain separate or rarely
anastomose, and form a superficial zone exactly like that of some species of
Medullosa. The leaf-trace bundles may be radially symmetrical or unilateral
in the arrangement of the xylem which is in all cases completely surrounded
by phloem. Fig. 439, B, shows part of a longitudinal section of a large leaf-
trace bundle: spiral protoxylem elements (px) abut on the phloem (ph) and
Page 192
are succeeded to the left by narrow scalariform and large reticulately pitted
tracheids. In the larger and radially constructed traces there are several
protoxylem-strands distributed over the surface of the xylem, while in the
smaller unilateral traces there may be one or two protoxylem strands. A
characteristic feature of the xylem of the leaf-traces is the admixture of
parenchyma with the tracheids (fig. 439, B, E) and another noteworthy
character is the occurrence of large thin-walled tubes in the phloem
described by Scott as sieve-tubes and compared with the large sieve-tubes
in Marattiaceous leaf-bundles. Immediately internal to the hypoderm is a
row of leaf-bundles (fig. 439, A) each of which is accompanied by stereome
strands.
The petioles, which reach a diameter of 12 cm., contain numerous,
occasionally anastomosing, concentric bundles. Nothing is known of the
fronds as a whole beyond the fact that they are spirally disposed and had
decurrent bases of large dimensions in proportion to the stem.
Sutcliffia insignis, forma β.
This form, described by Miss de Fraine as Sutcliffia insignis[412], is
represented by a stem rather smaller than the type-specimen described by
Scott, though it is probably an older example of the same species. It is
distinguished by a greater development of secondary xylem and phloem
both on the main stele and the meristeles; it differs also in the absence of
the greater part of the cortex and leaf-bases which have been cut off as the
result of the formation of a deep-seated periderm (fig. 439, D, C). The
meristeles are smaller and fewer than in the larger form and are
distinguished by some other peculiarities. At m′ in fig. 439, D, a meristele is
seen attached to the main stele. In Sutcliffia insignis forma α the main stele
is enclosed by an irregular network of subsidiary steles or meristeles and
these form the points of departure of the leaf-traces, but the meristeles are
not completely used up in the process of conversion into leaf-traces. In
Sutcliffia insignis forma β the meristeles agree in structure with the main
stele except in the smaller amount of secondary tissue: they do not,
however, form a network as in forma α but occur as strands parallel to the
central stele, ‘giving off leaf-traces and ultimately dividing up into smaller
strands, often unequal in size, the primary wood of the meristeles being
entirely used up in the production of radially symmetrical or unilateral
tracheids. In the larger and radially constructed traces there are several
protoxylem-strands distributed over the surface of the xylem, while in the
smaller unilateral traces there may be one or two protoxylem strands. A
characteristic feature of the xylem of the leaf-traces is the admixture of
parenchyma with the tracheids (fig. 439, B, E) and another noteworthy
character is the occurrence of large thin-walled tubes in the phloem
described by Scott as sieve-tubes and compared with the large sieve-tubes
in Marattiaceous leaf-bundles. Immediately internal to the hypoderm is a
row of leaf-bundles (fig. 439, A) each of which is accompanied by stereome
strands.
The petioles, which reach a diameter of 12 cm., contain numerous,
occasionally anastomosing, concentric bundles. Nothing is known of the
fronds as a whole beyond the fact that they are spirally disposed and had
decurrent bases of large dimensions in proportion to the stem.
Sutcliffia insignis, forma β.
This form, described by Miss de Fraine as Sutcliffia insignis[412], is
represented by a stem rather smaller than the type-specimen described by
Scott, though it is probably an older example of the same species. It is
distinguished by a greater development of secondary xylem and phloem
both on the main stele and the meristeles; it differs also in the absence of
the greater part of the cortex and leaf-bases which have been cut off as the
result of the formation of a deep-seated periderm (fig. 439, D, C). The
meristeles are smaller and fewer than in the larger form and are
distinguished by some other peculiarities. At m′ in fig. 439, D, a meristele is
seen attached to the main stele. In Sutcliffia insignis forma α the main stele
is enclosed by an irregular network of subsidiary steles or meristeles and
these form the points of departure of the leaf-traces, but the meristeles are
not completely used up in the process of conversion into leaf-traces. In
Sutcliffia insignis forma β the meristeles agree in structure with the main
stele except in the smaller amount of secondary tissue: they do not,
however, form a network as in forma α but occur as strands parallel to the
central stele, ‘giving off leaf-traces and ultimately dividing up into smaller
strands, often unequal in size, the primary wood of the meristeles being
entirely used up in the production of radially symmetrical or unilateral
Page 193
bundles.’ In this respect, as Miss de Fraine points out, forma β agrees more
closely than forma α with Medullosa anglica and supports Scott’s view that
Sutcliffia is a primitive type of Medullosan stem. The leaves were given off
at fairly long intervals as in some species of Medullosa: the leaf-traces are
exarch and similar to those of the type-species. The most striking feature of
the new stem is the presence of a vascular network (fig. 439, D, e) which
encloses both the main steles and the meristeles; it consists of
extrafascicular strands composed of normally orientated bands of secondary
xylem and phloem often assuming a fan-like arrangement and occasionally
almost concentric or inversely orientated. These strands are always
accompanied by short, usually reticulate, tracheids on the inner margin of
the xylem: similar isodiametric tracheids also occur in the pericyclic region.
The extrafascicular strands are believed to be secondary structures
phylogenetically independent of the meristeles and main stele, comparable
with the successive cylinders or arcs of secondary xylem and phloem in
some recent Cycads and in some species of Medullosa[413].
The stele is exarch and roughly triangular; except in the broader zone of
secondary tissue it agrees with the protostele of forma α. The secondary
xylem (fig. 439, C) possesses numerous medullary rays 3–4 cells broad and
of considerable depth: the secondary phloem is characterised by the
presence of thick-walled elements, presumably sieve-tubes, like those of
Medullosa Leuckarti and M. anglica.
The ground-tissue is rich in secretory tissue and the stem-surface, from
which the leaf-bases have been detached, is limited by a wide zone of
secondary tissue produced by a phellogen.
Sutcliffia Williamsoni (Seward).
1876. Myelopteris (pars) Williamson, Phil. Trans. R. Soc. Vol. 166, Pl. ii.
figs. 7, 8; Pl. iv. fig. 17.
1893. Rachiopteris Williamsoni Seward, Ann. Bot. Vol. vii. p. 1.
1894. Rachiopteris Williamsoni Seward, ibid. Vol. viii. p. 207, Pl. xiii.
1906. Sutcliffia Williamsoni Scott, Trans. Linn. Soc. Vol. vii. pt iv. p. 62.
In an account of Myelopteris (= Myeloxylon) published in 1876
Williamson included some sections of petioles from the Lower Coal
Measures which I afterwards with his concurrence transferred to the genus
Rachiopteris as R. Williamsoni. In Rachiopteris Williamsoni the vascular
closely than forma α with Medullosa anglica and supports Scott’s view that
Sutcliffia is a primitive type of Medullosan stem. The leaves were given off
at fairly long intervals as in some species of Medullosa: the leaf-traces are
exarch and similar to those of the type-species. The most striking feature of
the new stem is the presence of a vascular network (fig. 439, D, e) which
encloses both the main steles and the meristeles; it consists of
extrafascicular strands composed of normally orientated bands of secondary
xylem and phloem often assuming a fan-like arrangement and occasionally
almost concentric or inversely orientated. These strands are always
accompanied by short, usually reticulate, tracheids on the inner margin of
the xylem: similar isodiametric tracheids also occur in the pericyclic region.
The extrafascicular strands are believed to be secondary structures
phylogenetically independent of the meristeles and main stele, comparable
with the successive cylinders or arcs of secondary xylem and phloem in
some recent Cycads and in some species of Medullosa[413].
The stele is exarch and roughly triangular; except in the broader zone of
secondary tissue it agrees with the protostele of forma α. The secondary
xylem (fig. 439, C) possesses numerous medullary rays 3–4 cells broad and
of considerable depth: the secondary phloem is characterised by the
presence of thick-walled elements, presumably sieve-tubes, like those of
Medullosa Leuckarti and M. anglica.
The ground-tissue is rich in secretory tissue and the stem-surface, from
which the leaf-bases have been detached, is limited by a wide zone of
secondary tissue produced by a phellogen.
Sutcliffia Williamsoni (Seward).
1876. Myelopteris (pars) Williamson, Phil. Trans. R. Soc. Vol. 166, Pl. ii.
figs. 7, 8; Pl. iv. fig. 17.
1893. Rachiopteris Williamsoni Seward, Ann. Bot. Vol. vii. p. 1.
1894. Rachiopteris Williamsoni Seward, ibid. Vol. viii. p. 207, Pl. xiii.
1906. Sutcliffia Williamsoni Scott, Trans. Linn. Soc. Vol. vii. pt iv. p. 62.
In an account of Myelopteris (= Myeloxylon) published in 1876
Williamson included some sections of petioles from the Lower Coal
Measures which I afterwards with his concurrence transferred to the genus
Rachiopteris as R. Williamsoni. In Rachiopteris Williamsoni the vascular
Page 194
bundles are concentric and not collateral, and are further distinguished from
those of Myeloxylon by the association of parenchyma with the tracheids. In
the arrangement of the bundles and in the structure of the ground-tissue the
petioles of Rachiopteris Williamsoni agree with those of Myeloxylon. An
outstanding feature of the vascular strands of the former is the occurrence at
fairly regular intervals in the peripheral part of the phloem of comparatively
large tubes described by me as secretory canals on the ground that evidence
was furnished of their development by the schizogenous separation of cells
to form a central canal. The canals were compared with the large sieve-
tubes of the Marattiaceae, but with the qualification that ‘their mature form
and their manner of development are strongly suggestive of small secretory
canals.’ Nothing was known as to the stem which bore these petioles until
Scott’s discovery of Sutcliffia with vascular bundles in the cortex and leaf-
bases of the same type as those of Rachiopteris Williamsoni. As Scott says,
there are a few distinguishing features which suggest that R. Williamsoni is
not specifically identical with the petioles of Sutcliffia insignis, though the
agreement is such as to justify the substitution of Sutcliffia for Rachiopteris.
The tubular elements in the phloem which I considered to be secretory
canals are regarded by Scott and Miss de Fraine as sieve-tubes.
Miss de Fraine gives an excellent summary of our knowledge of the
genus and discusses, in the light of the additional facts furnished by the
second stem, the position of Sutcliffia in a phylogenetic series. The new
form strengthens the comparison instituted by Scott between Sutcliffia and
Medullosa and gives support to a close connexion between the Medulloseae
and the Cycadaceae. Scott lays stress on the fact that the Medulloseae,
except Sutcliffia, are polystelic, while the Cycads, at least the adult stems,
are monostelic. The views of Worsdell and other botanists who believe that
the Medulloseae and the Cycads are intimately related are discussed on
another page: in reference to these views Miss de Fraine adds a caveat as to
the danger of attaching excessive importance to evidence based on seedling
anatomy when we are concerned with broad phylogenetic questions. The
stele of a cycadean stem may be derived from a protostelic type such as that
of Sutcliffia by the gradual disappearance of the internal tracheids: in
Sutcliffia, as in some Cycads and species of Medullosa, extrafascicular
strands and cylinders are a characteristic feature and these may well have
arisen independently of the central stele in response to physiological
requirements. From such a type as Sutcliffia evolution may have proceeded
those of Myeloxylon by the association of parenchyma with the tracheids. In
the arrangement of the bundles and in the structure of the ground-tissue the
petioles of Rachiopteris Williamsoni agree with those of Myeloxylon. An
outstanding feature of the vascular strands of the former is the occurrence at
fairly regular intervals in the peripheral part of the phloem of comparatively
large tubes described by me as secretory canals on the ground that evidence
was furnished of their development by the schizogenous separation of cells
to form a central canal. The canals were compared with the large sieve-
tubes of the Marattiaceae, but with the qualification that ‘their mature form
and their manner of development are strongly suggestive of small secretory
canals.’ Nothing was known as to the stem which bore these petioles until
Scott’s discovery of Sutcliffia with vascular bundles in the cortex and leaf-
bases of the same type as those of Rachiopteris Williamsoni. As Scott says,
there are a few distinguishing features which suggest that R. Williamsoni is
not specifically identical with the petioles of Sutcliffia insignis, though the
agreement is such as to justify the substitution of Sutcliffia for Rachiopteris.
The tubular elements in the phloem which I considered to be secretory
canals are regarded by Scott and Miss de Fraine as sieve-tubes.
Miss de Fraine gives an excellent summary of our knowledge of the
genus and discusses, in the light of the additional facts furnished by the
second stem, the position of Sutcliffia in a phylogenetic series. The new
form strengthens the comparison instituted by Scott between Sutcliffia and
Medullosa and gives support to a close connexion between the Medulloseae
and the Cycadaceae. Scott lays stress on the fact that the Medulloseae,
except Sutcliffia, are polystelic, while the Cycads, at least the adult stems,
are monostelic. The views of Worsdell and other botanists who believe that
the Medulloseae and the Cycads are intimately related are discussed on
another page: in reference to these views Miss de Fraine adds a caveat as to
the danger of attaching excessive importance to evidence based on seedling
anatomy when we are concerned with broad phylogenetic questions. The
stele of a cycadean stem may be derived from a protostelic type such as that
of Sutcliffia by the gradual disappearance of the internal tracheids: in
Sutcliffia, as in some Cycads and species of Medullosa, extrafascicular
strands and cylinders are a characteristic feature and these may well have
arisen independently of the central stele in response to physiological
requirements. From such a type as Sutcliffia evolution may have proceeded
Page 195
along two lines; in one direction new types were produced in which
increasing complexity, as represented by a multiplication of steles, was an
outstanding feature. These forms, illustrated by Medullosa anglica and
other more elaborate species, proved inefficient and were unproductive.
Along another line the protostelic condition was maintained though in some
cases extrafascicular strands or cylinders and cortical steles were
superadded: it was this line that led to the recent Cycads.
General considerations suggested by the anatomical features of Medullosa.
A comparison of the stems described under the generic name Medullosa
reveals a considerable range in the grosser anatomical features superadded
to certain fundamental characters denoting a common origin[414]. If
additional data were available giving us a fuller knowledge of individual
plants differences between species would be more clearly defined and
would provide adequate grounds for the institution of new genera for some
of the types now included in the comprehensive genus Medullosa. A
proposal by Dr Lotsy[415] to adopt the names Pecopteromedullosa and
Neuropteromedullosa rests primarily on the relatively unimportant
difference between the fronds associated with certain Medullosan stems
and, as Scott[416] points out, this two-fold division if applied to such a
species as Medullosa Leuckarti would result in its separation from species
which anatomically are clearly of the same generic type. In Medullosa
anglica, one of the oldest and simplest types, there are three steles of equal
importance, and each of them is practically identical with the single stele of
Heterangium. Each stele—as indeed all Medullosan steles—consists of a
strand of primary xylem enclosed by secondary xylem and phloem, and it is
obvious that the development of a constantly increasing cylinder of
secondary conducting tissue about three centres would lead to serious
mechanical difficulty: a stem constructed on the plan of Medullosa anglica
or the smaller M. pusilla could not increase the thickness of its secondary
vascular tissue beyond a certain point without detriment to its efficiency. In
some types this difficulty is partially overcome by the production of
complete concentric cylinders of centrifugally developed conducting tissue
external to an inner system of concentric steles agreeing individually with
those of Heterangium (fig. 415, B). Medullosa anglica, regarded from the
point of view of the architectural efficiency of its vascular system, affords a
increasing complexity, as represented by a multiplication of steles, was an
outstanding feature. These forms, illustrated by Medullosa anglica and
other more elaborate species, proved inefficient and were unproductive.
Along another line the protostelic condition was maintained though in some
cases extrafascicular strands or cylinders and cortical steles were
superadded: it was this line that led to the recent Cycads.
General considerations suggested by the anatomical features of Medullosa.
A comparison of the stems described under the generic name Medullosa
reveals a considerable range in the grosser anatomical features superadded
to certain fundamental characters denoting a common origin[414]. If
additional data were available giving us a fuller knowledge of individual
plants differences between species would be more clearly defined and
would provide adequate grounds for the institution of new genera for some
of the types now included in the comprehensive genus Medullosa. A
proposal by Dr Lotsy[415] to adopt the names Pecopteromedullosa and
Neuropteromedullosa rests primarily on the relatively unimportant
difference between the fronds associated with certain Medullosan stems
and, as Scott[416] points out, this two-fold division if applied to such a
species as Medullosa Leuckarti would result in its separation from species
which anatomically are clearly of the same generic type. In Medullosa
anglica, one of the oldest and simplest types, there are three steles of equal
importance, and each of them is practically identical with the single stele of
Heterangium. Each stele—as indeed all Medullosan steles—consists of a
strand of primary xylem enclosed by secondary xylem and phloem, and it is
obvious that the development of a constantly increasing cylinder of
secondary conducting tissue about three centres would lead to serious
mechanical difficulty: a stem constructed on the plan of Medullosa anglica
or the smaller M. pusilla could not increase the thickness of its secondary
vascular tissue beyond a certain point without detriment to its efficiency. In
some types this difficulty is partially overcome by the production of
complete concentric cylinders of centrifugally developed conducting tissue
external to an inner system of concentric steles agreeing individually with
those of Heterangium (fig. 415, B). Medullosa anglica, regarded from the
point of view of the architectural efficiency of its vascular system, affords a
Page 196
much less promising point d’appui for further evolution than some of the
forms described under Medullosa stellata in which the mechanical impasse
is avoided by the adoption of the cycadean plan as represented by such
genera as Cycas and Macrozamia. The English species Medullosa
centrofilis (fig. 417) affords the first example of a characteristic Medullosan
feature, namely the presence of a small concentric stele in the central region
of the stem: this so-called star-ring differs not only in its smaller dimensions
but in its more cylindrical form from the larger peripheral steles. In the later
Permian species, e.g. Medullosa porosa and M. Solmsi, the single star-ring
of the older M. centrofilis is replaced by a large number of precisely similar
conducting strands. These star-rings are structurally comparable with the
cortical steles of Cycas and, in position, with the medullary system of
bundles in a Macrozamia; they are essentially cauline and take no part in
the emission of leaf-traces. Medullosa Leuckarti (fig. 416, H) resembles in
its vascular plan M. centrofilis, but in this larger stem there are several star-
rings and the enlarged peripheral steles are more or less sinuous. In
Medullosa Solmsi (fig. 416, E) the star-rings are still more numerous and
the main vascular system consists of a double series of concentric steles,
each agreeing with the larger peripheral steles of M. Leuckarti.
Some of the forms included in Medullosa stellata appear to be very
different from M. anglica and M. Leuckarti (cf. fig. 416, F, A, H), but their
similarity is apparent if we imagine Medullosa anglica with only one main
stele (with the addition of star-rings) which is stretched tangentially until it
becomes a long and narrow plate-ring and is then rolled into a hollow
cylinder like that in fig. 416, D. A modification of the tubular type of stele
is seen in Medullosa stellata var. corticata (fig. 416, G) in which the
vascular cylinder is broken up into two or more curved plate-rings, a change
superficially similar to that by which a dictyostele is produced from a
solenostele, but in Medullosa it is not the overlapping of leaf-gaps that is
the cause of the change. A striking feature in the stem of Medullosa stellata
represented in fig. 416, D and F (especially F), is the inequality in breadth
of the centrifugal and centripetal xylem: this inequality is an expression of
the difficulty caused by the presence of an internal as well as an external
addition of secondary conducting tissue. A limit is set to the production of
secondary centripetal xylem by the space available for extension, whereas
there is unlimited room for increase in the case of the centrifugal tissue.
This tendency to a greater development of xylem and phloem on the outer
forms described under Medullosa stellata in which the mechanical impasse
is avoided by the adoption of the cycadean plan as represented by such
genera as Cycas and Macrozamia. The English species Medullosa
centrofilis (fig. 417) affords the first example of a characteristic Medullosan
feature, namely the presence of a small concentric stele in the central region
of the stem: this so-called star-ring differs not only in its smaller dimensions
but in its more cylindrical form from the larger peripheral steles. In the later
Permian species, e.g. Medullosa porosa and M. Solmsi, the single star-ring
of the older M. centrofilis is replaced by a large number of precisely similar
conducting strands. These star-rings are structurally comparable with the
cortical steles of Cycas and, in position, with the medullary system of
bundles in a Macrozamia; they are essentially cauline and take no part in
the emission of leaf-traces. Medullosa Leuckarti (fig. 416, H) resembles in
its vascular plan M. centrofilis, but in this larger stem there are several star-
rings and the enlarged peripheral steles are more or less sinuous. In
Medullosa Solmsi (fig. 416, E) the star-rings are still more numerous and
the main vascular system consists of a double series of concentric steles,
each agreeing with the larger peripheral steles of M. Leuckarti.
Some of the forms included in Medullosa stellata appear to be very
different from M. anglica and M. Leuckarti (cf. fig. 416, F, A, H), but their
similarity is apparent if we imagine Medullosa anglica with only one main
stele (with the addition of star-rings) which is stretched tangentially until it
becomes a long and narrow plate-ring and is then rolled into a hollow
cylinder like that in fig. 416, D. A modification of the tubular type of stele
is seen in Medullosa stellata var. corticata (fig. 416, G) in which the
vascular cylinder is broken up into two or more curved plate-rings, a change
superficially similar to that by which a dictyostele is produced from a
solenostele, but in Medullosa it is not the overlapping of leaf-gaps that is
the cause of the change. A striking feature in the stem of Medullosa stellata
represented in fig. 416, D and F (especially F), is the inequality in breadth
of the centrifugal and centripetal xylem: this inequality is an expression of
the difficulty caused by the presence of an internal as well as an external
addition of secondary conducting tissue. A limit is set to the production of
secondary centripetal xylem by the space available for extension, whereas
there is unlimited room for increase in the case of the centrifugal tissue.
This tendency to a greater development of xylem and phloem on the outer
Page 197
side of the primary portion of the steles is illustrated also in M. Solmsi var.
lignosa (fig. 416, L) where the outer of the two series of peripheral steles
has a much larger proportion of centrifugal xylem. In M. anglica the
secondary xylem on the inner side of the steles is not infrequently broader
than the corresponding tissue on the abaxial side[417]; but this is exceptional
in the genus. A further development of centrifugal conducting tissue without
any corresponding development of centripetal tissue is effected in certain
cases (fig. 416, K, L) by the addition of concentric cylinders of centrifugal
xylem and phloem beyond the original concentric steles. The type
illustrated by Medullosa Solmsi var. lignosa and M. stellata var. gigantea
(fig. 416, L, K) at once suggests comparison with stems of Cycas,
Macrozamia, and Encephalartos, the chief difference being the presence in
Medullosa of an inner series of concentric steles and a central ground-tissue
containing star-rings, though the latter may be regarded as corresponding to
the medullary system of bundles in Macrozamia. In Macrozamia the central
region of the stem is considered to be the pith of a monostelic stem,
whereas in Medullosa the stem is polystelic. In recent cycadean stems it is
not uncommon to find patches of inversely orientated xylem and phloem
internal to one or more of the cylinders of centrifugal vascular tissue. These
abnormal developments are considered by Worsdell[418] to be relics of the
inner portions of concentric steles possessed by the Medullosan ancestors of
recent Cycads. This interpretation affords a means of bringing into closer
relationship the polystelic Medulloseae and the monostelic Cycadaceae, the
apparent simplicity of the latter being the result of the progressive loss of
centripetal xylem and phloem, the normal cycadean cylinder being
therefore regarded as a one-sided remnant of a concentric Medullosan stele.
In other words, the Cycads are descended from polystelic ancestors. As
further evidence in support of this view Worsdell points to the occurrence of
concentric steles in the cortex of Cycas and their occasional presence in the
pith of other genera. Matte[419] has shown that in the seedling stem of
Encephalartos Barteri (fig. 396, K) there are three concentric steles each
similar to a normal Medullosan stele: at a higher level in the axis the steles
become ‘unrolled’ and assume the form of one-sided cylinders of
centrifugal xylem and phloem.
In the peduncles of some recent Cycads, e.g. Stangeria, there is a
tendency towards a somewhat irregular orientation of the collateral bundles
that constitute the vascular cylinder, and tracheids occasionally occur
lignosa (fig. 416, L) where the outer of the two series of peripheral steles
has a much larger proportion of centrifugal xylem. In M. anglica the
secondary xylem on the inner side of the steles is not infrequently broader
than the corresponding tissue on the abaxial side[417]; but this is exceptional
in the genus. A further development of centrifugal conducting tissue without
any corresponding development of centripetal tissue is effected in certain
cases (fig. 416, K, L) by the addition of concentric cylinders of centrifugal
xylem and phloem beyond the original concentric steles. The type
illustrated by Medullosa Solmsi var. lignosa and M. stellata var. gigantea
(fig. 416, L, K) at once suggests comparison with stems of Cycas,
Macrozamia, and Encephalartos, the chief difference being the presence in
Medullosa of an inner series of concentric steles and a central ground-tissue
containing star-rings, though the latter may be regarded as corresponding to
the medullary system of bundles in Macrozamia. In Macrozamia the central
region of the stem is considered to be the pith of a monostelic stem,
whereas in Medullosa the stem is polystelic. In recent cycadean stems it is
not uncommon to find patches of inversely orientated xylem and phloem
internal to one or more of the cylinders of centrifugal vascular tissue. These
abnormal developments are considered by Worsdell[418] to be relics of the
inner portions of concentric steles possessed by the Medullosan ancestors of
recent Cycads. This interpretation affords a means of bringing into closer
relationship the polystelic Medulloseae and the monostelic Cycadaceae, the
apparent simplicity of the latter being the result of the progressive loss of
centripetal xylem and phloem, the normal cycadean cylinder being
therefore regarded as a one-sided remnant of a concentric Medullosan stele.
In other words, the Cycads are descended from polystelic ancestors. As
further evidence in support of this view Worsdell points to the occurrence of
concentric steles in the cortex of Cycas and their occasional presence in the
pith of other genera. Matte[419] has shown that in the seedling stem of
Encephalartos Barteri (fig. 396, K) there are three concentric steles each
similar to a normal Medullosan stele: at a higher level in the axis the steles
become ‘unrolled’ and assume the form of one-sided cylinders of
centrifugal xylem and phloem.
In the peduncles of some recent Cycads, e.g. Stangeria, there is a
tendency towards a somewhat irregular orientation of the collateral bundles
that constitute the vascular cylinder, and tracheids occasionally occur
Page 198
internal to the protoxylem of the individual bundles[420]. Worsdell regards
these features as evidence of a Medullosan ancestry. If the sinuous plate-
rings of a stem of Medullosa Leuckarti (fig. 416, H) were broken up into
separate portions and wholly or in part deprived of the centripetal xylem,
the result would be an arrangement of bundles comparable with that in a
Stangeria peduncle[421]. The scattered centripetal tracheids discovered by
Scott in Stangeria and other cycadean peduncles are interpreted by Scott
and by Worsdell as relics of some ancestral centripetal xylem, but with this
important difference in the point of view; Scott believes that they represent
the almost completely aborted centripetal xylem of a single stele like that of
Lyginopteris, while Worsdell sees in them fragmentary vestiges of the
central primary xylem of two or more Medullosan steles. An abnormal
seedling of Araucaria Bidwillii described by Shaw[422] exhibits features
analogous to those in some cycadean seedlings: within the normal stele a
cambium forms an inversely orientated vascular cylinder which at a lower
level becomes continuous with the outer centrifugal tissue, the whole
vascular system being eventually represented by two concentric steles. The
polystelic stage is a development of a monostelic condition, and the inner or
inverted portion of each of the two concentric steles is derived from an
inversely orientated cylinder in the central region of the root. This abnormal
root does not, however, supply an argument in favour of the derivation of a
monostelic type of stem from one that was polystelic, but it shows a close
relation between the two plans in one organ. The seedling is not altogether
normal in form apart from structure and it is not improbable that the
anatomical abnormality is connected with some pathological cause.
It has been suggested[423] that Worsdell attaches too much phylogenetic
significance to the irregularities in the disposition and form of the vascular
bundles in the peduncle of Stangeria, and the criticism that insufficient
allowance is made for the possible reaction on structure of the special
physiological requirements of reproductive shoots is well founded. Granting
an overestimate of the arguments drawn from the occasional occurrence of
concentric vascular strands, a considerable body of evidence remains in
favour of Worsdell’s main contention.
Mrs Thoday[424] has drawn attention to certain features exhibited by the
inflorescence-axes of Welwitschia, particularly the occurrence of concentric
and inversely orientated bundles, similar to those characteristic of the
these features as evidence of a Medullosan ancestry. If the sinuous plate-
rings of a stem of Medullosa Leuckarti (fig. 416, H) were broken up into
separate portions and wholly or in part deprived of the centripetal xylem,
the result would be an arrangement of bundles comparable with that in a
Stangeria peduncle[421]. The scattered centripetal tracheids discovered by
Scott in Stangeria and other cycadean peduncles are interpreted by Scott
and by Worsdell as relics of some ancestral centripetal xylem, but with this
important difference in the point of view; Scott believes that they represent
the almost completely aborted centripetal xylem of a single stele like that of
Lyginopteris, while Worsdell sees in them fragmentary vestiges of the
central primary xylem of two or more Medullosan steles. An abnormal
seedling of Araucaria Bidwillii described by Shaw[422] exhibits features
analogous to those in some cycadean seedlings: within the normal stele a
cambium forms an inversely orientated vascular cylinder which at a lower
level becomes continuous with the outer centrifugal tissue, the whole
vascular system being eventually represented by two concentric steles. The
polystelic stage is a development of a monostelic condition, and the inner or
inverted portion of each of the two concentric steles is derived from an
inversely orientated cylinder in the central region of the root. This abnormal
root does not, however, supply an argument in favour of the derivation of a
monostelic type of stem from one that was polystelic, but it shows a close
relation between the two plans in one organ. The seedling is not altogether
normal in form apart from structure and it is not improbable that the
anatomical abnormality is connected with some pathological cause.
It has been suggested[423] that Worsdell attaches too much phylogenetic
significance to the irregularities in the disposition and form of the vascular
bundles in the peduncle of Stangeria, and the criticism that insufficient
allowance is made for the possible reaction on structure of the special
physiological requirements of reproductive shoots is well founded. Granting
an overestimate of the arguments drawn from the occasional occurrence of
concentric vascular strands, a considerable body of evidence remains in
favour of Worsdell’s main contention.
Mrs Thoday[424] has drawn attention to certain features exhibited by the
inflorescence-axes of Welwitschia, particularly the occurrence of concentric
and inversely orientated bundles, similar to those characteristic of the
Page 199
seedling of Cycas siamensis[425] described by Matte, and to anatomical
characters occasionally present in adult cycadean stems and normally
represented in Medullosa. She is of opinion that the occurrence in
Welwitschia of certain Medullosan features has a phylogenetic significance.
The differences between the Gnetales, Medulloseae, and Cycadales are
considerable, and it would seem unlikely that the anatomical resemblances
described by Mrs Thoday are of great value as criteria of close relationship.
The comparison of Lagenostoma with gnetalean seeds is alluded to
elsewhere. To the statement that the presence of concentric and inversely
orientated steles in Welwitschia are reminiscent of the polystelic
Medulloseae, Mrs Thoday adds the qualifying remark that the occurrence of
four concentric groups of vascular tissue in the hypocotyl of Welwitschia is
not sufficient to justify the conclusion that the ancestral type was polystelic.
This reservation accords with the contention of Scott and other botanists,
that the occasional occurrence in cycadean seedlings and adult stems of
anatomical features suggestive of polystely does not in itself furnish an
adequate reason for doubting that the apparent monostely of Cycads is
phylogenetically what it seems to be, namely, an indication of monostelic
ancestry. This brings us to the question of a possible monostelic ancestor. It
may be that the Upper Carboniferous genus Sutcliffia affords a clue to the
problem of the origin of the polystelic type illustrated in various forms by
Medullosa. The protostele of Sutcliffia bears a close resemblance to each of
the three steles of Medullosa anglica; the fact that Sutcliffia is exarch and
that Medullosa anglica has mesarch xylem is of secondary importance,
particularly as exarchy is represented within the genus Medullosa. The
extrafascicular strands of xylem and phloem and the accessory strands are
points in which Sutcliffia and Medullosa anglica agree and, as Miss de
Fraine[426] adds, the meristeles of Sutcliffia may be homologous with the
leaf-trace strands of Medullosa. Scott[427] gave expression to the characters
shared by these two types by describing Sutcliffia as the most primitive of
the Medulloseae. It is suggested that the protostelic axis of Sutcliffia may be
regarded as the starting-point of the monostelic Cycads, the central mass of
tracheal tissue being replaced by a parenchymatous pith, while the
extrafascicular and accessory strands arose independently of the central
stele in response to increased physiological demands consequent on the
increase in size of the stem. From the same starting-point evolution may
have progressed along another line through such a type as Medullosa
characters occasionally present in adult cycadean stems and normally
represented in Medullosa. She is of opinion that the occurrence in
Welwitschia of certain Medullosan features has a phylogenetic significance.
The differences between the Gnetales, Medulloseae, and Cycadales are
considerable, and it would seem unlikely that the anatomical resemblances
described by Mrs Thoday are of great value as criteria of close relationship.
The comparison of Lagenostoma with gnetalean seeds is alluded to
elsewhere. To the statement that the presence of concentric and inversely
orientated steles in Welwitschia are reminiscent of the polystelic
Medulloseae, Mrs Thoday adds the qualifying remark that the occurrence of
four concentric groups of vascular tissue in the hypocotyl of Welwitschia is
not sufficient to justify the conclusion that the ancestral type was polystelic.
This reservation accords with the contention of Scott and other botanists,
that the occasional occurrence in cycadean seedlings and adult stems of
anatomical features suggestive of polystely does not in itself furnish an
adequate reason for doubting that the apparent monostely of Cycads is
phylogenetically what it seems to be, namely, an indication of monostelic
ancestry. This brings us to the question of a possible monostelic ancestor. It
may be that the Upper Carboniferous genus Sutcliffia affords a clue to the
problem of the origin of the polystelic type illustrated in various forms by
Medullosa. The protostele of Sutcliffia bears a close resemblance to each of
the three steles of Medullosa anglica; the fact that Sutcliffia is exarch and
that Medullosa anglica has mesarch xylem is of secondary importance,
particularly as exarchy is represented within the genus Medullosa. The
extrafascicular strands of xylem and phloem and the accessory strands are
points in which Sutcliffia and Medullosa anglica agree and, as Miss de
Fraine[426] adds, the meristeles of Sutcliffia may be homologous with the
leaf-trace strands of Medullosa. Scott[427] gave expression to the characters
shared by these two types by describing Sutcliffia as the most primitive of
the Medulloseae. It is suggested that the protostelic axis of Sutcliffia may be
regarded as the starting-point of the monostelic Cycads, the central mass of
tracheal tissue being replaced by a parenchymatous pith, while the
extrafascicular and accessory strands arose independently of the central
stele in response to increased physiological demands consequent on the
increase in size of the stem. From the same starting-point evolution may
have progressed along another line through such a type as Medullosa
Page 200
anglica leading to the more complex Permian species of Medullosa.
Chodat’s view[428] that the Medulloseae are Protocycadaceae, if we include
Sutcliffia as well as Medullosa in the Medulloseae, is probably correct.
There is clear evidence of a close bond of union between recent Cycads and
the Medulloseae, and Sutcliffia offers a possible means of deriving complex
polystelic types from a monostelic ancestor.
Worsdell’s opinion[429] that the stele of Lyginopteris affords evidence of
derivation from a polystelic ancestor and is not homologous with the true
monostele of Heterangium is opposed to the undoubted signs of intimate
connexion exhibited by these genera. The Lyginopterideae are, as Scott[430]
says, a less advanced group than the Medulloseae and, it may be added,
they are more remote from the modern representatives of the Cycadales.
The Lyginopterideae and the Medulloseae are probably offshoots of a
common stock, but the Medulloseae occupy a position farther removed
from the filicinean ancestry than Heterangium and Lyginopteris[431].
The relative meagreness of our knowledge of the reproductive organs of
the Medulloseae gives precedence to anatomical data in phylogenetic
considerations, but the evidence furnished by Trigonocarpus and other
seeds that may fairly be assigned to Medullosan plants is in harmony with
the conclusions based on vegetative characters with regard to a close
affinity between the Medulloseae and Cycads.
The comparative examination of recent Cycads naturally suggested by
any attempt to compare the group as a whole with Palaeozoic types leads to
some apparently contradictory results. The habit of the megasporophyll of
Cycas is usually quoted as a primitive attribute: the close resemblance in
plan and in manner of occurrence on the stem between megasporophylls
and foliage leaves recalls both Ferns and Medullosan fronds. On the other
hand the production of eight body-cells in the pollen-tube of Microcycas[432]
in place of the usual single cell may also be regarded as a primitive
character. It is perhaps possible, as Miss Dorety[433] says, that the
polyspermy may be a case of recurrence and not a direct inheritance.
Microcycas differs from Cycas in having only one vascular cylinder, and if
the presence of several concentric cylinders in Cycas be interpreted as an
indication of a closer connexion with a Medullosan ancestry, the
Microcycas type would represent a more advanced stage in evolution.
Attempts to arrange plants according to a natural sequence are frequently
Chodat’s view[428] that the Medulloseae are Protocycadaceae, if we include
Sutcliffia as well as Medullosa in the Medulloseae, is probably correct.
There is clear evidence of a close bond of union between recent Cycads and
the Medulloseae, and Sutcliffia offers a possible means of deriving complex
polystelic types from a monostelic ancestor.
Worsdell’s opinion[429] that the stele of Lyginopteris affords evidence of
derivation from a polystelic ancestor and is not homologous with the true
monostele of Heterangium is opposed to the undoubted signs of intimate
connexion exhibited by these genera. The Lyginopterideae are, as Scott[430]
says, a less advanced group than the Medulloseae and, it may be added,
they are more remote from the modern representatives of the Cycadales.
The Lyginopterideae and the Medulloseae are probably offshoots of a
common stock, but the Medulloseae occupy a position farther removed
from the filicinean ancestry than Heterangium and Lyginopteris[431].
The relative meagreness of our knowledge of the reproductive organs of
the Medulloseae gives precedence to anatomical data in phylogenetic
considerations, but the evidence furnished by Trigonocarpus and other
seeds that may fairly be assigned to Medullosan plants is in harmony with
the conclusions based on vegetative characters with regard to a close
affinity between the Medulloseae and Cycads.
The comparative examination of recent Cycads naturally suggested by
any attempt to compare the group as a whole with Palaeozoic types leads to
some apparently contradictory results. The habit of the megasporophyll of
Cycas is usually quoted as a primitive attribute: the close resemblance in
plan and in manner of occurrence on the stem between megasporophylls
and foliage leaves recalls both Ferns and Medullosan fronds. On the other
hand the production of eight body-cells in the pollen-tube of Microcycas[432]
in place of the usual single cell may also be regarded as a primitive
character. It is perhaps possible, as Miss Dorety[433] says, that the
polyspermy may be a case of recurrence and not a direct inheritance.
Microcycas differs from Cycas in having only one vascular cylinder, and if
the presence of several concentric cylinders in Cycas be interpreted as an
indication of a closer connexion with a Medullosan ancestry, the
Microcycas type would represent a more advanced stage in evolution.
Attempts to arrange plants according to a natural sequence are frequently
Page 201
frustrated by instances of unequal progress in the development of vegetative
and reproductive organs; one or other set of members lags behind; some
characters point to the retention of primitive traits while others indicate a
marked progressive tendency. It is noteworthy that the Mesozoic
Bennettitales are characterised by a greater simplicity of stem-structure than
is the rule in recent Cycads, and both in their vegetative features and in the
structure of the seeds they are further removed from the Medullosan type.
Fig. 441. Steloxylon Ludwigii. A, surface-view (longitudinal) of stem
showing leaf-bases. (After Solms-Laubach.) B, longitudinal section
showing anastomosing vascular strands. C, steles, the lower one
showing the emission of a leaf-trace. (B, C, after Schenk.)
III. A. STELOXYLEAE.
Steloxylon. Solms-Laubach.
Steloxylon Ludwigii (Goeppert and Stenzel). The genus is founded on a
piece of stem from Siberia, possibly of Permian age though not improbably
older, which was originally described as Medullosa Ludwigii[434]. It is
characterised by numerous cylindrical and band-like vascular strands
and reproductive organs; one or other set of members lags behind; some
characters point to the retention of primitive traits while others indicate a
marked progressive tendency. It is noteworthy that the Mesozoic
Bennettitales are characterised by a greater simplicity of stem-structure than
is the rule in recent Cycads, and both in their vegetative features and in the
structure of the seeds they are further removed from the Medullosan type.
Fig. 441. Steloxylon Ludwigii. A, surface-view (longitudinal) of stem
showing leaf-bases. (After Solms-Laubach.) B, longitudinal section
showing anastomosing vascular strands. C, steles, the lower one
showing the emission of a leaf-trace. (B, C, after Schenk.)
III. A. STELOXYLEAE.
Steloxylon. Solms-Laubach.
Steloxylon Ludwigii (Goeppert and Stenzel). The genus is founded on a
piece of stem from Siberia, possibly of Permian age though not improbably
older, which was originally described as Medullosa Ludwigii[434]. It is
characterised by numerous cylindrical and band-like vascular strands
Page 202
forming an irregular anastomosing system (fig. 441, B) and by crowded
spiral leaf-scars on the exposed face. The appearance presented by the
transverse section figured by these authors, while suggesting comparison
with Medullosa, reveals a distinctive character, namely the absence of a
definite peripheral system of vascular rings such as forms a striking feature
of the continental Medulloseae. A more complete description was
afterwards published by Schenk[435] who recognised more fully the peculiar
features and hinted at the possibility that the species might more
appropriately be regarded as a member of a distinct group. Solms-
Laubach[436] went a step further and instituted the generic name Steloxylon,
and in a later publication gave a fuller account of the anatomical characters.
The complete stem must have reached a diameter of approximately 13 cm.
The homogeneous ground-tissue forms a matrix enclosing an anastomosing
vascular system of cylindrical or oval steles (fig. 441, C). Each strand
consists of a band of secondary xylem tracheids with one or several rows of
circular or oval bordered pits on the radial walls and narrow medullary rays
usually 1–2 cells broad and 1–4 cells deep, though occasionally deeper. No
phloem is preserved. The tissue in the centre of each stele is very
imperfectly preserved, but it is clear that the secondary xylem enclosed a
central region (‘partial pith’) like that in the steles of a Medullosa, doubtless
consisting of primary xylem and conjunctive parenchyma.
The stem is covered with leaf-bases of oval or circular section and
between them are small organs, probably multicellular hairs (fig. 441, A). A
leaf-base consists of an outer zone of strengthening tissue and a
parenchymatous ground-tissue traversed by two or more small vascular
strands which assume various forms. These petiolar strands are simply
portions of the main vascular system which bend outwards at the periphery
of the anastomosing network. The more noteworthy features in which
Steloxylon differs from Medullosa, particularly such species as M. stellata
and M. Leuckarti, are (i) the crowded and comparatively small leaf-bases in
place of the massive decurrent petioles of Medullosa; (ii) the supply of the
leaves by compact branches of the stelar network instead of the bundles
detached as leaf-traces from a stem-stele of Medullosa (the origin of a leaf-
trace in Steloxylon is shown in fig. 441, C); (iii) the absence of a peripheral
system of vascular plate-rings and the irregular distribution of cylindrical
and plate-steles in the ground-tissue. Nothing is known of the reproductive
organs or leaves beyond the structure of the attached leaf-bases. The
spiral leaf-scars on the exposed face. The appearance presented by the
transverse section figured by these authors, while suggesting comparison
with Medullosa, reveals a distinctive character, namely the absence of a
definite peripheral system of vascular rings such as forms a striking feature
of the continental Medulloseae. A more complete description was
afterwards published by Schenk[435] who recognised more fully the peculiar
features and hinted at the possibility that the species might more
appropriately be regarded as a member of a distinct group. Solms-
Laubach[436] went a step further and instituted the generic name Steloxylon,
and in a later publication gave a fuller account of the anatomical characters.
The complete stem must have reached a diameter of approximately 13 cm.
The homogeneous ground-tissue forms a matrix enclosing an anastomosing
vascular system of cylindrical or oval steles (fig. 441, C). Each strand
consists of a band of secondary xylem tracheids with one or several rows of
circular or oval bordered pits on the radial walls and narrow medullary rays
usually 1–2 cells broad and 1–4 cells deep, though occasionally deeper. No
phloem is preserved. The tissue in the centre of each stele is very
imperfectly preserved, but it is clear that the secondary xylem enclosed a
central region (‘partial pith’) like that in the steles of a Medullosa, doubtless
consisting of primary xylem and conjunctive parenchyma.
The stem is covered with leaf-bases of oval or circular section and
between them are small organs, probably multicellular hairs (fig. 441, A). A
leaf-base consists of an outer zone of strengthening tissue and a
parenchymatous ground-tissue traversed by two or more small vascular
strands which assume various forms. These petiolar strands are simply
portions of the main vascular system which bend outwards at the periphery
of the anastomosing network. The more noteworthy features in which
Steloxylon differs from Medullosa, particularly such species as M. stellata
and M. Leuckarti, are (i) the crowded and comparatively small leaf-bases in
place of the massive decurrent petioles of Medullosa; (ii) the supply of the
leaves by compact branches of the stelar network instead of the bundles
detached as leaf-traces from a stem-stele of Medullosa (the origin of a leaf-
trace in Steloxylon is shown in fig. 441, C); (iii) the absence of a peripheral
system of vascular plate-rings and the irregular distribution of cylindrical
and plate-steles in the ground-tissue. Nothing is known of the reproductive
organs or leaves beyond the structure of the attached leaf-bases. The
Page 203
opinion expressed by P. Bertrand[437] that the fossil described by Stenzel as
Asterochlaena (Clepsydropsis) kirgisica is the petiole of Steloxylon was
abandoned after the additional facts published by Solms-Laubach.
As regards the affinities of Steloxylon: the structure of the steles agrees
closely with that of the star- and plate-rings of a Medullosa, while the
pitting of the tracheids is more like that in Medullosa than Cladoxylon. In
the tendency to a more radial than tangential disposition of the band-like
steles Steloxylon recalls Cladoxylon rather than Medullosa, but in
Cladoxylon the vascular system does not form an irregular network as in
Steloxylon. The information as to the structure of the primary xylem is very
meagre, but it points to a closer connexion with Medullosa than with
Cladoxylon. On the whole Steloxylon may perhaps be defined as a genus
allied to the Medulloseae in the anatomical features of the stem more
closely than to other genera, but sufficiently distinct to be excluded from
the Medulloseae as at present understood[438].
Asterochlaena (Clepsydropsis) kirgisica is the petiole of Steloxylon was
abandoned after the additional facts published by Solms-Laubach.
As regards the affinities of Steloxylon: the structure of the steles agrees
closely with that of the star- and plate-rings of a Medullosa, while the
pitting of the tracheids is more like that in Medullosa than Cladoxylon. In
the tendency to a more radial than tangential disposition of the band-like
steles Steloxylon recalls Cladoxylon rather than Medullosa, but in
Cladoxylon the vascular system does not form an irregular network as in
Steloxylon. The information as to the structure of the primary xylem is very
meagre, but it points to a closer connexion with Medullosa than with
Cladoxylon. On the whole Steloxylon may perhaps be defined as a genus
allied to the Medulloseae in the anatomical features of the stem more
closely than to other genera, but sufficiently distinct to be excluded from
the Medulloseae as at present understood[438].
Page 204
Page 205
CHAPTER XXXI.
PTERIDOSPERMS REPRESENTED BY SEED-BEARING
LEAVES ONLY OR LEAVES IN CONSTANT ASSOCIATION
WITH SEEDS.
Before describing other genera represented by petrified vegetative organs
exhibiting in their anatomical features points of contact with the
Medulloseae, a short account is intercalated of some imperfectly known
seed-bearing fronds and seeds belonging to the Pteridosperms but which do
not afford sufficient data to admit of their reference to a more precise
position in a natural classification.
Pecopteris Pluckeneti (Schlotheim).
In the section in Volume ii. devoted to the genus Pecopteris reference was
made to the species P. Pluckeneti[439], further treatment being deferred until
other Pteridosperms had been described. The fern-like fronds originally
described by Schlotheim as Filicites Pluckeneti[440] and afterwards
transferred by Brongniart and other authors to Pecopteris[441] are now
recognised as the leaves of a Pteridosperm. Some doubt has been expressed
as to the specific identity of the specimens figured by Schlotheim and
Brongniart respectively, but Potonié’s examination of the type-specimen of
the earlier author convinced him that Brongniart’s leaves were correctly
named. The large fronds of Pecopteris Pluckeneti are characterised by the
bifurcation of the principal axis which bears opposite pairs of bi- or tri-
pinnate branches and in the angles of the bifurcations of the rachis
undeveloped buds occur on prolongations of the axis, a habit recalling
recent species of Gleichenia[442] (figs. 225 and 226, vol. ii.). The variation in
the form of the pinnules is shown in fig. 442, A, which represents both the
apical portion and parts of pinnae 10 cm. lower on the rachis of a large leaf
from the Coal Measures of Radstock. The species is characteristic of the
Upper Coal Measures and is recorded also from Permian strata. In 1883
Sterzel adopted for this species the generic name Dicksonites because of the
occurrence of shallow circular cups at the end of the lowest lateral vein on
PTERIDOSPERMS REPRESENTED BY SEED-BEARING
LEAVES ONLY OR LEAVES IN CONSTANT ASSOCIATION
WITH SEEDS.
Before describing other genera represented by petrified vegetative organs
exhibiting in their anatomical features points of contact with the
Medulloseae, a short account is intercalated of some imperfectly known
seed-bearing fronds and seeds belonging to the Pteridosperms but which do
not afford sufficient data to admit of their reference to a more precise
position in a natural classification.
Pecopteris Pluckeneti (Schlotheim).
In the section in Volume ii. devoted to the genus Pecopteris reference was
made to the species P. Pluckeneti[439], further treatment being deferred until
other Pteridosperms had been described. The fern-like fronds originally
described by Schlotheim as Filicites Pluckeneti[440] and afterwards
transferred by Brongniart and other authors to Pecopteris[441] are now
recognised as the leaves of a Pteridosperm. Some doubt has been expressed
as to the specific identity of the specimens figured by Schlotheim and
Brongniart respectively, but Potonié’s examination of the type-specimen of
the earlier author convinced him that Brongniart’s leaves were correctly
named. The large fronds of Pecopteris Pluckeneti are characterised by the
bifurcation of the principal axis which bears opposite pairs of bi- or tri-
pinnate branches and in the angles of the bifurcations of the rachis
undeveloped buds occur on prolongations of the axis, a habit recalling
recent species of Gleichenia[442] (figs. 225 and 226, vol. ii.). The variation in
the form of the pinnules is shown in fig. 442, A, which represents both the
apical portion and parts of pinnae 10 cm. lower on the rachis of a large leaf
from the Coal Measures of Radstock. The species is characteristic of the
Upper Coal Measures and is recorded also from Permian strata. In 1883
Sterzel adopted for this species the generic name Dicksonites because of the
occurrence of shallow circular cups at the end of the lowest lateral vein on
Page 206
some of the pinnules which he believed to be sori of the Cyatheaceous type.
The cups have an involute margin and occasionally a small scar in the
centre (fig. 442, B). Stur[443] declined to accept Sterzel’s evidence as
satisfactory and suggested a fungal origin for the sorus-like impressions, a
view, as Sterzel objected, that is rendered improbable by the constant
position of the single cups on several pinnules. The nature of Sterzel’s ‘sori’
has not been demonstrated: it is suggested by Grand’Eury[444] that they mark
the position of microsporangia. Some seed-bearing specimens in Dr
Kidston’s collection show cups, like those figured by Sterzel, on pinnules
from which the seeds have fallen, and it is not improbable that they are the
scars of seeds. In 1905 Grand’Eury published a description and photographs
of specimens of P. Pluckeneti from the St Étienne coal-field showing
hundreds of well-preserved seeds, many of them attached to pinnules
characterised by a very slightly reduced lamina. Some fronds were found to
be entirely fertile, while others bore both sterile and fertile pinnae. The
smallest seeds, 5 mm. long and 3 mm. broad, were found at the tips of
unexpanded leaves: the mature seeds, only slightly larger, agree in their
broadly oval form and narrow marginal ‘wing’ with small examples of
Samaropsis[445]. The seeds were figured by Grand’Eury[446] in an earlier
work as Carpolithes granulatus. They are believed to have hung free from
the lamina, a conclusion based on the position of the seeds relative to the
plane of the pinnule in well-preserved examples. Prof. Zeiller informs me
that he is by no means certain that Grand’Eury’s seed-bearing fronds should
not be referred to Pecopteris Sterzeli; but as that species and P. Pluckeneti
are very closely allied forms and may well have borne the same general
type of fructification, the question of specific difference does not affect the
significance of Grand’Eury’s discovery. A statement was made in vol. ii.[447],
quoted from Grand’Eury, that the fronds of P. Sterzeli were borne on a
Psaronius stem, but Prof. Zeiller told me that in his opinion the fronds and
stem are merely in association and not in organic contact. It is probable that
the Psaronius stem bore fronds of some species of Pecopteris with sori of
the Asterotheca or Scolecopteris type and not seeds. Pecopteris Pluckeneti
and P. Sterzeli are no doubt the fronds of a Pteridosperm[448], but apart from
the seed-impressions there is no evidence as to the nature of the
reproductive organs or stem. The form of the seeds with a fairly thick
sarcotesta, which gives them a winged appearance, suggests a member of
The cups have an involute margin and occasionally a small scar in the
centre (fig. 442, B). Stur[443] declined to accept Sterzel’s evidence as
satisfactory and suggested a fungal origin for the sorus-like impressions, a
view, as Sterzel objected, that is rendered improbable by the constant
position of the single cups on several pinnules. The nature of Sterzel’s ‘sori’
has not been demonstrated: it is suggested by Grand’Eury[444] that they mark
the position of microsporangia. Some seed-bearing specimens in Dr
Kidston’s collection show cups, like those figured by Sterzel, on pinnules
from which the seeds have fallen, and it is not improbable that they are the
scars of seeds. In 1905 Grand’Eury published a description and photographs
of specimens of P. Pluckeneti from the St Étienne coal-field showing
hundreds of well-preserved seeds, many of them attached to pinnules
characterised by a very slightly reduced lamina. Some fronds were found to
be entirely fertile, while others bore both sterile and fertile pinnae. The
smallest seeds, 5 mm. long and 3 mm. broad, were found at the tips of
unexpanded leaves: the mature seeds, only slightly larger, agree in their
broadly oval form and narrow marginal ‘wing’ with small examples of
Samaropsis[445]. The seeds were figured by Grand’Eury[446] in an earlier
work as Carpolithes granulatus. They are believed to have hung free from
the lamina, a conclusion based on the position of the seeds relative to the
plane of the pinnule in well-preserved examples. Prof. Zeiller informs me
that he is by no means certain that Grand’Eury’s seed-bearing fronds should
not be referred to Pecopteris Sterzeli; but as that species and P. Pluckeneti
are very closely allied forms and may well have borne the same general
type of fructification, the question of specific difference does not affect the
significance of Grand’Eury’s discovery. A statement was made in vol. ii.[447],
quoted from Grand’Eury, that the fronds of P. Sterzeli were borne on a
Psaronius stem, but Prof. Zeiller told me that in his opinion the fronds and
stem are merely in association and not in organic contact. It is probable that
the Psaronius stem bore fronds of some species of Pecopteris with sori of
the Asterotheca or Scolecopteris type and not seeds. Pecopteris Pluckeneti
and P. Sterzeli are no doubt the fronds of a Pteridosperm[448], but apart from
the seed-impressions there is no evidence as to the nature of the
reproductive organs or stem. The form of the seeds with a fairly thick
sarcotesta, which gives them a winged appearance, suggests a member of
Page 207
the Medulloseae rather than a plant with seeds like those of Lyginopteris
and Heterangium.
Fig. 442. Pecopteris Pluckeneti. A, apex and lower pinnae (Kidston
Coll., 234); B, pinnule with supposed sorus (after Sterzel); C,
pinnule with seeds (after Zeiller).
Eremopteris artemisaefolia Steinberg with Samaropsis acuta Lindley and
Hutton.
The generic name Eremopteris was instituted by Schimper for a type of
frond from the Coal Measures of Newcastle described by Sternberg as
Sphenopteris artemisaefolia. He included also a second species, E. Neesii,
from the Permian of Bohemia: this was removed by Zeiller to Callipteris.
The type-species of Eremopteris is included in this chapter on the ground
that the almost constant association with the fronds of seeds comparable
with those described by White as Aneimites (Wardia) fertilis affords a
strong argument in favour of assigning Eremopteris artemisaefolia to the
Pteridosperms.
and Heterangium.
Fig. 442. Pecopteris Pluckeneti. A, apex and lower pinnae (Kidston
Coll., 234); B, pinnule with supposed sorus (after Sterzel); C,
pinnule with seeds (after Zeiller).
Eremopteris artemisaefolia Steinberg with Samaropsis acuta Lindley and
Hutton.
The generic name Eremopteris was instituted by Schimper for a type of
frond from the Coal Measures of Newcastle described by Sternberg as
Sphenopteris artemisaefolia. He included also a second species, E. Neesii,
from the Permian of Bohemia: this was removed by Zeiller to Callipteris.
The type-species of Eremopteris is included in this chapter on the ground
that the almost constant association with the fronds of seeds comparable
with those described by White as Aneimites (Wardia) fertilis affords a
strong argument in favour of assigning Eremopteris artemisaefolia to the
Pteridosperms.
Page 208
1826. Sphenopteris artemisaefolia Steinberg, Flor. Vorwelt, Fasc. iv. p.
15, Pl. lvi. fig. 1.
1833. Sphenopteris crithmifolia Lindley and Hutton, Foss. Flor. Vol. i. Pl.
xlvi.
1833. Cardiocarpon acutum, Ibid. Pl. lxxvi.
1869. Eremopteris artemisaefolia Schimper, Trait. Pal. Vég. Vol. i. p. 416.
1914. Samaropsis acuta Kidston, Trans. R. Soc. Edinb. Vol. l. Pt i. p. 156.
The large compound fronds of this species[449] are characterised by the
regular dichotomy of the main branches, a feature frequently met with in
Palaeozoic fern-like leaves: the cuneate or oval-cuneiform pinnules (fig.
443, A, C) vary considerably in breadth from the typical cuneate type of
segment as figured by Brongniart[450] to narrow, almost linear, leaflets like
those of Sphenopteris crithmifolia. Several spreading veins traverse the
lamina. Lindley and Hutton, while admitting a very close resemblance
between their species and S. artemisaefolia, adopted a distinctive name. The
only evidence so far obtained as to the stem of the plant is furnished by
some specimens in the Hutton collection (Newcastle-upon-Tyne) one of
which shows a piece of rhizome bearing several petioles (fig. 443, B): there
are no pinnules attached to the rachises but some occur in close association.
Brongniart noticed the frequent association of Eremopteris fronds with
small seeds, but he regarded it as accidental. Dr Kidston[451] has recently
drawn attention to a note by Prof. Duns published in 1872 on the
juxtaposition of seeds and fronds, and Mr Howse[452] in his Catalogue of the
Hutton plants considers that the seeds were borne on the Eremopteris
leaves; in his synonymy of E. artemisaefolia he includes Cardiocarpon
acutum Lind. and Hutt. as the ‘spore-cases or sporangia.’ The Eremopteris
seeds are of the platyspermic (Samaropsis) type, broadly oval and about 7
mm. long with an obtuse base and two slightly divergent acute processes at
the apex (fig. 444). Some specimens in Dr Kidston’s collection from the
Lower Coal Measures of Midlothian, which were associated with
Eremopteris fronds, are preserved as mummified cuticular membranes and
on microscopical examination they show clearly the presence of a pollen-
chamber. The seeds are of the Samaropsis type. The drawings reproduced in
fig. 444 were made for me by Dr Kidston from two specimens, in his
collection, of exceptionally well-preserved seeds from Midlothian: the
seeds of this species vary considerably in size and form; some are almost
15, Pl. lvi. fig. 1.
1833. Sphenopteris crithmifolia Lindley and Hutton, Foss. Flor. Vol. i. Pl.
xlvi.
1833. Cardiocarpon acutum, Ibid. Pl. lxxvi.
1869. Eremopteris artemisaefolia Schimper, Trait. Pal. Vég. Vol. i. p. 416.
1914. Samaropsis acuta Kidston, Trans. R. Soc. Edinb. Vol. l. Pt i. p. 156.
The large compound fronds of this species[449] are characterised by the
regular dichotomy of the main branches, a feature frequently met with in
Palaeozoic fern-like leaves: the cuneate or oval-cuneiform pinnules (fig.
443, A, C) vary considerably in breadth from the typical cuneate type of
segment as figured by Brongniart[450] to narrow, almost linear, leaflets like
those of Sphenopteris crithmifolia. Several spreading veins traverse the
lamina. Lindley and Hutton, while admitting a very close resemblance
between their species and S. artemisaefolia, adopted a distinctive name. The
only evidence so far obtained as to the stem of the plant is furnished by
some specimens in the Hutton collection (Newcastle-upon-Tyne) one of
which shows a piece of rhizome bearing several petioles (fig. 443, B): there
are no pinnules attached to the rachises but some occur in close association.
Brongniart noticed the frequent association of Eremopteris fronds with
small seeds, but he regarded it as accidental. Dr Kidston[451] has recently
drawn attention to a note by Prof. Duns published in 1872 on the
juxtaposition of seeds and fronds, and Mr Howse[452] in his Catalogue of the
Hutton plants considers that the seeds were borne on the Eremopteris
leaves; in his synonymy of E. artemisaefolia he includes Cardiocarpon
acutum Lind. and Hutt. as the ‘spore-cases or sporangia.’ The Eremopteris
seeds are of the platyspermic (Samaropsis) type, broadly oval and about 7
mm. long with an obtuse base and two slightly divergent acute processes at
the apex (fig. 444). Some specimens in Dr Kidston’s collection from the
Lower Coal Measures of Midlothian, which were associated with
Eremopteris fronds, are preserved as mummified cuticular membranes and
on microscopical examination they show clearly the presence of a pollen-
chamber. The seeds are of the Samaropsis type. The drawings reproduced in
fig. 444 were made for me by Dr Kidston from two specimens, in his
collection, of exceptionally well-preserved seeds from Midlothian: the
seeds of this species vary considerably in size and form; some are almost
Page 209
orbicular and show no distinction between nucule and border (fig. 444, A)
while in others (B) the impression of the flattened and longitudinally
striated sarcotesta is clearly distinguished. Kidston is of opinion that in
younger seeds there is a single apical point replaced in a later stage of
development by two cusps, as seen in figs. A and B, formed by the opening
of the micropylar tube. A ridge in the middle of the flattened surface
indicates the position of the vascular bundles in the principal plane as in
Cardiocarpus. The fully developed seeds are 8–9 mm. long. The correlation
of the seeds represented in figs. 443 and 444 with Eremopteris fronds
furnishes an additional illustration of the impossibility of trusting to
external form as a criterion of affinity, for it is known that seeds of the
Samaropsis type were produced by Pteridosperms with foliage represented
by Eremopteris artemisaefolia and Pecopteris Pluckeneti, also by some
members of the Cordaitales (e.g. fig. 480). Dr Arber[453] has recently
proposed a new generic name Cornucarpus for Cardiocarpon acutum, but
the drawings that he gives of seeds from the Kent coal-field referred to this
species suggest a type distinct from that of Lindley and Hutton. In the
absence of specimens showing actual attachment it is impossible to say how
the seeds were borne, but the analogy of Wardia fertilis and Pecopteris
Pluckeneti lends support to the view that the seeds were attached to
pinnules with a reduced lamina. Eremopteris artemisaefolia occurs in the
Lower and Middle Coal Measures of England: a species recorded by
Kidston from the Calciferous sandstone of Scotland as E. Macconochii[454]
is now believed by that author to be generically distinct[455]. With the
exception of the unsatisfactory specimen reproduced in fig. 443, B, we have
no information with regard to the habit of the stem to which the
Eremopteris leaves were attached.
while in others (B) the impression of the flattened and longitudinally
striated sarcotesta is clearly distinguished. Kidston is of opinion that in
younger seeds there is a single apical point replaced in a later stage of
development by two cusps, as seen in figs. A and B, formed by the opening
of the micropylar tube. A ridge in the middle of the flattened surface
indicates the position of the vascular bundles in the principal plane as in
Cardiocarpus. The fully developed seeds are 8–9 mm. long. The correlation
of the seeds represented in figs. 443 and 444 with Eremopteris fronds
furnishes an additional illustration of the impossibility of trusting to
external form as a criterion of affinity, for it is known that seeds of the
Samaropsis type were produced by Pteridosperms with foliage represented
by Eremopteris artemisaefolia and Pecopteris Pluckeneti, also by some
members of the Cordaitales (e.g. fig. 480). Dr Arber[453] has recently
proposed a new generic name Cornucarpus for Cardiocarpon acutum, but
the drawings that he gives of seeds from the Kent coal-field referred to this
species suggest a type distinct from that of Lindley and Hutton. In the
absence of specimens showing actual attachment it is impossible to say how
the seeds were borne, but the analogy of Wardia fertilis and Pecopteris
Pluckeneti lends support to the view that the seeds were attached to
pinnules with a reduced lamina. Eremopteris artemisaefolia occurs in the
Lower and Middle Coal Measures of England: a species recorded by
Kidston from the Calciferous sandstone of Scotland as E. Macconochii[454]
is now believed by that author to be generically distinct[455]. With the
exception of the unsatisfactory specimen reproduced in fig. 443, B, we have
no information with regard to the habit of the stem to which the
Eremopteris leaves were attached.
Page 210
Fig. 443. Eremopteris artemisaefolia. A, part of a frond with associated
seeds of Samaropsis acuta; B, rhizome with fragments of fronds; C,
pinnule. (Drawn by Mr L. D. Sayers from specimens in the Hutton
Collection, Newcastle. A, B, ⅔ nat. size.)
Fig. 444. Samaropsis acuta. (From drawings by Dr Kidston of
specimens in his collection, 3475 (A), 3316 (B); × 2.)
seeds of Samaropsis acuta; B, rhizome with fragments of fronds; C,
pinnule. (Drawn by Mr L. D. Sayers from specimens in the Hutton
Collection, Newcastle. A, B, ⅔ nat. size.)
Fig. 444. Samaropsis acuta. (From drawings by Dr Kidston of
specimens in his collection, 3475 (A), 3316 (B); × 2.)
Page 211
Fig. 445. Wardia fertilis (White). A, sterile portion of frond; B, D,
enlarged pinnules; C, seed. (After White. A, ca, nat. size; B–D, × 2.)
WARDIA. White.
Wardia fertilis (White). Another example of a fern-like frond bearing
seeds is afforded by specimens from the Lower Pottsville series of Virginia
(correlated with the Millstone grit of British geologists) described by Mr
David White[456] as Aneimites (Wardia) fertilis. The compound fronds
usually referred to the genus Adiantides or Adiantites[457] are characterised
by cuneate pinnules with a thin lamina and forked, slightly divergent veins
(fig. 445, A, D). White discards the name Adiantides in favour of Dawson’s
genus Aneimites on the ground that Goeppert[458], who instituted the former
term, applied it in the first instance to leaves of Ginkgo which he identified
as simple Fern fronds. In spite of this misapplication of the name it has been
constantly used and is well established. The discovery of seeds is, however,
a reason for the adoption of a new generic name, and as White proposed
enlarged pinnules; C, seed. (After White. A, ca, nat. size; B–D, × 2.)
WARDIA. White.
Wardia fertilis (White). Another example of a fern-like frond bearing
seeds is afforded by specimens from the Lower Pottsville series of Virginia
(correlated with the Millstone grit of British geologists) described by Mr
David White[456] as Aneimites (Wardia) fertilis. The compound fronds
usually referred to the genus Adiantides or Adiantites[457] are characterised
by cuneate pinnules with a thin lamina and forked, slightly divergent veins
(fig. 445, A, D). White discards the name Adiantides in favour of Dawson’s
genus Aneimites on the ground that Goeppert[458], who instituted the former
term, applied it in the first instance to leaves of Ginkgo which he identified
as simple Fern fronds. In spite of this misapplication of the name it has been
constantly used and is well established. The discovery of seeds is, however,
a reason for the adoption of a new generic name, and as White proposed
Page 212
Wardia for the seeds it may appropriately be extended to the fronds in place
of the provisional term Aneimites. The seeds which occur at the apices of
slender pedicels on pinnae bearing relatively small pinnules with a reduced
lamina (fig. 445, B, C) are rhomboidal in shape, 4·5 mm. long and 2·5 mm.
broad. The bilaterally symmetrical seeds were probably enclosed, as White
suggests, in a fleshy integument which on pressure became laterally
extended as a wing-like border. In some of the seeds there is an indication
of a ‘slight collapse within the apex of the nutlet,’ which may mean the
presence of a pollen-chamber; but while the preservation is too imperfect to
afford any decisive evidence as to anatomical features, there is no reason to
doubt the conclusion as to the seed-nature of the organs described by White.
Nothing is known of the stem, though the opinion may be hazarded that
Wardia is a member of the Medulloseae.
Adiantites bellidulus Heer and Lagenospermum Arberi Nathorst.
Reference is made to the genus Lagenospermum in the account of
Lagenostoma[459]. The species Lagenospermum Arberi has recently been
founded by Dr Nathorst[460] on some seeds obtained from Lower
Carboniferous rocks in Spitzbergen: a brief description is intercalated here
because it is probable that they were borne on fronds of the Adiantites type
similar to those on which White found the seeds described by him as
Wardia. The seeds of L. Arberi, 14–18 × 5 mm., are spindle-shaped with an
obtuse apex and longitudinally ribbed with a stalk at least 7 mm. long.
Nathorst considers that a cupule was probably present: the specimens do not
convey the impression of naked seeds and in some examples there are
indications of an investing envelope, though this may be the result of
tearing of the testa. Nathorst regards the Spitzbergen seeds as probably
specifically identical with a specimen described by Schmalhausen[461] from
Carboniferous rocks in the Urals as Rhabdocarpus orientalis Eich., a
species which agrees closely with Lagenospermum nitidulum as described
by Heer[462] (under the name Carpolithes nitidulus) and Nathorst[463] from
Spitzbergen. It is also possible that Kidston’s Rhabdocarpus elongatus[464],
from the Lanarkshire coal-field and elsewhere, recently transferred by
Arber[465] to Platyspermum, is an example of the same species. The chief
interest of Lagenospermum lies in the fact, assuming Nathorst’s correlation
of the seeds with Adiantites bellidulus Heer to be correct, that it is a typical
of the provisional term Aneimites. The seeds which occur at the apices of
slender pedicels on pinnae bearing relatively small pinnules with a reduced
lamina (fig. 445, B, C) are rhomboidal in shape, 4·5 mm. long and 2·5 mm.
broad. The bilaterally symmetrical seeds were probably enclosed, as White
suggests, in a fleshy integument which on pressure became laterally
extended as a wing-like border. In some of the seeds there is an indication
of a ‘slight collapse within the apex of the nutlet,’ which may mean the
presence of a pollen-chamber; but while the preservation is too imperfect to
afford any decisive evidence as to anatomical features, there is no reason to
doubt the conclusion as to the seed-nature of the organs described by White.
Nothing is known of the stem, though the opinion may be hazarded that
Wardia is a member of the Medulloseae.
Adiantites bellidulus Heer and Lagenospermum Arberi Nathorst.
Reference is made to the genus Lagenospermum in the account of
Lagenostoma[459]. The species Lagenospermum Arberi has recently been
founded by Dr Nathorst[460] on some seeds obtained from Lower
Carboniferous rocks in Spitzbergen: a brief description is intercalated here
because it is probable that they were borne on fronds of the Adiantites type
similar to those on which White found the seeds described by him as
Wardia. The seeds of L. Arberi, 14–18 × 5 mm., are spindle-shaped with an
obtuse apex and longitudinally ribbed with a stalk at least 7 mm. long.
Nathorst considers that a cupule was probably present: the specimens do not
convey the impression of naked seeds and in some examples there are
indications of an investing envelope, though this may be the result of
tearing of the testa. Nathorst regards the Spitzbergen seeds as probably
specifically identical with a specimen described by Schmalhausen[461] from
Carboniferous rocks in the Urals as Rhabdocarpus orientalis Eich., a
species which agrees closely with Lagenospermum nitidulum as described
by Heer[462] (under the name Carpolithes nitidulus) and Nathorst[463] from
Spitzbergen. It is also possible that Kidston’s Rhabdocarpus elongatus[464],
from the Lanarkshire coal-field and elsewhere, recently transferred by
Arber[465] to Platyspermum, is an example of the same species. The chief
interest of Lagenospermum lies in the fact, assuming Nathorst’s correlation
of the seeds with Adiantites bellidulus Heer to be correct, that it is a typical
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radiospermic seed, while Wardia, borne on foliage of the same general type,
is an equally typical platyspermic seed.
is an equally typical platyspermic seed.
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Page 215
CHAPTER XXXII.
CYCADOFILICES.
In this chapter are included several types represented by stems, but which
in the absence of definite information with regard to the reproductive
organs cannot be assigned to the Pteridosperms.
MEGALOXYLEAE.
Megaloxylon. Seward.
This genus is represented by a single species founded on a piece of stem
from the Lower Coal Measures of Lancashire discovered in the Binney
Collection in the Sedgwick Museum, Cambridge[466]. Nothing is known as
to the leaves, reproductive organs, or roots. The type-specimen consists
exclusively of primary and secondary xylem.
Megaloxylon Scotti Seward.
The type-specimen, reproduced natural size in fig. 446, A, B, consists of
a fragment of stem which at first sight bears a close resemblance to
Cordaites, but the apparent pith, 1·9 cm. in diameter, is the primary xylem
of the stele and is enclosed by an incomplete cylinder of secondary xylem 2
cm. broad. The distinction between the lighter primary xylem and the
darker secondary cylinder is especially well marked in the longitudinal
section (fig. 446, B). The central region, shown on a larger scale in fig. 447,
is occupied by groups of tracheids varying in size and shape associated with
thin-walled parenchyma: the latter is represented by lighter patches in the
section. The majority of the tracheids are characterised by their great
breadth—in some cases ·4 mm.—and their isodiametric or even
horizontally elongated and flattened form. Some of these large metaxylem
elements are seen in longitudinal section at m in fig. 448 where the
shrinkage and partial decay of the parenchymatous tissue have resulted in
the separation of transverse bands of xylem simulating the discoid pith of a
Cordaites. The walls of these tracheal cells are covered with multiseriate
pits. With the short and sometimes flattened xylem elements occur others of
CYCADOFILICES.
In this chapter are included several types represented by stems, but which
in the absence of definite information with regard to the reproductive
organs cannot be assigned to the Pteridosperms.
MEGALOXYLEAE.
Megaloxylon. Seward.
This genus is represented by a single species founded on a piece of stem
from the Lower Coal Measures of Lancashire discovered in the Binney
Collection in the Sedgwick Museum, Cambridge[466]. Nothing is known as
to the leaves, reproductive organs, or roots. The type-specimen consists
exclusively of primary and secondary xylem.
Megaloxylon Scotti Seward.
The type-specimen, reproduced natural size in fig. 446, A, B, consists of
a fragment of stem which at first sight bears a close resemblance to
Cordaites, but the apparent pith, 1·9 cm. in diameter, is the primary xylem
of the stele and is enclosed by an incomplete cylinder of secondary xylem 2
cm. broad. The distinction between the lighter primary xylem and the
darker secondary cylinder is especially well marked in the longitudinal
section (fig. 446, B). The central region, shown on a larger scale in fig. 447,
is occupied by groups of tracheids varying in size and shape associated with
thin-walled parenchyma: the latter is represented by lighter patches in the
section. The majority of the tracheids are characterised by their great
breadth—in some cases ·4 mm.—and their isodiametric or even
horizontally elongated and flattened form. Some of these large metaxylem
elements are seen in longitudinal section at m in fig. 448 where the
shrinkage and partial decay of the parenchymatous tissue have resulted in
the separation of transverse bands of xylem simulating the discoid pith of a
Cordaites. The walls of these tracheal cells are covered with multiseriate
pits. With the short and sometimes flattened xylem elements occur others of
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greater length, but these are chiefly met with in the more peripheral part of
the central region where some of the tracheids are much narrower and have
the form of ordinary water-conducting elements. On one side of the primary
xylem in fig. 447 an oval and more compact group of narrow and longer
tracheids is seen at lt1; this is a leaf-trace about to enter the secondary-
xylem cylinder on its outward course. The same leaf-trace is shown at lt in
fig. 446, B; as it descends the trace becomes less distinct and its elongated
elements gradually merge into the general mass of metaxylem. A portion of
this leaf-trace is seen in fig. 448, B, lt, close to the inner edge of the
secondary xylem, x2, and abutting internally on the contracted tissue, m,
which consists mainly of large and short tracheae with remains of
associated parenchyma. The trace includes some conjunctive parenchyma
interspersed with the tracheids: on its outer surface, that is on the abaxial
edge of the ovate xylem strand as shown at lt1 in fig. 447, there are six
external protoxylem strands. In the peripheral region of the primary xylem
of the section reproduced in fig. 447 there are several more or less well-
defined leaf-traces, e.g. lt2, lt3; these differ from that seen at lt1 in their
greater tangential breadth and in the less compact arrangement of the
tracheids. As each trace is followed downwards in the primary region of the
stele it tends to become broader, especially in a tangential direction; the
spiral protoxylem strands are more widely separated (fig. 448, A, px) and
the elongated and comparatively narrow tracheids as they spread out fan-
wise are reduced in length, finally passing over into the broad and short
reticulately pitted cells. Each leaf-trace can be followed through
approximately four internodes before its individuality is lost in the general
mass of metaxylem. The disposition of the peripheral traces is such as to
justify the conclusion that the phyllotaxis of the stem is ⅖.[467]
the central region where some of the tracheids are much narrower and have
the form of ordinary water-conducting elements. On one side of the primary
xylem in fig. 447 an oval and more compact group of narrow and longer
tracheids is seen at lt1; this is a leaf-trace about to enter the secondary-
xylem cylinder on its outward course. The same leaf-trace is shown at lt in
fig. 446, B; as it descends the trace becomes less distinct and its elongated
elements gradually merge into the general mass of metaxylem. A portion of
this leaf-trace is seen in fig. 448, B, lt, close to the inner edge of the
secondary xylem, x2, and abutting internally on the contracted tissue, m,
which consists mainly of large and short tracheae with remains of
associated parenchyma. The trace includes some conjunctive parenchyma
interspersed with the tracheids: on its outer surface, that is on the abaxial
edge of the ovate xylem strand as shown at lt1 in fig. 447, there are six
external protoxylem strands. In the peripheral region of the primary xylem
of the section reproduced in fig. 447 there are several more or less well-
defined leaf-traces, e.g. lt2, lt3; these differ from that seen at lt1 in their
greater tangential breadth and in the less compact arrangement of the
tracheids. As each trace is followed downwards in the primary region of the
stele it tends to become broader, especially in a tangential direction; the
spiral protoxylem strands are more widely separated (fig. 448, A, px) and
the elongated and comparatively narrow tracheids as they spread out fan-
wise are reduced in length, finally passing over into the broad and short
reticulately pitted cells. Each leaf-trace can be followed through
approximately four internodes before its individuality is lost in the general
mass of metaxylem. The disposition of the peripheral traces is such as to
justify the conclusion that the phyllotaxis of the stem is ⅖.[467]
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Fig. 446. Megaloxylon Scotti. A, B. Transverse and longitudinal sections.
x1, x2, primary and secondary xylem; lt, leaf-traces. Nat. size. C.
Secondary xylem.
x1, x2, primary and secondary xylem; lt, leaf-traces. Nat. size. C.
Secondary xylem.
Page 218
Fig. 447. Megaloxylon Scotti. Transverse section of the primary portion
of the stele with leaf-traces, lt, and the inner edge of the secondary
xylem.
of the stele with leaf-traces, lt, and the inner edge of the secondary
xylem.
Page 219
Fig. 448. Megaloxylon Scotti. A, transverse section at the junction of the
primary and secondary tissues; B, longitudinal section showing the
inner edge of the secondary xylem, x2, a leaf-trace, lt, and the
metaxylem, m.
The secondary xylem (fig. 446, C) resembles that of Lyginopteris and
Heterangium though it is less parenchymatous. The medullary rays are
numerous and vary in breadth from 1 to 5 cells, while the tracheids, with
multiseriate bordered pits on their radial walls, form bands 1 to 8 elements
primary and secondary tissues; B, longitudinal section showing the
inner edge of the secondary xylem, x2, a leaf-trace, lt, and the
metaxylem, m.
The secondary xylem (fig. 446, C) resembles that of Lyginopteris and
Heterangium though it is less parenchymatous. The medullary rays are
numerous and vary in breadth from 1 to 5 cells, while the tracheids, with
multiseriate bordered pits on their radial walls, form bands 1 to 8 elements
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in breadth. There are no regular rings of growth but occasional arcs of
narrow tracheids interfere slightly with the otherwise uniform structure of
the wood. A leaf-trace in its oblique outward course through the wood
becomes completely enclosed by a cylinder of secondary xylem and thus
appears to be concentric. Owing to the absence of any tissue external to the
secondary xylem of the stem, statements as to the subsequent behaviour of
the leaf-traces on emerging from the stele are purely hypothetical. It is,
however, not improbable that each concentric trace lost its secondary tissue
and broke up into several collateral strands, a suggestion based on the
behaviour of the leaf-traces in Medullosa anglica.
The most striking characteristics of Megaloxylon are: (i) the structure of
the primary xylem, particularly the unusual form of the majority of the
metaxylem tracheids, a form obviously correlated with storage rather than
with conduction of water; (ii) the gradual spreading of the leaf-traces and
their absorption as they descend into the main mass of the xylem; (iii) the
exarch structure of the primary xylem. Confining our attention to the
primary region of the stele; a comparison is at once suggested with
Heterangium. In Megaloxylon the peculiarities are the substitution of the
large storage-tracheids for the normal xylem-elements; the greater
irregularity in the groups of metaxylem; and an exarch instead of a mesarch
structure. In these last features the primary xylem agrees with that of recent
species of the Schizaeaceous Fern Lygodium and the external protoxylem is
a character shared with Rhetinangium. The occurrence of short tracheids
similar to those of Megaloxylon in the inner portion of the stele of the
Osmundaceous Fern Zalesskya gracilis (Eich.)[468] may be quoted as an
example of parallel modification but, as Scott[469] points out, the
resemblance has no phylogenetic significance. The secondary xylem though
less parenchymatous than in recent Cycads agrees more closely with the
manoxylic than with the pycnoxylic type.
Megaloxylon affords an interesting example of a combination of primary
stelar anatomical features, comparable in the exarch position of the
protoxylem with the stele of Lygodium, and secondary wood similar to that
of Lyginopteris and Heterangium. The large metaxylem tracheids may be
regarded as derivatives of elements which in some ancestral type were
structurally fitted for the rôle of water-transport and made up the xylem of a
Lygodium-like stele with little or no secondary xylem. As the cambial
narrow tracheids interfere slightly with the otherwise uniform structure of
the wood. A leaf-trace in its oblique outward course through the wood
becomes completely enclosed by a cylinder of secondary xylem and thus
appears to be concentric. Owing to the absence of any tissue external to the
secondary xylem of the stem, statements as to the subsequent behaviour of
the leaf-traces on emerging from the stele are purely hypothetical. It is,
however, not improbable that each concentric trace lost its secondary tissue
and broke up into several collateral strands, a suggestion based on the
behaviour of the leaf-traces in Medullosa anglica.
The most striking characteristics of Megaloxylon are: (i) the structure of
the primary xylem, particularly the unusual form of the majority of the
metaxylem tracheids, a form obviously correlated with storage rather than
with conduction of water; (ii) the gradual spreading of the leaf-traces and
their absorption as they descend into the main mass of the xylem; (iii) the
exarch structure of the primary xylem. Confining our attention to the
primary region of the stele; a comparison is at once suggested with
Heterangium. In Megaloxylon the peculiarities are the substitution of the
large storage-tracheids for the normal xylem-elements; the greater
irregularity in the groups of metaxylem; and an exarch instead of a mesarch
structure. In these last features the primary xylem agrees with that of recent
species of the Schizaeaceous Fern Lygodium and the external protoxylem is
a character shared with Rhetinangium. The occurrence of short tracheids
similar to those of Megaloxylon in the inner portion of the stele of the
Osmundaceous Fern Zalesskya gracilis (Eich.)[468] may be quoted as an
example of parallel modification but, as Scott[469] points out, the
resemblance has no phylogenetic significance. The secondary xylem though
less parenchymatous than in recent Cycads agrees more closely with the
manoxylic than with the pycnoxylic type.
Megaloxylon affords an interesting example of a combination of primary
stelar anatomical features, comparable in the exarch position of the
protoxylem with the stele of Lygodium, and secondary wood similar to that
of Lyginopteris and Heterangium. The large metaxylem tracheids may be
regarded as derivatives of elements which in some ancestral type were
structurally fitted for the rôle of water-transport and made up the xylem of a
Lygodium-like stele with little or no secondary xylem. As the cambial
Page 221
activity increased and centrifugal xylem became a prominent feature,
usurping the function of the centripetal xylem, the latter became modified
and fitted for a new service.
RHETINANGIEAE.
Rhetinangium. Gordon.
Rhetinangium Arberi Gordon.
The stem on which this genus is founded was discovered by Dr
Gordon[470] in the Calciferous Sandstone series of Pettycur: a specimen
collected by Dr Kidston in Berwickshire may be specifically identical with
the Pettycur plant. We know nothing of the leaves or reproductive organs of
Rhetinangium. The stem, approximately 2 cm. in diameter, was probably
cylindrical; it possesses a single stele consisting mainly of a central primary
region occupied by anastomosing groups of tracheids, 130–150μ in
diameter, embedded in parenchyma containing numerous secretory sacs and
ducts. In the peripheral region of the stele the groups of tracheids consist of
narrower elements characterised by exarch protoxylem. Each peripheral
group forms the base of a wedge of secondary xylem (fig. 450, x2), the
primary medullary rays being in direct connexion with some of the
parenchyma of the primary xylem. The secondary tracheids, 45–85μ in
diameter, have multiseriate bordered pits on their radial walls and the rays
are broad and deep as in Heterangium and Lyginopteris. With the exception
of the external position of the protoxylem, the stele of Rhetinangium is
practically identical with that of Heterangium, though in Rhetinangium the
primary tracheids form larger and fewer groups. The inner cortex is
composed of thin-walled cells with many secretory sacs: there are no
stereome elements. In the outer cortex (fig. 449, cr) radially disposed bands
of stereome form a reticulum with narrow and very long meshes like that of
Medullosan petioles.
The recently recorded occurrence of polydesmic petioles[471] in
Heterangium is of special interest from the point of view of the comparison
of that genus with Rhetinangium and the Medulloseae.
The very broad decurrent petiole-bases are a striking feature, the major
diameter of the pulvinus-like base of the leaf-stalk exceeding that of the
usurping the function of the centripetal xylem, the latter became modified
and fitted for a new service.
RHETINANGIEAE.
Rhetinangium. Gordon.
Rhetinangium Arberi Gordon.
The stem on which this genus is founded was discovered by Dr
Gordon[470] in the Calciferous Sandstone series of Pettycur: a specimen
collected by Dr Kidston in Berwickshire may be specifically identical with
the Pettycur plant. We know nothing of the leaves or reproductive organs of
Rhetinangium. The stem, approximately 2 cm. in diameter, was probably
cylindrical; it possesses a single stele consisting mainly of a central primary
region occupied by anastomosing groups of tracheids, 130–150μ in
diameter, embedded in parenchyma containing numerous secretory sacs and
ducts. In the peripheral region of the stele the groups of tracheids consist of
narrower elements characterised by exarch protoxylem. Each peripheral
group forms the base of a wedge of secondary xylem (fig. 450, x2), the
primary medullary rays being in direct connexion with some of the
parenchyma of the primary xylem. The secondary tracheids, 45–85μ in
diameter, have multiseriate bordered pits on their radial walls and the rays
are broad and deep as in Heterangium and Lyginopteris. With the exception
of the external position of the protoxylem, the stele of Rhetinangium is
practically identical with that of Heterangium, though in Rhetinangium the
primary tracheids form larger and fewer groups. The inner cortex is
composed of thin-walled cells with many secretory sacs: there are no
stereome elements. In the outer cortex (fig. 449, cr) radially disposed bands
of stereome form a reticulum with narrow and very long meshes like that of
Medullosan petioles.
The recently recorded occurrence of polydesmic petioles[471] in
Heterangium is of special interest from the point of view of the comparison
of that genus with Rhetinangium and the Medulloseae.
The very broad decurrent petiole-bases are a striking feature, the major
diameter of the pulvinus-like base of the leaf-stalk exceeding that of the
Page 222
stem (fig. 449, p). Several xylem-strands from the peripheral region of the
primary xylem go to form a single leaf-trace: these [** symbol U]-shaped
strands of xylem destined for a leaf are connected laterally by parenchyma
and form an irregularly corrugated band. Fig. 450 shows a petiole-trace still
enclosed on each side by the secondary xylem cylinder x2.
Fig. 449. Rhetinangium Arberi Gord. Transverse section of stem with
large leaf-base; cr, outer cortex of stem; p, petiole. (After Gordon;
× 1¾.)
There are several protoxylem groups in a leaf-trace, one on the outer face
of each xylem-strand. In the petiole the xylem groups are more intimately
connected and the trace has the form of a flat band with abaxial protoxylem.
There is no indication that a leaf-trace undergoes division into separate
strands. The roots are described as tetrarch with well-developed secondary
xylem.
Fig. 450. Transverse section of leaf-trace of Rhetinangium Arberi
showing the exarch structure; x2, secondary xylem. (After Gordon.)
The primary xylem of Rhetinangium agrees in its exarch structure with
the Palaeozoic genera Sutcliffia, Megaloxylon and Stenomyelon, also with
Lygodium and some other recent Ferns: the secondary wood is of the
manoxylic type like that of Lyginopteris, Heterangium and other genera. In
primary xylem go to form a single leaf-trace: these [** symbol U]-shaped
strands of xylem destined for a leaf are connected laterally by parenchyma
and form an irregularly corrugated band. Fig. 450 shows a petiole-trace still
enclosed on each side by the secondary xylem cylinder x2.
Fig. 449. Rhetinangium Arberi Gord. Transverse section of stem with
large leaf-base; cr, outer cortex of stem; p, petiole. (After Gordon;
× 1¾.)
There are several protoxylem groups in a leaf-trace, one on the outer face
of each xylem-strand. In the petiole the xylem groups are more intimately
connected and the trace has the form of a flat band with abaxial protoxylem.
There is no indication that a leaf-trace undergoes division into separate
strands. The roots are described as tetrarch with well-developed secondary
xylem.
Fig. 450. Transverse section of leaf-trace of Rhetinangium Arberi
showing the exarch structure; x2, secondary xylem. (After Gordon.)
The primary xylem of Rhetinangium agrees in its exarch structure with
the Palaeozoic genera Sutcliffia, Megaloxylon and Stenomyelon, also with
Lygodium and some other recent Ferns: the secondary wood is of the
manoxylic type like that of Lyginopteris, Heterangium and other genera. In
Page 223
the general structure of the stele Rhetinangium agrees with Sutcliffia and,
except in the exarch structure of the primary xylem, with the steles of
Heterangium and Medullosa anglica[472]; but the structure and origin of the
leaf-traces are characters which mark it off from Sutcliffia. The
sclerenchymatous bands in the inner cortex of Heterangium are
unrepresented in Rhetinangium, and in the latter genus the abundance of
secretory sacs and ducts is a characteristic feature, moreover in
Rhetinangium, the leaf-trace consists of several groups of primary xylem-
elements. Dr Gordon regards Megaloxylon as the type which comes nearest
to Rhetinangium; but the differences in the structure of the secondary wood
and the marked contrast between the leaf-traces are too pronounced to
justify a preference for Megaloxylon over Heterangium in the order of
affinity. Gordon considers that the undivided leaf-trace of Rhetinangium
may represent a form transitional between the simple leaf-trace of
Lyginopteris and the much divided type in Medullosa. The external position
of the protoxylem is a character to which too much weight may easily be
attached: the difference in position between the protoxylem of
Rhetinangium and Heterangium is in some examples of the latter genus
hardly perceptible. Kubart[473] speaks of the stele of his species Heterangium
Sturi as being almost exarch. The inconstancy in the position of the
protoxylem in the xylem of Osmundaceous stems and in the primary
bundles of Eristophyton and other Palaeozoic genera is worthy of
consideration in this connexion.
Fig. 451. Stenomyelon tuedianum Kidst. Transverse section of stem. The
black patches represent leaf-traces. (After Kidston; × 1½.)
STENOMYELEAE.
Stenomyelon. Kidston.
Stenomyelon tuedianum Kidston. The specimens on which this
monotypic genus is founded[474] were obtained from the Lower
except in the exarch structure of the primary xylem, with the steles of
Heterangium and Medullosa anglica[472]; but the structure and origin of the
leaf-traces are characters which mark it off from Sutcliffia. The
sclerenchymatous bands in the inner cortex of Heterangium are
unrepresented in Rhetinangium, and in the latter genus the abundance of
secretory sacs and ducts is a characteristic feature, moreover in
Rhetinangium, the leaf-trace consists of several groups of primary xylem-
elements. Dr Gordon regards Megaloxylon as the type which comes nearest
to Rhetinangium; but the differences in the structure of the secondary wood
and the marked contrast between the leaf-traces are too pronounced to
justify a preference for Megaloxylon over Heterangium in the order of
affinity. Gordon considers that the undivided leaf-trace of Rhetinangium
may represent a form transitional between the simple leaf-trace of
Lyginopteris and the much divided type in Medullosa. The external position
of the protoxylem is a character to which too much weight may easily be
attached: the difference in position between the protoxylem of
Rhetinangium and Heterangium is in some examples of the latter genus
hardly perceptible. Kubart[473] speaks of the stele of his species Heterangium
Sturi as being almost exarch. The inconstancy in the position of the
protoxylem in the xylem of Osmundaceous stems and in the primary
bundles of Eristophyton and other Palaeozoic genera is worthy of
consideration in this connexion.
Fig. 451. Stenomyelon tuedianum Kidst. Transverse section of stem. The
black patches represent leaf-traces. (After Kidston; × 1½.)
STENOMYELEAE.
Stenomyelon. Kidston.
Stenomyelon tuedianum Kidston. The specimens on which this
monotypic genus is founded[474] were obtained from the Lower
Page 224
Carboniferous rocks (Calciferous Sandstone series) at Norham Bridge,
Berwickshire, Scotland. They consist of petrified pieces of a flattened stem,
a fragment of a rachis and portions of laminae: there is no evidence as to the
nature of the reproductive organs. The original form of the stem is obscured
by the destruction of a considerable part of the cortex and the consequent
flattening of the whole with the production of wing-like extensions of the
imperfectly preserved tissues enclosing the almost cylindrical stele (figs.
451, 452).
The stele consists of a bluntly triangular core of primary xylem, 3–4 mm.
in diameter, composed almost entirely of reticulately pitted tracheids
reaching a diameter of 160μ: a few parenchymatous cells occur in the
peripheral region and a band of parenchyma extends from the middle of
each of the three sides of the xylem to the centre of the stele, thus dividing
the primary conducting tissue into three groups which are the expression of
a phyllotaxis of ⅓. The tracheids near the outer face of each xylem-group
are narrower than the others and have scalariform pitting. The secondary
xylem first appears along the slightly concave sides of the primary stele,
eventually enclosing the whole: it consists of tracheids with multiseriate
pits on the radial walls and numerous deep medullary rays 1–6 cells broad.
No phloem is preserved though it is probable that a narrow band was
originally present. A characteristic feature is afforded by a zone of thick-
walled cells, regarded as periderm, encircling the stele and formed by a
deep-seated phellogen. On the outer face of this band there are projecting
bosses, and similar sclerous nests are scattered in the cortex. The outer
cortex has a Sparganum[475] type of hypoderm, that is long vertical strands
of fibres alternating with parenchyma. The leaf-traces are formed from the
blunt angles of the primary xylem; an angle becomes nipped off as a more
or less cylindrical strand enclosed by a zone of secondary tracheids which is
very narrow on the adaxial side (fig. 452). Protoxylem was recognised only
in the leaf-traces and not in the rest of the stele. A pair of protoxylem
strands occurs on the outer edge of a prominent angle of xylem before it
becomes detached from the stele, and these form a single strand at a lower
level. As a leaf-trace passes outwards, the exarch xylem strand becomes
mesarch and there is a single protoxylem group except at a point near the
bifurcation of a trace. In its passage through the cortex a leaf-trace divides
repeatedly, the secondary xylem on the outer face of each strand being
retained for a considerable time.
Berwickshire, Scotland. They consist of petrified pieces of a flattened stem,
a fragment of a rachis and portions of laminae: there is no evidence as to the
nature of the reproductive organs. The original form of the stem is obscured
by the destruction of a considerable part of the cortex and the consequent
flattening of the whole with the production of wing-like extensions of the
imperfectly preserved tissues enclosing the almost cylindrical stele (figs.
451, 452).
The stele consists of a bluntly triangular core of primary xylem, 3–4 mm.
in diameter, composed almost entirely of reticulately pitted tracheids
reaching a diameter of 160μ: a few parenchymatous cells occur in the
peripheral region and a band of parenchyma extends from the middle of
each of the three sides of the xylem to the centre of the stele, thus dividing
the primary conducting tissue into three groups which are the expression of
a phyllotaxis of ⅓. The tracheids near the outer face of each xylem-group
are narrower than the others and have scalariform pitting. The secondary
xylem first appears along the slightly concave sides of the primary stele,
eventually enclosing the whole: it consists of tracheids with multiseriate
pits on the radial walls and numerous deep medullary rays 1–6 cells broad.
No phloem is preserved though it is probable that a narrow band was
originally present. A characteristic feature is afforded by a zone of thick-
walled cells, regarded as periderm, encircling the stele and formed by a
deep-seated phellogen. On the outer face of this band there are projecting
bosses, and similar sclerous nests are scattered in the cortex. The outer
cortex has a Sparganum[475] type of hypoderm, that is long vertical strands
of fibres alternating with parenchyma. The leaf-traces are formed from the
blunt angles of the primary xylem; an angle becomes nipped off as a more
or less cylindrical strand enclosed by a zone of secondary tracheids which is
very narrow on the adaxial side (fig. 452). Protoxylem was recognised only
in the leaf-traces and not in the rest of the stele. A pair of protoxylem
strands occurs on the outer edge of a prominent angle of xylem before it
becomes detached from the stele, and these form a single strand at a lower
level. As a leaf-trace passes outwards, the exarch xylem strand becomes
mesarch and there is a single protoxylem group except at a point near the
bifurcation of a trace. In its passage through the cortex a leaf-trace divides
repeatedly, the secondary xylem on the outer face of each strand being
retained for a considerable time.
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Our meagre knowledge of the nature of the leaves is based on incomplete
fragments found in association with the stem. The leaf is believed to have
been simple and characterised by a thick lamina with a hypodermal zone of
sclerous strands and several vascular bundles.
Fig. 452. Stenomyelon tuedianum. Transverse section of stele. (After
Kidston; × 7.)
As Kidston and Gwynne-Vaughan[476] remark, Stenomyelon is a very
distinct type; while resembling Sutcliffia in some respects it differs from
that genus not only in the structure of the primary stele but in the absence of
the system of meristeles which form so characteristic a feature of the latter
genus.
CYCADOXYLEAE.
Cycadoxylon. Renault.
This generic term[477] is applied to a few types of Permian and Upper
Carboniferous stems possessing a vascular cylinder, which may reach a
considerable breadth, of secondary centrifugally developed xylem and
phloem enclosing a large pith containing either a narrow, peripherally
fragments found in association with the stem. The leaf is believed to have
been simple and characterised by a thick lamina with a hypodermal zone of
sclerous strands and several vascular bundles.
Fig. 452. Stenomyelon tuedianum. Transverse section of stele. (After
Kidston; × 7.)
As Kidston and Gwynne-Vaughan[476] remark, Stenomyelon is a very
distinct type; while resembling Sutcliffia in some respects it differs from
that genus not only in the structure of the primary stele but in the absence of
the system of meristeles which form so characteristic a feature of the latter
genus.
CYCADOXYLEAE.
Cycadoxylon. Renault.
This generic term[477] is applied to a few types of Permian and Upper
Carboniferous stems possessing a vascular cylinder, which may reach a
considerable breadth, of secondary centrifugally developed xylem and
phloem enclosing a large pith containing either a narrow, peripherally
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placed, and more or less continuous cylinder of inversely orientated
conducting tissue or scattered bands of centripetal xylem and phloem. The
secondary xylem is manoxylic, while the internal vascular tissue recalls that
of Ptychoxylon and to a less extent the inverted arcs that are rarely met with
in Lyginopteris stems. A brief diagnosis of two species may serve to
illustrate the genus: a third species is included in Cycadoxylon, but it is
founded on material too incomplete to admit of satisfactory diagnosis.
Cycadoxylon Fremyi Renault.
This Permian species[478] is represented by a piece of stem 2–2·5 cm. in
diameter (fig. 453, B) characterised by (i) a fairly broad parenchymatous
cortex with secretory canals and several hypodermal nests of sclerous
tissue, (ii) a cylinder of secondary xylem and phloem nearly the whole of
which is centrifugal, (iii) a large pith containing several scattered narrower
bands or arcs of centripetally developed xylem and phloem. The tracheids,
with 4–6 series of hexagonal pits, form radially disposed rows, 1–4
elements broad, separated by broad and deep medullary rays. Renault does
not mention the occurrence of any primary xylem as distinct from the
secondary centrifugal xylem, but in a section which I examined some years
ago in his laboratory there appeared to be a group of primary tracheids.
There are no anastomoses between the main cylinder and the internal bands
of inversely orientated tissue.
Cycadoxylon robustum (Seward).
This species[479] is based on a piece of stem from the Lower Coal
Measures of Lancashire first described by Williamson and identified as an
unusually large example of Lyginopteris. Williamson and Scott, while
recognising certain features in addition to the large size of the stem, which
must have reached 14 cm. in diameter, expressed the view that ‘there is a
presumption that it really belonged to a Lyginodendron, or to some plant of
the same type of structure.’ The examination of additional material led me
to adopt the name Lyginodendron robustum, though I suggested that
possibly Cycadoxylon might be the more appropriate genus. Subsequently
Scott[480] proposed the substitution of Cycadoxylon for Lyginodendron.
The type-specimen consists of secondary xylem agreeing closely in
structure with Lyginopteris and recent Cycads: the pith, 2·9 cm. in breadth,
conducting tissue or scattered bands of centripetal xylem and phloem. The
secondary xylem is manoxylic, while the internal vascular tissue recalls that
of Ptychoxylon and to a less extent the inverted arcs that are rarely met with
in Lyginopteris stems. A brief diagnosis of two species may serve to
illustrate the genus: a third species is included in Cycadoxylon, but it is
founded on material too incomplete to admit of satisfactory diagnosis.
Cycadoxylon Fremyi Renault.
This Permian species[478] is represented by a piece of stem 2–2·5 cm. in
diameter (fig. 453, B) characterised by (i) a fairly broad parenchymatous
cortex with secretory canals and several hypodermal nests of sclerous
tissue, (ii) a cylinder of secondary xylem and phloem nearly the whole of
which is centrifugal, (iii) a large pith containing several scattered narrower
bands or arcs of centripetally developed xylem and phloem. The tracheids,
with 4–6 series of hexagonal pits, form radially disposed rows, 1–4
elements broad, separated by broad and deep medullary rays. Renault does
not mention the occurrence of any primary xylem as distinct from the
secondary centrifugal xylem, but in a section which I examined some years
ago in his laboratory there appeared to be a group of primary tracheids.
There are no anastomoses between the main cylinder and the internal bands
of inversely orientated tissue.
Cycadoxylon robustum (Seward).
This species[479] is based on a piece of stem from the Lower Coal
Measures of Lancashire first described by Williamson and identified as an
unusually large example of Lyginopteris. Williamson and Scott, while
recognising certain features in addition to the large size of the stem, which
must have reached 14 cm. in diameter, expressed the view that ‘there is a
presumption that it really belonged to a Lyginodendron, or to some plant of
the same type of structure.’ The examination of additional material led me
to adopt the name Lyginodendron robustum, though I suggested that
possibly Cycadoxylon might be the more appropriate genus. Subsequently
Scott[480] proposed the substitution of Cycadoxylon for Lyginodendron.
The type-specimen consists of secondary xylem agreeing closely in
structure with Lyginopteris and recent Cycads: the pith, 2·9 cm. in breadth,
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is incompletely preserved; there is a narrow band of centripetal xylem[481] at
the periphery of the perimedullary region and close to the inner face of the
main mass of wood (fig. 453, C; the black line marks the position of the
centripetal xylem). Nests of sclerous tissue and secretory canals are
scattered in the medullary parenchyma and deeper in this region are arcs of
secondary parenchyma, possibly periderm. In places the centripetal and
centrifugal xylem are in contact and occasionally the tapered ends of the
rows of centrifugal tracheids merge into groups of primary xylem elements.
The preservation in the central region is far from complete, and although
the occurrence of primary xylem groups is probable it cannot be said to be
positively established. At the inner edge of the centrifugal xylem and in
tangential longitudinal sections a few leaf-traces are seen, but nothing is
known as to the nature of the leaf-traces in their course beyond the stele nor
have we any data with regard to the leaves or reproductive organs.
This older species differs from Cycadoxylon Fremyi in the limitation of
the centripetal xylem to the outer portion of the pith and in the presence of
sclerous nests in the medullary region, though the latter character is
probably of no great taxonomic value. Cycadoxylon robustum approaches
more closely to Lyginopteris, and although the differences are sufficient to
justify a distinctive generic name, there can be little doubt as to a fairly
intimate relationship between this type of Cycadoxylon and Lyginopteris.
Ptychoxylon. Renault.
Ptychoxylon[482] Levyi Renault. Like many Palaeozoic genera founded on
anatomical features, Ptychoxylon[483] is represented only by stems, our
knowledge of the leaves being confined to the leaf-traces in the stem which
appears to have a phyllotaxis of ⅜. The stem of this Permian species has a
diameter of 5–6 cm.: the comparatively broad cortex contains numerous
secretory canals, but in place of hypodermal strands of stereome there is a
superficial periderm. The vascular tissue, consisting of secondary xylem
and phloem, assumes different patterns at different levels. There is an outer
vascular cylinder of centrifugally developed xylem and phloem; the xylem
is manoxylic and the tracheids have 3–5 rows of bordered pits on the radial
walls. At intervals the continuity of the main stele is broken by the
formation of leaf-gaps and before one gap is repaired a second may be
produced, thus converting the cylinder into two crescentic and infolded
bands (fig. 453, A). A striking character is the occurrence in the large
the periphery of the perimedullary region and close to the inner face of the
main mass of wood (fig. 453, C; the black line marks the position of the
centripetal xylem). Nests of sclerous tissue and secretory canals are
scattered in the medullary parenchyma and deeper in this region are arcs of
secondary parenchyma, possibly periderm. In places the centripetal and
centrifugal xylem are in contact and occasionally the tapered ends of the
rows of centrifugal tracheids merge into groups of primary xylem elements.
The preservation in the central region is far from complete, and although
the occurrence of primary xylem groups is probable it cannot be said to be
positively established. At the inner edge of the centrifugal xylem and in
tangential longitudinal sections a few leaf-traces are seen, but nothing is
known as to the nature of the leaf-traces in their course beyond the stele nor
have we any data with regard to the leaves or reproductive organs.
This older species differs from Cycadoxylon Fremyi in the limitation of
the centripetal xylem to the outer portion of the pith and in the presence of
sclerous nests in the medullary region, though the latter character is
probably of no great taxonomic value. Cycadoxylon robustum approaches
more closely to Lyginopteris, and although the differences are sufficient to
justify a distinctive generic name, there can be little doubt as to a fairly
intimate relationship between this type of Cycadoxylon and Lyginopteris.
Ptychoxylon. Renault.
Ptychoxylon[482] Levyi Renault. Like many Palaeozoic genera founded on
anatomical features, Ptychoxylon[483] is represented only by stems, our
knowledge of the leaves being confined to the leaf-traces in the stem which
appears to have a phyllotaxis of ⅜. The stem of this Permian species has a
diameter of 5–6 cm.: the comparatively broad cortex contains numerous
secretory canals, but in place of hypodermal strands of stereome there is a
superficial periderm. The vascular tissue, consisting of secondary xylem
and phloem, assumes different patterns at different levels. There is an outer
vascular cylinder of centrifugally developed xylem and phloem; the xylem
is manoxylic and the tracheids have 3–5 rows of bordered pits on the radial
walls. At intervals the continuity of the main stele is broken by the
formation of leaf-gaps and before one gap is repaired a second may be
produced, thus converting the cylinder into two crescentic and infolded
bands (fig. 453, A). A striking character is the occurrence in the large
Page 228
parenchymatous central region of internal vascular bands or arcs varying in
size and number at different levels and composed of centripetally developed
secondary xylem and phloem. These internal bands differ from the outer
and broader cylinder both in their inverse orientation and their limited
vertical range. The connexion between the inner and outer vascular tissue
and the alteration in plan of the conducting tissue at different levels are
illustrated by fig. 453, 1–4, simplified from some of Renault’s figures of
successive sections through a vertical distance of 4–5 cm. In section 1 the
main cylinder is continuous except for a small gap where a leaf-trace is
about to be given off: there are three internal vascular bands similar in
structure to the outer stele but inversely orientated. At a higher level
(section 2) the leaf-gap is larger and in it is a double leaf-trace of two
collateral strands consisting of primary centripetal xylem and a fan-like
group of secondary xylem and phloem. The free edges of the outer stele of
section 1 have curved inwards and united with the two lateral medullary
bands, while the lower internal band of section 1 has increased in extent and
forms a discontinuous arc with the upper portions enclosed by the loops
formed by the infolded ends of the outer vascular tissue. In section 3 a
second leaf-gap has been formed in the outer stele and its invaginated ends
have fused with the internal bands. In section 4 the first leaf-gap is closed
and the invaginated bands of section 3 have broken up into an irregular
circle of shorter bands. The section reproduced in fig. 453, A, shows the
main cylinder in the form of two curved and flattened loops, each composed
partly of the centrifugally developed xylem and phloem of the main stele
and in part of the inversely orientated tissue of the inner bands. At a lower
level the two bands b, b, will become detached as the upper leaf-gap is
closed and form part of an inner cylinder like the discontinuous ellipse
formed by the two bands c. The section of a branch-stele is seen at a.
size and number at different levels and composed of centripetally developed
secondary xylem and phloem. These internal bands differ from the outer
and broader cylinder both in their inverse orientation and their limited
vertical range. The connexion between the inner and outer vascular tissue
and the alteration in plan of the conducting tissue at different levels are
illustrated by fig. 453, 1–4, simplified from some of Renault’s figures of
successive sections through a vertical distance of 4–5 cm. In section 1 the
main cylinder is continuous except for a small gap where a leaf-trace is
about to be given off: there are three internal vascular bands similar in
structure to the outer stele but inversely orientated. At a higher level
(section 2) the leaf-gap is larger and in it is a double leaf-trace of two
collateral strands consisting of primary centripetal xylem and a fan-like
group of secondary xylem and phloem. The free edges of the outer stele of
section 1 have curved inwards and united with the two lateral medullary
bands, while the lower internal band of section 1 has increased in extent and
forms a discontinuous arc with the upper portions enclosed by the loops
formed by the infolded ends of the outer vascular tissue. In section 3 a
second leaf-gap has been formed in the outer stele and its invaginated ends
have fused with the internal bands. In section 4 the first leaf-gap is closed
and the invaginated bands of section 3 have broken up into an irregular
circle of shorter bands. The section reproduced in fig. 453, A, shows the
main cylinder in the form of two curved and flattened loops, each composed
partly of the centrifugally developed xylem and phloem of the main stele
and in part of the inversely orientated tissue of the inner bands. At a lower
level the two bands b, b, will become detached as the upper leaf-gap is
closed and form part of an inner cylinder like the discontinuous ellipse
formed by the two bands c. The section of a branch-stele is seen at a.
Page 229
Fig. 453.
A. Ptychoxylon Levyi; transverse section of stem; a, stele of branch.
(After Renault.)
B. Cycadoxylon Fremyi; transverse section of stem. (After Renault.)
C. Cycadoxylon robustum; centre of stem.
1–4, diagrams of sections of the stem of Ptychoxylon at different levels.
(Simplified from Renault.)
Ptychoxylon differs considerably from Medullosa, which Renault
included in the Cycadoxyleae, in the plan of the vascular system: there is
nothing corresponding to the ‘partial pith’ or primary region which forms
the central portion of the plate- and snake-rings in Medullosa. The double
leaf-trace and the absence of the Medullosa type of hypoderm are other
distinguishing features. The paired leaf-bundles suggest comparison with
Lyginopteris among other genera and, as Scott[484] points out, the internal
arcs of inversely orientated tissue which sometimes occur in the peripheral
region of the pith of Lyginopteris (fig. 405, C, c) behave like the internal
bands of Ptychoxylon in occasionally joining the main cylinder at a leaf-
gap; but the differences outweigh the resemblances. As regards the general
A. Ptychoxylon Levyi; transverse section of stem; a, stele of branch.
(After Renault.)
B. Cycadoxylon Fremyi; transverse section of stem. (After Renault.)
C. Cycadoxylon robustum; centre of stem.
1–4, diagrams of sections of the stem of Ptychoxylon at different levels.
(Simplified from Renault.)
Ptychoxylon differs considerably from Medullosa, which Renault
included in the Cycadoxyleae, in the plan of the vascular system: there is
nothing corresponding to the ‘partial pith’ or primary region which forms
the central portion of the plate- and snake-rings in Medullosa. The double
leaf-trace and the absence of the Medullosa type of hypoderm are other
distinguishing features. The paired leaf-bundles suggest comparison with
Lyginopteris among other genera and, as Scott[484] points out, the internal
arcs of inversely orientated tissue which sometimes occur in the peripheral
region of the pith of Lyginopteris (fig. 405, C, c) behave like the internal
bands of Ptychoxylon in occasionally joining the main cylinder at a leaf-
gap; but the differences outweigh the resemblances. As regards the general
Page 230
arrangement of the vascular tissue in two irregular concentric circles and
their connexions with one another, but not in the structure of the xylem and
phloem, there is a similarity between this genus and such a Fern as
Matonia. In the varying patterns formed by the vascular system at different
levels in the stem Ptychoxylon resembles the Ferns Polypodium
quercifolium and P. heracleum[485].
CALAMOPITYEAE.
Calamopitys. Unger.
In 1856 Unger[486] described several fragmentary petrifactions from
Thuringian strata of Upper Devonian age, the majority of which he referred
to the Calamarieae and the Rhachiopterideae. In an earlier publication[487] he
gave a list of species including two families, the Haplocalameae and the
Calamoxyleae, assigned by him to the group Calamarieae: in the
Haplocalameae he placed the new genera Kalymma, Calamosyrix,
Calamopteris, and Haplocalamus. These were subsequently examined by
Graf Solms-Laubach and identified as portions of petioles, for the most part
belonging to unknown stems. In his second family, the Calamoxyleae,
Unger included the single genus Calamopitys represented by the type-
species C. Saturni. The type-specimens have been thoroughly investigated
by Solms-Laubach[488] who instituted the family-name Calamopityeae and
recognised a close anatomical affinity between Calamopitys and
Lyginopteris, a conclusion which led to the incorporation of Unger’s genus
in the Pteridosperms. Further data have been supplied by Zalessky[489] and,
more recently, by Scott and Jeffrey[490] who have recognised Calamopitys in
Lower Carboniferous beds in Kentucky.
Calamopitys Saturni Unger.
Our knowledge of this and other species is confined to stems and
petioles. One of the largest examples of the species is a piece of stem with a
diameter of 1·5 cm.: the single stele consists of a parenchymatous pith
enclosed by secondary xylem made up of tracheids with 4–8 rows of
bordered pits and medullary rays more than one cell broad and of
considerable depth. Between the inner edge of the wood and the pith are
groups of primary xylem (fig. 454, B, x) which, like those in Lyginopteris,
constitute the leaf-traces: each has a single internal protoxylem strand (fig.
their connexions with one another, but not in the structure of the xylem and
phloem, there is a similarity between this genus and such a Fern as
Matonia. In the varying patterns formed by the vascular system at different
levels in the stem Ptychoxylon resembles the Ferns Polypodium
quercifolium and P. heracleum[485].
CALAMOPITYEAE.
Calamopitys. Unger.
In 1856 Unger[486] described several fragmentary petrifactions from
Thuringian strata of Upper Devonian age, the majority of which he referred
to the Calamarieae and the Rhachiopterideae. In an earlier publication[487] he
gave a list of species including two families, the Haplocalameae and the
Calamoxyleae, assigned by him to the group Calamarieae: in the
Haplocalameae he placed the new genera Kalymma, Calamosyrix,
Calamopteris, and Haplocalamus. These were subsequently examined by
Graf Solms-Laubach and identified as portions of petioles, for the most part
belonging to unknown stems. In his second family, the Calamoxyleae,
Unger included the single genus Calamopitys represented by the type-
species C. Saturni. The type-specimens have been thoroughly investigated
by Solms-Laubach[488] who instituted the family-name Calamopityeae and
recognised a close anatomical affinity between Calamopitys and
Lyginopteris, a conclusion which led to the incorporation of Unger’s genus
in the Pteridosperms. Further data have been supplied by Zalessky[489] and,
more recently, by Scott and Jeffrey[490] who have recognised Calamopitys in
Lower Carboniferous beds in Kentucky.
Calamopitys Saturni Unger.
Our knowledge of this and other species is confined to stems and
petioles. One of the largest examples of the species is a piece of stem with a
diameter of 1·5 cm.: the single stele consists of a parenchymatous pith
enclosed by secondary xylem made up of tracheids with 4–8 rows of
bordered pits and medullary rays more than one cell broad and of
considerable depth. Between the inner edge of the wood and the pith are
groups of primary xylem (fig. 454, B, x) which, like those in Lyginopteris,
constitute the leaf-traces: each has a single internal protoxylem strand (fig.
Page 231
455, B). The comparatively wide cortex consists of parenchyma with a
hypoderm of the Sparganum type. Each primary xylem-strand passes out as
a single leaf-trace through the secondary xylem and on emerging divides
into two as in Lyginopteris: these branch in the cortex and the two are
replaced by six in the leaf-base (fig. 454, B–D). As seen in figs. 454, C,
455, A, the boundary between the stem proper and the decurrent leaf-base is
marked by a line of stereome strands. The petioles of Calamopitys Saturni
agree generally in structure with the imperfect specimens on which Unger
founded his genus Kalymma[491], so named in reference to the structure of
the hypodermal zone. A specimen described by Solms-Laubach as a
Kalymma petiole occurs in organic connexion with a stem of Calamopitys
(fig. 454, C: a detached petiole is shown in fig. 454, D). The identification
by White[492] of this attached petiole with Unger’s K. grandis has been
confirmed by Scott and Jeffrey. A fuller account of Kalymma (fig. 456) is
given on a later page, as the petioles so named belong to more than one
species of stem.
Fig. 454. Calamopitys Saturni. B, stem with leaf-base; x, primary xylem
and pith; black patches represent leaf-traces; C, stem with two
leaf-bases; D, section of petiole. (After Solms-Laubach.)
hypoderm of the Sparganum type. Each primary xylem-strand passes out as
a single leaf-trace through the secondary xylem and on emerging divides
into two as in Lyginopteris: these branch in the cortex and the two are
replaced by six in the leaf-base (fig. 454, B–D). As seen in figs. 454, C,
455, A, the boundary between the stem proper and the decurrent leaf-base is
marked by a line of stereome strands. The petioles of Calamopitys Saturni
agree generally in structure with the imperfect specimens on which Unger
founded his genus Kalymma[491], so named in reference to the structure of
the hypodermal zone. A specimen described by Solms-Laubach as a
Kalymma petiole occurs in organic connexion with a stem of Calamopitys
(fig. 454, C: a detached petiole is shown in fig. 454, D). The identification
by White[492] of this attached petiole with Unger’s K. grandis has been
confirmed by Scott and Jeffrey. A fuller account of Kalymma (fig. 456) is
given on a later page, as the petioles so named belong to more than one
species of stem.
Fig. 454. Calamopitys Saturni. B, stem with leaf-base; x, primary xylem
and pith; black patches represent leaf-traces; C, stem with two
leaf-bases; D, section of petiole. (After Solms-Laubach.)
Page 232
Fig. 455. Calamopitys Saturni. A, stem with leaf-bases; × 5. B, stele
showing leaf-trace after emerging from the secondary xylem; × 16.
(After Zalessky.)
In Calamopitys Saturni we have a plant agreeing with Lyginopteris in the
possession of secondary xylem of the manoxylic type and in the structure of
the common primary bundles, while it is distinguished from Lyginopteris by
the greater number and by the structure of the bundles in the axis of the
leaf.
Calamopitys annularis (Unger)[493].
This species, originally assigned to the genus Stigmaria, has a more
strongly developed primary vascular system and there is a more decided
tendency towards the formation of a continuous zone of primary xylem on
the inner edge of the secondary wood; but where the protoxylem tracheids
occur the metaxylem elements form definite strands, like those of C.
Saturni. It has been pointed out by Scott and Jeffrey that there is some
showing leaf-trace after emerging from the secondary xylem; × 16.
(After Zalessky.)
In Calamopitys Saturni we have a plant agreeing with Lyginopteris in the
possession of secondary xylem of the manoxylic type and in the structure of
the common primary bundles, while it is distinguished from Lyginopteris by
the greater number and by the structure of the bundles in the axis of the
leaf.
Calamopitys annularis (Unger)[493].
This species, originally assigned to the genus Stigmaria, has a more
strongly developed primary vascular system and there is a more decided
tendency towards the formation of a continuous zone of primary xylem on
the inner edge of the secondary wood; but where the protoxylem tracheids
occur the metaxylem elements form definite strands, like those of C.
Saturni. It has been pointed out by Scott and Jeffrey that there is some
Page 233
evidence of the occurrence of tracheids in the parenchymatous pith of this
species, an important feature distinguishing it from C. Saturni and
connecting it with C. americana. Information with regard to the behaviour
of the leaf-traces is far from complete, but there are indications that each
trace divides into two before emerging from the secondary xylem[494]. The
leaf-traces in the cortex are concentric as in C. Saturni.
Calamopitys americana Scott and Jeffrey.
This Lower Carboniferous species[495] from the Waverley shales of
Kentucky is represented by portions of stems and leaf-bases and detached
petioles. The secondary wood consists of tracheids, 30–60μ in diameter,
with deep and broad rays; the small pits on the tracheids form 5–6
alternating series. Phloem and cambium are very imperfectly preserved.
The outer cortex is of the same type as in other species. At the inner edge of
the secondary xylem there is a ring of primary xylem strands of mesarch
structure composed of rather larger tracheids, 80–120μ in diameter,
separated from one another by narrow strips of parenchyma. So far the
vascular tissue agrees with that of C. annularis. In the American species the
axial region is not a parenchymatous pith but a protostele, consisting of
parenchyma and a larger or smaller number of tracheal groups, the number
being less in stems with a larger central region. The peripheral strands alone
are concerned with the emission of leaf-traces, as in Heterangium. Each
primary xylem strand divides into two as it leaves the perimedullary zone
and passes through the secondary xylem as two bundles, each being
accompanied by an arc of secondary tracheids which, in the cortical region,
completely surrounds the primary elements. At a later stage the single
protoxylem of each trace divides into two and before entering the leaf-base
there is a further division. In some specimens leaf-bases of the Kalymma
type were found attached to the stem. The occurrence of tracheids in the
axial region is a distinguishing feature and suggests a comparison with
Heterangium, while C. Saturni agrees more closely with Lyginopteris; the
species C. annularis would appear, from the recent observations of Scott
and Jeffrey, to occupy an intermediate position.
Calamopitys, as the generic designation is here employed, is confined to
central Germany and Kentucky and occurs in Upper Devonian and Lower
Carboniferous strata. There is, however, some doubt as to the exact
species, an important feature distinguishing it from C. Saturni and
connecting it with C. americana. Information with regard to the behaviour
of the leaf-traces is far from complete, but there are indications that each
trace divides into two before emerging from the secondary xylem[494]. The
leaf-traces in the cortex are concentric as in C. Saturni.
Calamopitys americana Scott and Jeffrey.
This Lower Carboniferous species[495] from the Waverley shales of
Kentucky is represented by portions of stems and leaf-bases and detached
petioles. The secondary wood consists of tracheids, 30–60μ in diameter,
with deep and broad rays; the small pits on the tracheids form 5–6
alternating series. Phloem and cambium are very imperfectly preserved.
The outer cortex is of the same type as in other species. At the inner edge of
the secondary xylem there is a ring of primary xylem strands of mesarch
structure composed of rather larger tracheids, 80–120μ in diameter,
separated from one another by narrow strips of parenchyma. So far the
vascular tissue agrees with that of C. annularis. In the American species the
axial region is not a parenchymatous pith but a protostele, consisting of
parenchyma and a larger or smaller number of tracheal groups, the number
being less in stems with a larger central region. The peripheral strands alone
are concerned with the emission of leaf-traces, as in Heterangium. Each
primary xylem strand divides into two as it leaves the perimedullary zone
and passes through the secondary xylem as two bundles, each being
accompanied by an arc of secondary tracheids which, in the cortical region,
completely surrounds the primary elements. At a later stage the single
protoxylem of each trace divides into two and before entering the leaf-base
there is a further division. In some specimens leaf-bases of the Kalymma
type were found attached to the stem. The occurrence of tracheids in the
axial region is a distinguishing feature and suggests a comparison with
Heterangium, while C. Saturni agrees more closely with Lyginopteris; the
species C. annularis would appear, from the recent observations of Scott
and Jeffrey, to occupy an intermediate position.
Calamopitys, as the generic designation is here employed, is confined to
central Germany and Kentucky and occurs in Upper Devonian and Lower
Carboniferous strata. There is, however, some doubt as to the exact
Page 234
geological horizon of the rocks in both countries though in neither case is
there any question of an horizon higher than Lower Carboniferous. Certain
specimens from the Lower Carboniferous of Scotland described by Scott[496]
as species of Calamopitys have been made by Zalessky the type of a new
genus, Eristophyton, and are dealt with under that name.
Kalymma. Unger.
Kalymma grandis (petiole of Calamopitys). Under the generic name
Kalymma Unger described specimens from Thuringia of Upper Devonian
age which he assigned to two species, K. grandis and K. striatum. Solms-
Laubach has shown that Kalymma is not an independent stem as Unger
believed but a petiole of Calamopitys, and this has been confirmed by Scott
and Jeffrey who found a leaf-base with the Kalymma type of structure in
connexion with a piece of Calamopitys stem, probably C. americana. An
examination of a section (2·3 cm. broad) of Unger’s K. grandis in the
collection of the Geological Survey enables me to confirm the conclusions
recently published by Scott and Jeffrey. The best specimens of Kalymma,
which appear to be identical in essential features with Unger’s type-species,
are from Kentucky, some from the Genessee shales of Upper Devonian age
and others from beds (Waverley shales) believed to be Lower
Carboniferous. Through the kindness of Prof. Bower I have had an
opportunity of examining sections from the older horizon in his possession.
The transverse section reproduced in fig. 456 has a diameter of 3·8 × 2·2
cm.[497]: on one side the radially placed plates of stereome are clearly shown,
and in the outer portion of the ground-tissue is a ring of vascular bundles
varying in size and shape but with a general tendency to a radially
elongated form. The ground-tissue consists of homogeneous parenchyma:
in one place I noticed what appeared to be a large secretory canal, but
secretory tissue, generally at least, is unrepresented. The xylem is composed
of imperfectly preserved elements, which appear to have scalariform pits;
spiral protoxylem strands, embedded in the metaxylem as two or four
groups, occur near the ends of the long axis of the bundle and in some cases
also near the centre. The phloem probably surrounded the xylem, though it
is not certain whether the arrangement was collateral or concentric: there
are no secondary-xylem tracheids, though in some places I noticed a
tendency to a radial disposition of cells at the periphery of the vascular
tissue simulating an early stage of secondary growth. Unger’s second
there any question of an horizon higher than Lower Carboniferous. Certain
specimens from the Lower Carboniferous of Scotland described by Scott[496]
as species of Calamopitys have been made by Zalessky the type of a new
genus, Eristophyton, and are dealt with under that name.
Kalymma. Unger.
Kalymma grandis (petiole of Calamopitys). Under the generic name
Kalymma Unger described specimens from Thuringia of Upper Devonian
age which he assigned to two species, K. grandis and K. striatum. Solms-
Laubach has shown that Kalymma is not an independent stem as Unger
believed but a petiole of Calamopitys, and this has been confirmed by Scott
and Jeffrey who found a leaf-base with the Kalymma type of structure in
connexion with a piece of Calamopitys stem, probably C. americana. An
examination of a section (2·3 cm. broad) of Unger’s K. grandis in the
collection of the Geological Survey enables me to confirm the conclusions
recently published by Scott and Jeffrey. The best specimens of Kalymma,
which appear to be identical in essential features with Unger’s type-species,
are from Kentucky, some from the Genessee shales of Upper Devonian age
and others from beds (Waverley shales) believed to be Lower
Carboniferous. Through the kindness of Prof. Bower I have had an
opportunity of examining sections from the older horizon in his possession.
The transverse section reproduced in fig. 456 has a diameter of 3·8 × 2·2
cm.[497]: on one side the radially placed plates of stereome are clearly shown,
and in the outer portion of the ground-tissue is a ring of vascular bundles
varying in size and shape but with a general tendency to a radially
elongated form. The ground-tissue consists of homogeneous parenchyma:
in one place I noticed what appeared to be a large secretory canal, but
secretory tissue, generally at least, is unrepresented. The xylem is composed
of imperfectly preserved elements, which appear to have scalariform pits;
spiral protoxylem strands, embedded in the metaxylem as two or four
groups, occur near the ends of the long axis of the bundle and in some cases
also near the centre. The phloem probably surrounded the xylem, though it
is not certain whether the arrangement was collateral or concentric: there
are no secondary-xylem tracheids, though in some places I noticed a
tendency to a radial disposition of cells at the periphery of the vascular
tissue simulating an early stage of secondary growth. Unger’s second
Page 235
species Kalymma striata is characterised by an arrangement of the bundles
similar to that in a petiole described by Scott and Jeffrey as Calamopteris
Hippocrepis which differs from Kalymma in the partial substitution of
bands of vascular tissue for separate bundles and to some extent in the
disposition of the bundles. The two types of petiole Kalymma and
Calamopteris, as Scott and Jeffrey state, are very closely allied. Dawson
and Penhallow[498] have also described Kalymma grandis from Kentucky but
they, like Unger, mistook the hypodermal stereome for an outer zone of
vascular bundles. The petioles from Germany and North America included
under the name Kalymma grandis, though too similar to be referred to
different species, no doubt represent petioles of stems which are
unquestionably distinct types: as in the case of Myeloxylon in its relation to
the genus Medullosa, Kalymma stands for several closely allied forms of
petioles belonging to several species of Calamopitys.
Fig. 456. Kalymma grandis. (From a section in the possession of Prof.
Bower; × 4.)
Eristophyton. Zalessky.
Eristophyton fasciculare (Scott). The generic name Eristophyton[499] was
proposed by Zalessky[500] for two incomplete stems of Lower Carboniferous
similar to that in a petiole described by Scott and Jeffrey as Calamopteris
Hippocrepis which differs from Kalymma in the partial substitution of
bands of vascular tissue for separate bundles and to some extent in the
disposition of the bundles. The two types of petiole Kalymma and
Calamopteris, as Scott and Jeffrey state, are very closely allied. Dawson
and Penhallow[498] have also described Kalymma grandis from Kentucky but
they, like Unger, mistook the hypodermal stereome for an outer zone of
vascular bundles. The petioles from Germany and North America included
under the name Kalymma grandis, though too similar to be referred to
different species, no doubt represent petioles of stems which are
unquestionably distinct types: as in the case of Myeloxylon in its relation to
the genus Medullosa, Kalymma stands for several closely allied forms of
petioles belonging to several species of Calamopitys.
Fig. 456. Kalymma grandis. (From a section in the possession of Prof.
Bower; × 4.)
Eristophyton. Zalessky.
Eristophyton fasciculare (Scott). The generic name Eristophyton[499] was
proposed by Zalessky[500] for two incomplete stems of Lower Carboniferous
Page 236
age provisionally[501] referred by Scott to Araucarioxylon and subsequently
to Calamopitys[502]. The species E. fasciculare was founded on material
obtained by Dr Kidston from the Lower Carboniferous of Dumbarton,
Scotland, and on a specimen in the Williamson collection from
Northumberland. There is a small pith of parenchyma, 2–3 mm. in diameter,
with eight strands of primary xylem of varying diameter (fig. 457) and in
each a single protoxylem-group. The primary xylem elements are
considerably larger than the secondary tracheids. These xylem-bundles are
leaf-traces and their disposition points to a phyllotaxis of ⅖ . The traces
attain their maximum size when about to pass out through the secondary
xylem. The tracheids are reticulate and scalariform while some have an
intermediate type of pitting. A leaf-trace on reaching the pith gradually
moves further from the xylem-cylinder and may be separated from it by 2–6
layers of parenchyma: as it passes down the pith the protoxylem strand
assumes an almost endarch position consequent on the reduction of the
centripetal xylem. In Scott’s words, ‘each circummedullary strand branches
at regular intervals; the one branch, that on the anodic side [turned towards
the course of the genetic spiral], becomes the leaf-trace and passes out,
while the other continues its course up the stem as a reparatory strand, until
the next leaf of the orthostichy has to be supplied[503].’ The secondary xylem
consists almost entirely of tracheids with 3–4 rows of pits on the radial
walls and medullary rays usually one cell broad varying in depth from 1 or
2 to 16 or more cells. A characteristic feature of the secondary xylem is the
occurrence on its inner face of numerous short and broad tracheae similar to
the still larger tracheae in the primary stele of Megaloxylon[504]. Nothing is
known as to the behaviour of the leaf-trace in the extrastelar region, but the
fact that an outgoing trace was found to have two protoxylems points to a
subdivision similar to that of the foliar bundles of Calamopitys Saturni. A
well-marked difference between Eristophyton fasciculare and Calamopitys
and Lyginopteris is the more compact structure of the secondary wood; it is
pycnoxylic and not manoxylic. Prof. Zalessky in criticising the use of the
generic title Calamopitys puts forward several arguments in support of his
institution of a new designation: (i) the primary xylem strands of
Eristophyton are not confined to the periphery of the pith as is the case in
Calamopitys Saturni, though he speaks of one leaf-trace in the latter species
separated by several layers of cells from the xylem-cylinder; (ii) some of
the pith-cells have thick walls and dark contents in distinction to the
to Calamopitys[502]. The species E. fasciculare was founded on material
obtained by Dr Kidston from the Lower Carboniferous of Dumbarton,
Scotland, and on a specimen in the Williamson collection from
Northumberland. There is a small pith of parenchyma, 2–3 mm. in diameter,
with eight strands of primary xylem of varying diameter (fig. 457) and in
each a single protoxylem-group. The primary xylem elements are
considerably larger than the secondary tracheids. These xylem-bundles are
leaf-traces and their disposition points to a phyllotaxis of ⅖ . The traces
attain their maximum size when about to pass out through the secondary
xylem. The tracheids are reticulate and scalariform while some have an
intermediate type of pitting. A leaf-trace on reaching the pith gradually
moves further from the xylem-cylinder and may be separated from it by 2–6
layers of parenchyma: as it passes down the pith the protoxylem strand
assumes an almost endarch position consequent on the reduction of the
centripetal xylem. In Scott’s words, ‘each circummedullary strand branches
at regular intervals; the one branch, that on the anodic side [turned towards
the course of the genetic spiral], becomes the leaf-trace and passes out,
while the other continues its course up the stem as a reparatory strand, until
the next leaf of the orthostichy has to be supplied[503].’ The secondary xylem
consists almost entirely of tracheids with 3–4 rows of pits on the radial
walls and medullary rays usually one cell broad varying in depth from 1 or
2 to 16 or more cells. A characteristic feature of the secondary xylem is the
occurrence on its inner face of numerous short and broad tracheae similar to
the still larger tracheae in the primary stele of Megaloxylon[504]. Nothing is
known as to the behaviour of the leaf-trace in the extrastelar region, but the
fact that an outgoing trace was found to have two protoxylems points to a
subdivision similar to that of the foliar bundles of Calamopitys Saturni. A
well-marked difference between Eristophyton fasciculare and Calamopitys
and Lyginopteris is the more compact structure of the secondary wood; it is
pycnoxylic and not manoxylic. Prof. Zalessky in criticising the use of the
generic title Calamopitys puts forward several arguments in support of his
institution of a new designation: (i) the primary xylem strands of
Eristophyton are not confined to the periphery of the pith as is the case in
Calamopitys Saturni, though he speaks of one leaf-trace in the latter species
separated by several layers of cells from the xylem-cylinder; (ii) some of
the pith-cells have thick walls and dark contents in distinction to the
Page 237
homogeneous parenchyma of Calamopitys, a feature of little importance;
(iii) the difference in the structure of the secondary wood already alluded to,
though this loses some of its significance by the occurrence of narrower
rays, more like those of Eristophyton, in C. annularis; (iv) the more
elliptical and broader pits in the secondary tracheids in place of the more
regular hexagonal form in Calamopitys. While admitting a certain degree of
relationship between the two types, Zalessky asserts that as yet we have
insufficient evidence to justify their generic union. Scott[505] maintains that
Zalessky does not attach sufficient weight to the form and mesarch structure
of the primary xylem bundles as a feature common to both genera.
Fig. 457. Eristophyton fasciculare. Transverse section showing the
relation of primary (black) to secondary xylem. (After Scott.)
Eristophyton Beinertianum (Goeppert).
1850. Araucarites Beinertianus Goeppert, Mon. Foss. Conif. p. 233, Pls.
42, 43.
1872. Araucarioxylon Beinertianum Kraus, in Schimper’s Trait. Pal. Vol.
ii. p. 381.
1888. Araucarites Beinertianus Goeppert and Stenzel, Abh. K. Preuss.
Akad. Wiss. p. 30, Pl. iv.
1902. Calamopitys Beinertiana Scott, Trans. R. Soc. Edinb. Vol. 40, p.
341, Pls. i., iv., v.
(iii) the difference in the structure of the secondary wood already alluded to,
though this loses some of its significance by the occurrence of narrower
rays, more like those of Eristophyton, in C. annularis; (iv) the more
elliptical and broader pits in the secondary tracheids in place of the more
regular hexagonal form in Calamopitys. While admitting a certain degree of
relationship between the two types, Zalessky asserts that as yet we have
insufficient evidence to justify their generic union. Scott[505] maintains that
Zalessky does not attach sufficient weight to the form and mesarch structure
of the primary xylem bundles as a feature common to both genera.
Fig. 457. Eristophyton fasciculare. Transverse section showing the
relation of primary (black) to secondary xylem. (After Scott.)
Eristophyton Beinertianum (Goeppert).
1850. Araucarites Beinertianus Goeppert, Mon. Foss. Conif. p. 233, Pls.
42, 43.
1872. Araucarioxylon Beinertianum Kraus, in Schimper’s Trait. Pal. Vol.
ii. p. 381.
1888. Araucarites Beinertianus Goeppert and Stenzel, Abh. K. Preuss.
Akad. Wiss. p. 30, Pl. iv.
1902. Calamopitys Beinertiana Scott, Trans. R. Soc. Edinb. Vol. 40, p.
341, Pls. i., iv., v.
Page 238
1909[506]
Ullmannites
. Beinertianus Tuzson, Result. Wiss. Erforsch.
Balatonsees, Bd i. Teil i. p. 24.
1911. Eristophyton Beinertianum Zalessky, Com. Geol. St Pétersb. p. 24.
The pith, 13–15 mm. in diameter, is rather larger than in E. fasciculare
and is characterised by the occurrence of dark sclerotic nests surrounded by
radially disposed rows of parenchyma. The primary xylem strands are more
numerous and smaller than in E. fasciculare and these increase in diameter
as they approach the secondary wood. In places the primary xylem elements
form a more or less continuous band as in Calamopitys annularis. The
largest leaf-trace bundles at the periphery of the pith are mesarch (fig. 458),
but as each trace passes down the pith the reduction in the centripetal xylem
is carried further than in E. fasciculare until the xylem-strand becomes
endarch in the lower part of its course. The secondary tracheids have
usually two contiguous rows of pits and the medullary rays are one cell
broad.
Fig. 458. Eristophyton Beinertianum. A strand of primary xylem,
showing the protoxylem, px, abutting on the secondary xylem. (×
35. After Zalessky.)
There can be no doubt as to the generic identity of the two species
referred to Eristophyton, but the question as to the degree of affinity to
Calamopitys is more difficult to settle. There is force in Zalessky’s
contention that these two stems should not be retained in Calamopitys: the
recently described American species, C. americana Scott and Jeffrey, gives
emphasis to the view that the restriction of Calamopitys to the German (and
Ullmannites
. Beinertianus Tuzson, Result. Wiss. Erforsch.
Balatonsees, Bd i. Teil i. p. 24.
1911. Eristophyton Beinertianum Zalessky, Com. Geol. St Pétersb. p. 24.
The pith, 13–15 mm. in diameter, is rather larger than in E. fasciculare
and is characterised by the occurrence of dark sclerotic nests surrounded by
radially disposed rows of parenchyma. The primary xylem strands are more
numerous and smaller than in E. fasciculare and these increase in diameter
as they approach the secondary wood. In places the primary xylem elements
form a more or less continuous band as in Calamopitys annularis. The
largest leaf-trace bundles at the periphery of the pith are mesarch (fig. 458),
but as each trace passes down the pith the reduction in the centripetal xylem
is carried further than in E. fasciculare until the xylem-strand becomes
endarch in the lower part of its course. The secondary tracheids have
usually two contiguous rows of pits and the medullary rays are one cell
broad.
Fig. 458. Eristophyton Beinertianum. A strand of primary xylem,
showing the protoxylem, px, abutting on the secondary xylem. (×
35. After Zalessky.)
There can be no doubt as to the generic identity of the two species
referred to Eristophyton, but the question as to the degree of affinity to
Calamopitys is more difficult to settle. There is force in Zalessky’s
contention that these two stems should not be retained in Calamopitys: the
recently described American species, C. americana Scott and Jeffrey, gives
emphasis to the view that the restriction of Calamopitys to the German (and
Page 239
American) types is the safer course. While Calamopitys as thus restricted is
almost certainly a Pteridosperm, the inclusion of the types referred to
Eristophyton in the same category rests on a more slender basis.
CLADOXYLEAE.
This order was founded by Unger[507] for some imperfectly preserved
stems from Palaeozoic strata in Thuringia and in it he included the two
genera Cladoxylon and Schizoxylon. There is some doubt as to the precise
age of the Thuringian beds; they were assigned by Richter to the Devonian
system and subsequently placed in the Culm: Solms-Laubach in his later
reference to Unger’s plants favours a Devonian horizon[508]. Unger included
the Cladoxyleae in the Lycopodiales, and though this conclusion is not
accepted the position of the order is still uncertain. His genus Schizoxylon
has no claim to generic separation from Cladoxylon. An inspection of the
illustrations in the memoir by Richter and Unger reveals a striking
resemblance in the main anatomical features between several types assigned
to different genera and distributed among the Cladoxyleae and
Rhachiopterideae (a term first used by Corda for petrified rachises or
petioles of ferns) and other orders. Solms-Laubach[509], to whom our more
accurate information as to Unger’s plants is chiefly due, is inclined to
regard the specimens referred by Unger to the genus Arctopodium as young
stems of Cladoxylon, and he draws attention to a close similarity between
Hierogramma, another of Unger’s genera, and Cladoxylon. Paul
Bertrand[510] goes further in considering that the following genera represent
one generic type, namely Syncardia (fig. 459, F), Hierogramma,
Arctopodium, Cladoxylon, and Schizoxylon. The same author interprets the
fossils so named by Unger as stems and does not agree with the inclusion of
any of them in the Rhachiopterideae. Without losing sight of the fact that
Bertrand’s conclusion is not based on proof but is the expression of a view
suggested by a close agreement in general anatomical plan, I venture to
adopt the designation Cladoxylon in a wide sense primarily on the ground
that Bertrand’s view is probably correct and in part for the sake of
convenience of description. As Unger’s species of Cladoxylon differ from
one another in features which may fairly be regarded as of minor
importance, they are included under one specific name.
Cladoxylon. Unger.
almost certainly a Pteridosperm, the inclusion of the types referred to
Eristophyton in the same category rests on a more slender basis.
CLADOXYLEAE.
This order was founded by Unger[507] for some imperfectly preserved
stems from Palaeozoic strata in Thuringia and in it he included the two
genera Cladoxylon and Schizoxylon. There is some doubt as to the precise
age of the Thuringian beds; they were assigned by Richter to the Devonian
system and subsequently placed in the Culm: Solms-Laubach in his later
reference to Unger’s plants favours a Devonian horizon[508]. Unger included
the Cladoxyleae in the Lycopodiales, and though this conclusion is not
accepted the position of the order is still uncertain. His genus Schizoxylon
has no claim to generic separation from Cladoxylon. An inspection of the
illustrations in the memoir by Richter and Unger reveals a striking
resemblance in the main anatomical features between several types assigned
to different genera and distributed among the Cladoxyleae and
Rhachiopterideae (a term first used by Corda for petrified rachises or
petioles of ferns) and other orders. Solms-Laubach[509], to whom our more
accurate information as to Unger’s plants is chiefly due, is inclined to
regard the specimens referred by Unger to the genus Arctopodium as young
stems of Cladoxylon, and he draws attention to a close similarity between
Hierogramma, another of Unger’s genera, and Cladoxylon. Paul
Bertrand[510] goes further in considering that the following genera represent
one generic type, namely Syncardia (fig. 459, F), Hierogramma,
Arctopodium, Cladoxylon, and Schizoxylon. The same author interprets the
fossils so named by Unger as stems and does not agree with the inclusion of
any of them in the Rhachiopterideae. Without losing sight of the fact that
Bertrand’s conclusion is not based on proof but is the expression of a view
suggested by a close agreement in general anatomical plan, I venture to
adopt the designation Cladoxylon in a wide sense primarily on the ground
that Bertrand’s view is probably correct and in part for the sake of
convenience of description. As Unger’s species of Cladoxylon differ from
one another in features which may fairly be regarded as of minor
importance, they are included under one specific name.
Cladoxylon. Unger.
Page 240
Cladoxylon mirabile Unger[511]. The following are regarded as
specifically identical with or closely allied to Cladoxylon mirabile: C.
dubium, Schizoxylon taeniatum, Hierogramma mysticum, Syncardia pusilla,
Arctopodium insigne and A. radiatum[512].
i. Stems. The stems assigned to Cladoxylon are characterised by a
complex system of steles, either simple or branched and occasionally
anastomosing, presenting in transverse section the form of oval or
cylindrical strands or narrow, straight or curved bands arranged on a more
or less clearly marked radial plan (fig. 459, A, B, D). In some stems the
primary vascular tissue is enclosed by secondary xylem and phloem (fig.
460, B), while in others (Unger’s Arctopodium, Hierogramma[513],
Syncardia) there is no evidence of secondary thickening. The diagrammatic
drawing represented in fig. 459, F, shows a section of a small axis, regarded
by Unger and Solms as a petiole (3 mm. in diameter), containing four
vascular strands composed exclusively of primary xylem, each with one or,
in the case of a double strand, two protoxylem groups. This type may be a
slender stem or branch or possibly a petiole. The other extreme, as regards
complexity of vascular structure, is represented by such stems as those
shown in fig. 459, A, B, D. In Unger’s Cladoxylon mirabile (fig. 459, A;
fig. 460, B) the stem reaches a diameter of 3 cm. and consists of several
radially disposed plates of vascular tissue with an occasional smaller oval or
cylindrical stele embedded in a ground-tissue composed of thick-walled
cells. The plates are curved like a U or sinuous and not infrequently
anastomosing. In a section of this type figured by Unger the vascular plates
appear to form a complex anastomosing system, but Solms[514] states that the
drawing exaggerates the amount of fusion between the strands, and an
examination of a section in the collection of the English Geological Survey
cut from Unger’s specimen enables me to confirm this statement. Each
vascular plate consists of a narrow median region composed of primary
tracheids with a scalariform type of pitting surrounded by secondary
tracheids with interspersed medullary rays one cell broad. The thickness of
the secondary xylem varies considerably in the same specimen and in
places this tissue is hardly represented, a fact of importance in view of the
very striking resemblance between Arctopodium and Cladoxylon, the
sections referred by Unger to the former genus having steles without any
secondary xylem. The occurrence of one or two elongated spaces (shown in
black in fig. 459, A) near the distal end of each plate mark the position of
specifically identical with or closely allied to Cladoxylon mirabile: C.
dubium, Schizoxylon taeniatum, Hierogramma mysticum, Syncardia pusilla,
Arctopodium insigne and A. radiatum[512].
i. Stems. The stems assigned to Cladoxylon are characterised by a
complex system of steles, either simple or branched and occasionally
anastomosing, presenting in transverse section the form of oval or
cylindrical strands or narrow, straight or curved bands arranged on a more
or less clearly marked radial plan (fig. 459, A, B, D). In some stems the
primary vascular tissue is enclosed by secondary xylem and phloem (fig.
460, B), while in others (Unger’s Arctopodium, Hierogramma[513],
Syncardia) there is no evidence of secondary thickening. The diagrammatic
drawing represented in fig. 459, F, shows a section of a small axis, regarded
by Unger and Solms as a petiole (3 mm. in diameter), containing four
vascular strands composed exclusively of primary xylem, each with one or,
in the case of a double strand, two protoxylem groups. This type may be a
slender stem or branch or possibly a petiole. The other extreme, as regards
complexity of vascular structure, is represented by such stems as those
shown in fig. 459, A, B, D. In Unger’s Cladoxylon mirabile (fig. 459, A;
fig. 460, B) the stem reaches a diameter of 3 cm. and consists of several
radially disposed plates of vascular tissue with an occasional smaller oval or
cylindrical stele embedded in a ground-tissue composed of thick-walled
cells. The plates are curved like a U or sinuous and not infrequently
anastomosing. In a section of this type figured by Unger the vascular plates
appear to form a complex anastomosing system, but Solms[514] states that the
drawing exaggerates the amount of fusion between the strands, and an
examination of a section in the collection of the English Geological Survey
cut from Unger’s specimen enables me to confirm this statement. Each
vascular plate consists of a narrow median region composed of primary
tracheids with a scalariform type of pitting surrounded by secondary
tracheids with interspersed medullary rays one cell broad. The thickness of
the secondary xylem varies considerably in the same specimen and in
places this tissue is hardly represented, a fact of importance in view of the
very striking resemblance between Arctopodium and Cladoxylon, the
sections referred by Unger to the former genus having steles without any
secondary xylem. The occurrence of one or two elongated spaces (shown in
black in fig. 459, A) near the distal end of each plate mark the position of
Page 241
the protoxylem tracheids. Fig. 459, C, represents a stele of a stem referred
by Unger and by Solms to Cladoxylon dubium which shows the typical
Cladoxylon structure, namely the central primary xylem with distally placed
protoxylem and the enclosing sheath of secondary xylem. In the stem
shown in fig. 459, D (C. dubium) there are 12 steles, each constructed on
the plan already described, differing in their relatively broader and shorter
form and in the greater breadth of the secondary xylem from those seen in
fig. 459, A (C. mirabile). The black areas in fig. 459, A, show the primary
xylem, and the protoxylem is seen in fig. 459, C. A stem described by
Dawson[515] as Asteropteris noveboracensis from Devonian beds is
compared by him with Unger’s Cladoxylon mirabile and regarded as
possibly allied to it. The radial plates of xylem in Dawson’s plant meet in
the centre like those of Asterochlaena and the leaf-traces are of the
Clepsydropsoid type.
by Unger and by Solms to Cladoxylon dubium which shows the typical
Cladoxylon structure, namely the central primary xylem with distally placed
protoxylem and the enclosing sheath of secondary xylem. In the stem
shown in fig. 459, D (C. dubium) there are 12 steles, each constructed on
the plan already described, differing in their relatively broader and shorter
form and in the greater breadth of the secondary xylem from those seen in
fig. 459, A (C. mirabile). The black areas in fig. 459, A, show the primary
xylem, and the protoxylem is seen in fig. 459, C. A stem described by
Dawson[515] as Asteropteris noveboracensis from Devonian beds is
compared by him with Unger’s Cladoxylon mirabile and regarded as
possibly allied to it. The radial plates of xylem in Dawson’s plant meet in
the centre like those of Asterochlaena and the leaf-traces are of the
Clepsydropsoid type.
Page 242
Fig. 459. A, Cladoxylon mirabile, section of stem; B, Cladoxylon
taeniatum, section of stem; C, Cladoxylon dubium, section of stele;
D, C. dubium, section of stem; E, Cladoxylon (?) mirabile, section of
petiole; F, Syncardia pusilla; G, development of leaf-trace in
Cladoxylon taeniatum. (A–E, after Solms-Laubach; F, after Unger;
G. after P. Bertrand.)
The type of stem for which Unger founded his genus Schizoxylon is
represented in fig. 459, B; there are five small steles in the centre and
external to these eleven radially arranged plates, with oval steles between
them, in the peripheral region of the stem. Each stele consists of primary
(black in the figure) and secondary xylem and agrees with the steles in the
other stems.
taeniatum, section of stem; C, Cladoxylon dubium, section of stele;
D, C. dubium, section of stem; E, Cladoxylon (?) mirabile, section of
petiole; F, Syncardia pusilla; G, development of leaf-trace in
Cladoxylon taeniatum. (A–E, after Solms-Laubach; F, after Unger;
G. after P. Bertrand.)
The type of stem for which Unger founded his genus Schizoxylon is
represented in fig. 459, B; there are five small steles in the centre and
external to these eleven radially arranged plates, with oval steles between
them, in the peripheral region of the stem. Each stele consists of primary
(black in the figure) and secondary xylem and agrees with the steles in the
other stems.
Page 243
From the type of stem illustrated by Cladoxylon mirabile to that on
which the genera Arctopodium[516] and Hierogramma[517] were founded is a
very small step: the vascular tissue has the same characters both as regards
gross and minute anatomy, but there is no evidence of cambial activity in
the stems referred to the two latter genera, a difference in itself hardly
worthy of generic recognition.
ii. Leaves. Before describing a second type of stem referred to
Cladoxylon it is important to consider briefly such evidence as we have as
to the vascular supply of the leaves. Nothing is known of the reproductive
organs and there is no satisfactory information with regard to the form of
the fronds. Solms-Laubach has described the only known example of a
lateral branch of a Cladoxylon stem (fig. 459, E): this has a single
concentric vascular strand of plate-like form with two blunt projections and
there are four protoxylem-groups, two in the angle of the plate and two at
the base of the projections. The structure is essentially fern-like; the xylem
is wholly primary. This type of vascular strand agrees fairly closely with
that of a petiole described by Unger as Megalorhachis elliptica, a section of
which is in the Museum of the Geological Survey[518]. The petiole is oval in
section and laterally winged, and the meristele is tangentially elongated and
has two blunt projections almost identical with those in fig. 459, F. There is
no evidence as to the nature of the supporting stem, but there can be little
doubt as to the close connexion with Megalorhachis and the section shown
in fig. 459, F. In a note published in 1908 P. Bertrand stated that he had
identified several of Unger’s genera as stems which bore leaf-traces having
the form and structure of Clepsydropsis, one of the types referred by Unger
to the Rhachiopterideae and described in the second volume of this work[519]
as a Coenopteridean petiole. Bertrand points out that in the oval or plate-
like steles of Cladoxylon, Arctopodium, Hierogramma, etc., there is a single
protoxylem group near the distal end of the primary xylem, and he adds that
the leaf-traces were formed of strands cut off from the distal portions of the
vascular plates. Similarly the hour-glass-like leaf-trace in the primary rachis
of Clepsydropsis gives off from each end a ring of xylem to supply a
secondary rachis. These laterally detached annular strands are, he believes,
similar to the leaf-trace cut off from the steles in a Cladoxylon stem. The
conclusion is that Cladoxylon is a fern stem and its leaf-trace represents the
simplest form of the Clepsydropsis type, namely an oval bundle of xylem
with a central protoxylem, which is also the form of the trace given off from
which the genera Arctopodium[516] and Hierogramma[517] were founded is a
very small step: the vascular tissue has the same characters both as regards
gross and minute anatomy, but there is no evidence of cambial activity in
the stems referred to the two latter genera, a difference in itself hardly
worthy of generic recognition.
ii. Leaves. Before describing a second type of stem referred to
Cladoxylon it is important to consider briefly such evidence as we have as
to the vascular supply of the leaves. Nothing is known of the reproductive
organs and there is no satisfactory information with regard to the form of
the fronds. Solms-Laubach has described the only known example of a
lateral branch of a Cladoxylon stem (fig. 459, E): this has a single
concentric vascular strand of plate-like form with two blunt projections and
there are four protoxylem-groups, two in the angle of the plate and two at
the base of the projections. The structure is essentially fern-like; the xylem
is wholly primary. This type of vascular strand agrees fairly closely with
that of a petiole described by Unger as Megalorhachis elliptica, a section of
which is in the Museum of the Geological Survey[518]. The petiole is oval in
section and laterally winged, and the meristele is tangentially elongated and
has two blunt projections almost identical with those in fig. 459, F. There is
no evidence as to the nature of the supporting stem, but there can be little
doubt as to the close connexion with Megalorhachis and the section shown
in fig. 459, F. In a note published in 1908 P. Bertrand stated that he had
identified several of Unger’s genera as stems which bore leaf-traces having
the form and structure of Clepsydropsis, one of the types referred by Unger
to the Rhachiopterideae and described in the second volume of this work[519]
as a Coenopteridean petiole. Bertrand points out that in the oval or plate-
like steles of Cladoxylon, Arctopodium, Hierogramma, etc., there is a single
protoxylem group near the distal end of the primary xylem, and he adds that
the leaf-traces were formed of strands cut off from the distal portions of the
vascular plates. Similarly the hour-glass-like leaf-trace in the primary rachis
of Clepsydropsis gives off from each end a ring of xylem to supply a
secondary rachis. These laterally detached annular strands are, he believes,
similar to the leaf-trace cut off from the steles in a Cladoxylon stem. The
conclusion is that Cladoxylon is a fern stem and its leaf-trace represents the
simplest form of the Clepsydropsis type, namely an oval bundle of xylem
with a central protoxylem, which is also the form of the trace given off from
Page 244
the stem of Asterochlaena. Solms[520], while admitting that Bertrand may be
correct in uniting under one genus Cladoxylon and such types as Syncardia,
Hierogramma, and Arctopodium, disagrees with the view that they are
Clepsydropsis stems. A Clepsydropsoid leaf-trace has never been found in
direct association with any of the stems of the Cladoxylon type and such
evidence as there is indicates a leaf-trace of an entirely different form (fig.
459, E). In his more recent memoir on Asterochlaena Bertrand[521] draws
attention to Solms’ figures of a stele of Cladoxylon (fig. 459, C) in which
the distal portion is on the point of being separated as a small annular
strand. This, Bertrand considers, would gradually become converted into a
Clepsydropsis form of stele as it passed to the petiole. Bertrand’s drawings
made from a section of Cladoxylon taeniatum (Ung.) (fig. 459, G) illustrate
successive stages in the departure of a leaf-trace from one of the plate-like
steles of the stem (fig. 459, B). In fig. 459, G, 1, a piece of the stele is
detached and near its extremity is a group of thin-walled cells with
protoxylem: a later stage is seen in fig. 2, and in fig. 3 a small ring of xylem
is being detached which, Bertrand assumes, would later in its course be
converted into the Clepsydropsoid strand (fig. 4), which consists of primary
tissue. The weak point in Bertrand’s contention[522] is the absence of any
proof of a true Clepsydropsoid trace in connexion with a Cladoxylon stem,
and there is a strong probability that the leaf-trace of Cladoxylon has the
form shown in fig. 459, E.
Cladoxylon Kidstoni Solms-Laubach[523].
This species, founded on imperfectly preserved material in Dr Kidston’s
collection from Lower Carboniferous rocks in Berwickshire, is referred to
Cladoxylon on evidence that cannot be regarded as convincing. The type-
specimen consists of a small piece of stem about 3 cm. in breadth showing
three complete oval steles and portions of two others which seem to be in
their original position and probably formed part of a series of peripheral
steles such as those shown in fig. 459, D. Each stele consists mainly of
secondary xylem (fig. 460, A) with some crushed tissue, presumably
phloem, on its outer face. The secondary xylem is narrower on the inner
side of each stele where a wedge-shaped piece is partially detached. In the
centre there is a narrow area parallel to the long axis of the stele containing
crushed tissue which probably consists of parenchyma and primary xylem,
but the preservation is very imperfect. The secondary xylem has a fairly
correct in uniting under one genus Cladoxylon and such types as Syncardia,
Hierogramma, and Arctopodium, disagrees with the view that they are
Clepsydropsis stems. A Clepsydropsoid leaf-trace has never been found in
direct association with any of the stems of the Cladoxylon type and such
evidence as there is indicates a leaf-trace of an entirely different form (fig.
459, E). In his more recent memoir on Asterochlaena Bertrand[521] draws
attention to Solms’ figures of a stele of Cladoxylon (fig. 459, C) in which
the distal portion is on the point of being separated as a small annular
strand. This, Bertrand considers, would gradually become converted into a
Clepsydropsis form of stele as it passed to the petiole. Bertrand’s drawings
made from a section of Cladoxylon taeniatum (Ung.) (fig. 459, G) illustrate
successive stages in the departure of a leaf-trace from one of the plate-like
steles of the stem (fig. 459, B). In fig. 459, G, 1, a piece of the stele is
detached and near its extremity is a group of thin-walled cells with
protoxylem: a later stage is seen in fig. 2, and in fig. 3 a small ring of xylem
is being detached which, Bertrand assumes, would later in its course be
converted into the Clepsydropsoid strand (fig. 4), which consists of primary
tissue. The weak point in Bertrand’s contention[522] is the absence of any
proof of a true Clepsydropsoid trace in connexion with a Cladoxylon stem,
and there is a strong probability that the leaf-trace of Cladoxylon has the
form shown in fig. 459, E.
Cladoxylon Kidstoni Solms-Laubach[523].
This species, founded on imperfectly preserved material in Dr Kidston’s
collection from Lower Carboniferous rocks in Berwickshire, is referred to
Cladoxylon on evidence that cannot be regarded as convincing. The type-
specimen consists of a small piece of stem about 3 cm. in breadth showing
three complete oval steles and portions of two others which seem to be in
their original position and probably formed part of a series of peripheral
steles such as those shown in fig. 459, D. Each stele consists mainly of
secondary xylem (fig. 460, A) with some crushed tissue, presumably
phloem, on its outer face. The secondary xylem is narrower on the inner
side of each stele where a wedge-shaped piece is partially detached. In the
centre there is a narrow area parallel to the long axis of the stele containing
crushed tissue which probably consists of parenchyma and primary xylem,
but the preservation is very imperfect. The secondary xylem has a fairly
Page 245
compact structure and the rays are narrow, 1–10 cells in depth. The pits of
the tracheids are described by Solms as scalariform with occasionally two
rows of elliptical pits on the radial walls. A careful examination of the type-
specimen leads me to describe the pits as uniseriate and transversely
elongated, very like those of Protopitys, or biseriate and almost circular like
those of Conifers, the pits of the two rows being alternate or sometimes
opposite (fig. 460, C): in places three rows of bordered pits are present.
There is a certain degree of resemblance between the steles of this species
and those of the South African stem Rhexoxylon[524], but the data are
inadequate for a satisfactory comparison.
the tracheids are described by Solms as scalariform with occasionally two
rows of elliptical pits on the radial walls. A careful examination of the type-
specimen leads me to describe the pits as uniseriate and transversely
elongated, very like those of Protopitys, or biseriate and almost circular like
those of Conifers, the pits of the two rows being alternate or sometimes
opposite (fig. 460, C): in places three rows of bordered pits are present.
There is a certain degree of resemblance between the steles of this species
and those of the South African stem Rhexoxylon[524], but the data are
inadequate for a satisfactory comparison.
Page 246
Fig. 460.
A, C. A single stele and tracheids of Cladoxylon Kidstoni. (Kidston Coll.
630 B, 630 C.)
B. Cladoxylon mirabile, part of a stele. (Museum of Practical Geology,
15872.)
There is a close similarity between the vascular systems of Cladoxylon
and Medullosa, but an obvious difference is the substitution of the oval,
transversely elongated, pits on the xylem elements for the multiseriate
pitting of Medullosa. In Cladoxylon Kidstoni the pitting shows transitional
A, C. A single stele and tracheids of Cladoxylon Kidstoni. (Kidston Coll.
630 B, 630 C.)
B. Cladoxylon mirabile, part of a stele. (Museum of Practical Geology,
15872.)
There is a close similarity between the vascular systems of Cladoxylon
and Medullosa, but an obvious difference is the substitution of the oval,
transversely elongated, pits on the xylem elements for the multiseriate
pitting of Medullosa. In Cladoxylon Kidstoni the pitting shows transitional
Page 247
forms between a narrow scalariform uniseriate type and a biseriate or
triseriate arrangement similar to that in the Araucarineae and Cordaitales. In
Cladoxylon, as limited by Unger, the presence of secondary wood is a
generic feature, but by the inclusion of Arctopodium and other forms this
character no longer holds good. The inclusion of these more fern-like stems
without secondary xylem brings Cladoxylon (in the wider sense) into closer
contact with Asterochlaena, a comparison previously suggested by more
than one author. In Medullosa the development of secondary xylem is on a
larger scale than in Cladoxylon, and the vascular system of the former
genus assumes a more complex form. Moreover the Myeloxylon type of
petiole, which is a distinctive feature of Medullosa, differs widely from any
form of leaf-trace associated with Cladoxylon.
Völkelia. Solms-Laubach.
Völkelia refracta (Goeppert). The generic name Völkelia[525] was
proposed by Solms-Laubach[526] as a substitute for Sphenopteris[527] in the
case of some petrified stems or petioles associated with fragmentary
impressions of fronds from Lower Carboniferous rocks in Silesia. Both
leaf-impressions and petrifactions were included in the genus Sphenopteris:
Solms, while retaining Goeppert’s designation for the leaf fragments,
proposed a new generic name for the petrifactions on the ground that there
is insufficient evidence of their connexion with the leaves. The short
account of Goeppert’s petrified specimen given by Graf Solms-Laubach in
his ‘Fossil Botany[528]’ is supplemented by a fuller description in a later
paper. The fragments of highly compound fronds are characterised by very
small filiform ultimate segments, but the specimens are too imperfect to
afford a clear idea of the habit of the leaf. The ‘stem’ bears a close
superficial resemblance to that described by Unger as Cladoxylon dubium
(fig. 459, C, D) and was regarded by him as an example of that species: it
contains several radially placed steles represented by fairly well-preserved
xylem, but no phloem has been recognised. The steles vary in size and
shape: five reach almost to the centre (fig. 461, A) and smaller xylem
groups occupy a peripheral position. Each stele is excentric in structure and
consists of (i) an outer zone of secondary tracheids of horse-shoe form in
transverse section, but the apparent gap in the secondary xylem on the outer
edge of each stele is due to the crushing of the tracheal tissue and to its
smaller breadth in the distal part of each group; this is shown in fig. 461, B,
triseriate arrangement similar to that in the Araucarineae and Cordaitales. In
Cladoxylon, as limited by Unger, the presence of secondary wood is a
generic feature, but by the inclusion of Arctopodium and other forms this
character no longer holds good. The inclusion of these more fern-like stems
without secondary xylem brings Cladoxylon (in the wider sense) into closer
contact with Asterochlaena, a comparison previously suggested by more
than one author. In Medullosa the development of secondary xylem is on a
larger scale than in Cladoxylon, and the vascular system of the former
genus assumes a more complex form. Moreover the Myeloxylon type of
petiole, which is a distinctive feature of Medullosa, differs widely from any
form of leaf-trace associated with Cladoxylon.
Völkelia. Solms-Laubach.
Völkelia refracta (Goeppert). The generic name Völkelia[525] was
proposed by Solms-Laubach[526] as a substitute for Sphenopteris[527] in the
case of some petrified stems or petioles associated with fragmentary
impressions of fronds from Lower Carboniferous rocks in Silesia. Both
leaf-impressions and petrifactions were included in the genus Sphenopteris:
Solms, while retaining Goeppert’s designation for the leaf fragments,
proposed a new generic name for the petrifactions on the ground that there
is insufficient evidence of their connexion with the leaves. The short
account of Goeppert’s petrified specimen given by Graf Solms-Laubach in
his ‘Fossil Botany[528]’ is supplemented by a fuller description in a later
paper. The fragments of highly compound fronds are characterised by very
small filiform ultimate segments, but the specimens are too imperfect to
afford a clear idea of the habit of the leaf. The ‘stem’ bears a close
superficial resemblance to that described by Unger as Cladoxylon dubium
(fig. 459, C, D) and was regarded by him as an example of that species: it
contains several radially placed steles represented by fairly well-preserved
xylem, but no phloem has been recognised. The steles vary in size and
shape: five reach almost to the centre (fig. 461, A) and smaller xylem
groups occupy a peripheral position. Each stele is excentric in structure and
consists of (i) an outer zone of secondary tracheids of horse-shoe form in
transverse section, but the apparent gap in the secondary xylem on the outer
edge of each stele is due to the crushing of the tracheal tissue and to its
smaller breadth in the distal part of each group; this is shown in fig. 461, B,
Page 248
where the apparent gap is seen to be occupied by distorted and crushed
tracheids, a, identical with those which form the rest of the outer zone (fig.
461, B, b); (ii) a zone of tracheal tissue continuous with and originally
identical in appearance—except that the elements are rather narrower—
with the outer secondary xylem; (iii) an excentrically situated island
composed of tracheids enclosing a small central area occupied by thin-
walled parenchyma. This third region, represented by black patches in fig.
461, A, in all probability represents the primary part of each stele to which
the rest of the tissue has been added by the cambium. A striking feature of
the secondary xylem is the absence of medullary rays: the tracheids
resemble those of Cladoxylon and Protopitys in the transverse elongation of
the pits (fig. 461, D) which form either a single row or several irregularly
distributed rows. The primary xylem consists in the peripheral region of
tracheids with very narrow scalariform pitting which at first sight suggest
close spiral bands (fig. 461, C), while the inner tracheids are either annular
or reticulate and associated with elongated parenchyma. The imperfectly
preserved ground-tissue appears to consist of homogeneous parenchyma
with radially disposed bands of stereome in the outer cortex.
tracheids, a, identical with those which form the rest of the outer zone (fig.
461, B, b); (ii) a zone of tracheal tissue continuous with and originally
identical in appearance—except that the elements are rather narrower—
with the outer secondary xylem; (iii) an excentrically situated island
composed of tracheids enclosing a small central area occupied by thin-
walled parenchyma. This third region, represented by black patches in fig.
461, A, in all probability represents the primary part of each stele to which
the rest of the tissue has been added by the cambium. A striking feature of
the secondary xylem is the absence of medullary rays: the tracheids
resemble those of Cladoxylon and Protopitys in the transverse elongation of
the pits (fig. 461, D) which form either a single row or several irregularly
distributed rows. The primary xylem consists in the peripheral region of
tracheids with very narrow scalariform pitting which at first sight suggest
close spiral bands (fig. 461, C), while the inner tracheids are either annular
or reticulate and associated with elongated parenchyma. The imperfectly
preserved ground-tissue appears to consist of homogeneous parenchyma
with radially disposed bands of stereome in the outer cortex.
Page 249
Fig. 461. Völkelia refracta. A. Transverse section of a specimen in the
Breslau Museum. B. Portion of a stele; a, the crushed xylem on the
outer side; b, the inner side. C. Longitudinal section showing the
median protoxylem. D. Tracheid from the secondary xylem. (After
Solms-Laubach.)
Our knowledge of Völkelia, though far from complete, justifies its
generic separation from Cladoxylon from which it differs in the lack of
medullary rays and in the structure of the primary portion of each stele. In
the form and arrangement of the pits in the secondary tracheids Völkelia
differs from Medullosa and resembles Cladoxylon. The opinion expressed
by P. Bertrand[529] that Völkelia is probably the stem of one of the
Zygopterideae is based on the older accounts of the genus and not on the
fuller description of 1910.
PROTOPITYEAE.
Protopitys. Goeppert.
The only species so far described is that for which Goeppert founded the
genus in 1850, substituting Protopitys[530] for the name Araucarites, adopted
in an earlier paper, on the ground that the structure of the xylem denoted a
Breslau Museum. B. Portion of a stele; a, the crushed xylem on the
outer side; b, the inner side. C. Longitudinal section showing the
median protoxylem. D. Tracheid from the secondary xylem. (After
Solms-Laubach.)
Our knowledge of Völkelia, though far from complete, justifies its
generic separation from Cladoxylon from which it differs in the lack of
medullary rays and in the structure of the primary portion of each stele. In
the form and arrangement of the pits in the secondary tracheids Völkelia
differs from Medullosa and resembles Cladoxylon. The opinion expressed
by P. Bertrand[529] that Völkelia is probably the stem of one of the
Zygopterideae is based on the older accounts of the genus and not on the
fuller description of 1910.
PROTOPITYEAE.
Protopitys. Goeppert.
The only species so far described is that for which Goeppert founded the
genus in 1850, substituting Protopitys[530] for the name Araucarites, adopted
in an earlier paper, on the ground that the structure of the xylem denoted a
Page 250
distinct generic type. The type-species is from the Upper Devonian rocks of
Falkenberg in Silesia.
Protopitys Buchiana Goeppert.
1845. Araucarites Buchianus Goeppert, in Wimmer’s Flor. Schlesien
(edit. ii.) p. 218.
1847. Pinites Goepperti Unger, Chlor. Protog. p. 31.
1847. Dadoxylon Buchianum Endlicher, Syn. Conif. p. 300.
1850. Protopitys Buchiana Goeppert, Foss. Conif. p. 229, Pl. xxxvii. figs.
4–7; Pl. xxxviii. figs. 1, 2.
In his Monograph of Fossil Conifers Goeppert figured a large piece of
stem consisting mainly of secondary wood and described the more
important anatomical features. He recognised the narrow, transversely
elongated, pits on the radial walls of the tracheids as a feature of special
interest indicating a type of pitting transitional between that of Ferns and
Conifers. A further description was given by Kraus[531] who included under
Goeppert’s name both the Falkenberg stem and a second specimen from
Basel though the latter is Triassic in age and a distinct plant; he suggested a
comparison of Protopitys with Sigillaria and Stigmaria rather than with
Conifers. It is, however, to Graf Solms-Laubach[532] that we owe the most
thorough account of this species. Nothing is known of the leaves or
reproductive organs. The largest piece of stem is nearly 1 ft in diameter and
consists mainly of secondary xylem resembling that of Conifers and
Cordaites except in the form of the bordered pits on the radial walls of the
tracheids (fig. 462, D). The centre of the stem is occupied by a
parenchymatous pith, elliptical in transverse section, enclosed by a band of
primary xylem composed of large polygonal tracheids (fig. 462, C, x1)
characterised by a delicate scalariform pitting on all their walls (fig. 462,
E). The primary xylem forms a narrow layer on the sides of the ellipse, 1–3
elements broad (fig. 462, A, B), but it increases in breadth at the ends of the
long axis where the tracheids are intermixed with parenchyma. The primary
xylem and pith-tissue at the ends of the major axis of the central region
assume different forms at different levels, owing to the detachment of leaf-
traces and the consequent formation of foliar gaps as portions of the
primary xylem pass obliquely outwards into the secondary xylem on the
way to the distichously arranged alternate leaves. The diagram, fig. 462, A,
Falkenberg in Silesia.
Protopitys Buchiana Goeppert.
1845. Araucarites Buchianus Goeppert, in Wimmer’s Flor. Schlesien
(edit. ii.) p. 218.
1847. Pinites Goepperti Unger, Chlor. Protog. p. 31.
1847. Dadoxylon Buchianum Endlicher, Syn. Conif. p. 300.
1850. Protopitys Buchiana Goeppert, Foss. Conif. p. 229, Pl. xxxvii. figs.
4–7; Pl. xxxviii. figs. 1, 2.
In his Monograph of Fossil Conifers Goeppert figured a large piece of
stem consisting mainly of secondary wood and described the more
important anatomical features. He recognised the narrow, transversely
elongated, pits on the radial walls of the tracheids as a feature of special
interest indicating a type of pitting transitional between that of Ferns and
Conifers. A further description was given by Kraus[531] who included under
Goeppert’s name both the Falkenberg stem and a second specimen from
Basel though the latter is Triassic in age and a distinct plant; he suggested a
comparison of Protopitys with Sigillaria and Stigmaria rather than with
Conifers. It is, however, to Graf Solms-Laubach[532] that we owe the most
thorough account of this species. Nothing is known of the leaves or
reproductive organs. The largest piece of stem is nearly 1 ft in diameter and
consists mainly of secondary xylem resembling that of Conifers and
Cordaites except in the form of the bordered pits on the radial walls of the
tracheids (fig. 462, D). The centre of the stem is occupied by a
parenchymatous pith, elliptical in transverse section, enclosed by a band of
primary xylem composed of large polygonal tracheids (fig. 462, C, x1)
characterised by a delicate scalariform pitting on all their walls (fig. 462,
E). The primary xylem forms a narrow layer on the sides of the ellipse, 1–3
elements broad (fig. 462, A, B), but it increases in breadth at the ends of the
long axis where the tracheids are intermixed with parenchyma. The primary
xylem and pith-tissue at the ends of the major axis of the central region
assume different forms at different levels, owing to the detachment of leaf-
traces and the consequent formation of foliar gaps as portions of the
primary xylem pass obliquely outwards into the secondary xylem on the
way to the distichously arranged alternate leaves. The diagram, fig. 462, A,
Page 251
shows the inner part of the secondary xylem (see also fig. 462, C, x2) which
at one end, lt, has formed an oval group about to pass out as a leaf-trace: at
the opposite end the strand is detached and divided into two equal branches.
The two swellings of the primary xylem ellipse shown at a in figs. 462, A
and B, are a characteristic feature: these are clearly seen after the leaf-trace
has become detached; at the inner edge of each of them there appears to be
a protoxylem strand. After the formation of a foliar gap these swellings of
the xylem gradually meet and so re-establish continuity below the outgoing
leaf-trace. No protoxylem has been detected in the actual trace, which is
believed to be concentric. The formation of the leaf-gap and the shoulders
bordering it constitute interesting filicinean features, recalling
corresponding characters in solenostelic Ferns. At the upper end of the
diagram, fig. 462, B, the outgoing leaf-trace is undergoing dichotomy while
at the opposite end the trace has passed out of view. The secondary xylem
shows incomplete rings or arcs of narrower elements, which at first sight
give the impression of annual rings: the occurrence of similar incomplete or
pseudo-rings is a common feature in Lepidodendron and other Palaeozoic
stems. The secondary tracheids (54·4μ in tangential diameter, 68·5μ in
radial diameter) have usually a single series of broadly oval bordered pits
on the radial walls with here and there two rows (fig. 462, D). In one case
only were the pits of the medullary rays recognised (fig. 462, F). The rays
are uniseriate, generally 1–2 cells deep, but occasionally 3 cells in depth
and very rarely deeper. The cambium is of the normal type, and in some
specimens secondary phloem was found consisting of bands, 4–5 layers
broad, of stone-cells alternating with tubular thin-walled elements,
presumably sieve-tubes.
at one end, lt, has formed an oval group about to pass out as a leaf-trace: at
the opposite end the strand is detached and divided into two equal branches.
The two swellings of the primary xylem ellipse shown at a in figs. 462, A
and B, are a characteristic feature: these are clearly seen after the leaf-trace
has become detached; at the inner edge of each of them there appears to be
a protoxylem strand. After the formation of a foliar gap these swellings of
the xylem gradually meet and so re-establish continuity below the outgoing
leaf-trace. No protoxylem has been detected in the actual trace, which is
believed to be concentric. The formation of the leaf-gap and the shoulders
bordering it constitute interesting filicinean features, recalling
corresponding characters in solenostelic Ferns. At the upper end of the
diagram, fig. 462, B, the outgoing leaf-trace is undergoing dichotomy while
at the opposite end the trace has passed out of view. The secondary xylem
shows incomplete rings or arcs of narrower elements, which at first sight
give the impression of annual rings: the occurrence of similar incomplete or
pseudo-rings is a common feature in Lepidodendron and other Palaeozoic
stems. The secondary tracheids (54·4μ in tangential diameter, 68·5μ in
radial diameter) have usually a single series of broadly oval bordered pits
on the radial walls with here and there two rows (fig. 462, D). In one case
only were the pits of the medullary rays recognised (fig. 462, F). The rays
are uniseriate, generally 1–2 cells deep, but occasionally 3 cells in depth
and very rarely deeper. The cambium is of the normal type, and in some
specimens secondary phloem was found consisting of bands, 4–5 layers
broad, of stone-cells alternating with tubular thin-walled elements,
presumably sieve-tubes.
Page 252
Fig. 462. Protopitys Buchiana. A, B. Central region of the stem showing
the pith, the primary xylem (black in fig. A) and (A) the inner part
of the secondary xylem; a, shoulders of xylem at the leaf-gaps; lt
leaf-trace; px protoxylem. C. Secondary, x2, and primary xylem, x1.
D. Radial longitudinal section of the secondary xylem. E.
Scalariform tracheid of the primary xylem. F. Pits on the
medullary-ray cells. (After Solms-Laubach.) Fig. 462. Protopitys
Buchiana. A, B. Central region of the stem showing the pith, the
primary xylem (black in fig. A) and (A) the inner part of the
secondary xylem; a, shoulders of xylem at the leaf-gaps; lt leaf-
the pith, the primary xylem (black in fig. A) and (A) the inner part
of the secondary xylem; a, shoulders of xylem at the leaf-gaps; lt
leaf-trace; px protoxylem. C. Secondary, x2, and primary xylem, x1.
D. Radial longitudinal section of the secondary xylem. E.
Scalariform tracheid of the primary xylem. F. Pits on the
medullary-ray cells. (After Solms-Laubach.) Fig. 462. Protopitys
Buchiana. A, B. Central region of the stem showing the pith, the
primary xylem (black in fig. A) and (A) the inner part of the
secondary xylem; a, shoulders of xylem at the leaf-gaps; lt leaf-
Page 253
trace; px protoxylem. C. Secondary, x2, and primary xylem, x1. D.
Radial longitudinal section of the secondary xylem. E. Scalariform
tracheid of the primary xylem. F. Pits on the medullary-ray cells.
(After Solms-Laubach.)
As Solms-Laubach says, it is highly probable that each leaf-trace, which
forks close to its exit from the primary xylem, became further subdivided
before reaching the leaf. Morphologically, Protopitys is of special
importance as a type possessing characters that indicate a connexion with
Conifers or Cordaitean genera, notably the structure of the secondary wood,
while the presence of foliar gaps is a feature reminiscent of Ferns. The
primary xylem resembles that of some of the Palaeozoic arborescent
Lycopodiales, but in Protopitys the interruptions in this tissue are due to the
emission of leaf-bundles, whereas in the discontinuous primary xylem of
some Sigillarias[533] the gaps have no connexion with leaf-traces. Moreover
the distichous leaves of Protopitys and the larger, branched, leaf-traces are
other distinguishing features. The pitting of the primary xylem is like that in
the Lycopodiales and Filicales, while that of the secondary wood shows a
closer approach to the coniferous type. A comparison may also be made
with the transversely elongated pits of Cladoxylon Kidstoni[534].
A piece of wood agreeing anatomically with the Silesian species of
Protopitys has been found in the Yoredale rocks of England[535].
The peculiarities of the genus have been emphasised by Solms-Laubach
by the institution of a family-name Protopityeae: the genus is essentially a
generalised type exhibiting in the structure of its stem both Filicean and
Coniferous features. The bordered pits differ from those in recent Conifers
in their flatter form, but in this respect they exhibit a closer agreement with
the transversely stretched pits of Xenoxylon phyllocladoides Goth.[536], a
Mesozoic species.
Radial longitudinal section of the secondary xylem. E. Scalariform
tracheid of the primary xylem. F. Pits on the medullary-ray cells.
(After Solms-Laubach.)
As Solms-Laubach says, it is highly probable that each leaf-trace, which
forks close to its exit from the primary xylem, became further subdivided
before reaching the leaf. Morphologically, Protopitys is of special
importance as a type possessing characters that indicate a connexion with
Conifers or Cordaitean genera, notably the structure of the secondary wood,
while the presence of foliar gaps is a feature reminiscent of Ferns. The
primary xylem resembles that of some of the Palaeozoic arborescent
Lycopodiales, but in Protopitys the interruptions in this tissue are due to the
emission of leaf-bundles, whereas in the discontinuous primary xylem of
some Sigillarias[533] the gaps have no connexion with leaf-traces. Moreover
the distichous leaves of Protopitys and the larger, branched, leaf-traces are
other distinguishing features. The pitting of the primary xylem is like that in
the Lycopodiales and Filicales, while that of the secondary wood shows a
closer approach to the coniferous type. A comparison may also be made
with the transversely elongated pits of Cladoxylon Kidstoni[534].
A piece of wood agreeing anatomically with the Silesian species of
Protopitys has been found in the Yoredale rocks of England[535].
The peculiarities of the genus have been emphasised by Solms-Laubach
by the institution of a family-name Protopityeae: the genus is essentially a
generalised type exhibiting in the structure of its stem both Filicean and
Coniferous features. The bordered pits differ from those in recent Conifers
in their flatter form, but in this respect they exhibit a closer agreement with
the transversely stretched pits of Xenoxylon phyllocladoides Goth.[536], a
Mesozoic species.
Page 254
Page 255
CHAPTER XXXIII.
CORDAITALES.
A. POROXYLEAE.
Poroxylon. Renault.
In 1879 Renault[537] briefly summarised the anatomical features of some
silicified vegetative shoots from the Permian of Autun for which he
instituted a new family, the Poroxyleae. The more complete account
contains a description of two species, Poroxylon Boysseti and P. Duchartrei:
the latter was afterwards recognised as a stem of Heterangium. Renault
considered this new genus to be closely allied to Sigillaria and
Sigillariopsis and pointed out its resemblance to Cordaites. Additional
species have since been described but as yet the genus has not been found
outside France in Permo-Carboniferous strata of Autun and the St Étienne
district. The results of a more detailed investigation of the anatomy of the
genus were published by Bertrand and Renault in 1882 and since then[538]
Bertrand, Renault, and Scott have added to our knowledge of this
interesting type. In several respects Poroxylon stems present a striking
resemblance to Lyginopteris, but the recent discovery of the genus
Mesoxylon has given greater significance to the characters in which
Poroxylon agrees with representatives of the Cordaitales. Our knowledge of
the genus, though exceptionally full with regard to the anatomy of
vegetative shoots, does not include any precise information as to the
reproductive organs.
The slender cylindrical stems, not exceeding 2–3 cm. in diameter in
specimens so far recorded, bore large broadly linear leaves similar in form
and venation to those of some species of Cordaites which were attached
singly to slightly swollen nodes separated from one another by internodes
several centimetres long. The base of the rather fleshy lamina passes
imperceptibly from the narrow lower portion into a tangentially expanded
petiole which forms a decurrent ridge on the stem. Axillary buds frequently
occur. Little is known of the leaf-impressions, but if Grand’Eury[539] is
CORDAITALES.
A. POROXYLEAE.
Poroxylon. Renault.
In 1879 Renault[537] briefly summarised the anatomical features of some
silicified vegetative shoots from the Permian of Autun for which he
instituted a new family, the Poroxyleae. The more complete account
contains a description of two species, Poroxylon Boysseti and P. Duchartrei:
the latter was afterwards recognised as a stem of Heterangium. Renault
considered this new genus to be closely allied to Sigillaria and
Sigillariopsis and pointed out its resemblance to Cordaites. Additional
species have since been described but as yet the genus has not been found
outside France in Permo-Carboniferous strata of Autun and the St Étienne
district. The results of a more detailed investigation of the anatomy of the
genus were published by Bertrand and Renault in 1882 and since then[538]
Bertrand, Renault, and Scott have added to our knowledge of this
interesting type. In several respects Poroxylon stems present a striking
resemblance to Lyginopteris, but the recent discovery of the genus
Mesoxylon has given greater significance to the characters in which
Poroxylon agrees with representatives of the Cordaitales. Our knowledge of
the genus, though exceptionally full with regard to the anatomy of
vegetative shoots, does not include any precise information as to the
reproductive organs.
The slender cylindrical stems, not exceeding 2–3 cm. in diameter in
specimens so far recorded, bore large broadly linear leaves similar in form
and venation to those of some species of Cordaites which were attached
singly to slightly swollen nodes separated from one another by internodes
several centimetres long. The base of the rather fleshy lamina passes
imperceptibly from the narrow lower portion into a tangentially expanded
petiole which forms a decurrent ridge on the stem. Axillary buds frequently
occur. Little is known of the leaf-impressions, but if Grand’Eury[539] is
Page 256
correct in his identification of certain specimens from French Stephanian
beds as the leaves of Poroxylon, the lamina reached a length of 1 met. and a
breadth of 15–20 cm. In habit the stems probably resembled some of the
larger-leaved Bamboos. The only evidence bearing on the nature of the
reproductive organs is furnished by Grand’Eury who believes that some
Rhabdocarpus seeds and bractless inflorescences associated with the leaves
assigned to Poroxylon belong to that genus.
The single cylindrical stele has a relatively large solid pith, the
perimedullary region being characterised by the occurrence of a row of
primary crescentic strands of centripetal xylem of exarch type, though not
improbably in some cases slightly mesarch, varying in size and shape and
forming single or paired bundles. These strands represent the xylem of
collateral leaf-traces similar to those of Lyginopteris but differing in the
absence of well-defined centrifugal elements: the curved form of some of
the xylem strands gives them an appearance similar to that of the leaf-traces
of Lyginopteris. The leaf-traces, except in the lower part of their course
through the pith, are double and pass through several internodes before the
centripetal tracheids die out. The secondary xylem (fig. 463) is manoxylic
and very similar to that of Lyginopteris though rather less parenchymatous.
The secondary phloem and cambium are often very well preserved. No
endodermis and no distinct pericycle has been recognised. The cortex is
parenchymatous and, like the pith and to some extent the phloem, contains
numerous secretory sacs; in the outer cortex the presence of hypodermal
strands is a prominent feature. At an early stage in the growth of the stem a
deep-seated phellogen forms secondary tissue both externally and internally
and decortication ensues.
beds as the leaves of Poroxylon, the lamina reached a length of 1 met. and a
breadth of 15–20 cm. In habit the stems probably resembled some of the
larger-leaved Bamboos. The only evidence bearing on the nature of the
reproductive organs is furnished by Grand’Eury who believes that some
Rhabdocarpus seeds and bractless inflorescences associated with the leaves
assigned to Poroxylon belong to that genus.
The single cylindrical stele has a relatively large solid pith, the
perimedullary region being characterised by the occurrence of a row of
primary crescentic strands of centripetal xylem of exarch type, though not
improbably in some cases slightly mesarch, varying in size and shape and
forming single or paired bundles. These strands represent the xylem of
collateral leaf-traces similar to those of Lyginopteris but differing in the
absence of well-defined centrifugal elements: the curved form of some of
the xylem strands gives them an appearance similar to that of the leaf-traces
of Lyginopteris. The leaf-traces, except in the lower part of their course
through the pith, are double and pass through several internodes before the
centripetal tracheids die out. The secondary xylem (fig. 463) is manoxylic
and very similar to that of Lyginopteris though rather less parenchymatous.
The secondary phloem and cambium are often very well preserved. No
endodermis and no distinct pericycle has been recognised. The cortex is
parenchymatous and, like the pith and to some extent the phloem, contains
numerous secretory sacs; in the outer cortex the presence of hypodermal
strands is a prominent feature. At an early stage in the growth of the stem a
deep-seated phellogen forms secondary tissue both externally and internally
and decortication ensues.
Page 257
Fig. 463. Poroxylon Edwardsii. A. Transverse section of stem. B. The
central region of another stem of the same species. (A, × 9;
University College Collection; B, from a photograph supplied by
Prof. Bertrand of a specimen in the Renault Collection, Paris.)
The bundle of each leaf-trace is accompanied by an arc of secondary
centrifugal xylem as it passes through the secondary wood and this is
central region of another stem of the same species. (A, × 9;
University College Collection; B, from a photograph supplied by
Prof. Bertrand of a specimen in the Renault Collection, Paris.)
The bundle of each leaf-trace is accompanied by an arc of secondary
centrifugal xylem as it passes through the secondary wood and this is
Page 258
retained in the leaf except in the finer veins. After entering the petiole the
leaf-trace branches and an arc of bundles is produced, the concave side
facing the upper surface of the thick lamina (fig. 464, A). Further reference
is made to the structure of the leaves in the description of Poroxylon
stephanense. The specimens of roots so far described are characterised by a
diarch plate of primary xylem and two masses of secondary vascular tissue
separated by two medullary rays opposite the protoxylems. Bertrand
mentions the occurrence of roots of P. stephanense with more than two
protoxylem strands. The phellogen was produced in the pericycle as in the
roots of recent Gymnosperms. It is suggested by Lignier[540] that some
silicified rootlets from Grand’ Croix (Loire) described by him as Radiculites
reticulatus and at first compared with roots of Sequoia may belong to some
Cordaitalean plant, possibly Poroxylon.
Poroxylon Edwardsii Renault.
This species[541] affords a good illustration of the generic characters
already summarised. The strap-like leaves are fleshy and the occasionally
forked, parallel or slightly divergent, veins are embedded in a homogeneous
mesophyll with hypodermal strands of mechanical tissue. The pith consists
of parenchyma in vertical series with scattered secretory sacs and differs
from that of Cordaites and Mesoxylon in the absence of transverse discs.
There are 13 primary-xylem strands close to the inner edge of the secondary
wood: the centripetal tracheids are scalariform or have multiseriate pitting
like that in the secondary xylem. The structure of the leaf-traces is clearly
shown in fig. 464: the double trace seen in fig. 464, C, has two protoxylem-
strands accompanied by some parenchyma, and these are almost enveloped
by the metaxylem tracheids which abut on the secondary wood. At this
stage in its course, that is just before bending outwards, the centripetal
xylem reaches its maximum development and the trace forms a prominent
and broad twin-strand in striking contrast to the two narrower and
tangentially extended strands shown in fig. 464, E, D. Each of these strands
with a single protoxylem-group would at a higher level assume the broader
and more compact form and contain two protoxylems as in fig. 464, C. The
tracheids of the secondary xylem have 4–7 alternate rows of contiguous
alternate pits on the radial walls: the medullary rays are 2–3 cells broad and
may be 60 cells deep. According to Renault[542] several small oblique pits
occur on the radial walls of the ray cells. The secondary phloem, separated
leaf-trace branches and an arc of bundles is produced, the concave side
facing the upper surface of the thick lamina (fig. 464, A). Further reference
is made to the structure of the leaves in the description of Poroxylon
stephanense. The specimens of roots so far described are characterised by a
diarch plate of primary xylem and two masses of secondary vascular tissue
separated by two medullary rays opposite the protoxylems. Bertrand
mentions the occurrence of roots of P. stephanense with more than two
protoxylem strands. The phellogen was produced in the pericycle as in the
roots of recent Gymnosperms. It is suggested by Lignier[540] that some
silicified rootlets from Grand’ Croix (Loire) described by him as Radiculites
reticulatus and at first compared with roots of Sequoia may belong to some
Cordaitalean plant, possibly Poroxylon.
Poroxylon Edwardsii Renault.
This species[541] affords a good illustration of the generic characters
already summarised. The strap-like leaves are fleshy and the occasionally
forked, parallel or slightly divergent, veins are embedded in a homogeneous
mesophyll with hypodermal strands of mechanical tissue. The pith consists
of parenchyma in vertical series with scattered secretory sacs and differs
from that of Cordaites and Mesoxylon in the absence of transverse discs.
There are 13 primary-xylem strands close to the inner edge of the secondary
wood: the centripetal tracheids are scalariform or have multiseriate pitting
like that in the secondary xylem. The structure of the leaf-traces is clearly
shown in fig. 464: the double trace seen in fig. 464, C, has two protoxylem-
strands accompanied by some parenchyma, and these are almost enveloped
by the metaxylem tracheids which abut on the secondary wood. At this
stage in its course, that is just before bending outwards, the centripetal
xylem reaches its maximum development and the trace forms a prominent
and broad twin-strand in striking contrast to the two narrower and
tangentially extended strands shown in fig. 464, E, D. Each of these strands
with a single protoxylem-group would at a higher level assume the broader
and more compact form and contain two protoxylems as in fig. 464, C. The
tracheids of the secondary xylem have 4–7 alternate rows of contiguous
alternate pits on the radial walls: the medullary rays are 2–3 cells broad and
may be 60 cells deep. According to Renault[542] several small oblique pits
occur on the radial walls of the ray cells. The secondary phloem, separated
Page 259
by a normal cambium from the xylem, forms a broad band of sieve-tubes
with lateral sieve-plates like those in Medullosa anglica alternating with
tangential rows of parenchyma. The cortex is relatively narrow and in older
stems is chiefly occupied by secondary tissue formed from deep-seated
phellogens.
with lateral sieve-plates like those in Medullosa anglica alternating with
tangential rows of parenchyma. The cortex is relatively narrow and in older
stems is chiefly occupied by secondary tissue formed from deep-seated
phellogens.
Page 260
Fig. 464. Poroxylon. A, B, Poroxylon Boysseti. A, transverse section of
leaf in the region of lateral expansion of the petiole; B, portion of
vascular tissue of A. C–E, Poroxylon Edwardsii. C, leaf-trace
showing recent separation of the two protoxylems; D, leaf-trace at
a lower level with more widely separated protoxylems, px; E, leaf-
trace intermediate between C and D. (From photographs supplied
by Prof. Bertrand.)
leaf in the region of lateral expansion of the petiole; B, portion of
vascular tissue of A. C–E, Poroxylon Edwardsii. C, leaf-trace
showing recent separation of the two protoxylems; D, leaf-trace at
a lower level with more widely separated protoxylems, px; E, leaf-
trace intermediate between C and D. (From photographs supplied
by Prof. Bertrand.)
Page 261
Poroxylon Boysseti Renault.
The stems of this species agree closely with those of P. Edwardsii, the
chief difference being in the structure of the secondary phloem which does
not show the regular concentric alternation of sieve-tubes and parenchyma.
Poroxylon stephanense Bertrand and Renault.
This the oldest species, from Stephanian beds at Grand’ Croix, differs in
no essential features from the other representatives of the genus. It is from a
study of the leaves of this type that Bertrand and Renault have obtained
most of the facts with regard to the anatomy of Poroxylon foliage. In the
median region of the fleshy leaf the bundles are characterised by a
comparatively large amount of centripetal xylem accompanied by a
considerable development of secondary centrifugal tracheids: the bundles
are connected laterally by both centripetal and centrifugal xylem and thus at
certain levels in the lamina the vascular tissue has the form of a continuous
plate (fig. 464, A, B). The veins become independent on branching and near
the edge of the lamina they consist only of primary elements. Secretory sacs
of elongated form are scattered in the homogeneous mesophyll, and thick
stereome-strands underlie the epidermis. The epidermal cells are
rectangular and rows of stomata occur on both surfaces.
B. CORDAITEAE.
Cordaites. Unger.
A preliminary statement with regard to nomenclature may serve to
remove possible misconceptions in connexion with the application of the
generic name Cordaites. It has been the general practice to apply this name
to certain forms of linear leaves which are particularly abundant in
Carboniferous and Permian strata in Europe and North America, and in
recent years a few palaeobotanists have substituted Cordaites for
Noeggerathiopsis as the more suitable designation for Permo-Carboniferous
specimens abundant in the rocks of Gondwana Land. It has been customary
to assign to Cordaites certain reproductive shoots, seeds, and stems
described under the generic names Cordaianthus, Cordaicarpus,
Cordaicladus, Cordaioxylon, etc. Stems agreeing anatomically in their main
features with those of recent Araucarineae have long been attributed to
The stems of this species agree closely with those of P. Edwardsii, the
chief difference being in the structure of the secondary phloem which does
not show the regular concentric alternation of sieve-tubes and parenchyma.
Poroxylon stephanense Bertrand and Renault.
This the oldest species, from Stephanian beds at Grand’ Croix, differs in
no essential features from the other representatives of the genus. It is from a
study of the leaves of this type that Bertrand and Renault have obtained
most of the facts with regard to the anatomy of Poroxylon foliage. In the
median region of the fleshy leaf the bundles are characterised by a
comparatively large amount of centripetal xylem accompanied by a
considerable development of secondary centrifugal tracheids: the bundles
are connected laterally by both centripetal and centrifugal xylem and thus at
certain levels in the lamina the vascular tissue has the form of a continuous
plate (fig. 464, A, B). The veins become independent on branching and near
the edge of the lamina they consist only of primary elements. Secretory sacs
of elongated form are scattered in the homogeneous mesophyll, and thick
stereome-strands underlie the epidermis. The epidermal cells are
rectangular and rows of stomata occur on both surfaces.
B. CORDAITEAE.
Cordaites. Unger.
A preliminary statement with regard to nomenclature may serve to
remove possible misconceptions in connexion with the application of the
generic name Cordaites. It has been the general practice to apply this name
to certain forms of linear leaves which are particularly abundant in
Carboniferous and Permian strata in Europe and North America, and in
recent years a few palaeobotanists have substituted Cordaites for
Noeggerathiopsis as the more suitable designation for Permo-Carboniferous
specimens abundant in the rocks of Gondwana Land. It has been customary
to assign to Cordaites certain reproductive shoots, seeds, and stems
described under the generic names Cordaianthus, Cordaicarpus,
Cordaicladus, Cordaioxylon, etc. Stems agreeing anatomically in their main
features with those of recent Araucarineae have long been attributed to
Page 262
Cordaites, but a few years ago a new type of stem was discovered which,
though almost identical with that of Cordaites, is distinguished by the
character of the primary xylem. For this new type the name Mesoxylon[543]
was proposed. Nothing is known as to the reproductive organs borne on
Mesoxylon stems, but the leaves are externally at least indistinguishable
from those referred to Cordaites. It is therefore obvious that when we apply
the name Cordaites to leaves or other plant-organs, under that designation
are undoubtedly included specimens belonging both to Mesoxylon stems
and to stems with the characters of Cordaites (Cordaioxylon). Further
research may enable us to subdivide Cordaites into more precisely defined
types distinguished by well-marked morphological characters, but at present
the only course would seem to be to restrict the term Mesoxylon to petrified
stems exhibiting the features of that genus and to retain Cordaites as a
comprehensive designation in accordance with the general account of the
genus given in the following pages. This widely distributed and mainly
Palaeozoic genus is especially well represented in the coalfields of France
where in some localities it contributed largely to the formation of seams of
coal[544], and it is chiefly from the researches of French Palaeobotanists that
our knowledge of its morphology is derived. Cordaites has shared the fate
of most other abundant fossil plants in the distribution of its disjuncta
membra among several genera and classes, but on the whole the
information that is now available enables us to reconstruct the complete
plant with a greater degree of confidence than is usually attainable.
Cordaites may be described as a forest-tree closely resembling in habit
and probably in size the recent Conifer Agathis, more especially such
species as A. macrophyllus, A. vitiensis and others with leaves considerably
longer than those of the Kauri Pine (A. australis)[545]. The main stem
reached a considerable height before giving off scattered branches bearing
spirally disposed, sessile, and often crowded leaves[546] like the foliage of
Agathis. The absence of any evidence of a two-ranked arrangement of
leaves on lateral branches suggests a general tendency towards a vertical
rather than a horizontal direction of growth. The sessile and closely set
leaves for the most part of leathery texture vary considerably in length and
breadth in different types (figs. 466–472): in some the broadly linear lamina
with its parallel veins and perfectly constructed [Symbol: I]-shaped girders
(fig. 465) reached a length of nearly 100 cm., in shape like the blade of a
straight broad-sword or the leaves of a Yucca, torn by the wind into strips;
though almost identical with that of Cordaites, is distinguished by the
character of the primary xylem. For this new type the name Mesoxylon[543]
was proposed. Nothing is known as to the reproductive organs borne on
Mesoxylon stems, but the leaves are externally at least indistinguishable
from those referred to Cordaites. It is therefore obvious that when we apply
the name Cordaites to leaves or other plant-organs, under that designation
are undoubtedly included specimens belonging both to Mesoxylon stems
and to stems with the characters of Cordaites (Cordaioxylon). Further
research may enable us to subdivide Cordaites into more precisely defined
types distinguished by well-marked morphological characters, but at present
the only course would seem to be to restrict the term Mesoxylon to petrified
stems exhibiting the features of that genus and to retain Cordaites as a
comprehensive designation in accordance with the general account of the
genus given in the following pages. This widely distributed and mainly
Palaeozoic genus is especially well represented in the coalfields of France
where in some localities it contributed largely to the formation of seams of
coal[544], and it is chiefly from the researches of French Palaeobotanists that
our knowledge of its morphology is derived. Cordaites has shared the fate
of most other abundant fossil plants in the distribution of its disjuncta
membra among several genera and classes, but on the whole the
information that is now available enables us to reconstruct the complete
plant with a greater degree of confidence than is usually attainable.
Cordaites may be described as a forest-tree closely resembling in habit
and probably in size the recent Conifer Agathis, more especially such
species as A. macrophyllus, A. vitiensis and others with leaves considerably
longer than those of the Kauri Pine (A. australis)[545]. The main stem
reached a considerable height before giving off scattered branches bearing
spirally disposed, sessile, and often crowded leaves[546] like the foliage of
Agathis. The absence of any evidence of a two-ranked arrangement of
leaves on lateral branches suggests a general tendency towards a vertical
rather than a horizontal direction of growth. The sessile and closely set
leaves for the most part of leathery texture vary considerably in length and
breadth in different types (figs. 466–472): in some the broadly linear lamina
with its parallel veins and perfectly constructed [Symbol: I]-shaped girders
(fig. 465) reached a length of nearly 100 cm., in shape like the blade of a
straight broad-sword or the leaves of a Yucca, torn by the wind into strips;
Page 263
in other forms the lamina is shorter and more obovate, while in some the
leafy shoots must have looked like slender stems of the smaller-leaved
Bamboos. There is no proof that young vegetative branches with their
spirally rolled leaves[547] were protected by bud-scales, but some oval
triangular scales (fig. 468, C), occasionally found in association with larger
foliage-leaves, may have served that purpose. The branches from which
leaves had recently fallen at the time of fossilisation are characterised by
transversely elongated oval scars, occasionally showing a slightly curved
row of pits like the marks of leaf-traces on the scars of a Horse Chestnut,
sometimes terminating a feebly projecting decurrent leaf-cushion (fig. 466,
C). The leaves persisted for a comparatively long period as in Araucaria
imbricata, and on older leafless branches the scars are transversely
stretched; the leaf-cushion loses its individuality and eventually the
development of secondary cortical tissue causes the exfoliation of the
superficial bark.
In the form and structure of the fertile shoots Cordaites parts company
with Agathis; the trees bore no cones in the ordinary sense, but unisexual
inflorescences—whether on one plant or on different individuals is
uncertain—were produced in the axils or from a supra-axillary position as
compound spikes or compact racemes. Both the longer female shoots and
the shorter and more compact male branches are constructed on a similar
plan. The ovulate inflorescence may exceed 30 cm. in length (fig. 479); a
stout axis bears two-ranked linear bracts subtending short lateral bud-like
shoots with one or several sessile or stalked ovules (fig. 480) between the
sterile scales. The seeds are platyspermic and agree much more closely with
those of Cycads and Gingko than with the seeds of Conifers. The male
inflorescence is on a smaller scale, in habit not unlike the elongated male
shoot of Cephalotaxus pedunculata and some other Conifers; each bract
subtends a small oval bud composed of imbricate scales and highly
modified microsporophylls borne singly or in clusters (figs. 481, F; 482). A
microsporophyll consists of a comparatively long pedicel bearing at its apex
a few long microsporangia. The term microsporophyll implies a
morphological interpretation which is not accepted by all palaeobotanists,
some of whom prefer to regard the microsporangia as stamens or
microsporophylls reduced to their simplest terms and sessile on an
elongated flower-stalk.
leafy shoots must have looked like slender stems of the smaller-leaved
Bamboos. There is no proof that young vegetative branches with their
spirally rolled leaves[547] were protected by bud-scales, but some oval
triangular scales (fig. 468, C), occasionally found in association with larger
foliage-leaves, may have served that purpose. The branches from which
leaves had recently fallen at the time of fossilisation are characterised by
transversely elongated oval scars, occasionally showing a slightly curved
row of pits like the marks of leaf-traces on the scars of a Horse Chestnut,
sometimes terminating a feebly projecting decurrent leaf-cushion (fig. 466,
C). The leaves persisted for a comparatively long period as in Araucaria
imbricata, and on older leafless branches the scars are transversely
stretched; the leaf-cushion loses its individuality and eventually the
development of secondary cortical tissue causes the exfoliation of the
superficial bark.
In the form and structure of the fertile shoots Cordaites parts company
with Agathis; the trees bore no cones in the ordinary sense, but unisexual
inflorescences—whether on one plant or on different individuals is
uncertain—were produced in the axils or from a supra-axillary position as
compound spikes or compact racemes. Both the longer female shoots and
the shorter and more compact male branches are constructed on a similar
plan. The ovulate inflorescence may exceed 30 cm. in length (fig. 479); a
stout axis bears two-ranked linear bracts subtending short lateral bud-like
shoots with one or several sessile or stalked ovules (fig. 480) between the
sterile scales. The seeds are platyspermic and agree much more closely with
those of Cycads and Gingko than with the seeds of Conifers. The male
inflorescence is on a smaller scale, in habit not unlike the elongated male
shoot of Cephalotaxus pedunculata and some other Conifers; each bract
subtends a small oval bud composed of imbricate scales and highly
modified microsporophylls borne singly or in clusters (figs. 481, F; 482). A
microsporophyll consists of a comparatively long pedicel bearing at its apex
a few long microsporangia. The term microsporophyll implies a
morphological interpretation which is not accepted by all palaeobotanists,
some of whom prefer to regard the microsporangia as stamens or
microsporophylls reduced to their simplest terms and sessile on an
elongated flower-stalk.
Page 264
The stem agrees very closely in its more important features with that of
an Araucaria or an Agathis: the primary xylem forms the inner surface of
the thick cylinder of secondary wood, merging gradually into it as in recent
Conifers; there are no separate bundles of primary centripetal xylem. The
medullary rays are narrow: in other words the secondary xylem is of the
pycnoxylic type. The pitting of the tracheids is Araucarian and, as in
Agathis, the leaf-traces arise as twin-bundles. The pith is larger than in the
Araucarineae and more homogeneous in structure; it shares with the pith of
Juglans and some other recent plants an almost constant tendency to
assume a discoid structure. Anatomically the leaves agree more closely in
the structure of the vascular bundles with Cycads than with Conifers though
there are points of contact with both of these classes. The roots branch
freely and their horizontally extended arms (figs. 468, A; 478) suggest
growth in swampy ground; anatomically they conform to the recent
Gymnospermous type and there is good evidence that in some cases fungal
mycelia lived symbiotically in the cortex of coralline rootlets.
Sternberg[548] figured some leaves of Cordaites from Carboniferous rocks
in Bohemia under the generic name Flabellaria in the belief that they
belonged to a Palm. Brongniart substituted a new name Pycnophyllum[549]
on the ground that Corda had disproved the supposed relationship with
Monocotyledons. The name Cordaites was instituted by Unger[550], his
definition being based on leaf-form as well as on stem-anatomy. It has
recently been proposed to revive the forgotten designation
Pycnophyllum[551], but the reasons given are hardly likely to induce botanists
to discard the familiar generic name which perpetuates the memory of
Corda. As already pointed out, the name Cordaites, even though employed
in what has always been regarded a legitimate sense, is no doubt often
given to specimens of some other allied member of the Cordaitales which
can only be recognised as such in the case of more completely preserved
material. The naming of wood of the Cordaitean type, but which may
equally well belong to another genus, raises a difficult question: if there is
satisfactory evidence from collateral sources that the wood is that of a
Cordaites Grand’Eury’s name Cordaixylon[552] or Schenk’s form
Cordaioxylon[553] may be used, though there seems to be no adequate reason
against the use of the name Cordaites. If there is no confirmatory evidence
available and it is impossible to say whether the wood is that of a Conifer or
a Cordaites, or some other plant with the same type of secondary xylem,
an Araucaria or an Agathis: the primary xylem forms the inner surface of
the thick cylinder of secondary wood, merging gradually into it as in recent
Conifers; there are no separate bundles of primary centripetal xylem. The
medullary rays are narrow: in other words the secondary xylem is of the
pycnoxylic type. The pitting of the tracheids is Araucarian and, as in
Agathis, the leaf-traces arise as twin-bundles. The pith is larger than in the
Araucarineae and more homogeneous in structure; it shares with the pith of
Juglans and some other recent plants an almost constant tendency to
assume a discoid structure. Anatomically the leaves agree more closely in
the structure of the vascular bundles with Cycads than with Conifers though
there are points of contact with both of these classes. The roots branch
freely and their horizontally extended arms (figs. 468, A; 478) suggest
growth in swampy ground; anatomically they conform to the recent
Gymnospermous type and there is good evidence that in some cases fungal
mycelia lived symbiotically in the cortex of coralline rootlets.
Sternberg[548] figured some leaves of Cordaites from Carboniferous rocks
in Bohemia under the generic name Flabellaria in the belief that they
belonged to a Palm. Brongniart substituted a new name Pycnophyllum[549]
on the ground that Corda had disproved the supposed relationship with
Monocotyledons. The name Cordaites was instituted by Unger[550], his
definition being based on leaf-form as well as on stem-anatomy. It has
recently been proposed to revive the forgotten designation
Pycnophyllum[551], but the reasons given are hardly likely to induce botanists
to discard the familiar generic name which perpetuates the memory of
Corda. As already pointed out, the name Cordaites, even though employed
in what has always been regarded a legitimate sense, is no doubt often
given to specimens of some other allied member of the Cordaitales which
can only be recognised as such in the case of more completely preserved
material. The naming of wood of the Cordaitean type, but which may
equally well belong to another genus, raises a difficult question: if there is
satisfactory evidence from collateral sources that the wood is that of a
Cordaites Grand’Eury’s name Cordaixylon[552] or Schenk’s form
Cordaioxylon[553] may be used, though there seems to be no adequate reason
against the use of the name Cordaites. If there is no confirmatory evidence
available and it is impossible to say whether the wood is that of a Conifer or
a Cordaites, or some other plant with the same type of secondary xylem,
Page 265
Endlicher’s term Dadoxylon[554] is most conveniently employed. The
confusion liable to follow from the use of the two generic names Dadoxylon
and Araucarioxylon for wood of the same type differing only in geological
age is an argument in favour of extending Dadoxylon to all specimens
having certain anatomical characters, which cannot be certainly assigned
either to the Araucarineae or the Cordaitales, irrespective of geological age.
The term Cordaicladus sometimes applied to branches is hardly necessary,
but the subgeneric names Eu-Cordaites, Dory-Cordaites, and Poa-
Cordaites, instituted by Grand’Eury for different forms of leaf, are
frequently employed and serve a useful purpose as descriptive terms though
the characters which they connote are of small importance and by no means
always well defined or constant. For inflorescences it is customary to adopt
the name Cordaianthus suggested by Grand’Eury as a substitute for
Antholithus and some other terms. The same author uses Rhizo-Cordaites
for roots.
The nomenclature of seeds is more difficult: in a few instances seeds
occur in organic connexion with Cordaitean shoots, but there is no doubt
that many platyspermic Palaeozoic seeds preserved as detached fossils
belong to Cordaites or some other member of the group. The difficulty is
that in the present state of knowledge we cannot definitely determine in
many cases whether a seed is Cordaitean or whether it belonged to a genus
of Pteridosperms. For this reason the account of several seeds that were
probably borne on Cordaites or some allied genus is given in a later chapter
devoted to Gymnospermous seeds. There is no doubt that under the generic
names Cardiocarpus, Cordaicarpus, and Samaropsis are included true
Cordaitean seeds, though it would be incorrect to say that all the seeds so
named belong to members of the Cordaitales.
Cordaites reached its maximum development in the Carboniferous and
Permian periods; the genus or some closely allied types persisted into the
Triassic and Rhaetic periods, and there is reason to believe that the group
was represented in some post-Rhaetic floras. The genus is one of many
remarkable examples of the high degree of specialisation attained by
Palaeozoic plants. The complex mechanisms represented by Cordaites and
similar types give force to the conviction that we cannot hope to penetrate
below the higher branches of the genealogical tree which had its roots in a
period of the earth’s history inaccessible to botanical investigation. The
confusion liable to follow from the use of the two generic names Dadoxylon
and Araucarioxylon for wood of the same type differing only in geological
age is an argument in favour of extending Dadoxylon to all specimens
having certain anatomical characters, which cannot be certainly assigned
either to the Araucarineae or the Cordaitales, irrespective of geological age.
The term Cordaicladus sometimes applied to branches is hardly necessary,
but the subgeneric names Eu-Cordaites, Dory-Cordaites, and Poa-
Cordaites, instituted by Grand’Eury for different forms of leaf, are
frequently employed and serve a useful purpose as descriptive terms though
the characters which they connote are of small importance and by no means
always well defined or constant. For inflorescences it is customary to adopt
the name Cordaianthus suggested by Grand’Eury as a substitute for
Antholithus and some other terms. The same author uses Rhizo-Cordaites
for roots.
The nomenclature of seeds is more difficult: in a few instances seeds
occur in organic connexion with Cordaitean shoots, but there is no doubt
that many platyspermic Palaeozoic seeds preserved as detached fossils
belong to Cordaites or some other member of the group. The difficulty is
that in the present state of knowledge we cannot definitely determine in
many cases whether a seed is Cordaitean or whether it belonged to a genus
of Pteridosperms. For this reason the account of several seeds that were
probably borne on Cordaites or some allied genus is given in a later chapter
devoted to Gymnospermous seeds. There is no doubt that under the generic
names Cardiocarpus, Cordaicarpus, and Samaropsis are included true
Cordaitean seeds, though it would be incorrect to say that all the seeds so
named belong to members of the Cordaitales.
Cordaites reached its maximum development in the Carboniferous and
Permian periods; the genus or some closely allied types persisted into the
Triassic and Rhaetic periods, and there is reason to believe that the group
was represented in some post-Rhaetic floras. The genus is one of many
remarkable examples of the high degree of specialisation attained by
Palaeozoic plants. The complex mechanisms represented by Cordaites and
similar types give force to the conviction that we cannot hope to penetrate
below the higher branches of the genealogical tree which had its roots in a
period of the earth’s history inaccessible to botanical investigation. The
Page 266
plants of the present age are to a large extent the result of evolutionary
tendencies more correctly described as the result of degeneration or
simplification than as the latest phase in a series composed of a succession
of types gradually growing in complexity. Cordaites is essentially a
generalised type, a composite product of an age characterised by an activity
in the elaboration of the complex from the simple. Botanical records
furnished by the geological series available for investigation furnish
evidence of the sorting of characters among gradually diverging races and
of changes in plant-organisation tending towards simplification and
increased efficiency.
Cordaites, using the generic designation in a wide sense, occurs in
Carboniferous and Permian strata in Europe, North America, and China; it
is recorded from several localities in Russia and Siberia for the most part
from Permian rocks, from Permo-Carboniferous (Lower Gondwana) beds in
India, Australia, South Africa, and South America. Wood agreeing generally
in the structure of its secondary tracheids with that of Cordaites is
represented in Devonian rocks, and there can be no doubt as to the
existence of Cordaitalean plants in pre-Carboniferous floras. It is
represented in the Rhaetic flora of Tonkin and has recently been discovered
in strata probably of Rhaetic age in Mexico.
Leaves.
It is important to recognise the fact that leaves included under the generic
name Cordaites were in many cases not borne on stems or branches with
the anatomical characters of Cordaites. Scott in his account of the genus
Mesoxylon says, ‘I feel no doubt that most of the British specimens of
Cordaitean leaves really belong to Mesoxylon, which is a much commoner
type of stem in the Coal Measure petrifications than that of Cordaites
itself[555].’ Some of the Cordaitean leaves were probably attached to stems of
the Poroxylon type[556] and it is not improbable that, as investigations are
extended, additional genera of vegetative shoots will be discovered
provided with leaves similar at least in external characters to those which it
is customary to refer to Cordaites. In the present state of our knowledge we
cannot make use of anatomical characters as criteria by which to distribute
the foliage of the Cordaites form among the genera Cordaites, Mesoxylon,
and Poroxylon, using these names as designations of certain types of
tendencies more correctly described as the result of degeneration or
simplification than as the latest phase in a series composed of a succession
of types gradually growing in complexity. Cordaites is essentially a
generalised type, a composite product of an age characterised by an activity
in the elaboration of the complex from the simple. Botanical records
furnished by the geological series available for investigation furnish
evidence of the sorting of characters among gradually diverging races and
of changes in plant-organisation tending towards simplification and
increased efficiency.
Cordaites, using the generic designation in a wide sense, occurs in
Carboniferous and Permian strata in Europe, North America, and China; it
is recorded from several localities in Russia and Siberia for the most part
from Permian rocks, from Permo-Carboniferous (Lower Gondwana) beds in
India, Australia, South Africa, and South America. Wood agreeing generally
in the structure of its secondary tracheids with that of Cordaites is
represented in Devonian rocks, and there can be no doubt as to the
existence of Cordaitalean plants in pre-Carboniferous floras. It is
represented in the Rhaetic flora of Tonkin and has recently been discovered
in strata probably of Rhaetic age in Mexico.
Leaves.
It is important to recognise the fact that leaves included under the generic
name Cordaites were in many cases not borne on stems or branches with
the anatomical characters of Cordaites. Scott in his account of the genus
Mesoxylon says, ‘I feel no doubt that most of the British specimens of
Cordaitean leaves really belong to Mesoxylon, which is a much commoner
type of stem in the Coal Measure petrifications than that of Cordaites
itself[555].’ Some of the Cordaitean leaves were probably attached to stems of
the Poroxylon type[556] and it is not improbable that, as investigations are
extended, additional genera of vegetative shoots will be discovered
provided with leaves similar at least in external characters to those which it
is customary to refer to Cordaites. In the present state of our knowledge we
cannot make use of anatomical characters as criteria by which to distribute
the foliage of the Cordaites form among the genera Cordaites, Mesoxylon,
and Poroxylon, using these names as designations of certain types of
Page 267
anatomical structure. The specimen reproduced in fig. 465 is in all
probability a piece of a leaf of Cordaites principalis, but on anatomical
grounds Miss Benson[557] has made it the type of a new species, C. Felicis,
and more recently Scott[558] has brought forward evidence supporting the
view that it is a leaf of Mesoxylon. As, therefore, neither impressions nor
petrifications of Cordaitean leaves can in the great majority of cases be
referred with confidence to their respective genera of stems, pending fuller
information the only course would seem to be to use the name Cordaites in
a comprehensive sense indicating in special cases where evidence is
available the more precise systematic position of the specimen. The
classification of Cordaitean leaves proposed by Grand’Eury[559] is based
partly on the form of the lamina and in part on the equality or inequality of
the ‘veins.’ The actual veins, which are embedded in the fairly thick
mesophyll, do not directly affect the superficial ribbing on the carbonised
impression of the leaves and, as seen in fig. 465, the most prominent
hypodermal strands of supporting tissue which would appear as the main
veins or primary ribs on an impression do not correspond in position with
the vascular bundles. Although in some cases the largest stereome-strands
coincide with the veins, forming the upper and lower parts of [Symbol: I]-
shaped girders the centre of which is occupied by the veins, this is by no
means always the case. Grand’Eury has drawn attention to the difference
between the upper and lower surface of some carbonised leaves: in C.
crassifolius (fig. 468, D)[560] there are five to seven finer ribs between each
pair of primary ribs on one face while the other shows ridges and grooves
with a rib corresponding to each. Attention is called on a later page to the
variable character of the ribbing even on different parts of the same lamina.
The lower surface of the leaf, seen in section in fig. 465, would show a
number of approximately equal ribs, or possibly primary ribs (midway
between the veins) separated by two interstitial ribs, while on the upper face
there would be three rather smaller secondary ribs. In a section of a leaf
called by Renault C. crassus[561], a specific name used also by
Lesquereux[562] for an impression of a leaf originally described by Goeppert
as Noeggerathia crassa, there are deep stereome-strands between the veins
next the lower epidermis alternating with single smaller strands, while on
the upper surface the hypodermal strands occur only immediately above the
veins. In a section figured by Felix[563] from North Germany as C. robustus,
the hypodermal stereome forms continuous bands; on the upper face the
probability a piece of a leaf of Cordaites principalis, but on anatomical
grounds Miss Benson[557] has made it the type of a new species, C. Felicis,
and more recently Scott[558] has brought forward evidence supporting the
view that it is a leaf of Mesoxylon. As, therefore, neither impressions nor
petrifications of Cordaitean leaves can in the great majority of cases be
referred with confidence to their respective genera of stems, pending fuller
information the only course would seem to be to use the name Cordaites in
a comprehensive sense indicating in special cases where evidence is
available the more precise systematic position of the specimen. The
classification of Cordaitean leaves proposed by Grand’Eury[559] is based
partly on the form of the lamina and in part on the equality or inequality of
the ‘veins.’ The actual veins, which are embedded in the fairly thick
mesophyll, do not directly affect the superficial ribbing on the carbonised
impression of the leaves and, as seen in fig. 465, the most prominent
hypodermal strands of supporting tissue which would appear as the main
veins or primary ribs on an impression do not correspond in position with
the vascular bundles. Although in some cases the largest stereome-strands
coincide with the veins, forming the upper and lower parts of [Symbol: I]-
shaped girders the centre of which is occupied by the veins, this is by no
means always the case. Grand’Eury has drawn attention to the difference
between the upper and lower surface of some carbonised leaves: in C.
crassifolius (fig. 468, D)[560] there are five to seven finer ribs between each
pair of primary ribs on one face while the other shows ridges and grooves
with a rib corresponding to each. Attention is called on a later page to the
variable character of the ribbing even on different parts of the same lamina.
The lower surface of the leaf, seen in section in fig. 465, would show a
number of approximately equal ribs, or possibly primary ribs (midway
between the veins) separated by two interstitial ribs, while on the upper face
there would be three rather smaller secondary ribs. In a section of a leaf
called by Renault C. crassus[561], a specific name used also by
Lesquereux[562] for an impression of a leaf originally described by Goeppert
as Noeggerathia crassa, there are deep stereome-strands between the veins
next the lower epidermis alternating with single smaller strands, while on
the upper surface the hypodermal strands occur only immediately above the
veins. In a section figured by Felix[563] from North Germany as C. robustus,
the hypodermal stereome forms continuous bands; on the upper face the
Page 268
bands are uniform in thickness but next the lower epidermis they form a
series of ribs.
Grand’Eury’s subgeneric terms Cordaites, Dory-Cordaites, and Poa-
Cordaites have therefore very little value as regards differences in the
ribbing of leaf-impressions: the large size of leaves included in Dory-
Cordaites and the more acute apex of the lamina as compared with the
obtuse apex of smaller leaves of Cordaites are features of limited
application and of minor importance as diagnostic characters. The name
Poa-Cordaites is, however, usefully employed for the narrower linear
leaves with an obtuse apex.
The structure of a Cordaites leaf is clearly shown in fig. 465; the lamina
is approximately 1 mm. thick and there are about 30 veins in a breadth of 2
cm. Strong [Symbol: I]-shaped girders with the webbing composed of
thick-walled cells divide the mesophyll into rectangular compartments: the
intervening hypodermal strands differ in number and size on the two faces.
The epidermis is not preserved: specimens of other leaves show that the
stomata[564] occur in rows on the lower surface. The mesophyll shows no
differentiation into palisade and spongy parenchyma, and in this respect the
leaf agrees with many other forms; but in some leaves the palisade-tissue is
well developed, as in C. lingulatus Ren.[565] The central region of the lamina
consisted of lacunar tissue, portions of which are preserved, with a more
compact sheath of parenchyma enclosing each vein. In some leaves there is
a narrower sheath of thick-walled cells more sharply contrasted with the
mesophyll. The vascular bundles agree in structure with those in the rachis
of a Cycadean frond more closely than with the veins of an Araucarian or
other Coniferous leaf. The xylem consists mainly of centripetal elements
which form a deltoid strand with the protoxylem at the apex, and in close
association with this is a larger or smaller amount of narrower centrifugal
tracheids: in the section shown in fig. 465 the centrifugal xylem may extend
all round the centripetal tracheids, but it usually forms an irregular arch
with its base attached to the sides of the larger tracheal strand, cp, separated,
except at the base of the arch, by a small amount of conjunctive
parenchyma from the centripetal xylem. The phloem is not preserved and is
represented only by a few patches, ph, below the centrifugal tracheids. Dr
Benson[566] in her account of this type of leaf gives additional details and
compares the anatomical features with those in other species. The dual
series of ribs.
Grand’Eury’s subgeneric terms Cordaites, Dory-Cordaites, and Poa-
Cordaites have therefore very little value as regards differences in the
ribbing of leaf-impressions: the large size of leaves included in Dory-
Cordaites and the more acute apex of the lamina as compared with the
obtuse apex of smaller leaves of Cordaites are features of limited
application and of minor importance as diagnostic characters. The name
Poa-Cordaites is, however, usefully employed for the narrower linear
leaves with an obtuse apex.
The structure of a Cordaites leaf is clearly shown in fig. 465; the lamina
is approximately 1 mm. thick and there are about 30 veins in a breadth of 2
cm. Strong [Symbol: I]-shaped girders with the webbing composed of
thick-walled cells divide the mesophyll into rectangular compartments: the
intervening hypodermal strands differ in number and size on the two faces.
The epidermis is not preserved: specimens of other leaves show that the
stomata[564] occur in rows on the lower surface. The mesophyll shows no
differentiation into palisade and spongy parenchyma, and in this respect the
leaf agrees with many other forms; but in some leaves the palisade-tissue is
well developed, as in C. lingulatus Ren.[565] The central region of the lamina
consisted of lacunar tissue, portions of which are preserved, with a more
compact sheath of parenchyma enclosing each vein. In some leaves there is
a narrower sheath of thick-walled cells more sharply contrasted with the
mesophyll. The vascular bundles agree in structure with those in the rachis
of a Cycadean frond more closely than with the veins of an Araucarian or
other Coniferous leaf. The xylem consists mainly of centripetal elements
which form a deltoid strand with the protoxylem at the apex, and in close
association with this is a larger or smaller amount of narrower centrifugal
tracheids: in the section shown in fig. 465 the centrifugal xylem may extend
all round the centripetal tracheids, but it usually forms an irregular arch
with its base attached to the sides of the larger tracheal strand, cp, separated,
except at the base of the arch, by a small amount of conjunctive
parenchyma from the centripetal xylem. The phloem is not preserved and is
represented only by a few patches, ph, below the centrifugal tracheids. Dr
Benson[566] in her account of this type of leaf gives additional details and
compares the anatomical features with those in other species. The dual
Page 269
nature of the xylem like that characteristic of recent Cycads has usually
been regarded as a definite feature of Cordaites leaves; Dr Stopes, on the
other hand, interprets the narrower tracheids (occupying a position similar
to those in fig. 465) in some sections of a leaf identified with C. principalis
from Grand’ Croix, as an inner sheath of transfusion elements (‘primitive
transfusion tissue’) possibly derived from the centripetal xylem with which
it is clearly connected at the sides precisely as in fig. 465; but in the Grand’
Croix leaf the phloem is enclosed within the sheath of narrower tracheids
and not external to it as it is in the section shown in fig. 465 and in a section
of C. lingulatus figured by Dr Stopes. It is, however, difficult to recognise
any fundamental difference between the ‘inner transfusion tissue’ and
centripetal xylem. The cells of the outer sheath in Dr Stopes’s specimens of
C. principalis have bordered pits on their walls and this character is
mentioned also by Renault in other specimens.
Fig. 465. Cordaites leaf (Cordaites Felicis Bens.), probably borne on a
Mesoxylon stem. cp, centripetal xylem; ph, phloem; px,
protoxylem. (Kidston Coll. No. 2194.)
Prof. Lignier[567] has described the structure of fragments of adult leaves
from the Stephanian of Grand’ Croix (Loire) which he refers to Cordaites
lingulatus, and the same author gives an interesting account of the
anatomical features of a bud of the same species. The bud, which resembles
been regarded as a definite feature of Cordaites leaves; Dr Stopes, on the
other hand, interprets the narrower tracheids (occupying a position similar
to those in fig. 465) in some sections of a leaf identified with C. principalis
from Grand’ Croix, as an inner sheath of transfusion elements (‘primitive
transfusion tissue’) possibly derived from the centripetal xylem with which
it is clearly connected at the sides precisely as in fig. 465; but in the Grand’
Croix leaf the phloem is enclosed within the sheath of narrower tracheids
and not external to it as it is in the section shown in fig. 465 and in a section
of C. lingulatus figured by Dr Stopes. It is, however, difficult to recognise
any fundamental difference between the ‘inner transfusion tissue’ and
centripetal xylem. The cells of the outer sheath in Dr Stopes’s specimens of
C. principalis have bordered pits on their walls and this character is
mentioned also by Renault in other specimens.
Fig. 465. Cordaites leaf (Cordaites Felicis Bens.), probably borne on a
Mesoxylon stem. cp, centripetal xylem; ph, phloem; px,
protoxylem. (Kidston Coll. No. 2194.)
Prof. Lignier[567] has described the structure of fragments of adult leaves
from the Stephanian of Grand’ Croix (Loire) which he refers to Cordaites
lingulatus, and the same author gives an interesting account of the
anatomical features of a bud of the same species. The bud, which resembles
Page 270
in general appearance that of Dolerophyllum (fig. 430, p. 133) is 3 cm. long,
oval in transverse section—as the result of compression—and consists of
four convolute leaves and a piece of a fifth. The outer leaves have 75 to 80
veins: the inner laminae are sinistral in their curvature while the three outer
leaves are dextral. In the second, the first in which the tissues are
recognisable, the small desmogen-strands afford some evidence that the
phloem preceded the xylem in the order of differentiation as is often the
case in recent plants. The first tracheids occur almost in the centre of the
desmogen-strand and to these are added the other tracheids of the
centripetal xylem, the oldest elements being spiral, the next scalariform and
the later tracheids reticulate. The centrifugal xylem is formed at a later
stage, and at about the same time are differentiated the elements called by
Dr Stopes the inner sheath and by Lignier the ‘bois diaphragmatique.’
Lignier also describes the development and structural features of the other
tissues of the young leaves and compares the anatomical features of the
French leaves with those of Cordaites Felicis described by Prof. Benson.
The main features of Cordaites leaves are (i) the presence of two kinds of
xylem in the veins, the larger centripetal tracheids, or chief water-
conducting elements, and the narrower tracheids, in some cases attached to
the sides of the centripetal xylem, in others forming free groups, usually
between the protoxylem and the phloem, but sometimes enclosing the
phloem; (ii) the frequent presence of a well-defined sheath of cells round
each vein composed of comparatively thick-walled elements comparable
with the transfusion-tracheids in Conifers; (iii) the presence of lacunar
tissue in the centre of the mesophyll and in some cases of transversely
extended tracheids similar to those in some Podocarp leaves; (iv) a well-
developed system of stereome-strands and [Symbol: I]-shaped girders. The
structural features on the whole suggest a xerophilous type, and the frequent
absence or feeble development of palisade tissue points to diffused rather
than to brilliant sunlight.
The considerable range in size and form among Cordaitean leaves as well
as the obvious dependence on conditions of preservation or growth of such
a relatively unimportant feature as the presence or absence of the so-called
false or interstitial veins—the variability of which has been demonstrated in
several instances—renders specific determination exceedingly difficult. The
following species are briefly described rather with a view to illustrate the
oval in transverse section—as the result of compression—and consists of
four convolute leaves and a piece of a fifth. The outer leaves have 75 to 80
veins: the inner laminae are sinistral in their curvature while the three outer
leaves are dextral. In the second, the first in which the tissues are
recognisable, the small desmogen-strands afford some evidence that the
phloem preceded the xylem in the order of differentiation as is often the
case in recent plants. The first tracheids occur almost in the centre of the
desmogen-strand and to these are added the other tracheids of the
centripetal xylem, the oldest elements being spiral, the next scalariform and
the later tracheids reticulate. The centrifugal xylem is formed at a later
stage, and at about the same time are differentiated the elements called by
Dr Stopes the inner sheath and by Lignier the ‘bois diaphragmatique.’
Lignier also describes the development and structural features of the other
tissues of the young leaves and compares the anatomical features of the
French leaves with those of Cordaites Felicis described by Prof. Benson.
The main features of Cordaites leaves are (i) the presence of two kinds of
xylem in the veins, the larger centripetal tracheids, or chief water-
conducting elements, and the narrower tracheids, in some cases attached to
the sides of the centripetal xylem, in others forming free groups, usually
between the protoxylem and the phloem, but sometimes enclosing the
phloem; (ii) the frequent presence of a well-defined sheath of cells round
each vein composed of comparatively thick-walled elements comparable
with the transfusion-tracheids in Conifers; (iii) the presence of lacunar
tissue in the centre of the mesophyll and in some cases of transversely
extended tracheids similar to those in some Podocarp leaves; (iv) a well-
developed system of stereome-strands and [Symbol: I]-shaped girders. The
structural features on the whole suggest a xerophilous type, and the frequent
absence or feeble development of palisade tissue points to diffused rather
than to brilliant sunlight.
The considerable range in size and form among Cordaitean leaves as well
as the obvious dependence on conditions of preservation or growth of such
a relatively unimportant feature as the presence or absence of the so-called
false or interstitial veins—the variability of which has been demonstrated in
several instances—renders specific determination exceedingly difficult. The
following species are briefly described rather with a view to illustrate the
Page 271
nature of the characters employed by authors than as implying the existence
of so many well-defined types.
Cordaites principalis (Germar).
This species was founded[568] on a large specimen from the Coal
Measures of Wettin showing a fan-like cluster of longitudinally torn and
partially overlapping leaves spread out in the position that would be
assumed on the compression of a shoot with a close spiral phyllotaxis. This
form of Cordaites is the most abundant in the British Coal Measures. The
broadly linear lamina is characterised by an obtuse apex (fig. 466, A), a
tendency to split into strips, close-set parallel ribs, the stouter ribs or veins
separated from one another by 2–3 or it may be as many as 5 finer ribs or
interstitial ‘veins.’ A statement by Weiss that in Germar’s type-specimen the
longitudinal ribbing of the lamina is very imperfectly preserved confirms
the scepticism that is justly felt as to the validity of this character as a
satisfactory specific criterion.
of so many well-defined types.
Cordaites principalis (Germar).
This species was founded[568] on a large specimen from the Coal
Measures of Wettin showing a fan-like cluster of longitudinally torn and
partially overlapping leaves spread out in the position that would be
assumed on the compression of a shoot with a close spiral phyllotaxis. This
form of Cordaites is the most abundant in the British Coal Measures. The
broadly linear lamina is characterised by an obtuse apex (fig. 466, A), a
tendency to split into strips, close-set parallel ribs, the stouter ribs or veins
separated from one another by 2–3 or it may be as many as 5 finer ribs or
interstitial ‘veins.’ A statement by Weiss that in Germar’s type-specimen the
longitudinal ribbing of the lamina is very imperfectly preserved confirms
the scepticism that is justly felt as to the validity of this character as a
satisfactory specific criterion.
Page 272
Fig. 466. A. Cordaites principalis, part of leaf. B. Artisia transversa, pith-
cast. C. Cordaites principalis, branch with leaf-scars. (A, ⅖ nat.
size; B, C, nat. size; Kidston Coll.)
The incomplete example shown in fig. 466, A, is 19·5 cm. long and has a
maximum breadth of 3·5 cm., but the complete leaf was much larger and
tapered gradually to the comparatively broad and slightly concave or
cast. C. Cordaites principalis, branch with leaf-scars. (A, ⅖ nat.
size; B, C, nat. size; Kidston Coll.)
The incomplete example shown in fig. 466, A, is 19·5 cm. long and has a
maximum breadth of 3·5 cm., but the complete leaf was much larger and
tapered gradually to the comparatively broad and slightly concave or
Page 273
amplexicaul base. The narrow elliptical proximal end of a specimen figured
by Kidston[569] from the Middle Coal Measures of Yorkshire is 2·8 cm.
broad indicating that the tangentially expanded leaf-scars on a branch
recently deprived of its foliage must have been a conspicuous feature. In his
synonymy of this species Kidston[570] includes Knorria taxina, a species
founded by Lindley and Hutton[571] on a piece of stem from the Coal
Measures of Newcastle. The type-specimen, as Mr Howse[572] states, is
much larger than the published drawing and closely resembles in the
decurrent leaf-bases with broad apices the piece of stem represented in fig.
466, C, which Kidston identifies as C. principalis. Geinitz[573] refers to this
species the seeds named Cordaicarpus Cordai (Gein.), but there is no
evidence of connexion. Kidston[574] points out that this seed is rare in
Britain: he believes that Cordaianthus Pitcairniae (Lind. and Hutt.) is
probably the inflorescence of C. principalis.
Cordaites principalis occurs in both Carboniferous and Permian strata.
The leaves described by Lesquereux[575] from Pennsylvania as C. Mansfieldi
agree closely with C. principalis. Another similar or possibly identical form
is represented by C. Ottonis Gein.[576]
Cordaites borassifolius (Sternberg).
The leaves of this species, originally referred to Flabellaria[577], resemble
those of C. principalis but differ in the ovate-lanceolate and less obtuse
apex and in the presence of only one or rarely two finer striations between
the stronger ribs. Corda’s drawing[578] affords a good illustration of the
crowded spiral disposition of the foliage comparable with that on an
Agathis shoot. The lamina is usually 4–8 cm. broad but in exceptional cases
may reach a breadth of 12 cm. The species occurs in the Coal Measures,
especially in the Westphalian series and in Permian rocks. Feistmantel[579]
unites with this type Cordaianthus Pitcairniae (fig. 480, A), but as in other
cases there may be a confusion between C. borassifolius and C. principalis.
Leaves described by Lesquereux as C. communis[580] are, as White says, not
distinguished by any well-marked characters from this species. White[581]
figures some good examples of C. borassifolius from Missouri, reaching in
one case a length of 40 cm., showing on the lamina the fructifications of a
fungus, Hysterites cordaitis[582] Grand’Eury. The leaves described from
Canada and the United States as C. Robbii[583] Daws. are closely allied to if
by Kidston[569] from the Middle Coal Measures of Yorkshire is 2·8 cm.
broad indicating that the tangentially expanded leaf-scars on a branch
recently deprived of its foliage must have been a conspicuous feature. In his
synonymy of this species Kidston[570] includes Knorria taxina, a species
founded by Lindley and Hutton[571] on a piece of stem from the Coal
Measures of Newcastle. The type-specimen, as Mr Howse[572] states, is
much larger than the published drawing and closely resembles in the
decurrent leaf-bases with broad apices the piece of stem represented in fig.
466, C, which Kidston identifies as C. principalis. Geinitz[573] refers to this
species the seeds named Cordaicarpus Cordai (Gein.), but there is no
evidence of connexion. Kidston[574] points out that this seed is rare in
Britain: he believes that Cordaianthus Pitcairniae (Lind. and Hutt.) is
probably the inflorescence of C. principalis.
Cordaites principalis occurs in both Carboniferous and Permian strata.
The leaves described by Lesquereux[575] from Pennsylvania as C. Mansfieldi
agree closely with C. principalis. Another similar or possibly identical form
is represented by C. Ottonis Gein.[576]
Cordaites borassifolius (Sternberg).
The leaves of this species, originally referred to Flabellaria[577], resemble
those of C. principalis but differ in the ovate-lanceolate and less obtuse
apex and in the presence of only one or rarely two finer striations between
the stronger ribs. Corda’s drawing[578] affords a good illustration of the
crowded spiral disposition of the foliage comparable with that on an
Agathis shoot. The lamina is usually 4–8 cm. broad but in exceptional cases
may reach a breadth of 12 cm. The species occurs in the Coal Measures,
especially in the Westphalian series and in Permian rocks. Feistmantel[579]
unites with this type Cordaianthus Pitcairniae (fig. 480, A), but as in other
cases there may be a confusion between C. borassifolius and C. principalis.
Leaves described by Lesquereux as C. communis[580] are, as White says, not
distinguished by any well-marked characters from this species. White[581]
figures some good examples of C. borassifolius from Missouri, reaching in
one case a length of 40 cm., showing on the lamina the fructifications of a
fungus, Hysterites cordaitis[582] Grand’Eury. The leaves described from
Canada and the United States as C. Robbii[583] Daws. are closely allied to if
Page 274
not identical with Sternberg’s type. Among other species differing in no
definite character from C. borassifolius is C. lancifolius described by
Schmalhausen[584] from the Permian of Russia.
Cordaites lingulatus Grand’Eury.
The leaves of this species[585] are characterised by the obovate lamina and
bluntly rounded or almost truncate apex; it affords a good illustration of the
uncertainty of the ribbing as a diagnostic character. The lamina of a well-
preserved specimen from the Blanzy coalfield described by Zeiller[586]
reaches a length of 35 cm. and a breadth of 10–11 cm. decreasing to 4 cm.
at the base (fig. 467). In the lower part of the lamina Zeiller describes the
ribs as unequal in prominence, the stronger ones being separated by 1–3
finer ribs, while in the middle and upper portions the ribs appear to be of
equal size. Some of the finer ribs are due to folding of the lamina and are
not represented, as are the ribs due to the presence of stereome-strands, by
dark streaks in the detached cuticle.
definite character from C. borassifolius is C. lancifolius described by
Schmalhausen[584] from the Permian of Russia.
Cordaites lingulatus Grand’Eury.
The leaves of this species[585] are characterised by the obovate lamina and
bluntly rounded or almost truncate apex; it affords a good illustration of the
uncertainty of the ribbing as a diagnostic character. The lamina of a well-
preserved specimen from the Blanzy coalfield described by Zeiller[586]
reaches a length of 35 cm. and a breadth of 10–11 cm. decreasing to 4 cm.
at the base (fig. 467). In the lower part of the lamina Zeiller describes the
ribs as unequal in prominence, the stronger ones being separated by 1–3
finer ribs, while in the middle and upper portions the ribs appear to be of
equal size. Some of the finer ribs are due to folding of the lamina and are
not represented, as are the ribs due to the presence of stereome-strands, by
dark streaks in the detached cuticle.
Page 275
Fig. 467. Cordaites lingulatus. (After Zeiller; ⅚ nat. size.)
Reference has already been made to the anatomical features of leaves of
this species described by Lignier[587] and other authors.
Reference has already been made to the anatomical features of leaves of
this species described by Lignier[587] and other authors.
Page 276
Cordaites grandifolius Lesquereux.
The leaves so named by Lesquereux[588], from the Coal Measures of
Pennsylvania, are distinguished by the elongate cuneate lamina, which
reaches a length of 38 cm. with a narrow base and a slightly rounded
truncate distal end, 16 cm. broad, characterised by a few broad and shallow
crenulations. By contrast with some American specimens in Dr Kidston’s
collection Lesquereux’s figures convey an imperfect idea of the size of the
leaf. A large leaf from the Coal Measures of Belgium described by Cambier
and Renier as a new species of Psygmophyllum, P. Delvali[589], is perhaps
identical with the American type; the lamina of sub-triangular form has
approximately the same dimensions; the veins are numerous and repeatedly
forked. The leaf is much longer than any known Psygmophyllum and the
veins are much more numerous than in P. majus Arb.[590], the largest
representative of that genus. Palaeobotanists who have seen the type-
specimen inform me that they have no doubt as to the Cordaitean nature of
the Belgian specimens, which may be designated Cordaites Delvali. It is,
however, not impossible that Psygmophyllum and Cordaites are allied
genera: our knowledge of the former is limited to unimportant characters.
Cordaites (Dory-Cordaites) palmaeformis (Goeppert).
This Permian type, originally described by Goeppert[591] as Noeggerathia
palmaeformis, is characterised by numerous slender veins: according to
Weiss[592] there may be as many as 3–5 in 1 mm. The leaf is broadly
lanceolate; it tapers gradually to an acute apex reaching a length of 80 cm.
and a breadth of 10 cm. In habit the young foliage-shoots[593] resemble those
of C. principalis and C. borassifolius. Grand’Eury records the frequent
association of Samaropsis seeds with this species; it occurs in Upper
Carboniferous and in Permian strata and is recorded from a few British
localities.
Cordaites (Poa-Cordaites) microstachys Goldenberg.
Weiss[594] first figured this species from drawings supplied by Goldenberg
at whose suggestion the name C. microstachys was adopted. The type-
specimen consists of a slender axis bearing numerous narrow linear leaves
and a few imperfect fertile axillary shoots. A specimen is figured by
Kidston[595] from the Upper Coal Measures of Radstock: it is a rare type in
The leaves so named by Lesquereux[588], from the Coal Measures of
Pennsylvania, are distinguished by the elongate cuneate lamina, which
reaches a length of 38 cm. with a narrow base and a slightly rounded
truncate distal end, 16 cm. broad, characterised by a few broad and shallow
crenulations. By contrast with some American specimens in Dr Kidston’s
collection Lesquereux’s figures convey an imperfect idea of the size of the
leaf. A large leaf from the Coal Measures of Belgium described by Cambier
and Renier as a new species of Psygmophyllum, P. Delvali[589], is perhaps
identical with the American type; the lamina of sub-triangular form has
approximately the same dimensions; the veins are numerous and repeatedly
forked. The leaf is much longer than any known Psygmophyllum and the
veins are much more numerous than in P. majus Arb.[590], the largest
representative of that genus. Palaeobotanists who have seen the type-
specimen inform me that they have no doubt as to the Cordaitean nature of
the Belgian specimens, which may be designated Cordaites Delvali. It is,
however, not impossible that Psygmophyllum and Cordaites are allied
genera: our knowledge of the former is limited to unimportant characters.
Cordaites (Dory-Cordaites) palmaeformis (Goeppert).
This Permian type, originally described by Goeppert[591] as Noeggerathia
palmaeformis, is characterised by numerous slender veins: according to
Weiss[592] there may be as many as 3–5 in 1 mm. The leaf is broadly
lanceolate; it tapers gradually to an acute apex reaching a length of 80 cm.
and a breadth of 10 cm. In habit the young foliage-shoots[593] resemble those
of C. principalis and C. borassifolius. Grand’Eury records the frequent
association of Samaropsis seeds with this species; it occurs in Upper
Carboniferous and in Permian strata and is recorded from a few British
localities.
Cordaites (Poa-Cordaites) microstachys Goldenberg.
Weiss[594] first figured this species from drawings supplied by Goldenberg
at whose suggestion the name C. microstachys was adopted. The type-
specimen consists of a slender axis bearing numerous narrow linear leaves
and a few imperfect fertile axillary shoots. A specimen is figured by
Kidston[595] from the Upper Coal Measures of Radstock: it is a rare type in
Page 277
Britain. The species is readily distinguished from C. principalis and similar
forms by the narrow lamina which varies considerably in length, rarely as
long as 30 cm. and not exceeding 1 cm. in breadth. The apex is obtuse and
the ribs are either equal in strength or 1–2 finer striae may alternate with the
stronger ribs. The base of the lamina is 3–4 mm. wide and the leaf-scars
have a slightly arched upper margin and an almost straight lower edge[596].
The foliage of this species, generally regarded as identical with C. linearis
Grand’Eury, bears a close resemblance to that of the Mesozoic genus
Phoenicopsis from which it is distinguished by the occurrence of the leaves
in bunches.
C. gracilis Lesq.[597] is a similar type. The shoot on which Lesquereux
founded his genus Desmiophyllum[598] may perhaps be an example of Poa-
Cordaites. Poa-Cordaites tenuifolius Schmal.[599] from the Permian of
Russia may be identical with C. microstachys.
As examples of other forms of leaf referred to Cordaites, though as in
other cases without any proof of connexion with branches having the
anatomical features of the genus, reference may be made to Cordaites
circularis Grand’Eury[600] from Gard (fig. 468, B) and a smaller leaf from
the same locality compared with C. Lacoei (fig. 468, C) Lesq. Cordaites
circularis is characterised by the almost orbicular lamina traversed by
slightly spreading veins; it recalls some of the larger Cyclopteris pinnules of
Pteridosperm fronds and is indistinguishable from some leaves assigned to
the genus Dolerophyllum[601].
forms by the narrow lamina which varies considerably in length, rarely as
long as 30 cm. and not exceeding 1 cm. in breadth. The apex is obtuse and
the ribs are either equal in strength or 1–2 finer striae may alternate with the
stronger ribs. The base of the lamina is 3–4 mm. wide and the leaf-scars
have a slightly arched upper margin and an almost straight lower edge[596].
The foliage of this species, generally regarded as identical with C. linearis
Grand’Eury, bears a close resemblance to that of the Mesozoic genus
Phoenicopsis from which it is distinguished by the occurrence of the leaves
in bunches.
C. gracilis Lesq.[597] is a similar type. The shoot on which Lesquereux
founded his genus Desmiophyllum[598] may perhaps be an example of Poa-
Cordaites. Poa-Cordaites tenuifolius Schmal.[599] from the Permian of
Russia may be identical with C. microstachys.
As examples of other forms of leaf referred to Cordaites, though as in
other cases without any proof of connexion with branches having the
anatomical features of the genus, reference may be made to Cordaites
circularis Grand’Eury[600] from Gard (fig. 468, B) and a smaller leaf from
the same locality compared with C. Lacoei (fig. 468, C) Lesq. Cordaites
circularis is characterised by the almost orbicular lamina traversed by
slightly spreading veins; it recalls some of the larger Cyclopteris pinnules of
Pteridosperm fronds and is indistinguishable from some leaves assigned to
the genus Dolerophyllum[601].
Page 278
Fig. 468. A, Cordaites root-system (Rhizo-Cordaites); B, Cordaites
circularis leaf; C, Cordaites sp., cf. Cordaites Lacoei; D, Cordaites
crassifolius, upper and lower surface of leaf. (After Grand’Eury.)
The species C. Lacoei was founded by Lesquereux[602] on some detached
specimens 3–12 cm. long and 1·5–5 cm. broad; it is by no means certain
that a specimen referred by Grand’Eury[603] with some hesitation to this
species is Cordaitean.
The generic name Scuto-Cordaites was proposed by Renault[604] for a
specimen from Commentry consisting of a flattened branch bearing a few
imperfectly preserved leaves. The surface of the branch shows semicircular
leaf-scars on decurrent, spirally disposed leaf-cushions and bears a certain
resemblance to a slender stem of a Clathrarian Sigillaria. The leaves of the
type-specimen of Scuto-Cordaites Grand’Euryi appear to be broadly linear,
13 cm. long, the breadth gradually increasing from the base: a short
distance from the proximal end the lamina is broken up into narrow
segments; the veins are ·5 mm. apart with finer striations between them.
Some specimens from Pennsylvania made by Dawson[605] the type of a
new sub-genus and named Dictyo-Cordaites Lecoi agree in shape and
arrangement with some species of Cordaites, but differ in an occasional
circularis leaf; C, Cordaites sp., cf. Cordaites Lacoei; D, Cordaites
crassifolius, upper and lower surface of leaf. (After Grand’Eury.)
The species C. Lacoei was founded by Lesquereux[602] on some detached
specimens 3–12 cm. long and 1·5–5 cm. broad; it is by no means certain
that a specimen referred by Grand’Eury[603] with some hesitation to this
species is Cordaitean.
The generic name Scuto-Cordaites was proposed by Renault[604] for a
specimen from Commentry consisting of a flattened branch bearing a few
imperfectly preserved leaves. The surface of the branch shows semicircular
leaf-scars on decurrent, spirally disposed leaf-cushions and bears a certain
resemblance to a slender stem of a Clathrarian Sigillaria. The leaves of the
type-specimen of Scuto-Cordaites Grand’Euryi appear to be broadly linear,
13 cm. long, the breadth gradually increasing from the base: a short
distance from the proximal end the lamina is broken up into narrow
segments; the veins are ·5 mm. apart with finer striations between them.
Some specimens from Pennsylvania made by Dawson[605] the type of a
new sub-genus and named Dictyo-Cordaites Lecoi agree in shape and
arrangement with some species of Cordaites, but differ in an occasional
Page 279
anastomosis of the veins as in Psygmophyllum flabellatum. It is, however,
impossible to determine the true nature of the fossils from the published
figures.
Cordaitean leaves from India, the Southern Hemisphere, and Siberia.
Noeggerathiopsis, Feistmantel; Rhiptozamites, Schmalhausen;
Euryphyllum, Feistmantel.
{ Cordaites aequalis Goeppert.
Cordaites (Noeggerathiopsis) Hislopi (Bunbury).
In 1845 Goeppert[606] instituted the species Noeggerathia aequalis (fig.
469) and N. distans for incomplete broadly linear and obovate leaves, from
Siberian Permian strata, having a contracted base and equal parallel veins.
The specimens so named are no doubt specifically identical. Goeppert’s
species N. aequalis has recently been carefully investigated by Zalessky[607]
who agrees with Kosmovsky[608] in identifying it with Noeggerathiopsis
Hislopi (Bunb.) and Rhiptozamites Goepperti Schmal. Schmalhausen[609]
had previously pointed out the probable identity of his species with
Noeggerathia palmaeformis Goepp. (= Cordaites). The question of specific
identity of these leaves from different localities and of other hardly
distinguishable forms is of secondary importance; the main point is that
they are all examples of Cordaitean leaves, Cordaites or some allied genus,
and point to the existence of this group of Gymnosperms during Permo-
Carboniferous times in Siberia, China, India, Australia, South Africa, and S.
America, also in the Rhaetic floras of Tonkin[610] and Mexico[611]. The
fragments from Devonian strata at Iguana Creek, Australia, named by
McCoy[612] Cordaites australis are probably pieces of the rachis of some
large frond.
impossible to determine the true nature of the fossils from the published
figures.
Cordaitean leaves from India, the Southern Hemisphere, and Siberia.
Noeggerathiopsis, Feistmantel; Rhiptozamites, Schmalhausen;
Euryphyllum, Feistmantel.
{ Cordaites aequalis Goeppert.
Cordaites (Noeggerathiopsis) Hislopi (Bunbury).
In 1845 Goeppert[606] instituted the species Noeggerathia aequalis (fig.
469) and N. distans for incomplete broadly linear and obovate leaves, from
Siberian Permian strata, having a contracted base and equal parallel veins.
The specimens so named are no doubt specifically identical. Goeppert’s
species N. aequalis has recently been carefully investigated by Zalessky[607]
who agrees with Kosmovsky[608] in identifying it with Noeggerathiopsis
Hislopi (Bunb.) and Rhiptozamites Goepperti Schmal. Schmalhausen[609]
had previously pointed out the probable identity of his species with
Noeggerathia palmaeformis Goepp. (= Cordaites). The question of specific
identity of these leaves from different localities and of other hardly
distinguishable forms is of secondary importance; the main point is that
they are all examples of Cordaitean leaves, Cordaites or some allied genus,
and point to the existence of this group of Gymnosperms during Permo-
Carboniferous times in Siberia, China, India, Australia, South Africa, and S.
America, also in the Rhaetic floras of Tonkin[610] and Mexico[611]. The
fragments from Devonian strata at Iguana Creek, Australia, named by
McCoy[612] Cordaites australis are probably pieces of the rachis of some
large frond.
Page 280
Page 281
Fig. 469. A–C, E, Cordaites aequalis; D, Cordaites Clerci. (After
Zalessky; ⅚ nat. size.)
Wieland[613] recently discovered Cordaitean leaves exhibiting a wide
range in size and shape in the Mixteca flora of Mexico in the lower
members of a series which extends from the ‘upper borders of the Rhaetic’
through the Liassic to the lower beds of the Inferior Oolite. These leaves are
referred to Noeggerathiopsis Hislopi, and it is clear from an examination of
photographs received from Dr Wieland, one of which is reproduced in fig.
470, that the Mexican Cordaites cannot be specifically distinguished from
Bunbury’s type as represented by specimens described from India, South
Africa, Siberia, Tonkin, and elsewhere.
The occurrence of Noeggerathiopsis is also recorded by Newberry from
the Rhaetic series of Honduras[614].
Noeggerathiopsis. This genus was founded by Feistmantel[615] for some
leaves from Lower Gondwana rocks in India originally described by
Bunbury[616] as Noeggerathia (Cyclopteris?) Hislopi (figs. 470–472) and
regarded by him as probably Cycadean. Several authors have added to our
knowledge of this widely spread southern type and in many localities the
leaves occur in association with platyspermic seeds of the Samaropsis or
Cordaicarpus type, pieces of stems with Cordaitean leaf-scars, and petrified
wood agreeing in the structure of the secondary xylem with that of
European species of Cordaites. In some Permo-Carboniferous sandstones at
Vereeniging, South Africa, stumps and spreading roots (fig. 478)
resembling those described from France by Grand’Eury (cf. fig. 468, A)
have also been discovered. A remarkable occurrence of roots and prostrate
stems of some forest-tree was recorded some years ago in the bed of the
Vaal river near Vereeniging where the surface of a seam of coal was
exposed over an area of more than two acres[617]. Large branched roots (fig.
478) spreading over the coal for a distance of several feet and thick stems
40–50 ft in length with very few branches and but little decrease in diameter
afford a striking picture of a forest-floor. The frequent occurrence of
Cordaites (Noeggerathiopsis) Hislopi in the associated strata suggests a
reference of the stems and roots to that species. Moreover the structure of
the secondary xylem of some petrified pieces of stem sent to me by Mr
Zalessky; ⅚ nat. size.)
Wieland[613] recently discovered Cordaitean leaves exhibiting a wide
range in size and shape in the Mixteca flora of Mexico in the lower
members of a series which extends from the ‘upper borders of the Rhaetic’
through the Liassic to the lower beds of the Inferior Oolite. These leaves are
referred to Noeggerathiopsis Hislopi, and it is clear from an examination of
photographs received from Dr Wieland, one of which is reproduced in fig.
470, that the Mexican Cordaites cannot be specifically distinguished from
Bunbury’s type as represented by specimens described from India, South
Africa, Siberia, Tonkin, and elsewhere.
The occurrence of Noeggerathiopsis is also recorded by Newberry from
the Rhaetic series of Honduras[614].
Noeggerathiopsis. This genus was founded by Feistmantel[615] for some
leaves from Lower Gondwana rocks in India originally described by
Bunbury[616] as Noeggerathia (Cyclopteris?) Hislopi (figs. 470–472) and
regarded by him as probably Cycadean. Several authors have added to our
knowledge of this widely spread southern type and in many localities the
leaves occur in association with platyspermic seeds of the Samaropsis or
Cordaicarpus type, pieces of stems with Cordaitean leaf-scars, and petrified
wood agreeing in the structure of the secondary xylem with that of
European species of Cordaites. In some Permo-Carboniferous sandstones at
Vereeniging, South Africa, stumps and spreading roots (fig. 478)
resembling those described from France by Grand’Eury (cf. fig. 468, A)
have also been discovered. A remarkable occurrence of roots and prostrate
stems of some forest-tree was recorded some years ago in the bed of the
Vaal river near Vereeniging where the surface of a seam of coal was
exposed over an area of more than two acres[617]. Large branched roots (fig.
478) spreading over the coal for a distance of several feet and thick stems
40–50 ft in length with very few branches and but little decrease in diameter
afford a striking picture of a forest-floor. The frequent occurrence of
Cordaites (Noeggerathiopsis) Hislopi in the associated strata suggests a
reference of the stems and roots to that species. Moreover the structure of
the secondary xylem of some petrified pieces of stem sent to me by Mr
Page 282
Leslie from Vereeniging agrees closely with that of a European Cordaitean
stem.
Fig. 470. Cordaites Fig. 471. Cordaites
(Noeggerathiopsis) Hislopi. From (Noeggerathiopsis) Hislopi. From
Mexico. (After Wieland; ⅚ nat. Vereeniging. (A, ca, ⅕ nat. size; B,
size.) ca, ⅙ nat. size.)
stem.
Fig. 470. Cordaites Fig. 471. Cordaites
(Noeggerathiopsis) Hislopi. From (Noeggerathiopsis) Hislopi. From
Mexico. (After Wieland; ⅚ nat. Vereeniging. (A, ca, ⅕ nat. size; B,
size.) ca, ⅙ nat. size.)
Page 283
Fig. 472. Cordaites (Noeggerathiopsis) Hislopi. From India. (Calcutta
Museum; ⅔ nat. size.)
The leaves of Cordaites (Noeggerathiopsis) Hislopi vary considerably in
size, in some cases reaching a length of 80 cm. (fig. 471); the lamina tapers
gradually from a short distance behind the obtuse apex to a relatively
narrow base: in venation and form the leaves are very similar to those of C.
principalis and other European and North American species. The specimen
from India represented in fig. 472 shows several spathulate leaves attached
in a close spiral to a branch. As White[618] and Zalessky have shown, the
stronger ribs are separated by less prominent striations indicating the
presence of two sizes of hypodermal strands. The obvious resemblance
between Noeggerathiopsis Hislopi and species of Cordaites has long been
recognised and many authors have included Feistmantel’s genus in the
Museum; ⅔ nat. size.)
The leaves of Cordaites (Noeggerathiopsis) Hislopi vary considerably in
size, in some cases reaching a length of 80 cm. (fig. 471); the lamina tapers
gradually from a short distance behind the obtuse apex to a relatively
narrow base: in venation and form the leaves are very similar to those of C.
principalis and other European and North American species. The specimen
from India represented in fig. 472 shows several spathulate leaves attached
in a close spiral to a branch. As White[618] and Zalessky have shown, the
stronger ribs are separated by less prominent striations indicating the
presence of two sizes of hypodermal strands. The obvious resemblance
between Noeggerathiopsis Hislopi and species of Cordaites has long been
recognised and many authors have included Feistmantel’s genus in the
Page 284
Cordaitales[619]. Prof. Zeiller[620] preferred to retain the name
Noeggerathiopsis as a precautionary measure, chiefly on the ground that the
stomata appeared to be less definitely arranged in rows and more scattered
than in the European leaves of Cordaites, and because of the absence of
interstitial veins. We have as yet little information as to the arrangement of
the stomata, but in view of the irregularity in stomatal grouping in recent
leaves this feature is, perhaps, of minor importance. The presence of
interstitial ‘veins’ has now been established in Indian[621] and South
American[622] leaves. In a paper published in 1908[623] the name Cordaites
was substituted for Noeggerathiopsis and Zalessky’s recent work supports
this step. The description by Zalessky of the ribbing in Goeppert’s species
Cordaites aequalis from Siberia shows how uncertain and variable a
character the venation is even in different parts of the same leaf.
Cordaites Clerci Zalessky.
This species (fig. 469, D) was instituted for some small lanceolate or
spathulate leaves from the Petschora basin (Adzva River)[624] reaching a
length of 6 cm. and a breadth of 1 cm. It is separated from Cordaites
aequalis on the ground that the veins are more numerous, as many as 44 in
a breadth of 1 cm.
A recent investigation by Miss Holden[625] of the carbonised cuticles of
some Indian specimens, sent to Cambridge by the Director of the Indian
Geological Survey, and a comparison of them with preparations made from
European Cordaites leaves, have revealed certain distinguishing features
which support Zeiller’s view that the Gondwana-Land leaves, though
similar superficially to those of Cordaites, are probably distinct. It is,
however, impossible in many cases to obtain any information with regard to
epidermal characters, and though it would seem probable that had we a
fuller knowledge of the Indian and southern hemisphere plants represented
for the most part by leaf-impressions well-defined distinguishing features
would be recognised, the comprehensive name Cordaites may conveniently
be retained on the ground that in the absence of well-preserved cuticles no
satisfactory distinguishing features are exhibited by the impressions of
Noeggerathiopsis.
Phylladoderma. Zalessky.
Noeggerathiopsis as a precautionary measure, chiefly on the ground that the
stomata appeared to be less definitely arranged in rows and more scattered
than in the European leaves of Cordaites, and because of the absence of
interstitial veins. We have as yet little information as to the arrangement of
the stomata, but in view of the irregularity in stomatal grouping in recent
leaves this feature is, perhaps, of minor importance. The presence of
interstitial ‘veins’ has now been established in Indian[621] and South
American[622] leaves. In a paper published in 1908[623] the name Cordaites
was substituted for Noeggerathiopsis and Zalessky’s recent work supports
this step. The description by Zalessky of the ribbing in Goeppert’s species
Cordaites aequalis from Siberia shows how uncertain and variable a
character the venation is even in different parts of the same leaf.
Cordaites Clerci Zalessky.
This species (fig. 469, D) was instituted for some small lanceolate or
spathulate leaves from the Petschora basin (Adzva River)[624] reaching a
length of 6 cm. and a breadth of 1 cm. It is separated from Cordaites
aequalis on the ground that the veins are more numerous, as many as 44 in
a breadth of 1 cm.
A recent investigation by Miss Holden[625] of the carbonised cuticles of
some Indian specimens, sent to Cambridge by the Director of the Indian
Geological Survey, and a comparison of them with preparations made from
European Cordaites leaves, have revealed certain distinguishing features
which support Zeiller’s view that the Gondwana-Land leaves, though
similar superficially to those of Cordaites, are probably distinct. It is,
however, impossible in many cases to obtain any information with regard to
epidermal characters, and though it would seem probable that had we a
fuller knowledge of the Indian and southern hemisphere plants represented
for the most part by leaf-impressions well-defined distinguishing features
would be recognised, the comprehensive name Cordaites may conveniently
be retained on the ground that in the absence of well-preserved cuticles no
satisfactory distinguishing features are exhibited by the impressions of
Noeggerathiopsis.
Phylladoderma. Zalessky.
Page 285
Phylladoderma Arberi Zalessky.
Zalessky[626] founded this genus on some Permian leaves from the
Petschora basin (Adzva River) which closely resemble those of Cordaites
but are characterised by a coarser venation. The lanceolate lamina reaches a
length of 18 cm. and a breadth of 4·2 cm.; the veins are 2 mm. apart and
occasionally forked near the base of the leaf. The epidermal cells have
straight walls and stomata are abundant on the lower surface. As Zalessky
says, the systematic position of the leaves is uncertain though they are
probably Cordaitean. The coarseness of the venation is a feature of minor
importance and hardly worthy of generic recognition.
Rhiptozamites Schmalhausen.
This genus was instituted by Schmalhausen[627] for leaves from beds in
the Kusnezk basin regarded by him as Jurassic. These strata are now
recognised as Permian[628] and homotaxial with those from which
Schmalhausen[629] subsequently recorded the same species. The leaves,
though smaller than many of the Indian and South African specimens of
Cordaites (Noeggerathiopsis) Hislopi, may belong to that species. Zeiller
and others definitely assigned the Russian leaves to Cordaites.
Euryphyllum. The Indian leaves for which Feistmantel[630] proposed this
name are, as several writers have pointed out, in all probability referable to
Cordaites.
The general conclusion to be drawn from this imperfect summary of an
extensive literature is that the employment of the generic names
Noeggerathiopsis, Rhiptozamites, Euryphyllum, and others has tended to
exaggerate the difference between the European and Southern botanical
provinces during the Permo-Carboniferous period.
Scale-leaves, seeds, and stems.
The occurrence of small scale-like leaves of the type represented in fig.
468, C, in association with Cordaites (Noeggerathiopsis) Hislopi[631] in
India, Brazil, Siberia, and elsewhere may mean that these organs are scales
of large foliar buds. The occurrence of several forms of platyspermic seeds,
in some cases apparently identical with European forms and sometimes
distinct types, in close association with Cordaites (Noeggerathiopsis)
Zalessky[626] founded this genus on some Permian leaves from the
Petschora basin (Adzva River) which closely resemble those of Cordaites
but are characterised by a coarser venation. The lanceolate lamina reaches a
length of 18 cm. and a breadth of 4·2 cm.; the veins are 2 mm. apart and
occasionally forked near the base of the leaf. The epidermal cells have
straight walls and stomata are abundant on the lower surface. As Zalessky
says, the systematic position of the leaves is uncertain though they are
probably Cordaitean. The coarseness of the venation is a feature of minor
importance and hardly worthy of generic recognition.
Rhiptozamites Schmalhausen.
This genus was instituted by Schmalhausen[627] for leaves from beds in
the Kusnezk basin regarded by him as Jurassic. These strata are now
recognised as Permian[628] and homotaxial with those from which
Schmalhausen[629] subsequently recorded the same species. The leaves,
though smaller than many of the Indian and South African specimens of
Cordaites (Noeggerathiopsis) Hislopi, may belong to that species. Zeiller
and others definitely assigned the Russian leaves to Cordaites.
Euryphyllum. The Indian leaves for which Feistmantel[630] proposed this
name are, as several writers have pointed out, in all probability referable to
Cordaites.
The general conclusion to be drawn from this imperfect summary of an
extensive literature is that the employment of the generic names
Noeggerathiopsis, Rhiptozamites, Euryphyllum, and others has tended to
exaggerate the difference between the European and Southern botanical
provinces during the Permo-Carboniferous period.
Scale-leaves, seeds, and stems.
The occurrence of small scale-like leaves of the type represented in fig.
468, C, in association with Cordaites (Noeggerathiopsis) Hislopi[631] in
India, Brazil, Siberia, and elsewhere may mean that these organs are scales
of large foliar buds. The occurrence of several forms of platyspermic seeds,
in some cases apparently identical with European forms and sometimes
distinct types, in close association with Cordaites (Noeggerathiopsis)
Page 286
Hislopi has already been mentioned. Examples of such seeds are described
in Chapter xxxv. under the genus Samaropsis.
There are very few satisfactory examples of Cordaitean branches from
the southern hemisphere. Schmalhausen[632] figures good specimens from
Siberian rocks from which his Rhiptozamites leaves were obtained.
Branches with spirally disposed leaf-scars figured by Zeiller[633] from the
Rhaetic of Tonkin closely resemble Cordaicladus. Feistmantel’s drawing of
a fossil from the Karharbari series, compared by him with a Fern
rhizome[634], may be a Cordaitean branch, and the same author describes a
stem[635] from New South Wales as Caulopteris Adamsi which bears a close
resemblance to a branch of Cordaites. Similarly a leafy shoot described
from India by Zeiller as Araucarites Oldhami[636] may be compared with
branches of the Poa-Cordaites type.
Fig. 473. Cordaites (or Mesoxylon?) stem showing the discoid pith
partially enclosed by wood. (½ nat. size.) M. S.
Stems. i. Pith-casts.
Artisia. Sternberg.
in Chapter xxxv. under the genus Samaropsis.
There are very few satisfactory examples of Cordaitean branches from
the southern hemisphere. Schmalhausen[632] figures good specimens from
Siberian rocks from which his Rhiptozamites leaves were obtained.
Branches with spirally disposed leaf-scars figured by Zeiller[633] from the
Rhaetic of Tonkin closely resemble Cordaicladus. Feistmantel’s drawing of
a fossil from the Karharbari series, compared by him with a Fern
rhizome[634], may be a Cordaitean branch, and the same author describes a
stem[635] from New South Wales as Caulopteris Adamsi which bears a close
resemblance to a branch of Cordaites. Similarly a leafy shoot described
from India by Zeiller as Araucarites Oldhami[636] may be compared with
branches of the Poa-Cordaites type.
Fig. 473. Cordaites (or Mesoxylon?) stem showing the discoid pith
partially enclosed by wood. (½ nat. size.) M. S.
Stems. i. Pith-casts.
Artisia. Sternberg.
Page 287
A character to which authors tend to attach excessive importance as a
diagnostic feature is the almost invariable tendency of the parenchymatous
pith of Cordaites to break up on contraction into transverse diaphragms,
thus producing what is known as a discoid pith. In the stem shown in fig.
473 the pith is represented by a more or less cylindrical cast characterised
by fairly regular transverse ribs and narrow grooves; in the upper part of the
fossil the peripheral tissue of the pith is preserved in the form of narrow
plates projecting from the inner face of the wood. As Renault[637] pointed
out, this type of pith is the expression of certain conditions of growth and is
not a satisfactory distinguishing feature of any particular genus or family.
The same tendency to form a discoid pith is characteristic of Mesoxylon,
and it occurs also in some other Palaeozoic genera. Corda long ago figured
a stem attributed by him to Lomatofloyos with a typical discoid pith, and a
similar pith is recorded in a stem of Dicranophyllum[638]. Among recent
plants Juglans regia affords perhaps the most familiar instance of an
identical form of pith: the same type occurs in the white Jasmine, in
Ceropegia peltata, and some other flowering plants. An interesting case is
that of the tree Groundsel, Senecio praecox D.C.[639], of Mexico: in this
plant, which grows in arid districts, the pith serves as a water-store and as
the water is drawn off the thick turgescent discs contract and form thin
transverse diaphragms separated by wide spaces, as is also the case on
drying in some succulent Euphorbia stems. It may be that in Cordaites the
medullary region also served as a water-reservoir and the depth of the
medullary discs would vary according to the state of their contents.
The earlier writers regarded the pith-casts as stems with scars of
amplexicaul leaves: Artis[640] described specimens from the English Coal
Measures as Sternbergia, one of which he stated to be 6 ft long; a few years
later Sternberg[641] proposed the name Artisia and this has been generally
used on the ground that Sternbergia is the name of a recent flowering plant.
A specimen of Artisia transversa (Art.) from the Coal Measures of
Yorkshire is shown in fig. 466, B, and similar specimens varying
considerably in diameter up to about 10 cm. are abundant in European and
American Coal Measures. The prominence and depth of the transverse
ridges, the presence or absence of anastomoses between adjacent discs are,
as Zeiller[642] says, of very doubtful value as specific characters. Dawson in
1846[643] spoke of Artisia as probably the pith of a tree, a view suggested to
him by Mr Dawes. In 1851 Williamson[644] published a description of some
diagnostic feature is the almost invariable tendency of the parenchymatous
pith of Cordaites to break up on contraction into transverse diaphragms,
thus producing what is known as a discoid pith. In the stem shown in fig.
473 the pith is represented by a more or less cylindrical cast characterised
by fairly regular transverse ribs and narrow grooves; in the upper part of the
fossil the peripheral tissue of the pith is preserved in the form of narrow
plates projecting from the inner face of the wood. As Renault[637] pointed
out, this type of pith is the expression of certain conditions of growth and is
not a satisfactory distinguishing feature of any particular genus or family.
The same tendency to form a discoid pith is characteristic of Mesoxylon,
and it occurs also in some other Palaeozoic genera. Corda long ago figured
a stem attributed by him to Lomatofloyos with a typical discoid pith, and a
similar pith is recorded in a stem of Dicranophyllum[638]. Among recent
plants Juglans regia affords perhaps the most familiar instance of an
identical form of pith: the same type occurs in the white Jasmine, in
Ceropegia peltata, and some other flowering plants. An interesting case is
that of the tree Groundsel, Senecio praecox D.C.[639], of Mexico: in this
plant, which grows in arid districts, the pith serves as a water-store and as
the water is drawn off the thick turgescent discs contract and form thin
transverse diaphragms separated by wide spaces, as is also the case on
drying in some succulent Euphorbia stems. It may be that in Cordaites the
medullary region also served as a water-reservoir and the depth of the
medullary discs would vary according to the state of their contents.
The earlier writers regarded the pith-casts as stems with scars of
amplexicaul leaves: Artis[640] described specimens from the English Coal
Measures as Sternbergia, one of which he stated to be 6 ft long; a few years
later Sternberg[641] proposed the name Artisia and this has been generally
used on the ground that Sternbergia is the name of a recent flowering plant.
A specimen of Artisia transversa (Art.) from the Coal Measures of
Yorkshire is shown in fig. 466, B, and similar specimens varying
considerably in diameter up to about 10 cm. are abundant in European and
American Coal Measures. The prominence and depth of the transverse
ridges, the presence or absence of anastomoses between adjacent discs are,
as Zeiller[642] says, of very doubtful value as specific characters. Dawson in
1846[643] spoke of Artisia as probably the pith of a tree, a view suggested to
him by Mr Dawes. In 1851 Williamson[644] published a description of some
Page 288
specimens in which a pith-cast, Artisia approximata Lind. and Hutt., was
enclosed by wood showing very clearly Cordaitean characters. Further
demonstration of the true nature of Artisia was supplied by Grand’Eury
from St Étienne material. If the generic name Artisia is applied to all pith-
casts showing the transverse ridges and grooves like those seen in fig. 466,
B, it must be remembered that it is not safe to assume a connexion with
Cordaites or Mesoxylon. A Liassic species described by Lignier[645] from
France as Artisia alternans is quoted by authors as evidence of the
persistence of Cordaites into the Jurassic period; but in view of the fact that
the discoid type of pith is not by any means confined to Cordaites or even
to the Cordaitales the occurrence of Artisia is in itself of no great botanical
significance.
It is also true that a discoid pith is not an invariable attribute of stems
closely allied to the genus Cordaites; but if these reservations are made the
use of the generic term Artisia serves a useful purpose.
ii. Petrified stems.
Dadoxylon. Endlicher.
Palaeobotanical literature contains numerous descriptions of Palaeozoic
petrified wood occasionally enclosing an Artisia pith-cast described under
such names as Dadoxylon, Cordaioxylon, Araucarioxylon, etc., and
regarded as portions of Cordaitean stems. It is, however, certain that much
of this material belonged to stems other than those of Cordaites. Recent
research has demonstrated the insufficiency of the secondary xylem alone,
however well preserved, as a safe guide to generic position: stems identical
in the structure of the secondary xylem differ in that of the primary portion
of the stele, and it is on the characters of the latter tissues that several
genera have recently been founded. Mesoxylon affords a striking example
of the importance of the primary xylem as a distinctive feature. As
Gothan[646] points out, the species of Calamopitys recently made the type of
a new genus Eristophyton[647] would, in the absence of the primary xylem,
probably be regarded as Cordaitean. It is important to recognise the
limitations imposed by the imperfection of the material; we cannot in most
cases determine whether a specimen should be referred to Cordaites or
Mesoxylon, and while it may be described as probably Cordaitean in affinity
enclosed by wood showing very clearly Cordaitean characters. Further
demonstration of the true nature of Artisia was supplied by Grand’Eury
from St Étienne material. If the generic name Artisia is applied to all pith-
casts showing the transverse ridges and grooves like those seen in fig. 466,
B, it must be remembered that it is not safe to assume a connexion with
Cordaites or Mesoxylon. A Liassic species described by Lignier[645] from
France as Artisia alternans is quoted by authors as evidence of the
persistence of Cordaites into the Jurassic period; but in view of the fact that
the discoid type of pith is not by any means confined to Cordaites or even
to the Cordaitales the occurrence of Artisia is in itself of no great botanical
significance.
It is also true that a discoid pith is not an invariable attribute of stems
closely allied to the genus Cordaites; but if these reservations are made the
use of the generic term Artisia serves a useful purpose.
ii. Petrified stems.
Dadoxylon. Endlicher.
Palaeobotanical literature contains numerous descriptions of Palaeozoic
petrified wood occasionally enclosing an Artisia pith-cast described under
such names as Dadoxylon, Cordaioxylon, Araucarioxylon, etc., and
regarded as portions of Cordaitean stems. It is, however, certain that much
of this material belonged to stems other than those of Cordaites. Recent
research has demonstrated the insufficiency of the secondary xylem alone,
however well preserved, as a safe guide to generic position: stems identical
in the structure of the secondary xylem differ in that of the primary portion
of the stele, and it is on the characters of the latter tissues that several
genera have recently been founded. Mesoxylon affords a striking example
of the importance of the primary xylem as a distinctive feature. As
Gothan[646] points out, the species of Calamopitys recently made the type of
a new genus Eristophyton[647] would, in the absence of the primary xylem,
probably be regarded as Cordaitean. It is important to recognise the
limitations imposed by the imperfection of the material; we cannot in most
cases determine whether a specimen should be referred to Cordaites or
Mesoxylon, and while it may be described as probably Cordaitean in affinity
Page 289
there remains the possibility that some of the Palaeozoic plants with
secondary wood like that of Cordaites, if their reproductive organs were
known, would not be included in the Cordaitales. Goeppert’s species
Araucarites Tchihatcheffi, which Renault[648] quotes as Cordaites, has
recently been assigned to a new genus Mesopitys[649] because of certain
distinctive features of the primary xylem. Additional examples might be
quoted pointing to the tendency of recent and more thorough investigation
to establish the fact that the occurrence of Permo-Carboniferous wood of
the Araucarian type does not necessarily denote the existence of Cordaites.
The question of nomenclature is necessarily raised in this connexion.
In recent years it has been customary to assign Palaeozoic wood with
Araucarian pitting to the genus Dadoxylon, while wood of the same general
type from more recent strata is by many authors referred to
Araucarioxylon[650]. This arbitrary distinction based on a difference in age is
open to serious objection. Fossil wood of the Araucarian type is widely
scattered in strata ranging from Carboniferous to Jurassic periods; it also
occurs in later formations. The fact that on the one hand Araucarian plants,
as recognised by cones and foliage-shoots, are especially characteristic of
Jurassic floras and occur more rarely in Rhaetic and Triassic floras, and on
the other hand that Cordaites and its allies reached their greatest
development in Permo-Carboniferous times, renders it probable that in the
majority of cases a distinctive name based on geological age would be in
accordance with botanical differences. But we have no satisfactory data as
to the upper limits of the Cordaiteae or the lower limits of the Araucarineae:
in all probability the two families overlapped and co-existed for more than
one geological period. It is, moreover, the plants from formations where
overlapping occurred that are the most critical from a botanical standpoint.
The age-distinction is therefore at best an artificial one and may be
seriously misleading. Potonié[651] and Gothan[652] have emphasised the
desirability of adopting the name Dadoxylon for all wood of the Araucarian
type irrespective of age. If a particular specimen can be correlated definitely
with Cordaites or some other genus it should be so designated, but the
fragmentary nature of the records usually precludes this simple course. The
most logical plan is to use the name Dadoxylon for all woods with
Araucarian characters if there is no sufficient reason for employing a less
provisional term. If the evidence clearly points to the Araucarineae the
generic name Araucarioxylon should be added in parentheses after
secondary wood like that of Cordaites, if their reproductive organs were
known, would not be included in the Cordaitales. Goeppert’s species
Araucarites Tchihatcheffi, which Renault[648] quotes as Cordaites, has
recently been assigned to a new genus Mesopitys[649] because of certain
distinctive features of the primary xylem. Additional examples might be
quoted pointing to the tendency of recent and more thorough investigation
to establish the fact that the occurrence of Permo-Carboniferous wood of
the Araucarian type does not necessarily denote the existence of Cordaites.
The question of nomenclature is necessarily raised in this connexion.
In recent years it has been customary to assign Palaeozoic wood with
Araucarian pitting to the genus Dadoxylon, while wood of the same general
type from more recent strata is by many authors referred to
Araucarioxylon[650]. This arbitrary distinction based on a difference in age is
open to serious objection. Fossil wood of the Araucarian type is widely
scattered in strata ranging from Carboniferous to Jurassic periods; it also
occurs in later formations. The fact that on the one hand Araucarian plants,
as recognised by cones and foliage-shoots, are especially characteristic of
Jurassic floras and occur more rarely in Rhaetic and Triassic floras, and on
the other hand that Cordaites and its allies reached their greatest
development in Permo-Carboniferous times, renders it probable that in the
majority of cases a distinctive name based on geological age would be in
accordance with botanical differences. But we have no satisfactory data as
to the upper limits of the Cordaiteae or the lower limits of the Araucarineae:
in all probability the two families overlapped and co-existed for more than
one geological period. It is, moreover, the plants from formations where
overlapping occurred that are the most critical from a botanical standpoint.
The age-distinction is therefore at best an artificial one and may be
seriously misleading. Potonié[651] and Gothan[652] have emphasised the
desirability of adopting the name Dadoxylon for all wood of the Araucarian
type irrespective of age. If a particular specimen can be correlated definitely
with Cordaites or some other genus it should be so designated, but the
fragmentary nature of the records usually precludes this simple course. The
most logical plan is to use the name Dadoxylon for all woods with
Araucarian characters if there is no sufficient reason for employing a less
provisional term. If the evidence clearly points to the Araucarineae the
generic name Araucarioxylon should be added in parentheses after
Page 290
Dadoxylon, but whether or not this is done, a statement as to the geological
age of the fossil will in itself be some assistance in enabling the student to
form an opinion on the balance of probability in favour of a Cordaitean or
an Araucarian affinity. The course suggested by Gothan[653], namely to add
Cordaites after Dadoxylon if an Artisia pith is present, is rendered
inoperative now that we know that a discoid pith occurs in more than one
genus. In this chapter we are concerned primarily with Cordaites and with
such stems as may fairly be regarded as Cordaitean: examples of fossil
wood from later formations are dealt with in another place. A distinction
between Araucarioxylon and Cordaioxylon stems has been based by Felix
on the nature of the pith-casts; those of the Artisia type he refers to
Cordaioxylon, while Palaeozoic stems with Tylodendron pith-casts are
assigned to Araucarioxylon[654]. This distinction can, however, only be made
in the comparatively few cases in which the pith-cast is preserved. Its
validity is, moreover, open to question. A Tylodendron (= Schizodendron)
cast shows on its surface the characters of the inner face of the secondary
xylem, projecting spindle-shaped areas representing the inner ends of
medullary rays and a reticulum of grooves formed by the more resistant and
prominent inner edges of the rows of tracheids (fig. 746). A pith-cast of a
stem in which the destruction by decay of the medullary parenchyma had
not extended to the edge of the xylem-cylinder might show transverse
diaphragms. The occurrence of Tylodendron casts means that decay had
extended to the surface of the wood. But in view of the occurrence of
Tylodendron casts in stems that are not those of Cordaites a short account of
the genus is given on another page[655].
The main features of the stem of Cordaites have already been
enumerated. The stele agrees with that of Araucaria and Agathis and
especially with Agathis in the double nature of the leaf-trace. Williamson[656]
in 1877 described pieces of wood from the English Coal Measures and the
Lower Carboniferous of Scotland which he referred to Dadoxylon but
without any specific name. These include the Coalbrookdale stem in which
he had previously demonstrated the connexion between Artisia and
Dadoxylon. The structure of the xylem is like that in D. Brandlingii and the
specimens may belong to that species. The most interesting fact recorded by
Williamson is the occurrence of double leaf-traces, a feature which led him
to suspect a remote generic affinity to Ginkgo. This double trace may be an
important diagnostic feature but unfortunately the majority of descriptions
age of the fossil will in itself be some assistance in enabling the student to
form an opinion on the balance of probability in favour of a Cordaitean or
an Araucarian affinity. The course suggested by Gothan[653], namely to add
Cordaites after Dadoxylon if an Artisia pith is present, is rendered
inoperative now that we know that a discoid pith occurs in more than one
genus. In this chapter we are concerned primarily with Cordaites and with
such stems as may fairly be regarded as Cordaitean: examples of fossil
wood from later formations are dealt with in another place. A distinction
between Araucarioxylon and Cordaioxylon stems has been based by Felix
on the nature of the pith-casts; those of the Artisia type he refers to
Cordaioxylon, while Palaeozoic stems with Tylodendron pith-casts are
assigned to Araucarioxylon[654]. This distinction can, however, only be made
in the comparatively few cases in which the pith-cast is preserved. Its
validity is, moreover, open to question. A Tylodendron (= Schizodendron)
cast shows on its surface the characters of the inner face of the secondary
xylem, projecting spindle-shaped areas representing the inner ends of
medullary rays and a reticulum of grooves formed by the more resistant and
prominent inner edges of the rows of tracheids (fig. 746). A pith-cast of a
stem in which the destruction by decay of the medullary parenchyma had
not extended to the edge of the xylem-cylinder might show transverse
diaphragms. The occurrence of Tylodendron casts means that decay had
extended to the surface of the wood. But in view of the occurrence of
Tylodendron casts in stems that are not those of Cordaites a short account of
the genus is given on another page[655].
The main features of the stem of Cordaites have already been
enumerated. The stele agrees with that of Araucaria and Agathis and
especially with Agathis in the double nature of the leaf-trace. Williamson[656]
in 1877 described pieces of wood from the English Coal Measures and the
Lower Carboniferous of Scotland which he referred to Dadoxylon but
without any specific name. These include the Coalbrookdale stem in which
he had previously demonstrated the connexion between Artisia and
Dadoxylon. The structure of the xylem is like that in D. Brandlingii and the
specimens may belong to that species. The most interesting fact recorded by
Williamson is the occurrence of double leaf-traces, a feature which led him
to suspect a remote generic affinity to Ginkgo. This double trace may be an
important diagnostic feature but unfortunately the majority of descriptions
Page 291
of species of Dadoxylon throw no light on the character of the foliar
bundles.
Thomson and Allin[657] have recently pointed out that a double leaf-trace
occurs in a stem from the Permian of Kansas described by Penhallow[658] as
Pityoxylon chasense and referred to that genus because of the supposed
occurrence of resin-canals in some of the medullary rays: the canals are
apparently leaf-traces traversing broad rays in the secondary wood.
The primary xylem of Cordaites is in direct continuity with the
secondary tracheids and does not form mesarch strands as in Mesoxylon.
The pith is usually discoid. The pitting on the tracheids is a character of
special importance: while it is true to say that as a rule the number of pits
on the radial walls of a single tracheid is larger than in the Araucarineae,
this is not always the case. In Araucaria there are occasionally as many as
five rows of alternate polygonal pits (fig. 691, A) and in some Palaeozoic
Dadoxylons there are only one[659] or two rows. The very broad zone of
transitional elements at the inner edge of the xylem-cylinder is a
characteristic feature shared by the Araucarineae[660]; the spiral protoxylem-
tracheids are succeeded by scalariform elements and these, by the gradual
anastomosing of the transverse bars, pass into tracheids with multiseriate
pitting. In this broad zone we probably have a primitive feature, an epitome
in a single stem of the course of development of multiseriate from
scalariform pitting. In some Palaeozoic species with wood of the
pycnoxylic type and agreeing generally with typical Cordaites the bordered
pits are sometimes separate and circular, and opposite pits occasionally
replace the usual alternate arrangement. Another feature on which stress has
been laid is that in Cordaites the pits occupy the whole breadth of the
tracheal wall; but this, though frequently the case, is by no means a constant
feature. In Dadoxylon Newberryi[661] the pits tend to form groups, leaving
unpitted areas, as in the genus Coenoxylon[662]. In the stem of Dadoxylon
materiarum Daws. represented in fig. 475 the pits do not always cover the
whole of the tracheid-walls: this stem is also instructive as an example of
the different appearance presented by pitted tracheids according to the state
of preservation. In some places an oblique pore is well shown while in
others only the outer border of the pit is seen. Gothan[663] has described a
specimen in which some of the pits are circular and occupy only the central
area of the xylem elements: separate circular pits occur also in D. Pedroi
bundles.
Thomson and Allin[657] have recently pointed out that a double leaf-trace
occurs in a stem from the Permian of Kansas described by Penhallow[658] as
Pityoxylon chasense and referred to that genus because of the supposed
occurrence of resin-canals in some of the medullary rays: the canals are
apparently leaf-traces traversing broad rays in the secondary wood.
The primary xylem of Cordaites is in direct continuity with the
secondary tracheids and does not form mesarch strands as in Mesoxylon.
The pith is usually discoid. The pitting on the tracheids is a character of
special importance: while it is true to say that as a rule the number of pits
on the radial walls of a single tracheid is larger than in the Araucarineae,
this is not always the case. In Araucaria there are occasionally as many as
five rows of alternate polygonal pits (fig. 691, A) and in some Palaeozoic
Dadoxylons there are only one[659] or two rows. The very broad zone of
transitional elements at the inner edge of the xylem-cylinder is a
characteristic feature shared by the Araucarineae[660]; the spiral protoxylem-
tracheids are succeeded by scalariform elements and these, by the gradual
anastomosing of the transverse bars, pass into tracheids with multiseriate
pitting. In this broad zone we probably have a primitive feature, an epitome
in a single stem of the course of development of multiseriate from
scalariform pitting. In some Palaeozoic species with wood of the
pycnoxylic type and agreeing generally with typical Cordaites the bordered
pits are sometimes separate and circular, and opposite pits occasionally
replace the usual alternate arrangement. Another feature on which stress has
been laid is that in Cordaites the pits occupy the whole breadth of the
tracheal wall; but this, though frequently the case, is by no means a constant
feature. In Dadoxylon Newberryi[661] the pits tend to form groups, leaving
unpitted areas, as in the genus Coenoxylon[662]. In the stem of Dadoxylon
materiarum Daws. represented in fig. 475 the pits do not always cover the
whole of the tracheid-walls: this stem is also instructive as an example of
the different appearance presented by pitted tracheids according to the state
of preservation. In some places an oblique pore is well shown while in
others only the outer border of the pit is seen. Gothan[663] has described a
specimen in which some of the pits are circular and occupy only the central
area of the xylem elements: separate circular pits occur also in D. Pedroi
Page 292
Zeill.[664] (fig. 476). Similar departures from the normal are illustrated by
recent species of Araucarineae. The absence of a torus is another feature
shared by Dadoxylon and true Araucarian wood. Annual rings other than
incomplete and spasmodically formed rows of narrower tracheids are not as
a rule present, and in this respect also Araucaria affords a close analogy.
Thomson[665] has figured a transverse section of a root from English Coal
Measures in which rings of growth are well defined; and other instances are
recorded. In an Australian species named by Arber D. australe[666], there are
well-marked rings of growth, and this is equally the case in some Indian
wood[667] of Permo-Carboniferous age, more nearly allied to Mesoxylon than
to Cordaites, and in a Dadoxylon of similar age from South Africa. On the
other hand the statement that annual rings occur in Palaeozoic wood is often
incorrect, partial rings having been confused with regular concentric
cylinders of summer elements. Dawson and Matthew[668] described rings in
D. ouangondianum, and Goeppert and Stenzel[669], who examined the
Canadian material, refer to circles like annual rings; but Penhallow[670] states
that there is no evidence of true growth-rings.
The medullary rays are uniseriate and consist of thin parenchymatous
cells with unpitted walls; they vary considerably in depth, usually
comparatively shallow but in some cases 40 or 50 cells deep. In recent
Araucarineae the rays are generally shallower. The absence of special
receptacles, other than occasional resiniferous tracheids, for products of
secretion is a feature common to Dadoxylon and the Araucarineae. The
phloem presents no features of special interest, but our knowledge of this
tissue is comparatively meagre.
Among other examples of large Dadoxylon stems some of which no
doubt bore Cordaitean foliage—though as a rule we have insufficient
information as regards anatomical characters to enable a decision to be
made between Cordaites and Mesoxylon—reference should be made to the
imposing array of silicified trunks in the grounds of the Chemnitz
Museum[671]. These were obtained from Lower Permian strata at Hilbersdorf
near Chemnitz from beds overlain by porphyry tuff and resting on quartz
porphyry, the volcanic material which furnished the siliceous solutions.
Several large pieces of wood were found in association with stems of
Medullosa and Psaronius, leaves of Cordaites, Artisia pith-casts, and
Cardiocarpus seeds with specimens of Walchia, Gomphostrobus and other
recent species of Araucarineae. The absence of a torus is another feature
shared by Dadoxylon and true Araucarian wood. Annual rings other than
incomplete and spasmodically formed rows of narrower tracheids are not as
a rule present, and in this respect also Araucaria affords a close analogy.
Thomson[665] has figured a transverse section of a root from English Coal
Measures in which rings of growth are well defined; and other instances are
recorded. In an Australian species named by Arber D. australe[666], there are
well-marked rings of growth, and this is equally the case in some Indian
wood[667] of Permo-Carboniferous age, more nearly allied to Mesoxylon than
to Cordaites, and in a Dadoxylon of similar age from South Africa. On the
other hand the statement that annual rings occur in Palaeozoic wood is often
incorrect, partial rings having been confused with regular concentric
cylinders of summer elements. Dawson and Matthew[668] described rings in
D. ouangondianum, and Goeppert and Stenzel[669], who examined the
Canadian material, refer to circles like annual rings; but Penhallow[670] states
that there is no evidence of true growth-rings.
The medullary rays are uniseriate and consist of thin parenchymatous
cells with unpitted walls; they vary considerably in depth, usually
comparatively shallow but in some cases 40 or 50 cells deep. In recent
Araucarineae the rays are generally shallower. The absence of special
receptacles, other than occasional resiniferous tracheids, for products of
secretion is a feature common to Dadoxylon and the Araucarineae. The
phloem presents no features of special interest, but our knowledge of this
tissue is comparatively meagre.
Among other examples of large Dadoxylon stems some of which no
doubt bore Cordaitean foliage—though as a rule we have insufficient
information as regards anatomical characters to enable a decision to be
made between Cordaites and Mesoxylon—reference should be made to the
imposing array of silicified trunks in the grounds of the Chemnitz
Museum[671]. These were obtained from Lower Permian strata at Hilbersdorf
near Chemnitz from beds overlain by porphyry tuff and resting on quartz
porphyry, the volcanic material which furnished the siliceous solutions.
Several large pieces of wood were found in association with stems of
Medullosa and Psaronius, leaves of Cordaites, Artisia pith-casts, and
Cardiocarpus seeds with specimens of Walchia, Gomphostrobus and other
Page 293
plants. Sterzel describes a stem 16·5 met. long and 1·5 met. in diameter; on
the main trunk the branch-scars are scattered but on some branches there is
a tendency to a whorled arrangement. This and many other stems are
referred to Araucarioxylon (or Dadoxylon) saxonicum, a species first
described by Reichenbach as Megadendron saxonicum. In one specimen
Sterzel states that the bordered pits are generally in 1–2 rows, though rarely
in 3–4 rows, on the radial walls of the tracheids which they do not
completely cover: the medullary rays reach a depth of between 20 and 30
cells. It is noteworthy that the stem 16·5 met. long has a pith-cast of the
Tylodendron type.
Dadoxylon (Cordaites) Brandlingii (Lindley and Hutton).
1831. Pinites Brandlingii Lindley and Hutton, Foss. Flor. Vol. i. Pl. i.
1850. Araucarites Brandlingii Goeppert, Foss. Conif. p. 232, Pls. xxxix.–
xli.
1890. Cordaioxylon Brandlingii Schenk, in Schimper and Schenk, p. 853,
fig. 408.
This species was founded on ‘a fossil giant of the vegetable kingdom’
discovered at Wideopen near Newcastle in Carboniferous strata on the
estate of Mr Brandling. The stem, 72 ft long and far from complete, showed
an irregular and not a whorled distribution of branch-scars. It is noteworthy
that in D. medullaris (Goepp.)[672], a Permian species from Saxony, the
branch-scars, while for the most part irregularly scattered, in one case
showed an approach to a whorled disposition as in recent Araucarias.
Witham[673] gave a fuller account of the structure of the stem than is
included in the original description, and the species has been described by
many later authors from both Permian and Carboniferous localities. The
pith is discoid and the broad transitional region at the inner edge of the
wood is a characteristic feature[674]. Thomson[675] points out that there is a
tendency to a retention of the scalariform type of pitting in the region of the
medullary rays. There are 1–5 rows of pits on the radial walls of the
tracheids. The rays may reach a depth of 40 cells; they are usually one cell
broad. It has recently been shown that as many as six vascular strands[676]
may form one leaf-trace instead of the customary pair, a feature suggesting
comparison with Metacordaites Rigolloti Ren. with its five foliar bundles.
Other species agree very closely with D. Brandlingii and it is impossible to
determine with accuracy the precise specific limits of stems agreeing
the main trunk the branch-scars are scattered but on some branches there is
a tendency to a whorled arrangement. This and many other stems are
referred to Araucarioxylon (or Dadoxylon) saxonicum, a species first
described by Reichenbach as Megadendron saxonicum. In one specimen
Sterzel states that the bordered pits are generally in 1–2 rows, though rarely
in 3–4 rows, on the radial walls of the tracheids which they do not
completely cover: the medullary rays reach a depth of between 20 and 30
cells. It is noteworthy that the stem 16·5 met. long has a pith-cast of the
Tylodendron type.
Dadoxylon (Cordaites) Brandlingii (Lindley and Hutton).
1831. Pinites Brandlingii Lindley and Hutton, Foss. Flor. Vol. i. Pl. i.
1850. Araucarites Brandlingii Goeppert, Foss. Conif. p. 232, Pls. xxxix.–
xli.
1890. Cordaioxylon Brandlingii Schenk, in Schimper and Schenk, p. 853,
fig. 408.
This species was founded on ‘a fossil giant of the vegetable kingdom’
discovered at Wideopen near Newcastle in Carboniferous strata on the
estate of Mr Brandling. The stem, 72 ft long and far from complete, showed
an irregular and not a whorled distribution of branch-scars. It is noteworthy
that in D. medullaris (Goepp.)[672], a Permian species from Saxony, the
branch-scars, while for the most part irregularly scattered, in one case
showed an approach to a whorled disposition as in recent Araucarias.
Witham[673] gave a fuller account of the structure of the stem than is
included in the original description, and the species has been described by
many later authors from both Permian and Carboniferous localities. The
pith is discoid and the broad transitional region at the inner edge of the
wood is a characteristic feature[674]. Thomson[675] points out that there is a
tendency to a retention of the scalariform type of pitting in the region of the
medullary rays. There are 1–5 rows of pits on the radial walls of the
tracheids. The rays may reach a depth of 40 cells; they are usually one cell
broad. It has recently been shown that as many as six vascular strands[676]
may form one leaf-trace instead of the customary pair, a feature suggesting
comparison with Metacordaites Rigolloti Ren. with its five foliar bundles.
Other species agree very closely with D. Brandlingii and it is impossible to
determine with accuracy the precise specific limits of stems agreeing
Page 294
generally with this type; but for the sake of emphasising the variation in
anatomical structure it is worth while to draw attention to a few more or
less divergent forms from different geographical areas.
Dadoxylon protopityoides Felix.
An interesting feature in this Westphalian type from Germany is the
occurrence of transversely elongated pits on the tracheids[677] associated
with those of normal form closely simulating the pits in the xylem elements
of Protopitys.
Dadoxylon nummularium White.
In this Brazilian wood[678] from Permo-Carboniferous beds the medullary
rays are very numerous, mostly uniseriate and 1–30 cells in depth. The pits
on the tracheids are in 1–2 rows and are often contiguous. In another type,
D. meridionale, described by the same author[679], the pits are strictly
uniseriate and generally contiguous. As White says, the absence of the pith
and cortex and of any evidence as to the structure of the primary xylem
renders impossible any definite expression of opinion as to the affinity of
these and many other species.
Dadoxylon Nicoli Seward.
Dr Arber[680] in naming this species, from the Newcastle (Permo-
Carboniferous) Series of New South Wales, Dadoxylon australe, does not
mention Crié’s earlier account of some wood from New Caledonia under
the name Araucarioxylon australe[681]. The latter generic name according to
the usage adopted in this volume should be superseded by Dadoxylon, and
this necessitates a fresh specific name for Arber’s specimens. The name
Nicoli is suggested in place of australe, as the sections on which Arber
founded his species form part of the Nicol collection in the British Museum.
The xylem shows distinct rings of growth, a feature also seen in Indian
stems of approximately the same geological age and recorded by Shirley[682]
in wood from Queensland which needs more careful examination. The
bordered pits, usually multiseriate and contiguous, are not infrequently in
1–2 rows and separate. The uniseriate medullary rays are very numerous as
in White’s Brazilian species D. nummularium, and as a rule 6–12 cells deep.
anatomical structure it is worth while to draw attention to a few more or
less divergent forms from different geographical areas.
Dadoxylon protopityoides Felix.
An interesting feature in this Westphalian type from Germany is the
occurrence of transversely elongated pits on the tracheids[677] associated
with those of normal form closely simulating the pits in the xylem elements
of Protopitys.
Dadoxylon nummularium White.
In this Brazilian wood[678] from Permo-Carboniferous beds the medullary
rays are very numerous, mostly uniseriate and 1–30 cells in depth. The pits
on the tracheids are in 1–2 rows and are often contiguous. In another type,
D. meridionale, described by the same author[679], the pits are strictly
uniseriate and generally contiguous. As White says, the absence of the pith
and cortex and of any evidence as to the structure of the primary xylem
renders impossible any definite expression of opinion as to the affinity of
these and many other species.
Dadoxylon Nicoli Seward.
Dr Arber[680] in naming this species, from the Newcastle (Permo-
Carboniferous) Series of New South Wales, Dadoxylon australe, does not
mention Crié’s earlier account of some wood from New Caledonia under
the name Araucarioxylon australe[681]. The latter generic name according to
the usage adopted in this volume should be superseded by Dadoxylon, and
this necessitates a fresh specific name for Arber’s specimens. The name
Nicoli is suggested in place of australe, as the sections on which Arber
founded his species form part of the Nicol collection in the British Museum.
The xylem shows distinct rings of growth, a feature also seen in Indian
stems of approximately the same geological age and recorded by Shirley[682]
in wood from Queensland which needs more careful examination. The
bordered pits, usually multiseriate and contiguous, are not infrequently in
1–2 rows and separate. The uniseriate medullary rays are very numerous as
in White’s Brazilian species D. nummularium, and as a rule 6–12 cells deep.
Page 295
Some well-preserved specimens from Permo-Carboniferous strata in Natal
and Zululand have been described by Warren[683] as Dadoxylon australe
Arb., showing interesting anatomical features, but the material almost
certainly includes more than one specific type and would repay more
detailed investigation.
Dadoxylon materiarum Dawson.
This species was described by Dawson[684] from Carboniferous strata in
Nova Scotia and afterwards referred by Penhallow[685] to the genus
Cordaites. In the transverse section reproduced in fig. 474, A, the tracheid-
walls have been reduced in thickness by partial decay, but some of the
bordered pits are clearly shown on the radial walls; the pits usually form 2–
4 contiguous rows (fig. 475) in some cases with an oblique pore while
others are represented either by the outer border of the pit or by the pore
only. The narrow medullary rays are as a rule uniseriate and may be 60 cells
deep (fig. 474, B). Dawson states that some specimens have large Artisia
pith-casts, a fact that formerly would have been regarded as proof of the
Cordaites nature of the wood, but in the absence of evidence with regard to
the nature of the primary xylem it is impossible to say whether the stem is
Cordaites or Mesoxylon.
Dadoxylon sp.
Some wood received from Mr Leslie, collected at Vereeniging, South
Africa, in Permo-Carboniferous rocks, shows well-defined rings of growth.
The pits form either a single row, a double, alternate and contiguous row, or
rarely three series on the tracheid walls. The medullary rays are usually
uniseriate and 1–30 cells deep.
Dadoxylon Kayi Arber.
This species is represented by some large trunks, in some cases with a
diameter of 40 cm., discovered by Mr Kay in the Coal Measures of
Worcestershire[686]. The pith is very small and shows no indication of a
discoid structure, but owing to its poor preservation no sections could be
obtained of this region. The secondary wood is characterised by the large
number of uniseriate medullary rays 1–27 cells in depth; the tracheids have
usually two or sometimes three rows of alternate and contiguous bordered
and Zululand have been described by Warren[683] as Dadoxylon australe
Arb., showing interesting anatomical features, but the material almost
certainly includes more than one specific type and would repay more
detailed investigation.
Dadoxylon materiarum Dawson.
This species was described by Dawson[684] from Carboniferous strata in
Nova Scotia and afterwards referred by Penhallow[685] to the genus
Cordaites. In the transverse section reproduced in fig. 474, A, the tracheid-
walls have been reduced in thickness by partial decay, but some of the
bordered pits are clearly shown on the radial walls; the pits usually form 2–
4 contiguous rows (fig. 475) in some cases with an oblique pore while
others are represented either by the outer border of the pit or by the pore
only. The narrow medullary rays are as a rule uniseriate and may be 60 cells
deep (fig. 474, B). Dawson states that some specimens have large Artisia
pith-casts, a fact that formerly would have been regarded as proof of the
Cordaites nature of the wood, but in the absence of evidence with regard to
the nature of the primary xylem it is impossible to say whether the stem is
Cordaites or Mesoxylon.
Dadoxylon sp.
Some wood received from Mr Leslie, collected at Vereeniging, South
Africa, in Permo-Carboniferous rocks, shows well-defined rings of growth.
The pits form either a single row, a double, alternate and contiguous row, or
rarely three series on the tracheid walls. The medullary rays are usually
uniseriate and 1–30 cells deep.
Dadoxylon Kayi Arber.
This species is represented by some large trunks, in some cases with a
diameter of 40 cm., discovered by Mr Kay in the Coal Measures of
Worcestershire[686]. The pith is very small and shows no indication of a
discoid structure, but owing to its poor preservation no sections could be
obtained of this region. The secondary wood is characterised by the large
number of uniseriate medullary rays 1–27 cells in depth; the tracheids have
usually two or sometimes three rows of alternate and contiguous bordered
Page 296
pits on the radial walls. Arber regards the absence of a discoid pith as a fatal
objection to a reference of the stems to Cordaites and speaks of them as
affording further evidence of the occurrence of Coniferae in the higher Coal
Measures of the Midlands. It is, however, impossible to determine the
position of the species in the absence of any data with regard to the
structure of the perimedullary region, and without such information we are
hardly justified in regarding Dadoxylon Kayi as a member of the
Coniferales.
Fig. 474. Dadoxylon materiarum. Transverse (A) and tangential (B)
sections of the secondary xylem. (Kidston Coll. 222, 224.)
objection to a reference of the stems to Cordaites and speaks of them as
affording further evidence of the occurrence of Coniferae in the higher Coal
Measures of the Midlands. It is, however, impossible to determine the
position of the species in the absence of any data with regard to the
structure of the perimedullary region, and without such information we are
hardly justified in regarding Dadoxylon Kayi as a member of the
Coniferales.
Fig. 474. Dadoxylon materiarum. Transverse (A) and tangential (B)
sections of the secondary xylem. (Kidston Coll. 222, 224.)
Page 297
Fig. 475. Dadoxylon materiarum. A–C radial longitudinal sections of the
secondary xylem. (Kidston Coll. 225.)
Dadoxylon Pedroi Zeiller.
This species from Upper Carboniferous or possibly Lower Permian strata
in Brazil[687] has a pith 3·8 cm. in diameter composed of parenchyma with
scattered secretory sacs and characterised by the occurrence of three
equidistant bays projecting into the cylinder of wood (fig. 476, A) which
extend through the length of the specimen (6 cm.): these, as Zeiller
suggests, may be connected with the departure of leaf-traces or branches.
The xylem is entirely composed of centrifugal elements and shows a broad
transitional zone (fig. 476, B) including spiral, scalariform, and reticulate
tracheids, but the bordered pits are less numerous and less crowded than in
many species of Dadoxylon. The rays are 1–2 cells broad and reach a depth
of 50 cells. The most striking features are the solid and not discoid pith with
its three rounded bays and secretory canals, also the smaller number and
frequently circular form of the pits on the tracheids. Zeiller considers that
the stem is that of some Cordaitean plant though probably not a true
Cordaites. White[688] questions the advisability of adopting the generic name
Dadoxylon and suggests the possibility, though without any satisfactory
evidence, that it is the stem of a Gangamopteris. Failing further
secondary xylem. (Kidston Coll. 225.)
Dadoxylon Pedroi Zeiller.
This species from Upper Carboniferous or possibly Lower Permian strata
in Brazil[687] has a pith 3·8 cm. in diameter composed of parenchyma with
scattered secretory sacs and characterised by the occurrence of three
equidistant bays projecting into the cylinder of wood (fig. 476, A) which
extend through the length of the specimen (6 cm.): these, as Zeiller
suggests, may be connected with the departure of leaf-traces or branches.
The xylem is entirely composed of centrifugal elements and shows a broad
transitional zone (fig. 476, B) including spiral, scalariform, and reticulate
tracheids, but the bordered pits are less numerous and less crowded than in
many species of Dadoxylon. The rays are 1–2 cells broad and reach a depth
of 50 cells. The most striking features are the solid and not discoid pith with
its three rounded bays and secretory canals, also the smaller number and
frequently circular form of the pits on the tracheids. Zeiller considers that
the stem is that of some Cordaitean plant though probably not a true
Cordaites. White[688] questions the advisability of adopting the generic name
Dadoxylon and suggests the possibility, though without any satisfactory
evidence, that it is the stem of a Gangamopteris. Failing further
Page 298
information, there would seem to be no sufficient reason for the institution
of a distinctive generic name.
Fig. 476. Dadoxylon Pedroi. A, transverse section showing the pith and
part of the secondary wood. B, longitudinal section of part of the
secondary wood. (After Zeiller.)
Dadoxylon permiense (Renault).
This Permian species from Autun[689] differs from typical examples of the
genus in the differentiation of the pith into a central thin-walled region
contracted into transverse diaphragms surrounded by a cylinder of stouter
of a distinctive generic name.
Fig. 476. Dadoxylon Pedroi. A, transverse section showing the pith and
part of the secondary wood. B, longitudinal section of part of the
secondary wood. (After Zeiller.)
Dadoxylon permiense (Renault).
This Permian species from Autun[689] differs from typical examples of the
genus in the differentiation of the pith into a central thin-walled region
contracted into transverse diaphragms surrounded by a cylinder of stouter
Page 299
tissue and in the greater breadth of the medullary rays. The tracheids have
3–4 rows of pits of the usual type. Spirally disposed, decurrent, leaf-bases
occur on the surface of the stem, and the cortex includes secretory canals
and strands of hypodermal stereome. A small number of veins pass up the
median part of the lamina which in this respect and in its greater thickness
differs from that of Cordaites leaves. Renault speaks of the rays as a
cycadean feature, but they are only two cells in width and shorter than in
recent Cycads.
Dadoxylon spetsbergense Gothan.
In this species[690] from Spitzbergen, of doubtful age though probably
Palaeozoic, there is no xylem-parenchyma and the medullary rays are from
2 to 5 cells deep; the bordered pits occur in 1–2 or rarely 3 rows on the
radial walls of the tracheids; they are alternate but not flattened and
characterised by their small size (7μ high); they do not cover the whole face
of the tracheids. It is pointed out that in many Palaeozoic and Mesozoic
Dadoxylons the pits are larger than in recent species (16–17·5μ as
compared with 9–12μ) while in D. spetsbergense they are still smaller. The
large size of the medullary-ray cells is another noteworthy feature, also the
absence of annual rings, a character possibly connected with conditions of
growth in northern regions. It is, however, pointed out by Nathorst[691] that
the fossil was not found in situ and, as he says, it may have been carried by
currents from a more southern locality.
Metacordaites. Renault.
Metacordaites Rigolloti Renault.
Renault founded this species[692] and genus on a stem from Autun which,
like D. Pedroi, differs in certain respects from stems usually attributed to
Cordaites. The pith is solid and contains secretory ducts and cells; the
tracheids have often a single row of pits, and multiseriate pitting is much
less common than in Dadoxylon. The medullary rays are generally 1–6 cells
deep. A striking feature is the occurrence of groups of five vascular bundles
penetrating the secondary wood in [Symbol: V]-shaped groups, each group
being regarded as a multiple leaf-trace, a type recently recognised by
Thomson in D. Brandlingii. In one of Renault’s figures a larger scar,
3–4 rows of pits of the usual type. Spirally disposed, decurrent, leaf-bases
occur on the surface of the stem, and the cortex includes secretory canals
and strands of hypodermal stereome. A small number of veins pass up the
median part of the lamina which in this respect and in its greater thickness
differs from that of Cordaites leaves. Renault speaks of the rays as a
cycadean feature, but they are only two cells in width and shorter than in
recent Cycads.
Dadoxylon spetsbergense Gothan.
In this species[690] from Spitzbergen, of doubtful age though probably
Palaeozoic, there is no xylem-parenchyma and the medullary rays are from
2 to 5 cells deep; the bordered pits occur in 1–2 or rarely 3 rows on the
radial walls of the tracheids; they are alternate but not flattened and
characterised by their small size (7μ high); they do not cover the whole face
of the tracheids. It is pointed out that in many Palaeozoic and Mesozoic
Dadoxylons the pits are larger than in recent species (16–17·5μ as
compared with 9–12μ) while in D. spetsbergense they are still smaller. The
large size of the medullary-ray cells is another noteworthy feature, also the
absence of annual rings, a character possibly connected with conditions of
growth in northern regions. It is, however, pointed out by Nathorst[691] that
the fossil was not found in situ and, as he says, it may have been carried by
currents from a more southern locality.
Metacordaites. Renault.
Metacordaites Rigolloti Renault.
Renault founded this species[692] and genus on a stem from Autun which,
like D. Pedroi, differs in certain respects from stems usually attributed to
Cordaites. The pith is solid and contains secretory ducts and cells; the
tracheids have often a single row of pits, and multiseriate pitting is much
less common than in Dadoxylon. The medullary rays are generally 1–6 cells
deep. A striking feature is the occurrence of groups of five vascular bundles
penetrating the secondary wood in [Symbol: V]-shaped groups, each group
being regarded as a multiple leaf-trace, a type recently recognised by
Thomson in D. Brandlingii. In one of Renault’s figures a larger scar,
Page 300
presumably a branch-scar, is shown immediately above a group of foliar
bundles. The genus Metacordaites is considered by its author to be
intermediate between Conifers and the Cordaitales, but nearer to the former.
This conclusion is, however, based on insufficient evidence, as nothing is
known of the reproductive organs.
Roots.
In 1871 Williamson[693] gave an account of a petrified plant from the
Lancashire Coal Measures which he named Dictyoxylon radicans, but he
afterwards came to the conclusion that the specimens so named were
portions of the subterranean axis of some other plant, possibly
Asterophyllites, and proposed a new generic term Amyelon[694]. In 1874 he
brought forward fresh evidence in support of connecting Amyelon radicans
with Asterophyllites or Sphenophyllum, genera which Williamson believed
to be very closely related. It has since been recognised that Amyelon is the
root of Cordaites or of some closely allied member of the Cordaitales. Our
knowledge of Cordaitean roots is based chiefly on the work of Williamson
and Renault[695], and more recently Osborne[696] has added new facts of
considerable interest. In the larger roots the primary xylem may be diarch or
there may be as many as four or five protoxylem groups (fig. 477). The
primary tracheids are spiral or scalariform and the space, s, separating them
from the surrounding secondary xylem seen in fig. 477, B, was no doubt
originally occupied by conjunctive parenchyma. The secondary wood is
composed of tracheids, with contiguous bordered pits identical with those in
the xylem of the stem, and narrow medullary rays. The section, 4 mm. in
diameter, represented in fig. 477, A, shows a tetrarch primary xylem strand
enclosed by secondary wood composed of rather thin-walled elements
succeeded by a zone of phloem including some secretory sacs, and beyond
this is a cylinder of periderm, p. In a section of a root figured by Renault
from Autun the periderm is separated from the stele by a broad band of
parenchyma which appears to be cortical, but in the British specimens the
deep-seated origin of the periderm is clearly shown: Osborne states that it
arises in a layer immediately outside the endodermis. In one of the
specimens figured by Williamson[697] the secondary wood shows clearly
marked irregular concentric lines simulating rings of growth, but there is no
evidence of any regularly recurring variation in the diameter of the xylem-
bundles. The genus Metacordaites is considered by its author to be
intermediate between Conifers and the Cordaitales, but nearer to the former.
This conclusion is, however, based on insufficient evidence, as nothing is
known of the reproductive organs.
Roots.
In 1871 Williamson[693] gave an account of a petrified plant from the
Lancashire Coal Measures which he named Dictyoxylon radicans, but he
afterwards came to the conclusion that the specimens so named were
portions of the subterranean axis of some other plant, possibly
Asterophyllites, and proposed a new generic term Amyelon[694]. In 1874 he
brought forward fresh evidence in support of connecting Amyelon radicans
with Asterophyllites or Sphenophyllum, genera which Williamson believed
to be very closely related. It has since been recognised that Amyelon is the
root of Cordaites or of some closely allied member of the Cordaitales. Our
knowledge of Cordaitean roots is based chiefly on the work of Williamson
and Renault[695], and more recently Osborne[696] has added new facts of
considerable interest. In the larger roots the primary xylem may be diarch or
there may be as many as four or five protoxylem groups (fig. 477). The
primary tracheids are spiral or scalariform and the space, s, separating them
from the surrounding secondary xylem seen in fig. 477, B, was no doubt
originally occupied by conjunctive parenchyma. The secondary wood is
composed of tracheids, with contiguous bordered pits identical with those in
the xylem of the stem, and narrow medullary rays. The section, 4 mm. in
diameter, represented in fig. 477, A, shows a tetrarch primary xylem strand
enclosed by secondary wood composed of rather thin-walled elements
succeeded by a zone of phloem including some secretory sacs, and beyond
this is a cylinder of periderm, p. In a section of a root figured by Renault
from Autun the periderm is separated from the stele by a broad band of
parenchyma which appears to be cortical, but in the British specimens the
deep-seated origin of the periderm is clearly shown: Osborne states that it
arises in a layer immediately outside the endodermis. In one of the
specimens figured by Williamson[697] the secondary wood shows clearly
marked irregular concentric lines simulating rings of growth, but there is no
evidence of any regularly recurring variation in the diameter of the xylem-
Page 301
elements. From the descriptions of Williamson and Osborne it is evident
that the roots of Cordaites were profusely branched and, as the latter author
has shown, the method of branching points to the formation of coralline
roots like those of recent Cycads, some Conifers and Dicotyledons.
Osborne found that the cortex of small rootlets is composed of two zones,
an outer parenchyma without cell-contents and an inner parenchymatous
tissue characterised by the occurrence in some of the cells of tangled
masses of fungal hyphae almost always unseptate. In some cases the hyphae
bear terminal vesicles similar to those observed on fungal hyphae in the
cortex of Podocarpus roots. Osborne makes out a good case for regarding
the fungus as symbiotically related to the tissues of the lateral roots, a
relationship identical with that in many existing trees, particularly Myrica
and Alnus. It is suggested that the formation of the coralline root-tubercles
is a feature consistent with the view that Cordaites lived in saline marshes,
a physiologically dry habitat favourable to the occurrence of mycorhiza.
that the roots of Cordaites were profusely branched and, as the latter author
has shown, the method of branching points to the formation of coralline
roots like those of recent Cycads, some Conifers and Dicotyledons.
Osborne found that the cortex of small rootlets is composed of two zones,
an outer parenchyma without cell-contents and an inner parenchymatous
tissue characterised by the occurrence in some of the cells of tangled
masses of fungal hyphae almost always unseptate. In some cases the hyphae
bear terminal vesicles similar to those observed on fungal hyphae in the
cortex of Podocarpus roots. Osborne makes out a good case for regarding
the fungus as symbiotically related to the tissues of the lateral roots, a
relationship identical with that in many existing trees, particularly Myrica
and Alnus. It is suggested that the formation of the coralline root-tubercles
is a feature consistent with the view that Cordaites lived in saline marshes,
a physiologically dry habitat favourable to the occurrence of mycorhiza.
Page 302
Fig. 477. A, root of Cordaites. B, centre of the root enlarged; p,
periderm; s, space. (Kidston Coll. 1906.)
periderm; s, space. (Kidston Coll. 1906.)
Page 303
Fig. 478. Root (Cordaites?) exposed in the bed of the Vaal river. (After
Mellor and Leslie.)
Reference has already been made to the habit of Cordaitean roots in the
general account of the genus (figs. 468, A, 478). The specimen shown in
fig. 478 may be a root of Cordaites (Noeggerathiopsis) Hislopi, but nothing
is known as to its structure[698].
Reproductive Organs.
Cordaianthus. Grand’Eury.
We have as yet no definite knowledge of the nature of the reproductive
organs of Mesoxylon and Poroxylon, but having regard to their close
resemblance in other respects to Cordaites, particularly in the case of
Mesoxylon, the presumption is that some of the seeds and fertile shoots
attributed to Cordaites may belong to other members of the Cordaitales.
Despite the abundance of Cordaites, or at least of material assigned to that
genus, and the comparative frequency of fertile shoots in actual connexion
with foliage-shoots, the practical identity of Mesoxylon and Cordaites
leaves precludes any confident use of the latter name in a strict sense.
Mellor and Leslie.)
Reference has already been made to the habit of Cordaitean roots in the
general account of the genus (figs. 468, A, 478). The specimen shown in
fig. 478 may be a root of Cordaites (Noeggerathiopsis) Hislopi, but nothing
is known as to its structure[698].
Reproductive Organs.
Cordaianthus. Grand’Eury.
We have as yet no definite knowledge of the nature of the reproductive
organs of Mesoxylon and Poroxylon, but having regard to their close
resemblance in other respects to Cordaites, particularly in the case of
Mesoxylon, the presumption is that some of the seeds and fertile shoots
attributed to Cordaites may belong to other members of the Cordaitales.
Despite the abundance of Cordaites, or at least of material assigned to that
genus, and the comparative frequency of fertile shoots in actual connexion
with foliage-shoots, the practical identity of Mesoxylon and Cordaites
leaves precludes any confident use of the latter name in a strict sense.
Page 304
In 1822 Brongniart[699] described a small bud-like fossil
of Tertiary age as Antholithes liliacea, and this generic
name in the form Antholithus became widely used for
fertile shoots or flowers from different geological
horizons. As knowledge became more precise other
names replaced Antholithus, though Renault[700] retained it
for some inflorescences from Commentry which could not
definitely be included in Cordaites. Lindley and
Hutton[701] employed the genus for a specimen, now
recognised as a Cordaitean fertile shoot, from the Coal
Measures which they called Antholithus Pitcairniae, the
specific name being chosen to indicate a possible affinity
to the Bromeliaceous genus Pitcairnia. A few years later
Morris[702] described a similar inflorescence as A.
anomalus. In 1872 Carruthers[703] substituted Brongniart’s
term Cardiocarpon for Antholithus and called A.
Pitcairniae Cardiocarpon Lindleyi and Morris’s species
C. anomalum. The specific name Lindleyi has been widely
adopted, but there would seem to be no adequate reason
for disregarding the priority-rule. It is, however,
customary to use Grand’Eury’s term Cordaianthus for all
Cordaitean inflorescences. Goeppert[704] suggested the
name Botryoconus for an inflorescence similar to C.
Pitcairniae and for this C. E. Weiss[705] substituted
Noeggerathianthus on the ground that he considered
Goeppert’s specimen to be the male inflorescence of
Noeggerathia. Grand’Eury resuscitated Botryoconus[706]
for some spikes from the Gard coalfield connected by him
with Dory-Cordaites. The nature of the seeds borne by the Fig. 479.
inflorescences has largely influenced authors in the choice Cordaian
of a generic name: Carruthers used Cardiocarpon while thus.
[707]
Zeiller speaks of Samaropsis Pitcairniae. The genus From the
Cardiocarpon was founded by Brongniart for compressed Middle
cordiform seeds, but it was not until later that their Coal
gymnospermous nature was recognised. Further reference Measures
to the nomenclature of seeds of the Cardiocarpon type of
will be found in Chapter xxxv. The correlation by Lancashi
of Tertiary age as Antholithes liliacea, and this generic
name in the form Antholithus became widely used for
fertile shoots or flowers from different geological
horizons. As knowledge became more precise other
names replaced Antholithus, though Renault[700] retained it
for some inflorescences from Commentry which could not
definitely be included in Cordaites. Lindley and
Hutton[701] employed the genus for a specimen, now
recognised as a Cordaitean fertile shoot, from the Coal
Measures which they called Antholithus Pitcairniae, the
specific name being chosen to indicate a possible affinity
to the Bromeliaceous genus Pitcairnia. A few years later
Morris[702] described a similar inflorescence as A.
anomalus. In 1872 Carruthers[703] substituted Brongniart’s
term Cardiocarpon for Antholithus and called A.
Pitcairniae Cardiocarpon Lindleyi and Morris’s species
C. anomalum. The specific name Lindleyi has been widely
adopted, but there would seem to be no adequate reason
for disregarding the priority-rule. It is, however,
customary to use Grand’Eury’s term Cordaianthus for all
Cordaitean inflorescences. Goeppert[704] suggested the
name Botryoconus for an inflorescence similar to C.
Pitcairniae and for this C. E. Weiss[705] substituted
Noeggerathianthus on the ground that he considered
Goeppert’s specimen to be the male inflorescence of
Noeggerathia. Grand’Eury resuscitated Botryoconus[706]
for some spikes from the Gard coalfield connected by him
with Dory-Cordaites. The nature of the seeds borne by the Fig. 479.
inflorescences has largely influenced authors in the choice Cordaian
of a generic name: Carruthers used Cardiocarpon while thus.
[707]
Zeiller speaks of Samaropsis Pitcairniae. The genus From the
Cardiocarpon was founded by Brongniart for compressed Middle
cordiform seeds, but it was not until later that their Coal
gymnospermous nature was recognised. Further reference Measures
to the nomenclature of seeds of the Cardiocarpon type of
will be found in Chapter xxxv. The correlation by Lancashi
Page 305
Grand’Eury and other authors of different species of re.
inflorescences and species of Cordaites is frequently (Manche
based on association, and in the absence of more ster
satisfactory evidence the safer course is to deal with Museum;
Cordaitean fertile shoots in a general sense. ⅓ nat.
(a) Ovulate shoots. These are represented by a size.)
considerable number of forms in both European and American localities. In
rare cases the compound shoot reaches a length of 30 cm. (fig. 479), but it
is usually much shorter; the lateral compact buds may be more or less
widely separated: the seeds have long pedicels (fig. 480, A) or appear to be
sessile (fig. 480, B) and there may be one or several seeds on a single lateral
shoot. The seeds are platyspermic and, as seen in fig. 480, A, in some
inflorescences they show very clearly the Samaropsis features. It would,
however, be unsafe to assume that all Samaropsis seeds were borne on
Cordaitean plants. Among other types of seed referred by authors to
Cordaites are Cardiocarpus, Cordaicarpus, Sarcotaxus, Taxospermum,
Diplotesta, and Leptocaryon. But in most cases there is no evidence of
actual connexion between seeds and vegetative organs, and while it is
possible to state with confidence that many of the seeds represented by
impressions described as species of Samaropsis and Cordaicarpus are
undoubtedly Cordaitean, it is certain that not all seeds referable to these
genera were borne by Cordaitalean plants. Cordaitean seeds are
characterised by certain morphological features recalling those found in
recent Cycads and in the seeds of Ginkgo as illustrated by species of
Cardiocarpus and some allied types. As most of the Palaeozoic seeds
known in a petrified state cannot be assigned to their parent-plants they are
dealt with in a separate chapter[708].
Cordaianthus Pitcairniae (Lindley and Hutton).
This type of inflorescence[709] is considered by Kidston to belong to the
tree which bore leaves known as Cordaites principalis, but if this is the case
it is probable that the stem possessed the anatomical characters of
Mesoxylon.
inflorescences and species of Cordaites is frequently (Manche
based on association, and in the absence of more ster
satisfactory evidence the safer course is to deal with Museum;
Cordaitean fertile shoots in a general sense. ⅓ nat.
(a) Ovulate shoots. These are represented by a size.)
considerable number of forms in both European and American localities. In
rare cases the compound shoot reaches a length of 30 cm. (fig. 479), but it
is usually much shorter; the lateral compact buds may be more or less
widely separated: the seeds have long pedicels (fig. 480, A) or appear to be
sessile (fig. 480, B) and there may be one or several seeds on a single lateral
shoot. The seeds are platyspermic and, as seen in fig. 480, A, in some
inflorescences they show very clearly the Samaropsis features. It would,
however, be unsafe to assume that all Samaropsis seeds were borne on
Cordaitean plants. Among other types of seed referred by authors to
Cordaites are Cardiocarpus, Cordaicarpus, Sarcotaxus, Taxospermum,
Diplotesta, and Leptocaryon. But in most cases there is no evidence of
actual connexion between seeds and vegetative organs, and while it is
possible to state with confidence that many of the seeds represented by
impressions described as species of Samaropsis and Cordaicarpus are
undoubtedly Cordaitean, it is certain that not all seeds referable to these
genera were borne by Cordaitalean plants. Cordaitean seeds are
characterised by certain morphological features recalling those found in
recent Cycads and in the seeds of Ginkgo as illustrated by species of
Cardiocarpus and some allied types. As most of the Palaeozoic seeds
known in a petrified state cannot be assigned to their parent-plants they are
dealt with in a separate chapter[708].
Cordaianthus Pitcairniae (Lindley and Hutton).
This type of inflorescence[709] is considered by Kidston to belong to the
tree which bore leaves known as Cordaites principalis, but if this is the case
it is probable that the stem possessed the anatomical characters of
Mesoxylon.
Page 306
Fig. 480. A, Cordaianthus Pitcairniae with Samaropsis seeds. B,
Cordaianthus Volkmanni. B′, portion of B enlarged. (A, B, nat. size;
Kidston Coll. 2374, 1174.)
The portion of an inflorescence shown in fig. 480, A, from the Middle
Coal Measures of Yorkshire, illustrates the occurrence of the bud-like fertile
shoots and the stalked Samaropsis seeds. A species described by Renault[710]
from Commentry as Cordaianthus acicularis may be identical with the
British species.
Cordaianthus Volkmanni Ettingshausen.
The example of this species[711] seen in fig. 480, B, shows the relatively
small size of the lateral buds, presumably unexpanded, compared with the
large subtending bracts.
Petrified specimens of Cordaianthus.
Our knowledge of the structure of Cordaianthus is based on the
researches of Renault[712], supplemented by those of Prof. Bertrand[713] to
whose kindness I owe the photographs reproduced in fig. 481. The
Cordaianthus Volkmanni. B′, portion of B enlarged. (A, B, nat. size;
Kidston Coll. 2374, 1174.)
The portion of an inflorescence shown in fig. 480, A, from the Middle
Coal Measures of Yorkshire, illustrates the occurrence of the bud-like fertile
shoots and the stalked Samaropsis seeds. A species described by Renault[710]
from Commentry as Cordaianthus acicularis may be identical with the
British species.
Cordaianthus Volkmanni Ettingshausen.
The example of this species[711] seen in fig. 480, B, shows the relatively
small size of the lateral buds, presumably unexpanded, compared with the
large subtending bracts.
Petrified specimens of Cordaianthus.
Our knowledge of the structure of Cordaianthus is based on the
researches of Renault[712], supplemented by those of Prof. Bertrand[713] to
whose kindness I owe the photographs reproduced in fig. 481. The
Page 307
inflorescences described by Renault are referred by him to different species,
but in the following brief account these are treated from a generic
standpoint. The tangential section of Cordaianthus Williamsoni Ren. shown
in fig. 481, D, was originally figured by Renault and more recently by
Bertrand; it shows the spirally disposed leaf-traces in the lower part of a
stout axis, and at the sides some vascular bundles are seen passing up into
the bracts. A very small proportion of the bracts subtend ovules; two are
seen at a and b, and at c is the tangentially cut micropylar canal of a third
borne near the apex and covered by the terminal cluster of bracts. The ovule
a, separated by a narrow space from its short stalk, consists of a thick single
integument—not two as stated by Renault—extended at the apex as a
micropylar canal: the apical extension is more completely shown in the
tangentially cut ovule b. The central body is much contracted and the two
spaces, s, at the base are regarded by Bertrand as cavities in the integument
separated from one another by a central strand of conducting tissue which
gives off two bundles to the integument, one at each end of the long axis of
the seed (fig. 481, A, v). The dark patch, n (fig. D), is the upper and broader
end of the shrunken nucellus the apex of which extends upwards as a
slender beak, and this originally no doubt fitted into the micropyle. Fig.
481, C, shows a female inflorescence in transverse section; the stele
consists of a ring of bundles separated by broad medullary rays and
enclosing a comparatively large pith: the leaf-traces are seen in the cortex
and one is cut through as it bends out into a bract which is not yet free from
the axis. Two ovules, seen in section at a and b, are represented by the
bilaterally symmetrical and compressed integument enclosing small pieces
of nucellar tissue. Fig. 481, E, is a transverse section of an inflorescence at
a higher level and above the apex of the axis: there are four large ovules and
one aborted ovule, a. Bertrand describes two vascular bundles in the
integument of the ovule a, one at each end of the long axis.
but in the following brief account these are treated from a generic
standpoint. The tangential section of Cordaianthus Williamsoni Ren. shown
in fig. 481, D, was originally figured by Renault and more recently by
Bertrand; it shows the spirally disposed leaf-traces in the lower part of a
stout axis, and at the sides some vascular bundles are seen passing up into
the bracts. A very small proportion of the bracts subtend ovules; two are
seen at a and b, and at c is the tangentially cut micropylar canal of a third
borne near the apex and covered by the terminal cluster of bracts. The ovule
a, separated by a narrow space from its short stalk, consists of a thick single
integument—not two as stated by Renault—extended at the apex as a
micropylar canal: the apical extension is more completely shown in the
tangentially cut ovule b. The central body is much contracted and the two
spaces, s, at the base are regarded by Bertrand as cavities in the integument
separated from one another by a central strand of conducting tissue which
gives off two bundles to the integument, one at each end of the long axis of
the seed (fig. 481, A, v). The dark patch, n (fig. D), is the upper and broader
end of the shrunken nucellus the apex of which extends upwards as a
slender beak, and this originally no doubt fitted into the micropyle. Fig.
481, C, shows a female inflorescence in transverse section; the stele
consists of a ring of bundles separated by broad medullary rays and
enclosing a comparatively large pith: the leaf-traces are seen in the cortex
and one is cut through as it bends out into a bract which is not yet free from
the axis. Two ovules, seen in section at a and b, are represented by the
bilaterally symmetrical and compressed integument enclosing small pieces
of nucellar tissue. Fig. 481, E, is a transverse section of an inflorescence at
a higher level and above the apex of the axis: there are four large ovules and
one aborted ovule, a. Bertrand describes two vascular bundles in the
integument of the ovule a, one at each end of the long axis.
Page 308
Fig. 481. A, B, Cordaianthus Grand’Euryi, ovule showing apex of
nucellus, B, with microspores, p; pc, pollen-chamber; b, beak of
nucellus; v, vascular bundle. C, transverse section of flower-bud
with ovules, a, b. D, Cordaianthus Williamsoni, longitudinal
section; a–c ovules; s, spaces; n, nucellus. E, Cordaianthus Zeilleri,
transverse section showing four large ovules and one aborted ovule
(a); v, vascular bundle. F, transverse section of male flower; m,
microsporangia. (From photographs supplied by Prof. Bertrand.)
nucellus, B, with microspores, p; pc, pollen-chamber; b, beak of
nucellus; v, vascular bundle. C, transverse section of flower-bud
with ovules, a, b. D, Cordaianthus Williamsoni, longitudinal
section; a–c ovules; s, spaces; n, nucellus. E, Cordaianthus Zeilleri,
transverse section showing four large ovules and one aborted ovule
(a); v, vascular bundle. F, transverse section of male flower; m,
microsporangia. (From photographs supplied by Prof. Bertrand.)
Page 309
Fig. 481, A, B, Cordaianthus Grand’Euryi Ren., shows a longitudinal
section of the nucellus, 1·5 × ·7 mm., and part of the integument of an
ovule at the time of pollination, which was probably aided by the secretion
of a drop of mucilage as in the ovules of recent Conifers. The integument,
separated by a broad space from the nucellus, is cut in the plane of the two
vascular strands, v. From the centre of its broad upper surface the nucellus
projects upwards as a beak, b, and this originally engaged with the
micropylar canal formed by the integument: the lighter patch below the
beak is the pollen-chamber (fig. 481, B, pc) containing two microspores,
and two more, p, are seen above the nucellar beak. In another species
described by Renault, C. Lacattii, the nucellus fills the space bounded by
the integument.
(b) Staminate inflorescences. The male inflorescence, though smaller, is
similar in habit to the ovulate shoot: the secondary branch consists of a
short axis bearing crowded, spirally disposed, bracts, and the actual flowers
are represented by single stamens or groups of 2–3 highly specialised
microsporophylls. Each microsporophyll consists of a long filament with a
central vascular strand bearing at its apex 3–4 long microsporangia (fig.
481, F, m) which open longitudinally as seen in fig. 482, A. The
microsporangia are 2·5–3 mm. long covered by dark palisade cells and thin-
walled parenchyma, shown as indistinct patches in the photograph. Some of
the elliptical and comparatively large microspores are seen in fig. 482, B;
the exine is finely punctate and inside are the remains of a few thin cells in
which presumably spermatozoids were developed. The microspores shown
in fig. 482, B, have a maximum length of 0·1 mm.: Renault describes some
as 0·9 mm. long while others are much smaller. Fig. 481, F, is a transverse
section of a staminate inflorescence showing near the centre five groups of
microsporangia, each sporangium having the form of a curved incomplete
dark band indicating that dehiscence has occurred.
section of the nucellus, 1·5 × ·7 mm., and part of the integument of an
ovule at the time of pollination, which was probably aided by the secretion
of a drop of mucilage as in the ovules of recent Conifers. The integument,
separated by a broad space from the nucellus, is cut in the plane of the two
vascular strands, v. From the centre of its broad upper surface the nucellus
projects upwards as a beak, b, and this originally engaged with the
micropylar canal formed by the integument: the lighter patch below the
beak is the pollen-chamber (fig. 481, B, pc) containing two microspores,
and two more, p, are seen above the nucellar beak. In another species
described by Renault, C. Lacattii, the nucellus fills the space bounded by
the integument.
(b) Staminate inflorescences. The male inflorescence, though smaller, is
similar in habit to the ovulate shoot: the secondary branch consists of a
short axis bearing crowded, spirally disposed, bracts, and the actual flowers
are represented by single stamens or groups of 2–3 highly specialised
microsporophylls. Each microsporophyll consists of a long filament with a
central vascular strand bearing at its apex 3–4 long microsporangia (fig.
481, F, m) which open longitudinally as seen in fig. 482, A. The
microsporangia are 2·5–3 mm. long covered by dark palisade cells and thin-
walled parenchyma, shown as indistinct patches in the photograph. Some of
the elliptical and comparatively large microspores are seen in fig. 482, B;
the exine is finely punctate and inside are the remains of a few thin cells in
which presumably spermatozoids were developed. The microspores shown
in fig. 482, B, have a maximum length of 0·1 mm.: Renault describes some
as 0·9 mm. long while others are much smaller. Fig. 481, F, is a transverse
section of a staminate inflorescence showing near the centre five groups of
microsporangia, each sporangium having the form of a curved incomplete
dark band indicating that dehiscence has occurred.
Page 310
Fig. 482. Cordaianthus. Microsporangia, A, and Microspores, B.
(University College Collection, London.)
Mesoxylon. Scott and Maslen.
This generic name was instituted for stems obtained by Messrs Lomax
from the Lower Coal Measures of Lancashire[714] previously referred by
Scott[715] to Cordaites and Poroxylon. Further investigation showed that
while agreeing closely with those genera they possessed certain distinctive
features demanding recognition. The name chosen suggests the intermediate
nature of the stems. The more striking features may be summarised as
follows: In the largest specimens so far described the stem, including leaf-
bases, reaches a diameter of 5 or 6 cm.; the large pith consists in the central
region of diaphragms of parenchyma separated by horizontal spaces
produced by splitting and shrinkage consequent on the failure of the tissue
to keep pace with the general growth of the stem. The secondary xylem is
of the Araucarian type and has narrow medullary rays varying in depth from
1 to 25 cells. The leaf-traces are represented by twin-bundles which fuse in
the downward direction, the level at which fusion occurs being regarded as
a specific character. The presence of centripetal xylem is an essential
(University College Collection, London.)
Mesoxylon. Scott and Maslen.
This generic name was instituted for stems obtained by Messrs Lomax
from the Lower Coal Measures of Lancashire[714] previously referred by
Scott[715] to Cordaites and Poroxylon. Further investigation showed that
while agreeing closely with those genera they possessed certain distinctive
features demanding recognition. The name chosen suggests the intermediate
nature of the stems. The more striking features may be summarised as
follows: In the largest specimens so far described the stem, including leaf-
bases, reaches a diameter of 5 or 6 cm.; the large pith consists in the central
region of diaphragms of parenchyma separated by horizontal spaces
produced by splitting and shrinkage consequent on the failure of the tissue
to keep pace with the general growth of the stem. The secondary xylem is
of the Araucarian type and has narrow medullary rays varying in depth from
1 to 25 cells. The leaf-traces are represented by twin-bundles which fuse in
the downward direction, the level at which fusion occurs being regarded as
a specific character. The presence of centripetal xylem is an essential
Page 311
feature of the traces: the occurrence of single or double traces consisting of
centripetal elements and, externally, a large amount of centrifugal xylem is
an important feature in which Mesoxylon differs from Cordaites. The
double leaf-traces divide after emerging from the secondary wood and each
strap-like leaf receives several collateral bundles (fig. 483, C). An axillary
bud may occur at the base of each leaf (fig. 483, A, b). The phloem,
including sieve-tubes and secretory sacs, is succeeded by a broad pericycle,
and the comparatively narrow cortex is traversed by successive bands of
periderm. In the outer region of the cortex the presence of radial bands of
fibres is a characteristic feature. The reproductive organs are unknown. The
anatomical features are well illustrated by M. Sutcliffii first described by
Scott, who provisionally placed it in Poroxylon, and afterwards more fully
investigated by Maslen[716].
Mesoxylon Sutcliffii Scott.
The average diameter of the stem is 3 cm.: the section reproduced in fig.
483, A, has a maximum breadth of 3·5 cm.; the leaf-bases cut at different
levels give an irregular contour to the surface like that of a Lepidodendron.
An axillary bud, either reproductive or vegetative, is seen at b consisting of
a short axis bearing crowded bud-scales. The leaves are crowded and
according to Maslen have a phyllotaxis of ⁸⁄₂₁: the lamina is linear like that
of Cordaites with 16 collateral bundles in the petiole. The presence of a
meristematic band at the base of the lamina affords evidence of a deciduous
habit. The large size of the pith is a striking feature with its central tissues in
the form of transverse diaphragms and a narrower peripheral zone of solid
parenchyma (fig. 483, A, a). The secondary wood of the stele is composed
of tracheids with 2–3 contiguous alternate rows of bordered pits on the
radial walls, but none on the tangential walls. In the stem shown in fig. 483,
A, the secondary wood is preserved only in patches. Numerous blunt teeth
varying in prominence project into the pith; these consist chiefly of serially
disposed centrifugal tracheids distinguished by their spiral and scalariform
structure and by the medullary rays which are broader than those in the
more external xylem. Further reference is made to these perimedullary
strands in the description of the leaf-traces. The medullary rays are
uniseriate and usually 1–6 cells in depth: beyond the secondary wood is a
cambium and a cylinder of secondary phloem (fig. 483, D, ph2) consisting
of tubular elements, presumably sieve-tubes, and elongated secretory sacs.
centripetal elements and, externally, a large amount of centrifugal xylem is
an important feature in which Mesoxylon differs from Cordaites. The
double leaf-traces divide after emerging from the secondary wood and each
strap-like leaf receives several collateral bundles (fig. 483, C). An axillary
bud may occur at the base of each leaf (fig. 483, A, b). The phloem,
including sieve-tubes and secretory sacs, is succeeded by a broad pericycle,
and the comparatively narrow cortex is traversed by successive bands of
periderm. In the outer region of the cortex the presence of radial bands of
fibres is a characteristic feature. The reproductive organs are unknown. The
anatomical features are well illustrated by M. Sutcliffii first described by
Scott, who provisionally placed it in Poroxylon, and afterwards more fully
investigated by Maslen[716].
Mesoxylon Sutcliffii Scott.
The average diameter of the stem is 3 cm.: the section reproduced in fig.
483, A, has a maximum breadth of 3·5 cm.; the leaf-bases cut at different
levels give an irregular contour to the surface like that of a Lepidodendron.
An axillary bud, either reproductive or vegetative, is seen at b consisting of
a short axis bearing crowded bud-scales. The leaves are crowded and
according to Maslen have a phyllotaxis of ⁸⁄₂₁: the lamina is linear like that
of Cordaites with 16 collateral bundles in the petiole. The presence of a
meristematic band at the base of the lamina affords evidence of a deciduous
habit. The large size of the pith is a striking feature with its central tissues in
the form of transverse diaphragms and a narrower peripheral zone of solid
parenchyma (fig. 483, A, a). The secondary wood of the stele is composed
of tracheids with 2–3 contiguous alternate rows of bordered pits on the
radial walls, but none on the tangential walls. In the stem shown in fig. 483,
A, the secondary wood is preserved only in patches. Numerous blunt teeth
varying in prominence project into the pith; these consist chiefly of serially
disposed centrifugal tracheids distinguished by their spiral and scalariform
structure and by the medullary rays which are broader than those in the
more external xylem. Further reference is made to these perimedullary
strands in the description of the leaf-traces. The medullary rays are
uniseriate and usually 1–6 cells in depth: beyond the secondary wood is a
cambium and a cylinder of secondary phloem (fig. 483, D, ph2) consisting
of tubular elements, presumably sieve-tubes, and elongated secretory sacs.
Page 312
The pericycle is composed of several rows of rather large and short cells
and has an ill-defined outer boundary. A succession of arcs of periderm-like
tissue and phellogen, which may invade the pericycle and phloem, forms a
prominent feature in the cortex; radially placed bands of fibres similar to
those in Lyginopteris and other genera occur in the outer cortex. At the edge
of the pith the more prominent projections of xylem are arranged in pairs
(fig. 483, B) and as each pair travels downwards the component strands
gradually fuse[717]. Each bundle of a double trace consists internally of an
arc of centripetal xylem, the elements of which are arranged in rows (fig.
483, B, cp), with a single protoxylem group in the middle of the inner face,
px. It is not clear whether any primary centrifugal tracheids are present, but
there are indications that such are occasionally represented. In most cases
the primary xylem of the leaf-traces is exarch, but the existence of mesarch
bundles is not improbable. The bulk of each foliar bundle is formed of a
fan-shaped mass of secondary centrifugal xylem (fig. 483, B, cf) and an
island of parenchyma occurs next the protoxylem. There is no clearly
defined boundary between the outer or centrifugal xylem of the leaf-traces
and the tracheids of the stem-wood; the latter may consist exclusively of
tracheids with bordered pits or the inner rows of the xylem-cylinder may be
of the scalariform or spiral type. Differences shown in transverse sections of
the inner portion of the xylem are due to the circumstance that in certain
parts of the inner face of the secondary wood leaf-traces are unrepresented,
while in other places the dwindled remains of the outer, centrifugal,
portions of a trace are still recognisable. As each double leaf-trace passes
down the pith the bundles fuse and the single strand retains for a time some
centripetal xylem; this gradually disappears and at a lower level the
centripetal xylem also dies out. The space enclosing the obtuse apices of the
bundles shown in fig. 483, B, was originally occupied by thin-walled tissue
which accompanied the trace in its outward course. In Mesoxylon Sutcliffii
the leaf-strands pass almost horizontally through the secondary wood, bend
outwards in the phloem and follow a steeply ascending course to the leaves.
In fig. 483, B, a double leaf-trace is seen at the inner edge of the secondary
wood with the centrifugal xylem, cf, continuous with that of the stele: fig.
483, D, lt, shows a leaf-trace in the pericycle where one of the bundles has
divided and the other is tangentially extended and partially divided. The
branching is carried further in the cortex, as seen in fig. 483, C, where the
trace is represented by a curved row of six bundles, lt, and at a higher level
and has an ill-defined outer boundary. A succession of arcs of periderm-like
tissue and phellogen, which may invade the pericycle and phloem, forms a
prominent feature in the cortex; radially placed bands of fibres similar to
those in Lyginopteris and other genera occur in the outer cortex. At the edge
of the pith the more prominent projections of xylem are arranged in pairs
(fig. 483, B) and as each pair travels downwards the component strands
gradually fuse[717]. Each bundle of a double trace consists internally of an
arc of centripetal xylem, the elements of which are arranged in rows (fig.
483, B, cp), with a single protoxylem group in the middle of the inner face,
px. It is not clear whether any primary centrifugal tracheids are present, but
there are indications that such are occasionally represented. In most cases
the primary xylem of the leaf-traces is exarch, but the existence of mesarch
bundles is not improbable. The bulk of each foliar bundle is formed of a
fan-shaped mass of secondary centrifugal xylem (fig. 483, B, cf) and an
island of parenchyma occurs next the protoxylem. There is no clearly
defined boundary between the outer or centrifugal xylem of the leaf-traces
and the tracheids of the stem-wood; the latter may consist exclusively of
tracheids with bordered pits or the inner rows of the xylem-cylinder may be
of the scalariform or spiral type. Differences shown in transverse sections of
the inner portion of the xylem are due to the circumstance that in certain
parts of the inner face of the secondary wood leaf-traces are unrepresented,
while in other places the dwindled remains of the outer, centrifugal,
portions of a trace are still recognisable. As each double leaf-trace passes
down the pith the bundles fuse and the single strand retains for a time some
centripetal xylem; this gradually disappears and at a lower level the
centripetal xylem also dies out. The space enclosing the obtuse apices of the
bundles shown in fig. 483, B, was originally occupied by thin-walled tissue
which accompanied the trace in its outward course. In Mesoxylon Sutcliffii
the leaf-strands pass almost horizontally through the secondary wood, bend
outwards in the phloem and follow a steeply ascending course to the leaves.
In fig. 483, B, a double leaf-trace is seen at the inner edge of the secondary
wood with the centrifugal xylem, cf, continuous with that of the stele: fig.
483, D, lt, shows a leaf-trace in the pericycle where one of the bundles has
divided and the other is tangentially extended and partially divided. The
branching is carried further in the cortex, as seen in fig. 483, C, where the
trace is represented by a curved row of six bundles, lt, and at a higher level
Page 313
further subdivision may occur. The leaf-bundles are collateral and in the
leaf retain both centripetal and centrifugal tracheids. In the section shown in
fig. 483, C, the oval stele of an axillary shoot is seen at s subtended by the
row of collateral bundles: the stele has a fairly large pith surrounded by a
zone of secondary xylem with broad medullary rays.
leaf retain both centripetal and centrifugal tracheids. In the section shown in
fig. 483, C, the oval stele of an axillary shoot is seen at s subtended by the
row of collateral bundles: the stele has a fairly large pith surrounded by a
zone of secondary xylem with broad medullary rays.
Page 314
Fig. 483. Mesoxylon Sutcliffii. Transverse sections of stem. A. a, outer
pith; b, axillary bud; x2 secondary xylem. B. cp, cf, centripetal and
centrifugal xylem; px, protoxylem. C. lt, leaf-traces in the cortex; s,
stele of axillary branch; ph2, secondary phloem. D. Leaf-trace
pith; b, axillary bud; x2 secondary xylem. B. cp, cf, centripetal and
centrifugal xylem; px, protoxylem. C. lt, leaf-traces in the cortex; s,
stele of axillary branch; ph2, secondary phloem. D. Leaf-trace
Page 315
bundles, lt, external to the phloem, ph2. (A, C, D, sections in the
Manchester Collection, 717 b; B, Cambridge Botany School, 530.)
Among other species of Mesoxylon mention may be made of M. Lomaxi
and M. poroxyloides. M. Lomaxi Scott and Maslen[718] generally resembles
M. Sutcliffii but shows the following distinctive features: the leaves are
more scattered and less crowded; the twin-bundles of the leaf-traces fuse
immediately on entering the pith, thus appearing for the most part as single
and not double strands in the perimedullary zone; the centripetal xylem is
well developed, the medullary rays are deeper and the outer cortex has
shorter bands of mechanical tissue.
In Mesoxylon poroxyloides Scott and Maslen[719], the twin-bundles of the
traces unite soon after reaching the pith as in M. Lomaxi, the secondary
tracheids have only two rows, or sometimes a single row, of bordered pits
and the tracheids are rather smaller than in M. Lomaxi (20–40μ as compared
with 30–60μ) and the medullary rays are shallower. There is a particularly
broad zone of spiral and reticulate transitional tracheids at the inner edge of
the wood as in Cordaites and in Dadoxylon Pedroi (fig. 476). The leaves of
this species are believed to be represented by the type described by Dr
Benson as Cordaites Felicis (fig. 465)[720], but, as already suggested, it is
very probable that many or possibly nearly all the leaves from British Coal
Measures described as Cordaites may belong to Mesoxylon.
The chief interest of the genus Mesoxylon is its close resemblance in
certain characters to Cordaites and Poroxylon: the presence of strands of
centripetal xylem in the perimedullary region is an important feature in
which Mesoxylon differs from stems assigned (under the generic name
Dadoxylon) to Cordaites. Mesoxylon differs from Poroxylon in having a
discoid pith like that of Cordaites, but a more important difference is the
absence in the leaf-trace xylem of Mesoxylon of bordered pits of the
Araucarian type, whereas in Poroxylon Araucarian pits occur in both the
centripetal and centrifugal tracheids. In Poroxylon the secondary xylem is
manoxylic; in Mesoxylon, as in Cordaites, it is pycnoxylic.
The range of Cordaites and a consideration of other imperfectly known
genera.
Manchester Collection, 717 b; B, Cambridge Botany School, 530.)
Among other species of Mesoxylon mention may be made of M. Lomaxi
and M. poroxyloides. M. Lomaxi Scott and Maslen[718] generally resembles
M. Sutcliffii but shows the following distinctive features: the leaves are
more scattered and less crowded; the twin-bundles of the leaf-traces fuse
immediately on entering the pith, thus appearing for the most part as single
and not double strands in the perimedullary zone; the centripetal xylem is
well developed, the medullary rays are deeper and the outer cortex has
shorter bands of mechanical tissue.
In Mesoxylon poroxyloides Scott and Maslen[719], the twin-bundles of the
traces unite soon after reaching the pith as in M. Lomaxi, the secondary
tracheids have only two rows, or sometimes a single row, of bordered pits
and the tracheids are rather smaller than in M. Lomaxi (20–40μ as compared
with 30–60μ) and the medullary rays are shallower. There is a particularly
broad zone of spiral and reticulate transitional tracheids at the inner edge of
the wood as in Cordaites and in Dadoxylon Pedroi (fig. 476). The leaves of
this species are believed to be represented by the type described by Dr
Benson as Cordaites Felicis (fig. 465)[720], but, as already suggested, it is
very probable that many or possibly nearly all the leaves from British Coal
Measures described as Cordaites may belong to Mesoxylon.
The chief interest of the genus Mesoxylon is its close resemblance in
certain characters to Cordaites and Poroxylon: the presence of strands of
centripetal xylem in the perimedullary region is an important feature in
which Mesoxylon differs from stems assigned (under the generic name
Dadoxylon) to Cordaites. Mesoxylon differs from Poroxylon in having a
discoid pith like that of Cordaites, but a more important difference is the
absence in the leaf-trace xylem of Mesoxylon of bordered pits of the
Araucarian type, whereas in Poroxylon Araucarian pits occur in both the
centripetal and centrifugal tracheids. In Poroxylon the secondary xylem is
manoxylic; in Mesoxylon, as in Cordaites, it is pycnoxylic.
The range of Cordaites and a consideration of other imperfectly known
genera.
Page 316
An increased precision in knowledge derived from anatomical
investigation often tends to demonstrate the untrustworthiness of criteria
based on external features previously employed with confidence. This
inevitable though, from the point of view of the systematist, inconvenient
result of intensive study is well illustrated by the recent discovery of the
stems named by Scott and Maslen Mesoxylon[721]. A separation of Cordaites
from Mesoxylon, which no doubt extended far beyond the British area, is
possible only if well-preserved petrified material is available. The leaves of
Mesoxylon, so far as our imperfect knowledge of them enables us to express
an opinion, are constructed on a plan almost identical with those of
Cordaites and, as already stated, it is almost certain that many of the
impressions referred to Cordaites were borne on Mesoxylon stems. An
additional source of confusion is supplied by the Cordaites-like leaves of
Poroxylon. It is evident, therefore, that even within the limits of the
Carboniferous and Permian formations the recognition of true Cordaites
leaves must often be attended with considerable risk of error. Apart from the
possible confusion between the foliage of Cordaites and Mesoxylon there
are other difficulties as regards detached leaves which depart more or less
widely from the typical Cordaitean form. Leaves such as C. circularis (fig.
468, B) and C. grandifolius emphasise the lack of any thoroughly
satisfactory dividing line separating single pinnules of Cardiopteris or
Cyclopteris on the one hand and leaves of Psygmophyllum on the other
from Cordaites. The petrified buds described as Dolerophyllum[722] have
been quoted by several authors as examples of unexpanded shoots of
Cordaites though anatomical evidence warrants a generic separation. In the
case of species founded on leaves described in this chapter as Cordaites it
should be remembered that further research may necessitate an alteration in
nomenclature.
Among the species included in Cordaites is Noeggerathiopsis Hislopi[723]
(figs. 470–472), a type widely spread in India and in other parts of
Gondwana-Land: if the change of generic name is accepted it involves the
extension of the geographical range of Cordaites from Northern Europe and
North America to the southern botanical province. We have as yet no proof
of the existence of Cordaites in the Arctic regions. The range in time of
Cordaites or of the Cordaitales has generally been stated to be from the
Upper Devonian to the Permian. It is, however, by no means certain that the
genus flourished before the Carboniferous period, though it is clear that
investigation often tends to demonstrate the untrustworthiness of criteria
based on external features previously employed with confidence. This
inevitable though, from the point of view of the systematist, inconvenient
result of intensive study is well illustrated by the recent discovery of the
stems named by Scott and Maslen Mesoxylon[721]. A separation of Cordaites
from Mesoxylon, which no doubt extended far beyond the British area, is
possible only if well-preserved petrified material is available. The leaves of
Mesoxylon, so far as our imperfect knowledge of them enables us to express
an opinion, are constructed on a plan almost identical with those of
Cordaites and, as already stated, it is almost certain that many of the
impressions referred to Cordaites were borne on Mesoxylon stems. An
additional source of confusion is supplied by the Cordaites-like leaves of
Poroxylon. It is evident, therefore, that even within the limits of the
Carboniferous and Permian formations the recognition of true Cordaites
leaves must often be attended with considerable risk of error. Apart from the
possible confusion between the foliage of Cordaites and Mesoxylon there
are other difficulties as regards detached leaves which depart more or less
widely from the typical Cordaitean form. Leaves such as C. circularis (fig.
468, B) and C. grandifolius emphasise the lack of any thoroughly
satisfactory dividing line separating single pinnules of Cardiopteris or
Cyclopteris on the one hand and leaves of Psygmophyllum on the other
from Cordaites. The petrified buds described as Dolerophyllum[722] have
been quoted by several authors as examples of unexpanded shoots of
Cordaites though anatomical evidence warrants a generic separation. In the
case of species founded on leaves described in this chapter as Cordaites it
should be remembered that further research may necessitate an alteration in
nomenclature.
Among the species included in Cordaites is Noeggerathiopsis Hislopi[723]
(figs. 470–472), a type widely spread in India and in other parts of
Gondwana-Land: if the change of generic name is accepted it involves the
extension of the geographical range of Cordaites from Northern Europe and
North America to the southern botanical province. We have as yet no proof
of the existence of Cordaites in the Arctic regions. The range in time of
Cordaites or of the Cordaitales has generally been stated to be from the
Upper Devonian to the Permian. It is, however, by no means certain that the
genus flourished before the Carboniferous period, though it is clear that
Page 317
closely allied types must have lived in pre-Carboniferous floras. The strata
in New Brunswick from which Dawson recorded his supposed Devonian
Cordaites have been shown to be Upper Carboniferous in age[724]. As
regards the length of time during which the Cordaitales existed we have no
decisive evidence. In recent years the tendency has been to extend their
range into the Mesozoic era, and there are several pieces of evidence in
favour of this. There is no doubt that considerations of age based on the
arbitrary divisions of the geological scale sometimes insinuate themselves
too thoroughly into questions connected with the duration of plant-types
whether represented by families or genera. We have been accustomed to
regard Cordaites as a genus confined to the Palaeozoic period, a type which
with many others carried on the tradition of Upper Carboniferous forests to
the Permian floras and then made way for the precursors of Mesozoic types.
There is, however, no valid reason for supposing that Cordaites and other
Palaeozoic genera did not survive as less prominent members in succeeding
floras. It must be admitted that evidence in support of Mesozoic Cordaitales
is not above suspicion, though the probability is that Cordaites or some
allied genera still flourished in the earlier stages of the Mesozoic era. The
data on which this opinion is based cannot be fully discussed in a general
treatise, but a few of the facts may be briefly considered. Zeiller[725] and
other authors have expressed the view that the Cordaitales were not
exclusively Palaeozoic. In addition to Cordaites (Noeggerathiopsis) Hislopi
recorded from Rhaetic floras, other possible representatives of the group are
illustrated by specimens included in such genera as Yuccites, Bambusium
and Krammera.
Pelourdea gen. nov.
The name Yuccites[726] was given to some detached, broad, linear leaves
from the Bunter sandstone of the Vosges which were compared with the
foliage of Yucca and classed among Monocotyledons. The authors of the
genus also described a cylindrical cast as a Yuccites stem, including both
stem and leaves in Yuccites vogesiacus. The supposed stem, as Fliche[727]
has shown, is a pith-cast and is appropriately named by him Endolepis
vogesiacus. The Vosges leaves are assigned by this author to the genus
Cordaites, a change of name which may eventually be justified though as
yet based on insufficient evidence. There are objections to the institution of
in New Brunswick from which Dawson recorded his supposed Devonian
Cordaites have been shown to be Upper Carboniferous in age[724]. As
regards the length of time during which the Cordaitales existed we have no
decisive evidence. In recent years the tendency has been to extend their
range into the Mesozoic era, and there are several pieces of evidence in
favour of this. There is no doubt that considerations of age based on the
arbitrary divisions of the geological scale sometimes insinuate themselves
too thoroughly into questions connected with the duration of plant-types
whether represented by families or genera. We have been accustomed to
regard Cordaites as a genus confined to the Palaeozoic period, a type which
with many others carried on the tradition of Upper Carboniferous forests to
the Permian floras and then made way for the precursors of Mesozoic types.
There is, however, no valid reason for supposing that Cordaites and other
Palaeozoic genera did not survive as less prominent members in succeeding
floras. It must be admitted that evidence in support of Mesozoic Cordaitales
is not above suspicion, though the probability is that Cordaites or some
allied genera still flourished in the earlier stages of the Mesozoic era. The
data on which this opinion is based cannot be fully discussed in a general
treatise, but a few of the facts may be briefly considered. Zeiller[725] and
other authors have expressed the view that the Cordaitales were not
exclusively Palaeozoic. In addition to Cordaites (Noeggerathiopsis) Hislopi
recorded from Rhaetic floras, other possible representatives of the group are
illustrated by specimens included in such genera as Yuccites, Bambusium
and Krammera.
Pelourdea gen. nov.
The name Yuccites[726] was given to some detached, broad, linear leaves
from the Bunter sandstone of the Vosges which were compared with the
foliage of Yucca and classed among Monocotyledons. The authors of the
genus also described a cylindrical cast as a Yuccites stem, including both
stem and leaves in Yuccites vogesiacus. The supposed stem, as Fliche[727]
has shown, is a pith-cast and is appropriately named by him Endolepis
vogesiacus. The Vosges leaves are assigned by this author to the genus
Cordaites, a change of name which may eventually be justified though as
yet based on insufficient evidence. There are objections to the institution of
Page 318
a new name in place of Yuccites, but it is undesirable to retain a designation
suggesting false ideas with regard to affinity. A new name Pelourdea (after
M. Pelourde of Paris, whose recent death deprives Palaeobotany of an able
and promising investigator) is therefore proposed for leaves of the Yuccites
type which in form, venation, and spiral phyllotaxis agree with those of
Cordaites but cannot confidently be assigned to that genus or even to the
Cordaitales. For linear leaves, especially from Jurassic strata, resembling
those of Phoenicopsis the name Desmiophyllum[728] is employed: these are
very similar to those of Pelourdea; they are characterised by their fairly
uniform breadth and afford no indication of their arrangement on the
supporting axis.
Pelourdea vogesiaca (Schimper and Mougeot).
The linear-lanceolate leaves described by Schimper and Mougeot as
Yuccites vogesiacus and transferred by Fliche to Cordaites are probably
specifically identical with specimens described by Mr Wills[729] from Lower
Keuper rocks in Worcestershire. The English leaves were described by
Arber[730] as Zamites grandis,—the name Zamites vogesiacus having been
previously used by Schimper and Mougeot,—on the ground that the
supposed leaves were probably pinnae of a cycadean frond, a view in
agreement with an opinion previously expressed with regard to similar
leaves from Stonesfield[731]. A later discovery by Wills of specimens, on
which the drawing reproduced in fig. 484 is based, of the same type of leaf
showing the foliar nature of the fossils necessitated the abandonment of the
pinna-hypothesis, and the original name Yuccites vogesiacus was
resuscitated[732]. The leaves reach a length of 50 cm. and a maximum
breadth of 6·5 cm.; the lamina is entire, lanceolate or linear-lanceolate, the
apex acuminate, and the lower part rather abruptly contracted and attached
by a broad crescentic base; veins numerous, parallel, and occasionally
forked. Fliche records the occurrence of a small Artisia-like pith-cast and
pieces of stem with leaf-scars (4 × 3 mm.) in association with leaves of
Pelourdea vogesiaca in Triassic strata in Lorraine. An imperfectly
preserved specimen described by Fliche as Cordaianthus Minieri[733]
resembles an inflorescence of Cordaites. It consists of an axis 15 cm. long,
the lower part forming a peduncle, and on the upper portion are linear
bracts subtending oblong bodies which may be lateral fertile shoots.
suggesting false ideas with regard to affinity. A new name Pelourdea (after
M. Pelourde of Paris, whose recent death deprives Palaeobotany of an able
and promising investigator) is therefore proposed for leaves of the Yuccites
type which in form, venation, and spiral phyllotaxis agree with those of
Cordaites but cannot confidently be assigned to that genus or even to the
Cordaitales. For linear leaves, especially from Jurassic strata, resembling
those of Phoenicopsis the name Desmiophyllum[728] is employed: these are
very similar to those of Pelourdea; they are characterised by their fairly
uniform breadth and afford no indication of their arrangement on the
supporting axis.
Pelourdea vogesiaca (Schimper and Mougeot).
The linear-lanceolate leaves described by Schimper and Mougeot as
Yuccites vogesiacus and transferred by Fliche to Cordaites are probably
specifically identical with specimens described by Mr Wills[729] from Lower
Keuper rocks in Worcestershire. The English leaves were described by
Arber[730] as Zamites grandis,—the name Zamites vogesiacus having been
previously used by Schimper and Mougeot,—on the ground that the
supposed leaves were probably pinnae of a cycadean frond, a view in
agreement with an opinion previously expressed with regard to similar
leaves from Stonesfield[731]. A later discovery by Wills of specimens, on
which the drawing reproduced in fig. 484 is based, of the same type of leaf
showing the foliar nature of the fossils necessitated the abandonment of the
pinna-hypothesis, and the original name Yuccites vogesiacus was
resuscitated[732]. The leaves reach a length of 50 cm. and a maximum
breadth of 6·5 cm.; the lamina is entire, lanceolate or linear-lanceolate, the
apex acuminate, and the lower part rather abruptly contracted and attached
by a broad crescentic base; veins numerous, parallel, and occasionally
forked. Fliche records the occurrence of a small Artisia-like pith-cast and
pieces of stem with leaf-scars (4 × 3 mm.) in association with leaves of
Pelourdea vogesiaca in Triassic strata in Lorraine. An imperfectly
preserved specimen described by Fliche as Cordaianthus Minieri[733]
resembles an inflorescence of Cordaites. It consists of an axis 15 cm. long,
the lower part forming a peduncle, and on the upper portion are linear
bracts subtending oblong bodies which may be lateral fertile shoots.
Page 319
Fig. 484. Pelourdea vogesiaca. Reconstruction of a foliage-shoot. (After
Wills.)
Pelourdea hadroclada (Halle).
Dr Halle[734] recently published an account of some imperfect leaves and
stem-fragments from the Rhaetic of Scania which he named Phyllotenia (?)
hadroclada, the generic name provisionally adopted having been proposed
by Salfeld[735] for some rather obscure remains from the Corallian of
Germany. It appears to have escaped the notice of both authors that
Saporta[736] in 1894 had adopted the designation Phyllotenia for some
examples of broad parallel-veined leaves from Lower Cretaceous rocks in
Portugal very similar to Velenovský’s Krammera mirabilis[737]. Some other
generic name must therefore be used. For the Rhaetic species the name
Pelourdea would seem appropriate. The type-specimen consists of an axis
10–12 mm. in diameter with spirally disposed transversely elongated leaf-
Wills.)
Pelourdea hadroclada (Halle).
Dr Halle[734] recently published an account of some imperfect leaves and
stem-fragments from the Rhaetic of Scania which he named Phyllotenia (?)
hadroclada, the generic name provisionally adopted having been proposed
by Salfeld[735] for some rather obscure remains from the Corallian of
Germany. It appears to have escaped the notice of both authors that
Saporta[736] in 1894 had adopted the designation Phyllotenia for some
examples of broad parallel-veined leaves from Lower Cretaceous rocks in
Portugal very similar to Velenovský’s Krammera mirabilis[737]. Some other
generic name must therefore be used. For the Rhaetic species the name
Pelourdea would seem appropriate. The type-specimen consists of an axis
10–12 mm. in diameter with spirally disposed transversely elongated leaf-
Page 320
scars bearing sessile linear leaves similar to Poa-Cordaites; none of them
are complete, the largest is 6 cm. long and 5–7 mm. broad with 8–12
parallel veins. An examination of the original specimens in the Stockholm
Museum satisfied me that Dr Halle is justified in the opinion that they may
be fragments of some Cordaitalean plant and that he was well advised to
avoid the use of the name Cordaites. Salfeld’s species, Phyllotenia
longifolia, may be an imperfectly preserved example of Phoenicopsis[738],
but the material is too incomplete to be identified with any degree of
confidence.
Pelourdea Imhofi (Heer).
The Triassic leaves from Switzerland described by Heer[739], and more
recently by Leuthardt[740], as Bambusium Imhofi, were referred by Fliche[741]
to the genus Cordaites. The lamina is ensiform, 25 cm. long with a
maximum breadth of 2·4 cm. Leuthardt’s photograph of aerial stems and
rhizomes of this supposed Monocotyledon are far from convincing.
Pelourdea keuperiana (Compter).
The leaves from the Lower Keuper of Thuringia assigned by Compter[742]
to Cordaites without adequate evidence resemble those of P. vogesiaca, but
there is no evidence as to their manner of attachment; they are 30–40 cm.
long and from 1·5 to 2 cm. broad.
Pelourdea megaphylla (Phillips).
This species was first described by Phillips[743] from the Middle Jurassic
Stonesfield Slate and afterwards referred to Zamites[744]: the leaves bear a
striking resemblance to foliage of the type Cordaites borassifolius; the
lamina is 30 cm. long and attains a breadth of 3 cm., the apex is acuminate
and slightly contracted towards the broad concave base. My former
comparison of these Stonesfield leaves with the long pinnae of Ceratozamia
mexicana seemed to be supported by Phillips’s type-specimen of
Palaeozamia longifolia. It may be that the supposed pinnae in Phillips’s
type are spirally disposed leaves: if this is the case the specimen may be a
fragment of a Podozamites; its specific identity with the larger detached
specimens, though probable, cannot be demonstrated. Some leaves figured
are complete, the largest is 6 cm. long and 5–7 mm. broad with 8–12
parallel veins. An examination of the original specimens in the Stockholm
Museum satisfied me that Dr Halle is justified in the opinion that they may
be fragments of some Cordaitalean plant and that he was well advised to
avoid the use of the name Cordaites. Salfeld’s species, Phyllotenia
longifolia, may be an imperfectly preserved example of Phoenicopsis[738],
but the material is too incomplete to be identified with any degree of
confidence.
Pelourdea Imhofi (Heer).
The Triassic leaves from Switzerland described by Heer[739], and more
recently by Leuthardt[740], as Bambusium Imhofi, were referred by Fliche[741]
to the genus Cordaites. The lamina is ensiform, 25 cm. long with a
maximum breadth of 2·4 cm. Leuthardt’s photograph of aerial stems and
rhizomes of this supposed Monocotyledon are far from convincing.
Pelourdea keuperiana (Compter).
The leaves from the Lower Keuper of Thuringia assigned by Compter[742]
to Cordaites without adequate evidence resemble those of P. vogesiaca, but
there is no evidence as to their manner of attachment; they are 30–40 cm.
long and from 1·5 to 2 cm. broad.
Pelourdea megaphylla (Phillips).
This species was first described by Phillips[743] from the Middle Jurassic
Stonesfield Slate and afterwards referred to Zamites[744]: the leaves bear a
striking resemblance to foliage of the type Cordaites borassifolius; the
lamina is 30 cm. long and attains a breadth of 3 cm., the apex is acuminate
and slightly contracted towards the broad concave base. My former
comparison of these Stonesfield leaves with the long pinnae of Ceratozamia
mexicana seemed to be supported by Phillips’s type-specimen of
Palaeozamia longifolia. It may be that the supposed pinnae in Phillips’s
type are spirally disposed leaves: if this is the case the specimen may be a
fragment of a Podozamites; its specific identity with the larger detached
specimens, though probable, cannot be demonstrated. Some leaves figured
Page 321
by Zigno[745] from Jurassic rocks of Italy as Yuccites Schimperianus may be
identical with P. megaphylla.
Pelourdea mirabilis (Velenovský ex Corda ms.).
The generic name Krammera, suggested by Corda, was employed by
Velenovský[746] for large Cordaites-like leaves from the Lower Cretaceous
of Bohemia, for casts of cones regarded by him as stems, and for fruit-like
bodies. The leaves, previously described as Flabellaria chamaeropifolia
Goepp., Dammara albens Presl, etc., bear a close resemblance to the large
broadly linear leaves of Cordaites; the lamina reaches a length of 40 cm.
and between the veins occur 1–4 finer striations. The fossils identified by
Velenovský as stems bearing crowded imbricate scales, which he regarded
as the persistent bases of Krammera leaves, are probably cones; they agree
very closely in size and shape, also in the form of the scales, with cones of
Agathis and some other recent Conifers. As the designation Krammera was
instituted primarily for cones and not leaves the name Pelourdea is
substituted for it.
Niponophyllum. Stopes and Fujii.
Niponophyllum cordaitiforme Stopes and Fujii.
The generic name Niponophyllum[747] was proposed for some petrified
specimens of leaves or possibly leaflets from Upper Cretaceous beds in
Japan which, though not definitely assigned to a group or family, are
considered by the authors of the genus ‘to lie [anatomically] somewhere
between Cordaites and Cycadeoidea’ ‘with a closer similarity to the former
than to the latter if we compare the whole Cordaites leaf with our blade.’
The data on which this conclusion is based are, however, insufficient to
justify a reference of Niponophyllum to the Cordaitales or indeed to lend
any substantial support to the opinion that the Japanese specimens are
anatomically more akin to Cordaites than to other plants. The type-species
is represented by two specimens of leaf-fragments about 0·4 mm. thick and
from 6 to 9 mm. broad containing from 21 to 33 vascular bundles; the upper
part of the mesophyll is composed of palisade tissue and the stomata appear
to be confined to the lower epidermis. Each bundle is accompanied by an I-
shaped girder, and small patches of sclerenchyma occur next the upper
identical with P. megaphylla.
Pelourdea mirabilis (Velenovský ex Corda ms.).
The generic name Krammera, suggested by Corda, was employed by
Velenovský[746] for large Cordaites-like leaves from the Lower Cretaceous
of Bohemia, for casts of cones regarded by him as stems, and for fruit-like
bodies. The leaves, previously described as Flabellaria chamaeropifolia
Goepp., Dammara albens Presl, etc., bear a close resemblance to the large
broadly linear leaves of Cordaites; the lamina reaches a length of 40 cm.
and between the veins occur 1–4 finer striations. The fossils identified by
Velenovský as stems bearing crowded imbricate scales, which he regarded
as the persistent bases of Krammera leaves, are probably cones; they agree
very closely in size and shape, also in the form of the scales, with cones of
Agathis and some other recent Conifers. As the designation Krammera was
instituted primarily for cones and not leaves the name Pelourdea is
substituted for it.
Niponophyllum. Stopes and Fujii.
Niponophyllum cordaitiforme Stopes and Fujii.
The generic name Niponophyllum[747] was proposed for some petrified
specimens of leaves or possibly leaflets from Upper Cretaceous beds in
Japan which, though not definitely assigned to a group or family, are
considered by the authors of the genus ‘to lie [anatomically] somewhere
between Cordaites and Cycadeoidea’ ‘with a closer similarity to the former
than to the latter if we compare the whole Cordaites leaf with our blade.’
The data on which this conclusion is based are, however, insufficient to
justify a reference of Niponophyllum to the Cordaitales or indeed to lend
any substantial support to the opinion that the Japanese specimens are
anatomically more akin to Cordaites than to other plants. The type-species
is represented by two specimens of leaf-fragments about 0·4 mm. thick and
from 6 to 9 mm. broad containing from 21 to 33 vascular bundles; the upper
part of the mesophyll is composed of palisade tissue and the stomata appear
to be confined to the lower epidermis. Each bundle is accompanied by an I-
shaped girder, and small patches of sclerenchyma occur next the upper
Page 322
epidermis between the girders; there are no resin-canals: the vascular
bundles are collateral, the xylem is said to be almost entirely centripetal and
exarch, but in the absence of evidence afforded by longitudinal sections the
details of structure cannot be definitely determined. A comparison is made
with Cycadean leaves and with leaves of Araucarineae and Podocarpeae,
also with Cordaites; another type with which Niponophyllum may be
compared is Desmiophyllum Solmsi[748].
The genus is interesting as an example of a petrified gymnospermous
type of leaf characterised by the absence of resin-ducts and transfusion-
tracheids, the possession of collateral, apparently exarch, bundles enclosed
in a double sheath; but the data supplied are insufficient to enable us to
allocate the specimens to a position within the class.
A specimen described by Schenk[749] as Eolirion primigenium from
Lower Cretaceous beds in the Carpathian mountains closely resembles in
habit a foliage-shoot of Poa-Cordaites; the leaves are narrow and linear
with obtuse apices and attached, apparently, in a close spiral. Schenk
assigns the plant to the Monocotyledons, but its systematic position must be
left unsettled.
The list of Mesozoic specimens resembling Cordaites leaves might be
extended. Apart from some Triassic and Rhaetic examples which may well
be Cordaitalean, there are many others which, though similar in form and
venation to Cordaites, are in all probability more closely related to Agathis
and other genera; the species Dammarites Bayeri recently described by
Zeiller[750] from the Upper Cretaceous of Bulgaria is a case in point. The
Araucarian character of the wood of Cordaites precludes any satisfactory
discrimination between Mesozoic Araucarian stems and those of
Cordaitalean species, at least in the case of such material as is usually
available.
Titanophyllum. Renault.
Titanophyllum Grand’Euryi Renault. The remarkable leaves on which
this genus and species are founded[751] were discovered in the Commentry
coalfield; they occur as detached specimens and cannot be correlated with
any known stem. Renault suggests that the Autun stems referred to
bundles are collateral, the xylem is said to be almost entirely centripetal and
exarch, but in the absence of evidence afforded by longitudinal sections the
details of structure cannot be definitely determined. A comparison is made
with Cycadean leaves and with leaves of Araucarineae and Podocarpeae,
also with Cordaites; another type with which Niponophyllum may be
compared is Desmiophyllum Solmsi[748].
The genus is interesting as an example of a petrified gymnospermous
type of leaf characterised by the absence of resin-ducts and transfusion-
tracheids, the possession of collateral, apparently exarch, bundles enclosed
in a double sheath; but the data supplied are insufficient to enable us to
allocate the specimens to a position within the class.
A specimen described by Schenk[749] as Eolirion primigenium from
Lower Cretaceous beds in the Carpathian mountains closely resembles in
habit a foliage-shoot of Poa-Cordaites; the leaves are narrow and linear
with obtuse apices and attached, apparently, in a close spiral. Schenk
assigns the plant to the Monocotyledons, but its systematic position must be
left unsettled.
The list of Mesozoic specimens resembling Cordaites leaves might be
extended. Apart from some Triassic and Rhaetic examples which may well
be Cordaitalean, there are many others which, though similar in form and
venation to Cordaites, are in all probability more closely related to Agathis
and other genera; the species Dammarites Bayeri recently described by
Zeiller[750] from the Upper Cretaceous of Bulgaria is a case in point. The
Araucarian character of the wood of Cordaites precludes any satisfactory
discrimination between Mesozoic Araucarian stems and those of
Cordaitalean species, at least in the case of such material as is usually
available.
Titanophyllum. Renault.
Titanophyllum Grand’Euryi Renault. The remarkable leaves on which
this genus and species are founded[751] were discovered in the Commentry
coalfield; they occur as detached specimens and cannot be correlated with
any known stem. Renault suggests that the Autun stems referred to
Page 323
Colpoxylon may have borne the Titanophyllum leaves, but this correlation
rests only on the dimensions of the stems and the occurrence of transversely
elongated scars on the surface. The lamina is thick and coriaceous, 70–75
cm. long and 20–25 cm. in breadth; the veins are parallel but not branched;
numerous longitudinal striations on the upper surface indicate the presence
of hypodermal stereome-strands; stomata are abundant on the lower surface
and the more or less rectangular cells in the neighbourhood of the stomata
appear to be papillose (fig. 485, A, B). The distal region of the lamina is
often torn into strips (fig. 485, A); the approximately rectangular leaf has a
broad elliptical base 9–10 × 3–4 cm.
Fig. 485. Titanophyllum Grand’Euryi. A, leaves ¹⁄₃₀ nat. size; B, stomata
on the lower surface of the lamina. (After Renault and Zeiller.)
Dr White[752] describes a specimen from the Lower Coal Measures of
Missouri as ? Titanophyllum Brittsii which he speaks of as the thick base of
a leaf similar to that described by Renault but, as White says, no formal
diagnosis is possible without more satisfactory material. Such evidence as is
available suggests that Titanophyllum is a type of Cordaitalean leaf
probably closely allied to Cordaites.
rests only on the dimensions of the stems and the occurrence of transversely
elongated scars on the surface. The lamina is thick and coriaceous, 70–75
cm. long and 20–25 cm. in breadth; the veins are parallel but not branched;
numerous longitudinal striations on the upper surface indicate the presence
of hypodermal stereome-strands; stomata are abundant on the lower surface
and the more or less rectangular cells in the neighbourhood of the stomata
appear to be papillose (fig. 485, A, B). The distal region of the lamina is
often torn into strips (fig. 485, A); the approximately rectangular leaf has a
broad elliptical base 9–10 × 3–4 cm.
Fig. 485. Titanophyllum Grand’Euryi. A, leaves ¹⁄₃₀ nat. size; B, stomata
on the lower surface of the lamina. (After Renault and Zeiller.)
Dr White[752] describes a specimen from the Lower Coal Measures of
Missouri as ? Titanophyllum Brittsii which he speaks of as the thick base of
a leaf similar to that described by Renault but, as White says, no formal
diagnosis is possible without more satisfactory material. Such evidence as is
available suggests that Titanophyllum is a type of Cordaitalean leaf
probably closely allied to Cordaites.
Page 324
Page 325
CHAPTER XXXIV.
CORDAITALES
.
C. PITYEAE.
Pitys. Witham.
This generic name in the form Pitus was first used by Witham[753] for
some petrified pieces of large stems from Lower Carboniferous strata in the
south of Scotland (Berwickshire). In an earlier paper Witham[754] gives an
account of the beds on the banks of the Tweed from which the specimens of
Pitys and other plants were obtained. The name was revived by Goeppert[755]
as a substitute for Pissadendron[756] adopted by Endlicher and Unger:
Scott[757] employed the older name in the account of his investigations,
which have added greatly to our knowledge of Witham’s types. The
distinguishing characters of Pitys are: the Araucarian pitting of the
secondary xylem, the large pith, the occurrence of numerous small primary
xylem strands of mesarch structure in the peripheral region of the pith, and
the simple nature of the leaf-traces. Nothing is known of the extrastelar
tissues, and beyond the fact that the species were arborescent we have no
information with regard to the foliar[758] or reproductive organs.
Pitys antiqua Witham.
In 1899 Scott[759] published a preliminary description of some sections in
the possession of Dr Kidston from Lennel Braes (Berwickshire: Calciferous
series) under the name Araucarioxylon antiquum, but in the more complete
account the name Pitys[760] is adopted. The following description is based on
Scott’s paper and on the examination of the sections. Fig. 486 represents a
diagrammatic sketch of a section (2·7 × 2·7 cm.) of the central region of a
stem which had lost most of its secondary wood. In some cases the pith
reaches a diameter of 3 cm.; it consists of large parenchymatous cells
broader than deep, several of which contain a black substance and are
CORDAITALES
.
C. PITYEAE.
Pitys. Witham.
This generic name in the form Pitus was first used by Witham[753] for
some petrified pieces of large stems from Lower Carboniferous strata in the
south of Scotland (Berwickshire). In an earlier paper Witham[754] gives an
account of the beds on the banks of the Tweed from which the specimens of
Pitys and other plants were obtained. The name was revived by Goeppert[755]
as a substitute for Pissadendron[756] adopted by Endlicher and Unger:
Scott[757] employed the older name in the account of his investigations,
which have added greatly to our knowledge of Witham’s types. The
distinguishing characters of Pitys are: the Araucarian pitting of the
secondary xylem, the large pith, the occurrence of numerous small primary
xylem strands of mesarch structure in the peripheral region of the pith, and
the simple nature of the leaf-traces. Nothing is known of the extrastelar
tissues, and beyond the fact that the species were arborescent we have no
information with regard to the foliar[758] or reproductive organs.
Pitys antiqua Witham.
In 1899 Scott[759] published a preliminary description of some sections in
the possession of Dr Kidston from Lennel Braes (Berwickshire: Calciferous
series) under the name Araucarioxylon antiquum, but in the more complete
account the name Pitys[760] is adopted. The following description is based on
Scott’s paper and on the examination of the sections. Fig. 486 represents a
diagrammatic sketch of a section (2·7 × 2·7 cm.) of the central region of a
stem which had lost most of its secondary wood. In some cases the pith
reaches a diameter of 3 cm.; it consists of large parenchymatous cells
broader than deep, several of which contain a black substance and are
Page 326
probably secretory elements: the intercellular
spaces are fairly large. Horizontally extended
gaps, due to shrinkage and collapse, occur in the
pith and give to it an appearance not unlike that
of Cordaites. Numerous small elliptical strands
of primary xylem, 0·15–0·3 mm. in diameter,
are scattered in the peripheral region (fig. 486)
at varying distances from the inner edge of the
secondary wood and occasionally, when about
to bend outwards as a leaf-trace, a primary Fig. 486. Pitys antiqua.
xylem-strand abuts directly on the secondary Central region of
xylem. The protoxylem occupies a more or less stem, showing
central position in each mesarch strand (fig. primary xylem
487, B, px): the centrifugal tracheids have the strands as black
Araucarian pitting while the centripetal dots. (Kidston
elements are spiral. A few parenchymatous cells Collection, 598 A.)
are associated with the more central tracheids. A leaf-trace about to bend
outwards into the zone of secondary wood is double, but at a slightly higher
level in its course it assumes the form of a single strand. The foliar bundles
are thus single and not true double traces. Scott recognised, at the extreme
edge of the pith, an association with outgoing leaf-traces of a single
reparatory strand deeper in the medullary tissue. In this species there is no
evidence that an outgoing trace is accompanied by an arc of secondary
xylem, but that such was the case is rendered highly probable by the
discovery of an arc of wood added by the cambium to a leaf-trace in Pitys
Withami[761]. The radial disposition of the pith-cells, many of which appear
to be secretory, around each primary xylem-strand (fig. 487, B) is a
characteristic feature. A difficult problem, namely the relation of primary
xylem and phloem, is raised by the fact that the primary strands are
composed exclusively of xylem and are in most cases separated from the
secondary wood by several parenchymatous cells. Scott favours the view
that the primary phloem was originally at some distance from the primary
xylem, the cambium being formed nearer to the phloem, an arrangement
foreign to recent Gymnosperms. It is perhaps conceivable that the primary
conducting strands included no true phloem.
spaces are fairly large. Horizontally extended
gaps, due to shrinkage and collapse, occur in the
pith and give to it an appearance not unlike that
of Cordaites. Numerous small elliptical strands
of primary xylem, 0·15–0·3 mm. in diameter,
are scattered in the peripheral region (fig. 486)
at varying distances from the inner edge of the
secondary wood and occasionally, when about
to bend outwards as a leaf-trace, a primary Fig. 486. Pitys antiqua.
xylem-strand abuts directly on the secondary Central region of
xylem. The protoxylem occupies a more or less stem, showing
central position in each mesarch strand (fig. primary xylem
487, B, px): the centrifugal tracheids have the strands as black
Araucarian pitting while the centripetal dots. (Kidston
elements are spiral. A few parenchymatous cells Collection, 598 A.)
are associated with the more central tracheids. A leaf-trace about to bend
outwards into the zone of secondary wood is double, but at a slightly higher
level in its course it assumes the form of a single strand. The foliar bundles
are thus single and not true double traces. Scott recognised, at the extreme
edge of the pith, an association with outgoing leaf-traces of a single
reparatory strand deeper in the medullary tissue. In this species there is no
evidence that an outgoing trace is accompanied by an arc of secondary
xylem, but that such was the case is rendered highly probable by the
discovery of an arc of wood added by the cambium to a leaf-trace in Pitys
Withami[761]. The radial disposition of the pith-cells, many of which appear
to be secretory, around each primary xylem-strand (fig. 487, B) is a
characteristic feature. A difficult problem, namely the relation of primary
xylem and phloem, is raised by the fact that the primary strands are
composed exclusively of xylem and are in most cases separated from the
secondary wood by several parenchymatous cells. Scott favours the view
that the primary phloem was originally at some distance from the primary
xylem, the cambium being formed nearer to the phloem, an arrangement
foreign to recent Gymnosperms. It is perhaps conceivable that the primary
conducting strands included no true phloem.
Page 327
Fig. 487. Pitys antiqua. A, radial section of secondary xylem; B,
transverse section showing the inner edge of the secondary wood
and two primary-xylem strands with protoxylem, px. (Kidston
Coll.)
The secondary xylem consists of tracheids with 4–5 alternate rows of
hexagonal pits on the radial walls (fig. 487, A) and not infrequently on the
tangential faces. Near the ends of the tracheids the pits are occasionally
more scattered and separate and may be reduced to a single row[762], but on
the whole the pitting is essentially Araucarian. The medullary rays are
generally 4 cells in breadth, but may be 7 cells broad. In depth the rays
extend to 70 cells. As seen in fig. 487, B, the inner ends of the rays are
especially broad owing to the tangential dilatation of the cells. The
innermost secondary tracheids are characterised by pitting intermediate
between spiral and reticulate. There are no regular rings of growth in the
wood.
Pitys primaeva Witham. This species[763], also founded on material from
the Calciferous sandstone of Berwickshire, differs from P. antiqua in the
broader and shorter form and greater breadth of the medullary rays (fig.
488, A, B), also in the larger tracheids and in the less crowded arrangement
of the bordered pits in which the circular form sometimes replaces the
hexagonal type. The structure of the pith is not known, but Scott was able to
recognise in the partially preserved pith of a branch indications of primary-
xylem groups and other features pointing to a close resemblance to P.
antiqua[764]. A piece of stem originally described by Williamson[765] as
Lyginodendron (?) anomalum from the Lower Carboniferous volcanic ash
of the Isle of Arran would appear to be closely related to, if not specifically
transverse section showing the inner edge of the secondary wood
and two primary-xylem strands with protoxylem, px. (Kidston
Coll.)
The secondary xylem consists of tracheids with 4–5 alternate rows of
hexagonal pits on the radial walls (fig. 487, A) and not infrequently on the
tangential faces. Near the ends of the tracheids the pits are occasionally
more scattered and separate and may be reduced to a single row[762], but on
the whole the pitting is essentially Araucarian. The medullary rays are
generally 4 cells in breadth, but may be 7 cells broad. In depth the rays
extend to 70 cells. As seen in fig. 487, B, the inner ends of the rays are
especially broad owing to the tangential dilatation of the cells. The
innermost secondary tracheids are characterised by pitting intermediate
between spiral and reticulate. There are no regular rings of growth in the
wood.
Pitys primaeva Witham. This species[763], also founded on material from
the Calciferous sandstone of Berwickshire, differs from P. antiqua in the
broader and shorter form and greater breadth of the medullary rays (fig.
488, A, B), also in the larger tracheids and in the less crowded arrangement
of the bordered pits in which the circular form sometimes replaces the
hexagonal type. The structure of the pith is not known, but Scott was able to
recognise in the partially preserved pith of a branch indications of primary-
xylem groups and other features pointing to a close resemblance to P.
antiqua[764]. A piece of stem originally described by Williamson[765] as
Lyginodendron (?) anomalum from the Lower Carboniferous volcanic ash
of the Isle of Arran would appear to be closely related to, if not specifically
Page 328
identical with, P. primaeva and, as Scott says, it should at least be included
in the same genus.
Fig. 488. Pitys primaeva. A, transverse section of the secondary xylem;
B, tangential section of the secondary xylem. (From sections of the
type-specimen in the Edinburgh University Botanical
Department.)
Pitys Withami (Lindley and Hutton). The Craigleith Tree.
1831. Pinites Withami Lindley and Hutton, Foss. Flora, Vol. i. Pl. ii.
1831. Pinites medullaris, Ibid. Pl. iii.
1902. Pitys Withami Scott, Trans. R. Soc. Edinb. Vol. xl. p. 354, Pl. ii. fig.
10: Pl. vi. fig. 21.
This species was founded on some sections cut from an incomplete stem
36 feet long obtained in 1826 from the Calciferous sandstone of the
Craigleith quarry near Edinburgh. The specimen named by Lindley and
Hutton Pinites medullaris is no doubt specifically identical with the larger
stem. In the same year (1831) Witham[766] published an account of a still
larger stem from the same locality, 47 ft long and 5 ft in diameter in the
lower part, and in his book the name Pinites Withami is adopted. A large
specimen of this tree is erected in the grounds of the Natural History
Museum, London, and other specimens are preserved in the Edinburgh
Botanic Garden. Goeppert in 1850 referred the species to Dadoxylon and
in the same genus.
Fig. 488. Pitys primaeva. A, transverse section of the secondary xylem;
B, tangential section of the secondary xylem. (From sections of the
type-specimen in the Edinburgh University Botanical
Department.)
Pitys Withami (Lindley and Hutton). The Craigleith Tree.
1831. Pinites Withami Lindley and Hutton, Foss. Flora, Vol. i. Pl. ii.
1831. Pinites medullaris, Ibid. Pl. iii.
1902. Pitys Withami Scott, Trans. R. Soc. Edinb. Vol. xl. p. 354, Pl. ii. fig.
10: Pl. vi. fig. 21.
This species was founded on some sections cut from an incomplete stem
36 feet long obtained in 1826 from the Calciferous sandstone of the
Craigleith quarry near Edinburgh. The specimen named by Lindley and
Hutton Pinites medullaris is no doubt specifically identical with the larger
stem. In the same year (1831) Witham[766] published an account of a still
larger stem from the same locality, 47 ft long and 5 ft in diameter in the
lower part, and in his book the name Pinites Withami is adopted. A large
specimen of this tree is erected in the grounds of the Natural History
Museum, London, and other specimens are preserved in the Edinburgh
Botanic Garden. Goeppert in 1850 referred the species to Dadoxylon and
Page 329
later to Pitys[767], while Brongniart[768] assigned it to his genus Palaeoxylon.
Scott[769], who examined Witham’s sections placed it in Pitys. The pitting of
the secondary tracheids is often multiseriate, but the medullary rays are
narrower than in Pitys antiqua and P. primaeva, rarely exceeding 4 cells in
breadth, though still of the manoxylic type. Primary-xylem strands occur in
the peripheral region of the pith agreeing closely with those of P. antiqua.
There are no regular and continuous annual rings though as Witham stated
there are concentric markings on the wood which superficially resemble
true rings. The leaf-traces are single and in their passage through the
cylinder of wood an arc of secondary tracheids is added to the primary
elements.
Archaeopitys. Scott and Jeffrey.
Archaeopitys Eastmanii Scott and Jeffrey. The genus Archaeopitys[770] has
recently been instituted for a specimen of a stem from the Lower
Carboniferous rocks of Kentucky which differs from Pitys antiqua, the type
with which it is most closely allied, in the position and behaviour of the
primary vascular strands in the pith. The type-specimen is a piece of stem
2·7 cm. in diameter including a solid parenchymatous pith 5·5 mm. broad
and a cylinder of secondary wood. The wood is similar to that of Cordaites;
the tracheids have 2–3 rows of pits but for the most part the details of
structure are not preserved; the medullary rays are both uniseriate and
multiseriate and not very deep; the structure is more Cordaitean than
Cycadean. A characteristic feature is the occurrence of about 30 vascular
bundles in the medullary region: these mesarch strands, with the
protoxylem near the centre, are scattered through the pith and several lie on
the outer edge in contact with the secondary xylem or are partially
embedded in the xylem-cylinder. The examination of a series of sections
demonstrated the fusion of perimedullary with medullary strands and the
occasional union of the strands of both regions with one another. It appears
that the perimedullary strands are the leaf-traces while the strands deeper in
the pith are merely branches from the peripheral leaf-trace strands.
In Pitys antiqua the medullary xylem strands are confined to the outer
zone of the pith and constitute the leaf-traces: in Archaeopitys, on the other
hand, the medullary strands are scattered through the pith and the leaf-
traces are restricted to the circummedullary region in actual contact with the
Scott[769], who examined Witham’s sections placed it in Pitys. The pitting of
the secondary tracheids is often multiseriate, but the medullary rays are
narrower than in Pitys antiqua and P. primaeva, rarely exceeding 4 cells in
breadth, though still of the manoxylic type. Primary-xylem strands occur in
the peripheral region of the pith agreeing closely with those of P. antiqua.
There are no regular and continuous annual rings though as Witham stated
there are concentric markings on the wood which superficially resemble
true rings. The leaf-traces are single and in their passage through the
cylinder of wood an arc of secondary tracheids is added to the primary
elements.
Archaeopitys. Scott and Jeffrey.
Archaeopitys Eastmanii Scott and Jeffrey. The genus Archaeopitys[770] has
recently been instituted for a specimen of a stem from the Lower
Carboniferous rocks of Kentucky which differs from Pitys antiqua, the type
with which it is most closely allied, in the position and behaviour of the
primary vascular strands in the pith. The type-specimen is a piece of stem
2·7 cm. in diameter including a solid parenchymatous pith 5·5 mm. broad
and a cylinder of secondary wood. The wood is similar to that of Cordaites;
the tracheids have 2–3 rows of pits but for the most part the details of
structure are not preserved; the medullary rays are both uniseriate and
multiseriate and not very deep; the structure is more Cordaitean than
Cycadean. A characteristic feature is the occurrence of about 30 vascular
bundles in the medullary region: these mesarch strands, with the
protoxylem near the centre, are scattered through the pith and several lie on
the outer edge in contact with the secondary xylem or are partially
embedded in the xylem-cylinder. The examination of a series of sections
demonstrated the fusion of perimedullary with medullary strands and the
occasional union of the strands of both regions with one another. It appears
that the perimedullary strands are the leaf-traces while the strands deeper in
the pith are merely branches from the peripheral leaf-trace strands.
In Pitys antiqua the medullary xylem strands are confined to the outer
zone of the pith and constitute the leaf-traces: in Archaeopitys, on the other
hand, the medullary strands are scattered through the pith and the leaf-
traces are restricted to the circummedullary region in actual contact with the
Page 330
secondary xylem. In the Devonian genus Callixylon there are similar
strands but they are confined to the edge of the pith and are usually in
contact with the wood as are the circummedullary strands in Archaeopitys.
The grouping of the secondary xylem of Callixylon into wedge-shaped
masses at the inner edge of the cylinder is a characteristic feature; this
feature is less definite in Archaeopitys and absent from Pitys.
Callixylon. Zalessky.
Callixylon Trifilievi Zalessky. This genus is represented by a single
species[771], originally referred to Dadoxylon, founded on material from
Upper Devonian rocks in the Donetz basin, Russia, and based solely on the
anatomical characters of the secondary wood and central region of an
arborescent stem. The wood is pycnoxylic and of the Araucarian type; the
inner portion of the xylem-cylinder is divided into groups, similar to the
regular wedges in a Calamite stem, consisting of tracheids converging
towards an obtuse apex occupied by a primary xylem strand, fig. 489, A, a,
b. On the radial walls of the tracheids the bordered pits not infrequently
form a single row of flattened ovals, but more usually there are two or
sometimes three rows of alternate contiguous pits (fig. 489, B): circular and
separate pits also occur. As Zalessky states, the pits do not always occupy
the whole radial face; unpitted patches sometimes interrupt the continuity of
the pitted areas[772]. Similar circular and more scattered pits are unusually
abundant on the tangential walls. There are no complete rings of growth.
The medullary rays are narrow and, except at their dilated inner ends,
uniseriate; usually one or a few cells deep, they may reach a depth of 12 or
more cells. The pits on the radial walls of the ray-cells are said to be 4–7 in
the field. The pith consists of thin-walled flattened parenchyma frequently
elongated in a radial direction. At the inner edge of the secondary xylem
and generally in contact with it are several anastomosing strands of primary
xylem, mesarch in structure but with the protoxylem nearer the inner edge.
These bundles may be single (fig. 489, A, a) or double (fig. 489, A, b, and
C) and closely resemble those of Pitys antiqua except in their closer
relation to the secondary wood. The leaf-traces have not been described, but
the occurrence of twin-bundles like those in fig. 489, C, suggests that they
were double. The primary-xylem elements show particularly well
strands but they are confined to the edge of the pith and are usually in
contact with the wood as are the circummedullary strands in Archaeopitys.
The grouping of the secondary xylem of Callixylon into wedge-shaped
masses at the inner edge of the cylinder is a characteristic feature; this
feature is less definite in Archaeopitys and absent from Pitys.
Callixylon. Zalessky.
Callixylon Trifilievi Zalessky. This genus is represented by a single
species[771], originally referred to Dadoxylon, founded on material from
Upper Devonian rocks in the Donetz basin, Russia, and based solely on the
anatomical characters of the secondary wood and central region of an
arborescent stem. The wood is pycnoxylic and of the Araucarian type; the
inner portion of the xylem-cylinder is divided into groups, similar to the
regular wedges in a Calamite stem, consisting of tracheids converging
towards an obtuse apex occupied by a primary xylem strand, fig. 489, A, a,
b. On the radial walls of the tracheids the bordered pits not infrequently
form a single row of flattened ovals, but more usually there are two or
sometimes three rows of alternate contiguous pits (fig. 489, B): circular and
separate pits also occur. As Zalessky states, the pits do not always occupy
the whole radial face; unpitted patches sometimes interrupt the continuity of
the pitted areas[772]. Similar circular and more scattered pits are unusually
abundant on the tangential walls. There are no complete rings of growth.
The medullary rays are narrow and, except at their dilated inner ends,
uniseriate; usually one or a few cells deep, they may reach a depth of 12 or
more cells. The pits on the radial walls of the ray-cells are said to be 4–7 in
the field. The pith consists of thin-walled flattened parenchyma frequently
elongated in a radial direction. At the inner edge of the secondary xylem
and generally in contact with it are several anastomosing strands of primary
xylem, mesarch in structure but with the protoxylem nearer the inner edge.
These bundles may be single (fig. 489, A, a) or double (fig. 489, A, b, and
C) and closely resemble those of Pitys antiqua except in their closer
relation to the secondary wood. The leaf-traces have not been described, but
the occurrence of twin-bundles like those in fig. 489, C, suggests that they
were double. The primary-xylem elements show particularly well
Page 331
transitional forms of pitting connecting the multiseriate and scalariform
types.
Callixylon, though conveniently and justly regarded as a distinct genus,
exhibits in its primary xylem a fairly close agreement with Pitys[773]. The
above account is based in part on Zalessky’s description and partly on
specimens in Dr Kidston’s possession.
types.
Callixylon, though conveniently and justly regarded as a distinct genus,
exhibits in its primary xylem a fairly close agreement with Pitys[773]. The
above account is based in part on Zalessky’s description and partly on
specimens in Dr Kidston’s possession.
Page 332
Fig. 489. Callixylon Trifilievi. A, C, the inner margin of the secondary
xylem showing strands of primary xylem, a, b, and C. B, tracheids
of the secondary xylem. (A, C, from photographs supplied by Prof.
Zalessky; B, Cambridge Botany School.)
xylem showing strands of primary xylem, a, b, and C. B, tracheids
of the secondary xylem. (A, C, from photographs supplied by Prof.
Zalessky; B, Cambridge Botany School.)
Page 333
Miss Elkins and W. Wieland[774] have recently described some Upper
Devonian wood from Indiana characterised by a grouping of the circular or
elliptical bordered pits in the radial walls of the tracheids similar to those in
Callixylon Trifilievi which they include together with the Middle Devonian
species Cordaites Newberryi[775] in Zalessky’s genus. Though these two
American species are comparable in the discontinuous arrangement of the
tracheal pits with the Russian type the latter is characterised by the presence
of primary xylem-strands, a feature that has not been recognised in the
American stems: it would seem, then, undesirable to adopt the designation
Callixylon in preference to Dadoxylon unless there is evidence as to similar
characters in the primary region of the xylem.
Coenoxylon. Zalessky.
Coenoxylon Scotti Zalessky. Prof. Zalessky[776] gave the name
Coenoxylon to a small and incomplete piece of stem of doubtful provenance
but possibly from the Ural Permian beds. The pith, 2 cm. broad, consists of
parenchyma associated in the central region with numerous large sclerous
cells. In one section a sinuous band of meristematic tissue was observed
near the periphery of the pith: the appearance of this tissue in a photograph
given to me by Prof. Zalessky suggests comparison with occasional strips
of similar dividing cells in the pith of Lyginopteris. The secondary wood is
composed of tracheids with 1–2 rows of flattened or hexagonal pits on the
radial walls and narrow uniseriate medullary rays reaching a depth of 15
cells and with 2–7 oval pits in the field. As in the wood of Mesopitys
Tchihatcheffi[777] there are distinct and apparently complete rings of growth.
It is on the ground of the arrangement and structure of the primary xylem
that Zalessky instituted a new generic name. The primary xylem forms teeth
of variable size which project into the pith from the edge of the secondary
xylem: the prominent portions of the main mass of primary xylem give off
branches, differing considerably in size and shape, some of which become
separated by a comparatively broad band of parenchyma from the parent
xylem-tissue. These bundles anastomose in their course through the pith
and in doing so incorporate between them patches of parenchyma. The
bundles of primary xylem are endarch. From the centrifugal strands at the
periphery of the pith double leaf-traces are produced which pass almost
horizontally through the secondary wood. As Zalessky points out, the leaf-
Devonian wood from Indiana characterised by a grouping of the circular or
elliptical bordered pits in the radial walls of the tracheids similar to those in
Callixylon Trifilievi which they include together with the Middle Devonian
species Cordaites Newberryi[775] in Zalessky’s genus. Though these two
American species are comparable in the discontinuous arrangement of the
tracheal pits with the Russian type the latter is characterised by the presence
of primary xylem-strands, a feature that has not been recognised in the
American stems: it would seem, then, undesirable to adopt the designation
Callixylon in preference to Dadoxylon unless there is evidence as to similar
characters in the primary region of the xylem.
Coenoxylon. Zalessky.
Coenoxylon Scotti Zalessky. Prof. Zalessky[776] gave the name
Coenoxylon to a small and incomplete piece of stem of doubtful provenance
but possibly from the Ural Permian beds. The pith, 2 cm. broad, consists of
parenchyma associated in the central region with numerous large sclerous
cells. In one section a sinuous band of meristematic tissue was observed
near the periphery of the pith: the appearance of this tissue in a photograph
given to me by Prof. Zalessky suggests comparison with occasional strips
of similar dividing cells in the pith of Lyginopteris. The secondary wood is
composed of tracheids with 1–2 rows of flattened or hexagonal pits on the
radial walls and narrow uniseriate medullary rays reaching a depth of 15
cells and with 2–7 oval pits in the field. As in the wood of Mesopitys
Tchihatcheffi[777] there are distinct and apparently complete rings of growth.
It is on the ground of the arrangement and structure of the primary xylem
that Zalessky instituted a new generic name. The primary xylem forms teeth
of variable size which project into the pith from the edge of the secondary
xylem: the prominent portions of the main mass of primary xylem give off
branches, differing considerably in size and shape, some of which become
separated by a comparatively broad band of parenchyma from the parent
xylem-tissue. These bundles anastomose in their course through the pith
and in doing so incorporate between them patches of parenchyma. The
bundles of primary xylem are endarch. From the centrifugal strands at the
periphery of the pith double leaf-traces are produced which pass almost
horizontally through the secondary wood. As Zalessky points out, the leaf-
Page 334
traces in their dual nature and in the elongated and narrow form of the
tracheal groups, as seen in tangential section of the secondary wood, bear a
close resemblance to those of Ginkgo biloba.
This Russian genus agrees in its double leaf-trace with Mesoxylon,
Mesopitys, and Antarcticoxylon: among recent plants Ginkgo would seem to
be the most closely allied type.
Parapitys. Zalessky.
The designation Parapitys[778] has been proposed for a single Upper
Carboniferous species characterised by the possession of secondary wood
like that of Cordaites, double leaf-traces, and small mesarch primary
xylem-strands. Nothing is known of the leaves or reproductive organs.
Parapitys Spenceri (Scott).
In 1880 Williamson[779] published a short account of a transverse section
of a specimen found by Mr J. Spencer in Upper Carboniferous strata near
Halifax in Yorkshire which afforded evidence of the occurrence of double
leaf-traces. The following description is taken from Scott’s account[780] of
the species, which he named Dadoxylon Spenceri. The parenchymatous
pith, 5–6 mm. in diameter, is obtusely pentagonal, the prominent angles
corresponding to the points of exit of paired leaf-traces like those of
Mesoxylon, Ginkgo, and other genera. The secondary xylem consists of
narrow tracheids with crowded multiseriate pits on the radial walls and
narrow medullary rays one-cell broad and 1–8 cells deep. In contact with
the inner margin of the secondary wood are a few small mesarch strands of
primary xylem, the protoxylem and some parenchyma occupying a more or
less central position. A leaf-trace about to enter the secondary xylem is
represented by twin-bundles which retain their double nature as they
traverse the stele, but at a lower level the two components fuse and appear
as single bundles at the outer edge of the pith. The division of a leaf-trace
into two before passing out, as in Poroxylon, constitutes a difference from
Lyginopteris in which the division occurs later.
Zalessky’s generic name Parapitys is an appropriate substitute for
Dadoxylon in view of the presence of separate primary xylem strands, a
feature foreign to typical Dadoxylons which agree with recent Conifers and
tracheal groups, as seen in tangential section of the secondary wood, bear a
close resemblance to those of Ginkgo biloba.
This Russian genus agrees in its double leaf-trace with Mesoxylon,
Mesopitys, and Antarcticoxylon: among recent plants Ginkgo would seem to
be the most closely allied type.
Parapitys. Zalessky.
The designation Parapitys[778] has been proposed for a single Upper
Carboniferous species characterised by the possession of secondary wood
like that of Cordaites, double leaf-traces, and small mesarch primary
xylem-strands. Nothing is known of the leaves or reproductive organs.
Parapitys Spenceri (Scott).
In 1880 Williamson[779] published a short account of a transverse section
of a specimen found by Mr J. Spencer in Upper Carboniferous strata near
Halifax in Yorkshire which afforded evidence of the occurrence of double
leaf-traces. The following description is taken from Scott’s account[780] of
the species, which he named Dadoxylon Spenceri. The parenchymatous
pith, 5–6 mm. in diameter, is obtusely pentagonal, the prominent angles
corresponding to the points of exit of paired leaf-traces like those of
Mesoxylon, Ginkgo, and other genera. The secondary xylem consists of
narrow tracheids with crowded multiseriate pits on the radial walls and
narrow medullary rays one-cell broad and 1–8 cells deep. In contact with
the inner margin of the secondary wood are a few small mesarch strands of
primary xylem, the protoxylem and some parenchyma occupying a more or
less central position. A leaf-trace about to enter the secondary xylem is
represented by twin-bundles which retain their double nature as they
traverse the stele, but at a lower level the two components fuse and appear
as single bundles at the outer edge of the pith. The division of a leaf-trace
into two before passing out, as in Poroxylon, constitutes a difference from
Lyginopteris in which the division occurs later.
Zalessky’s generic name Parapitys is an appropriate substitute for
Dadoxylon in view of the presence of separate primary xylem strands, a
feature foreign to typical Dadoxylons which agree with recent Conifers and
Page 335
Cycads in the absence of vascular strands distinct from the endarch
centrifugal wood. As Scott[781] says, Parapitys ‘is best regarded as a near
ally of Mesoxylon.’
Mesopitys. Zalessky.
Mesopitys Tchihatcheffi (Goeppert). The genus Mesopitys was instituted
by Zalessky for a Permian species founded by Goeppert[782] on a piece of
decorticated stem from the Kousnetzk basin in Siberia and afterwards more
fully described by Goeppert and Stenzel[783]. The structure of the secondary
wood led Goeppert to adopt the name Araucarites for which Kraus[784]
substituted Araucarioxylon. A recent investigation of additional material by
Zalessky brought to light the existence of groups of primary xylem abutting
on the secondary xylem and projecting into the pith, characterised by the
occurrence of spiral protoxylem elements on the inner edge. The
recognition of this important feature justified Zalessky in the adoption of a
new generic term. In general anatomical characters Mesopitys agrees with
Eristophyton Beinertianum (Goepp.) but is distinguished by the more feebly
developed primary-xylem groups and by their endarch structure.
The examination of sections from some of Prof. Zalessky’s material lent
to me by Dr Kidston enables me to confirm Zalessky’s description, though I
am not convinced that the primary xylem-strands are exclusively endarch:
in most of the primary groups the protoxylem is clearly on the inner edge,
but in a few cases there may be a small amount of centripetal xylem
present. The characters of Mesopitys Tchihatcheffi may be summarised as
follows:
Annual rings well defined, varying considerably in breadth; the summer
wood is represented by several rows of narrower tracheids (fig. 490, A). In
the piece of stem shown in the figure the breadth of the wood from the
flattened and crushed pith to the broken outer edge is 6 cm. The medullary
rays are numerous, uniseriate, rarely 2 cells in breadth; the pits on the radial
walls of the ray-cells, 7–10 in the field, are apparently simple, oval, and
oblique: the rays are generally 3–4 cells in depth but may be deeper. There
are 1–3 rows of hexagonal alternate rows of pits on the radial walls of the
tracheids. The primary xylem consists of groups, varying in size and
sometimes reduced to a very few elements, in contact with the secondary
centrifugal wood. As Scott[781] says, Parapitys ‘is best regarded as a near
ally of Mesoxylon.’
Mesopitys. Zalessky.
Mesopitys Tchihatcheffi (Goeppert). The genus Mesopitys was instituted
by Zalessky for a Permian species founded by Goeppert[782] on a piece of
decorticated stem from the Kousnetzk basin in Siberia and afterwards more
fully described by Goeppert and Stenzel[783]. The structure of the secondary
wood led Goeppert to adopt the name Araucarites for which Kraus[784]
substituted Araucarioxylon. A recent investigation of additional material by
Zalessky brought to light the existence of groups of primary xylem abutting
on the secondary xylem and projecting into the pith, characterised by the
occurrence of spiral protoxylem elements on the inner edge. The
recognition of this important feature justified Zalessky in the adoption of a
new generic term. In general anatomical characters Mesopitys agrees with
Eristophyton Beinertianum (Goepp.) but is distinguished by the more feebly
developed primary-xylem groups and by their endarch structure.
The examination of sections from some of Prof. Zalessky’s material lent
to me by Dr Kidston enables me to confirm Zalessky’s description, though I
am not convinced that the primary xylem-strands are exclusively endarch:
in most of the primary groups the protoxylem is clearly on the inner edge,
but in a few cases there may be a small amount of centripetal xylem
present. The characters of Mesopitys Tchihatcheffi may be summarised as
follows:
Annual rings well defined, varying considerably in breadth; the summer
wood is represented by several rows of narrower tracheids (fig. 490, A). In
the piece of stem shown in the figure the breadth of the wood from the
flattened and crushed pith to the broken outer edge is 6 cm. The medullary
rays are numerous, uniseriate, rarely 2 cells in breadth; the pits on the radial
walls of the ray-cells, 7–10 in the field, are apparently simple, oval, and
oblique: the rays are generally 3–4 cells in depth but may be deeper. There
are 1–3 rows of hexagonal alternate rows of pits on the radial walls of the
tracheids. The primary xylem consists of groups, varying in size and
sometimes reduced to a very few elements, in contact with the secondary
Page 336
xylem, usually though probably not invariably endarch. In the two narrow
radially elongated and partially destroyed primary strands shown in fig.
490, B, the protoxylem, px, is on the inner edge. The leaf-trace passes
through the secondary wood as a single strand. In the section reproduced in
fig. 490, A, the crushed and flattened pith measures 9 by 2 mm.; it consists
of thin-walled parenchyma with a few scattered thicker-walled cells.
Nothing is known as to the structure of the cortical tissue or leaves.
Fig. 490. Mesopitys Tchihatcheffi. A, transverse section showing rings of
growth in the wood. B, primary xylem with protoxylem, px, and
the edge of the secondary xylem, x2. (Kidston collection, 2156.)
Antarcticoxylon. Seward.
Antarcticoxylon Priestleyi Seward. The specimen on which this genus
was founded was discovered by Mr Raymond Priestley[785] in a boulder,
probably derived from the Upper Beacon sandstone, on the Priestley
Glacier south of 74° S. lat. in the course of the journey of the Northern
Party of Capt. Scott’s second Antarctic Expedition. The type-specimen is a
piece of silicified stem 1 ft long and 3 ins. in diameter; there were no tissues
preserved external to the secondary wood and it is impossible to say what
proportion of the original thickness is represented. Annual rings are clearly
marked at least macroscopically (fig. 491, C) though there is very little
difference between the spring and summer tracheids: the centre of the
compressed stem is occupied by a lighter coloured elliptical area 7 × 2 mm.
which superficially resembles a pith, but in the peripheral region it consists
radially elongated and partially destroyed primary strands shown in fig.
490, B, the protoxylem, px, is on the inner edge. The leaf-trace passes
through the secondary wood as a single strand. In the section reproduced in
fig. 490, A, the crushed and flattened pith measures 9 by 2 mm.; it consists
of thin-walled parenchyma with a few scattered thicker-walled cells.
Nothing is known as to the structure of the cortical tissue or leaves.
Fig. 490. Mesopitys Tchihatcheffi. A, transverse section showing rings of
growth in the wood. B, primary xylem with protoxylem, px, and
the edge of the secondary xylem, x2. (Kidston collection, 2156.)
Antarcticoxylon. Seward.
Antarcticoxylon Priestleyi Seward. The specimen on which this genus
was founded was discovered by Mr Raymond Priestley[785] in a boulder,
probably derived from the Upper Beacon sandstone, on the Priestley
Glacier south of 74° S. lat. in the course of the journey of the Northern
Party of Capt. Scott’s second Antarctic Expedition. The type-specimen is a
piece of silicified stem 1 ft long and 3 ins. in diameter; there were no tissues
preserved external to the secondary wood and it is impossible to say what
proportion of the original thickness is represented. Annual rings are clearly
marked at least macroscopically (fig. 491, C) though there is very little
difference between the spring and summer tracheids: the centre of the
compressed stem is occupied by a lighter coloured elliptical area 7 × 2 mm.
which superficially resembles a pith, but in the peripheral region it consists
Page 337
of portions of a cylinder of spiral and scalariform tracheids, the actual pith
being not more than 2–3 mm. in breadth. The pith consists of lacunar
parenchyma separated by horizontal bands of dark cells containing some
secreted substance (fig. 491, F): the preservation is, however, not
sufficiently good to enable one to describe it in detail. The secondary xylem
is of the pycnoxylic type; the tracheids have either a single row of
contiguous and partially flattened pits on their radial walls or a double row
of alternate polygonal pits; the medullary rays are nearly always uniseriate
(fig. 491, E) and from 1 to 24 cells in depth. At the inner edge of the
secondary wood there was a fairly broad zone of more delicate tracheids
(fig. 491, A, x) characterised by spiral or scalariform bands and by their
relatively small diameter. This innermost zone, which supplies the leaf-
traces, is spoken of as the primary xylem; it appears to be endarch though
this cannot be definitely determined. A characteristic feature of the primary
xylem in the perimedullary region, as also in the leaf-traces on their way
through the secondary wood, is the presence of short and broad tracheids
(fig. 491, D, t) with reticulate thickening bands: these short elements may
represent centripetal xylem and are similar to the short tracheids described
by Scott[786] in the sheath of Mesoxylon Lomaxi and to the larger elements in
the stem of Megaloxylon[787].
An interesting feature seen in transverse sections of the secondary wood
is the occurrence of light bands concentric with the rings of growth which
are broadest near the long axis of the stem (fig. 491, C). In their narrower
parts these bands are clearly due to the partial destruction of the secondary
tracheids, but in other places crushed parenchymatous tissue occurs which
may be a traumatic phenomenon or possibly comparable with Nördlinger’s
‘medullary spots[788]’ formed by local hypertrophy of medullary tissue.
Although the structure of the leaf-traces cannot be definitely determined, it
would seem that each trace passed into the perimedullary region as a single
bundle of relatively large size composed of spiral and scalariform tracheids
narrower than the secondary elements. The traces during their outward
course were accompanied by some parenchymatous tissue continuous with
that in the pith, and the inner spiral tracheids of the trace were connected
with isodiametric reticulate elements. The dimensions of the leaf-traces
point to leaves of fairly large size.
being not more than 2–3 mm. in breadth. The pith consists of lacunar
parenchyma separated by horizontal bands of dark cells containing some
secreted substance (fig. 491, F): the preservation is, however, not
sufficiently good to enable one to describe it in detail. The secondary xylem
is of the pycnoxylic type; the tracheids have either a single row of
contiguous and partially flattened pits on their radial walls or a double row
of alternate polygonal pits; the medullary rays are nearly always uniseriate
(fig. 491, E) and from 1 to 24 cells in depth. At the inner edge of the
secondary wood there was a fairly broad zone of more delicate tracheids
(fig. 491, A, x) characterised by spiral or scalariform bands and by their
relatively small diameter. This innermost zone, which supplies the leaf-
traces, is spoken of as the primary xylem; it appears to be endarch though
this cannot be definitely determined. A characteristic feature of the primary
xylem in the perimedullary region, as also in the leaf-traces on their way
through the secondary wood, is the presence of short and broad tracheids
(fig. 491, D, t) with reticulate thickening bands: these short elements may
represent centripetal xylem and are similar to the short tracheids described
by Scott[786] in the sheath of Mesoxylon Lomaxi and to the larger elements in
the stem of Megaloxylon[787].
An interesting feature seen in transverse sections of the secondary wood
is the occurrence of light bands concentric with the rings of growth which
are broadest near the long axis of the stem (fig. 491, C). In their narrower
parts these bands are clearly due to the partial destruction of the secondary
tracheids, but in other places crushed parenchymatous tissue occurs which
may be a traumatic phenomenon or possibly comparable with Nördlinger’s
‘medullary spots[788]’ formed by local hypertrophy of medullary tissue.
Although the structure of the leaf-traces cannot be definitely determined, it
would seem that each trace passed into the perimedullary region as a single
bundle of relatively large size composed of spiral and scalariform tracheids
narrower than the secondary elements. The traces during their outward
course were accompanied by some parenchymatous tissue continuous with
that in the pith, and the inner spiral tracheids of the trace were connected
with isodiametric reticulate elements. The dimensions of the leaf-traces
point to leaves of fairly large size.
Page 338
Fig. 491. A–F, Antarcticoxylon Priestleyi. A, B, transverse sections of the
xylem; a, small tracheids simulating protoxylem; x, xylem at the
edge of the pith. C, transverse section showing leaf-traces, l, a, b.
D, leaf-trace with short tracheids, t, in the pith; s, sclerous cells. E,
tangential section. F, pith in longitudinal section. G, Pityosporites
antarcticus; see Vol. iv. (All the sections are in the British
Museum.)
xylem; a, small tracheids simulating protoxylem; x, xylem at the
edge of the pith. C, transverse section showing leaf-traces, l, a, b.
D, leaf-trace with short tracheids, t, in the pith; s, sclerous cells. E,
tangential section. F, pith in longitudinal section. G, Pityosporites
antarcticus; see Vol. iv. (All the sections are in the British
Museum.)
Page 339
In the structure of the secondary wood Antarcticoxylon agrees on the
whole with an Araucarian stem: the broad zone of xylem composed of
spiral and scalariform tracheids at the edge of the pith is a feature common
to Mesoxylon, Cordaites, and Araucaria. There is no evidence of the
occurrence of double leaf-traces such as characterise certain Cordaitalean
genera and some existing members of the Araucarineae. In the single nature
of the leaf-traces the Antarctic stem resembles Mesopitys Tchihatcheffi also
in the presence of rings of growth[789], but in Antarcticoxylon the
preservation of the primary xylem is too imperfect to admit of any
satisfactory comparison as regards this important tissue with other types.
The precise age of the Beacon sandstone has not been determined, but the
probability is that the upper beds from which the boulder containing
Antarcticoxylon was derived are not older than the Rhaetic period. The
chief interest of this imperfectly preserved stem with undoubted Araucarian
affinities is its occurrence in the rocks of Antarctica in association with
other remains of comparatively large stems.
whole with an Araucarian stem: the broad zone of xylem composed of
spiral and scalariform tracheids at the edge of the pith is a feature common
to Mesoxylon, Cordaites, and Araucaria. There is no evidence of the
occurrence of double leaf-traces such as characterise certain Cordaitalean
genera and some existing members of the Araucarineae. In the single nature
of the leaf-traces the Antarctic stem resembles Mesopitys Tchihatcheffi also
in the presence of rings of growth[789], but in Antarcticoxylon the
preservation of the primary xylem is too imperfect to admit of any
satisfactory comparison as regards this important tissue with other types.
The precise age of the Beacon sandstone has not been determined, but the
probability is that the upper beds from which the boulder containing
Antarcticoxylon was derived are not older than the Rhaetic period. The
chief interest of this imperfectly preserved stem with undoubted Araucarian
affinities is its occurrence in the rocks of Antarctica in association with
other remains of comparatively large stems.
Page 340
Page 341
CHAPTER XXXV.
PALAEOZOIC GYMNOSPERMOUS SEEDS.
Seeds are abundantly represented as fossils from Carboniferous to Post-
Tertiary deposits. The importance of fossil and sub-fossil species in the later
geological series has been demonstrated by the investigations of Mr and
Mrs Clement Reid and a few other workers in this neglected field. In cases
where it is possible to assign seeds to their parent-plants the descriptions of
casts, impressions, or petrifactions are added to the account of vegetative
organs; but it frequently happens that seeds are preserved only as detached
specimens many of which have little or no value as botanical records, while
others that afford striking examples of the possibilities of petrifaction as a
means of preserving the most delicate structures, are of great importance. In
Volume ii. an account was given of such Palaeozoic seed-bearing organs as
Lepidocarpon and Miadesmia, and the genera Lagenostoma, Sphaerostoma,
and Trigonocarpus are dealt with in this volume under Lyginopteris,
Heterangium, and Medullosa. Certain seeds afford some evidence as to the
systematic position of the parent-plants though insufficient to warrant more
than a surmise as to the nature of the vegetative organs: in several cases it is
only from the resemblance of detached seeds to types that on the strength of
more or less convincing evidence are referred to definite parent-plants that
any conclusions can be drawn with regard to precise systematic position. In
view of the occurrence of several different types of seeds that retain their
morphological features, but cannot be assigned with any degree of certainty
to genera founded on vegetative organs, a special chapter is devoted to a
comparative study of selected examples with the object of directing
attention to data bearing on evolutionary problems. The chief interest of
Palaeozoic seeds to the botanist lies in the facts they contribute towards the
elucidation of questions connected with the promotion of the
megasporangium and megaspore of the Pteridophyta to the higher stage
represented by the integumented megasporangium (nucellus) and single
megaspore that in the main fulfil the definition of a seed[790]. ‘With the
evolution of the seed,’ as Oliver says, ‘the plant rose at a bound to a higher
plane, and this structure in its perfected form has become the very centre of
PALAEOZOIC GYMNOSPERMOUS SEEDS.
Seeds are abundantly represented as fossils from Carboniferous to Post-
Tertiary deposits. The importance of fossil and sub-fossil species in the later
geological series has been demonstrated by the investigations of Mr and
Mrs Clement Reid and a few other workers in this neglected field. In cases
where it is possible to assign seeds to their parent-plants the descriptions of
casts, impressions, or petrifactions are added to the account of vegetative
organs; but it frequently happens that seeds are preserved only as detached
specimens many of which have little or no value as botanical records, while
others that afford striking examples of the possibilities of petrifaction as a
means of preserving the most delicate structures, are of great importance. In
Volume ii. an account was given of such Palaeozoic seed-bearing organs as
Lepidocarpon and Miadesmia, and the genera Lagenostoma, Sphaerostoma,
and Trigonocarpus are dealt with in this volume under Lyginopteris,
Heterangium, and Medullosa. Certain seeds afford some evidence as to the
systematic position of the parent-plants though insufficient to warrant more
than a surmise as to the nature of the vegetative organs: in several cases it is
only from the resemblance of detached seeds to types that on the strength of
more or less convincing evidence are referred to definite parent-plants that
any conclusions can be drawn with regard to precise systematic position. In
view of the occurrence of several different types of seeds that retain their
morphological features, but cannot be assigned with any degree of certainty
to genera founded on vegetative organs, a special chapter is devoted to a
comparative study of selected examples with the object of directing
attention to data bearing on evolutionary problems. The chief interest of
Palaeozoic seeds to the botanist lies in the facts they contribute towards the
elucidation of questions connected with the promotion of the
megasporangium and megaspore of the Pteridophyta to the higher stage
represented by the integumented megasporangium (nucellus) and single
megaspore that in the main fulfil the definition of a seed[790]. ‘With the
evolution of the seed,’ as Oliver says, ‘the plant rose at a bound to a higher
plane, and this structure in its perfected form has become the very centre of
Page 342
the plant’s existence[791].’ We can as yet form a very partial conception of the
successive stages in the adoption of the seed-habit, but since 1855, the year
in which Hooker and Binney[792] published their paper on the structure of
Trigonocarpus, ample proof has been furnished of the importance of
Palaeozoic seeds from the standpoint of affinity between recent
Gymnosperms and extinct seed-bearing plants, and of the modus operandi
of evolutionary tendencies. A cursory examination of Palaeozoic seeds
suffices to demonstrate their resemblance to those of recent Cycads and the
seed of Ginkgo biloba; but while it is clearly with these Gymnosperms that
the majority of the seeds described in the following pages are most closely
allied, the extinct types possess many distinguishing features that throw
light on some at least of the factors concerned in the production of the
modern type. In many of the Palaeozoic seeds the nucellus stands free
within the integument, to which it is attached only in the chalazal region, in
contrast to the lateral union between integument and nucellus in the ovules
of recent Cycads. It has been suggested by Oliver[793] that the seed of the
Conifer Torreya affords a clue to the interpretation of this difference and
that the lower part of the seed in Cycads and Torreya represents a later
intercalation in the basal portion of the ovule, the ancient type having a free
nucellus in contrast to the nucellus of modern seeds which is free only at
the apex. It has been objected[794] that there are no adequate grounds for
assuming the addition of an intercalated zone or of the elongation of the
ovule that this implies, the more probable view being that the lateral union
of nucellus and integument represents congenital fusion in the ancestral
type, a fusion comparable with that of the coherent petals of a gamopetalous
corolla. In the presence of a pollen-chamber most of the Palaeozoic seeds
agree with those of recent Cycads, but in the extinct forms it is usually a
more highly developed structure. The name pollen-chamber was given by
Brongniart[795] to the pollen-containing cavity in the free region of the
nucellus in the petrified seeds from St Étienne in ignorance of the use of the
same term by Griffith[796] in a posthumous work published in 1852 for the
nucellar chamber in Cycas[797]. The genus Stephanospermum (fig. 494, A)
illustrates the means by which the pollen-chamber was liberally supplied
with water and thus adapted to the requirements of fertilisation by motile
gametes. The pollen-chamber and its vascular supply paved the way for
siphonogamy, that is the development of a pollen-tube for the more direct
transmission of the male sperms. The highly developed mantle of tracheal
successive stages in the adoption of the seed-habit, but since 1855, the year
in which Hooker and Binney[792] published their paper on the structure of
Trigonocarpus, ample proof has been furnished of the importance of
Palaeozoic seeds from the standpoint of affinity between recent
Gymnosperms and extinct seed-bearing plants, and of the modus operandi
of evolutionary tendencies. A cursory examination of Palaeozoic seeds
suffices to demonstrate their resemblance to those of recent Cycads and the
seed of Ginkgo biloba; but while it is clearly with these Gymnosperms that
the majority of the seeds described in the following pages are most closely
allied, the extinct types possess many distinguishing features that throw
light on some at least of the factors concerned in the production of the
modern type. In many of the Palaeozoic seeds the nucellus stands free
within the integument, to which it is attached only in the chalazal region, in
contrast to the lateral union between integument and nucellus in the ovules
of recent Cycads. It has been suggested by Oliver[793] that the seed of the
Conifer Torreya affords a clue to the interpretation of this difference and
that the lower part of the seed in Cycads and Torreya represents a later
intercalation in the basal portion of the ovule, the ancient type having a free
nucellus in contrast to the nucellus of modern seeds which is free only at
the apex. It has been objected[794] that there are no adequate grounds for
assuming the addition of an intercalated zone or of the elongation of the
ovule that this implies, the more probable view being that the lateral union
of nucellus and integument represents congenital fusion in the ancestral
type, a fusion comparable with that of the coherent petals of a gamopetalous
corolla. In the presence of a pollen-chamber most of the Palaeozoic seeds
agree with those of recent Cycads, but in the extinct forms it is usually a
more highly developed structure. The name pollen-chamber was given by
Brongniart[795] to the pollen-containing cavity in the free region of the
nucellus in the petrified seeds from St Étienne in ignorance of the use of the
same term by Griffith[796] in a posthumous work published in 1852 for the
nucellar chamber in Cycas[797]. The genus Stephanospermum (fig. 494, A)
illustrates the means by which the pollen-chamber was liberally supplied
with water and thus adapted to the requirements of fertilisation by motile
gametes. The pollen-chamber and its vascular supply paved the way for
siphonogamy, that is the development of a pollen-tube for the more direct
transmission of the male sperms. The highly developed mantle of tracheal
Page 343
tissue at the periphery of the nucellus in Stephanospermum, represented on
a reduced scale by the separate vascular strands of other seeds, may be
compared with the tracheal investment to the nucellus in the recent
Dicotyledonous genus Cassytha[798]. The presence of a nucellar vascular
system in several Palaeozoic seeds is a feature in which they differ from
those of recent Cycads with the exception of Bowenia. The retreat of the
vascular supply from the immediate neighbourhood of the pollen-chamber
in recent Cycads may, as Oliver points out, be correlated with the evolution
of the pollen-tube—the substitution of siphonogamy for zoidiogamy. The
diagram reproduced in fig. 492 represents a synthetic type based on such
seeds as Stephanospermum and Cardiocarpus which illustrate an
arrangement of conducting tissue frequently found in Palaeozoic seeds: the
main strand gives off a pair of bundles in the sarcotesta in the principal
plane, as in Cardiocarpus[799]; from the tracheal mass in the chalazal region
numerous bundles pass up the nucellus as far as the floor of the pollen-
chamber. The nature of the vascular supply in this generalised type and in
individual genera should be compared with that in the seeds of recent
Cycads[800] described in Chapter xxviii.
Recent research has revealed the not unexpected fact that in such Upper
Carboniferous petrified seeds as have been investigated—a small
proportion of the large number produced in the Palaeozoic forests—there
was a remarkable range in the mechanism connected with pollination and
the maturation of the microspores. A comparison of the genera Physostoma,
Lagenostoma, Conostoma, Trigonocarpus, Stephanospermum and others
reveals the occurrence of very different though not unrelated structural
features especially in the apical region of the seed. These seeds, including
Physostoma, probably the most archaic type, represent a stage in evolution
already far removed from the starting-point: the diversity of plan recalls the
variety in the form of the chloroplasts in the Green Algae, and in both cases
we are in touch with an experimental phase representing a tentative advance
towards greater efficiency.
In its differentiation into an outer fleshy region, the sarcotesta, a stony
layer, the sclerotesta, and in many cases an inner flesh, the Palaeozoic seeds
resemble recent Cycads: in both extinct and modern seeds the balance of
evidence would seem to be in favour of attributing a single rather than a
double origin to the integument.
a reduced scale by the separate vascular strands of other seeds, may be
compared with the tracheal investment to the nucellus in the recent
Dicotyledonous genus Cassytha[798]. The presence of a nucellar vascular
system in several Palaeozoic seeds is a feature in which they differ from
those of recent Cycads with the exception of Bowenia. The retreat of the
vascular supply from the immediate neighbourhood of the pollen-chamber
in recent Cycads may, as Oliver points out, be correlated with the evolution
of the pollen-tube—the substitution of siphonogamy for zoidiogamy. The
diagram reproduced in fig. 492 represents a synthetic type based on such
seeds as Stephanospermum and Cardiocarpus which illustrate an
arrangement of conducting tissue frequently found in Palaeozoic seeds: the
main strand gives off a pair of bundles in the sarcotesta in the principal
plane, as in Cardiocarpus[799]; from the tracheal mass in the chalazal region
numerous bundles pass up the nucellus as far as the floor of the pollen-
chamber. The nature of the vascular supply in this generalised type and in
individual genera should be compared with that in the seeds of recent
Cycads[800] described in Chapter xxviii.
Recent research has revealed the not unexpected fact that in such Upper
Carboniferous petrified seeds as have been investigated—a small
proportion of the large number produced in the Palaeozoic forests—there
was a remarkable range in the mechanism connected with pollination and
the maturation of the microspores. A comparison of the genera Physostoma,
Lagenostoma, Conostoma, Trigonocarpus, Stephanospermum and others
reveals the occurrence of very different though not unrelated structural
features especially in the apical region of the seed. These seeds, including
Physostoma, probably the most archaic type, represent a stage in evolution
already far removed from the starting-point: the diversity of plan recalls the
variety in the form of the chloroplasts in the Green Algae, and in both cases
we are in touch with an experimental phase representing a tentative advance
towards greater efficiency.
In its differentiation into an outer fleshy region, the sarcotesta, a stony
layer, the sclerotesta, and in many cases an inner flesh, the Palaeozoic seeds
resemble recent Cycads: in both extinct and modern seeds the balance of
evidence would seem to be in favour of attributing a single rather than a
double origin to the integument.
Page 344
Among the numerous types of Palaeozoic
seeds are several which invite comparison with
the fruits or carpels, apart from the seeds, of
Angiosperms. Impressions of Samaropsis seeds
(figs. 502, B–K; 503; 504) bear a close
resemblance to the laterally expanded fruits of
the common Crucifer Thlaspi arvense; the
ribbed testa of Hexagonocarpus (fig. 506, H)
and other genera recalls the fruit-wall of
Alstroemeria; the recently described Lower
Carboniferous seed Thysanotesta sagittula Fig. 492. ‘A conjectural
Nath. (fig. 506, F) simulates a carpel of synthetic type of seed
Erodium. These and similar instances of a close embodying the
parallelism in external features between organs characters of such a
that are not homologous, though in themselves seed as
of no morphological significance, are at least Stephanospermum with
interesting as illustrating the plasticity displayed those of a
by reproductive structures, which in the Cardiocarpus’; n,
Palaeozoic period marked a morphological nucellus; pc, pollen-
achievement comparable in its importance with chamber. (After
the still greater achievement represented by the Oliver.)
highly specialised fruits of the modern
Flowering plants. The range in form and surface-features of Angiospermous
fruits was foreshadowed by Palaeozoic seeds. Structural types and in some
cases, superadded to these, features which may reasonably be supposed to
have facilitated dispersal had been acquired by the seeds of Palaeozoic
plants in forms that in a much later period were adopted by fruits even to a
greater degree than by seeds. Characters useful in seed-dispersal, that are
now shared by fruits and seeds, are illustrated by the fleshy and possibly
edible seeds of extinct Gymnosperms, the plumes and hairy beak of
Gnetopsis (fig. 494, E) and Thysanotesta (fig. 506, F) suggestive of feathery
stigmas and other appendages. The lacunar sarcotesta of Aetheotesta, the
thick endotesta of Pachytesta (fig. 497), and the air-chamber of
Codonospermum (fig. 498), are strictly comparable with aids to buoyancy
in fruits of existing Flowering plants. The mucilage-hairs and superficial
cells in Physostoma (fig. 494, I) and Stephanospermum may be compared
seeds are several which invite comparison with
the fruits or carpels, apart from the seeds, of
Angiosperms. Impressions of Samaropsis seeds
(figs. 502, B–K; 503; 504) bear a close
resemblance to the laterally expanded fruits of
the common Crucifer Thlaspi arvense; the
ribbed testa of Hexagonocarpus (fig. 506, H)
and other genera recalls the fruit-wall of
Alstroemeria; the recently described Lower
Carboniferous seed Thysanotesta sagittula Fig. 492. ‘A conjectural
Nath. (fig. 506, F) simulates a carpel of synthetic type of seed
Erodium. These and similar instances of a close embodying the
parallelism in external features between organs characters of such a
that are not homologous, though in themselves seed as
of no morphological significance, are at least Stephanospermum with
interesting as illustrating the plasticity displayed those of a
by reproductive structures, which in the Cardiocarpus’; n,
Palaeozoic period marked a morphological nucellus; pc, pollen-
achievement comparable in its importance with chamber. (After
the still greater achievement represented by the Oliver.)
highly specialised fruits of the modern
Flowering plants. The range in form and surface-features of Angiospermous
fruits was foreshadowed by Palaeozoic seeds. Structural types and in some
cases, superadded to these, features which may reasonably be supposed to
have facilitated dispersal had been acquired by the seeds of Palaeozoic
plants in forms that in a much later period were adopted by fruits even to a
greater degree than by seeds. Characters useful in seed-dispersal, that are
now shared by fruits and seeds, are illustrated by the fleshy and possibly
edible seeds of extinct Gymnosperms, the plumes and hairy beak of
Gnetopsis (fig. 494, E) and Thysanotesta (fig. 506, F) suggestive of feathery
stigmas and other appendages. The lacunar sarcotesta of Aetheotesta, the
thick endotesta of Pachytesta (fig. 497), and the air-chamber of
Codonospermum (fig. 498), are strictly comparable with aids to buoyancy
in fruits of existing Flowering plants. The mucilage-hairs and superficial
cells in Physostoma (fig. 494, I) and Stephanospermum may be compared
Page 345
with the thick mucilaginous investment of the megaspores of recent water-
ferns and with similar tissues of some Angiospermous seeds.
The bionomics of Palaeozoic plants is a subject worthy of more serious
attention than it has so far received. The search for morphological
characters that may have facilitated the wanderings of widely distributed
genera and species and a closer investigation of physiological-anatomical
problems presented by the vegetative organs of petrified plants would not
only extend our knowledge of the morphology of ancient types but would
stimulate comparative study and, incidentally, relieve the dullness of pure
description. It may be argued that we should first establish a more solid
foundation by further observations on living plants; but even at the risk of
allowing speculation too free a hand the attempt is worth making, and it
may be urged that, as in phylogenetic enquiries so in other branches of
botany, facts obtained from plants of other ages may serve to supply
deficiencies in knowledge based only on existing forms. One of the
difficulties inseparable from the study of fossil plants, namely the
identification of impressions and casts with specimens exhibiting
anatomical characters, is particularly well illustrated by seeds. The
description of a genus based on mere external form may sometimes be
extended without great risk of error to include species founded on
anatomical characters, but on the other hand, there are many instances in
which—despite a general resemblance in form and size between
petrifactions and impressions—lack of evidence of generic identity requires
the employment of distinctive names. The determination of impressions is,
as Lesquereux recognised, ‘subject to a great deal of uncertainty,’ and many
of the genera founded on external features are purely artificial and include
species that have no essential features in common. Moreover in the case of
petrified specimens the apparent absence of an external fleshy layer is often
due to destruction before preservation: as Solms-Laubach[801] points out, it is
obviously impossible to be certain as to the number of integumental layers
in seeds that are not well preserved in all their parts. Goeppert founded a
new genus, Acanthocarpus, on a Permian seed described as A.
xanthioides[802], because of the occurrence of spinous processes attached to
an obcordate kernel: these apparent spines are in all probability the remains
of a very imperfectly preserved sarcotesta. The preservation of the central
portion of a seed, that is the seed-cavity with the enclosing shell,
conveniently called the nucule, has often led to an unnecessary
ferns and with similar tissues of some Angiospermous seeds.
The bionomics of Palaeozoic plants is a subject worthy of more serious
attention than it has so far received. The search for morphological
characters that may have facilitated the wanderings of widely distributed
genera and species and a closer investigation of physiological-anatomical
problems presented by the vegetative organs of petrified plants would not
only extend our knowledge of the morphology of ancient types but would
stimulate comparative study and, incidentally, relieve the dullness of pure
description. It may be argued that we should first establish a more solid
foundation by further observations on living plants; but even at the risk of
allowing speculation too free a hand the attempt is worth making, and it
may be urged that, as in phylogenetic enquiries so in other branches of
botany, facts obtained from plants of other ages may serve to supply
deficiencies in knowledge based only on existing forms. One of the
difficulties inseparable from the study of fossil plants, namely the
identification of impressions and casts with specimens exhibiting
anatomical characters, is particularly well illustrated by seeds. The
description of a genus based on mere external form may sometimes be
extended without great risk of error to include species founded on
anatomical characters, but on the other hand, there are many instances in
which—despite a general resemblance in form and size between
petrifactions and impressions—lack of evidence of generic identity requires
the employment of distinctive names. The determination of impressions is,
as Lesquereux recognised, ‘subject to a great deal of uncertainty,’ and many
of the genera founded on external features are purely artificial and include
species that have no essential features in common. Moreover in the case of
petrified specimens the apparent absence of an external fleshy layer is often
due to destruction before preservation: as Solms-Laubach[801] points out, it is
obviously impossible to be certain as to the number of integumental layers
in seeds that are not well preserved in all their parts. Goeppert founded a
new genus, Acanthocarpus, on a Permian seed described as A.
xanthioides[802], because of the occurrence of spinous processes attached to
an obcordate kernel: these apparent spines are in all probability the remains
of a very imperfectly preserved sarcotesta. The preservation of the central
portion of a seed, that is the seed-cavity with the enclosing shell,
conveniently called the nucule, has often led to an unnecessary
Page 346
multiplication of generic terms. Other examples of confusion resulting from
different states of preservation are quoted in the accounts of some of the
selected types.
Williamson in 1877 pointed out that we learn from the large number of
different kinds of Palaeozoic seeds that ‘there were in the Carboniferous
forests many gymnospermous stems clothed with foliage of which we have
not yet discovered any traces, probably because these Gymnosperms did not
flourish upon the low swampy grounds which were the homes of the great
mass of the coal-producing plants[803].’ Prof. Zeiller[804] has also drawn
attention to the numerical excess of seeds over vegetative organs. This
discrepancy has to a large extent been explained by the discovery that many
of the supposed Ferns were seed-bearing plants, and a further explanation is
suggested by the superiority of seeds over stems and leaves in their
adaptation to dispersal by water.
In 1874 Brongniart[805] described several petrified seeds from material
discovered by Grand’Eury in the St Étienne coal-field, and seven years later
his descriptions were republished[806], with the addition of several
beautifully executed drawings, as a posthumous volume edited by his
distinguished pupil Renault. Williamson’s researches supplied much
additional information, and in recent years the more detailed study of
French and English seeds by Bertrand and particularly by Oliver and his
pupils has further emphasised the interest and importance of this field of
work. Brongniart proposed a two-fold classification of French seeds: (i)
bilaterally symmetrical seeds, more or less flattened in section, which he
believed to be Cordaitean; (ii) radially symmetrical seeds, circular in
transverse section: the latter group he considered to be less closely allied to
recent types. The employment of the terms Platyspermeae and
Radiospermeae, proposed by Oliver[807] for Brongniart’s divisions, serves a
useful purpose if due regard is paid to the adequacy of the evidence as to
symmetry and if it is recognised that this classification cannot be rigidly
employed in all cases. It was pointed out by Brongniart that the occasional
occurrence of tricarinate seeds of Ginkgo (fig. 631) and Taxus is an
exception to the general rule of bilateral symmetry: seeds of Cycas are
normally bilateral, but radially symmetrical forms also occur[808]. The genus
Conostoma (fig. 494, B) represents an intermediate type which, though
almost radially symmetrical, exhibits a slight tendency towards
different states of preservation are quoted in the accounts of some of the
selected types.
Williamson in 1877 pointed out that we learn from the large number of
different kinds of Palaeozoic seeds that ‘there were in the Carboniferous
forests many gymnospermous stems clothed with foliage of which we have
not yet discovered any traces, probably because these Gymnosperms did not
flourish upon the low swampy grounds which were the homes of the great
mass of the coal-producing plants[803].’ Prof. Zeiller[804] has also drawn
attention to the numerical excess of seeds over vegetative organs. This
discrepancy has to a large extent been explained by the discovery that many
of the supposed Ferns were seed-bearing plants, and a further explanation is
suggested by the superiority of seeds over stems and leaves in their
adaptation to dispersal by water.
In 1874 Brongniart[805] described several petrified seeds from material
discovered by Grand’Eury in the St Étienne coal-field, and seven years later
his descriptions were republished[806], with the addition of several
beautifully executed drawings, as a posthumous volume edited by his
distinguished pupil Renault. Williamson’s researches supplied much
additional information, and in recent years the more detailed study of
French and English seeds by Bertrand and particularly by Oliver and his
pupils has further emphasised the interest and importance of this field of
work. Brongniart proposed a two-fold classification of French seeds: (i)
bilaterally symmetrical seeds, more or less flattened in section, which he
believed to be Cordaitean; (ii) radially symmetrical seeds, circular in
transverse section: the latter group he considered to be less closely allied to
recent types. The employment of the terms Platyspermeae and
Radiospermeae, proposed by Oliver[807] for Brongniart’s divisions, serves a
useful purpose if due regard is paid to the adequacy of the evidence as to
symmetry and if it is recognised that this classification cannot be rigidly
employed in all cases. It was pointed out by Brongniart that the occasional
occurrence of tricarinate seeds of Ginkgo (fig. 631) and Taxus is an
exception to the general rule of bilateral symmetry: seeds of Cycas are
normally bilateral, but radially symmetrical forms also occur[808]. The genus
Conostoma (fig. 494, B) represents an intermediate type which, though
almost radially symmetrical, exhibits a slight tendency towards
Page 347
platyspermy. Evidence recently brought forward by Nathorst[809] renders
probable a connexion of a presumably radiospermic seed Lagenospermum
Arberi[810] with the Lower Carboniferous fronds Adiantites bellidulus Heer,
and this furnishes an interesting illustration of the association of both
platyspermic and radiospermic seeds with the same generic type of foliage.
While retaining Radiosperm and Platysperm as convenient descriptive
terms, I have not adopted them as group-designations on the ground that
they do not in themselves serve as trustworthy criteria of relationship.
Attention is called by Salisbury[811] to the occurrence of bilaterally and
radially symmetrical fruits among British Carices and to a similar mixture
in the family Polygonaceae.
The acquisition of more detailed and accurate knowledge of Palaeozoic
seeds led to an extension of the two-fold division of Brongniart and Oliver
which is based on such characters as the position of the vascular tissue in
relation to the integument and nucellus, the form of the pollen-chamber, and
other features. The division Lagenostomales has been instituted for
Lagenostoma and some other Radiosperms connected by certain important
characters: these seeds may be referred to the Pteridospermeae though it is
only in the case of Lagenostoma, and to a less extent Sphaerostoma, that a
correlation between vegetative organs and seeds has been rendered
sufficiently probable to justify an assumption of generic identity. The name
Trigonocarpeae[812] has recently been used for a section of Radiosperms
represented by Trigonocarpus, Stephanospermum, and other genera.
Although the genus Stephanospermum, as Oliver[813] says, may be regarded
as the type-genus of a group of seeds, it is more fitting, as the same
author[814] insists, to adopt a divisional term based on the generic name of
the much more widely spread and more familiar Trigonocarpus. For the
sake of uniformity in nomenclature it is proposed to adopt the name
Trigonocarpales instead of Trigonocarpeae to rank with Lagenostomales.
The Platyspermeae comprise such seeds as Cardiocarpus,
Mitrospermum, and Rhabdospermum, genera characterised by well-marked
anatomical features and probably Cordaitean; it has, however, been shown
that typical Platysperms were also borne on leaves of Pteridosperms and, as
Mrs Arber[815] says, the notion that every member of the Platyspermeae was
necessarily a Cordaitean seed has been discredited by the discovery of the
seeds of Aneimites (Wardia) and Pecopteris Pluckeneti[816]. For general
probable a connexion of a presumably radiospermic seed Lagenospermum
Arberi[810] with the Lower Carboniferous fronds Adiantites bellidulus Heer,
and this furnishes an interesting illustration of the association of both
platyspermic and radiospermic seeds with the same generic type of foliage.
While retaining Radiosperm and Platysperm as convenient descriptive
terms, I have not adopted them as group-designations on the ground that
they do not in themselves serve as trustworthy criteria of relationship.
Attention is called by Salisbury[811] to the occurrence of bilaterally and
radially symmetrical fruits among British Carices and to a similar mixture
in the family Polygonaceae.
The acquisition of more detailed and accurate knowledge of Palaeozoic
seeds led to an extension of the two-fold division of Brongniart and Oliver
which is based on such characters as the position of the vascular tissue in
relation to the integument and nucellus, the form of the pollen-chamber, and
other features. The division Lagenostomales has been instituted for
Lagenostoma and some other Radiosperms connected by certain important
characters: these seeds may be referred to the Pteridospermeae though it is
only in the case of Lagenostoma, and to a less extent Sphaerostoma, that a
correlation between vegetative organs and seeds has been rendered
sufficiently probable to justify an assumption of generic identity. The name
Trigonocarpeae[812] has recently been used for a section of Radiosperms
represented by Trigonocarpus, Stephanospermum, and other genera.
Although the genus Stephanospermum, as Oliver[813] says, may be regarded
as the type-genus of a group of seeds, it is more fitting, as the same
author[814] insists, to adopt a divisional term based on the generic name of
the much more widely spread and more familiar Trigonocarpus. For the
sake of uniformity in nomenclature it is proposed to adopt the name
Trigonocarpales instead of Trigonocarpeae to rank with Lagenostomales.
The Platyspermeae comprise such seeds as Cardiocarpus,
Mitrospermum, and Rhabdospermum, genera characterised by well-marked
anatomical features and probably Cordaitean; it has, however, been shown
that typical Platysperms were also borne on leaves of Pteridosperms and, as
Mrs Arber[815] says, the notion that every member of the Platyspermeae was
necessarily a Cordaitean seed has been discredited by the discovery of the
seeds of Aneimites (Wardia) and Pecopteris Pluckeneti[816]. For general
Page 348
purposes it is hardly necessary to adopt the subdivisions of the
Lagenostomales used by Oliver and Salisbury[817], though as facts
accumulate we shall no doubt be able to make further advances towards a
natural system of classification. The following three divisions of Permo-
Carboniferous seeds include genera founded on petrified specimens and
thus afford valuable morphological data. The groups Lagenostomales and
Trigonocarpales include types belonging to closely related plants, a
relationship clearly expressed in the seed-characters.
I. Lagenostomales.
The seeds included in this group are for the most part Radiosperms, but
in its slightly developed bilateral symmetry Conostoma oblongum is a type
transitional between Radiosperms and Platysperms. The testa may be ribbed
and the ribs vary in number. The nucellus (megasporangium) is united to
the integument not only at the base but laterally as far as the shoulder of the
seed up to a level corresponding to the base of the pollen-chamber
(lagenostome) as in all recent Cycads and in the majority of Conifers. The
seeds proper apart from the cupule are supplied with a single set of vascular
bundles; there is no vascular tissue in the nucellus, a feature no doubt
correlated with the fusion of nucellus and integument[818]. The free portion
of the integument is more or less deeply lobed or, in Lagenostoma, it forms
a pyramidal canopy of fused lobes enclosing the lagenostome. The presence
of a tapetal zone surrounding the megaspore is believed to be a feature
characteristic of the group[819]. The testa, wholly or partially ribbed, is
relatively thinner than in the Trigonocarpales and Cardiocarpales, and in its
differentiation agrees less closely with the testa of recent Cycadean seeds.
In Lagenostoma and possibly in other genera a loose sheath or cupule
surrounded the ovule, while in Gnetopsis a similar envelope enclosed two
to four seeds.
The microspores are multicellular and smaller than those of
Trigonocarpales, the average dimensions (Conostoma, Physostoma,
Lagenostoma) being 67μ × 52μ.
Genera. Physostoma; Conostoma; Sphaerostoma; Lagenostoma;
Gnetopsis.
Lagenostomales used by Oliver and Salisbury[817], though as facts
accumulate we shall no doubt be able to make further advances towards a
natural system of classification. The following three divisions of Permo-
Carboniferous seeds include genera founded on petrified specimens and
thus afford valuable morphological data. The groups Lagenostomales and
Trigonocarpales include types belonging to closely related plants, a
relationship clearly expressed in the seed-characters.
I. Lagenostomales.
The seeds included in this group are for the most part Radiosperms, but
in its slightly developed bilateral symmetry Conostoma oblongum is a type
transitional between Radiosperms and Platysperms. The testa may be ribbed
and the ribs vary in number. The nucellus (megasporangium) is united to
the integument not only at the base but laterally as far as the shoulder of the
seed up to a level corresponding to the base of the pollen-chamber
(lagenostome) as in all recent Cycads and in the majority of Conifers. The
seeds proper apart from the cupule are supplied with a single set of vascular
bundles; there is no vascular tissue in the nucellus, a feature no doubt
correlated with the fusion of nucellus and integument[818]. The free portion
of the integument is more or less deeply lobed or, in Lagenostoma, it forms
a pyramidal canopy of fused lobes enclosing the lagenostome. The presence
of a tapetal zone surrounding the megaspore is believed to be a feature
characteristic of the group[819]. The testa, wholly or partially ribbed, is
relatively thinner than in the Trigonocarpales and Cardiocarpales, and in its
differentiation agrees less closely with the testa of recent Cycadean seeds.
In Lagenostoma and possibly in other genera a loose sheath or cupule
surrounded the ovule, while in Gnetopsis a similar envelope enclosed two
to four seeds.
The microspores are multicellular and smaller than those of
Trigonocarpales, the average dimensions (Conostoma, Physostoma,
Lagenostoma) being 67μ × 52μ.
Genera. Physostoma; Conostoma; Sphaerostoma; Lagenostoma;
Gnetopsis.
Page 349
Lagenostoma may safely be referred to Lyginopteris, and Sphaerostoma
with but little risk of error to Heterangium: the parent-plants of the other
genera are unknown, but all may be regarded as the seeds of Pteridosperms
and probably of genera more nearly allied to the Lyginopterideae than to the
Medulloseae. The genus Lagenospermum, recently instituted by
Nathorst[820], is dealt with in Chapter xxxi.
Physostoma. Williamson.
Physostoma elegans Williamson.
The generic name Physostoma[821] was applied by Williamson[822] to a
seed from the Lower Coal Measures of Lancashire which he named P.
elegans; he afterwards described it as Lagenostoma physoides, but the
original name has been revived by Oliver[823] to whom our knowledge of
this type is chiefly due. The specimens figured by Williamson[824] as
Sporocarpon ornatum also belong to Physostoma elegans. The seeds are
circular in section, approximately 6 mm. long with a maximum diameter of
2 mm. The testa has about 10 longitudinal ribs passing in the apical region
into a ring of free lobes or tentacles surrounding and considerably
overtopping the nucellar apex: these tentacles take the place of a micropylar
tube (fig. 494, I; fig. 493, D) and are a feature ‘in which this seed differs
from all other known seeds, fossil or recent[825].’ A single vascular strand
passes through the chalazal region and divides into 10 bundles, one to each
rib and tentacle. The single integument consists of a few layers of cells,
those of the epidermis being prolonged into clavate mucilaginous hairs, fig.
494, I, h, that may reach a length of ·5 mm. and in the living seed almost
covered the whole surface of the testa, being especially long on the ribs and
tentacles. There is no special development of sclerous tissue, the vascular
bundles, v, being embedded in parenchyma in the inner portion of the
integument. The nucellus is represented by a zone rich in secretory cells,
and internal to this is a tapetum. Integument and nucellus are coalescent up
to the apical region where the former splits into 10 tentacles. The nucellar
apex has the form of a tall dome surrounded by a bell-shaped pollen-
chamber (fig. 494, I, pc; fig. 493, C, D, c) into which it projects like the
base of a wine-bottle. The circular opening of the pollen-chamber overtops
the roof of the dome formed of the secretory tissue of the nucellus and the
with but little risk of error to Heterangium: the parent-plants of the other
genera are unknown, but all may be regarded as the seeds of Pteridosperms
and probably of genera more nearly allied to the Lyginopterideae than to the
Medulloseae. The genus Lagenospermum, recently instituted by
Nathorst[820], is dealt with in Chapter xxxi.
Physostoma. Williamson.
Physostoma elegans Williamson.
The generic name Physostoma[821] was applied by Williamson[822] to a
seed from the Lower Coal Measures of Lancashire which he named P.
elegans; he afterwards described it as Lagenostoma physoides, but the
original name has been revived by Oliver[823] to whom our knowledge of
this type is chiefly due. The specimens figured by Williamson[824] as
Sporocarpon ornatum also belong to Physostoma elegans. The seeds are
circular in section, approximately 6 mm. long with a maximum diameter of
2 mm. The testa has about 10 longitudinal ribs passing in the apical region
into a ring of free lobes or tentacles surrounding and considerably
overtopping the nucellar apex: these tentacles take the place of a micropylar
tube (fig. 494, I; fig. 493, D) and are a feature ‘in which this seed differs
from all other known seeds, fossil or recent[825].’ A single vascular strand
passes through the chalazal region and divides into 10 bundles, one to each
rib and tentacle. The single integument consists of a few layers of cells,
those of the epidermis being prolonged into clavate mucilaginous hairs, fig.
494, I, h, that may reach a length of ·5 mm. and in the living seed almost
covered the whole surface of the testa, being especially long on the ribs and
tentacles. There is no special development of sclerous tissue, the vascular
bundles, v, being embedded in parenchyma in the inner portion of the
integument. The nucellus is represented by a zone rich in secretory cells,
and internal to this is a tapetum. Integument and nucellus are coalescent up
to the apical region where the former splits into 10 tentacles. The nucellar
apex has the form of a tall dome surrounded by a bell-shaped pollen-
chamber (fig. 494, I, pc; fig. 493, C, D, c) into which it projects like the
base of a wine-bottle. The circular opening of the pollen-chamber overtops
the roof of the dome formed of the secretory tissue of the nucellus and the
Page 350
carbonised remains of the tapetum: this dark band surrounds the large
megaspore-cavity (fig. 494, I). Physostoma is the only member of the
Lagenostomales in which the megaspore projects into the free nucellar
apex: in other genera intercalary growth has produced a more or less
prominent plinth, the name given to the free portion of the nucellus between
the megaspore and the pollen-chamber. Williamson[826] described the
mammillated apex of the nucellus as pushed up into the base of the
lagenostome which ‘looks like a bladder half full of fluid resting upon and
overhanging the end of a soda-water bottle’: it was this appearance that
suggested the name Physostoma. The section reproduced in fig. 493, D,
shows in the centre the limiting tissue of the nucellus surrounded by the
pollen-chamber, c, and external to this are the tentacles with their groups of
long hairs: the vascular bundles are represented by spaces in the more
internal small-celled tissue (see also fig. 494, I). A characteristic feature is
the presence of a tapetum or megaspore-jacket[827] in the nucellus:
immediately internal to the vascular bundles stretching from the chalaza to
the apex of the megaspore-cavity is a layer of delicate cells with secretory
sacs, and this is succeeded by a broad black layer of rather larger cells, a
tissue which was probably in full activity in a younger stage of
development.
megaspore-cavity (fig. 494, I). Physostoma is the only member of the
Lagenostomales in which the megaspore projects into the free nucellar
apex: in other genera intercalary growth has produced a more or less
prominent plinth, the name given to the free portion of the nucellus between
the megaspore and the pollen-chamber. Williamson[826] described the
mammillated apex of the nucellus as pushed up into the base of the
lagenostome which ‘looks like a bladder half full of fluid resting upon and
overhanging the end of a soda-water bottle’: it was this appearance that
suggested the name Physostoma. The section reproduced in fig. 493, D,
shows in the centre the limiting tissue of the nucellus surrounded by the
pollen-chamber, c, and external to this are the tentacles with their groups of
long hairs: the vascular bundles are represented by spaces in the more
internal small-celled tissue (see also fig. 494, I). A characteristic feature is
the presence of a tapetum or megaspore-jacket[827] in the nucellus:
immediately internal to the vascular bundles stretching from the chalaza to
the apex of the megaspore-cavity is a layer of delicate cells with secretory
sacs, and this is succeeded by a broad black layer of rather larger cells, a
tissue which was probably in full activity in a younger stage of
development.
Page 351
Fig. 493. A, Lagenostoma ovoides, longitudinal section of the
lagenostome. B, Lagenostoma Lomaxi, transverse section of the
lagenostome and canopy; c, pollen-chamber; d, space between the
nucellus and integument. (A, after Miss Prankerd; B, from a
section in the Manchester Museum, R 1048.) C, Physostoma
elegans, longitudinal section showing microspores in the pollen-
chamber, c. (From a section in the University College Collection.)
D, Physostoma elegans, transverse section of the apical region
showing the tentacles, pollen-chamber, c, etc. E, Telangium Scotti,
transverse section of sporangia (Manchester Coll. R 1047). F, G,
Stephanospermum akenioides. F, section of sclerotesta. G, tracheids
from the nucellus. (University College Coll.)
A comparable tapetal layer is described by Lang[828] in the ovule of
Stangeria: the majority of the sporogenous cells surrounding the megaspore
become disintegrated and are absorbed, but the outermost zone forms a
more definite tapetal layer: as already suggested, this tissue in Physostoma
may be a group-character. No archegonia have been found, but in a few
lagenostome. B, Lagenostoma Lomaxi, transverse section of the
lagenostome and canopy; c, pollen-chamber; d, space between the
nucellus and integument. (A, after Miss Prankerd; B, from a
section in the Manchester Museum, R 1048.) C, Physostoma
elegans, longitudinal section showing microspores in the pollen-
chamber, c. (From a section in the University College Collection.)
D, Physostoma elegans, transverse section of the apical region
showing the tentacles, pollen-chamber, c, etc. E, Telangium Scotti,
transverse section of sporangia (Manchester Coll. R 1047). F, G,
Stephanospermum akenioides. F, section of sclerotesta. G, tracheids
from the nucellus. (University College Coll.)
A comparable tapetal layer is described by Lang[828] in the ovule of
Stangeria: the majority of the sporogenous cells surrounding the megaspore
become disintegrated and are absorbed, but the outermost zone forms a
more definite tapetal layer: as already suggested, this tissue in Physostoma
may be a group-character. No archegonia have been found, but in a few
Page 352
cases some of the delicate prothallus-tissue occurs in the interior of the
seed. Microspores are often abundant in the pollen-chamber (fig. 493, C, c);
in one seed 80 are recorded. The occurrence of so many microspores
suggested to Oliver that insect-agency may have been responsible for the
precision in pollination that is greater than one would expect in
anemophilous plants. The spores are smaller than those of Lagenostoma
(55μ × 45μ) and in several of them the remains of a cellular tissue are
preserved (fig. 494, N), also some sub-reniform bodies (fig. 494, M) similar
to those described as spermatozoids by Dr Benson in Lagenostoma (fig.
408, D).
The most interesting features of Physostoma are: the absence of a
continuous micropylar tube and its replacement by a circle of integumental
lobes; the apical prolongation of the nucellar apex into the pollen-chamber,
and the presence of long mucilaginous hairs on the integument. The large
pollen-chamber is a character which distinguishes Physostoma from
Conostoma and its form is very different from that in Lagenostoma.
The tentacles of the integument and the form of the nucellar apex are
features consistent with Oliver’s view that Physostoma is the most primitive
of Palaeozoic seeds though, as Burlingame[829] says, the elaborate form of
the encasing envelope marks a considerable advance beyond the earliest
type of megasporangium integument.
A new type of Physostoma has been briefly described by Gordon[830],
without a specific designation, from the Lower Carboniferous beds of
Pettycur (Fife): it was found in association with Heterangium and
Sphaerostoma ovale.
We have no knowledge of the plant to which Physostoma belonged, but
the general plan of organisation of the seed points to a near relationship to
Lagenostoma and presumably, as regards the parent-plant, to a genus
related to Lyginopteris.
Conostoma. Williamson.
This name[831], suggested by the funnel-like pollen-chamber or
lagenostome, was applied by Williamson[832] to some seeds from the Lower
Coal Measures of Lancashire and Yorkshire and from the Lower
seed. Microspores are often abundant in the pollen-chamber (fig. 493, C, c);
in one seed 80 are recorded. The occurrence of so many microspores
suggested to Oliver that insect-agency may have been responsible for the
precision in pollination that is greater than one would expect in
anemophilous plants. The spores are smaller than those of Lagenostoma
(55μ × 45μ) and in several of them the remains of a cellular tissue are
preserved (fig. 494, N), also some sub-reniform bodies (fig. 494, M) similar
to those described as spermatozoids by Dr Benson in Lagenostoma (fig.
408, D).
The most interesting features of Physostoma are: the absence of a
continuous micropylar tube and its replacement by a circle of integumental
lobes; the apical prolongation of the nucellar apex into the pollen-chamber,
and the presence of long mucilaginous hairs on the integument. The large
pollen-chamber is a character which distinguishes Physostoma from
Conostoma and its form is very different from that in Lagenostoma.
The tentacles of the integument and the form of the nucellar apex are
features consistent with Oliver’s view that Physostoma is the most primitive
of Palaeozoic seeds though, as Burlingame[829] says, the elaborate form of
the encasing envelope marks a considerable advance beyond the earliest
type of megasporangium integument.
A new type of Physostoma has been briefly described by Gordon[830],
without a specific designation, from the Lower Carboniferous beds of
Pettycur (Fife): it was found in association with Heterangium and
Sphaerostoma ovale.
We have no knowledge of the plant to which Physostoma belonged, but
the general plan of organisation of the seed points to a near relationship to
Lagenostoma and presumably, as regards the parent-plant, to a genus
related to Lyginopteris.
Conostoma. Williamson.
This name[831], suggested by the funnel-like pollen-chamber or
lagenostome, was applied by Williamson[832] to some seeds from the Lower
Coal Measures of Lancashire and Yorkshire and from the Lower
Page 353
Carboniferous beds of Burntisland. The Burntisland seeds, referred by
Williamson to two species, have recently been united and described by Miss
Benson as Sphaerostoma ovale[833]. The English species has been
thoroughly investigated by Oliver and Salisbury[834] who have also
described a second species, C. anglo-germanicum, from the Coal Measures
of Lancashire and Germany.
Conostoma oblongum Williamson.
This rare type is represented by approximately cylindrical seeds with an
average length of 5 mm. and a maximum breadth of 2·3 mm. borne on a
relatively stout stalk and tapering to a blunt apex characterised by a canopy
of six short lobes (fig. 494, B, C) in marked contrast to the long tentacles of
Physostoma. In the basal region the integument has six prominent ribs
which soon die out when traced upwards: a transverse section through the
body of the seed is hexagonal (fig. 494, D), the angles corresponding to the
basal ribs, and there is a slight tendency to platyspermy. The testa has an
epidermal mucilaginous layer which becomes exfoliated through the lifting-
up of the cuticle by the underlying mucilage: below this, at the apex of the
seed, is a cap of fleshy tissue (fig. 494, B, sa) which, it is suggested, may
have had a secretory function in connexion with a drop-mechanism in
pollination like that in recent Conifers. No microspores have been found in
the pollen-chamber. The epidermis, called by Oliver and Salisbury the
blow-off layer (fig. 494, B, m), together with the cap of soft tissue
constitute a feebly developed sarcotesta. A sclerotesta consisting of a
palisade-layer and a fibrous hypoderm extends over the main body of the
seed below the epidermis; it forms the basal ribs and increases considerably
in breadth at the apical region to form a sclerous cone penetrated by six
strands of parenchyma enclosing vascular bundles (fig. 494, D) which pass
up from the conducting tissue immediately external to the nucellus. The
nucellus is coalescent with the integument, as in Physostoma, as far as the
level of the domical free apex of the nucellus where the tapetal tissue that
lines the seed-cavity passes across the almost flat top of the central region
originally occupied by the megaspore. In some sections prothallus-tissue
was found with an apical ‘tent-pole’ protuberance. A striking feature of
Conostoma is the mechanism for the reception of the microspores. The free
part of the nucellus consists of the plinth, a broad tapering region originally
filled with parenchyma but in most cases represented only by its epidermis:
Williamson to two species, have recently been united and described by Miss
Benson as Sphaerostoma ovale[833]. The English species has been
thoroughly investigated by Oliver and Salisbury[834] who have also
described a second species, C. anglo-germanicum, from the Coal Measures
of Lancashire and Germany.
Conostoma oblongum Williamson.
This rare type is represented by approximately cylindrical seeds with an
average length of 5 mm. and a maximum breadth of 2·3 mm. borne on a
relatively stout stalk and tapering to a blunt apex characterised by a canopy
of six short lobes (fig. 494, B, C) in marked contrast to the long tentacles of
Physostoma. In the basal region the integument has six prominent ribs
which soon die out when traced upwards: a transverse section through the
body of the seed is hexagonal (fig. 494, D), the angles corresponding to the
basal ribs, and there is a slight tendency to platyspermy. The testa has an
epidermal mucilaginous layer which becomes exfoliated through the lifting-
up of the cuticle by the underlying mucilage: below this, at the apex of the
seed, is a cap of fleshy tissue (fig. 494, B, sa) which, it is suggested, may
have had a secretory function in connexion with a drop-mechanism in
pollination like that in recent Conifers. No microspores have been found in
the pollen-chamber. The epidermis, called by Oliver and Salisbury the
blow-off layer (fig. 494, B, m), together with the cap of soft tissue
constitute a feebly developed sarcotesta. A sclerotesta consisting of a
palisade-layer and a fibrous hypoderm extends over the main body of the
seed below the epidermis; it forms the basal ribs and increases considerably
in breadth at the apical region to form a sclerous cone penetrated by six
strands of parenchyma enclosing vascular bundles (fig. 494, D) which pass
up from the conducting tissue immediately external to the nucellus. The
nucellus is coalescent with the integument, as in Physostoma, as far as the
level of the domical free apex of the nucellus where the tapetal tissue that
lines the seed-cavity passes across the almost flat top of the central region
originally occupied by the megaspore. In some sections prothallus-tissue
was found with an apical ‘tent-pole’ protuberance. A striking feature of
Conostoma is the mechanism for the reception of the microspores. The free
part of the nucellus consists of the plinth, a broad tapering region originally
filled with parenchyma but in most cases represented only by its epidermis:
Page 354
the plinth, p, is seen in fig. 494, B, to be two-storeyed, the upper and
narrower storey being a space formerly filled by a pad of tissue suspended
from the floor of the superposed lagenostome (pollen-chamber)[835]. The
greater development of the domical plinth is a feature in which Conostoma
differs from Physostoma. At the apex of the plinth and resting on a slight
depression is a small lagenostome, bowl-shaped in section, and like the
pollen-chamber of Lagenostoma, formed as the result of enzyme-action on
the apical papilla of the nucellus (fig. 494, B, B′, l′). The mouth of the
lagenostome engages with the micropylar tube by a projecting flange (fig.
494, B′, f) of tissue lining the micropylar canal and by a second flange (f′) at
the base of the lagenostome where the roof of the plinth (fig. 494, B′, p)
bends downwards and inwards. The walls of the lagenostome are formed by
strong cells with thickening bands giving them the appearance of tracheids
(l′), but the floor of the lagenostome is made of thinner cells which become
disorganised, allowing the microspores to fall into the large plinth-cavity
below (p, fig. 494, B), an arrangement comparable with the two-storeyed
pollen-chamber of Bowenia[836] and, to a less extent, with the micropyle of
the Conifer Tsuga. The microspores are multicellular and ellipsoidal
measuring 75μ × 65μ.
narrower storey being a space formerly filled by a pad of tissue suspended
from the floor of the superposed lagenostome (pollen-chamber)[835]. The
greater development of the domical plinth is a feature in which Conostoma
differs from Physostoma. At the apex of the plinth and resting on a slight
depression is a small lagenostome, bowl-shaped in section, and like the
pollen-chamber of Lagenostoma, formed as the result of enzyme-action on
the apical papilla of the nucellus (fig. 494, B, B′, l′). The mouth of the
lagenostome engages with the micropylar tube by a projecting flange (fig.
494, B′, f) of tissue lining the micropylar canal and by a second flange (f′) at
the base of the lagenostome where the roof of the plinth (fig. 494, B′, p)
bends downwards and inwards. The walls of the lagenostome are formed by
strong cells with thickening bands giving them the appearance of tracheids
(l′), but the floor of the lagenostome is made of thinner cells which become
disorganised, allowing the microspores to fall into the large plinth-cavity
below (p, fig. 494, B), an arrangement comparable with the two-storeyed
pollen-chamber of Bowenia[836] and, to a less extent, with the micropyle of
the Conifer Tsuga. The microspores are multicellular and ellipsoidal
measuring 75μ × 65μ.
Page 355
Fig. 494. A, Stephanospermum akenioides; s, space between integument
and nucellus; n, nucellus; e, inner part of testa; sc, sclerotesta; t, t,
tracheidal mantle; pc, pollen-chamber; a, archegonia; td,
tracheidal pad. B–D, Conostoma oblongum; a, level of the
transverse section shown in fig. C; b, level of transverse section D;
m, lobes of tissue surrounding the micropyle; sa, sarcotesta; v,
vascular bundles; p, plinth. B′, section of lagenostome and part of
and nucellus; n, nucellus; e, inner part of testa; sc, sclerotesta; t, t,
tracheidal mantle; pc, pollen-chamber; a, archegonia; td,
tracheidal pad. B–D, Conostoma oblongum; a, level of the
transverse section shown in fig. C; b, level of transverse section D;
m, lobes of tissue surrounding the micropyle; sa, sarcotesta; v,
vascular bundles; p, plinth. B′, section of lagenostome and part of
Page 356
the integument; f, f′, flanges; l′, wall of micropyle-funnel. E, F, G,
Gnetopsis elliptica; t, tent-pole. F, section of the plumes. G, section
through the lagenostome. H, Gnetopsis from Barnsley, Yorkshire,
slightly enlarged. I, Physostoma elegans; h, hairs. K, L,
Mitrospermum compressum; cf, inner flesh; n, nucellus and
megaspore. L, transverse section. M, microspores and (?) male
gametes of Physostoma elegans. N, microspore of Physostoma
showing part of exine and the internal cells. (A–I, N, M, after
Oliver; H, Kidston Coll. No. 1255; K, L, after Mrs Arber.)
The species Conostoma anglo-germanicum agrees closely with C.
oblongum in general form and organisation, but it has eight ribs, four more
prominent than the others, and differs also in other minor characters from
the rather shorter seeds of the type-species. Conostoma differs from
Lagenostoma in the absence of the tubular prolongation of the lagenostome,
the micropyle being like that in recent Gymnosperms. In Conostoma the
tracheid-like elements of the lateral wall of the lagenostome are a
characteristic feature, and no evidence has been found of the existence of a
central core of tissue such as occupies the centre of the seed-apex in
Lagenostoma. The long hairs of Physostoma are represented in Conostoma
by the much smaller mucilaginous cells of the epidermis and in
Lagenostoma by the less closely united mucilage-cells of the superficial
layer of the testa.
Sphaerostoma. Benson.
As already pointed out in Chapter xxix. where this genus is described as
probably the seed of Heterangium, there is a fairly close general
resemblance between Sphaerostoma and Lagenostoma. In the presence of
free apical lobes the former genus resembles Conostoma, and while
agreeing with Lagenostoma in its annular pollen-chamber it is peculiar in
the retention of an epidermis over the roof of the pollen-chamber: as in
Lagenostoma the seed is enclosed by an outer integument or cupule.
Lagenostoma. Williamson.
Gnetopsis elliptica; t, tent-pole. F, section of the plumes. G, section
through the lagenostome. H, Gnetopsis from Barnsley, Yorkshire,
slightly enlarged. I, Physostoma elegans; h, hairs. K, L,
Mitrospermum compressum; cf, inner flesh; n, nucellus and
megaspore. L, transverse section. M, microspores and (?) male
gametes of Physostoma elegans. N, microspore of Physostoma
showing part of exine and the internal cells. (A–I, N, M, after
Oliver; H, Kidston Coll. No. 1255; K, L, after Mrs Arber.)
The species Conostoma anglo-germanicum agrees closely with C.
oblongum in general form and organisation, but it has eight ribs, four more
prominent than the others, and differs also in other minor characters from
the rather shorter seeds of the type-species. Conostoma differs from
Lagenostoma in the absence of the tubular prolongation of the lagenostome,
the micropyle being like that in recent Gymnosperms. In Conostoma the
tracheid-like elements of the lateral wall of the lagenostome are a
characteristic feature, and no evidence has been found of the existence of a
central core of tissue such as occupies the centre of the seed-apex in
Lagenostoma. The long hairs of Physostoma are represented in Conostoma
by the much smaller mucilaginous cells of the epidermis and in
Lagenostoma by the less closely united mucilage-cells of the superficial
layer of the testa.
Sphaerostoma. Benson.
As already pointed out in Chapter xxix. where this genus is described as
probably the seed of Heterangium, there is a fairly close general
resemblance between Sphaerostoma and Lagenostoma. In the presence of
free apical lobes the former genus resembles Conostoma, and while
agreeing with Lagenostoma in its annular pollen-chamber it is peculiar in
the retention of an epidermis over the roof of the pollen-chamber: as in
Lagenostoma the seed is enclosed by an outer integument or cupule.
Lagenostoma. Williamson.
Page 357
An account of this type of seed is included in the description of
Lyginopteris[837]. The more striking peculiarities are exhibited by the pollen-
chamber and the free region of the integument: the annular pollen-chamber
(fig. 493, D, c; fig. 409) surrounds a central nucellar cone and is prolonged
upwards as a tube engaging with the micropyle in contrast to the form of
the pollen-chamber and the absence of a tubular prolongation in
Conostoma. The tentacles of Physostoma and the short apical lobes of
Conostoma are replaced by an apical cone formed by the coalescence of the
integument containing nine cavities originally filled with parenchyma (figs.
409; 493, B). The presence of a cupule is a characteristic feature of young
seeds, but from negative evidence in the case of most other seeds it is
unsafe to assume that the cupule of Lagenostoma is an exceptional feature.
The nucellus and testa are united as far as the shoulders of the seed as in the
seeds of recent Cycads and in contrast to their lateral independence in
Trigonocarpus, Stephanospermum, and other genera.
Gnetopsis. Renault.
This generic name was given by Renault[838] to some small petrified seeds
from the Stephanian of Grand’ Croix and to impressions from the
Commentry coal-field which he believed to belong to some Gnetaceous
plant. Saporta and Marion[839] and other authors have accepted these seeds
as evidence of the existence of Palaeozoic Gnetales: it has, however, been
shown[840] that Gnetopsis has no claim to such relationship and is a type of
seed closely allied to Conostoma. Renault described three species,
afterwards adding three from another locality[841]; the genus is recorded also
from Commentry[842] and Gard[843]. More recently Depape and Carpentier[844]
have described examples from the Westphalian of Valenciennes which they
place in the Pteridosperms in accordance with the conclusion of Oliver and
Salisbury. Gnetopsis has also been discovered by Mr Hemingway in the
Middle Coal Measures of England[845] (fig. 494, H).
Gnetopsis elliptica Renault.
The seeds of this species, slightly oval in section, occur in groups of 2–4
in a cupular investment (fig. 506, E, p. 359) described by Renault as an
ovary but correlated by Oliver and Salisbury with the cupule which
surrounds the single ovule of Lagenostoma. The cupule is lined with hairs
Lyginopteris[837]. The more striking peculiarities are exhibited by the pollen-
chamber and the free region of the integument: the annular pollen-chamber
(fig. 493, D, c; fig. 409) surrounds a central nucellar cone and is prolonged
upwards as a tube engaging with the micropyle in contrast to the form of
the pollen-chamber and the absence of a tubular prolongation in
Conostoma. The tentacles of Physostoma and the short apical lobes of
Conostoma are replaced by an apical cone formed by the coalescence of the
integument containing nine cavities originally filled with parenchyma (figs.
409; 493, B). The presence of a cupule is a characteristic feature of young
seeds, but from negative evidence in the case of most other seeds it is
unsafe to assume that the cupule of Lagenostoma is an exceptional feature.
The nucellus and testa are united as far as the shoulders of the seed as in the
seeds of recent Cycads and in contrast to their lateral independence in
Trigonocarpus, Stephanospermum, and other genera.
Gnetopsis. Renault.
This generic name was given by Renault[838] to some small petrified seeds
from the Stephanian of Grand’ Croix and to impressions from the
Commentry coal-field which he believed to belong to some Gnetaceous
plant. Saporta and Marion[839] and other authors have accepted these seeds
as evidence of the existence of Palaeozoic Gnetales: it has, however, been
shown[840] that Gnetopsis has no claim to such relationship and is a type of
seed closely allied to Conostoma. Renault described three species,
afterwards adding three from another locality[841]; the genus is recorded also
from Commentry[842] and Gard[843]. More recently Depape and Carpentier[844]
have described examples from the Westphalian of Valenciennes which they
place in the Pteridosperms in accordance with the conclusion of Oliver and
Salisbury. Gnetopsis has also been discovered by Mr Hemingway in the
Middle Coal Measures of England[845] (fig. 494, H).
Gnetopsis elliptica Renault.
The seeds of this species, slightly oval in section, occur in groups of 2–4
in a cupular investment (fig. 506, E, p. 359) described by Renault as an
ovary but correlated by Oliver and Salisbury with the cupule which
surrounds the single ovule of Lagenostoma. The cupule is lined with hairs
Page 358
similar to those on the wall of the cupule of Lagenostoma. A characteristic
feature of the French seeds is the presence of three or four long plumes of
hairs at the apex (fig. 494, E, F). As seen in fig. 494, E, a small lagenostome
(pollen-chamber) rests on the roof of a broad plinth precisely as in
Conostoma, and four vascular bundles, corresponding to the six bundles in
Conostoma, pass into the apical cap of sclerous tissue enclosed by a
sarcotesta, sa (fig. 494, E, G). A ‘tent-pole’ prolongation (fig. 494, E, t)
occurs at the apex of the prothallus. Renault described a portion of the
integument as consisting of lacunar tissue which Oliver and Salisbury
homologise with the superficial mucilaginous layer of Conostoma: this is
seen above the sclerotesta in the apical region of fig. 494, E, sa.
Gnetopsis anglica Kidston ms.
This species (fig. 494, H) is represented by seeds from the Middle Coal
Measures near Barnsley, Yorkshire, 4 mm. long with apical appendages at
least 2·2 cm. in length and probably four in number. The appendages do not
show the hairs which form a prominent feature in the French specimens, but
this is probably the result of imperfect preservation: there are indications of
hairs on other specimens in Dr Kidston’s Collection. The type-specimen, in
Dr Kidston’s Collection, was generously lent to me for examination.
Gnetopsis, while agreeing with Conostoma in the more important
features, is distinguished by the apical plumes, the very slight development
of a tent-pole prolongation of the nucellar apex (fig. 494, E, t), the smaller
number of vascular bundles, and by the presence of an enclosing cupule
(fig. 506, E). In its slight departure from radial symmetry Gnetopsis forms a
transition between the Radiospermeae and the Platyspermeae. It is
undoubtedly the seed of a Pteridosperm, but nothing is known as to the
nature of the vegetative organs of the parent-plant.
II. Trigonocarpales.
In this group are included radially symmetrical seeds for the most part
belonging to members of the Medulloseae. The peripheral zone of the
nucellus is supplied with vascular tissue and the nucellus is free within the
integument except at the base; it is superior and not semi-inferior[846] as in
recent Cycads and in Lagenostomales. The ovule of Myrica Gale, in which
the nucellus stands free within the single integument, affords an interesting
feature of the French seeds is the presence of three or four long plumes of
hairs at the apex (fig. 494, E, F). As seen in fig. 494, E, a small lagenostome
(pollen-chamber) rests on the roof of a broad plinth precisely as in
Conostoma, and four vascular bundles, corresponding to the six bundles in
Conostoma, pass into the apical cap of sclerous tissue enclosed by a
sarcotesta, sa (fig. 494, E, G). A ‘tent-pole’ prolongation (fig. 494, E, t)
occurs at the apex of the prothallus. Renault described a portion of the
integument as consisting of lacunar tissue which Oliver and Salisbury
homologise with the superficial mucilaginous layer of Conostoma: this is
seen above the sclerotesta in the apical region of fig. 494, E, sa.
Gnetopsis anglica Kidston ms.
This species (fig. 494, H) is represented by seeds from the Middle Coal
Measures near Barnsley, Yorkshire, 4 mm. long with apical appendages at
least 2·2 cm. in length and probably four in number. The appendages do not
show the hairs which form a prominent feature in the French specimens, but
this is probably the result of imperfect preservation: there are indications of
hairs on other specimens in Dr Kidston’s Collection. The type-specimen, in
Dr Kidston’s Collection, was generously lent to me for examination.
Gnetopsis, while agreeing with Conostoma in the more important
features, is distinguished by the apical plumes, the very slight development
of a tent-pole prolongation of the nucellar apex (fig. 494, E, t), the smaller
number of vascular bundles, and by the presence of an enclosing cupule
(fig. 506, E). In its slight departure from radial symmetry Gnetopsis forms a
transition between the Radiospermeae and the Platyspermeae. It is
undoubtedly the seed of a Pteridosperm, but nothing is known as to the
nature of the vegetative organs of the parent-plant.
II. Trigonocarpales.
In this group are included radially symmetrical seeds for the most part
belonging to members of the Medulloseae. The peripheral zone of the
nucellus is supplied with vascular tissue and the nucellus is free within the
integument except at the base; it is superior and not semi-inferior[846] as in
recent Cycads and in Lagenostomales. The ovule of Myrica Gale, in which
the nucellus stands free within the single integument, affords an interesting
Page 359
parallel to seeds of this class in contrast to the usual Angiospermous type
with a laterally coalescent nucellus. In Myrica Gale[847] the vascular supply
is confined to the integument. There is a comparatively broad pollen-
chamber and in some types the lateral tissue of the nucellus is prolonged as
a tube within the micropyle. The usually ribbed testa is differentiated into
an outer flesh (sarcotesta), a sclerotesta, and probably in most cases an
endotesta or inner flesh. The ribs of the sclerotesta are in the majority of
genera in multiples of three and in position correspond to the outer ring of
vascular bundles. The presence of lacunar tissue in the sarcotesta of several
genera may be correlated with dispersal by water. The apical region of the
integument is not lobed but extends as a longer or shorter micropylar tube
above the summit of the nucellus. In the differentiation of the testa, the
form of the pollen-chamber, and in some other features, the seeds of this
group present a general agreement with those of recent Cycads.
The microspores are multicellular and larger than those of the
Lagenostomales: in Stephanospermum akenioides they measure 160μ ×
100μ[848] while in Aetheotesta[849] they reach 360μ × 290μ.
Genera. Trigonocarpus; Tripterospermum; Ptychotesta;
Hexapterospermum; Polypterospermum; Pachytesta; Stephanospermum;
Polylophospermum; Codonospermum; Aetheotesta; Eriotesta; Gaudrya.
Trigonocarpus. Brongniart.
A description of the morphological features of Trigonocarpus Parkinsoni
and T. shorensis is given in the chapter on Medullosa (p. 117), as there is
good evidence that they are the seeds of that genus. There is considerable
difference in size and to some extent in the form of casts included in
Trigonocarpus and, in the absence of anatomical data, it is hardly possible
to determine the actual systematic position of many of the specimens so
named. Dr Arber[850] has recently proposed a new generic name
Schizospermum for casts very like those of T. Parkinsoni, but distinguished
by the splitting of the shell into three valves, a character which leads him to
conclude that it is the external surface which is preserved and not a mere
cast of the seed-cavity. It is, however, more probable that the specimens are
casts of a split sclerotesta. In Trigonocarpus pusillus[851] the shell is divided
into three valves, the dividing lines being marked by greatly reduced ribs,
with a laterally coalescent nucellus. In Myrica Gale[847] the vascular supply
is confined to the integument. There is a comparatively broad pollen-
chamber and in some types the lateral tissue of the nucellus is prolonged as
a tube within the micropyle. The usually ribbed testa is differentiated into
an outer flesh (sarcotesta), a sclerotesta, and probably in most cases an
endotesta or inner flesh. The ribs of the sclerotesta are in the majority of
genera in multiples of three and in position correspond to the outer ring of
vascular bundles. The presence of lacunar tissue in the sarcotesta of several
genera may be correlated with dispersal by water. The apical region of the
integument is not lobed but extends as a longer or shorter micropylar tube
above the summit of the nucellus. In the differentiation of the testa, the
form of the pollen-chamber, and in some other features, the seeds of this
group present a general agreement with those of recent Cycads.
The microspores are multicellular and larger than those of the
Lagenostomales: in Stephanospermum akenioides they measure 160μ ×
100μ[848] while in Aetheotesta[849] they reach 360μ × 290μ.
Genera. Trigonocarpus; Tripterospermum; Ptychotesta;
Hexapterospermum; Polypterospermum; Pachytesta; Stephanospermum;
Polylophospermum; Codonospermum; Aetheotesta; Eriotesta; Gaudrya.
Trigonocarpus. Brongniart.
A description of the morphological features of Trigonocarpus Parkinsoni
and T. shorensis is given in the chapter on Medullosa (p. 117), as there is
good evidence that they are the seeds of that genus. There is considerable
difference in size and to some extent in the form of casts included in
Trigonocarpus and, in the absence of anatomical data, it is hardly possible
to determine the actual systematic position of many of the specimens so
named. Dr Arber[850] has recently proposed a new generic name
Schizospermum for casts very like those of T. Parkinsoni, but distinguished
by the splitting of the shell into three valves, a character which leads him to
conclude that it is the external surface which is preserved and not a mere
cast of the seed-cavity. It is, however, more probable that the specimens are
casts of a split sclerotesta. In Trigonocarpus pusillus[851] the shell is divided
into three valves, the dividing lines being marked by greatly reduced ribs,
Page 360
and in T. schizocarpoides Grand’Eury[852], a species that may not be a true
Trigonocarpus, there is also evidence of splitting. Arber points out that the
species Rhabdocarpus Boschianus Berg. is founded on a Trigonocarpus
from which the outer flesh has disappeared leaving the shell as the external
covering. Trigonocarpus seeds are widely distributed in Carboniferous and
Permian rocks in Europe and North America: from the latter continent
Newberry[853] has described several different forms that afford good
examples of the abundance and variety of the genus. Some of the specimens
included by Newberry[854] in Trigonocarpus are probably distinct generic
types: his species T. multicarinatus may be identical with the ribbed cast
shown in fig. 506, A. The casts described by Lindley and Hutton and by
other authors as T. Dawesi[855] are nearly 5 cm. long, and if these are
correctly included in the genus they point to the occurrence of seeds much
larger than the type-species. The French species Trigonocarpus pusillus[856]
Brongn., one of the smallest Palaeozoic seeds, from 6·5 to 15 mm. long,
differs from Trigonocarpus Parkinsoni and T. shorensis in the absence of
prominent ribs and in the much feebler development of the sarcotesta.
Specimens of the German type T. sporites Weiss, believed by some authors
to be megaspores, were described by Zeiller[857] from Valenciennes as seeds:
these are from 2·5 to 3·5 mm. long and have three small ribs. Zeiller quotes
the presence of cell-outlines on the surface as evidence of their seed-nature,
but it may be that this feature represents a sculpturing of the exine of a
spore. Typical Trigonocarpus seeds agree in several morphological
characters with those of recent Cycads. They differ in the lack of a lateral
union between nucellus and integument; the presence of nucellar tracheids,
though a feature shared with Bowenia, distinguishes them from the majority
of recent Cycadean seeds. In the comparatively long and fleshy micropylar
tube a seed of Encephalartos Lehmanni presents a fairly close resemblance
to a Trigonocarpus. Salisbury has pointed out that the three species T.
Parkinsoni, T. shorensis, T. pusillus form a consecutive series illustrating
the gradual disappearance of the secondary ribs that form a prominent
feature in T. Parkinsoni; but for a comparison of these with other types of
fossil and recent seeds the reader is referred to Salisbury’s summary[858].
Tripterospermum. Brongniart.
Trigonocarpus, there is also evidence of splitting. Arber points out that the
species Rhabdocarpus Boschianus Berg. is founded on a Trigonocarpus
from which the outer flesh has disappeared leaving the shell as the external
covering. Trigonocarpus seeds are widely distributed in Carboniferous and
Permian rocks in Europe and North America: from the latter continent
Newberry[853] has described several different forms that afford good
examples of the abundance and variety of the genus. Some of the specimens
included by Newberry[854] in Trigonocarpus are probably distinct generic
types: his species T. multicarinatus may be identical with the ribbed cast
shown in fig. 506, A. The casts described by Lindley and Hutton and by
other authors as T. Dawesi[855] are nearly 5 cm. long, and if these are
correctly included in the genus they point to the occurrence of seeds much
larger than the type-species. The French species Trigonocarpus pusillus[856]
Brongn., one of the smallest Palaeozoic seeds, from 6·5 to 15 mm. long,
differs from Trigonocarpus Parkinsoni and T. shorensis in the absence of
prominent ribs and in the much feebler development of the sarcotesta.
Specimens of the German type T. sporites Weiss, believed by some authors
to be megaspores, were described by Zeiller[857] from Valenciennes as seeds:
these are from 2·5 to 3·5 mm. long and have three small ribs. Zeiller quotes
the presence of cell-outlines on the surface as evidence of their seed-nature,
but it may be that this feature represents a sculpturing of the exine of a
spore. Typical Trigonocarpus seeds agree in several morphological
characters with those of recent Cycads. They differ in the lack of a lateral
union between nucellus and integument; the presence of nucellar tracheids,
though a feature shared with Bowenia, distinguishes them from the majority
of recent Cycadean seeds. In the comparatively long and fleshy micropylar
tube a seed of Encephalartos Lehmanni presents a fairly close resemblance
to a Trigonocarpus. Salisbury has pointed out that the three species T.
Parkinsoni, T. shorensis, T. pusillus form a consecutive series illustrating
the gradual disappearance of the secondary ribs that form a prominent
feature in T. Parkinsoni; but for a comparison of these with other types of
fossil and recent seeds the reader is referred to Salisbury’s summary[858].
Tripterospermum. Brongniart.
Page 361
The seed on which this genus was founded by Brongniart[859] is clearly
very closely related to Trigonocarpus and, as Oliver[860] says, the
distinguishing character described by the author of the genus is
unimportant. Brongniart describes the type species, T. rostratum, as
characterised by the presence of three prominent wings composed of a testa
differentiated into an inner hard tissue and an outer lacunar tissue. It is,
however, hardly possible to say whether the outer soft tissue was originally
flattened in the form of ‘wings’ or pressed down on to the harder shell.
Renault[861] notes the association of seeds that he refers to this genus with
the leaves of Dorycordaites, but apart from the improbability of any
connexion between Tripterospermum and Cordaites, Renault’s seeds are too
imperfect to demonstrate their identity with Brongniart’s genus. Kidston[862]
has described an impression of a three-winged seed from the coal-field of
Staffordshire as Tripterospermum ellipticum, a form described on page 357
as Polypterocarpus anglicus (fig. 496, B).
Ptychotesta. Brongniart.
The type-species of this genus[863], Ptychotesta tenuis[864], about 3 cm.
long, is characterised by six very prominent flanges or wings formed by the
fissured or folded sclerotesta (fig. 495, B). There is no information as to the
vascular supply or other anatomical details. It is not at all improbable that
there is no real distinction between this genus and Brongniart’s genus
Hexapterospermum.
Hexapterospermum. Brongniart.
In this genus Brongniart[865] included two species, Hexapterospermum
stenopterum and H. pachypterum: the shell is hexagonal in transverse
section, each angle being prolonged as a narrow flange. In one of the
sections figured by Brongniart (fig. 495, E) the ribs are not fissured: this is
said to be a feature distinguishing Hexapterospermum from Ptychotesta, but
the occurrence of a fissured rib in another section suggests that in the
structure of the ribs there is no essential difference between the two genera.
In Ptychotesta pachypterum the testa is prolonged at the chalazal end as in
Polylophospermum, and it is possible that there is no generic difference.
Williamson described a cast from the Coal Measures of Lancashire as
very closely related to Trigonocarpus and, as Oliver[860] says, the
distinguishing character described by the author of the genus is
unimportant. Brongniart describes the type species, T. rostratum, as
characterised by the presence of three prominent wings composed of a testa
differentiated into an inner hard tissue and an outer lacunar tissue. It is,
however, hardly possible to say whether the outer soft tissue was originally
flattened in the form of ‘wings’ or pressed down on to the harder shell.
Renault[861] notes the association of seeds that he refers to this genus with
the leaves of Dorycordaites, but apart from the improbability of any
connexion between Tripterospermum and Cordaites, Renault’s seeds are too
imperfect to demonstrate their identity with Brongniart’s genus. Kidston[862]
has described an impression of a three-winged seed from the coal-field of
Staffordshire as Tripterospermum ellipticum, a form described on page 357
as Polypterocarpus anglicus (fig. 496, B).
Ptychotesta. Brongniart.
The type-species of this genus[863], Ptychotesta tenuis[864], about 3 cm.
long, is characterised by six very prominent flanges or wings formed by the
fissured or folded sclerotesta (fig. 495, B). There is no information as to the
vascular supply or other anatomical details. It is not at all improbable that
there is no real distinction between this genus and Brongniart’s genus
Hexapterospermum.
Hexapterospermum. Brongniart.
In this genus Brongniart[865] included two species, Hexapterospermum
stenopterum and H. pachypterum: the shell is hexagonal in transverse
section, each angle being prolonged as a narrow flange. In one of the
sections figured by Brongniart (fig. 495, E) the ribs are not fissured: this is
said to be a feature distinguishing Hexapterospermum from Ptychotesta, but
the occurrence of a fissured rib in another section suggests that in the
structure of the ribs there is no essential difference between the two genera.
In Ptychotesta pachypterum the testa is prolonged at the chalazal end as in
Polylophospermum, and it is possible that there is no generic difference.
Williamson described a cast from the Coal Measures of Lancashire as
Page 362
Hexapterospermum [= Hexagonocarpus] Noegerrathi[866] (fig. 506, H), but
in the absence of anatomical characters it is preferable to avoid the use of
Brongniart’s term and to assign them to Renault’s genus
Hexagonocarpus[867]. Similarly the seeds referred by Dr P. Bertrand[868] to
Hexapterospermum may appropriately be included in the genus
Hexagonocarpus.
Fig. 495. A, Polypterospermum Renaultii. B, Ptychotesta tenuis. C, D,
Polylophospermum stephanense; sa, sarcotesta; s, spaces; v,
vascular bundles. E, Hexapterospermum stenopterum. F, Diplotesta
avellana. G, Taxospermum Grüneri. H, Diplotesta Grand’Euryana.
(After Brongniart; C, after Oliver.)
in the absence of anatomical characters it is preferable to avoid the use of
Brongniart’s term and to assign them to Renault’s genus
Hexagonocarpus[867]. Similarly the seeds referred by Dr P. Bertrand[868] to
Hexapterospermum may appropriately be included in the genus
Hexagonocarpus.
Fig. 495. A, Polypterospermum Renaultii. B, Ptychotesta tenuis. C, D,
Polylophospermum stephanense; sa, sarcotesta; s, spaces; v,
vascular bundles. E, Hexapterospermum stenopterum. F, Diplotesta
avellana. G, Taxospermum Grüneri. H, Diplotesta Grand’Euryana.
(After Brongniart; C, after Oliver.)
Page 363
Polypterospermum. Brongniart.
This generic name was proposed for an ovoid seed from St Étienne
described as Polypterospermum Renaultii[869]; hexagonal in section with six
deep and sharp flanges at the angles alternating with six secondary ridges
distinguished by their blunter edges and slightly smaller depth (fig. 495, A).
Without further anatomical details it is hardly possible to say whether or not
the species represents a well-defined generic type, but it is not improbable
that a fuller knowledge would confirm Brongniart’s institution of a new
generic designation. The seeds described by Arber[870] and Kidston[871]
respectively as Radiospermum ornatum and Polypterospermum ornatum are
transferred to Polygonocarpus on the ground that they afford no evidence of
anatomical characters of the Polypterospermum type.
Pachytesta. Brongniart.
Brongniart[872] established this genus for some unusually large seeds (fig.
496, A) from the Coal Measures of France reaching a length of 11–12 cm.
and resembling in form and size a hen’s egg. Petrified examples have been
described by Brongniart and Renault[873], and Oliver[874] has given a lucid
statement of the more interesting features of this Permo-Carboniferous
genus.
Pachytesta gigantea (Grand’Eury).
In the separation of nucellus and integument Pachytesta agrees with
Stephanospermum and Trigonocarpus. There is a double series of vascular
bundles in the outer part of the testa or exotesta (fig. 497, ex) consisting of a
spongy tissue bounded externally and internally by sclerotic layers: the
exotesta is succeeded by a broader endotesta of spongy consistency which
Renault suggested may have served as a floating mechanism, and this is
intimately associated with the nucellus by means of grooves engaging with
short ridges (fig. 497, nr) on the surface of the nucellar tissue. The exotesta
is divided into three valves by radial extensions of the sclerotic tissue (b, c,
fig. 497; at a the exotesta is shown in an unsplit condition). In connexion
with each radial plate are two curved plates of fibrous tissue which extend
towards the grooves in the endotesta (fig. 497, t): as Oliver suggests, these
plates may have served a mechanical purpose for the support of the bulky
This generic name was proposed for an ovoid seed from St Étienne
described as Polypterospermum Renaultii[869]; hexagonal in section with six
deep and sharp flanges at the angles alternating with six secondary ridges
distinguished by their blunter edges and slightly smaller depth (fig. 495, A).
Without further anatomical details it is hardly possible to say whether or not
the species represents a well-defined generic type, but it is not improbable
that a fuller knowledge would confirm Brongniart’s institution of a new
generic designation. The seeds described by Arber[870] and Kidston[871]
respectively as Radiospermum ornatum and Polypterospermum ornatum are
transferred to Polygonocarpus on the ground that they afford no evidence of
anatomical characters of the Polypterospermum type.
Pachytesta. Brongniart.
Brongniart[872] established this genus for some unusually large seeds (fig.
496, A) from the Coal Measures of France reaching a length of 11–12 cm.
and resembling in form and size a hen’s egg. Petrified examples have been
described by Brongniart and Renault[873], and Oliver[874] has given a lucid
statement of the more interesting features of this Permo-Carboniferous
genus.
Pachytesta gigantea (Grand’Eury).
In the separation of nucellus and integument Pachytesta agrees with
Stephanospermum and Trigonocarpus. There is a double series of vascular
bundles in the outer part of the testa or exotesta (fig. 497, ex) consisting of a
spongy tissue bounded externally and internally by sclerotic layers: the
exotesta is succeeded by a broader endotesta of spongy consistency which
Renault suggested may have served as a floating mechanism, and this is
intimately associated with the nucellus by means of grooves engaging with
short ridges (fig. 497, nr) on the surface of the nucellar tissue. The exotesta
is divided into three valves by radial extensions of the sclerotic tissue (b, c,
fig. 497; at a the exotesta is shown in an unsplit condition). In connexion
with each radial plate are two curved plates of fibrous tissue which extend
towards the grooves in the endotesta (fig. 497, t): as Oliver suggests, these
plates may have served a mechanical purpose for the support of the bulky
Page 364
nucellus. The peripheral region of the nucellus is supplied by several
vascular bundles (fig. 497, n) from the tracheal chalazal disc. The exotesta
is regarded by Oliver as corresponding to the sarcotesta and sclerotesta of
other seeds, and the grooves in the endotesta interlocking with the nucellar
ridges are compared with the interlocking of nucellus and canopy in
Lagenostoma, as also with the ruminated endosperm of Torreya.
Fig. 496. A, Pachytesta incrassata. B, Polypterocarpus anglicus. (A, after
Renault; B, after Kidston.)
vascular bundles (fig. 497, n) from the tracheal chalazal disc. The exotesta
is regarded by Oliver as corresponding to the sarcotesta and sclerotesta of
other seeds, and the grooves in the endotesta interlocking with the nucellar
ridges are compared with the interlocking of nucellus and canopy in
Lagenostoma, as also with the ruminated endosperm of Torreya.
Fig. 496. A, Pachytesta incrassata. B, Polypterocarpus anglicus. (A, after
Renault; B, after Kidston.)
Page 365
Fig. 497. Pachytesta. Transverse section of a seed showing the exotesta,
ex, with sclerous layers and vascular strands (black), the endotesta
(dotted), the nucellus with its ring of vascular bundles, n, and the
prothallus, p. The three radial plates in the exotesta are seen at a,
b, c, with the trabeculae, t, and internal to these are the grooves in
the endotesta engaging with ribs on the nucellus, nr. (After Oliver.)
We have no definite information as to the plants which bore Pachytesta,
but it is probable that they were members of the Medulloseae.
Grand’Eury[875] believes Pachytesta to be the seed of Alethopteris Grandini,
though this view requires confirmation. This author figures several
Pachytesta seeds attached in two oblique rows to a comparatively slender
axis which may be the rachis of a large compound frond[876]. Renault and
Zeiller[877] have figured specimens of P. gigantea and P. incrassata from
Commentry which afford a good idea of the form of these large seeds; the
genus is recorded also from Gard, Blanzy[878], and other localities.
Kidston[879] described a large oval seed, blunt at each end, from the Middle
Coal Measures of Lancashire as Carpolithus Wildii which he thinks may be
allied to Pachytesta, but adds, ‘I do not think we are justified in placing
mere impressions of plants in genera, whose distinctive characters are
derived from their internal organisation, unless there is conclusive evidence
ex, with sclerous layers and vascular strands (black), the endotesta
(dotted), the nucellus with its ring of vascular bundles, n, and the
prothallus, p. The three radial plates in the exotesta are seen at a,
b, c, with the trabeculae, t, and internal to these are the grooves in
the endotesta engaging with ribs on the nucellus, nr. (After Oliver.)
We have no definite information as to the plants which bore Pachytesta,
but it is probable that they were members of the Medulloseae.
Grand’Eury[875] believes Pachytesta to be the seed of Alethopteris Grandini,
though this view requires confirmation. This author figures several
Pachytesta seeds attached in two oblique rows to a comparatively slender
axis which may be the rachis of a large compound frond[876]. Renault and
Zeiller[877] have figured specimens of P. gigantea and P. incrassata from
Commentry which afford a good idea of the form of these large seeds; the
genus is recorded also from Gard, Blanzy[878], and other localities.
Kidston[879] described a large oval seed, blunt at each end, from the Middle
Coal Measures of Lancashire as Carpolithus Wildii which he thinks may be
allied to Pachytesta, but adds, ‘I do not think we are justified in placing
mere impressions of plants in genera, whose distinctive characters are
derived from their internal organisation, unless there is conclusive evidence
Page 366
to show their identity.’ On this specimen Arber[880] has founded a new genus
Megalospermum, but as the type-specimen shows no distinctive features
other than large dimensions it would seem preferable to retain the more
general designation Carpolithus[881].
Another example of a seed that may be generically identical with
Pachytesta is that described by Lesquereux from North American Coal
Measures as Rhabdocarpus Mansfieldi and more recently recorded by
White from Missouri as Rhabdocarpus (Pachytesta) Mansfieldi[882]. There is
little doubt that this and other species of seeds preserved as impressions are
examples of Pachytesta but, as Kidston says, it is preferable to reserve the
name for specimens showing anatomical features.
Stephanospermum. Brongniart.
The genus Stephanospermum, founded by Brongniart[883] on petrified
specimens from French Stephanian beds, affords a good example of a
radiospermic seed without ribs differing in certain well-marked characters
from such seeds as Lagenostoma, Physostoma, and Conostoma, notably in
the complete separation of the nucellus from the integument and in the
possession of a nucellar vascular system. The descriptions by Brongniart
and Renault[884] have been extended by the thorough investigations of
Oliver[885].
Stephanospermum akenioides Brongniart.
This species is represented by ellipsoidal seeds, 10 mm. long with a
maximum breadth of 4–4·5 mm., circular in transverse section. The
integument consists of a thick sclerotesta lined internally by a thinner soft
layer, the endotesta (fig. 494, A, sc, e), and in all probability covered by an
outer flesh or sarcotesta as in Trigonocarpus, though this tissue is not
preserved and is omitted from the section shown in fig. 494, A. The
sclerotesta is composed of a broad outer band of thick-walled palisade cells
—the contracted contents of which are a striking feature in the silicified
seeds (fig. 493, F); these are succeeded by an inner zone of longitudinal
fibres. In the structure of the palisade-layer Stephanospermum bears a close
resemblance to the sporocarp wall of Pilularia[886]. In the apical region the
shell forms a circular ridge surrounding a peri-micropylar trough, a
Megalospermum, but as the type-specimen shows no distinctive features
other than large dimensions it would seem preferable to retain the more
general designation Carpolithus[881].
Another example of a seed that may be generically identical with
Pachytesta is that described by Lesquereux from North American Coal
Measures as Rhabdocarpus Mansfieldi and more recently recorded by
White from Missouri as Rhabdocarpus (Pachytesta) Mansfieldi[882]. There is
little doubt that this and other species of seeds preserved as impressions are
examples of Pachytesta but, as Kidston says, it is preferable to reserve the
name for specimens showing anatomical features.
Stephanospermum. Brongniart.
The genus Stephanospermum, founded by Brongniart[883] on petrified
specimens from French Stephanian beds, affords a good example of a
radiospermic seed without ribs differing in certain well-marked characters
from such seeds as Lagenostoma, Physostoma, and Conostoma, notably in
the complete separation of the nucellus from the integument and in the
possession of a nucellar vascular system. The descriptions by Brongniart
and Renault[884] have been extended by the thorough investigations of
Oliver[885].
Stephanospermum akenioides Brongniart.
This species is represented by ellipsoidal seeds, 10 mm. long with a
maximum breadth of 4–4·5 mm., circular in transverse section. The
integument consists of a thick sclerotesta lined internally by a thinner soft
layer, the endotesta (fig. 494, A, sc, e), and in all probability covered by an
outer flesh or sarcotesta as in Trigonocarpus, though this tissue is not
preserved and is omitted from the section shown in fig. 494, A. The
sclerotesta is composed of a broad outer band of thick-walled palisade cells
—the contracted contents of which are a striking feature in the silicified
seeds (fig. 493, F); these are succeeded by an inner zone of longitudinal
fibres. In the structure of the palisade-layer Stephanospermum bears a close
resemblance to the sporocarp wall of Pilularia[886]. In the apical region the
shell forms a circular ridge surrounding a peri-micropylar trough, a
Page 367
character expressed by the term ‘crown-seed[887]’ employed by Grand’Eury:
the trough sometimes contains partially destroyed tissue that may be a
remnant of a sarcotesta. A Stephanospermum seed, with its apical core and
surrounding depression with remnants of some partially destroyed tissue,
may be compared with a fruit of Attolia speciosa (Palmae) in which a tuft
of fibrous tissue picked out by decay from the mesocarp surmounts the
conically pointed apex of the harder interior of the fruit-wall. The base of
the sclerotesta is perforated by a vascular strand which expands into a
tracheal disc, td, fig. 494, A, at the base of the megaspore from which a
continuous mantle 2–3 cells broad, of short spiral and scalariform tracheids
(fig. 493, G), spreads over the whole of the nucellus immediately below the
nucellar epidermis as far as the lower part of the sides of the pollen-
chamber: this mantle forms the floor of the large domical pollen-chamber
excavated out of the nucellar cone (fig. 494, A, pc). The fact that in sections
of older seeds the tracheal floor shows signs of splitting and disorganisation
led Oliver to conclude that in the living seed the tracheids underwent a
gradual disintegration prior to fertilisation, thus allowing the passage of the
antherozoids to the egg-cells (fig. 494, A, a). The presence of a continuous
tracheal sheath instead of separate vascular bundles is a special feature in
which Stephanospermum differs from Trigonocarpus and other Palaeozoic
seeds as well as from those of recent Cycads; as Oliver suggests, ‘the
apparent perfection of the vascular mantle in Stephanospermum may have
proved an obstacle to further development[888]’ and was not retained by the
more successful types. In its tracheal sheath Stephanospermum resembles
the seeds of Ginkgo. The nucellar cone is prolonged as a beak into the
micropyle formed by the tubular integument. The megaspore occupies the
central portion of the seed and in the course of its development it
compressed the megasporangium (nucellus) to such an extent that little
more than the epidermis remains: there is a definite megaspore-membrane
surrounding the prothallus-tissue in which there were probably two
archegonia (fig. 494, A, a)[889]. The nucellus stands free within the
integument from which it is separated by a space (s, fig. 494, A).
Microspores are frequently met with in the pollen-chamber in which they
matured after their introduction through the micropyle, probably with the
aid of a drop of mucilage: they are large oval bodies with an average size of
160μ × 100μ, some reaching over 200μ, in length and, as Renault was the
first to point out, within a finely granulate exospore there are several thin-
the trough sometimes contains partially destroyed tissue that may be a
remnant of a sarcotesta. A Stephanospermum seed, with its apical core and
surrounding depression with remnants of some partially destroyed tissue,
may be compared with a fruit of Attolia speciosa (Palmae) in which a tuft
of fibrous tissue picked out by decay from the mesocarp surmounts the
conically pointed apex of the harder interior of the fruit-wall. The base of
the sclerotesta is perforated by a vascular strand which expands into a
tracheal disc, td, fig. 494, A, at the base of the megaspore from which a
continuous mantle 2–3 cells broad, of short spiral and scalariform tracheids
(fig. 493, G), spreads over the whole of the nucellus immediately below the
nucellar epidermis as far as the lower part of the sides of the pollen-
chamber: this mantle forms the floor of the large domical pollen-chamber
excavated out of the nucellar cone (fig. 494, A, pc). The fact that in sections
of older seeds the tracheal floor shows signs of splitting and disorganisation
led Oliver to conclude that in the living seed the tracheids underwent a
gradual disintegration prior to fertilisation, thus allowing the passage of the
antherozoids to the egg-cells (fig. 494, A, a). The presence of a continuous
tracheal sheath instead of separate vascular bundles is a special feature in
which Stephanospermum differs from Trigonocarpus and other Palaeozoic
seeds as well as from those of recent Cycads; as Oliver suggests, ‘the
apparent perfection of the vascular mantle in Stephanospermum may have
proved an obstacle to further development[888]’ and was not retained by the
more successful types. In its tracheal sheath Stephanospermum resembles
the seeds of Ginkgo. The nucellar cone is prolonged as a beak into the
micropyle formed by the tubular integument. The megaspore occupies the
central portion of the seed and in the course of its development it
compressed the megasporangium (nucellus) to such an extent that little
more than the epidermis remains: there is a definite megaspore-membrane
surrounding the prothallus-tissue in which there were probably two
archegonia (fig. 494, A, a)[889]. The nucellus stands free within the
integument from which it is separated by a space (s, fig. 494, A).
Microspores are frequently met with in the pollen-chamber in which they
matured after their introduction through the micropyle, probably with the
aid of a drop of mucilage: they are large oval bodies with an average size of
160μ × 100μ, some reaching over 200μ, in length and, as Renault was the
first to point out, within a finely granulate exospore there are several thin-
Page 368
walled cells: this statement was not accepted by some authors but Prof.
Oliver’s researches have amply confirmed it, and an examination of the
original preparations convinced me that Renault had correctly described the
structural features. Oliver shows that there are about 20 cells within each
microspore regularly arranged as rows of five wedge-shaped elements with
their pointed ends directed towards the centre, and he thinks that these cells
may have undergone further division to produce sperm-mother-cells,
though there is not such good evidence of this as in the differently
constituted microspores of Stephanospermum caryoides. No trace of pollen-
tubes was found and it is probable that the antherozoids were liberated by
the rupture of the delicate prothallus-tissue. The tracheal sheath afforded an
adequate means of water-supply to the pollen-chamber and this enabled the
motile antherozoids to reach the archegonia.
Stephanospermum caryoides Oliver[890].
This species, founded on a specimen from ., is a larger seed (15·5 × 12·5
mm.) and more globular than S. akenioides; there is a shorter micropylar
beak and a less developed peri-micropylar trough. As in S. akenioides the
nucellus is free from the base and the two species conform to the same
general type of construction. The microspores are distinguished by the
presence of only two internal cells which do not occupy the whole of the
spore-cavity but are surrounded by a large peripheral cell comparable with
the tube-cell in recent microspores, though there is no proof that a tube was
formed: in the case of S. akenioides Oliver considers that fertilisation was
not assisted by the production of a pollen-tube. The two cells by further
division gave rise to a secondary cell-complex consisting of at least eight
antherozoid-mother-cells. No antherozoids have been found in the
microspores but it is possible that two small bodies, 17μ × 15μ, met with in
a pollen-chamber may represent the nuclei of sperms. Their small size
differentiates them from the much larger male gametes of Cycads and from
the supposed sperms of Physostoma and Lagenostoma.
We have no proof as to the nature of the plant which bore seeds of the
Stephanospermum type, but it is significant that the specimens occur in
close association with fragments of Alethopteris and Myeloxylon, a
circumstance that favours the view, based on the resemblance of these seeds
Oliver’s researches have amply confirmed it, and an examination of the
original preparations convinced me that Renault had correctly described the
structural features. Oliver shows that there are about 20 cells within each
microspore regularly arranged as rows of five wedge-shaped elements with
their pointed ends directed towards the centre, and he thinks that these cells
may have undergone further division to produce sperm-mother-cells,
though there is not such good evidence of this as in the differently
constituted microspores of Stephanospermum caryoides. No trace of pollen-
tubes was found and it is probable that the antherozoids were liberated by
the rupture of the delicate prothallus-tissue. The tracheal sheath afforded an
adequate means of water-supply to the pollen-chamber and this enabled the
motile antherozoids to reach the archegonia.
Stephanospermum caryoides Oliver[890].
This species, founded on a specimen from ., is a larger seed (15·5 × 12·5
mm.) and more globular than S. akenioides; there is a shorter micropylar
beak and a less developed peri-micropylar trough. As in S. akenioides the
nucellus is free from the base and the two species conform to the same
general type of construction. The microspores are distinguished by the
presence of only two internal cells which do not occupy the whole of the
spore-cavity but are surrounded by a large peripheral cell comparable with
the tube-cell in recent microspores, though there is no proof that a tube was
formed: in the case of S. akenioides Oliver considers that fertilisation was
not assisted by the production of a pollen-tube. The two cells by further
division gave rise to a secondary cell-complex consisting of at least eight
antherozoid-mother-cells. No antherozoids have been found in the
microspores but it is possible that two small bodies, 17μ × 15μ, met with in
a pollen-chamber may represent the nuclei of sperms. Their small size
differentiates them from the much larger male gametes of Cycads and from
the supposed sperms of Physostoma and Lagenostoma.
We have no proof as to the nature of the plant which bore seeds of the
Stephanospermum type, but it is significant that the specimens occur in
close association with fragments of Alethopteris and Myeloxylon, a
circumstance that favours the view, based on the resemblance of these seeds
Page 369
to Trigonocarpus, that Stephanospermum is the seed of a member of the
Medulloseae.
Polylophospermum[891]. Brongniart.
The type-species Polylophospermum stephanense Brongn.[892], founded
on partially preserved material from Grand’ Croix, is a narrow hexagonal
seed 15 mm. long. Additional facts as to the structural features have been
contributed by Oliver[893]. The testa is differentiated into an inner shell
(sclerotesta) and an outer flesh (sa, fig. 495, C, D): the sclerotesta has six
prominent, fissured, ribs, one at each angle, and between these are six solid
and less prominent secondary ribs. Oliver states that there is an outer series
of vascular bundles in the sarcotesta, one bundle immediately external to
each secondary rib (fig. 495, C, v). In the presence of two kinds of ribs and
in the relation of ribs to tracheal strands Polylophospermum agrees with
Trigonocarpus Parkinsoni. Strands of short tracheids supply the peripheral
region of the nucellus and, as in Stephanospermum, reticulate elements
extend as far as the floor of the large pollen-chamber. There was probably
no lateral union between nucellus and integument. A striking feature is the
prolongation of the testa at each end of the seed to form an open chamber
surrounding the micropylar beak and the seed-base (fig. 495, D, s, s): the
apical chamber, though relatively more prominent, is comparable with that
in Stephanospermum, while the basal chamber recalls that in the seed
named by Scott and Maslen Trigonocarpus Oliveri[894] but subsequently
removed by Salisbury[895] from that genus. There is no evidence as to the
parent-plant of Polylophospermum, but it may be assumed to have been a
Pteridosperm, probably one of the Medulloseae.
Medulloseae.
Polylophospermum[891]. Brongniart.
The type-species Polylophospermum stephanense Brongn.[892], founded
on partially preserved material from Grand’ Croix, is a narrow hexagonal
seed 15 mm. long. Additional facts as to the structural features have been
contributed by Oliver[893]. The testa is differentiated into an inner shell
(sclerotesta) and an outer flesh (sa, fig. 495, C, D): the sclerotesta has six
prominent, fissured, ribs, one at each angle, and between these are six solid
and less prominent secondary ribs. Oliver states that there is an outer series
of vascular bundles in the sarcotesta, one bundle immediately external to
each secondary rib (fig. 495, C, v). In the presence of two kinds of ribs and
in the relation of ribs to tracheal strands Polylophospermum agrees with
Trigonocarpus Parkinsoni. Strands of short tracheids supply the peripheral
region of the nucellus and, as in Stephanospermum, reticulate elements
extend as far as the floor of the large pollen-chamber. There was probably
no lateral union between nucellus and integument. A striking feature is the
prolongation of the testa at each end of the seed to form an open chamber
surrounding the micropylar beak and the seed-base (fig. 495, D, s, s): the
apical chamber, though relatively more prominent, is comparable with that
in Stephanospermum, while the basal chamber recalls that in the seed
named by Scott and Maslen Trigonocarpus Oliveri[894] but subsequently
removed by Salisbury[895] from that genus. There is no evidence as to the
parent-plant of Polylophospermum, but it may be assumed to have been a
Pteridosperm, probably one of the Medulloseae.
Page 370
Fig. 498. A, B, Codonospermum. A, C. olivaeforme, longitudinal section
showing the seed-proper and the air-chamber, s; pc, pollen-
chamber. B, Diagrammatic sketch of a Codonospermum showing
the vascular supply, v, and the fibrous arcs, f, in the wall of the
lower part of the seed. C, Aetheotesta elliptica, s, sarcotesta with
lacunae; v, vascular supply. (After Renault.)
Codonospermum[896]. Brongniart.
Our knowledge of this peculiar genus is derived from Brongniart’s
description of the type-species Codonospermum anomalum[897] (fig. 506, B,
C) from St Étienne and from Renault’s account of C. olivaeforme[898]. The
seeds are globular or ellipsoidal and reach a length of 2 cm.: the testa is
differentiated into an outer flesh and a sclerotesta and has usually eight ribs.
The most striking feature is the division of the seed into two regions, an
upper portion containing the nucellus and megaspore and a lower portion in
the form of an empty chamber that probably served as a float (fig. 498, A,
s). Externally the upper half or seed-proper forms a depressed cupola with
eight slightly developed ribs, separated by a circular transverse constriction
from the basal chamber (fig. 498, B). There is a fairly large pollen-chamber,
pc, in which Renault found multicellular microspores in C. olivaeforme. In
C. anomalum 16 vascular bundles (fig. 498, B, v) surround the central
region of the seed probably in the peripheral tissue of the nucellus; these
bundles unite in the chalazal region to form a strand that passes up the
centre of the empty chamber. In C. anomalum the testa of the lower half has
showing the seed-proper and the air-chamber, s; pc, pollen-
chamber. B, Diagrammatic sketch of a Codonospermum showing
the vascular supply, v, and the fibrous arcs, f, in the wall of the
lower part of the seed. C, Aetheotesta elliptica, s, sarcotesta with
lacunae; v, vascular supply. (After Renault.)
Codonospermum[896]. Brongniart.
Our knowledge of this peculiar genus is derived from Brongniart’s
description of the type-species Codonospermum anomalum[897] (fig. 506, B,
C) from St Étienne and from Renault’s account of C. olivaeforme[898]. The
seeds are globular or ellipsoidal and reach a length of 2 cm.: the testa is
differentiated into an outer flesh and a sclerotesta and has usually eight ribs.
The most striking feature is the division of the seed into two regions, an
upper portion containing the nucellus and megaspore and a lower portion in
the form of an empty chamber that probably served as a float (fig. 498, A,
s). Externally the upper half or seed-proper forms a depressed cupola with
eight slightly developed ribs, separated by a circular transverse constriction
from the basal chamber (fig. 498, B). There is a fairly large pollen-chamber,
pc, in which Renault found multicellular microspores in C. olivaeforme. In
C. anomalum 16 vascular bundles (fig. 498, B, v) surround the central
region of the seed probably in the peripheral tissue of the nucellus; these
bundles unite in the chalazal region to form a strand that passes up the
centre of the empty chamber. In C. anomalum the testa of the lower half has
Page 371
eight ribs and corresponding with each rib is a strand of fibrous tissue (fig.
498, B, f). In C. olivaeforme the testa is thicker than in C. anomalum and
the lower region of the seed is smooth and circular in section.
Impressions of Codonospermum are described[899] from Commentry, from
the Loire—the Gard district[900], and by Zeiller[901] from Blanzy. There is no
decisive evidence as to the parent-plant, but some French authors[902] regard
the frequent association of Codonospermum with leaves of Dolerophyllum
as significant.
Aetheotesta. Brongniart.
Aetheotesta elliptica Renault.
Brongniart instituted the genus Aetheotesta[903] for an incomplete seed (A.
subglobosa) from Grand’ Croix, and Renault[904] subsequently founded the
species A. elliptica on much better material. The testa of the elliptical seed,
3 cm. long, consists of an outer region very thin on the flanks but highly
developed at the apex and base which forms a sarcotesta characterised in
the apical region by large radially disposed spaces, fig. 498, C, s; the
sclerotesta, composed of harder tissue, is prolonged as an apical beak. There
is a large pollen-chamber, pc, in which Renault found multicellular
microspores (320μ–400μ). In the chalazal region the main vascular supply
forms a cup-like investment, v, in the basal portion of the nucellus, and at a
higher level this breaks up into several nucellar strands. Renault thinks that
Aetheotesta is the seed of Dolerophyllum, but there is no proof of any
connexion. The presence of large spaces in the sarcotesta may be
interpreted, as Renault suggests, as evidence of adaptation to dispersal by
water.
Eriotesta. Brongniart.
Brongniart[905] instituted this genus[906] on an incomplete transverse
section of a seed from Grand’ Croix, 8 mm. in diameter, which he called
Eriotesta velutina, characterised by a ribbed and probably octagonal testa
bearing numerous elongated hairs over the whole surface. The material is,
however, too meagre to throw any light on the important features of the
seed.
498, B, f). In C. olivaeforme the testa is thicker than in C. anomalum and
the lower region of the seed is smooth and circular in section.
Impressions of Codonospermum are described[899] from Commentry, from
the Loire—the Gard district[900], and by Zeiller[901] from Blanzy. There is no
decisive evidence as to the parent-plant, but some French authors[902] regard
the frequent association of Codonospermum with leaves of Dolerophyllum
as significant.
Aetheotesta. Brongniart.
Aetheotesta elliptica Renault.
Brongniart instituted the genus Aetheotesta[903] for an incomplete seed (A.
subglobosa) from Grand’ Croix, and Renault[904] subsequently founded the
species A. elliptica on much better material. The testa of the elliptical seed,
3 cm. long, consists of an outer region very thin on the flanks but highly
developed at the apex and base which forms a sarcotesta characterised in
the apical region by large radially disposed spaces, fig. 498, C, s; the
sclerotesta, composed of harder tissue, is prolonged as an apical beak. There
is a large pollen-chamber, pc, in which Renault found multicellular
microspores (320μ–400μ). In the chalazal region the main vascular supply
forms a cup-like investment, v, in the basal portion of the nucellus, and at a
higher level this breaks up into several nucellar strands. Renault thinks that
Aetheotesta is the seed of Dolerophyllum, but there is no proof of any
connexion. The presence of large spaces in the sarcotesta may be
interpreted, as Renault suggests, as evidence of adaptation to dispersal by
water.
Eriotesta. Brongniart.
Brongniart[905] instituted this genus[906] on an incomplete transverse
section of a seed from Grand’ Croix, 8 mm. in diameter, which he called
Eriotesta velutina, characterised by a ribbed and probably octagonal testa
bearing numerous elongated hairs over the whole surface. The material is,
however, too meagre to throw any light on the important features of the
seed.
Page 372
Gaudrya. Grand’Eury.
Gaudrya trivalvis Grand’Eury.
The generic name Gaudrya[907] was proposed for two petrified seeds from
the Gard coal-field briefly described as G. trivalvis, the type-species, and G.
lagenaria. The testa of the former species shows signs of splitting along
three equidistant lines; it consists of a sarcotesta enclosing an endotesta
with six longitudinal ribs: Grand’Eury speaks of lacunae between the
endotesta and nucellus which he regards as spaces in a tissue which made
the seed buoyant and facilitated dispersal by water. It is not clear whether
the nucellus and integument were originally connected or laterally free: the
lacunae may be the remains of an inner flesh and not spaces in a spongy
tissue. The genus is radiospermic and characterised by a long micropyle and
a broad pollen-chamber. On the available evidence it is difficult to assign
the specimens to their systematic position, but the genus is probably a
member of the Trigonocarpales.
III. Cardiocarpales.
Platyspermic seeds for the most part belonging to Cordaitalean plants and
agreeing in their plan of organisation, even more closely than the seeds of
the Trigonocarpales, with those of recent Cycads. The nucellus is free
laterally from the integument and there is a series of vascular bundles in the
nucellus. The testa consists of an outer flesh, the sarcotesta, which may
reach a considerable thickness, a shell or sclerotesta, and in some genera an
endotesta. In seeds preserved as impressions the sarcotesta often gives them
a winged appearance (Samaropsis). The pollen-chamber is relatively small,
resembling in this respect the chamber in recent Cycads. A central
prolongation of the prothallus-tissue in the form of a blunt column or ‘tent-
pole’ is a characteristic feature; the same feature occurs in seeds of the
Lagenostomales, but in the Cordaitales it resembles more nearly the ‘tent-
pole,’ as it was called by Hirase, in recent Cycadean seeds and in Ginkgo.
The presence of two vascular strands in the sarcotesta in the principal plane
of the seeds is a character shared with the seeds of Cycas: the position and
course of these bundles are useful characters for distinguishing different
types within the group. The microspores are multicellular.
Gaudrya trivalvis Grand’Eury.
The generic name Gaudrya[907] was proposed for two petrified seeds from
the Gard coal-field briefly described as G. trivalvis, the type-species, and G.
lagenaria. The testa of the former species shows signs of splitting along
three equidistant lines; it consists of a sarcotesta enclosing an endotesta
with six longitudinal ribs: Grand’Eury speaks of lacunae between the
endotesta and nucellus which he regards as spaces in a tissue which made
the seed buoyant and facilitated dispersal by water. It is not clear whether
the nucellus and integument were originally connected or laterally free: the
lacunae may be the remains of an inner flesh and not spaces in a spongy
tissue. The genus is radiospermic and characterised by a long micropyle and
a broad pollen-chamber. On the available evidence it is difficult to assign
the specimens to their systematic position, but the genus is probably a
member of the Trigonocarpales.
III. Cardiocarpales.
Platyspermic seeds for the most part belonging to Cordaitalean plants and
agreeing in their plan of organisation, even more closely than the seeds of
the Trigonocarpales, with those of recent Cycads. The nucellus is free
laterally from the integument and there is a series of vascular bundles in the
nucellus. The testa consists of an outer flesh, the sarcotesta, which may
reach a considerable thickness, a shell or sclerotesta, and in some genera an
endotesta. In seeds preserved as impressions the sarcotesta often gives them
a winged appearance (Samaropsis). The pollen-chamber is relatively small,
resembling in this respect the chamber in recent Cycads. A central
prolongation of the prothallus-tissue in the form of a blunt column or ‘tent-
pole’ is a characteristic feature; the same feature occurs in seeds of the
Lagenostomales, but in the Cordaitales it resembles more nearly the ‘tent-
pole,’ as it was called by Hirase, in recent Cycadean seeds and in Ginkgo.
The presence of two vascular strands in the sarcotesta in the principal plane
of the seeds is a character shared with the seeds of Cycas: the position and
course of these bundles are useful characters for distinguishing different
types within the group. The microspores are multicellular.
Page 373
Genera. Cardiocarpus; Cyclospermum; Cycadinocarpus;
Rhabdospermum; Mitrospermum; Diplotesta; Leptocaryon; Taxospermum;
Compsotesta. These generic names are all used in the following pages for
seeds known to possess certain anatomical features; there are also included
in the Cardiocarpales the genera Samaropsis, Cordaicarpus, and
Rhabdocarpus, but it is proposed to limit their use to specimens which
furnish no anatomical data and cannot therefore be assigned with equal
confidence to a section of seeds based on definite morphological characters.
It is certain that some at least of the seeds described under these names
would, if preserved as petrified specimens, be included in one or other of
the genera named above.
There is ample proof that some of these seeds were borne on Cordaitean
plants and that the group as a whole represents the seeds of the
Cordaitales[908]. It is, however, certain that some Platyspermic seeds were
produced by Pteridosperms. No little confusion has been caused by the
employment of the same generic names for petrified seeds and for casts and
impressions affording no evidence as to similarity in anatomical characters.
With a view to avoid the risks necessarily entailed by following this
practice it is suggested that a clearer distinction should be drawn between
genera based primarily on structural features and form-genera. The
following notes on the genera Cardiocarpus, Cordaicarpus, Cyclocarpon,
Cycadinocarpus, Jordania, and Samaropsis, may serve to illustrate some of
the difficulties connected with the terminology of Palaeozoic seeds.
Cardiocarpus. Brongniart[909] proposed the name Cardiocarpon in 1828
for Upper Carboniferous seeds described as compressed lenticular,
cordiform or reniform ‘fruits’ with an acute apex: in his later work[910] he
recognised their true morphological nature and gave an account of some
exceptionally well-preserved examples from Grand’ Croix. Brongniart in
common with other authors believed Cardiocarpus seeds to belong to
Cordaitean plants, a view that in several cases is based on conclusive
evidence. The specimen represented in fig. 501, D, illustrates the
characteristic form of a cast of a Cardiocarpus seed, and the sections shown
in fig. 501, A and B, are from an identical or a very closely allied species.
The generic characters are: (i) the presence of a narrow flattened border or
wing surrounding a platyspermic nucule, (ii) the cordiform base and more
or less pointed apex, (iii) the differentiation of the testa into a sarcotesta and
Rhabdospermum; Mitrospermum; Diplotesta; Leptocaryon; Taxospermum;
Compsotesta. These generic names are all used in the following pages for
seeds known to possess certain anatomical features; there are also included
in the Cardiocarpales the genera Samaropsis, Cordaicarpus, and
Rhabdocarpus, but it is proposed to limit their use to specimens which
furnish no anatomical data and cannot therefore be assigned with equal
confidence to a section of seeds based on definite morphological characters.
It is certain that some at least of the seeds described under these names
would, if preserved as petrified specimens, be included in one or other of
the genera named above.
There is ample proof that some of these seeds were borne on Cordaitean
plants and that the group as a whole represents the seeds of the
Cordaitales[908]. It is, however, certain that some Platyspermic seeds were
produced by Pteridosperms. No little confusion has been caused by the
employment of the same generic names for petrified seeds and for casts and
impressions affording no evidence as to similarity in anatomical characters.
With a view to avoid the risks necessarily entailed by following this
practice it is suggested that a clearer distinction should be drawn between
genera based primarily on structural features and form-genera. The
following notes on the genera Cardiocarpus, Cordaicarpus, Cyclocarpon,
Cycadinocarpus, Jordania, and Samaropsis, may serve to illustrate some of
the difficulties connected with the terminology of Palaeozoic seeds.
Cardiocarpus. Brongniart[909] proposed the name Cardiocarpon in 1828
for Upper Carboniferous seeds described as compressed lenticular,
cordiform or reniform ‘fruits’ with an acute apex: in his later work[910] he
recognised their true morphological nature and gave an account of some
exceptionally well-preserved examples from Grand’ Croix. Brongniart in
common with other authors believed Cardiocarpus seeds to belong to
Cordaitean plants, a view that in several cases is based on conclusive
evidence. The specimen represented in fig. 501, D, illustrates the
characteristic form of a cast of a Cardiocarpus seed, and the sections shown
in fig. 501, A and B, are from an identical or a very closely allied species.
The generic characters are: (i) the presence of a narrow flattened border or
wing surrounding a platyspermic nucule, (ii) the cordiform base and more
or less pointed apex, (iii) the differentiation of the testa into a sarcotesta and
Page 374
sclerotesta free from the nucellus except at the base, (iv) the ‘tent-pole’
prolongation of the prothallus (fig. 510, A, b) and the presence of a fairly
large pollen-chamber, pc, (v) the occurrence of two sets of vascular
bundles, an inner nucellar series and two double vascular strands (fig. 500,
A, v, B) which are given off from the main supply before it reaches the
sclerotesta. The term Cardiocarpus as used by Brongniart signifies a type of
seed possessing both certain anatomical and external characters. The
proposal is to restrict the generic appellation to seeds exhibiting definite
structural features agreeing in essentials with Cardiocarpus sclerotesta and
C. drupaceus.
Cordaicarpus. This name was first employed by Geinitz[911] in the form
Cordaicarpon, the type-species being C. Cordai (fig. 502, C) from the Coal
Measures of Germany, a seed referred by the author of the genus to
Cordaites principalis but, as Kidston has pointed out, there is evidence that
this correlation may be incorrect: there is, however, no doubt as to its
Cordaitean parentage. Specimens included in this genus agree closely with
species of Cardiocarpus, but they are usually described as being
distinguished by the absence of a flat border and by a more rounded and
less cordate base. In the example of Cordaicarpus Cordai shown in fig.
502, C, and in other species assigned by authors to this genus there is a
narrow border and the form of the base is an inconstant character. As
Kidston[912] and other authors point out, there are no definite and constant
characters by which to distinguish Cardiocarpus from Cordaicarpus as
regards the form of the seeds preserved as casts or impressions. A further
account of Cordaicarpus is given on a later page.
Cordaispermum. This designation was formerly adopted by Renault[913]
for seeds having the form and anatomical features of Cardiocarpus which
there is good reason for attributing to Cordaites or to some allied genus. In
view of the fact that the majority of the seeds under consideration are
undoubtedly Cordaitean there is no need to employ this additional generic
name.
Cyclocarpon. Fiedler[914] instituted this term for seeds previously
described by Berger as Cardiocarpon emarginatum (fig. 502, B, now
included in Samaropsis) and added a new species Cyclocarpon
nummularium. Brongniart[915] subsequently described the structure of two
species, C. tenue and C. nummulare, which he referred to Fiedler’s genus,
prolongation of the prothallus (fig. 510, A, b) and the presence of a fairly
large pollen-chamber, pc, (v) the occurrence of two sets of vascular
bundles, an inner nucellar series and two double vascular strands (fig. 500,
A, v, B) which are given off from the main supply before it reaches the
sclerotesta. The term Cardiocarpus as used by Brongniart signifies a type of
seed possessing both certain anatomical and external characters. The
proposal is to restrict the generic appellation to seeds exhibiting definite
structural features agreeing in essentials with Cardiocarpus sclerotesta and
C. drupaceus.
Cordaicarpus. This name was first employed by Geinitz[911] in the form
Cordaicarpon, the type-species being C. Cordai (fig. 502, C) from the Coal
Measures of Germany, a seed referred by the author of the genus to
Cordaites principalis but, as Kidston has pointed out, there is evidence that
this correlation may be incorrect: there is, however, no doubt as to its
Cordaitean parentage. Specimens included in this genus agree closely with
species of Cardiocarpus, but they are usually described as being
distinguished by the absence of a flat border and by a more rounded and
less cordate base. In the example of Cordaicarpus Cordai shown in fig.
502, C, and in other species assigned by authors to this genus there is a
narrow border and the form of the base is an inconstant character. As
Kidston[912] and other authors point out, there are no definite and constant
characters by which to distinguish Cardiocarpus from Cordaicarpus as
regards the form of the seeds preserved as casts or impressions. A further
account of Cordaicarpus is given on a later page.
Cordaispermum. This designation was formerly adopted by Renault[913]
for seeds having the form and anatomical features of Cardiocarpus which
there is good reason for attributing to Cordaites or to some allied genus. In
view of the fact that the majority of the seeds under consideration are
undoubtedly Cordaitean there is no need to employ this additional generic
name.
Cyclocarpon. Fiedler[914] instituted this term for seeds previously
described by Berger as Cardiocarpon emarginatum (fig. 502, B, now
included in Samaropsis) and added a new species Cyclocarpon
nummularium. Brongniart[915] subsequently described the structure of two
species, C. tenue and C. nummulare, which he referred to Fiedler’s genus,
Page 375
and Bertrand[916] has shown that these differ from the genus Cardiocarpus in
the recurrent course of the bundles given off from the chalazal strand as in
the genus Rhabdospermum (cf. fig. 501, E). There are no good grounds for
retaining the designation Cyclocarpon for casts and impressions, as the
specimens so named are indistinguishable from impressions referred to
Cordaicarpus. The generic name Cyclocarpus, retained by Bertrand only
for C. tenuis and C. nummularis simply for anatomical reasons, is now
altered to Cyclospermum on the ground that the designation Cyclocarpon
has been used for impressions affording no information with regard to
anatomical features.
Cycadinocarpus. Renault[917] transferred to this genus Brongniart’s
species Cardiocarpus augustodunensis on the ground that the vascular
system exhibits in a greater degree than the other types included by
Brongniart in Cardiocarpus a resemblance to that in recent cycadean seeds.
Bertrand[918] confirms Renault’s account and retains Cycadinocarpus
augustodunensis as a species worthy of generic distinction. A short account
of this seed is given on a later page.
Jordania. This name was given by Fiedler[919] to compressed ovate-
cordate seeds characterised by a broad membranous border bearing a
superficial resemblance to the seeds of Bignonia. The type-species, J.
bignoniodes (fig. 502, I), from the Coal Measures of Saarbrücken has the
form usually associated with the designation Samaropsis, and as the latter
term is generally adopted there are no adequate reasons for the retention of
Jordania. The name Jordania has also been applied, by Schenk[920], to fossil
Dicotyledonous wood and was previously used by Boissier[921].
Samaropsis. Goeppert[922] defined Samaropsis as ‘Fructus samaroideus
membranaceus, compressus, margine alatus, monospermus.’ The type-
species, S. ulmiformis, from the Permian of Brenau, is a small seed with a
broad wing or border, but a better example of Samaropsis is figured by
Goeppert as the wing of an insect[923]. Examples of the genus are shown in
figs. 502, A–H; 503; 504. Seeds included in Samaropsis differ from those
referred to Cordaicarpus in the presence of a broader and more clearly
defined border which in some cases, as in the genus Mitrospermum (fig.
494, K, L), undoubtedly represents a lateral wing-like extension of the
sarcotesta. In some instances the wing may be a tangentially expanded
integument comparable with the perianth of Welwitschia, and in some
the recurrent course of the bundles given off from the chalazal strand as in
the genus Rhabdospermum (cf. fig. 501, E). There are no good grounds for
retaining the designation Cyclocarpon for casts and impressions, as the
specimens so named are indistinguishable from impressions referred to
Cordaicarpus. The generic name Cyclocarpus, retained by Bertrand only
for C. tenuis and C. nummularis simply for anatomical reasons, is now
altered to Cyclospermum on the ground that the designation Cyclocarpon
has been used for impressions affording no information with regard to
anatomical features.
Cycadinocarpus. Renault[917] transferred to this genus Brongniart’s
species Cardiocarpus augustodunensis on the ground that the vascular
system exhibits in a greater degree than the other types included by
Brongniart in Cardiocarpus a resemblance to that in recent cycadean seeds.
Bertrand[918] confirms Renault’s account and retains Cycadinocarpus
augustodunensis as a species worthy of generic distinction. A short account
of this seed is given on a later page.
Jordania. This name was given by Fiedler[919] to compressed ovate-
cordate seeds characterised by a broad membranous border bearing a
superficial resemblance to the seeds of Bignonia. The type-species, J.
bignoniodes (fig. 502, I), from the Coal Measures of Saarbrücken has the
form usually associated with the designation Samaropsis, and as the latter
term is generally adopted there are no adequate reasons for the retention of
Jordania. The name Jordania has also been applied, by Schenk[920], to fossil
Dicotyledonous wood and was previously used by Boissier[921].
Samaropsis. Goeppert[922] defined Samaropsis as ‘Fructus samaroideus
membranaceus, compressus, margine alatus, monospermus.’ The type-
species, S. ulmiformis, from the Permian of Brenau, is a small seed with a
broad wing or border, but a better example of Samaropsis is figured by
Goeppert as the wing of an insect[923]. Examples of the genus are shown in
figs. 502, A–H; 503; 504. Seeds included in Samaropsis differ from those
referred to Cordaicarpus in the presence of a broader and more clearly
defined border which in some cases, as in the genus Mitrospermum (fig.
494, K, L), undoubtedly represents a lateral wing-like extension of the
sarcotesta. In some instances the wing may be a tangentially expanded
integument comparable with the perianth of Welwitschia, and in some
Page 376
Jurassic seeds referred by Heer[924] to Samaropsis the
lateral appendages are probably true wings. It is
advisable to restrict the designation Samaropsis to
Palaeozoic seeds. Nucules deprived of the broad
border would be referred to Cordaicarpus as usually
employed for impressions. The generic name
Samaropsis serves a useful purpose as a distinctive
term for platyspermic seeds preserved as casts or
impressions characterised by the possession of a wide
border or wing broader than in typical examples of Fig. 499.
Cordaicarpus. The specimen represented in fig. 499 Samaropsis
affords a good illustration of the difference between emarginata, from
Samaropsis and Cordaicarpus. In this specimen the the Westphalian
border clearly consists of two portions, an inner series, Yorkshire.
narrower border (black in the drawing) and an outer (Kidston Coll.,
more delicate portion; the former is the impression of 4227; × 2.)
the sclerotesta and the outer represents the fleshy
sarcotesta which in the living seed may have formed a wing. If, as often
happens, the seed were preserved with the narrow border only it would be
assigned to Cordaicarpus, many species of which are undoubtedly
incomplete Samaropsis seeds.
The seeds described by Lindley and Hutton as Cardiocarpon acutum (fig.
444, p. 171) have been made by Arber[925] the type of a new genus
Cornucarpus, the distinguishing feature being the triangular form and the
apical horns of the wing. The seeds figured by Arber[926] from the Kent
coalfield as Cornucarpus acutus are, however, not identical with the type of
Lindley and Hutton, which has the characters of Samaropsis. Samaropsis is
widely distributed in Permo-Carboniferous rocks in Europe and North
America and is recorded also from India[927] (fig. 504), China[928], South
Africa[929] (fig. 503), South America[930] (fig. 502, F, G) and Australia[931].
Some seeds of this form were certainly borne on Cordaitean plants (cf. fig.
480, A), but seeds of similar type have been found in organic connexion
with the foliage of Pteridosperms (figs. 442, 445, pp. 167, 172). The
Permian ‘cone-scales’ bearing seeds described by Geinitz as Cardiocarpon
triangulare[932], represented by well preserved impressions in the Dresden
Museum, appear to be of the Samaropsis type: the same author referred
some Samaropsis seeds to the Conifer Walchia, but Weiss[933] dissents from
lateral appendages are probably true wings. It is
advisable to restrict the designation Samaropsis to
Palaeozoic seeds. Nucules deprived of the broad
border would be referred to Cordaicarpus as usually
employed for impressions. The generic name
Samaropsis serves a useful purpose as a distinctive
term for platyspermic seeds preserved as casts or
impressions characterised by the possession of a wide
border or wing broader than in typical examples of Fig. 499.
Cordaicarpus. The specimen represented in fig. 499 Samaropsis
affords a good illustration of the difference between emarginata, from
Samaropsis and Cordaicarpus. In this specimen the the Westphalian
border clearly consists of two portions, an inner series, Yorkshire.
narrower border (black in the drawing) and an outer (Kidston Coll.,
more delicate portion; the former is the impression of 4227; × 2.)
the sclerotesta and the outer represents the fleshy
sarcotesta which in the living seed may have formed a wing. If, as often
happens, the seed were preserved with the narrow border only it would be
assigned to Cordaicarpus, many species of which are undoubtedly
incomplete Samaropsis seeds.
The seeds described by Lindley and Hutton as Cardiocarpon acutum (fig.
444, p. 171) have been made by Arber[925] the type of a new genus
Cornucarpus, the distinguishing feature being the triangular form and the
apical horns of the wing. The seeds figured by Arber[926] from the Kent
coalfield as Cornucarpus acutus are, however, not identical with the type of
Lindley and Hutton, which has the characters of Samaropsis. Samaropsis is
widely distributed in Permo-Carboniferous rocks in Europe and North
America and is recorded also from India[927] (fig. 504), China[928], South
Africa[929] (fig. 503), South America[930] (fig. 502, F, G) and Australia[931].
Some seeds of this form were certainly borne on Cordaitean plants (cf. fig.
480, A), but seeds of similar type have been found in organic connexion
with the foliage of Pteridosperms (figs. 442, 445, pp. 167, 172). The
Permian ‘cone-scales’ bearing seeds described by Geinitz as Cardiocarpon
triangulare[932], represented by well preserved impressions in the Dresden
Museum, appear to be of the Samaropsis type: the same author referred
some Samaropsis seeds to the Conifer Walchia, but Weiss[933] dissents from
Page 377
this correlation as the seeds often occur in beds in which Walchia is not
represented. Renault states that the seeds of the fertile shoot described by
him as Cycadospadix Milleryensis[934] from Autun [= Strobilites
Milleryensis (Ren.)] closely resemble Samaropsis fluitans Daws. as figured
by Weiss. The suggestion by White[935] that Samaropsis seeds were borne on
fertile leaves of Gangamopteris adds a further difficulty to the use of the
generic characters of Samaropsis as criteria of systematic position. The
Permian seeds figured by Goeppert[936] as Oreodoxites Martianus are
possibly specimens of Samaropsis.
The designation Samaropsis, though usually restricted to Palaeozoic
species, is applied by some authors to ‘winged’ seeds from Mesozoic strata;
but as some of the Jurassic seeds[937] so named appear to have true wings
like those of some recent Conifers it is advisable to adhere to the more
limited use of the name.
It is safe to assert that many Samaropsis seeds agreed generally in
structure with Cordaitean seeds such as the petrified examples described by
Brongniart as Cardiocarpus. The species Mitrospermum compressum[938] is
an example of a petrified seed having the external features of Samaropsis.
Cardiocarpus.
This generic title I propose to restrict to petrified seeds exhibiting the
characters described by Brongniart[939] and more recently by Bertrand[940] in
C. sclerotesta and C. drupaceus. In general organisation seeds of this
generic type agree with those of recent Cycads and with the seed of Ginkgo
biloba, but there are certain distinguishing features. An important character
is afforded by the course and place of origin of the lower vascular strands
from the main supply at the base of the seed. The outer vascular system
consists of two bundles given off from the main strand, before it reaches the
sclerotesta, which pass up the sarcotesta (fig. 500, B). In Rhabdospermum,
on the other hand, the corresponding bundles arise at a higher level and
form recurrent strands which penetrate the sclerotesta before passing up the
fleshy part of the integument (cf. fig. 501, E).
Cardiocarpus sclerotesta Brongniart. The testa is differentiated into an
inner shell and an outer sarcotesta (fig. 501, A; the sclerotesta is shown in
black); there is a well developed pollen-chamber (pc) and below this the
represented. Renault states that the seeds of the fertile shoot described by
him as Cycadospadix Milleryensis[934] from Autun [= Strobilites
Milleryensis (Ren.)] closely resemble Samaropsis fluitans Daws. as figured
by Weiss. The suggestion by White[935] that Samaropsis seeds were borne on
fertile leaves of Gangamopteris adds a further difficulty to the use of the
generic characters of Samaropsis as criteria of systematic position. The
Permian seeds figured by Goeppert[936] as Oreodoxites Martianus are
possibly specimens of Samaropsis.
The designation Samaropsis, though usually restricted to Palaeozoic
species, is applied by some authors to ‘winged’ seeds from Mesozoic strata;
but as some of the Jurassic seeds[937] so named appear to have true wings
like those of some recent Conifers it is advisable to adhere to the more
limited use of the name.
It is safe to assert that many Samaropsis seeds agreed generally in
structure with Cordaitean seeds such as the petrified examples described by
Brongniart as Cardiocarpus. The species Mitrospermum compressum[938] is
an example of a petrified seed having the external features of Samaropsis.
Cardiocarpus.
This generic title I propose to restrict to petrified seeds exhibiting the
characters described by Brongniart[939] and more recently by Bertrand[940] in
C. sclerotesta and C. drupaceus. In general organisation seeds of this
generic type agree with those of recent Cycads and with the seed of Ginkgo
biloba, but there are certain distinguishing features. An important character
is afforded by the course and place of origin of the lower vascular strands
from the main supply at the base of the seed. The outer vascular system
consists of two bundles given off from the main strand, before it reaches the
sclerotesta, which pass up the sarcotesta (fig. 500, B). In Rhabdospermum,
on the other hand, the corresponding bundles arise at a higher level and
form recurrent strands which penetrate the sclerotesta before passing up the
fleshy part of the integument (cf. fig. 501, E).
Cardiocarpus sclerotesta Brongniart. The testa is differentiated into an
inner shell and an outer sarcotesta (fig. 501, A; the sclerotesta is shown in
black); there is a well developed pollen-chamber (pc) and below this the
Page 378
prothallus-tissue is prolonged as a blunt and
short tent-pole, b, as in Gingko and in several
fossil seeds. On each side of the apical tent-pole
the slightly shrunken prothallus shows two
small archegonia, a, which in the relatively
small size and spherical form of the egg-cells
resemble those of Ginkgo. In transverse section
(fig. 501, B) the seed is bi-convex and at each
end of the major axis the sclerotesta forms a
small keel. There are two sets of vascular
bundles concerned in the supply of material to
the ovule; a lower pair of bundles given off
from the central strand in the sarcotesta (fig.
500, B) which pass to the apical region in the Fig. 500. Cardiocarpus
inner tissues of the sarcotesta in the principal drupaceus var.
plane (fig. 500, A, v), and an inner set of expansus. A, transverse
bundles that pass up the peripheral tissue of the section of the testa
nucellus. approximately in the
middle of the seed; v,
The species described by Brongniart as vascular bundles. B,
Cardiocarpus (Cyclocarpus) tenuis and C. diagrammatic sketch,
nummularis have been removed by Bertrand[941] adapted from
from Cardiocarpus on the ground that the Brongniart’s drawing
integumental bundles pursue a course like that of the base of the seed
in Rhabdospermum; it is now referred to the showing the sarcotesta,
new genus Cyclospermum[942]. sa, the sclerotesta, sc,
and the pad of
vascular tissue, d, at
the base of the
nucellus. (After
Brongniart.)
short tent-pole, b, as in Gingko and in several
fossil seeds. On each side of the apical tent-pole
the slightly shrunken prothallus shows two
small archegonia, a, which in the relatively
small size and spherical form of the egg-cells
resemble those of Ginkgo. In transverse section
(fig. 501, B) the seed is bi-convex and at each
end of the major axis the sclerotesta forms a
small keel. There are two sets of vascular
bundles concerned in the supply of material to
the ovule; a lower pair of bundles given off
from the central strand in the sarcotesta (fig.
500, B) which pass to the apical region in the Fig. 500. Cardiocarpus
inner tissues of the sarcotesta in the principal drupaceus var.
plane (fig. 500, A, v), and an inner set of expansus. A, transverse
bundles that pass up the peripheral tissue of the section of the testa
nucellus. approximately in the
middle of the seed; v,
The species described by Brongniart as vascular bundles. B,
Cardiocarpus (Cyclocarpus) tenuis and C. diagrammatic sketch,
nummularis have been removed by Bertrand[941] adapted from
from Cardiocarpus on the ground that the Brongniart’s drawing
integumental bundles pursue a course like that of the base of the seed
in Rhabdospermum; it is now referred to the showing the sarcotesta,
new genus Cyclospermum[942]. sa, the sclerotesta, sc,
and the pad of
vascular tissue, d, at
the base of the
nucellus. (After
Brongniart.)
Page 379
Fig. 500. A, Cardiocarpus sclerotesta in longitudinal section; pc, pollen-
chamber, b, tent-pole, a, archegonia. B, transverse section; a,
archegonia. D, cast of the same or a similar type of seed. C, E,
Rhabdospermum cyclocaryon, longitudinal section and a
diagrammatic sketch of the seed-base; m, micropyle; b, tent-pole;
a, archegonium. (A, B, C, after Brongniart; D, after Renault and
Zeiller; E, adapted from Brongniart.)
Cyclospermum. Gen. nov. (= Cyclocarpus Bertrand).
As stated on a previous page Bertrand[943] re-establishes the generic name
Cyclocarpus, founded on impressions without reference to anatomical
characters, for two petrified seeds from St Étienne described by Brongniart
as Cardiocarpus tenuis and Cyclocarpus nummularis[944]. These types differ
chamber, b, tent-pole, a, archegonia. B, transverse section; a,
archegonia. D, cast of the same or a similar type of seed. C, E,
Rhabdospermum cyclocaryon, longitudinal section and a
diagrammatic sketch of the seed-base; m, micropyle; b, tent-pole;
a, archegonium. (A, B, C, after Brongniart; D, after Renault and
Zeiller; E, adapted from Brongniart.)
Cyclospermum. Gen. nov. (= Cyclocarpus Bertrand).
As stated on a previous page Bertrand[943] re-establishes the generic name
Cyclocarpus, founded on impressions without reference to anatomical
characters, for two petrified seeds from St Étienne described by Brongniart
as Cardiocarpus tenuis and Cyclocarpus nummularis[944]. These types differ
Page 380
from Rhabdospermum in the absence of an apical snout but agree with that
genus in the steeply descending course of the vascular strands in the basal
region of the seed. As stated on a previous page, the name Cyclospermum is
proposed as a substitute for Cyclocarpus because of the employment of the
latter term for impressions.
Cycadinocarpus. Schimper[945].
Cycadinocarpus augustudunensis (Brongniart[946]). In the possession of
two sets of vascular bundles this type agrees with Cardiocarpus, but the
more internal strands pass up on the inner face of the sclerotesta without
penetrating into the nucellus, a feature in which Cycadinocarpus agrees
with the majority of recent cycadean seeds: the outer bundles are given off
from the main supply after it has entered the sclerotesta and not before as in
Cardiocarpus; they follow an oblique course in the sclerotesta and emerge
into the sarcotesta at the shoulders of the basal curve of the seed. As in
Cardiocarpus and Rhabdospermum the two outer bundles lie in the
principal plane of the seed. There is a pollen-chamber at the apex of the
nucellus and the latter tissue is prolonged as a tent-pole which engages with
the micropyle. In the absence of data as to the course of the vascular
bundles in the chalazal region it would not be possible to distinguish
between this genus and Cardiocarpus.
Rhabdocarpus Berger and Rhabdospermum gen. nov.
It is proposed to restrict the name Rhabdocarpus[947] to impressions and
casts of seeds of the type represented by R. tunicatus as figured by
Berger[948] and reproduced in fig. 506, K, the term Rhabdospermum being
applied to seeds of similar form in which are shown certain distinguishing
anatomical features. Rhabdocarpus tunicatus Berger is a species founded on
a specimen from the Coal Measures of Silesia characterised by an outer
carbonised testa prolonged apically as a blunt snout and, as seen in fig. 506,
K, covering an apparently ribbed nucule, but the ‘ribs’ are due to the
presence of fibrous strands and are not ribs in the ordinary sense. The outer
tissue shows numerous longitudinal striations due presumably to the
presence of fibrous elements in the sarcotesta like those shown in the
petrified seed represented in fig. 501, C. The genus is defined by Berger as
genus in the steeply descending course of the vascular strands in the basal
region of the seed. As stated on a previous page, the name Cyclospermum is
proposed as a substitute for Cyclocarpus because of the employment of the
latter term for impressions.
Cycadinocarpus. Schimper[945].
Cycadinocarpus augustudunensis (Brongniart[946]). In the possession of
two sets of vascular bundles this type agrees with Cardiocarpus, but the
more internal strands pass up on the inner face of the sclerotesta without
penetrating into the nucellus, a feature in which Cycadinocarpus agrees
with the majority of recent cycadean seeds: the outer bundles are given off
from the main supply after it has entered the sclerotesta and not before as in
Cardiocarpus; they follow an oblique course in the sclerotesta and emerge
into the sarcotesta at the shoulders of the basal curve of the seed. As in
Cardiocarpus and Rhabdospermum the two outer bundles lie in the
principal plane of the seed. There is a pollen-chamber at the apex of the
nucellus and the latter tissue is prolonged as a tent-pole which engages with
the micropyle. In the absence of data as to the course of the vascular
bundles in the chalazal region it would not be possible to distinguish
between this genus and Cardiocarpus.
Rhabdocarpus Berger and Rhabdospermum gen. nov.
It is proposed to restrict the name Rhabdocarpus[947] to impressions and
casts of seeds of the type represented by R. tunicatus as figured by
Berger[948] and reproduced in fig. 506, K, the term Rhabdospermum being
applied to seeds of similar form in which are shown certain distinguishing
anatomical features. Rhabdocarpus tunicatus Berger is a species founded on
a specimen from the Coal Measures of Silesia characterised by an outer
carbonised testa prolonged apically as a blunt snout and, as seen in fig. 506,
K, covering an apparently ribbed nucule, but the ‘ribs’ are due to the
presence of fibrous strands and are not ribs in the ordinary sense. The outer
tissue shows numerous longitudinal striations due presumably to the
presence of fibrous elements in the sarcotesta like those shown in the
petrified seed represented in fig. 501, C. The genus is defined by Berger as
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follows: ‘Semina ovata vel elliptico-oblonga secundum longitudinem
parallele nervosa vel tenuissime striata, putamine (interdum deficiente)
instructa.’ As used by Berger and many other authors Rhabdocarpus
includes a miscellaneous collection of seeds often differing widely from the
type-species. Many of the examples correctly referred to Berger’s genus are
platyspermic though a bilateral symmetry is by no means always clear.
Renault and Zeiller[949] in their definition of Rhabdocarpus include bilateral
symmetry as a characteristic feature and speak of the seeds as oblong or
oval with a pointed or truncate apex and a rounded base. Impressions of
Rhabdocarpus differ from those of Cardiocarpus or Cordaicarpus in their
more elongate form, always longer than broad, and in the absence of a basal
sinus. The seeds found attached to Neuropteris pinnae and, in external
features, agreeing with many specimens included in Berger’s genus, have
been transferred by P. Bertrand[950] and Arber[951] to a new genus
Neurospermum[952]. Arber[953] in his recent revision of British seeds proposes
to restrict the name Rhabdocarpus to platyspermic seeds having a ‘large
unsymmetrical nucule enclosed in a large unsymmetrical wing or
sarcotesta,’ that is to forms symmetrical in one plane. In this category he
includes Rhabdocarpus tunicatus Berg. (fig. 506, K) and R. subtunicatus[954]
Grand’Eury, but it is not clear on what grounds Berger’s species is spoken
of as symmetrical in only one plane: in the species R. Lilleanus Arb.[955] the
symmetry is hardly sufficiently well defined to rank as a generic character.
In the case of the Neuropteris seeds the apical snout is slightly curved, thus
giving them an unsymmetrical appearance (cf. fig. 422, p. 114). The
Carboniferous and Permian seeds usually referred to Rhabdocarpus are
transferred by Arber to his genus Platyspermum[956], a designation for which
it is proposed to substitute Nathorst’s genus Holcospermum[957]. In seeds
preserved as more or less flattened impressions it is practically impossible
in many cases accurately to determine the symmetry: as fig. 506, A, shows,
casts indistinguishable from some examples of Platyspermum are radially
symmetrical. Brongniart[958] extended the original definition of
Rhabdocarpus to include certain anatomical characters, and these have been
more fully defined by Bertrand[959]. It is for seeds showing these anatomical
features that the name Rhabdospermum is now proposed. This course is
followed on the ground that it is advisable to avoid confusion between
petrified specimens and impressions which in spite of superficial
resemblance may not be closely related. In some cases it is practically
parallele nervosa vel tenuissime striata, putamine (interdum deficiente)
instructa.’ As used by Berger and many other authors Rhabdocarpus
includes a miscellaneous collection of seeds often differing widely from the
type-species. Many of the examples correctly referred to Berger’s genus are
platyspermic though a bilateral symmetry is by no means always clear.
Renault and Zeiller[949] in their definition of Rhabdocarpus include bilateral
symmetry as a characteristic feature and speak of the seeds as oblong or
oval with a pointed or truncate apex and a rounded base. Impressions of
Rhabdocarpus differ from those of Cardiocarpus or Cordaicarpus in their
more elongate form, always longer than broad, and in the absence of a basal
sinus. The seeds found attached to Neuropteris pinnae and, in external
features, agreeing with many specimens included in Berger’s genus, have
been transferred by P. Bertrand[950] and Arber[951] to a new genus
Neurospermum[952]. Arber[953] in his recent revision of British seeds proposes
to restrict the name Rhabdocarpus to platyspermic seeds having a ‘large
unsymmetrical nucule enclosed in a large unsymmetrical wing or
sarcotesta,’ that is to forms symmetrical in one plane. In this category he
includes Rhabdocarpus tunicatus Berg. (fig. 506, K) and R. subtunicatus[954]
Grand’Eury, but it is not clear on what grounds Berger’s species is spoken
of as symmetrical in only one plane: in the species R. Lilleanus Arb.[955] the
symmetry is hardly sufficiently well defined to rank as a generic character.
In the case of the Neuropteris seeds the apical snout is slightly curved, thus
giving them an unsymmetrical appearance (cf. fig. 422, p. 114). The
Carboniferous and Permian seeds usually referred to Rhabdocarpus are
transferred by Arber to his genus Platyspermum[956], a designation for which
it is proposed to substitute Nathorst’s genus Holcospermum[957]. In seeds
preserved as more or less flattened impressions it is practically impossible
in many cases accurately to determine the symmetry: as fig. 506, A, shows,
casts indistinguishable from some examples of Platyspermum are radially
symmetrical. Brongniart[958] extended the original definition of
Rhabdocarpus to include certain anatomical characters, and these have been
more fully defined by Bertrand[959]. It is for seeds showing these anatomical
features that the name Rhabdospermum is now proposed. This course is
followed on the ground that it is advisable to avoid confusion between
petrified specimens and impressions which in spite of superficial
resemblance may not be closely related. In some cases it is practically
Page 382
certain that an impression of the Rhabdocarpus type is generically identical
with a seed of similar form showing the anatomical structure of
Rhabdospermum, but unless identity is established a distinct terminology is
preferable. The use of the generic name Rhabdospermum carries with it an
implication of platyspermy, but under Rhabdocarpus may be included seeds
which are radiospermic and platyspermic. Some seeds agreeing with
Rhabdospermum are referred by Grand’Eury[960] to Poroxylon, and it is
probable that Rhabdospermum like Cardiocarpus is a Cordaitean seed. On
the other hand Rhabdocarpus may well include species, apart from those
transferred to Neurospermum, that belong to Pteridosperms. A species,
Rhabdocarpus Oliveri, recently described by Kidston[961] from the
Staffordshire coalfield is an example of a radiospermic seed which may be
assigned to a Pteridosperm. The type-specimen is an ovate seed 4 cm. long
and 2 cm. broad agreeing in form and surface-features with Rhabdocarpus
as already defined, but the evidence it affords of internal structure is
insufficient to determine its position with regard to genera founded on
anatomical characters. Other examples of Rhabdocarpus are described by
Lesquereux[962] and White[963] from American Coal Measures, by
Grand’Eury[964] from the Loire, by Renault[965] from Autun, and by many
other authors.
Rhabdospermum. Gen. nov.
The platyspermic seeds included in this genus agree in size and form
with impressions assigned to Rhabdocarpus and as regards the main
features conform anatomically to Cardiocarpus; they were probably borne
on Cordaitean plants. Fig. 501, C, represents a longitudinal section of the
species Rhabdospermum cyclocaryon described by Brongniart as
Rhabdocarpus cyclocaryon: the sarcotesta is particularly well developed in
the apical region; at the apex a portion of the micropyle is seen at m and
near the nucellus are pieces of the sclerotesta shown in black. The presence
of anastomosing fibres near the surface is a characteristic feature: these, as
Bertrand points out, do not form a hypodermal tissue in the strict sense as
they may be separated by some of the thin-walled parenchyma of the
sarcotesta from the epidermis. The sclerotesta is only partially preserved but
the inner portion forms a dark line enclosing the nucellus, the superficial
tissue of which is separated from the shrunken prothallus represented by the
with a seed of similar form showing the anatomical structure of
Rhabdospermum, but unless identity is established a distinct terminology is
preferable. The use of the generic name Rhabdospermum carries with it an
implication of platyspermy, but under Rhabdocarpus may be included seeds
which are radiospermic and platyspermic. Some seeds agreeing with
Rhabdospermum are referred by Grand’Eury[960] to Poroxylon, and it is
probable that Rhabdospermum like Cardiocarpus is a Cordaitean seed. On
the other hand Rhabdocarpus may well include species, apart from those
transferred to Neurospermum, that belong to Pteridosperms. A species,
Rhabdocarpus Oliveri, recently described by Kidston[961] from the
Staffordshire coalfield is an example of a radiospermic seed which may be
assigned to a Pteridosperm. The type-specimen is an ovate seed 4 cm. long
and 2 cm. broad agreeing in form and surface-features with Rhabdocarpus
as already defined, but the evidence it affords of internal structure is
insufficient to determine its position with regard to genera founded on
anatomical characters. Other examples of Rhabdocarpus are described by
Lesquereux[962] and White[963] from American Coal Measures, by
Grand’Eury[964] from the Loire, by Renault[965] from Autun, and by many
other authors.
Rhabdospermum. Gen. nov.
The platyspermic seeds included in this genus agree in size and form
with impressions assigned to Rhabdocarpus and as regards the main
features conform anatomically to Cardiocarpus; they were probably borne
on Cordaitean plants. Fig. 501, C, represents a longitudinal section of the
species Rhabdospermum cyclocaryon described by Brongniart as
Rhabdocarpus cyclocaryon: the sarcotesta is particularly well developed in
the apical region; at the apex a portion of the micropyle is seen at m and
near the nucellus are pieces of the sclerotesta shown in black. The presence
of anastomosing fibres near the surface is a characteristic feature: these, as
Bertrand points out, do not form a hypodermal tissue in the strict sense as
they may be separated by some of the thin-walled parenchyma of the
sarcotesta from the epidermis. The sclerotesta is only partially preserved but
the inner portion forms a dark line enclosing the nucellus, the superficial
tissue of which is separated from the shrunken prothallus represented by the
Page 383
almost spherical dotted region: the remains of an archegonium are seen at a
(fig. 501, C) and the characteristic tent-pole apex of the prothallus is shown
at b. While in shape and in the general plan of organisation
Rhabdospermum agrees with Cardiocarpus, the vascular system in the
chalazal region constitutes a distinguishing feature. In Rhabdospermum the
main vascular strand passes through the sclerotesta, e, e′, fig. 501, E, before
giving off two bundles which bend back (‘faisceaux récurrents’), traverse
the shell, and then pass up the sarcotesta in correspondence with the feebly
developed lateral keels as far as the micropyle, while in Cardiocarpus (fig.
500, B) the bundles are given off before the main strand reaches the
sclerotesta. Similar recurrent bundles occur also in Mitrospermum (fig. 494,
K)[967].
Mitrospermum. A. Arber.
Mitrospermum compressum (Williamson). Mrs Arber[968] proposed the
name Mitrospermum[969], suggested by the peculiar form of the seed-base, as
a substitute for Cardiocarpon for Williamson’s species C. compressum[970]
from the Lower Coal Measures of Lancashire. The seed is platyspermic and
there is some evidence that it split into two valves along the principal plane
(the longer axis of the section, fig. 494, L). The diagrammatic and partially
restored longitudinal section reproduced in fig. 494, K, shows the main
features: a sarcotesta, sa, covers the surface of the testa as a thin layer
except at the edges of the flattened sides where it forms a wing-like border;
preserved as an impression the seed would be assigned to Samaropsis. The
sclerotesta, sc, has a pointed apex which surrounds the lower third of the
micropyle and a broad base perforated by the chalazal vascular strand.
There was probably a narrow inner flesh as in Trigonocarpus and recent
Cycadean seeds (fig. 494, K, cf). The nucellus was free from the integument
except at the base, as in Trigonocarpus and Stephanospermum (fig. 494, K,
n): internal to the shrivelled remains of the inner flesh there was a nucellar
tapetum surrounding the megaspore. Details as to the pollen-chamber are
lacking though there are indications that it resembled that of some species
of Cordaitean seeds. The main vascular supply passes through the
sclerotesta and then forms a low cushion of short reticulate elements below
the base of the nucellus from which two bundles are given off (fig. 494, K,
v) in the principal plane. The course of the bundles which pierce the
(fig. 501, C) and the characteristic tent-pole apex of the prothallus is shown
at b. While in shape and in the general plan of organisation
Rhabdospermum agrees with Cardiocarpus, the vascular system in the
chalazal region constitutes a distinguishing feature. In Rhabdospermum the
main vascular strand passes through the sclerotesta, e, e′, fig. 501, E, before
giving off two bundles which bend back (‘faisceaux récurrents’), traverse
the shell, and then pass up the sarcotesta in correspondence with the feebly
developed lateral keels as far as the micropyle, while in Cardiocarpus (fig.
500, B) the bundles are given off before the main strand reaches the
sclerotesta. Similar recurrent bundles occur also in Mitrospermum (fig. 494,
K)[967].
Mitrospermum. A. Arber.
Mitrospermum compressum (Williamson). Mrs Arber[968] proposed the
name Mitrospermum[969], suggested by the peculiar form of the seed-base, as
a substitute for Cardiocarpon for Williamson’s species C. compressum[970]
from the Lower Coal Measures of Lancashire. The seed is platyspermic and
there is some evidence that it split into two valves along the principal plane
(the longer axis of the section, fig. 494, L). The diagrammatic and partially
restored longitudinal section reproduced in fig. 494, K, shows the main
features: a sarcotesta, sa, covers the surface of the testa as a thin layer
except at the edges of the flattened sides where it forms a wing-like border;
preserved as an impression the seed would be assigned to Samaropsis. The
sclerotesta, sc, has a pointed apex which surrounds the lower third of the
micropyle and a broad base perforated by the chalazal vascular strand.
There was probably a narrow inner flesh as in Trigonocarpus and recent
Cycadean seeds (fig. 494, K, cf). The nucellus was free from the integument
except at the base, as in Trigonocarpus and Stephanospermum (fig. 494, K,
n): internal to the shrivelled remains of the inner flesh there was a nucellar
tapetum surrounding the megaspore. Details as to the pollen-chamber are
lacking though there are indications that it resembled that of some species
of Cordaitean seeds. The main vascular supply passes through the
sclerotesta and then forms a low cushion of short reticulate elements below
the base of the nucellus from which two bundles are given off (fig. 494, K,
v) in the principal plane. The course of the bundles which pierce the
Page 384
sclerotesta led Mrs Arber to remove this seed from Cardiocarpus, as
recently defined by Bertrand[971], since in that genus the integumental
bundles have their origin below the sclerotesta. In the course of the vascular
bundles Mitrospermum is intermediate between Rhabdospermum and
Taxospermum.
This genus is founded on a detached seed, but its resemblance to
undoubted Cordaitean species favours its attribution to that group though,
as Mrs Arber points out, some markedly platyspermic seeds are known to
have been borne on fern-like fronds and Mitrospermum may belong to some
genus of Pteridosperms.
Diplotesta. Brongniart.
Diplotesta Grand’Euryana Brongniart. The generic name Diplotesta,
suggested by Grand’Eury, was given by Brongniart[972] to a Grand’ Croix
seed which he compared with that of the Conifer Cephalotaxus. The type-
specimen is elliptical and platyspermic (fig. 495, H, p. 322), and differs
from Taxospermum in the cordate form of the seed-cavity, also in the more
restricted union of nucellus and testa. The testa is differentiated into a
sarcotesta (sa) and sclerotesta, and the latter forms two feebly developed
keels in the principal plane: a characteristic feature shared with
Mitrospermum is the splitting of the shell into two equal valves (fig. 495,
F). Fig. 495, H, shows the contracted cylindrical nucellus and the pollen-
chamber: the sarcotesta (sa) is only partially preserved. Diplotesta differs
from Cardiocarpus in the course of the integumental vascular bundles
which are of the type illustrated by Rhabdospermum, Taxospermum, and
Cyclocarpus, but from these genera it is distinguished by the dehiscence of
the shell, also by its form and certain anatomical features as described by
Brongniart and Bertrand[973].
In this genus Bertrand includes Brongniart’s species Sarcotaxus avellana
(fig. 495, F), a correlation suggested by the latter author.
Leptocaryon. Brongniart.
Brongniart[974] founded this genus for a single species, Leptocaryon
avellana, represented by a Grand’ Croix specimen 12 × 10 mm., which he
recently defined by Bertrand[971], since in that genus the integumental
bundles have their origin below the sclerotesta. In the course of the vascular
bundles Mitrospermum is intermediate between Rhabdospermum and
Taxospermum.
This genus is founded on a detached seed, but its resemblance to
undoubted Cordaitean species favours its attribution to that group though,
as Mrs Arber points out, some markedly platyspermic seeds are known to
have been borne on fern-like fronds and Mitrospermum may belong to some
genus of Pteridosperms.
Diplotesta. Brongniart.
Diplotesta Grand’Euryana Brongniart. The generic name Diplotesta,
suggested by Grand’Eury, was given by Brongniart[972] to a Grand’ Croix
seed which he compared with that of the Conifer Cephalotaxus. The type-
specimen is elliptical and platyspermic (fig. 495, H, p. 322), and differs
from Taxospermum in the cordate form of the seed-cavity, also in the more
restricted union of nucellus and testa. The testa is differentiated into a
sarcotesta (sa) and sclerotesta, and the latter forms two feebly developed
keels in the principal plane: a characteristic feature shared with
Mitrospermum is the splitting of the shell into two equal valves (fig. 495,
F). Fig. 495, H, shows the contracted cylindrical nucellus and the pollen-
chamber: the sarcotesta (sa) is only partially preserved. Diplotesta differs
from Cardiocarpus in the course of the integumental vascular bundles
which are of the type illustrated by Rhabdospermum, Taxospermum, and
Cyclocarpus, but from these genera it is distinguished by the dehiscence of
the shell, also by its form and certain anatomical features as described by
Brongniart and Bertrand[973].
In this genus Bertrand includes Brongniart’s species Sarcotaxus avellana
(fig. 495, F), a correlation suggested by the latter author.
Leptocaryon. Brongniart.
Brongniart[974] founded this genus for a single species, Leptocaryon
avellana, represented by a Grand’ Croix specimen 12 × 10 mm., which he
Page 385
believed to be related to Taxus. Leptocaryon differs from Taxospermum in
the structure of the testa, but resembles it in external features. Bertrand[975]
in his revision and extension of Brongniart’s account says that the sections
throw no light on the nature of the vascular supply, and it is therefore
impossible to form a satisfactory opinion as to the relationships of the
genus. Renault[976] referred this genus to the Cordaitales, but we have no
evidence as to the parent-plant.
Taxospermum. Brongniart.
Brongniart[977] gave this name to a small elliptical seed, 15×9 mm.,
recalling in external features the seed of Taxus, a genus to which he
believed the Grand’ Croix species to be related. The type-species
Taxospermum Grüneri (fig. 495, G) has a comparatively thin testa
characterised by the absence of a sub-chalazal pad formed by the swelling
of the sclerotesta. The nucellus is attached by a broad base to the testa and
the two regions appear to be connected for a short distance on the flanks[978];
in this feature the seed is comparable with that of the Conifer Torreya and
differs from the other platysperms, Diplotesta, Rhabdospermum, etc.
Bertrand[979] states that the main vascular strand extends from the hilum to
the chalaza before giving off the two opposite bundles which ‘follow the
floor of the shell-cavity, and on reaching the flanks traverse the shell
obliquely from below upwards[980].’ In the course and position of the
integumental bundles Taxospermum differs from Cardiocarpus,
Cycadinocarpus, and Rhabdospermum. In this genus Bertrand includes
Sarcotaxus angulosus Brongn. and S. olivaeformis Brongn.[981]
Compsotesta. Bertrand ex Brongniart ms.
Compsotesta Brongniarti Bertrand. The generic name Compsotesta[982],
though adopted by Brongniart for some incomplete specimens from Grand’
Croix, was not published either by him or Renault: it has recently been
revived by Bertrand[983] in his account of the anatomical details of
Brongniart’s sections. This seed appears to be closely allied to the
polypterous forms Ptychotesta and Hexapterospermum: the testa consists of
a sarcotesta differentiated into two zones the outer of which contains
vascular bundles in correspondence with the ribs, and an inner shell. There
the structure of the testa, but resembles it in external features. Bertrand[975]
in his revision and extension of Brongniart’s account says that the sections
throw no light on the nature of the vascular supply, and it is therefore
impossible to form a satisfactory opinion as to the relationships of the
genus. Renault[976] referred this genus to the Cordaitales, but we have no
evidence as to the parent-plant.
Taxospermum. Brongniart.
Brongniart[977] gave this name to a small elliptical seed, 15×9 mm.,
recalling in external features the seed of Taxus, a genus to which he
believed the Grand’ Croix species to be related. The type-species
Taxospermum Grüneri (fig. 495, G) has a comparatively thin testa
characterised by the absence of a sub-chalazal pad formed by the swelling
of the sclerotesta. The nucellus is attached by a broad base to the testa and
the two regions appear to be connected for a short distance on the flanks[978];
in this feature the seed is comparable with that of the Conifer Torreya and
differs from the other platysperms, Diplotesta, Rhabdospermum, etc.
Bertrand[979] states that the main vascular strand extends from the hilum to
the chalaza before giving off the two opposite bundles which ‘follow the
floor of the shell-cavity, and on reaching the flanks traverse the shell
obliquely from below upwards[980].’ In the course and position of the
integumental bundles Taxospermum differs from Cardiocarpus,
Cycadinocarpus, and Rhabdospermum. In this genus Bertrand includes
Sarcotaxus angulosus Brongn. and S. olivaeformis Brongn.[981]
Compsotesta. Bertrand ex Brongniart ms.
Compsotesta Brongniarti Bertrand. The generic name Compsotesta[982],
though adopted by Brongniart for some incomplete specimens from Grand’
Croix, was not published either by him or Renault: it has recently been
revived by Bertrand[983] in his account of the anatomical details of
Brongniart’s sections. This seed appears to be closely allied to the
polypterous forms Ptychotesta and Hexapterospermum: the testa consists of
a sarcotesta differentiated into two zones the outer of which contains
vascular bundles in correspondence with the ribs, and an inner shell. There
Page 386
is a nucellar vascular supply and the nucellus is free on the flanks as in
Stephanospermum and Trigonocarpus.
Samaropsis. Goeppert.
The characters of this Permian and Carboniferous genus have already
been described: the name has reference only to superficial features
especially the samara-like ‘wing,’ and connotes no special anatomical
features.
Samaropsis fluitans (Dawson). The species described by Dawson[984] as
Cardiocarpum fluitans from Carboniferous strata in Nova Scotia, is
represented by oval seeds with a fairly broad border usually showing an
apical notch. Fig. 502, A, is a copy of Dawson’s figure: the apparent
absence of an apical sinus in the ‘wing’ is probably due either to an error in
interpretation or to some imperfection in the specimen. As fig. 502, A,
shows, the type-specimens are far from satisfactory, and it may be that they
are not specifically identical with the more complete specimens from
European strata referred to Dawson’s species. Zeiller[985] points out that
seeds of this species vary considerably in size, but there is always in well-
preserved examples a bifid beak at the apex. Seeds of similar form though
not specifically identical are described from the Coal Measures of Missouri
as Cardiocarpon (Samaropsis) Branneri Fairch. and White[986]. Good
examples of S. fluitans are figured by Weiss[987] from the Coal Measures of
Saarbrücken and the species is widely distributed in Upper Carboniferous
beds generally.
Samaropsis bicaudata Kidston. This species (fig. 502, E) originally
described[988] from Lower Carboniferous rocks in Scotland as Cardiocarpus
bicaudata and subsequently assigned to Samaropsis, is characterised by a
greater development of the flat wing-like border which is divided into two
long tapering basal lobes. Seeds of similar form are figured by
Lesquereux[989] from Pennsylvania as Cardiocarpus (Ptilocarpus)
bicornutus.
Samaropsis (Samarospermum) moravica (Helmhacher). This type[990]
(fig. 502, H) is characterised by the great length of the wing-like border and
on that account it was transferred by Arber to a new genus. It was originally
described by Helmhacher from the Permian of Moravia as Jordania
Stephanospermum and Trigonocarpus.
Samaropsis. Goeppert.
The characters of this Permian and Carboniferous genus have already
been described: the name has reference only to superficial features
especially the samara-like ‘wing,’ and connotes no special anatomical
features.
Samaropsis fluitans (Dawson). The species described by Dawson[984] as
Cardiocarpum fluitans from Carboniferous strata in Nova Scotia, is
represented by oval seeds with a fairly broad border usually showing an
apical notch. Fig. 502, A, is a copy of Dawson’s figure: the apparent
absence of an apical sinus in the ‘wing’ is probably due either to an error in
interpretation or to some imperfection in the specimen. As fig. 502, A,
shows, the type-specimens are far from satisfactory, and it may be that they
are not specifically identical with the more complete specimens from
European strata referred to Dawson’s species. Zeiller[985] points out that
seeds of this species vary considerably in size, but there is always in well-
preserved examples a bifid beak at the apex. Seeds of similar form though
not specifically identical are described from the Coal Measures of Missouri
as Cardiocarpon (Samaropsis) Branneri Fairch. and White[986]. Good
examples of S. fluitans are figured by Weiss[987] from the Coal Measures of
Saarbrücken and the species is widely distributed in Upper Carboniferous
beds generally.
Samaropsis bicaudata Kidston. This species (fig. 502, E) originally
described[988] from Lower Carboniferous rocks in Scotland as Cardiocarpus
bicaudata and subsequently assigned to Samaropsis, is characterised by a
greater development of the flat wing-like border which is divided into two
long tapering basal lobes. Seeds of similar form are figured by
Lesquereux[989] from Pennsylvania as Cardiocarpus (Ptilocarpus)
bicornutus.
Samaropsis (Samarospermum) moravica (Helmhacher). This type[990]
(fig. 502, H) is characterised by the great length of the wing-like border and
on that account it was transferred by Arber to a new genus. It was originally
described by Helmhacher from the Permian of Moravia as Jordania
Page 387
moravica and the type-specimen has been refigured by Zeiller[991] who
records the species from Upper Carboniferous and Permian rocks in France:
it is recorded also from several localities in Germany[992]. Seeds figured by
Potonié[993] from the Permian of Thuringia as Samaropsis Crampii (Hartt)
are undoubtedly examples of S. moravica: the true S. Crampii has recently
been well illustrated by Dr Stopes[994] from the Westphalian of New
Brunswick. The species is recorded by Arber[995] from the Kent coalfield.
Samaropsis emarginata (Goeppert and Barger).
The seed represented in fig. 502, B, from the Lower Coal Measures of
Kilmarnock, Scotland[996], affords a good example of the genus: the species
was originally described by Berger as Cardiocarpon emarginatum and it
was on this type that Fiedler founded the genus Cyclocarpon[997]. It has been
referred by many authors to Cardiocarpon and might be regarded as a type
intermediate between Cordaicarpus, as used in this chapter, and
Samaropsis, though the breadth of the border is more in keeping with the
latter designation. The figured specimen is 1·6 cm. long and 1·4 cm. broad;
the nucule has a slightly cordate base and shows several faint converging
ribs which are too inconspicuous to be represented in a natural-size
drawing. A narrow median groove in the apical region shows the position of
a vascular strand. The species is recorded from several countries: similar
though specifically distinct seeds, described by Dawson as Cardiocarpon
cornutum, have recently been re-described by Dr Stopes[998] from the
Westphalian of New Brunswick where they occur in association with the
leaves of Cordaites Robbii Daws.
records the species from Upper Carboniferous and Permian rocks in France:
it is recorded also from several localities in Germany[992]. Seeds figured by
Potonié[993] from the Permian of Thuringia as Samaropsis Crampii (Hartt)
are undoubtedly examples of S. moravica: the true S. Crampii has recently
been well illustrated by Dr Stopes[994] from the Westphalian of New
Brunswick. The species is recorded by Arber[995] from the Kent coalfield.
Samaropsis emarginata (Goeppert and Barger).
The seed represented in fig. 502, B, from the Lower Coal Measures of
Kilmarnock, Scotland[996], affords a good example of the genus: the species
was originally described by Berger as Cardiocarpon emarginatum and it
was on this type that Fiedler founded the genus Cyclocarpon[997]. It has been
referred by many authors to Cardiocarpon and might be regarded as a type
intermediate between Cordaicarpus, as used in this chapter, and
Samaropsis, though the breadth of the border is more in keeping with the
latter designation. The figured specimen is 1·6 cm. long and 1·4 cm. broad;
the nucule has a slightly cordate base and shows several faint converging
ribs which are too inconspicuous to be represented in a natural-size
drawing. A narrow median groove in the apical region shows the position of
a vascular strand. The species is recorded from several countries: similar
though specifically distinct seeds, described by Dawson as Cardiocarpon
cornutum, have recently been re-described by Dr Stopes[998] from the
Westphalian of New Brunswick where they occur in association with the
leaves of Cordaites Robbii Daws.
Page 388
Fig. 502. A, Samaropsis fluitans. B, Samaropsis emarginata. C, D,
Cordaicarpus Cordai. E, Samaropsis bicaudata. F, Samaropsis
Seixasi. G, Samaropsis barcellosa. H, Samaropsis moravica. I,
Samaropsis bignonioides. K, Samaropsis Newberryi. (A, after
Dawson; B, R. K. 1576; C, R. K. 1899; D, R. K. 4647; E, after
Kidston; F, G, after White; H, after Zeiller; I, after Fiedler; K, R.
K. 2313. All nat. size.)
Samaropsis Newberryi Andrews.
This species was originally described by Andrews[999] from the Coal
Measures of Ohio: the specimen shown in fig. 502, K, was sent to Dr
Kidston by Mr Claypole. The whole seed is 5 cm. wide and 3·5 cm. in
Cordaicarpus Cordai. E, Samaropsis bicaudata. F, Samaropsis
Seixasi. G, Samaropsis barcellosa. H, Samaropsis moravica. I,
Samaropsis bignonioides. K, Samaropsis Newberryi. (A, after
Dawson; B, R. K. 1576; C, R. K. 1899; D, R. K. 4647; E, after
Kidston; F, G, after White; H, after Zeiller; I, after Fiedler; K, R.
K. 2313. All nat. size.)
Samaropsis Newberryi Andrews.
This species was originally described by Andrews[999] from the Coal
Measures of Ohio: the specimen shown in fig. 502, K, was sent to Dr
Kidston by Mr Claypole. The whole seed is 5 cm. wide and 3·5 cm. in
Page 389
depth; it is characterised by a short and relatively broad nucule surrounded
by a very broad and flat border showing faintly marked radially disposed
lines and in places some irregularly distributed pits. The apex is emarginate
and there is a broad and deep sinus in the sarcotesta in the chalazal region.
The seed resembles Samaropsis alata Kidst.[1000] and S. Baileyi (Daws.)[1001]
but it differs from these in the greater breadth of the ‘wing’ and in the form
of the nucule.
The seed described by Fiedler[1002] as Jordania bignonioides (fig. 502, I)
agrees closely with S. alata Kidst. but is probably specifically distinct.
Samaropsis barcellosa (White).
White[1003] described this species (fig. 502, G) from Permo-Carboniferous
rocks in Brazil (Rio Grande do Sul) as Cardiocarpon barcellosum. The
nucule is said to be cordate but, as seen in the figure, there is no clear
indication of a basal sinus: the presence of a relatively broad ‘wing,’ as
White says, entitles the seed ‘to a place in the Samaropsis section of the
genus.’ The author of the species compares it with seeds described from
Westphalian rocks in Ohio[1004] and Pennsylvania[1005]. It is interesting to find
a type which is common in both Europe and North America in the western
portion of Gondwana Land. Seeds of similar form are recorded also from
India, South Africa, and Australia[1006].
Samaropsis Seixasi (White).
This Brazilian species from the same beds is described by White as
Gangamopteris (Samaropsis) Seixasi[1007]: it is characterised by a small
ovate nucule 8–10 mm. long and 5 mm. broad, in some specimens
surrounded by a complete ‘wing’ extending above the apex and below the
base, giving the seed an appearance similar to that of Samaropsis
(Samarospermum) moravica while sometimes, as in the example shown in
fig. 502, F, the broad border is preserved only at the sides. These seeds are
abundant in the Santa Catharina beds, where they were discovered by Dr
Esdras do Prado Seixas, in association with leaves of Gangamopteris, and
White thinks that they were borne on the fertile leaves of that genus which
he has named Arberia[1008]. Although there is as yet no proof of a connexion
between Gangamopteris and seeds of this or any other type it is almost
certain that it was a seed-producing plant.
by a very broad and flat border showing faintly marked radially disposed
lines and in places some irregularly distributed pits. The apex is emarginate
and there is a broad and deep sinus in the sarcotesta in the chalazal region.
The seed resembles Samaropsis alata Kidst.[1000] and S. Baileyi (Daws.)[1001]
but it differs from these in the greater breadth of the ‘wing’ and in the form
of the nucule.
The seed described by Fiedler[1002] as Jordania bignonioides (fig. 502, I)
agrees closely with S. alata Kidst. but is probably specifically distinct.
Samaropsis barcellosa (White).
White[1003] described this species (fig. 502, G) from Permo-Carboniferous
rocks in Brazil (Rio Grande do Sul) as Cardiocarpon barcellosum. The
nucule is said to be cordate but, as seen in the figure, there is no clear
indication of a basal sinus: the presence of a relatively broad ‘wing,’ as
White says, entitles the seed ‘to a place in the Samaropsis section of the
genus.’ The author of the species compares it with seeds described from
Westphalian rocks in Ohio[1004] and Pennsylvania[1005]. It is interesting to find
a type which is common in both Europe and North America in the western
portion of Gondwana Land. Seeds of similar form are recorded also from
India, South Africa, and Australia[1006].
Samaropsis Seixasi (White).
This Brazilian species from the same beds is described by White as
Gangamopteris (Samaropsis) Seixasi[1007]: it is characterised by a small
ovate nucule 8–10 mm. long and 5 mm. broad, in some specimens
surrounded by a complete ‘wing’ extending above the apex and below the
base, giving the seed an appearance similar to that of Samaropsis
(Samarospermum) moravica while sometimes, as in the example shown in
fig. 502, F, the broad border is preserved only at the sides. These seeds are
abundant in the Santa Catharina beds, where they were discovered by Dr
Esdras do Prado Seixas, in association with leaves of Gangamopteris, and
White thinks that they were borne on the fertile leaves of that genus which
he has named Arberia[1008]. Although there is as yet no proof of a connexion
between Gangamopteris and seeds of this or any other type it is almost
certain that it was a seed-producing plant.
Page 390
Samaropsis Leslii sp. nov.
The seed on which this species is founded was
discovered by Mr T. N. Leslie in the Ecca beds
(Permo-Carboniferous) of Vereeniging, South Africa,
a locality from which the same geologist has obtained
leaves of Cordaites, Psygmophyllum, Glossopteris and
other genera[1009]. In the slightly cordate base and
tapered apex (fig. 503) the nucule agrees closely with
those of European examples, but the Vereeniging type
is distinguished by its larger dimensions and by the
wider border indicating a thick sarcotesta continued
basally into a stout stalk. The apex is emarginate and a
median rib marks the position of a vascular strand.
There is no evidence as to the nature of the parent- Fig. 503.
plant. Samaropsis Leslii.
From
Samaropsis indica (Zeiller). Vereeniging, S.
Prof. Zeiller[1010] described this species as Africa. (Mr
Cardiocarpus indicus from the Karharbari (Lower Leslie’s
Gondwana) beds of India. An examination of the type- Collection; nat.
specimens enables me to confirm the accuracy of the size.)
original account. The platyspermic seed is 5·5 cm. long and 4·5 cm. broad;
a cordate nucule is enclosed by a flat border similar to that of Samaropsis
Leslii but narrower especially on the sides of the nucule. At the apex there is
a deep sinus extending to the nucule, and at the base a fairly broad band of
carbonaceous matter shows the position of the chalazal vascular strand. The
seed is characterised by its large size and by its almost orbicular form: it
occurs as a detached specimen in beds containing Cordaites
(Noeggerathiopsis) and Glossopteris.
A species from Arkansas described by Lesquereux[1011] as Cardiocarpus
ingens [= Cordaicarpus ingens (Lesq.)] affords another example of a large
seed similar to C. indicus and, except in its more orbicular form, to
Samaropsis Leslii.
Samaropsis Milleri (Feistmantel).
The seed on which this species is founded was
discovered by Mr T. N. Leslie in the Ecca beds
(Permo-Carboniferous) of Vereeniging, South Africa,
a locality from which the same geologist has obtained
leaves of Cordaites, Psygmophyllum, Glossopteris and
other genera[1009]. In the slightly cordate base and
tapered apex (fig. 503) the nucule agrees closely with
those of European examples, but the Vereeniging type
is distinguished by its larger dimensions and by the
wider border indicating a thick sarcotesta continued
basally into a stout stalk. The apex is emarginate and a
median rib marks the position of a vascular strand.
There is no evidence as to the nature of the parent- Fig. 503.
plant. Samaropsis Leslii.
From
Samaropsis indica (Zeiller). Vereeniging, S.
Prof. Zeiller[1010] described this species as Africa. (Mr
Cardiocarpus indicus from the Karharbari (Lower Leslie’s
Gondwana) beds of India. An examination of the type- Collection; nat.
specimens enables me to confirm the accuracy of the size.)
original account. The platyspermic seed is 5·5 cm. long and 4·5 cm. broad;
a cordate nucule is enclosed by a flat border similar to that of Samaropsis
Leslii but narrower especially on the sides of the nucule. At the apex there is
a deep sinus extending to the nucule, and at the base a fairly broad band of
carbonaceous matter shows the position of the chalazal vascular strand. The
seed is characterised by its large size and by its almost orbicular form: it
occurs as a detached specimen in beds containing Cordaites
(Noeggerathiopsis) and Glossopteris.
A species from Arkansas described by Lesquereux[1011] as Cardiocarpus
ingens [= Cordaicarpus ingens (Lesq.)] affords another example of a large
seed similar to C. indicus and, except in its more orbicular form, to
Samaropsis Leslii.
Samaropsis Milleri (Feistmantel).
Page 391
An examination of the type-specimen from the Calcutta
Museum enables me to amplify the original description in
an important particular. The species was found in Lower
Gondwana (Katharbari) beds in India and referred by
Feistmantel[1012] to the genus Carpolithes. Arber[1013], who
tentatively employed the generic name Cardiocarpus in
place of Carpolithes, suggests that the seeds may be
radiospermic, as Feistmantel’s drawings show only a very
narrow border to the nucule. The specimen reproduced in
fig. 504 was figured by Feistmantel without any
indication of a definite sarcotesta or wing, but as seen in
the drawing the ovate cordate sclerotesta is surrounded on Fig. 504.
one side and at the base by an outer envelope: this is Samaropsis
clearly seen at the apex where it shows a rounded Milleri.
termination sloping downwards towards the micropyle (Indian
precisely as in Samaropsis indica (Zeill.). The border is Geological
narrow at the sides and broader at the base as in S. Leslii. Survey,
The seed is 4·5 cm. long and 2·3 cm. broad, differing Calcutta; nat.
from S. indica in its rather smaller size and in the slightly size.)
narrower nucule. Though there is no decisive evidence as
to the parent-plant the occurrence of a specimen of this species partially
covered by a scale-leaf of a type[1014] very similar to that which is generally
recognised as belonging to Glossopteris suggests the possibility that the
seeds may belong to that genus. Scale-leaves of Glossopteris are described
in Volume ii., but it may be added here that leaves similar in form to those
from India, Australia, and elsewhere are figured by Geinitz[1015] from the
Altai Mountains as Trigonocarpus? actaeonelloides: the specimens are
represented with the basal scar at the apex.
Cordaicarpus. Geinitz.
In view of the fact that the generic names Cardiocarpus, Cordaicarpus,
and other designations have been applied to casts and impressions which
cannot be distinguished by any constant or important feature it is proposed
to adopt the name Cordaicarpus for platyspermic seeds, preserved as casts
or impressions, having a comparatively narrow border enclosing an ovate or
cordate-ovate nucule; the base is either rounded or cordate. The choice
Museum enables me to amplify the original description in
an important particular. The species was found in Lower
Gondwana (Katharbari) beds in India and referred by
Feistmantel[1012] to the genus Carpolithes. Arber[1013], who
tentatively employed the generic name Cardiocarpus in
place of Carpolithes, suggests that the seeds may be
radiospermic, as Feistmantel’s drawings show only a very
narrow border to the nucule. The specimen reproduced in
fig. 504 was figured by Feistmantel without any
indication of a definite sarcotesta or wing, but as seen in
the drawing the ovate cordate sclerotesta is surrounded on Fig. 504.
one side and at the base by an outer envelope: this is Samaropsis
clearly seen at the apex where it shows a rounded Milleri.
termination sloping downwards towards the micropyle (Indian
precisely as in Samaropsis indica (Zeill.). The border is Geological
narrow at the sides and broader at the base as in S. Leslii. Survey,
The seed is 4·5 cm. long and 2·3 cm. broad, differing Calcutta; nat.
from S. indica in its rather smaller size and in the slightly size.)
narrower nucule. Though there is no decisive evidence as
to the parent-plant the occurrence of a specimen of this species partially
covered by a scale-leaf of a type[1014] very similar to that which is generally
recognised as belonging to Glossopteris suggests the possibility that the
seeds may belong to that genus. Scale-leaves of Glossopteris are described
in Volume ii., but it may be added here that leaves similar in form to those
from India, Australia, and elsewhere are figured by Geinitz[1015] from the
Altai Mountains as Trigonocarpus? actaeonelloides: the specimens are
represented with the basal scar at the apex.
Cordaicarpus. Geinitz.
In view of the fact that the generic names Cardiocarpus, Cordaicarpus,
and other designations have been applied to casts and impressions which
cannot be distinguished by any constant or important feature it is proposed
to adopt the name Cordaicarpus for platyspermic seeds, preserved as casts
or impressions, having a comparatively narrow border enclosing an ovate or
cordate-ovate nucule; the base is either rounded or cordate. The choice
Page 392
between Cordaicarpus and Samaropsis depends on the breadth of the
border. Cordaicarpus, though more suggestive of a Cordaitean alliance,
may in some cases be a Pteridosperm seed.
Cordaicarpus Cordai (Geinitz). Lenticular seeds more or less orbicular or
broadly ovate (fig. 502, C, D), often slightly cordate at the base of the
nucule and with a broadly acute apex: the border is narrow or sometimes
hardly represented as in the seeds described by Berger as Rhabdocarpus
ovoides, a species similar to but more oval than Cordaicarpus Cordai. The
latter species[1016] occurs in several coalfields in Britain, France, Germany,
and elsewhere. Fig. 502, C, shows a good example from the Middle Coal
Measures of Yorkshire, 9 mm. long by 8 mm. broad; on the very slightly
cordate nucule are several faint ribs converging towards the base and apex
and between them fine striations, characters too indistinct to be reproduced
in the natural-size drawing. The flat border represents the sclerotesta. The
seed shown in fig. 502, D, from the Westphalian series of Warwickshire
belongs to the same species or is a closely allied type: the faint suggestion
of reticulation on its surface might be regarded as a reason for referring it to
C. areolatus Boul.[1017], a form characterised by a reticulation on the testa,
described by Zeiller[1018] and other authors. This reticulation is, however, in
some cases at least, formed by crumpling and splitting of the superficial
carbonised film into more or less regular meshes: the figured specimen
occurs with several other seeds of the same type, most of which have a
smooth surface. Dr Kidston tells me that a recent critical examination of
seeds in his collection leads him to regard some specimens (e.g. fig. 502, D)
previously referred by him to C. Cordai as identical with Carpolithes
membranaceus Goepp.[1019]
border. Cordaicarpus, though more suggestive of a Cordaitean alliance,
may in some cases be a Pteridosperm seed.
Cordaicarpus Cordai (Geinitz). Lenticular seeds more or less orbicular or
broadly ovate (fig. 502, C, D), often slightly cordate at the base of the
nucule and with a broadly acute apex: the border is narrow or sometimes
hardly represented as in the seeds described by Berger as Rhabdocarpus
ovoides, a species similar to but more oval than Cordaicarpus Cordai. The
latter species[1016] occurs in several coalfields in Britain, France, Germany,
and elsewhere. Fig. 502, C, shows a good example from the Middle Coal
Measures of Yorkshire, 9 mm. long by 8 mm. broad; on the very slightly
cordate nucule are several faint ribs converging towards the base and apex
and between them fine striations, characters too indistinct to be reproduced
in the natural-size drawing. The flat border represents the sclerotesta. The
seed shown in fig. 502, D, from the Westphalian series of Warwickshire
belongs to the same species or is a closely allied type: the faint suggestion
of reticulation on its surface might be regarded as a reason for referring it to
C. areolatus Boul.[1017], a form characterised by a reticulation on the testa,
described by Zeiller[1018] and other authors. This reticulation is, however, in
some cases at least, formed by crumpling and splitting of the superficial
carbonised film into more or less regular meshes: the figured specimen
occurs with several other seeds of the same type, most of which have a
smooth surface. Dr Kidston tells me that a recent critical examination of
seeds in his collection leads him to regard some specimens (e.g. fig. 502, D)
previously referred by him to C. Cordai as identical with Carpolithes
membranaceus Goepp.[1019]
Page 393
Fig. 505. Cordaicarpus Cordai. Cuticle of the testa. (Kidston Collection.)
The photograph reproduced in fig. 505 shows the result of chemically
treating the carbonised cuticle of a seed of Cordaicarpus Cordai, a method
little used as yet in the case of Palaeozoic plants but which may be useful in
distinguishing seeds which cannot be satisfactorily separated by
microscopic features. The superficial cells have very thick walls and present
an appearance similar to that of the sclerous cells in the testas of some
petrified specimens.
The larger seed shown in fig. 501, D, from Commentry, described by
Renault and Zeiller[1020] as Cardiocarpus sclerotesta, is another example of
Cordaicarpus as now defined.
IV. Miscellaneous Seeds.
In this section are included genera based on characters of comparatively
little morphological importance; their claim to treatment under a common
heading is that we know little or nothing of their anatomical features or of
the parent-plants.
i. Ribbed seeds.
The photograph reproduced in fig. 505 shows the result of chemically
treating the carbonised cuticle of a seed of Cordaicarpus Cordai, a method
little used as yet in the case of Palaeozoic plants but which may be useful in
distinguishing seeds which cannot be satisfactorily separated by
microscopic features. The superficial cells have very thick walls and present
an appearance similar to that of the sclerous cells in the testas of some
petrified specimens.
The larger seed shown in fig. 501, D, from Commentry, described by
Renault and Zeiller[1020] as Cardiocarpus sclerotesta, is another example of
Cordaicarpus as now defined.
IV. Miscellaneous Seeds.
In this section are included genera based on characters of comparatively
little morphological importance; their claim to treatment under a common
heading is that we know little or nothing of their anatomical features or of
the parent-plants.
i. Ribbed seeds.
Page 394
The seeds represented by the following genera possess ribs or flanges
usually in multiples of three; the transverse section may be triangular,
hexagonal, or polygonal. The symmetry is generally radial, but it is difficult
to determine whether a slight departure from the radiospermic form is an
original feature or the result of pressure. Some of the ribbed seeds with
which we are now concerned are no doubt closely allied to Trigonocarpus
and should be included in the Trigonocarpales, but others may well be
distinct forms.
Genera: Hexagonocarpus, Decagonocarpus, Polypterocarpus,
Rhynchogonium, Boroviczia, Diplopterotesta, Musocarpus, Holcospermum.
Hexagonocarpus. Renault.
This generic name is adopted by Renault[1021] for casts from Commentry
which, while probably identical with Brongniart’s Hexapterospermum,
afford no confirmatory anatomical evidence. The species Hexagonocarpus
crassus[1022] is represented by casts or nucules characterised by six well-
defined ribs and grooves with a length of nearly 3 cm. In this genus may be
included the cast from the Coal Measures of Lancashire described by
Williamson[1023] as Hexapterospermum Noeggerathi (fig. 506, H), and
another British example is afforded by Hexagonocarpus Hookeri Kidst.[1024],
a rare fossil in the South Staffordshire coalfield. It is impossible confidently
to assign these ribbed casts to genera founded on petrified specimens as
they almost certainly belong to different types, but the employment of the
name Hexagonocarpus may conveniently be used for casts or impressions
of seeds with six longitudinal ribs differing in their relatively broader and
less prominent form from the wing-like flanges of Polypterocarpus (cf. fig.
496, B). The seeds described by Dr P. Bertrand[1025] as Hexapterospermum
modestae, and believed by him to belong to a plant with Neuropteris fronds,
should be included in Hexagonocarpus as we have no definite knowledge
of their anatomical features.
Decagonocarpus. Renault.
This name, proposed by Renault[1026], is applied to seeds without petrified
tissues characterised by ten ribs; an example is afforded by
Decagonocarpus olivaeformis from the Commentry coalfield, an elliptical
usually in multiples of three; the transverse section may be triangular,
hexagonal, or polygonal. The symmetry is generally radial, but it is difficult
to determine whether a slight departure from the radiospermic form is an
original feature or the result of pressure. Some of the ribbed seeds with
which we are now concerned are no doubt closely allied to Trigonocarpus
and should be included in the Trigonocarpales, but others may well be
distinct forms.
Genera: Hexagonocarpus, Decagonocarpus, Polypterocarpus,
Rhynchogonium, Boroviczia, Diplopterotesta, Musocarpus, Holcospermum.
Hexagonocarpus. Renault.
This generic name is adopted by Renault[1021] for casts from Commentry
which, while probably identical with Brongniart’s Hexapterospermum,
afford no confirmatory anatomical evidence. The species Hexagonocarpus
crassus[1022] is represented by casts or nucules characterised by six well-
defined ribs and grooves with a length of nearly 3 cm. In this genus may be
included the cast from the Coal Measures of Lancashire described by
Williamson[1023] as Hexapterospermum Noeggerathi (fig. 506, H), and
another British example is afforded by Hexagonocarpus Hookeri Kidst.[1024],
a rare fossil in the South Staffordshire coalfield. It is impossible confidently
to assign these ribbed casts to genera founded on petrified specimens as
they almost certainly belong to different types, but the employment of the
name Hexagonocarpus may conveniently be used for casts or impressions
of seeds with six longitudinal ribs differing in their relatively broader and
less prominent form from the wing-like flanges of Polypterocarpus (cf. fig.
496, B). The seeds described by Dr P. Bertrand[1025] as Hexapterospermum
modestae, and believed by him to belong to a plant with Neuropteris fronds,
should be included in Hexagonocarpus as we have no definite knowledge
of their anatomical features.
Decagonocarpus. Renault.
This name, proposed by Renault[1026], is applied to seeds without petrified
tissues characterised by ten ribs; an example is afforded by
Decagonocarpus olivaeformis from the Commentry coalfield, an elliptical
Page 395
seed which bears a close resemblance to Holcospermum sulcatum (fig. 506,
A) except in the smaller number of ribs.
Polypterocarpus. Grand’Eury.
Grand’Eury[1027] adopted this generic name for seeds from St Étienne
characterised by the presence of three, six, or more deep wings or flanges.
The term Pterospermum has recently been proposed by Arber[1028] for a seed
from the Coal Measures of Staffordshire, which he names P. anglicum: the
type-species of the genus has three deep wings, one from each angle. For
the same seed Kidston[1029] proposed the name Tripterospermum ellipticum,
but as Arber’s account was published first his specific name has priority.
Pterospermum had, however, been previously used for a genus of
Sterculiaceae, and partly on this account but mainly because Grand’Eury’s
genus Polypterocarpus is available the latter designation is adopted. In
Polypterocarpus anglicus (fig. 496, B) the flanges project slightly beyond
the apex of the seed and there is a small notch at the base; the nucule is 5
cm. long and 1 cm. broad. While it is not improbable that this seed is
generically identical with Brongniart’s Tripterospermum[1030], it is safer, in
the absence of structural details, to employ the less committal term. There is
no information with regard to the nature of the parent-plants of species of
Polypterocarpus. The English seed from the Middle Coal Measures of
Derbyshire and the Staffordshire coalfield described by Arber[1031] as
Radiospermum ornatum and by Kidston[1032] as Polypterospermum ornatum
affords another example of Polypterocarpus as the generic name is here
employed.
Rhynchogonium. Heer.
Heer[1033] proposed this generic name for some globose, ovate, or oblong
‘fruits’ from Lower Carboniferous strata in Spitzbergen, including also
fragments of ‘leaves’ which without satisfactory evidence he believed to
belong to the same plant. The supposed fruits are clearly seeds, and
Nathorst regards the ‘leaves’ as portions of a Fern rachis. Heer described
four species, but these have since been reduced to two, and indeed it is
probable that only one type, Rhynchogonium costatum, is represented.
Nathorst[1034] compares Heer’s seeds with a Lower Carboniferous species
A) except in the smaller number of ribs.
Polypterocarpus. Grand’Eury.
Grand’Eury[1027] adopted this generic name for seeds from St Étienne
characterised by the presence of three, six, or more deep wings or flanges.
The term Pterospermum has recently been proposed by Arber[1028] for a seed
from the Coal Measures of Staffordshire, which he names P. anglicum: the
type-species of the genus has three deep wings, one from each angle. For
the same seed Kidston[1029] proposed the name Tripterospermum ellipticum,
but as Arber’s account was published first his specific name has priority.
Pterospermum had, however, been previously used for a genus of
Sterculiaceae, and partly on this account but mainly because Grand’Eury’s
genus Polypterocarpus is available the latter designation is adopted. In
Polypterocarpus anglicus (fig. 496, B) the flanges project slightly beyond
the apex of the seed and there is a small notch at the base; the nucule is 5
cm. long and 1 cm. broad. While it is not improbable that this seed is
generically identical with Brongniart’s Tripterospermum[1030], it is safer, in
the absence of structural details, to employ the less committal term. There is
no information with regard to the nature of the parent-plants of species of
Polypterocarpus. The English seed from the Middle Coal Measures of
Derbyshire and the Staffordshire coalfield described by Arber[1031] as
Radiospermum ornatum and by Kidston[1032] as Polypterospermum ornatum
affords another example of Polypterocarpus as the generic name is here
employed.
Rhynchogonium. Heer.
Heer[1033] proposed this generic name for some globose, ovate, or oblong
‘fruits’ from Lower Carboniferous strata in Spitzbergen, including also
fragments of ‘leaves’ which without satisfactory evidence he believed to
belong to the same plant. The supposed fruits are clearly seeds, and
Nathorst regards the ‘leaves’ as portions of a Fern rachis. Heer described
four species, but these have since been reduced to two, and indeed it is
probable that only one type, Rhynchogonium costatum, is represented.
Nathorst[1034] compares Heer’s seeds with a Lower Carboniferous species
Page 396
described by Young[1035] as Trigonocarpum gloagianum, the resemblance of
which to the Spitzbergen seeds was pointed out by Kidston. A seed of
Rhynchogonium costatum is about the size of a hazel-nut and may reach a
length of 21 mm.; it is ovate, with a broad rounded base, and in the upper
third is tapered and conical, the sides of the characteristic snout being
distinguished from the smooth surface of the rest of the seed by the
presence of eight ribs converging towards the apex (506, G). Zalessky[1036]
recorded closely allied seeds from Lower Carboniferous beds in Northern
Russia, assigning them to a new genus Boroviczia, the type-species being B.
Karpinskii; he adduced arguments in favour of Heer’s interpretation of the
fossils as fruits but, according to Nathorst, this view has been abandoned. In
his recent memoir on the Culm flora of Spitzbergen Nathorst[1037] discusses
the morphological nature of Rhynchogonium seeds and describes additional
specimens. Without the aid of petrified examples it is hardly possible to
determine the true nature of the fossils.
which to the Spitzbergen seeds was pointed out by Kidston. A seed of
Rhynchogonium costatum is about the size of a hazel-nut and may reach a
length of 21 mm.; it is ovate, with a broad rounded base, and in the upper
third is tapered and conical, the sides of the characteristic snout being
distinguished from the smooth surface of the rest of the seed by the
presence of eight ribs converging towards the apex (506, G). Zalessky[1036]
recorded closely allied seeds from Lower Carboniferous beds in Northern
Russia, assigning them to a new genus Boroviczia, the type-species being B.
Karpinskii; he adduced arguments in favour of Heer’s interpretation of the
fossils as fruits but, according to Nathorst, this view has been abandoned. In
his recent memoir on the Culm flora of Spitzbergen Nathorst[1037] discusses
the morphological nature of Rhynchogonium seeds and describes additional
specimens. Without the aid of petrified examples it is hardly possible to
determine the true nature of the fossils.
Page 397
Fig. 506. A, Holcospermum sulcatum. B, C, Codonospermum anomalum.
D, Diplopterotesta spitzbergensis (× 3). E, Gnetopsis elliptica
(cupule). F, Thysanotesta sagittula. G, Rhynchogonium costatum. H,
Hexagonocarpus Noeggerathi. I, Boroviczia Karpinskii. K,
Rhabdospermum tunicatum. (A, Kidston Collection; B, after
Grand’Eury; C, after Renault and Zeiller; D, F, G, after Nathorst;
E, after Renault; H, after Williamson; I, after Zalessky; K, after
Berger.)
Some specimens of Rhynchogonium sulcatum in Dr Kidston’s collection
show the original surface-features: the carbonised integument is divided in
the upper region into linear lobes separated from one another at their origin
by fairly wide sinuses, a type of integument suggesting comparison with
Physostoma. This species was originally described by Lindley and Hutton
as Carpolithes sulcata[1038] from Lower Carboniferous rocks at Newhaven in
Scotland and has recently been figured by Zalessky[1039] from specimens in
D, Diplopterotesta spitzbergensis (× 3). E, Gnetopsis elliptica
(cupule). F, Thysanotesta sagittula. G, Rhynchogonium costatum. H,
Hexagonocarpus Noeggerathi. I, Boroviczia Karpinskii. K,
Rhabdospermum tunicatum. (A, Kidston Collection; B, after
Grand’Eury; C, after Renault and Zeiller; D, F, G, after Nathorst;
E, after Renault; H, after Williamson; I, after Zalessky; K, after
Berger.)
Some specimens of Rhynchogonium sulcatum in Dr Kidston’s collection
show the original surface-features: the carbonised integument is divided in
the upper region into linear lobes separated from one another at their origin
by fairly wide sinuses, a type of integument suggesting comparison with
Physostoma. This species was originally described by Lindley and Hutton
as Carpolithes sulcata[1038] from Lower Carboniferous rocks at Newhaven in
Scotland and has recently been figured by Zalessky[1039] from specimens in
Page 398
the Kidston collection from the Lower Calciferous sandstone of Midlothian.
Nothing definite can be said as to the parent-plant, but it is significant that
in Midlothian Rhynchogonium sulcatum occurs in a bed full of isolated
pinnules of a Cardiopteris almost to the exclusion of any other fossils[1040].
The seed figured by Nathorst[1041] from the Culm of Spitzbergen as
Lagenospermum? glandiforme agrees closely with Rhynchogonium and
Boroviczia, and it is impossible to decide whether the lobed appearance is
due to the presence of a cupule or to the divisions of an integument.
Boroviczia. Zalessky.
The specimens from Lower Carboniferous beds in Russia[1042] on which
this genus was founded are perhaps unnecessarily separated from
Rhynchogonium; they are ovate and beaked, 10 mm. long with a maximum
breadth of 6 mm. The type-species, Boroviczia Karpinskii (fig. 506, I), is
represented both by specimens in which the cast is complete and by others
in which the apical snout of the integument is split into separate lobes
identical in form and apparently in number with those of Rhynchogonium.
Nathorst[1043], who retains the generic name and describes two additional
species from Spitzbergen, points out that in Boroviczia the tapered apex is
more sharply differentiated from the broader basal portion, a difference
hardly worthy of generic recognition. If Boroviczia is retained as a genus
distinct from Rhynchogonium it should include the seeds described by
Young as Trigonocarpum gloagianum.
Diplopterotesta. Nathorst.
Diplopterotesta spitzbergensis (Heer). Heer[1044] included in Samaropsis
some seeds, described as Samaropsis spitzbergensis, from Lower
Carboniferous strata in Spitzbergen which differ considerably from typical
examples of the genus. These have recently been made the type of a new
genus Diplopterotesta[1045]: they are platyspermic seeds nearly twice as long
as broad, 6–9 × 3·5–5 mm., characterised by a thin sclerotesta expanded
throughout the length of the seed into two prominent transversely striated
wing-like ribs or flanges (fig. 506, D). At the apex, which is broad in
contrast to the pointed basal end of the seed, the sclerotesta forms a crown
of eight lobes about the flat summit of the seed-body. As Nathorst points
Nothing definite can be said as to the parent-plant, but it is significant that
in Midlothian Rhynchogonium sulcatum occurs in a bed full of isolated
pinnules of a Cardiopteris almost to the exclusion of any other fossils[1040].
The seed figured by Nathorst[1041] from the Culm of Spitzbergen as
Lagenospermum? glandiforme agrees closely with Rhynchogonium and
Boroviczia, and it is impossible to decide whether the lobed appearance is
due to the presence of a cupule or to the divisions of an integument.
Boroviczia. Zalessky.
The specimens from Lower Carboniferous beds in Russia[1042] on which
this genus was founded are perhaps unnecessarily separated from
Rhynchogonium; they are ovate and beaked, 10 mm. long with a maximum
breadth of 6 mm. The type-species, Boroviczia Karpinskii (fig. 506, I), is
represented both by specimens in which the cast is complete and by others
in which the apical snout of the integument is split into separate lobes
identical in form and apparently in number with those of Rhynchogonium.
Nathorst[1043], who retains the generic name and describes two additional
species from Spitzbergen, points out that in Boroviczia the tapered apex is
more sharply differentiated from the broader basal portion, a difference
hardly worthy of generic recognition. If Boroviczia is retained as a genus
distinct from Rhynchogonium it should include the seeds described by
Young as Trigonocarpum gloagianum.
Diplopterotesta. Nathorst.
Diplopterotesta spitzbergensis (Heer). Heer[1044] included in Samaropsis
some seeds, described as Samaropsis spitzbergensis, from Lower
Carboniferous strata in Spitzbergen which differ considerably from typical
examples of the genus. These have recently been made the type of a new
genus Diplopterotesta[1045]: they are platyspermic seeds nearly twice as long
as broad, 6–9 × 3·5–5 mm., characterised by a thin sclerotesta expanded
throughout the length of the seed into two prominent transversely striated
wing-like ribs or flanges (fig. 506, D). At the apex, which is broad in
contrast to the pointed basal end of the seed, the sclerotesta forms a crown
of eight lobes about the flat summit of the seed-body. As Nathorst points
Page 399
out, this species closely resembles the Carboniferous seeds figured by
Grand’Eury[1046] as Polypterocarpus, but in the latter type there are more
than two wings. Nathorst’s figures, one of which is reproduced in fig. 506,
D, suggest a difficulty in determining the number of the flanges, which
would seem to be more than two, but this appearance is regarded by
Nathorst as misleading and he believes that except at the apex there are only
two wings.
Musocarpus. Brongniart.
Brongniart[1047] proposed this name for two species, M. prismaticus and
M. difformis, from French Coal Measures, but gave no description of the
specimens. The type-species, described from the Loire by Grand’Eury as
Musocarpus prismaticus[1048], is an ovate seed nearly 3 cm. long with six
longitudinal ribs, three being more prominent than the others, and
characterised by a ribbed prolongation of the base of uniform diameter
spoken of as a carpophore, which was apparently articulated to the lower
part of the seed-proper from which it was easily detached by a natural
absciss-layer. Nothing is known of the structure or of the affinity of the
genus. Some specimens in Dr Kidston’s collection from Westphalian beds
in Lanarkshire are closely allied to or perhaps identical with M. prismaticus.
In the presence of a distinct basal region Musocarpus resembles
Codonospermum[1049], though without any knowledge of the anatomy of the
former type it is impossible to say whether or not this resemblance has any
morphological importance.
Holcospermum. Nathorst.
Holcospermum sulcatum (Sternberg). The cast reproduced in fig. 506, A,
affords a good example of a form of seed recorded under several generic
names and not uncommon in Upper Palaeozoic rocks in Europe and North
America, which in most cases cannot be assigned to a genus implying the
possession of certain anatomical characters. This type was figured by
Sternberg[1050] from the Coal Measures of Radnitz as Carpolites sulcatus.
Some ‘fruits’ collected on the beach near Newhaven, Midlothian, from the
Calciferous Sandstone series, are figured by Lindley and Hutton[1051] as
Carpolithes sulcata, but as already stated these have been transferred[1052] to
Grand’Eury[1046] as Polypterocarpus, but in the latter type there are more
than two wings. Nathorst’s figures, one of which is reproduced in fig. 506,
D, suggest a difficulty in determining the number of the flanges, which
would seem to be more than two, but this appearance is regarded by
Nathorst as misleading and he believes that except at the apex there are only
two wings.
Musocarpus. Brongniart.
Brongniart[1047] proposed this name for two species, M. prismaticus and
M. difformis, from French Coal Measures, but gave no description of the
specimens. The type-species, described from the Loire by Grand’Eury as
Musocarpus prismaticus[1048], is an ovate seed nearly 3 cm. long with six
longitudinal ribs, three being more prominent than the others, and
characterised by a ribbed prolongation of the base of uniform diameter
spoken of as a carpophore, which was apparently articulated to the lower
part of the seed-proper from which it was easily detached by a natural
absciss-layer. Nothing is known of the structure or of the affinity of the
genus. Some specimens in Dr Kidston’s collection from Westphalian beds
in Lanarkshire are closely allied to or perhaps identical with M. prismaticus.
In the presence of a distinct basal region Musocarpus resembles
Codonospermum[1049], though without any knowledge of the anatomy of the
former type it is impossible to say whether or not this resemblance has any
morphological importance.
Holcospermum. Nathorst.
Holcospermum sulcatum (Sternberg). The cast reproduced in fig. 506, A,
affords a good example of a form of seed recorded under several generic
names and not uncommon in Upper Palaeozoic rocks in Europe and North
America, which in most cases cannot be assigned to a genus implying the
possession of certain anatomical characters. This type was figured by
Sternberg[1050] from the Coal Measures of Radnitz as Carpolites sulcatus.
Some ‘fruits’ collected on the beach near Newhaven, Midlothian, from the
Calciferous Sandstone series, are figured by Lindley and Hutton[1051] as
Carpolithes sulcata, but as already stated these have been transferred[1052] to
Page 400
the genus Rhynchogonium. Several authors have referred specimens of the
type now included in Holcospermum to Rhabdocarpus, but that genus, as
stated on a previous page, is restricted to seeds agreeing in form with R.
tunicatus. Renault[1053] instituted the genus Colpospermum for a partially
petrified seed from Commentry agreeing externally with Carpolites
sulcatus Sternb. and regarded by him as specifically identical, characterised
by longitudinal ribs which represent folds of the testa, the intervening
grooves being occupied by an irregular reticulum formed by occasionally
anastomosing smaller ribs. The generic name Colpospermum should
therefore be reserved for ribbed seeds showing the anatomical features
described by Renault and Zeiller: its application to Sternberg’s species is
inadvisable on the ground that we have no information with regard to the
morphological nature of the ribbing. More recently Arber[1054] has proposed
the name Platyspermum, a name previously applied to a Cruciferous plant,
for Stephanian and Permian seeds formerly assigned to Berger’s genus
Rhabdocarpus, which are symmetrical in two planes. In this genus he
includes Platyspermum sulcatum and among other species P. Kidstoni
founded on a seed originally identified by Kidston[1055] as Rhabdocarpus
multistriatus Sternb. which, though probably a distinct species, is of the
same general type as C. sulcatus Sternb.
The cast represented in fig. 506, A, from the Middle Coal Measures of
Yorkshire is 3·5 cm. long and has 18 regular longitudinal ribs: it is radially
symmetrical and does not conform in this respect to Arber’s definition of
Platyspermum. In many cases, e.g. the flattened seed figured by Kidston as
Rhabdocarpus multistriatus, it is impossible to determine the symmetry of
the seed. The old generic name Carpolites, Carpolithes or Carpolithus has
been used in a very wide sense and does not connote any well-defined
features; it should be reserved, in the form Carpolithus as used by
Linnaeus, for seeds that cannot be assigned to a systematic position or
which do not exhibit any distinctive characters worthy of emphasis by the
institution of a special name. The generic term Holcospermum, recently
proposed by Nathorst[1056], is a suitable name for this type of seed; as
defined by the author, it includes seeds that may be radiospermic or
platyspermic. Specimens of the type-species, H. dubium[1057],from the
Lower Carboniferous beds of Spitzbergen, agree closely in size and shape
with some examples of Rhynchogonium and Boroviczia, but they are
distinguished by prominent ribs extending the whole length of the cast. In
type now included in Holcospermum to Rhabdocarpus, but that genus, as
stated on a previous page, is restricted to seeds agreeing in form with R.
tunicatus. Renault[1053] instituted the genus Colpospermum for a partially
petrified seed from Commentry agreeing externally with Carpolites
sulcatus Sternb. and regarded by him as specifically identical, characterised
by longitudinal ribs which represent folds of the testa, the intervening
grooves being occupied by an irregular reticulum formed by occasionally
anastomosing smaller ribs. The generic name Colpospermum should
therefore be reserved for ribbed seeds showing the anatomical features
described by Renault and Zeiller: its application to Sternberg’s species is
inadvisable on the ground that we have no information with regard to the
morphological nature of the ribbing. More recently Arber[1054] has proposed
the name Platyspermum, a name previously applied to a Cruciferous plant,
for Stephanian and Permian seeds formerly assigned to Berger’s genus
Rhabdocarpus, which are symmetrical in two planes. In this genus he
includes Platyspermum sulcatum and among other species P. Kidstoni
founded on a seed originally identified by Kidston[1055] as Rhabdocarpus
multistriatus Sternb. which, though probably a distinct species, is of the
same general type as C. sulcatus Sternb.
The cast represented in fig. 506, A, from the Middle Coal Measures of
Yorkshire is 3·5 cm. long and has 18 regular longitudinal ribs: it is radially
symmetrical and does not conform in this respect to Arber’s definition of
Platyspermum. In many cases, e.g. the flattened seed figured by Kidston as
Rhabdocarpus multistriatus, it is impossible to determine the symmetry of
the seed. The old generic name Carpolites, Carpolithes or Carpolithus has
been used in a very wide sense and does not connote any well-defined
features; it should be reserved, in the form Carpolithus as used by
Linnaeus, for seeds that cannot be assigned to a systematic position or
which do not exhibit any distinctive characters worthy of emphasis by the
institution of a special name. The generic term Holcospermum, recently
proposed by Nathorst[1056], is a suitable name for this type of seed; as
defined by the author, it includes seeds that may be radiospermic or
platyspermic. Specimens of the type-species, H. dubium[1057],from the
Lower Carboniferous beds of Spitzbergen, agree closely in size and shape
with some examples of Rhynchogonium and Boroviczia, but they are
distinguished by prominent ribs extending the whole length of the cast. In
Page 401
some seeds similar to H. sulcatum the ribs form sharp ridges, but the
difference between rounded and sharp ridges is often determined by the
method of preservation: a specimen deprived of its outer flesh would form a
cast more sharply ribbed than a seed in which the sarcotesta had been
moulded on to the ribbed sclerotesta. On the other hand some ribs are
formed by blunt sclerotestal folds as in Colpospermum: both types of
ribbing are included in the genus Holcospermum.
ii. Other Genera.
Malacotesta. Williamson.
This generic name was instituted by Williamson[1058] for a petrified seed
from the Coal Measures of Lancashire which he named Malacotesta
oblonga: the type-specimen is a small seed 6–7 mm. long characterised by a
thick fleshy integument. The structure is however insufficiently known to
admit of a satisfactory comparison of the imperfectly preserved specimen
figured by Williamson with other types.
Thysanotesta. Nathorst.
Nathorst[1059] founded this genus on a single seed from the Lower
Carboniferous plant-beds of Spitzbergen which exhibits features
sufficiently distinctive to justify its recognition as the type of a separate
genus.
Thysanotesta sagittula Nathorst. The type-specimen is a long and narrow
seed, 20 mm. long, ovate below and prolonged apically into a slender beak,
8 mm. in length, which probably represents a micropylar tube; the beak
bears numerous stiff hairs (fig. 506, F). The seed closely resembles a carpel
of Erodium without the horizontal part of the awn. There is no evidence as
to the nature of the parent-plant but the species affords an interesting
example of a Palaeozoic seed apparently adapted for wind-dispersal, or
possibly the bristles may have served the same purpose as in the fruits of
Erodium. Attention is called elsewhere[1060] to the frequent resemblance of
Palaeozoic seeds such as Thysanotesta to fruits of recent flowering plants.
difference between rounded and sharp ridges is often determined by the
method of preservation: a specimen deprived of its outer flesh would form a
cast more sharply ribbed than a seed in which the sarcotesta had been
moulded on to the ribbed sclerotesta. On the other hand some ribs are
formed by blunt sclerotestal folds as in Colpospermum: both types of
ribbing are included in the genus Holcospermum.
ii. Other Genera.
Malacotesta. Williamson.
This generic name was instituted by Williamson[1058] for a petrified seed
from the Coal Measures of Lancashire which he named Malacotesta
oblonga: the type-specimen is a small seed 6–7 mm. long characterised by a
thick fleshy integument. The structure is however insufficiently known to
admit of a satisfactory comparison of the imperfectly preserved specimen
figured by Williamson with other types.
Thysanotesta. Nathorst.
Nathorst[1059] founded this genus on a single seed from the Lower
Carboniferous plant-beds of Spitzbergen which exhibits features
sufficiently distinctive to justify its recognition as the type of a separate
genus.
Thysanotesta sagittula Nathorst. The type-specimen is a long and narrow
seed, 20 mm. long, ovate below and prolonged apically into a slender beak,
8 mm. in length, which probably represents a micropylar tube; the beak
bears numerous stiff hairs (fig. 506, F). The seed closely resembles a carpel
of Erodium without the horizontal part of the awn. There is no evidence as
to the nature of the parent-plant but the species affords an interesting
example of a Palaeozoic seed apparently adapted for wind-dispersal, or
possibly the bristles may have served the same purpose as in the fruits of
Erodium. Attention is called elsewhere[1060] to the frequent resemblance of
Palaeozoic seeds such as Thysanotesta to fruits of recent flowering plants.
Page 402
Carpolithus. Linnaeus.
Nathorst[1061] has pointed out that this generic name was employed by
Linnaeus for fossil fruits: in the form Carpolites (Sternberg) or
Carpolithes[1062] it has been widely used and differently defined by authors,
usually in a comprehensive sense including fossil seeds from both
Palaeozoic and Mesozoic strata which cannot be assigned to a definite
position in the plant-kingdom. It is desirable to adopt some designation for
seeds from strata of different ages which do not exhibit any features
sufficiently distinctive to justify the creation of a special genus. By
employing such a name as Carpolithus, without attempting to define its
characters within prescribed limits, for casts or impressions of seeds which
are not distinguished by any striking characters and cannot be allocated to
any particular section of seed-bearing plants the unnecessary multiplication
of generic titles is avoided: when any additional data are obtained
differentiating particular types from other forms of Carpolithus the
provisional term should be superseded by some distinctive generic name.
Among seeds from the Coal Measures there are several examples of both
large and small types without any regular ribs or lacking such features as
serve to distinguish the genera already described, which are appropriately
included in Carpolithus. The two species Carpolithus Wildii Kidst.[1063] and
C. bivalvis Goepp.[1064] are two examples of seeds from Upper
Carboniferous rocks which it is desirable to refer to this comprehensive
genus pending further discoveries as to their morphological features. The
Jurassic species C. conicus Lind. and Hutt.[1065] is another type which it has
been customary to include in Carpolithus.
(Microspermum. Arber.)
The generic name Microspermum has recently been proposed by
Arber[1066] for some Westphalian seeds described by Carpentier[1067] from the
North of France as Carpolithes? samaroides and for similar fossils from the
Middle Coal Measures of Nottingham. The supposed seeds are small, ovate
or pyriform bodies, 5–12 mm. long and 2·5–6 mm. broad, with one
extremity broadly rounded and the other acute: one side is keeled, the other
grooved, and a large foramen occurs near the broader end and on the
grooved surface. Arber emphasises the fact that the specimens are
symmetrical in one plane only. As the author of the genus points out the
Nathorst[1061] has pointed out that this generic name was employed by
Linnaeus for fossil fruits: in the form Carpolites (Sternberg) or
Carpolithes[1062] it has been widely used and differently defined by authors,
usually in a comprehensive sense including fossil seeds from both
Palaeozoic and Mesozoic strata which cannot be assigned to a definite
position in the plant-kingdom. It is desirable to adopt some designation for
seeds from strata of different ages which do not exhibit any features
sufficiently distinctive to justify the creation of a special genus. By
employing such a name as Carpolithus, without attempting to define its
characters within prescribed limits, for casts or impressions of seeds which
are not distinguished by any striking characters and cannot be allocated to
any particular section of seed-bearing plants the unnecessary multiplication
of generic titles is avoided: when any additional data are obtained
differentiating particular types from other forms of Carpolithus the
provisional term should be superseded by some distinctive generic name.
Among seeds from the Coal Measures there are several examples of both
large and small types without any regular ribs or lacking such features as
serve to distinguish the genera already described, which are appropriately
included in Carpolithus. The two species Carpolithus Wildii Kidst.[1063] and
C. bivalvis Goepp.[1064] are two examples of seeds from Upper
Carboniferous rocks which it is desirable to refer to this comprehensive
genus pending further discoveries as to their morphological features. The
Jurassic species C. conicus Lind. and Hutt.[1065] is another type which it has
been customary to include in Carpolithus.
(Microspermum. Arber.)
The generic name Microspermum has recently been proposed by
Arber[1066] for some Westphalian seeds described by Carpentier[1067] from the
North of France as Carpolithes? samaroides and for similar fossils from the
Middle Coal Measures of Nottingham. The supposed seeds are small, ovate
or pyriform bodies, 5–12 mm. long and 2·5–6 mm. broad, with one
extremity broadly rounded and the other acute: one side is keeled, the other
grooved, and a large foramen occurs near the broader end and on the
grooved surface. Arber emphasises the fact that the specimens are
symmetrical in one plane only. As the author of the genus points out the
Page 403
morphological nature of the fossils is not thoroughly established, nor is the
parent-plant known. In view of the ill-defined characters of the specimens
so far discovered it is hardly desirable to institute a new generic name
implying their seed-nature; moreover Microspermum has previously been
employed for a genus of Compositae. An examination of specimens leads
me to doubt their seed-nature and it would seem more likely that they are
foliar organs, possibly bracts which originally bore seeds or sporangia.
An examination of some of the specimens of supposed Permian seeds for
which Geinitz[1068] proposed the generic name Guilelmites convinced me
that they are inorganic structures, probably nodules in shale smoothed and
rounded by slickensiding.
parent-plant known. In view of the ill-defined characters of the specimens
so far discovered it is hardly desirable to institute a new generic name
implying their seed-nature; moreover Microspermum has previously been
employed for a genus of Compositae. An examination of specimens leads
me to doubt their seed-nature and it would seem more likely that they are
foliar organs, possibly bracts which originally bore seeds or sporangia.
An examination of some of the specimens of supposed Permian seeds for
which Geinitz[1068] proposed the generic name Guilelmites convinced me
that they are inorganic structures, probably nodules in shale smoothed and
rounded by slickensiding.
Page 404
Page 405
CHAPTER XXXVI.
CYCADOPHYTA.
The term Cycadophyta, suggested by Nathorst[1069], is used in a
comprehensive sense to include both recent Cycads and the much larger
number of extinct types which it is customary to speak of as Cycadean
plants or fossil Cycads. The designation ‘Cycads’ in the case of the majority
of the fossil forms is, however, open to criticism on the ground that they
differ too widely from existing genera to be associated with them in one
class. It would be pedantic and inconvenient to give up the almost universal
practice of extending the term Cycad beyond the limits defined by the
characters of recent species. The important point is to adopt some
classification which gives expression to our views as to the degree of
affinity between recent and extinct types. In a considerable number of
cases, especially impressions of presumably Cycadean fronds and stems
that occur without any fertile shoots, it is impossible to determine the
degree of relationship to modern types. It was with a view to a rational
group-designation for such fossils that Nathorst proposed the term
Cycadophyta, including in it the two classes Cycadales and Bennettitales.
The Cycadales comprise the recent genera and such extinct types as may
legitimately be included in the same class, but as we shall see later there are
hardly any fossil species that can be assigned to this section on thoroughly
satisfactory grounds. The term Bennettitales is used by Engler, Nathorst,
and several other authors as a class-designation for a large number of
Mesozoic Cycads agreeing in their more important morphological
characters with the Lower Cretaceous stems on which Carruthers[1070]
founded the genus Bennettites, placing it in a new tribe, the Bennettiteae.
Some authors have followed Carruthers in the use of the family-name
Bennettiteae for a subdivision of the Cycadales equal in rank to the
Cycadaceae, while others, wishing to give greater emphasis to the
difference between the extinct and recent plants, prefer to adopt the class-
name Bennettitales. Carruthers regarded Bennettites as occupying the same
position in relation to other Cycads as Taxus holds with regard to the cone-
bearing members of the Coniferae. The adoption of Bennettitales is
CYCADOPHYTA.
The term Cycadophyta, suggested by Nathorst[1069], is used in a
comprehensive sense to include both recent Cycads and the much larger
number of extinct types which it is customary to speak of as Cycadean
plants or fossil Cycads. The designation ‘Cycads’ in the case of the majority
of the fossil forms is, however, open to criticism on the ground that they
differ too widely from existing genera to be associated with them in one
class. It would be pedantic and inconvenient to give up the almost universal
practice of extending the term Cycad beyond the limits defined by the
characters of recent species. The important point is to adopt some
classification which gives expression to our views as to the degree of
affinity between recent and extinct types. In a considerable number of
cases, especially impressions of presumably Cycadean fronds and stems
that occur without any fertile shoots, it is impossible to determine the
degree of relationship to modern types. It was with a view to a rational
group-designation for such fossils that Nathorst proposed the term
Cycadophyta, including in it the two classes Cycadales and Bennettitales.
The Cycadales comprise the recent genera and such extinct types as may
legitimately be included in the same class, but as we shall see later there are
hardly any fossil species that can be assigned to this section on thoroughly
satisfactory grounds. The term Bennettitales is used by Engler, Nathorst,
and several other authors as a class-designation for a large number of
Mesozoic Cycads agreeing in their more important morphological
characters with the Lower Cretaceous stems on which Carruthers[1070]
founded the genus Bennettites, placing it in a new tribe, the Bennettiteae.
Some authors have followed Carruthers in the use of the family-name
Bennettiteae for a subdivision of the Cycadales equal in rank to the
Cycadaceae, while others, wishing to give greater emphasis to the
difference between the extinct and recent plants, prefer to adopt the class-
name Bennettitales. Carruthers regarded Bennettites as occupying the same
position in relation to other Cycads as Taxus holds with regard to the cone-
bearing members of the Coniferae. The adoption of Bennettitales is
Page 406
intended to convey the impression that the class is more distantly related to
the recent Cycads than is implied by the analogy of Taxus. Nathorst[1071], as
the result of his discovery of certain reproductive organs associated with
some Rhaetic fronds described as Dioonites spectabilis, proposed a third
subdivision, the Dioonitales, but he subsequently[1072] restored the fronds to
their original designation Nilssonia pterophylloides, and on further
examination found that the supposed microspore-bearing organs were
seeds. Nilssonia pterophylloides would therefore find a more natural place
in the class Nilssoniales instituted by Thomas[1073].
BENNETTITALES.
Cycadeoidea. Buckland.
In 1827 Buckland[1074] proposed the generic name Cycadeoidea for some
petrified stems from the Purbeck beds in the Isle of Portland and published
a description of two species, Cycadeoidea megalophylla and C.
microphylla. Brongniart[1075] considered Buckland’s term Cycadeoidea
inappropriate and proposed in its place Mantellia, the type-species being
Mantellia nidiformis Brongn., the Portland stem which Buckland a month
or two later called independently Cycadeoidea megalophylla. Subsequently
Brongniart[1076] withdrew Mantellia as it had been previously used by
Parkinson for a sponge and substituted Cycadites. Some years later
Carruthers[1077] revived Mantellia for a type of Cycadean stem from Portland
though one species, apparently indistinguishable from those referred to
Mantellia, he named Bennettites portlandicus. There is no adequate reason
for the retention of the generic name Mantellia. The close resemblance of
the short and thick stems (12–30 cm. in height) described by Buckland to
those of some recent Cycads was recognised by Robert Brown and
Loddiges and the former suggested to Buckland the inclusion of the fossils
in a new family Cycadeoideae. It was this suggestion that led Buckland to
adopt Cycadeoidea as a generic name. In a later account of the Portland
stems Buckland[1078], in deference to Brongniart’s opinion, substituted
Brongniart’s name Cycadites for Cycadeoidea. It is noteworthy that no
reference is made in the original description to the occurrence of lateral
shoots among the persistent petiole-bases that encase the Portland stems,
but in a later account such shoots are represented in one of the figured
stems and are compared with the buds occasionally produced on stems of
the recent Cycads than is implied by the analogy of Taxus. Nathorst[1071], as
the result of his discovery of certain reproductive organs associated with
some Rhaetic fronds described as Dioonites spectabilis, proposed a third
subdivision, the Dioonitales, but he subsequently[1072] restored the fronds to
their original designation Nilssonia pterophylloides, and on further
examination found that the supposed microspore-bearing organs were
seeds. Nilssonia pterophylloides would therefore find a more natural place
in the class Nilssoniales instituted by Thomas[1073].
BENNETTITALES.
Cycadeoidea. Buckland.
In 1827 Buckland[1074] proposed the generic name Cycadeoidea for some
petrified stems from the Purbeck beds in the Isle of Portland and published
a description of two species, Cycadeoidea megalophylla and C.
microphylla. Brongniart[1075] considered Buckland’s term Cycadeoidea
inappropriate and proposed in its place Mantellia, the type-species being
Mantellia nidiformis Brongn., the Portland stem which Buckland a month
or two later called independently Cycadeoidea megalophylla. Subsequently
Brongniart[1076] withdrew Mantellia as it had been previously used by
Parkinson for a sponge and substituted Cycadites. Some years later
Carruthers[1077] revived Mantellia for a type of Cycadean stem from Portland
though one species, apparently indistinguishable from those referred to
Mantellia, he named Bennettites portlandicus. There is no adequate reason
for the retention of the generic name Mantellia. The close resemblance of
the short and thick stems (12–30 cm. in height) described by Buckland to
those of some recent Cycads was recognised by Robert Brown and
Loddiges and the former suggested to Buckland the inclusion of the fossils
in a new family Cycadeoideae. It was this suggestion that led Buckland to
adopt Cycadeoidea as a generic name. In a later account of the Portland
stems Buckland[1078], in deference to Brongniart’s opinion, substituted
Brongniart’s name Cycadites for Cycadeoidea. It is noteworthy that no
reference is made in the original description to the occurrence of lateral
shoots among the persistent petiole-bases that encase the Portland stems,
but in a later account such shoots are represented in one of the figured
stems and are compared with the buds occasionally produced on stems of
Page 407
Cycas[1079]. The subsequent researches of Carruthers[1080] demonstrated the
reproductive nature of precisely similar lateral shoots in the stem on which
he founded the genus Bennettites. The generic name Echinostipes given by
Pomel[1081], who had a passion for instituting new nomenclature, to
Buckland’s Portland stems has not been adopted: his genus Crossozamia
proposed for certain stems and fronds was revived by Carruthers[1082] but has
not been generally used. A further complication in the nomenclature of
Cycadean stems was introduced by Saporta’s institution[1083] of
Bulbopodium and Cylindropodium: in the former genus he included the
small ovoid stem figured by Lindley and Hutton as Cycadeoidea
pygmaea[1084] and two French Jurassic species which might reasonably be
assigned to Cycadeoidea. To Cylindropodium were referred some large
French stems from Jurassic strata: an examination of the type-specimens in
Paris convinced me that they are typical forms of Cycadeoidea. As
Ward[1085] has pointed out, both Saporta’s genera may be merged in
Cycadeoidea. Fliche and Zeiller[1086] also include the small globular stems
named by Saporta Bulbopodium in the older genus Cycadeoidea: one such
type from the Portlandian of Boulogne is described by these authors as
Cycadeoidea pumila. Saporta also proposed the name Platylepis[1087], the
type-species being Cycadeoidea micromyela Mor., from the Lias of
Calvados, which has recently been investigated by Lignier[1088] who wisely
adopts Morière’s designation. Another unnecessary generic name is
Schizopodium given by Morière to a stem, S. Renaulti[1089], regarded by
Lignier as indistinguishable specifically from C. micromyela.
The two names Cycadeoidea and Bennettites have been used by authors
for stems which are unquestionably generically identical and as is often the
case much confusion has been caused through the failure of palaeobotanists
to arrive at an agreement. Lester Ward, a staunch advocate of the rule of
priority, repeatedly pointed out that Buckland’s name Cycadeoidea should
take precedence of Bennettites on the ground that stems for which these
genera were instituted are clearly of the same type, and he added that the
older genus, though abandoned by its author, cannot be given up without
violating the inexorable rules of priority. On the other hand it has been
urged that the genus Bennettites as defined by Carruthers is characterised by
the possession of (i) fertile shoots bearing strobili and (ii) vegetative organs
exhibiting certain anatomical characters. Buckland’s species of
Cycadeoidea, though bearing lateral shoots, are not well enough preserved
reproductive nature of precisely similar lateral shoots in the stem on which
he founded the genus Bennettites. The generic name Echinostipes given by
Pomel[1081], who had a passion for instituting new nomenclature, to
Buckland’s Portland stems has not been adopted: his genus Crossozamia
proposed for certain stems and fronds was revived by Carruthers[1082] but has
not been generally used. A further complication in the nomenclature of
Cycadean stems was introduced by Saporta’s institution[1083] of
Bulbopodium and Cylindropodium: in the former genus he included the
small ovoid stem figured by Lindley and Hutton as Cycadeoidea
pygmaea[1084] and two French Jurassic species which might reasonably be
assigned to Cycadeoidea. To Cylindropodium were referred some large
French stems from Jurassic strata: an examination of the type-specimens in
Paris convinced me that they are typical forms of Cycadeoidea. As
Ward[1085] has pointed out, both Saporta’s genera may be merged in
Cycadeoidea. Fliche and Zeiller[1086] also include the small globular stems
named by Saporta Bulbopodium in the older genus Cycadeoidea: one such
type from the Portlandian of Boulogne is described by these authors as
Cycadeoidea pumila. Saporta also proposed the name Platylepis[1087], the
type-species being Cycadeoidea micromyela Mor., from the Lias of
Calvados, which has recently been investigated by Lignier[1088] who wisely
adopts Morière’s designation. Another unnecessary generic name is
Schizopodium given by Morière to a stem, S. Renaulti[1089], regarded by
Lignier as indistinguishable specifically from C. micromyela.
The two names Cycadeoidea and Bennettites have been used by authors
for stems which are unquestionably generically identical and as is often the
case much confusion has been caused through the failure of palaeobotanists
to arrive at an agreement. Lester Ward, a staunch advocate of the rule of
priority, repeatedly pointed out that Buckland’s name Cycadeoidea should
take precedence of Bennettites on the ground that stems for which these
genera were instituted are clearly of the same type, and he added that the
older genus, though abandoned by its author, cannot be given up without
violating the inexorable rules of priority. On the other hand it has been
urged that the genus Bennettites as defined by Carruthers is characterised by
the possession of (i) fertile shoots bearing strobili and (ii) vegetative organs
exhibiting certain anatomical characters. Buckland’s species of
Cycadeoidea, though bearing lateral shoots, are not well enough preserved
Page 408
to afford definite information as to the morphological features of the
strobili, nor have we satisfactory data with regard to the degree of
resemblance between the vegetative features of Bennettites and the Portland
stems. Carruthers laid stress on the elliptical section of the stele in
Bennettites in contrast to the cylindrical cylinder of Buckland’s
Cycadeoidea trunks. Subsequent research has shown that this difference is
not in itself a valid criterion either of generic or specific rank but, as
Wieland says, it is an open question to what extent the stem structure of
Cycadeoidea and Bennettites agrees. The probability is that were our
knowledge of the Portland stems less incomplete, they would be found to
possess no anatomical features inconsistent with this generic union.
Granting the correctness of this view, the adoption of the later generic term
would be a reasonable course to follow on the ground that it stands for
stems showing well preserved structure, while Cycadeoidea was in the first
instance applied to stems showing only partially preserved stumps of
strobili, and the name was not retained by its author. Graf Solms-
Laubach[1090] and some other authors have used Bennettites for Cycadean
stems possessing strobili of known structure such as those of Bennettites
Gibsonianus, reserving Cycadeoidea for similar stems but without strobili
sufficiently well preserved to afford evidence of morphological characters.
This practice I followed in 1895[1091], but my usage of the two generic
names has not been consistent, the name Cycadeoidea being afterwards
employed[1092] in a more comprehensive sense. The investigation of the
reproductive shoots of American Lower Cretaceous and Upper Jurassic
Cycadean stems[1093] has demonstrated the practical identity of their ovulate
strobili with those of the English Bennettites. It is clear that the American
stems as well as numerous specimens from Italy and other European
localities are generically inseparable from Bennettites. The adoption of
Cycadeoidea by Wieland, following Ward, has naturally strengthened the
claim of Buckland’s genus at least so far as wide usage is concerned, and
with some reluctance I propose to fall in with this terminology and for the
sake of convenience to give up the use of Bennettites. Among Mesozoic
Cycadean stems agreeing with those of recent genera in habit and in the
presence of an armour of persistent leaf-bases are several which afford no
evidence either of the occurrence of fertile shoots or of lateral shoots with
terminal flowers. To such stems the name Cycadeoidea has been applied,
the designation Bennettites being restricted to stems with lateral fertile
strobili, nor have we satisfactory data with regard to the degree of
resemblance between the vegetative features of Bennettites and the Portland
stems. Carruthers laid stress on the elliptical section of the stele in
Bennettites in contrast to the cylindrical cylinder of Buckland’s
Cycadeoidea trunks. Subsequent research has shown that this difference is
not in itself a valid criterion either of generic or specific rank but, as
Wieland says, it is an open question to what extent the stem structure of
Cycadeoidea and Bennettites agrees. The probability is that were our
knowledge of the Portland stems less incomplete, they would be found to
possess no anatomical features inconsistent with this generic union.
Granting the correctness of this view, the adoption of the later generic term
would be a reasonable course to follow on the ground that it stands for
stems showing well preserved structure, while Cycadeoidea was in the first
instance applied to stems showing only partially preserved stumps of
strobili, and the name was not retained by its author. Graf Solms-
Laubach[1090] and some other authors have used Bennettites for Cycadean
stems possessing strobili of known structure such as those of Bennettites
Gibsonianus, reserving Cycadeoidea for similar stems but without strobili
sufficiently well preserved to afford evidence of morphological characters.
This practice I followed in 1895[1091], but my usage of the two generic
names has not been consistent, the name Cycadeoidea being afterwards
employed[1092] in a more comprehensive sense. The investigation of the
reproductive shoots of American Lower Cretaceous and Upper Jurassic
Cycadean stems[1093] has demonstrated the practical identity of their ovulate
strobili with those of the English Bennettites. It is clear that the American
stems as well as numerous specimens from Italy and other European
localities are generically inseparable from Bennettites. The adoption of
Cycadeoidea by Wieland, following Ward, has naturally strengthened the
claim of Buckland’s genus at least so far as wide usage is concerned, and
with some reluctance I propose to fall in with this terminology and for the
sake of convenience to give up the use of Bennettites. Among Mesozoic
Cycadean stems agreeing with those of recent genera in habit and in the
presence of an armour of persistent leaf-bases are several which afford no
evidence either of the occurrence of fertile shoots or of lateral shoots with
terminal flowers. To such stems the name Cycadeoidea has been applied,
the designation Bennettites being restricted to stems with lateral fertile
Page 409
shoots: this practice of treating the absence of reproductive shoots as a
characteristic feature of Cycadeoidea is regarded by Wieland as illogical
and artificial; and if, as seems probable, he is correct in believing that the
majority of the Mesozoic Cycadean plants culminated their vegetative
period by prolific development of flowers, the absence of flowering
branches would be contingent on a certain stage of development and not a
generic character. Dr Stopes[1094] has recently published facts with regard to
the anatomical features of Cycadean stems which have a bearing on the
vexed question of nomenclature, but are more important from a
morphological point of view as they indicate a closer agreement between
certain types of Lower Cretaceous stems and those of Cycas and other
recent genera, in which successive rings of vascular tissue are developed,
than has previously been recognised. In her diagnosis of Cycadeoidea she
includes the following statement: ‘In its internal anatomy the trunk shows
two or more (up to eight are recorded) zones of secondary wood, the zones
composed of distinct series of tracheids each more or less regularly
arranged in radial sequence.’ It is claimed that the addition of this character
constitutes for the first time a clear distinction between Cycadeoidea and
Bennettites. Dr Stopes states that the two stems on which Buckland founded
the genus Cycadeoidea are lost and adds that Buckland’s type has certain
anatomical features which are not found in Bennettites. Buckland in his
description of C. microphylla states that there are ‘two laminated circles’ in
the stem instead of the usual single cylinder, a character suggestive of
Cycas. In the original figure of this species there are no indications of any
lateral fertile shoots though, as Dr Stopes says, many of the Portland stems
undoubtedly possessed such flowers. This author makes no reference to
Buckland’s later description of C. microphylla: in this it is stated that the
stem bears numerous buds rising from the axillae of petioles, and these are
shown in the illustration[1095]. Without access to the actual specimen it is
impossible to say whether or not the two ‘laminated circles’ described and
figured by Buckland[1096] are two distinct cylinders or parts of one cylinder
separated by the infiltration of some inorganic substance. In his description
of Cycadeoidea Yatesii Carruthers spoke of the occurrence of two cylinders
of wood, and this was confirmed in a subsequent account of the type-
specimen[1097]. Dr Stopes gives a fuller account of Carruthers’ type and re-
confirm a the existence of two vascular cylinders; she also describes a new
species, C. buzzardensis[1098] (fig. 578), in which there are 3–8 or more
characteristic feature of Cycadeoidea is regarded by Wieland as illogical
and artificial; and if, as seems probable, he is correct in believing that the
majority of the Mesozoic Cycadean plants culminated their vegetative
period by prolific development of flowers, the absence of flowering
branches would be contingent on a certain stage of development and not a
generic character. Dr Stopes[1094] has recently published facts with regard to
the anatomical features of Cycadean stems which have a bearing on the
vexed question of nomenclature, but are more important from a
morphological point of view as they indicate a closer agreement between
certain types of Lower Cretaceous stems and those of Cycas and other
recent genera, in which successive rings of vascular tissue are developed,
than has previously been recognised. In her diagnosis of Cycadeoidea she
includes the following statement: ‘In its internal anatomy the trunk shows
two or more (up to eight are recorded) zones of secondary wood, the zones
composed of distinct series of tracheids each more or less regularly
arranged in radial sequence.’ It is claimed that the addition of this character
constitutes for the first time a clear distinction between Cycadeoidea and
Bennettites. Dr Stopes states that the two stems on which Buckland founded
the genus Cycadeoidea are lost and adds that Buckland’s type has certain
anatomical features which are not found in Bennettites. Buckland in his
description of C. microphylla states that there are ‘two laminated circles’ in
the stem instead of the usual single cylinder, a character suggestive of
Cycas. In the original figure of this species there are no indications of any
lateral fertile shoots though, as Dr Stopes says, many of the Portland stems
undoubtedly possessed such flowers. This author makes no reference to
Buckland’s later description of C. microphylla: in this it is stated that the
stem bears numerous buds rising from the axillae of petioles, and these are
shown in the illustration[1095]. Without access to the actual specimen it is
impossible to say whether or not the two ‘laminated circles’ described and
figured by Buckland[1096] are two distinct cylinders or parts of one cylinder
separated by the infiltration of some inorganic substance. In his description
of Cycadeoidea Yatesii Carruthers spoke of the occurrence of two cylinders
of wood, and this was confirmed in a subsequent account of the type-
specimen[1097]. Dr Stopes gives a fuller account of Carruthers’ type and re-
confirm a the existence of two vascular cylinders; she also describes a new
species, C. buzzardensis[1098] (fig. 578), in which there are 3–8 or more
Page 410
cylinders. Neither of these stems affords any evidence of the possession of
fertile shoots; they agree closely with stems of the Bucklandia type in their
comparatively slender habit and differ in this respect from Buckland’s
Portland species. The occurrence of more than one vascular cylinder in the
stems Cycadeoidea (= Bucklandia) Yatesii and C. (= Bucklandia)
buzzardensis suggests the possibility that this feature was characteristic of
other species included in Bucklandia.
It is clear that some at least of the stems referred to the genus Bucklandia
bore flowers of the Williamsonia type[1099], and it is not improbable that the
stems described by Dr Stopes as Cycadeoidea Yatesii and C. buzzardensis
(fig. 578) possessed fertile shoots comparable with those of the Middle
Jurassic species W. gigas. Dr Stopes’s contribution, while establishing a
close agreement in anatomical features between some Lower Cretaceous
stems and those of Cycas, does not warrant the further conclusion that these
stems were in other morphological characters closely allied to modern
Cycads. The main features of Cycadeoidea may be summarised as follows:
The principal trunk is generally unbranched (fig. 507) and identical in habit
with some species of Macrozamia, Dioon, and Encephalartos (cf. figs. 379,
382); in some species, e.g. Cycadeoidea Marshiana, C. superba[1100], C.
nana[1101], the plant is represented by several approximately equal, thick,
tuberous stems, in some cases easily separated from one another: a similar
clustered habit is exhibited by certain forms of Encephalartos. The size of a
Cycadeoidea trunk varies from a few centimetres in length with a diameter
of similar dimensions, as in C. pumila, to over a metre long as in C.
gigantea (fig. 535), or as much as 3–4 metres in C. Jenneyana with a
diameter of about half a metre. The surface is covered with persistent leaf-
bases, exactly as in many recent Cycads, embedded in a thick mass of
ramental scales which often stand out as a prominent reticulum, the petioles
having partially decayed before the penetration of the mineralising solution
through their harder tissues (fig. 507). On the conical terminal bud
preserved in some stems (fig. 536) the foliage-leaves are replaced by linear
scales. The leaf-bases often show the vascular bundles which form a
simpler system than in the majority of recent species, their arrangement
being, as Wieland says, more Fern-like; they form a series of collateral
strands following the outline of the petiole-base[1102] with a U-shaped
invagination in the middle of the upper face (fig. 517, A). Beyond the
structure of the bundles at the base of the fronds and in the cortex of the
fertile shoots; they agree closely with stems of the Bucklandia type in their
comparatively slender habit and differ in this respect from Buckland’s
Portland species. The occurrence of more than one vascular cylinder in the
stems Cycadeoidea (= Bucklandia) Yatesii and C. (= Bucklandia)
buzzardensis suggests the possibility that this feature was characteristic of
other species included in Bucklandia.
It is clear that some at least of the stems referred to the genus Bucklandia
bore flowers of the Williamsonia type[1099], and it is not improbable that the
stems described by Dr Stopes as Cycadeoidea Yatesii and C. buzzardensis
(fig. 578) possessed fertile shoots comparable with those of the Middle
Jurassic species W. gigas. Dr Stopes’s contribution, while establishing a
close agreement in anatomical features between some Lower Cretaceous
stems and those of Cycas, does not warrant the further conclusion that these
stems were in other morphological characters closely allied to modern
Cycads. The main features of Cycadeoidea may be summarised as follows:
The principal trunk is generally unbranched (fig. 507) and identical in habit
with some species of Macrozamia, Dioon, and Encephalartos (cf. figs. 379,
382); in some species, e.g. Cycadeoidea Marshiana, C. superba[1100], C.
nana[1101], the plant is represented by several approximately equal, thick,
tuberous stems, in some cases easily separated from one another: a similar
clustered habit is exhibited by certain forms of Encephalartos. The size of a
Cycadeoidea trunk varies from a few centimetres in length with a diameter
of similar dimensions, as in C. pumila, to over a metre long as in C.
gigantea (fig. 535), or as much as 3–4 metres in C. Jenneyana with a
diameter of about half a metre. The surface is covered with persistent leaf-
bases, exactly as in many recent Cycads, embedded in a thick mass of
ramental scales which often stand out as a prominent reticulum, the petioles
having partially decayed before the penetration of the mineralising solution
through their harder tissues (fig. 507). On the conical terminal bud
preserved in some stems (fig. 536) the foliage-leaves are replaced by linear
scales. The leaf-bases often show the vascular bundles which form a
simpler system than in the majority of recent species, their arrangement
being, as Wieland says, more Fern-like; they form a series of collateral
strands following the outline of the petiole-base[1102] with a U-shaped
invagination in the middle of the upper face (fig. 517, A). Beyond the
structure of the bundles at the base of the fronds and in the cortex of the
Page 411
stem our knowledge of the anatomy of the vascular supply of the rachises is
very meagre. At the petiole-base each bundle consists either entirely of
radial rows of centrifugal scalariform tracheids and medullary rays usually
one-cell broad (fig. 519, B) or of centrifugal and centripetal xylem in
varying proportions. The ground-tissue is well supplied with large secretory
canals and in the larger leaf-bases there is a considerable development of
periderm at the surface (fig. 517, B) as in recent Cycads. The ramenta
formed from the epidermal cells consist in most species of fairly broad
scales one-cell thick at the edges and broader in the middle; in Cycadeoidea
nigra[1103] they are generally one-cell thick throughout and similar ramenta
are common in C. Gibsoniana (fig. 517, B). In C. micromyela unicellular
hairs replace the scaly ramenta, but transitional forms occur between hairs
and scales. In Williamsonia scotica (fig. 562) and in an Indian species of
that genus the ramenta are exclusively long hairs as in recent Cycads, the
scale-form of the ramenta in Cycadeoidea being a Fern-character. The
degree of development of the ramental tissue varies in different species; in
C. Stilwelli and C. excelsa it is feebly developed while in Cycadeoidea
micromyela the ramenta almost cover the exposed leaf-base armour. The
exceptional abundance of the ramental scales is a striking characteristic of
some American stems referred to a separate genus, Cycadella[1104]. In the
abundance of the ramental tissue, in the compact structure of the well
protected cones, and in the thickly cuticularised epidermis of the bracts and
leaves Cycadeoidea exhibits xerophilous characters in a very high degree.
very meagre. At the petiole-base each bundle consists either entirely of
radial rows of centrifugal scalariform tracheids and medullary rays usually
one-cell broad (fig. 519, B) or of centrifugal and centripetal xylem in
varying proportions. The ground-tissue is well supplied with large secretory
canals and in the larger leaf-bases there is a considerable development of
periderm at the surface (fig. 517, B) as in recent Cycads. The ramenta
formed from the epidermal cells consist in most species of fairly broad
scales one-cell thick at the edges and broader in the middle; in Cycadeoidea
nigra[1103] they are generally one-cell thick throughout and similar ramenta
are common in C. Gibsoniana (fig. 517, B). In C. micromyela unicellular
hairs replace the scaly ramenta, but transitional forms occur between hairs
and scales. In Williamsonia scotica (fig. 562) and in an Indian species of
that genus the ramenta are exclusively long hairs as in recent Cycads, the
scale-form of the ramenta in Cycadeoidea being a Fern-character. The
degree of development of the ramental tissue varies in different species; in
C. Stilwelli and C. excelsa it is feebly developed while in Cycadeoidea
micromyela the ramenta almost cover the exposed leaf-base armour. The
exceptional abundance of the ramental scales is a striking characteristic of
some American stems referred to a separate genus, Cycadella[1104]. In the
abundance of the ramental tissue, in the compact structure of the well
protected cones, and in the thickly cuticularised epidermis of the bracts and
leaves Cycadeoidea exhibits xerophilous characters in a very high degree.
Page 412
Fig. 507. Cycadeoidea marylandica. The first American stem to be
described. On the side of the stem shown in the photograph there
are about 30 young strobili scattered among the leaf-bases. (After
Wieland; ¼ nat. size.)
described. On the side of the stem shown in the photograph there
are about 30 young strobili scattered among the leaf-bases. (After
Wieland; ¼ nat. size.)
Page 413
Fig. 508. Cycadeoidea Wielandi. Transverse sections of the secondary
xylem of the stem. A, the middle region; B, the inner edge of the
xylem. (After Wieland; × 100.)
With very few exceptions the stems of Cycadeoidea so far described
afford no satisfactory evidence of the presence of more than one vascular
cylinder in the main stem: in this respect Cycadeoidea agrees with such
recent Cycads as Dioon, Ceratozamia, and Stangeria. In the stem of C.
Jenneyana the secondary vascular tissue reaches a considerable thickness
and shows signs of ‘rings’ in the xylem, but these are probably the result of
some periodic interference with the uniform growth and not an indication of
more than one xylem-cylinder. The secondary xylem (figs. 508, 509)
consists only of centrifugal tracheids with some spiral elements on the inner
edge; though manoxylic, Cycadeoidea has more compact wood than that of
recent Cycads; the medullary rays are 1–2 cells broad except near the
perimedullary region where they are broader and the individual cells are
tangentially stretched (fig. 508, B). The tracheids are scalariform, but in C.
xylem of the stem. A, the middle region; B, the inner edge of the
xylem. (After Wieland; × 100.)
With very few exceptions the stems of Cycadeoidea so far described
afford no satisfactory evidence of the presence of more than one vascular
cylinder in the main stem: in this respect Cycadeoidea agrees with such
recent Cycads as Dioon, Ceratozamia, and Stangeria. In the stem of C.
Jenneyana the secondary vascular tissue reaches a considerable thickness
and shows signs of ‘rings’ in the xylem, but these are probably the result of
some periodic interference with the uniform growth and not an indication of
more than one xylem-cylinder. The secondary xylem (figs. 508, 509)
consists only of centrifugal tracheids with some spiral elements on the inner
edge; though manoxylic, Cycadeoidea has more compact wood than that of
recent Cycads; the medullary rays are 1–2 cells broad except near the
perimedullary region where they are broader and the individual cells are
tangentially stretched (fig. 508, B). The tracheids are scalariform, but in C.
Page 414
micromyela, an exceptional type, some of the xylem-elements have 1–2
rows of separate bordered pits (fig. 538). The phloem (fig. 518, B) is
characterised by an alternation of thick-walled elements and thinner
cells[1105]. From the main stele branches are given off to supply the flowering
shoots in the form of a cylindrical stele like that of the primary axis, and
each leaf-trace arises as a single bundle which, in the form of a U-shaped
strand (fig. 519, A), pursues a straight course to the leaf-base (fig. 510)
where it breaks up into several branches (fig. 538, B). Both leaf-trace and
peduncle stele are given off from the lower edge of a medullary ray. In the
parenchymatous cortex large secretory canals (fig. 518, B) are a
conspicuous feature, and accessory cortical steles similar to those in Cycas
occasionally occur (fig. 511). The large pith consists of parenchyma and
secretory canals, and internal periderm[1106] may be present; no medullary
bundles have been discovered.
rows of separate bordered pits (fig. 538). The phloem (fig. 518, B) is
characterised by an alternation of thick-walled elements and thinner
cells[1105]. From the main stele branches are given off to supply the flowering
shoots in the form of a cylindrical stele like that of the primary axis, and
each leaf-trace arises as a single bundle which, in the form of a U-shaped
strand (fig. 519, A), pursues a straight course to the leaf-base (fig. 510)
where it breaks up into several branches (fig. 538, B). Both leaf-trace and
peduncle stele are given off from the lower edge of a medullary ray. In the
parenchymatous cortex large secretory canals (fig. 518, B) are a
conspicuous feature, and accessory cortical steles similar to those in Cycas
occasionally occur (fig. 511). The large pith consists of parenchyma and
secretory canals, and internal periderm[1106] may be present; no medullary
bundles have been discovered.
Page 415
Fig. 509. Cycadeoidea Wielandi. Tangential section of secondary xylem
of the stem. (After Wieland; × 100.)
of the stem. (After Wieland; × 100.)
Page 416
Fig. 510. Cycadeoidea sp. A piece of stem showing (A) the persistent
leaf-bases in side-view and at b the scars where the bases have
broken off, and (B) the inner face of the same piece with the
exposed leaf-traces passing into the leaves; one of the traces is seen
at t in fig. A. (From a specimen in the British Museum; ½ nat.
size.)
Fig. 511. Cycadeoidea Gibsoniana. Stele in the cortex. (British Museum,
8406.)
leaf-bases in side-view and at b the scars where the bases have
broken off, and (B) the inner face of the same piece with the
exposed leaf-traces passing into the leaves; one of the traces is seen
at t in fig. A. (From a specimen in the British Museum; ½ nat.
size.)
Fig. 511. Cycadeoidea Gibsoniana. Stele in the cortex. (British Museum,
8406.)
Page 417
Fig. 512. Cycadeoidea ingens. Transverse section of a young frond,
above the tip of the rachis, embedded in ramenta. The rachis is
situated on the upper side of the two ranks of pinnae. The arrow
points towards the axis of the stem. (After Wieland; × 4.)
The correlation of the numerous fronds[1107] preserved in Mesozoic strata
with their parent-stems is seldom possible. It is known that leaves of the
Zamites type were borne on stems (Bucklandia) agreeing with Cycadeoidea
in certain features but differing in the habit of the fertile shoots (fig. 542),
and there is evidence that similar stems bore Ptilophyllum and
Dictyozamites fronds[1108]; but only unexpanded leaves have been found in
actual connexion with Cycadeoidea stems. Wieland[1109] discovered young
above the tip of the rachis, embedded in ramenta. The rachis is
situated on the upper side of the two ranks of pinnae. The arrow
points towards the axis of the stem. (After Wieland; × 4.)
The correlation of the numerous fronds[1107] preserved in Mesozoic strata
with their parent-stems is seldom possible. It is known that leaves of the
Zamites type were borne on stems (Bucklandia) agreeing with Cycadeoidea
in certain features but differing in the habit of the fertile shoots (fig. 542),
and there is evidence that similar stems bore Ptilophyllum and
Dictyozamites fronds[1108]; but only unexpanded leaves have been found in
actual connexion with Cycadeoidea stems. Wieland[1109] discovered young
Page 418
pinnate fronds, agreeing in the form of the pinnae with Zamites and with
some forms of Encephalartos, embedded in a thick mass of ramental scales
in the terminal bud of a stem: the rachises were erect and the two-ranked
pinnae imbricate and folded inwards (fig. 512), the vernation being like that
of Dioon and not circinate as in Cycas and Ferns. The mesophyll of the
leathery pinnae is differentiated into palisade and lacunar parenchyma, and
the bundles are said to be ‘mesarch’ though on this point more information
is desirable. Each bundle is surrounded by a sheath of thick-walled cells and
the same tissue forms I-shaped girders as in similar recent leaves. In one
species, Cycadella ramentosa[1110], the rachis of a young frond found among
the leaf-bases had a broad U-shaped vascular strand.
In most Cycadeoidea stems a characteristic feature is the occurrence of
reduced leaves, or bracts, arranged spirally about a cone which sometimes
projects slightly beyond the general level of the persistent leaf-bases, or the
cones may be fully developed yet still more or less hidden within the
armour of petiole-bases (fig. 517, C). These cones, or flowers, are borne at
the apex of lateral axillary shoots, and it is characteristic of the genus that
they never project more than a very short distance beyond the truncate
stumps of the old leaf-bases. The axis of a flowering branch bears numerous
linear, hairy, bracts (figs. 513; 514, b) which with their thick felt of ramenta
constitute an efficient protective investment. The summit of a fertile shoot
forms a rounded hemispherical cushion (fig. 514), or the receptacle may be
more elongate and conical (fig. 513) and in some species pyriform[1111]. The
flowers are generally bisporangiate, but the fact that in flowers with mature
microsporophylls the ovules are small and apparently immature (fig. 513)
makes it difficult to determine whether the megasporophylls are merely
immature or functionless as in the male flower of Welwitschia (cf. fig. 818).
It would seem, however, that in most cases the flowers were bisexual[1112]
(fig. 513). A remarkable feature is the enormous number of flowers on a
single stem; in Cycadeoidea Dartoni[1113], 54 cm. long and 35 cm. broad,
500–600 flowers were counted on one side. On the other hand the large
stem of C. gigantea (fig. 536) shows no flowers. All the flowers on a single
trunk are approximately in the same stage of development: it would seem,
as Wieland points out, that after a vegetative period of some considerable
duration the plant produced a large crop of flowers, and it is conceivable
that as in Corypha and some other recent Flowering plants this supreme
some forms of Encephalartos, embedded in a thick mass of ramental scales
in the terminal bud of a stem: the rachises were erect and the two-ranked
pinnae imbricate and folded inwards (fig. 512), the vernation being like that
of Dioon and not circinate as in Cycas and Ferns. The mesophyll of the
leathery pinnae is differentiated into palisade and lacunar parenchyma, and
the bundles are said to be ‘mesarch’ though on this point more information
is desirable. Each bundle is surrounded by a sheath of thick-walled cells and
the same tissue forms I-shaped girders as in similar recent leaves. In one
species, Cycadella ramentosa[1110], the rachis of a young frond found among
the leaf-bases had a broad U-shaped vascular strand.
In most Cycadeoidea stems a characteristic feature is the occurrence of
reduced leaves, or bracts, arranged spirally about a cone which sometimes
projects slightly beyond the general level of the persistent leaf-bases, or the
cones may be fully developed yet still more or less hidden within the
armour of petiole-bases (fig. 517, C). These cones, or flowers, are borne at
the apex of lateral axillary shoots, and it is characteristic of the genus that
they never project more than a very short distance beyond the truncate
stumps of the old leaf-bases. The axis of a flowering branch bears numerous
linear, hairy, bracts (figs. 513; 514, b) which with their thick felt of ramenta
constitute an efficient protective investment. The summit of a fertile shoot
forms a rounded hemispherical cushion (fig. 514), or the receptacle may be
more elongate and conical (fig. 513) and in some species pyriform[1111]. The
flowers are generally bisporangiate, but the fact that in flowers with mature
microsporophylls the ovules are small and apparently immature (fig. 513)
makes it difficult to determine whether the megasporophylls are merely
immature or functionless as in the male flower of Welwitschia (cf. fig. 818).
It would seem, however, that in most cases the flowers were bisexual[1112]
(fig. 513). A remarkable feature is the enormous number of flowers on a
single stem; in Cycadeoidea Dartoni[1113], 54 cm. long and 35 cm. broad,
500–600 flowers were counted on one side. On the other hand the large
stem of C. gigantea (fig. 536) shows no flowers. All the flowers on a single
trunk are approximately in the same stage of development: it would seem,
as Wieland points out, that after a vegetative period of some considerable
duration the plant produced a large crop of flowers, and it is conceivable
that as in Corypha and some other recent Flowering plants this supreme
Page 419
effort set a limit to the plant’s existence. In the development of flowers from
the old stem Cycadeoidea affords a striking example of cauliflory.
Fig. 513. Cycadeoidea. Restoration of an unexpanded bisporangiate
strobilus with some of the hairy bracts removed. Compare
Cycadeoidea dacotensis, figs. 529, 530. (After Wieland; ca nat. size.)
the old stem Cycadeoidea affords a striking example of cauliflory.
Fig. 513. Cycadeoidea. Restoration of an unexpanded bisporangiate
strobilus with some of the hairy bracts removed. Compare
Cycadeoidea dacotensis, figs. 529, 530. (After Wieland; ca nat. size.)
Page 420
Fig. 514. Ovulate strobilus of Cycadeoidea. Longitudinal section
showing the pith, m, stele, x, p, and cortex, c, of the stem, the
ovulate strobilus with bracts, b, seeds, s, etc., enclosed by foliage-
leaves, l; a, insertion of leaves on the stem; d, insertion of disc of
microsporophylls. (After Wieland.)
The structure of the flowers is one of the most obvious differences
between Cycadeoidea and recent Cycads (cf. figs. 393, 394). The bisexual
flowers of the fossil stems are comparatively small, not exceeding a few
centimetres in length, like a hen’s egg or a medium-sized pear and in
showing the pith, m, stele, x, p, and cortex, c, of the stem, the
ovulate strobilus with bracts, b, seeds, s, etc., enclosed by foliage-
leaves, l; a, insertion of leaves on the stem; d, insertion of disc of
microsporophylls. (After Wieland.)
The structure of the flowers is one of the most obvious differences
between Cycadeoidea and recent Cycads (cf. figs. 393, 394). The bisexual
flowers of the fossil stems are comparatively small, not exceeding a few
centimetres in length, like a hen’s egg or a medium-sized pear and in
Page 421
marked contrast to the male and female cones of modern Cycads (cf. figs.
393, 394). A verticil of pinnate microsporophylls is attached by a circular
collar formed of the concrescent bases of the sporophylls to the lower
portion of the receptacle; each pinnule bears several shortly-stalked
synangia divided into loculi containing microspores usually with smooth
walls and similar, except in their larger size, to those of modern Cycads
(fig. 532). Sections of some microspores figured by Wieland[1114] show what
appear to be cells in the spore-cavity, but they are larger than ordinary
prothallial cells and their true nature is doubtful. We lack information both
as regards the nature of the male gametes and the tissue formed on the
germination of the spores. The free portions of the microsporophyll-whorl
may consist of as many as 20 pinnate sporophylls, but the number is
generally smaller; these are much longer than the ovulate part of the flower
and in an immature state the ends of the sporophylls are bent inwards and
downwards (fig. 513) between the bracts and the receptacle. After
expanding and shedding the spores the whole male disc is thrown off
leaving a narrow rim below the hemispherical or conical receptacle (fig.
514, d). The sterile distal end of a microsporophyll is generally slightly
expanded and spathulate; in C. colossalis[1115] it bears a pair of wing-like
appendages (fig. 533).
The upper part of the receptacle is covered with two kinds of organs
which together form a layer of uniform depth; these are believed to be
homologous, foliar structures; the majority are sterile and have the form of
slender long and narrow appendages (fig. 514) each normally with a single
axial vascular strand. These so-called interseminal scales increase in
breadth in the apical region and form polygonal summits less than a
millimetre in breadth or exceeding 2 mm. The low pyramidal apices of the
interseminal scales give a mosaic-like appearance to the surface of the
ovulate receptacle (fig. 515). In the lower part of the receptacle these sterile
sporophylls are the only appendages, but over the greater part of the
receptacle they are intermixed with a smaller number of similar appendages
which bear a single terminal orthotropous ovule (fig. 514, s). Each ovule-
bearing organ or megasporophyll (seed-stalk) is surrounded by 5—6
interseminal scales, and the narrow cylindrical micropylar tubes are readily
distinguished from the sterile sporophylls in surface-view (figs. 516, 564).
The seeds appear to be exalbuminous and the embryo is dicotyledonous
(figs. 516, 521, 523)[1116]. The seeds are very small in comparison with those
393, 394). A verticil of pinnate microsporophylls is attached by a circular
collar formed of the concrescent bases of the sporophylls to the lower
portion of the receptacle; each pinnule bears several shortly-stalked
synangia divided into loculi containing microspores usually with smooth
walls and similar, except in their larger size, to those of modern Cycads
(fig. 532). Sections of some microspores figured by Wieland[1114] show what
appear to be cells in the spore-cavity, but they are larger than ordinary
prothallial cells and their true nature is doubtful. We lack information both
as regards the nature of the male gametes and the tissue formed on the
germination of the spores. The free portions of the microsporophyll-whorl
may consist of as many as 20 pinnate sporophylls, but the number is
generally smaller; these are much longer than the ovulate part of the flower
and in an immature state the ends of the sporophylls are bent inwards and
downwards (fig. 513) between the bracts and the receptacle. After
expanding and shedding the spores the whole male disc is thrown off
leaving a narrow rim below the hemispherical or conical receptacle (fig.
514, d). The sterile distal end of a microsporophyll is generally slightly
expanded and spathulate; in C. colossalis[1115] it bears a pair of wing-like
appendages (fig. 533).
The upper part of the receptacle is covered with two kinds of organs
which together form a layer of uniform depth; these are believed to be
homologous, foliar structures; the majority are sterile and have the form of
slender long and narrow appendages (fig. 514) each normally with a single
axial vascular strand. These so-called interseminal scales increase in
breadth in the apical region and form polygonal summits less than a
millimetre in breadth or exceeding 2 mm. The low pyramidal apices of the
interseminal scales give a mosaic-like appearance to the surface of the
ovulate receptacle (fig. 515). In the lower part of the receptacle these sterile
sporophylls are the only appendages, but over the greater part of the
receptacle they are intermixed with a smaller number of similar appendages
which bear a single terminal orthotropous ovule (fig. 514, s). Each ovule-
bearing organ or megasporophyll (seed-stalk) is surrounded by 5—6
interseminal scales, and the narrow cylindrical micropylar tubes are readily
distinguished from the sterile sporophylls in surface-view (figs. 516, 564).
The seeds appear to be exalbuminous and the embryo is dicotyledonous
(figs. 516, 521, 523)[1116]. The seeds are very small in comparison with those
Page 422
of living Cycads. The structure of the megasporophylls, both sterile and
fertile, is described in more detail in the account of Cycadeoidea Morierei
and other forms. Fig. 516 represents a longitudinal section of one of the
smallest seeds of Cycadeoidea, between 3 and 4 mm. long; an embryo
occupies the greater part of the seed-cavity: the micropylar tube is formed
of three layers, a strong inner palisade-layer, a thin middle layer, and an
outer palisade-tissue, the interior of the tube being filled with parenchyma;
at the shoulder of the seed above the root-end of the embryo the surface of
the testa is characterised by 5–6 wings formed by the radial extension of
palisade-cells. After the shedding of the spores and the abscission of the
microsporophylls the flowering shoot probably increased slightly in length,
thus pushing the ripening seeds beyond the ends of the surrounding leaf-
bases. The ripe flowers were eventually cut off by an absciss-layer
immediately below the receptacle (figs. 521, C, a; 522, a), large cup-like
depressions being left on the surface of the stem (fig. 534). The ovulate
cone on which the species Cycadeoidea Morierei is founded probably
represents the condition of a naturally detached flower of a Cycadeoidea. It
is possible that the detached flowers freed from their encircling bracts may
have been edible, the small seeds being dispersed by animal agency.
fertile, is described in more detail in the account of Cycadeoidea Morierei
and other forms. Fig. 516 represents a longitudinal section of one of the
smallest seeds of Cycadeoidea, between 3 and 4 mm. long; an embryo
occupies the greater part of the seed-cavity: the micropylar tube is formed
of three layers, a strong inner palisade-layer, a thin middle layer, and an
outer palisade-tissue, the interior of the tube being filled with parenchyma;
at the shoulder of the seed above the root-end of the embryo the surface of
the testa is characterised by 5–6 wings formed by the radial extension of
palisade-cells. After the shedding of the spores and the abscission of the
microsporophylls the flowering shoot probably increased slightly in length,
thus pushing the ripening seeds beyond the ends of the surrounding leaf-
bases. The ripe flowers were eventually cut off by an absciss-layer
immediately below the receptacle (figs. 521, C, a; 522, a), large cup-like
depressions being left on the surface of the stem (fig. 534). The ovulate
cone on which the species Cycadeoidea Morierei is founded probably
represents the condition of a naturally detached flower of a Cycadeoidea. It
is possible that the detached flowers freed from their encircling bracts may
have been edible, the small seeds being dispersed by animal agency.
Page 423
Fig. 515. Cycadeoidea sp. Surface-view of a young ovulate strobilus
showing the swollen ends of interseminal scales grouped about the
circular micropyles. (After Wieland; × 10.)
The splendid petrified stem, Cycadeoidea etrusca Cap.[1117], one of the
treasures of the Bologna Museum, was found on a tomb 20 miles west of
that city where it was doubtless placed by the Etruscans who obtained it
from the Upper Jurassic scaly clays in the Apennine Hills. It was in an
imperfectly preserved flower of this fossil that Graf Solms-Laubach
discovered some microspores, but it was not until Wieland’s examination of
the more complete American stems that information was obtained as to the
spore-bearing organs. Another Italian stem, Cycadeoidea montiana Cap.,
was described in 1753 as a ‘congeries of barnacles[1118].’ The specimen
named by Goeppert Raumeria Reichenbachiana[1119] was described in the
middle of the eighteenth century as a mass of Hippurites or coral cups: this
showing the swollen ends of interseminal scales grouped about the
circular micropyles. (After Wieland; × 10.)
The splendid petrified stem, Cycadeoidea etrusca Cap.[1117], one of the
treasures of the Bologna Museum, was found on a tomb 20 miles west of
that city where it was doubtless placed by the Etruscans who obtained it
from the Upper Jurassic scaly clays in the Apennine Hills. It was in an
imperfectly preserved flower of this fossil that Graf Solms-Laubach
discovered some microspores, but it was not until Wieland’s examination of
the more complete American stems that information was obtained as to the
spore-bearing organs. Another Italian stem, Cycadeoidea montiana Cap.,
was described in 1753 as a ‘congeries of barnacles[1118].’ The specimen
named by Goeppert Raumeria Reichenbachiana[1119] was described in the
middle of the eighteenth century as a mass of Hippurites or coral cups: this
Page 424
was found in a swamp in Galicia and is now one of
the most striking objects in the Dresden Museum; a
brief account of it is given on page 409. In 1859
Tyson discovered two large trunks in the Potomac
beds of Maryland for which Fontaine subsequently
proposed the name Tysonia marylandica[1120], but as
Ward pointed out the species is clearly a Cycadeoidea
(fig. 507). In 1894 Lester Ward[1121] recorded several
additional stems from Tyson’s locality. It is, however,
from the Black Hills of Dakota, an isolated spur of the
Rocky Mountains, formed of older rocks encircled by
Lower Cretaceous strata[1122], that the greatest number
of Cycadean trunks have been obtained: the
magnificent collection now in the Yale Museum is
largely due to the energy and munificence of the late
Prof. Marsh. From the Upper Jurassic beds in Carbon
Co., Wyoming[1123], several stems have been collected,
and a preliminary study of their external features led
Ward to institute 20 species of a new genus Cycadella.
Stems have also been discovered in the Freezout Hills
of Wyoming and additional specimens have been
found in the Potomac formation of Maryland. The
discovery of over 1000 specimens of Cycadean stems Fig. 516.
in the Lower Cretaceous and Upper Jurassic beds of a Cycadeoidea
few localities in the United States bears striking Dartoni.
testimony to the abundance of these extinct Longitudinal
Gymnosperms during the latter part of the Mesozoic section of seed
era. It is perhaps true that, as Lester Ward wrote, with embryo.
‘Cycads are to the vegetable kingdom what Dinosaurs (After Wieland; ×
are to the animal, each representing the culmination in 19.)
Mesozoic times of the ruling Dynasties in the life of their age[1124].’
Although the number of stems obtained from European countries is
relatively small, the abundance of specimens in the Upper Jurassic strata of
the Isle of Portland and Northern Italy and their occurrence in Belgium[1125],
France, Germany, Austria, Poland, India and elsewhere, together with an
abundance of Cycadean fronds in practically all Jurassic and Lower
Cretaceous plant-bearing beds, demonstrate the dominant position of the
the most striking objects in the Dresden Museum; a
brief account of it is given on page 409. In 1859
Tyson discovered two large trunks in the Potomac
beds of Maryland for which Fontaine subsequently
proposed the name Tysonia marylandica[1120], but as
Ward pointed out the species is clearly a Cycadeoidea
(fig. 507). In 1894 Lester Ward[1121] recorded several
additional stems from Tyson’s locality. It is, however,
from the Black Hills of Dakota, an isolated spur of the
Rocky Mountains, formed of older rocks encircled by
Lower Cretaceous strata[1122], that the greatest number
of Cycadean trunks have been obtained: the
magnificent collection now in the Yale Museum is
largely due to the energy and munificence of the late
Prof. Marsh. From the Upper Jurassic beds in Carbon
Co., Wyoming[1123], several stems have been collected,
and a preliminary study of their external features led
Ward to institute 20 species of a new genus Cycadella.
Stems have also been discovered in the Freezout Hills
of Wyoming and additional specimens have been
found in the Potomac formation of Maryland. The
discovery of over 1000 specimens of Cycadean stems Fig. 516.
in the Lower Cretaceous and Upper Jurassic beds of a Cycadeoidea
few localities in the United States bears striking Dartoni.
testimony to the abundance of these extinct Longitudinal
Gymnosperms during the latter part of the Mesozoic section of seed
era. It is perhaps true that, as Lester Ward wrote, with embryo.
‘Cycads are to the vegetable kingdom what Dinosaurs (After Wieland; ×
are to the animal, each representing the culmination in 19.)
Mesozoic times of the ruling Dynasties in the life of their age[1124].’
Although the number of stems obtained from European countries is
relatively small, the abundance of specimens in the Upper Jurassic strata of
the Isle of Portland and Northern Italy and their occurrence in Belgium[1125],
France, Germany, Austria, Poland, India and elsewhere, together with an
abundance of Cycadean fronds in practically all Jurassic and Lower
Cretaceous plant-bearing beds, demonstrate the dominant position of the
Page 425
Bennettitales. The occurrence of the genus Williamsonia in many European
localities as well as in India, Afghanistan, and other countries, and the not
infrequent occurrence of stems assigned to Bucklandia, Yatesia,
Cylindropodium, and other genera furnish evidence of the rich development
of the Bennettitales in later Jurassic and Lower Cretaceous floras. Wieland’s
recent discovery[1126] of numerous Cycadean fronds, Williamsonia flowers,
and stems in Liassic rocks in Mexico shows that the group had already
assumed an important position in the early part of the Jurassic period.
The memoir by Carruthers[1127] on British Cycadean stems contains the
first account of the morphological features of Bennettitalean flowers based
on petrified material. In 1891 Solms-Laubach contributed an important
paper on the Bennettitean flower and several years later Lignier[1128]
contributed additional data derived from a careful study of a well preserved
strobilus[1129] from the Gault of Normandy. Wieland’s researches[1130] added
very greatly to our knowledge, particularly with regard to the morphology
of the microsporophylls. Among the earlier descriptions of the reproductive
organs of the Bennettitales is Buckland’s account[1131] of a specimen from
the Inferior Oolite of Charmouth, Dorset (fig. 560), which he referred to the
genus Podocarya (= Williamsonia Bucklandi[1132]): a thorough examination
of the type-specimen, which unfortunately cannot be found, would probably
furnish many important facts.
{ Cycadeoidea (Bennettites) Gibsoniana (Carruthers).
Cycadeoidea (Bennettites) Saxbyana (Brown).
These two species serve to illustrate the type of stem for which
Carruthers instituted the tribe Bennettiteae and the genus Bennettites.
Bennettites Gibsonianus is the most important of the five species described
by Carruthers[1133], as it was from its fertile shoots that information was first
obtained as to the nature of the ovulate strobili of the Bennettitales. B.
Saxbyanus[1134], originally described as Cycadites Saxbyanus from a
specimen found by Mr Saxby at Bonchurch in the Isle of Wight and
represented by Wealden examples from Brook Point, is chiefly interesting
for the clear preservation of the anatomical features of the stem. Three other
species were also described by Carruthers; they are: Bennettites maximus
Carr., a large stem similar to B. Saxbyanus, in the Museum of the
Geological Survey; B. portlandicus from the Lower Purbeck of the Isle of
Portland, in the collection of the Geological Society; and B. Peachianus, a
localities as well as in India, Afghanistan, and other countries, and the not
infrequent occurrence of stems assigned to Bucklandia, Yatesia,
Cylindropodium, and other genera furnish evidence of the rich development
of the Bennettitales in later Jurassic and Lower Cretaceous floras. Wieland’s
recent discovery[1126] of numerous Cycadean fronds, Williamsonia flowers,
and stems in Liassic rocks in Mexico shows that the group had already
assumed an important position in the early part of the Jurassic period.
The memoir by Carruthers[1127] on British Cycadean stems contains the
first account of the morphological features of Bennettitalean flowers based
on petrified material. In 1891 Solms-Laubach contributed an important
paper on the Bennettitean flower and several years later Lignier[1128]
contributed additional data derived from a careful study of a well preserved
strobilus[1129] from the Gault of Normandy. Wieland’s researches[1130] added
very greatly to our knowledge, particularly with regard to the morphology
of the microsporophylls. Among the earlier descriptions of the reproductive
organs of the Bennettitales is Buckland’s account[1131] of a specimen from
the Inferior Oolite of Charmouth, Dorset (fig. 560), which he referred to the
genus Podocarya (= Williamsonia Bucklandi[1132]): a thorough examination
of the type-specimen, which unfortunately cannot be found, would probably
furnish many important facts.
{ Cycadeoidea (Bennettites) Gibsoniana (Carruthers).
Cycadeoidea (Bennettites) Saxbyana (Brown).
These two species serve to illustrate the type of stem for which
Carruthers instituted the tribe Bennettiteae and the genus Bennettites.
Bennettites Gibsonianus is the most important of the five species described
by Carruthers[1133], as it was from its fertile shoots that information was first
obtained as to the nature of the ovulate strobili of the Bennettitales. B.
Saxbyanus[1134], originally described as Cycadites Saxbyanus from a
specimen found by Mr Saxby at Bonchurch in the Isle of Wight and
represented by Wealden examples from Brook Point, is chiefly interesting
for the clear preservation of the anatomical features of the stem. Three other
species were also described by Carruthers; they are: Bennettites maximus
Carr., a large stem similar to B. Saxbyanus, in the Museum of the
Geological Survey; B. portlandicus from the Lower Purbeck of the Isle of
Portland, in the collection of the Geological Society; and B. Peachianus, a
Page 426
piece of a compressed stem, in the British Museum, from the Upper
Jurassic of Helmsdale in N.E. Scotland.
Fig. 517. Cycadeoidea Gibsoniana. A, transverse section of petiole
showing vascular bundles and ramenta; B, portion of A enlarged
showing periderm and ramenta. C, tangential section of stem with
leaf-bases, ramenta (black) and two flowers, 1, 2. (A, slightly
enlarged, Manchester Collection, R, 1069; C, after Carruthers.)
Cycadeoidea (Bennettites) Gibsoniana.
This species was founded on a petrified portion of a large stem of Lower
Greensand age discovered by Mr Gibson in Luccomb Chine in the Isle of
Wight: the type-specimen is represented by pieces of the original block in
the British Museum and in one of the Museums at the Royal Gardens, Kew.
The following description is based partly on the published accounts and in
part on an examination of sections in the British Museum, the Manchester
University Museum, and in Dr Scott’s collection.
Jurassic of Helmsdale in N.E. Scotland.
Fig. 517. Cycadeoidea Gibsoniana. A, transverse section of petiole
showing vascular bundles and ramenta; B, portion of A enlarged
showing periderm and ramenta. C, tangential section of stem with
leaf-bases, ramenta (black) and two flowers, 1, 2. (A, slightly
enlarged, Manchester Collection, R, 1069; C, after Carruthers.)
Cycadeoidea (Bennettites) Gibsoniana.
This species was founded on a petrified portion of a large stem of Lower
Greensand age discovered by Mr Gibson in Luccomb Chine in the Isle of
Wight: the type-specimen is represented by pieces of the original block in
the British Museum and in one of the Museums at the Royal Gardens, Kew.
The following description is based partly on the published accounts and in
part on an examination of sections in the British Museum, the Manchester
University Museum, and in Dr Scott’s collection.
Page 427
The elliptical form of the stem and vascular cylinder as seen in transverse
section, regarded by Carruthers[1135] as a feature characteristic of the genus,
has no morphological significance and is in part at least due to compression.
In the large pith, the armour of persistent petiole-bases separated by dense
ramental scales (fig. 517, A, B), and in habit, Cycadeoidea Gibsoniana
agrees generally with the stems of many recent Cycads, but the resemblance
of the vegetative organs is in marked contrast to the differences exhibited
by the reproductive shoots. The pith consists of parenchyma with scattered
secretory ducts but no medullary vascular bundles. In the pith of
Cycadeoidea Peachiana there are patches of tissue superficially resembling
vascular strands, but these are probably bands of internal phloem like those
described by Solms-Laubach[1136] in some Italian stems. In none of the
English stems are there any clear indications of the occurrence of more than
one cambium in the stele. The secondary xylem is entirely centrifugal with
some smaller crushed elements, presumably protoxylem, at the inner edge
where the medullary rays are especially broad. The xylem is of the
manoxylic type (fig. 518, A) as in recent Cycads; though the medullary
rays, 1–2 cells broad, are rather smaller than in recent species. The tracheids
are scalariform as in Stangeria (fig. 397). As in recent Cycads there is a
broad cylinder of secondary phloem (fig. 518, B)[1137] composed of alternate
layers of thick-walled and thinner elements—sieve-tubes and parenchyma:
traces of lateral sieve-plates occur on some of the elongated elements. Each
leaf-trace arises as a single strand from the lower edge of a mesh formed by
the large inner end of a medullary ray: on emerging into the inner cortex the
trace has the form of a U-shaped strand (fig. 519, A, lt) which passes direct
to the petiole, following a steeply ascending course in Cycadeoidea
Saxbyana and almost horizontal in C. Gibsoniana. Before entering the base
of a leaf the trace breaks up into several collateral strands and these form a
simple pattern as seen in a tangential section of the leaf-bases (fig. 517, A,
C), the central bundles on the upper side forming a U-shaped involution.
There is no indication of any girdling of the foliar bundles. The
arrangement of the petiolar bundles is simpler and more Fern-like than in
the majority of existing Cycads. Each vascular bundle consists in the
petiole-base mainly of centrifugal secondary xylem and medullary-ray
tissue (fig. 519, B); a group of centripetal tracheids is usually recognisable
internal to the protoxylem: the structure is of the mesarch type with a
section, regarded by Carruthers[1135] as a feature characteristic of the genus,
has no morphological significance and is in part at least due to compression.
In the large pith, the armour of persistent petiole-bases separated by dense
ramental scales (fig. 517, A, B), and in habit, Cycadeoidea Gibsoniana
agrees generally with the stems of many recent Cycads, but the resemblance
of the vegetative organs is in marked contrast to the differences exhibited
by the reproductive shoots. The pith consists of parenchyma with scattered
secretory ducts but no medullary vascular bundles. In the pith of
Cycadeoidea Peachiana there are patches of tissue superficially resembling
vascular strands, but these are probably bands of internal phloem like those
described by Solms-Laubach[1136] in some Italian stems. In none of the
English stems are there any clear indications of the occurrence of more than
one cambium in the stele. The secondary xylem is entirely centrifugal with
some smaller crushed elements, presumably protoxylem, at the inner edge
where the medullary rays are especially broad. The xylem is of the
manoxylic type (fig. 518, A) as in recent Cycads; though the medullary
rays, 1–2 cells broad, are rather smaller than in recent species. The tracheids
are scalariform as in Stangeria (fig. 397). As in recent Cycads there is a
broad cylinder of secondary phloem (fig. 518, B)[1137] composed of alternate
layers of thick-walled and thinner elements—sieve-tubes and parenchyma:
traces of lateral sieve-plates occur on some of the elongated elements. Each
leaf-trace arises as a single strand from the lower edge of a mesh formed by
the large inner end of a medullary ray: on emerging into the inner cortex the
trace has the form of a U-shaped strand (fig. 519, A, lt) which passes direct
to the petiole, following a steeply ascending course in Cycadeoidea
Saxbyana and almost horizontal in C. Gibsoniana. Before entering the base
of a leaf the trace breaks up into several collateral strands and these form a
simple pattern as seen in a tangential section of the leaf-bases (fig. 517, A,
C), the central bundles on the upper side forming a U-shaped involution.
There is no indication of any girdling of the foliar bundles. The
arrangement of the petiolar bundles is simpler and more Fern-like than in
the majority of existing Cycads. Each vascular bundle consists in the
petiole-base mainly of centrifugal secondary xylem and medullary-ray
tissue (fig. 519, B); a group of centripetal tracheids is usually recognisable
internal to the protoxylem: the structure is of the mesarch type with a
Page 428
variable amount of centripetal xylem, and agrees generally with that in
recent Cycads.
recent Cycads.
Page 429
Page 430
Fig. 518. Cycadeoidea Gibsoniana. A, secondary xylem of stem; B,
secondary phloem and part of the cortex with secretory ducts, s.
(A, B, British Museum, 13206.)
Fig. 519. Cycadeoidea Gibsoniana. A, transverse section of the vascular
cylinder of stem, with leaf-trace, lt; c, cambium, px, protoxylem. B,
vascular bundle of petiole. (British Museum.)
The comparatively narrow cortex is composed of parenchyma with
scattered secretory sacs (fig. 518, B, s), and occasionally an elliptical
vascular strand (fig. 511) is present which is probably cauline as are the
similar strands in Cycas. The persistent petiole-bases are covered with
ramental scales which form a dense interfoliar packing: these frequently
consist of a single layer of fairly thick-walled cells or, as seen in transverse
section, of spindle-like scales one-cell thick at the edges and 2–3 cells broad
in the middle (fig. 517, B).
The presence of fertile shoots, presumably axillary, is one of the most
striking features of Bennettitean stems. The branching is monopodial and
not sympodial as in most recent Cycads. The nearest approach to the
method of branching in Cycadeoidea is afforded by some stems of
Macrozamia recently described by Chamberlain[1138]. It is not improbable
that some of the flowering branches of Cycadeoidea were branched. Solms-
secondary phloem and part of the cortex with secretory ducts, s.
(A, B, British Museum, 13206.)
Fig. 519. Cycadeoidea Gibsoniana. A, transverse section of the vascular
cylinder of stem, with leaf-trace, lt; c, cambium, px, protoxylem. B,
vascular bundle of petiole. (British Museum.)
The comparatively narrow cortex is composed of parenchyma with
scattered secretory sacs (fig. 518, B, s), and occasionally an elliptical
vascular strand (fig. 511) is present which is probably cauline as are the
similar strands in Cycas. The persistent petiole-bases are covered with
ramental scales which form a dense interfoliar packing: these frequently
consist of a single layer of fairly thick-walled cells or, as seen in transverse
section, of spindle-like scales one-cell thick at the edges and 2–3 cells broad
in the middle (fig. 517, B).
The presence of fertile shoots, presumably axillary, is one of the most
striking features of Bennettitean stems. The branching is monopodial and
not sympodial as in most recent Cycads. The nearest approach to the
method of branching in Cycadeoidea is afforded by some stems of
Macrozamia recently described by Chamberlain[1138]. It is not improbable
that some of the flowering branches of Cycadeoidea were branched. Solms-
Page 431
Laubach[1139] states that he observed certain
characters in the secondary axes of Cycadeoidea
Gibsoniana which led him to suspect that there
may have been fascicled systems of fertile
shoots emerging in a body or in close proximity
to one another between the leaf-bases of the
stem. An example of a branched flowering shoot
is described in Williamsonia scotica[1140]. A Fig. 520. Cycadeoidea
fertile shoot agrees in structure with the main Gibsoniana. Ground-
axis and Scott[1141] states that the phloem is tissue of bract. (British
particularly well developed, a feature by no Museum. 41388.)
means unusual in fertile branches. These lateral
shoots (fig. 514) bear numerous linear bracts each with three collateral
vascular bundles, and ground-tissue composed of thick-walled cells
characterised by scalariform pitting (fig. 520): secretory sacs are abundant.
The hypodermal stereome is especially developed on the inner face of the
bracts. The apex of a lateral shoot has the form of a rounded cushion (figs.
514; 521, A, C) similar to the receptacle of many Composites, and on this
are borne the sporophylls. It is characteristic of Cycadeoidea that the
flowers project very slightly beyond the surface of the stem and the
peduncles are not exposed except in tangential sections through the leaf-
base armour (fig. 517, C, 1, 2). On the fall of the flower or ripe ‘fruit,’
which is effected by an absciss-layer (figs. 521, C, a; 522, a), a cup-like
scar is left on the stem (cf. fig. 534). This method of flower-production
suggests comparison, mutatis mutandis, with the phenomenon of cauliflory
in certain recent Flowering plants; it is one of the distinguishing features
between Cycadeoidea and stems bearing longer fertile shoots with flowers
of the Williamsonia type.
characters in the secondary axes of Cycadeoidea
Gibsoniana which led him to suspect that there
may have been fascicled systems of fertile
shoots emerging in a body or in close proximity
to one another between the leaf-bases of the
stem. An example of a branched flowering shoot
is described in Williamsonia scotica[1140]. A Fig. 520. Cycadeoidea
fertile shoot agrees in structure with the main Gibsoniana. Ground-
axis and Scott[1141] states that the phloem is tissue of bract. (British
particularly well developed, a feature by no Museum. 41388.)
means unusual in fertile branches. These lateral
shoots (fig. 514) bear numerous linear bracts each with three collateral
vascular bundles, and ground-tissue composed of thick-walled cells
characterised by scalariform pitting (fig. 520): secretory sacs are abundant.
The hypodermal stereome is especially developed on the inner face of the
bracts. The apex of a lateral shoot has the form of a rounded cushion (figs.
514; 521, A, C) similar to the receptacle of many Composites, and on this
are borne the sporophylls. It is characteristic of Cycadeoidea that the
flowers project very slightly beyond the surface of the stem and the
peduncles are not exposed except in tangential sections through the leaf-
base armour (fig. 517, C, 1, 2). On the fall of the flower or ripe ‘fruit,’
which is effected by an absciss-layer (figs. 521, C, a; 522, a), a cup-like
scar is left on the stem (cf. fig. 534). This method of flower-production
suggests comparison, mutatis mutandis, with the phenomenon of cauliflory
in certain recent Flowering plants; it is one of the distinguishing features
between Cycadeoidea and stems bearing longer fertile shoots with flowers
of the Williamsonia type.
Page 432
Fig. 521. Cycadeoidea (Bennettites) Gibsoniana. A, C, longitudinal
sections; a, absciss-layer; b, bracts; pr, ‘pericarp’; s, scales, sterile
and fertile. B, transverse section of female flower; i, interseminal
scales; m, megasporophylls. D, transverse section of seed showing
the testa, t, separated by a space, sp, from the embryo. E, embryo;
r, radicle. (A, B, D, E, after Solms-Laubach; C, section in the
British Museum.)
sections; a, absciss-layer; b, bracts; pr, ‘pericarp’; s, scales, sterile
and fertile. B, transverse section of female flower; i, interseminal
scales; m, megasporophylls. D, transverse section of seed showing
the testa, t, separated by a space, sp, from the embryo. E, embryo;
r, radicle. (A, B, D, E, after Solms-Laubach; C, section in the
British Museum.)
Page 433
Fig. 517, C, shows a tangentially cut surface of a portion of the stem of
Cycadeoidea Gibsoniana with two axillary fertile shoots; one, 1, is cut
across below the receptacle and shows the axis surrounded by bracts while
the other, 2, is seen at a higher level, above the receptacle, where the section
has exposed the numerous sporophylls. The rounded surface of the
receptacle is covered with a dense cluster of long slender appendages, seed-
stalks and interseminal scales, the latter being much more numerous than
the former (fig. 521, A, B). These organs are believed to be homologous
foliar structures, the seed-stalks being megasporophylls and the
interseminal scales abortive or potential sporophylls (see also figs. 562,
563). Fig. 514 shows the form of a single flower from an American stem
closely allied to Cycadeoidea Gibsoniana.
Fig. 522. Cycadeoidea Gibsoniana. Longitudinal section of flower
showing half the receptacle with part of the absciss-layer, a. (British
Museum.)
Cycadeoidea Gibsoniana with two axillary fertile shoots; one, 1, is cut
across below the receptacle and shows the axis surrounded by bracts while
the other, 2, is seen at a higher level, above the receptacle, where the section
has exposed the numerous sporophylls. The rounded surface of the
receptacle is covered with a dense cluster of long slender appendages, seed-
stalks and interseminal scales, the latter being much more numerous than
the former (fig. 521, A, B). These organs are believed to be homologous
foliar structures, the seed-stalks being megasporophylls and the
interseminal scales abortive or potential sporophylls (see also figs. 562,
563). Fig. 514 shows the form of a single flower from an American stem
closely allied to Cycadeoidea Gibsoniana.
Fig. 522. Cycadeoidea Gibsoniana. Longitudinal section of flower
showing half the receptacle with part of the absciss-layer, a. (British
Museum.)
Page 434
The megasporophylls are more or less
polygonal in transverse section: there is a
central concentric vascular strand surrounded by
a thick cortex (fig. 527): at its upper end the
sporophyll bears a single orthotropous seed
containing a dicotyledonous embryo (figs. 521,
D, E; 523). The vascular strand pierces the base
of the testa and expands to form a shallow cup
of tracheal tissue in the chalaza; there are no
bundles in the single integument. The testa (fig.
521, D, t) consists of three regions, a median
layer of rather large rectangular or palisade-cells
with an inner and outer tissue composed of
much smaller cells. The testa is prolonged
distally as a slender cylindrical column or
micropylar tube at the base of which it becomes Fig. 523. Cycadeoidea
broader owing to the increase in breadth of the Gibsoniana. Seed with
middle or palisade layer. A nucellar beak embryo. (British
projects as a cone into the base of the Museum, 41388.)
micropylar tube. No pollen-chamber has been found. It is noteworthy that
the micropyle is closed in the ripe seeds. Internal to the testa there is a
crushed membrane separated from the embryo by a space (fig. 521, D, sp):
this is the remains of the nucellus and, as Solms-Laubach points out, there
is no proof that any endosperm was present in the ripe seeds[1142]. The
embryo consists of a short axis, the conical radicle and the very short apex
of the epicotyl, also two equal cotyledons each with a few vascular bundles
(fig. 521, D). The long interseminal scales, as seen in transverse section in
the lower part of a flower between the sporophylls, appear as compressed
polygonal organs (fig. 521, B, i) with an axial vascular strand surrounded
by parenchyma and limited by a strong epidermis; they pass up between the
seed-stalks, m, and in the distal end become considerably enlarged (figs.
514, 515), gradually expanding to form a truncate or slightly pyramidal
apex (figs. 553, 563). The swollen peltate apices of adjacent scales form a
continuous covering to the flower interrupted, except in the lower sterile
part of the flower, by symmetrically disposed cylindrical micropylar tubes
(fig. 515). The peripheral interseminal scales form a homogeneous
parenchymatous tissue which springs from below the edge of the receptacle
polygonal in transverse section: there is a
central concentric vascular strand surrounded by
a thick cortex (fig. 527): at its upper end the
sporophyll bears a single orthotropous seed
containing a dicotyledonous embryo (figs. 521,
D, E; 523). The vascular strand pierces the base
of the testa and expands to form a shallow cup
of tracheal tissue in the chalaza; there are no
bundles in the single integument. The testa (fig.
521, D, t) consists of three regions, a median
layer of rather large rectangular or palisade-cells
with an inner and outer tissue composed of
much smaller cells. The testa is prolonged
distally as a slender cylindrical column or
micropylar tube at the base of which it becomes Fig. 523. Cycadeoidea
broader owing to the increase in breadth of the Gibsoniana. Seed with
middle or palisade layer. A nucellar beak embryo. (British
projects as a cone into the base of the Museum, 41388.)
micropylar tube. No pollen-chamber has been found. It is noteworthy that
the micropyle is closed in the ripe seeds. Internal to the testa there is a
crushed membrane separated from the embryo by a space (fig. 521, D, sp):
this is the remains of the nucellus and, as Solms-Laubach points out, there
is no proof that any endosperm was present in the ripe seeds[1142]. The
embryo consists of a short axis, the conical radicle and the very short apex
of the epicotyl, also two equal cotyledons each with a few vascular bundles
(fig. 521, D). The long interseminal scales, as seen in transverse section in
the lower part of a flower between the sporophylls, appear as compressed
polygonal organs (fig. 521, B, i) with an axial vascular strand surrounded
by parenchyma and limited by a strong epidermis; they pass up between the
seed-stalks, m, and in the distal end become considerably enlarged (figs.
514, 515), gradually expanding to form a truncate or slightly pyramidal
apex (figs. 553, 563). The swollen peltate apices of adjacent scales form a
continuous covering to the flower interrupted, except in the lower sterile
part of the flower, by symmetrically disposed cylindrical micropylar tubes
(fig. 515). The peripheral interseminal scales form a homogeneous
parenchymatous tissue which springs from below the edge of the receptacle
Page 435
(fig. 521, A, B, pr) and the individuality of the scales composing this
‘pericarp’ is indicated by occasional invaginations of the epidermal layer
which marks the boundary of the polygonal areas. The structure of the
megasporophylls and scales is more fully described in the case of
Cycadeoidea (Bennettites) Morierei[1143].
The flowers of Cycadeoidea Gibsoniana appear to be unisexual and
ovulate: in view of the discovery by Wieland of numerous bisexual fertile
shoots on American species of Cycadeoidea it would be reasonable to
regard the apparently unisexual flowers of the English species as originally
bisexual but preserved at a stage subsequent to the loss, by abscission, of
the disc of microsporophylls. Fig. 514 shows a flower of an American
Cycadeoidea practically identical with those of C. Gibsoniana, but the
remains of the staminate disc are clearly seen at d below the swollen apex
of the flowering axis. In the photograph of half of the same region in C.
Gibsoniana reproduced in fig. 522 there is no indication of any similar trace
of a whorl of microsporophylls. Admitting the fact that a shrivelled remnant
of the persistent base of a whorl of microsporophylls might easily escape
observation, it is difficult to believe that any fertile leaves ever existed in
the flower represented in figs. 521, 522. It is equally difficult to regard the
specimen represented in fig. 561 as other than a true unisexual (ovulate)
flower.
Cycadeoidea (Bennettites) Morierei (Saporta and Marion).
The name Bennettites was adopted by Lignier for this species which was
founded on a detached flower from the Gault[1144] of Vaches-Noires,
Normandy. It was first described by Morière[1145], then by Saporta and
Marion[1146], who named it Williamsonia Morierei, and it has since been
thoroughly investigated by Lignier[1147]. There is no evidence as to the
nature of the parent-stem though Morière suggested a possible connexion
with Zamia Brongniarti Mor. (figured by Saporta[1148] as Fittonia
Brongniarti) from the same locality. There can be no reasonable doubt that
Bennettites Morierei was borne on a lateral branch of a stem of the
Cycadeoidea type: it is constructed on essentially the same plan as the
flowers of Cycadeoidea (Bennettites) Gibsoniana, and in both cases there is
no indication of the presence of microsporophylls. The type-specimen is 5·5
cm. long and 3·5 cm. broad, ovoid, and characterised by a depressed
‘pericarp’ is indicated by occasional invaginations of the epidermal layer
which marks the boundary of the polygonal areas. The structure of the
megasporophylls and scales is more fully described in the case of
Cycadeoidea (Bennettites) Morierei[1143].
The flowers of Cycadeoidea Gibsoniana appear to be unisexual and
ovulate: in view of the discovery by Wieland of numerous bisexual fertile
shoots on American species of Cycadeoidea it would be reasonable to
regard the apparently unisexual flowers of the English species as originally
bisexual but preserved at a stage subsequent to the loss, by abscission, of
the disc of microsporophylls. Fig. 514 shows a flower of an American
Cycadeoidea practically identical with those of C. Gibsoniana, but the
remains of the staminate disc are clearly seen at d below the swollen apex
of the flowering axis. In the photograph of half of the same region in C.
Gibsoniana reproduced in fig. 522 there is no indication of any similar trace
of a whorl of microsporophylls. Admitting the fact that a shrivelled remnant
of the persistent base of a whorl of microsporophylls might easily escape
observation, it is difficult to believe that any fertile leaves ever existed in
the flower represented in figs. 521, 522. It is equally difficult to regard the
specimen represented in fig. 561 as other than a true unisexual (ovulate)
flower.
Cycadeoidea (Bennettites) Morierei (Saporta and Marion).
The name Bennettites was adopted by Lignier for this species which was
founded on a detached flower from the Gault[1144] of Vaches-Noires,
Normandy. It was first described by Morière[1145], then by Saporta and
Marion[1146], who named it Williamsonia Morierei, and it has since been
thoroughly investigated by Lignier[1147]. There is no evidence as to the
nature of the parent-stem though Morière suggested a possible connexion
with Zamia Brongniarti Mor. (figured by Saporta[1148] as Fittonia
Brongniarti) from the same locality. There can be no reasonable doubt that
Bennettites Morierei was borne on a lateral branch of a stem of the
Cycadeoidea type: it is constructed on essentially the same plan as the
flowers of Cycadeoidea (Bennettites) Gibsoniana, and in both cases there is
no indication of the presence of microsporophylls. The type-specimen is 5·5
cm. long and 3·5 cm. broad, ovoid, and characterised by a depressed
Page 436
cushion-like receptacle as in Cycadeoidea Gibsoniana. The enveloping
bracts with their ramental scales agree generally in structure with those of
the English species and, except as regards the ramenta, with Williamsonia
scotica: numerous stomata occur on the lower surface; the ground-tissue
consists of thick-walled parenchyma and the narrow pit-canals simulate the
scalariform bands in Cycadeoidea Gibsoniana (cf. fig. 520). The pitted
sclerous cells in the bracts of W. scotica are of the same type. There is an
anastomosing system of secretory canals, also several vascular bundles like
those in C. Gibsoniana but more numerous; the latter are composed of a
group of phloem-elements abutting externally on fibres, a well-defined
cambium, and radially disposed scalariform tracheids: internal to the
protoxylem is a group of elements considered by Lignier to be centripetal
xylem. From the branching and slightly divergent course of the bundles in
the upper part of the bracts Lignier concluded that these organs represent
the basal portions of leaves originally provided with a terminal limb. It may
be that the small lateral appendages to some of the bracts of Williamsonia
scotica (fig. 561, l) afford support to this view.
Megasporophylls (seed-stalks and seeds). These organs, 3–4·5 cm. long
and approximately 1·5 mm. in diameter, are in most cases imperfectly
preserved. In transverse section and at a level of 1 cm. above the receptacle
a stalk bearing an atrophied seed shows the following features: an epidermis
with very thick internal walls encloses a parenchymatous ground-tissue
with an axial conducting strand. At a higher level the epidermal cells have
walls of uniform thickness, and a hypodermal layer of cells with coloured
contents is differentiated from the ground-tissue (fig. 524, D, ac). As the
seed-base is approached the epidermal cells tend to separate from one
another and divide longitudinally, the compact epidermal layer being
replaced by an envelope of tubular, dissociated, cells (fig. 524, D, Et).
Similar tubular elements occur in the seed-stalks of Cycadeoidea
Gibsoniana. A fully developed seed-stalk bearing a complete seed cut
across in the middle region shows the following features: a concentric
vascular strand surrounded by thin-walled parenchyma and the coloured
hypodermal layer (fig. 524, D, ac), the whole being enclosed in the tubular
envelope of epidermal origin (Et) which is more strongly developed than in
the stalks of imperfect seeds: there may be as many as 10–12 tubular cells
on one radius. When traced downwards towards the receptacle the tubular
envelope decreases in breadth, though the cells become more numerous and
bracts with their ramental scales agree generally in structure with those of
the English species and, except as regards the ramenta, with Williamsonia
scotica: numerous stomata occur on the lower surface; the ground-tissue
consists of thick-walled parenchyma and the narrow pit-canals simulate the
scalariform bands in Cycadeoidea Gibsoniana (cf. fig. 520). The pitted
sclerous cells in the bracts of W. scotica are of the same type. There is an
anastomosing system of secretory canals, also several vascular bundles like
those in C. Gibsoniana but more numerous; the latter are composed of a
group of phloem-elements abutting externally on fibres, a well-defined
cambium, and radially disposed scalariform tracheids: internal to the
protoxylem is a group of elements considered by Lignier to be centripetal
xylem. From the branching and slightly divergent course of the bundles in
the upper part of the bracts Lignier concluded that these organs represent
the basal portions of leaves originally provided with a terminal limb. It may
be that the small lateral appendages to some of the bracts of Williamsonia
scotica (fig. 561, l) afford support to this view.
Megasporophylls (seed-stalks and seeds). These organs, 3–4·5 cm. long
and approximately 1·5 mm. in diameter, are in most cases imperfectly
preserved. In transverse section and at a level of 1 cm. above the receptacle
a stalk bearing an atrophied seed shows the following features: an epidermis
with very thick internal walls encloses a parenchymatous ground-tissue
with an axial conducting strand. At a higher level the epidermal cells have
walls of uniform thickness, and a hypodermal layer of cells with coloured
contents is differentiated from the ground-tissue (fig. 524, D, ac). As the
seed-base is approached the epidermal cells tend to separate from one
another and divide longitudinally, the compact epidermal layer being
replaced by an envelope of tubular, dissociated, cells (fig. 524, D, Et).
Similar tubular elements occur in the seed-stalks of Cycadeoidea
Gibsoniana. A fully developed seed-stalk bearing a complete seed cut
across in the middle region shows the following features: a concentric
vascular strand surrounded by thin-walled parenchyma and the coloured
hypodermal layer (fig. 524, D, ac), the whole being enclosed in the tubular
envelope of epidermal origin (Et) which is more strongly developed than in
the stalks of imperfect seeds: there may be as many as 10–12 tubular cells
on one radius. When traced downwards towards the receptacle the tubular
envelope decreases in breadth, though the cells become more numerous and
Page 437
smaller, until in the immediate neighbourhood of the receptacle the tubular
tissue is transformed into a compact parenchyma of large cells each of
which corresponds to a group of tubes formed by the septation of the cells.
Traced upwards this thin-walled parenchyma gradually passes into thick-
walled tubes, and near the seed-base the tubular envelope is reduced to two
layers, an inner consisting of relatively small cells with sinuous radial walls
(the folded layer of Lignier) and an outer tubular layer. Lignier describes an
interesting abnormality, a bifid seed-stalk enclosed in a common epidermis
which he compares with the occasional branching of the seed-stalks of
Ginkgo biloba.
tissue is transformed into a compact parenchyma of large cells each of
which corresponds to a group of tubes formed by the septation of the cells.
Traced upwards this thin-walled parenchyma gradually passes into thick-
walled tubes, and near the seed-base the tubular envelope is reduced to two
layers, an inner consisting of relatively small cells with sinuous radial walls
(the folded layer of Lignier) and an outer tubular layer. Lignier describes an
interesting abnormality, a bifid seed-stalk enclosed in a common epidermis
which he compares with the occasional branching of the seed-stalks of
Ginkgo biloba.
Page 438
Fig. 524. Cycadeoidea (Bennettites) Morierei.
A. Transverse section of the micropylar tube containing the apex of the
nucellus; Ei, inner epidermis; Tf, ground-tissue; e, outer epidermis
with the thickening of the walls shown in a few of the cells.
B. Transverse section of the upper part of the micropylar tube;
lettering as in fig. A.
C. Transverse section at the level of the wings formed by the fibrous
layer and corresponding to the angles of the seed, approximately at
the level cp in fig. 525; cn, nucellar cavity; Ei, inner epidermis of
seed-coat; cf, fibrous layer of wings, f, which extend across the
fleshy layer, tch, to the radial layer ar (cf. fig. 525); at, tubular
layer; Ee, epidermis of adjacent scale detached from the other
tissues, ase, along the line of fracture d; EE, epidermis of two
adjacent scales.
D. Transverse section of peduncle; tr, tracheids; ac, coloured
subepidermal layer; Et, tubular epidermis, double in places; EE,
epidermis formed from neighbouring scales. (From Prof. Lignier’s
drawings; A, B, D, × 118; C, × 90.)
Seeds. The seeds (figs. 525, 526), 6–7 × 2·5–3 mm., are tetragonal or
pentagonal in the upper half (fig. 527, 1, 2), the angles being formed by
thick but not very prominent wings of tissue (fig. 524, C, cf); they are
orthotropous and have a single integument (figs. 525, 526). The tubular
A. Transverse section of the micropylar tube containing the apex of the
nucellus; Ei, inner epidermis; Tf, ground-tissue; e, outer epidermis
with the thickening of the walls shown in a few of the cells.
B. Transverse section of the upper part of the micropylar tube;
lettering as in fig. A.
C. Transverse section at the level of the wings formed by the fibrous
layer and corresponding to the angles of the seed, approximately at
the level cp in fig. 525; cn, nucellar cavity; Ei, inner epidermis of
seed-coat; cf, fibrous layer of wings, f, which extend across the
fleshy layer, tch, to the radial layer ar (cf. fig. 525); at, tubular
layer; Ee, epidermis of adjacent scale detached from the other
tissues, ase, along the line of fracture d; EE, epidermis of two
adjacent scales.
D. Transverse section of peduncle; tr, tracheids; ac, coloured
subepidermal layer; Et, tubular epidermis, double in places; EE,
epidermis formed from neighbouring scales. (From Prof. Lignier’s
drawings; A, B, D, × 118; C, × 90.)
Seeds. The seeds (figs. 525, 526), 6–7 × 2·5–3 mm., are tetragonal or
pentagonal in the upper half (fig. 527, 1, 2), the angles being formed by
thick but not very prominent wings of tissue (fig. 524, C, cf); they are
orthotropous and have a single integument (figs. 525, 526). The tubular
Page 439
layer forming the outer portion of a seed-stalk near the seed-base is
prolonged over the surface of the testa as a discontinuous covering in the
form of isolated or small groups of tubes, giving a striated appearance to the
seeds. This layer though apparently a part of the seed is derived from the
neighbouring interseminal scales of which it is the epidermal layer; it
consists of elongated cells and scattered stomata[1149]. The folded layer
persists only in the lower part of the seed, being replaced by a layer of
radially extended cells (radial layer; ar, figs. 524, C; 525, ar; 527, c) in the
upper region of the seed. In the micropylar region both the tubular and
folded layers undergo further change; the external, tubular, layer forms a
kind of epidermis (at, figs. 524, 525), the subepidermal layer, consisting of
the radially elongated cells (figs. 524, 525, ar; 527, c). The superficial layer
assumes a different aspect in the micropylar region, its cells being thicker
walled, as are also those of the subepidermal layer (fig. 524, A and B). The
micropylar canal (figs. 524, 525, cm) is cylindrical in the lower part but at
the apex is reduced to a long and narrow slit bounded by an internal
epidermis of radially stretched cells which in the lower portion of the tube
are thinner walled and isodiametric. The rest of the testa is differentiated
into two regions; an outer fleshy region immediately internal to the folded
(or radial) layer and an inner fibrous region next the nucellus, which is one-
layer broad between the wings but opposite the wings it extends radially
outwards across the fleshy tissue to the radial layer (figs. 524, C; 525; 527):
in the winged portion of the seed this tissue forms the inner fibrous portion
of the wings but in the lower part of the seed below the wings it forms a
single layer of uniform breadth finally spreading out as a basal cup in the
chalazal region where it is pierced by the vascular strand. The fleshy
portion of the testa forms one layer in the proximal part of the seed and
becomes several layers wide between the fibrous wings in the upper part.
This fleshy tissue appears to be derived from the coloured, subepidermal,
layer of the seed-stalk, while the internal parenchyma is regarded by
Lignier as the equivalent of the fibrous layer of the testa. In the micropylar
tube the fibrous layers are replaced by 2–3 layers of sclerous cells (fig. 524,
A, B). The testa has no vascular supply: the concentric strand of the seed-
stalk passes through the fibrous tissue at the base of the seed and reaches
the base of the nucellus (fig. 525). The nucellar apex extends into the lower
part of the micropyle (fig. 525, n), and in some cases Lignier noticed an
axial canal formed by the breaking-down of the cells which abutted below
prolonged over the surface of the testa as a discontinuous covering in the
form of isolated or small groups of tubes, giving a striated appearance to the
seeds. This layer though apparently a part of the seed is derived from the
neighbouring interseminal scales of which it is the epidermal layer; it
consists of elongated cells and scattered stomata[1149]. The folded layer
persists only in the lower part of the seed, being replaced by a layer of
radially extended cells (radial layer; ar, figs. 524, C; 525, ar; 527, c) in the
upper region of the seed. In the micropylar region both the tubular and
folded layers undergo further change; the external, tubular, layer forms a
kind of epidermis (at, figs. 524, 525), the subepidermal layer, consisting of
the radially elongated cells (figs. 524, 525, ar; 527, c). The superficial layer
assumes a different aspect in the micropylar region, its cells being thicker
walled, as are also those of the subepidermal layer (fig. 524, A and B). The
micropylar canal (figs. 524, 525, cm) is cylindrical in the lower part but at
the apex is reduced to a long and narrow slit bounded by an internal
epidermis of radially stretched cells which in the lower portion of the tube
are thinner walled and isodiametric. The rest of the testa is differentiated
into two regions; an outer fleshy region immediately internal to the folded
(or radial) layer and an inner fibrous region next the nucellus, which is one-
layer broad between the wings but opposite the wings it extends radially
outwards across the fleshy tissue to the radial layer (figs. 524, C; 525; 527):
in the winged portion of the seed this tissue forms the inner fibrous portion
of the wings but in the lower part of the seed below the wings it forms a
single layer of uniform breadth finally spreading out as a basal cup in the
chalazal region where it is pierced by the vascular strand. The fleshy
portion of the testa forms one layer in the proximal part of the seed and
becomes several layers wide between the fibrous wings in the upper part.
This fleshy tissue appears to be derived from the coloured, subepidermal,
layer of the seed-stalk, while the internal parenchyma is regarded by
Lignier as the equivalent of the fibrous layer of the testa. In the micropylar
tube the fibrous layers are replaced by 2–3 layers of sclerous cells (fig. 524,
A, B). The testa has no vascular supply: the concentric strand of the seed-
stalk passes through the fibrous tissue at the base of the seed and reaches
the base of the nucellus (fig. 525). The nucellar apex extends into the lower
part of the micropyle (fig. 525, n), and in some cases Lignier noticed an
axial canal formed by the breaking-down of the cells which abutted below
Page 440
on a cavity above the embryo, probably the remains of a pollen-chamber
(figs. 525, 527). No microspores have been found. Two dark spots shown at
co, fig. 525, may represent archegonia but this is doubtful, especially as the
seed contains a well-developed embryo. The nucellus is free from the testa
only in the apical region and a dicotyledonous embryo occupies the interior
without any trace of endosperm. Lignier points out that in some seeds
containing embryos the nucellar beak is not completely perforated: in this
fact and in the absence of microspores in the micropylar canals he is
inclined to see evidence of parthenogenesis[1150].
(figs. 525, 527). No microspores have been found. Two dark spots shown at
co, fig. 525, may represent archegonia but this is doubtful, especially as the
seed contains a well-developed embryo. The nucellus is free from the testa
only in the apical region and a dicotyledonous embryo occupies the interior
without any trace of endosperm. Lignier points out that in some seeds
containing embryos the nucellar beak is not completely perforated: in this
fact and in the absence of microspores in the micropylar canals he is
inclined to see evidence of parthenogenesis[1150].
Page 441
Fig. 525. Cycadeoidea (Bennettites) Morierei. Section of a seed and
adjacent interseminal scales. tm, micropylar tube; n, nucellar beak
in the micropylar canal, cm; cp, pollen-chamber; co, archegonia
(?); em, position of the embryo; ch, chalaza; dn, remains of the
nucellus; af, fibrous layer passing below into the shell, cq, and the
peduncle, Tf; tch, fleshy layer; ar, radial and tubular layers
represented in the peduncle by the tubular envelope at; Ec, swollen
ends of the interseminal scales. (From a drawing kindly supplied
by Prof. Lignier; × 10.)
adjacent interseminal scales. tm, micropylar tube; n, nucellar beak
in the micropylar canal, cm; cp, pollen-chamber; co, archegonia
(?); em, position of the embryo; ch, chalaza; dn, remains of the
nucellus; af, fibrous layer passing below into the shell, cq, and the
peduncle, Tf; tch, fleshy layer; ar, radial and tubular layers
represented in the peduncle by the tubular envelope at; Ec, swollen
ends of the interseminal scales. (From a drawing kindly supplied
by Prof. Lignier; × 10.)
Page 442
Fig. 526. Cycadeoidea (Bennettites) Morierei. Longitudinal section of a
seed and interseminal scales. (From a photograph supplied by Prof.
Lignier.)
In several respects the seeds of Cycadeoidea agree with those of Gnetum:
reference should be made to the account of the seed of Gnetum africanum
in Chapter lii. and to the papers referred to in the footnote[1151].
Interseminal scales. The young seed-stalks agree very closely with the
interseminal scales: each seed-stalk is surrounded by 5–6 scales (fig. 527)
as in other Bennettitean flowers (fig. 564). For the greater part of their
length the interseminal scales are compressed, but above the seeds, where
seed and interseminal scales. (From a photograph supplied by Prof.
Lignier.)
In several respects the seeds of Cycadeoidea agree with those of Gnetum:
reference should be made to the account of the seed of Gnetum africanum
in Chapter lii. and to the papers referred to in the footnote[1151].
Interseminal scales. The young seed-stalks agree very closely with the
interseminal scales: each seed-stalk is surrounded by 5–6 scales (fig. 527)
as in other Bennettitean flowers (fig. 564). For the greater part of their
length the interseminal scales are compressed, but above the seeds, where
Page 443
they are free from pressure (fig. 526), they become much thicker and form a
covering (‘pericarp’) as in Cycadeoidea Gibsoniana. In its upper region an
interseminal scale consists of an epidermis with strongly thickened inner
walls, hypodermal thick-walled cells and parenchymatous ground-tissue
with a single axial bundle. In the lower part the scale is more flattened and
the thick-walled hypoderm is replaced by thin-walled parenchyma. Some of
the scales at the periphery of the receptacle where there are no seed-stalks
are broader and may have six vascular bundles; this, Lignier suggested,
might be regarded as evidence of the reduction of the interseminal scales
from leaves possessing a terminal limb; but a further examination of scales
at the periphery of the flower led him to the conclusion that the distal
swelling of the scales is solely due to the hypertrophy of conjunctive tissue
and is not the result of the modification of a reduced limb[1152]. The
morphological value of the interseminal scales and seed-stalks has not been
definitely settled, though the probability is that they are homologous organs
and foliar. Solms-Laubach[1153] suggested that both may be axial, the seed-
stalks representing axes ending in a flower reduced to a single ovule; or, he
adds, the seed-stalks may just as well be carpels, though in that case we
should have the unusual phenomenon of terminal seeds. The interseminal
scales may be aborted seed-stalks crushed between the latter; or if the seed-
stalks are axes, the scales may be foliar. He is inclined to see in the scales
the bracts and prophylls of seed-stalks to which must be added such
bracteoles, preceding the seed or flower, as may happen to spring from the
seed-stalks. Pearson[1154], on the assumption that the seed-stalks are axial
structures, institutes a comparison between Welwitschia and Bennettites and
regards each flower of Welwitschia as a much reduced Bennettitean
strobilus. Lignier believes the interseminal scales to be leaves borne on the
swollen apex (receptacle) of an axis of the second order, while the seed-
stalks are fertile leaves of a unifoliar bud of the third order possibly axillary
though not necessarily so to the interseminal scales. My own view,
influenced by the examination of the immature flower of Williamsonia
scotica, is that the seed-stalks (megasporophylls) and scales are
homologous, the former being sporophylls and the latter sterile foliage
leaves, the whole flower, as Wettstein[1155] says, consisting of a conical axis
bearing numerous fertile and sterile carpels enclosed by a perianth of bracts.
Worsdell[1156], who shares Čelakovsky’s opinion that sporophylls were
originally radially symmetrical organs bearing a terminal sporangium,
covering (‘pericarp’) as in Cycadeoidea Gibsoniana. In its upper region an
interseminal scale consists of an epidermis with strongly thickened inner
walls, hypodermal thick-walled cells and parenchymatous ground-tissue
with a single axial bundle. In the lower part the scale is more flattened and
the thick-walled hypoderm is replaced by thin-walled parenchyma. Some of
the scales at the periphery of the receptacle where there are no seed-stalks
are broader and may have six vascular bundles; this, Lignier suggested,
might be regarded as evidence of the reduction of the interseminal scales
from leaves possessing a terminal limb; but a further examination of scales
at the periphery of the flower led him to the conclusion that the distal
swelling of the scales is solely due to the hypertrophy of conjunctive tissue
and is not the result of the modification of a reduced limb[1152]. The
morphological value of the interseminal scales and seed-stalks has not been
definitely settled, though the probability is that they are homologous organs
and foliar. Solms-Laubach[1153] suggested that both may be axial, the seed-
stalks representing axes ending in a flower reduced to a single ovule; or, he
adds, the seed-stalks may just as well be carpels, though in that case we
should have the unusual phenomenon of terminal seeds. The interseminal
scales may be aborted seed-stalks crushed between the latter; or if the seed-
stalks are axes, the scales may be foliar. He is inclined to see in the scales
the bracts and prophylls of seed-stalks to which must be added such
bracteoles, preceding the seed or flower, as may happen to spring from the
seed-stalks. Pearson[1154], on the assumption that the seed-stalks are axial
structures, institutes a comparison between Welwitschia and Bennettites and
regards each flower of Welwitschia as a much reduced Bennettitean
strobilus. Lignier believes the interseminal scales to be leaves borne on the
swollen apex (receptacle) of an axis of the second order, while the seed-
stalks are fertile leaves of a unifoliar bud of the third order possibly axillary
though not necessarily so to the interseminal scales. My own view,
influenced by the examination of the immature flower of Williamsonia
scotica, is that the seed-stalks (megasporophylls) and scales are
homologous, the former being sporophylls and the latter sterile foliage
leaves, the whole flower, as Wettstein[1155] says, consisting of a conical axis
bearing numerous fertile and sterile carpels enclosed by a perianth of bracts.
Worsdell[1156], who shares Čelakovsky’s opinion that sporophylls were
originally radially symmetrical organs bearing a terminal sporangium,
Page 444
regards the flowers of Cycadeoidea Gibsoniana and other species as more
primitive than those of recent Cycads: he does not see any justification for
the view that the Bennettitalean flowers are in advance of those of existing
Cycadean plants as regards a supposed tendency towards the
Angiospermous type. He maintains that Bennettites ‘shows absolutely no
indication of such an advanced structure in its essential organs, the
sporophylls, which remain primitively radial in structure, bearing the ovules
in a terminal position.’
Fig. 527. Cycadeoidea Morierei. Transverse section of interseminal
scales and seeds near the apex of the latter; seeds 1 and 2 show the
pollen-chamber, a; the fibrous layer, b, forming wings and extending
across the fleshy tissue; c, the radial layer; seeds 3 and 4 are aborted.
(After Lignier.)
The letters a, b, c, in this figure correspond to cp, cf, and ar in figs. 525,
526.
Cycadeoidea dacotensis (McBride).
McBride[1157] first described this Lower Cretaceous species from the
Black Hills of South Dakota as Bennettites dacotensis, the generic name
Cycadeoidea being adopted by Ward[1158] who distinguished some of
McBride’s specimens as Cycadeoidea McBridei. The stem is elliptical in
section, 32 cm. long and 45 cm. in girth: owing to the partial decay of the
petiole-bases the ramental reticulum forms a prominent feature. Numerous
flowers, all of which are approximately at the same stage of development,
primitive than those of recent Cycads: he does not see any justification for
the view that the Bennettitalean flowers are in advance of those of existing
Cycadean plants as regards a supposed tendency towards the
Angiospermous type. He maintains that Bennettites ‘shows absolutely no
indication of such an advanced structure in its essential organs, the
sporophylls, which remain primitively radial in structure, bearing the ovules
in a terminal position.’
Fig. 527. Cycadeoidea Morierei. Transverse section of interseminal
scales and seeds near the apex of the latter; seeds 1 and 2 show the
pollen-chamber, a; the fibrous layer, b, forming wings and extending
across the fleshy tissue; c, the radial layer; seeds 3 and 4 are aborted.
(After Lignier.)
The letters a, b, c, in this figure correspond to cp, cf, and ar in figs. 525,
526.
Cycadeoidea dacotensis (McBride).
McBride[1157] first described this Lower Cretaceous species from the
Black Hills of South Dakota as Bennettites dacotensis, the generic name
Cycadeoidea being adopted by Ward[1158] who distinguished some of
McBride’s specimens as Cycadeoidea McBridei. The stem is elliptical in
section, 32 cm. long and 45 cm. in girth: owing to the partial decay of the
petiole-bases the ramental reticulum forms a prominent feature. Numerous
flowers, all of which are approximately at the same stage of development,
Page 445
project like conical buttons above the general level of the stem-surface[1159].
The bisporangiate flowers consist of a conical receptacle bearing
interseminal scales and megasporophylls, the whole being surrounded by
spirally disposed bracts (fig. 529). A whorl of 18 or 19 nearly mature
microsporophylls is attached to the base of the receptacle (figs. 528, 530);
each microsporophyll has a strong rachis extending beyond the apex of the
flower-axis and bent inwards and downwards with the distal end tucked
between the ascending rachis and the receptacle. The slender pinnules, in
two alternate series, are bent downwards and bear synangia in rows. A
transverse section just below the ovulate portion of the cone shows a
continuous ring of tissue encircling the receptacle with vascular bundles
parallel to the surface (fig. 530, A, m); at a higher level the bundles fall into
groups preparatory to the breaking up of the disc into separate
microsporophylls. Immediately above the apex of the central cone the
coherent basal portion of the verticil of sporophylls is replaced by the
separate rachises which in section have the form of isosceles triangles (fig.
530, B). Each microsporophyll is approximately 10 cm. long; the longest
pinnule being 1·5 cm. in length and bearing two lateral series of synangia,
10 in each row. At maturity the microsporophylls probably spread out and
the whole whorl was thrown off leaving an annular rim (fig. 514, d) such as
is often seen at the base of older ovulate strobili. The immaturity of the
ovules in this (fig. 528) and other specimens led to the suggestion that the
strobili of Cycadeoidea were protandrous. The synangia (fig. 531) are
several times broader than long and similar in size to those of the Fern
Marattia. In each synangium are two rows of elongated loculi (fig. 532)
containing oval microspores usually with a smooth exine and rather larger
than those of recent Cycads. The synangium-wall is composed of a
palisade-layer of thick-walled cells and a layer of smaller and thinner cells:
the palisade-layer is narrowest at the apex where dehiscence occurs and
broadest at the base where the hypodermal tissue is more abundant and
forms a short thick pedicel. The two rows of loculi are bounded by flattened
cells and there are 10–20 loculi in each of the two rows: dehiscence of the
individual loculi occurs in the middle of the inner wall.
The bisporangiate flowers consist of a conical receptacle bearing
interseminal scales and megasporophylls, the whole being surrounded by
spirally disposed bracts (fig. 529). A whorl of 18 or 19 nearly mature
microsporophylls is attached to the base of the receptacle (figs. 528, 530);
each microsporophyll has a strong rachis extending beyond the apex of the
flower-axis and bent inwards and downwards with the distal end tucked
between the ascending rachis and the receptacle. The slender pinnules, in
two alternate series, are bent downwards and bear synangia in rows. A
transverse section just below the ovulate portion of the cone shows a
continuous ring of tissue encircling the receptacle with vascular bundles
parallel to the surface (fig. 530, A, m); at a higher level the bundles fall into
groups preparatory to the breaking up of the disc into separate
microsporophylls. Immediately above the apex of the central cone the
coherent basal portion of the verticil of sporophylls is replaced by the
separate rachises which in section have the form of isosceles triangles (fig.
530, B). Each microsporophyll is approximately 10 cm. long; the longest
pinnule being 1·5 cm. in length and bearing two lateral series of synangia,
10 in each row. At maturity the microsporophylls probably spread out and
the whole whorl was thrown off leaving an annular rim (fig. 514, d) such as
is often seen at the base of older ovulate strobili. The immaturity of the
ovules in this (fig. 528) and other specimens led to the suggestion that the
strobili of Cycadeoidea were protandrous. The synangia (fig. 531) are
several times broader than long and similar in size to those of the Fern
Marattia. In each synangium are two rows of elongated loculi (fig. 532)
containing oval microspores usually with a smooth exine and rather larger
than those of recent Cycads. The synangium-wall is composed of a
palisade-layer of thick-walled cells and a layer of smaller and thinner cells:
the palisade-layer is narrowest at the apex where dehiscence occurs and
broadest at the base where the hypodermal tissue is more abundant and
forms a short thick pedicel. The two rows of loculi are bounded by flattened
cells and there are 10–20 loculi in each of the two rows: dehiscence of the
individual loculi occurs in the middle of the inner wall.
Page 446
Fig. 528. Cycadeoidea dacotensis. Longitudinal section through a
bisporangiate strobilus; s, folded microsporophylls with synangia;
o, receptacle bearing short megasporophylls and interseminal
scales; a, eroded surface of bracts; r, ramenta between the bracts
bisporangiate strobilus; s, folded microsporophylls with synangia;
o, receptacle bearing short megasporophylls and interseminal
scales; a, eroded surface of bracts; r, ramenta between the bracts
Page 447
and leaf-bases; l, leaf-base; c, cortex of stem; t, vascular cylinder of
peduncle. (After Wieland; nat. size.)
peduncle. (After Wieland; nat. size.)
Page 448
Fig. 529. Cycadeoidea dacotensis. Transverse sections of a young ovulate
strobilus. A, near the summit of the strobilus 2 cm. below the
surface of the armour of leaf-bases, showing numerous bracts
surrounding the receptacle and embedded in a mass of ramenta,
also sections of some leaf-bases with vascular bundles. B, in this
strobilus. A, near the summit of the strobilus 2 cm. below the
surface of the armour of leaf-bases, showing numerous bracts
surrounding the receptacle and embedded in a mass of ramenta,
also sections of some leaf-bases with vascular bundles. B, in this
Page 449
section, 2·5 cm. below A, the peduncle of the strobilus is seen with
a cylinder of vascular bundles; b, a bract belonging to an adjacent
strobilus. (After Wieland; nat. size.)
Fig. 530. Cycadeoidea dacotensis. Transverse sections through a
bisporangiate strobilus. A, showing the receptacle with its
interseminal scales and ovules, the continuous disc of
microsporophylls, m, with vascular bundles, and the separate (m′)
infolded portions of the microsporophylls with some synangia;
bracts and ramenta. B, this section, cut above the apex of the
receptacle, shows the microsporophylls and synangia. (After
Wieland.)
a cylinder of vascular bundles; b, a bract belonging to an adjacent
strobilus. (After Wieland; nat. size.)
Fig. 530. Cycadeoidea dacotensis. Transverse sections through a
bisporangiate strobilus. A, showing the receptacle with its
interseminal scales and ovules, the continuous disc of
microsporophylls, m, with vascular bundles, and the separate (m′)
infolded portions of the microsporophylls with some synangia;
bracts and ramenta. B, this section, cut above the apex of the
receptacle, shows the microsporophylls and synangia. (After
Wieland.)
Page 450
Fig. 531. Cycadeoidea dacotensis. Synangia exposed by weathering and
showing the radially disposed loculi. (After Wieland; × 6.)
Cycadeoidea Marshiana Ward.
This Lower Cretaceous Black Hills species[1160] affords an admirable
example of a method of branching exhibited by some stems: as shown in
Wieland’s photographs[1161] there may be five or six large and massive
trunks all in the same stage of fructification, differing but little in size and
forming a cluster resembling independent plants growing in close proximity
to one another. There is apparently no central or major axis and the habit is
therefore very different from that of a branching Bucklandia. Cycadeoidea
Marshiana bore large ovulate pyriform strobili projecting slightly beyond
the leaf-bases; they are 5 cm. long with a maximum diameter of 3·5 cm.
and have an elongated receptacle bearing short scales and sporophylls. The
apical bud of one of the trunks shows particularly well in transverse section
the dense ramental packing between the bud-scales[1162]. Similar clusters of
short and thick trunks occur in Cycadeoidea superba and other American
species.
In the small bisporangiate flowers of this species[1163] the
microsporophylls, 11 or 12 in the verticil, are characterised by the presence
of a ventral furrow which, as Wieland suggests, may be comparable on a
much simpler scale with the winged sporophylls of Cycadeoidea colossalis
(fig. 533). The disc splits up at a distance of 1 cm. above the apex of the
receptacle into the microsporophylls, each of which is 5·5 cm. long and
bears two rows of pinnules which in the middle region have a length of 1
cm.; a microsporophyll is elongate, elliptical, and acuminate. In this species
showing the radially disposed loculi. (After Wieland; × 6.)
Cycadeoidea Marshiana Ward.
This Lower Cretaceous Black Hills species[1160] affords an admirable
example of a method of branching exhibited by some stems: as shown in
Wieland’s photographs[1161] there may be five or six large and massive
trunks all in the same stage of fructification, differing but little in size and
forming a cluster resembling independent plants growing in close proximity
to one another. There is apparently no central or major axis and the habit is
therefore very different from that of a branching Bucklandia. Cycadeoidea
Marshiana bore large ovulate pyriform strobili projecting slightly beyond
the leaf-bases; they are 5 cm. long with a maximum diameter of 3·5 cm.
and have an elongated receptacle bearing short scales and sporophylls. The
apical bud of one of the trunks shows particularly well in transverse section
the dense ramental packing between the bud-scales[1162]. Similar clusters of
short and thick trunks occur in Cycadeoidea superba and other American
species.
In the small bisporangiate flowers of this species[1163] the
microsporophylls, 11 or 12 in the verticil, are characterised by the presence
of a ventral furrow which, as Wieland suggests, may be comparable on a
much simpler scale with the winged sporophylls of Cycadeoidea colossalis
(fig. 533). The disc splits up at a distance of 1 cm. above the apex of the
receptacle into the microsporophylls, each of which is 5·5 cm. long and
bears two rows of pinnules which in the middle region have a length of 1
cm.; a microsporophyll is elongate, elliptical, and acuminate. In this species
Page 451
as in some others there is a brush of sterile
scales at the apex of the receptacle.
Cycadeoidea colossalis Ward.
Wieland[1164] has recently described some
interesting features in the microsporophylls of a
bisporangiate flower assigned to this Lower
Cretaceous species from the Black Hills
illustrating a departure from the usual type. The
hairy bracts extend considerably above the apex
of the flower-proper; in fig. 533, A, a transverse
section above the receptacle, they are shown
grouped about a circle of V-shaped structures,
converging towards a central point, which are
the sterile prolongations of the ten rachises of
the free portions of the staminate disc. Each
rachis is divided by a deep ventral furrow into a
pair of wings (fig. 533, B, C), and it is these
pairs of wings that form the V-shaped structures
in fig. 533, A. The wings form a dome-like
group above the flower-apex (fig. 533, D, E).
The synangia are borne in two rows on the Fig. 532. Cycadeoidea
concrescent disc and on the free sporophylls, dacotensis. Synangium
which in this type are much simpler than in in longitudinal section
other species and agree in the absence of showing the thick
pinnules with some forms of Williamsonia (cf. pedicel, the line of
fig. 556). The receptacle is pyriform and bears dehiscence, and two
very short scales and seed-stalks; from its apex loculi with a few
several interseminal scales are prolonged as a microspores. (After
terminal brush, a feature of interest in Wieland; × 40.)
connexion with flowers of Williamsonia.
Wieland compares the wings of the microsporophylls to the two horns on
the distal surface of the corresponding organs of Ceratozamia and draws a
comparison between them and the canopy of some Palaeozoic seeds, but it
is doubtful whether homologies can be established between these elaborate
sporophylls and the integuments of Pteridosperm seeds[1165].
scales at the apex of the receptacle.
Cycadeoidea colossalis Ward.
Wieland[1164] has recently described some
interesting features in the microsporophylls of a
bisporangiate flower assigned to this Lower
Cretaceous species from the Black Hills
illustrating a departure from the usual type. The
hairy bracts extend considerably above the apex
of the flower-proper; in fig. 533, A, a transverse
section above the receptacle, they are shown
grouped about a circle of V-shaped structures,
converging towards a central point, which are
the sterile prolongations of the ten rachises of
the free portions of the staminate disc. Each
rachis is divided by a deep ventral furrow into a
pair of wings (fig. 533, B, C), and it is these
pairs of wings that form the V-shaped structures
in fig. 533, A. The wings form a dome-like
group above the flower-apex (fig. 533, D, E).
The synangia are borne in two rows on the Fig. 532. Cycadeoidea
concrescent disc and on the free sporophylls, dacotensis. Synangium
which in this type are much simpler than in in longitudinal section
other species and agree in the absence of showing the thick
pinnules with some forms of Williamsonia (cf. pedicel, the line of
fig. 556). The receptacle is pyriform and bears dehiscence, and two
very short scales and seed-stalks; from its apex loculi with a few
several interseminal scales are prolonged as a microspores. (After
terminal brush, a feature of interest in Wieland; × 40.)
connexion with flowers of Williamsonia.
Wieland compares the wings of the microsporophylls to the two horns on
the distal surface of the corresponding organs of Ceratozamia and draws a
comparison between them and the canopy of some Palaeozoic seeds, but it
is doubtful whether homologies can be established between these elaborate
sporophylls and the integuments of Pteridosperm seeds[1165].
Page 452
Cycadeoidea Reichenbachiana (Goeppert).
Goeppert referred this species to his genus Raumeria[1166], a generic name
retained by Carruthers though, as Solms-Laubach[1167] points out, the
abundance of lateral fertile shoots among the leaf-bases shows it to be
essentially similar to Cycadeoidea Gibsoniana. The type-specimen in the
Dresden Museum is a splendid example of a fossil cycadean stem; it is
probably of Lower Cretaceous age, but was found in Galicia as an isolated
specimen. It consists of a portion of a cylindrical trunk similar in habit to C.
gigantea, ·5 met. high and about the same in diameter. The pith, according
to Schuster[1168], is 13 cm. in diameter and the xylem 8 cm. broad. There are
many flowering shoots some of which are represented by cup-like
depressions, the base of the cup consisting of the cylindrical axis and the
sides bearing the impress of the encircling bracts (fig. 534). Goeppert
compared these lateral shoots with the buds frequently produced on the
stems of Cycas. It is interesting to find that some of the cups correspond
very closely in size with Williamsonia flowers, another indication of the
very close agreement between the Williamsonia and Bennettites types of
strobili. Some flowers still in place show 16 bipinnate microsporophylls
that were petrified before the synangium-bearing fronds unfolded[1169]. The
ramental scales and other tissues figured by Schuster are of the usual type.
A second specimen found as a boulder in Silesia and named by Goeppert
Raumeria Schulziana may, as he suggests, be a younger example of C.
Reichenbachiana. Another Galician stem, probably also Lower Cretaceous
in age, is described by Raciborski[1170] as Cycadeoidea Niedźwiedzkii.
Goeppert referred this species to his genus Raumeria[1166], a generic name
retained by Carruthers though, as Solms-Laubach[1167] points out, the
abundance of lateral fertile shoots among the leaf-bases shows it to be
essentially similar to Cycadeoidea Gibsoniana. The type-specimen in the
Dresden Museum is a splendid example of a fossil cycadean stem; it is
probably of Lower Cretaceous age, but was found in Galicia as an isolated
specimen. It consists of a portion of a cylindrical trunk similar in habit to C.
gigantea, ·5 met. high and about the same in diameter. The pith, according
to Schuster[1168], is 13 cm. in diameter and the xylem 8 cm. broad. There are
many flowering shoots some of which are represented by cup-like
depressions, the base of the cup consisting of the cylindrical axis and the
sides bearing the impress of the encircling bracts (fig. 534). Goeppert
compared these lateral shoots with the buds frequently produced on the
stems of Cycas. It is interesting to find that some of the cups correspond
very closely in size with Williamsonia flowers, another indication of the
very close agreement between the Williamsonia and Bennettites types of
strobili. Some flowers still in place show 16 bipinnate microsporophylls
that were petrified before the synangium-bearing fronds unfolded[1169]. The
ramental scales and other tissues figured by Schuster are of the usual type.
A second specimen found as a boulder in Silesia and named by Goeppert
Raumeria Schulziana may, as he suggests, be a younger example of C.
Reichenbachiana. Another Galician stem, probably also Lower Cretaceous
in age, is described by Raciborski[1170] as Cycadeoidea Niedźwiedzkii.
Page 453
Fig. 533. Cycadeoidea colossalis. Diagrammatic restorations of the
bisporangiate flower. A, transverse section above the receptacle
showing the bracts (black), a petiole with vascular bundles,
bisporangiate flower. A, transverse section above the receptacle
showing the bracts (black), a petiole with vascular bundles,
Page 454
ramenta, and (1–10) the wings of the microsporophylls. B, C,
longitudinal section of flower showing the receptacle with the
small megasporophylls, the staminate disc with winged
microsporophylls and synangia, and the terminal brush of
interseminal scales (indicated by the arrow in B). The
megasporophylls and synangia are represented larger than the
actual size. D, this shows on one side the dome-like arrangement of
the microsporophylls and, on the right, a microsporophyll in side-
view. E, longitudinal section as far as the plane T surmounted by
the apex of the collection of microsporophylls, c; s,
microsporophyll with synangia; A, recurved apex of
microsporophyll; B, bracts; D, insertion of disc; L, outer bracts
next the petiole bases. (After Wieland; ca. nat. size.)
longitudinal section of flower showing the receptacle with the
small megasporophylls, the staminate disc with winged
microsporophylls and synangia, and the terminal brush of
interseminal scales (indicated by the arrow in B). The
megasporophylls and synangia are represented larger than the
actual size. D, this shows on one side the dome-like arrangement of
the microsporophylls and, on the right, a microsporophyll in side-
view. E, longitudinal section as far as the plane T surmounted by
the apex of the collection of microsporophylls, c; s,
microsporophyll with synangia; A, recurved apex of
microsporophyll; B, bracts; D, insertion of disc; L, outer bracts
next the petiole bases. (After Wieland; ca. nat. size.)
Page 455
Fig. 534. Cycadeoidea Reichenbachiana. Cup-like cavity on the stem
showing the axis and surrounding bracts of a lateral fertile shoot.
(After Schuster, from a block kindly supplied by Prof. Rothpletz.)
Cycadeoidea gigantea Seward.
This species is founded on a large stem from the Upper Purbeck series of
the Isle of Portland[1171] where it was discovered in a shaly clay 17 ft above
the great Dirt bed which yielded the trunks described by Buckland and
other authors (fig. 535). The stem (fig. 554) is 1 met. 18 cm. high and has a
maximum diameter of 1 met. 7 cm. It is the tallest fossil Cycadean stem so
far found in a single piece though Cycadeoidea Jenneyana probably
reached a greater height. The stem is elliptical in section (fig. 537), a form
due in part at least to compression. The only tissues preserved are in the
superficial region of the persistent leaf-bases. As the result of decay before
mineralisation many of the petiole-bases are represented by cavities or
showing the axis and surrounding bracts of a lateral fertile shoot.
(After Schuster, from a block kindly supplied by Prof. Rothpletz.)
Cycadeoidea gigantea Seward.
This species is founded on a large stem from the Upper Purbeck series of
the Isle of Portland[1171] where it was discovered in a shaly clay 17 ft above
the great Dirt bed which yielded the trunks described by Buckland and
other authors (fig. 535). The stem (fig. 554) is 1 met. 18 cm. high and has a
maximum diameter of 1 met. 7 cm. It is the tallest fossil Cycadean stem so
far found in a single piece though Cycadeoidea Jenneyana probably
reached a greater height. The stem is elliptical in section (fig. 537), a form
due in part at least to compression. The only tissues preserved are in the
superficial region of the persistent leaf-bases. As the result of decay before
mineralisation many of the petiole-bases are represented by cavities or
Page 456
meshes in a prominent reticulum of silicified ramental scales. Towards the
apex the leaf-bases are smaller and a conical bud surrounded by linear
scale-leaves occupies the summit: an irregular cap of ramental scales forms
the apex of the terminal bud. In section the bud would no doubt present an
appearance like that shown in Wieland’s photograph of the terminal cone of
C. Marshiana[1172]. There is a striking resemblance both in the ramental cap
and in the form of the protective scales between the fossil stem and such a
Cycad as Encephalartos Altensteinii[1173]. A remarkable feature of C.
gigantea is the absence of any fertile shoots among the leaf-bases. In one
tangential section a small bud was found, but it affords no evidence of the
presence of any reproductive organs. A similar bud is described by
Lignier[1174] in the stem of C. micromyela. The absence of lateral flowers is,
however, hardly a sufficient reason for separating this stem generically from
other species of Cycadeoidea: negative evidence in this case is of doubtful
value. While it is possible that the strobili were terminal as in most recent
Cycads, it is more probable that they were lateral. The surface-features,
though not perfect, are for the most part sufficiently well preserved to
enable one to recognise the bract-encircled axes of strobili were any
present. If as Wieland believes, and he is probably correct, the production of
flowers was the culminating event in the life of these Cycadean plants, the
absence of fertile shoots is merely an expression of immaturity. It is,
however, difficult to understand how lateral branches could find their way
to the surface among the crowded and cork-covered leaf-bases of the stem.
The absence of flowers may be due to some unfavourable external
conditions. The petioles consist of parenchymatous ground-tissue with
many secretory sacs and in some cases twelve partially preserved vascular
bundles: the xylem consists of radial rows of centrifugal tracheids and
medullary rays, but it is not possible to say whether any centripetal xylem
was present. A fairly thick band of phelloderm and periderm, apparently
subepidermal in origin, forms the peripheral tissue, and in places epidermal
cells with attached ramenta are clearly preserved. The ramenta are of the
type characteristic of the majority of fossil Cycadean stems. Stomata were
found showing a pair of guard-cells and apparently two subsidiary cells: the
epidermal cells have straight walls.
apex the leaf-bases are smaller and a conical bud surrounded by linear
scale-leaves occupies the summit: an irregular cap of ramental scales forms
the apex of the terminal bud. In section the bud would no doubt present an
appearance like that shown in Wieland’s photograph of the terminal cone of
C. Marshiana[1172]. There is a striking resemblance both in the ramental cap
and in the form of the protective scales between the fossil stem and such a
Cycad as Encephalartos Altensteinii[1173]. A remarkable feature of C.
gigantea is the absence of any fertile shoots among the leaf-bases. In one
tangential section a small bud was found, but it affords no evidence of the
presence of any reproductive organs. A similar bud is described by
Lignier[1174] in the stem of C. micromyela. The absence of lateral flowers is,
however, hardly a sufficient reason for separating this stem generically from
other species of Cycadeoidea: negative evidence in this case is of doubtful
value. While it is possible that the strobili were terminal as in most recent
Cycads, it is more probable that they were lateral. The surface-features,
though not perfect, are for the most part sufficiently well preserved to
enable one to recognise the bract-encircled axes of strobili were any
present. If as Wieland believes, and he is probably correct, the production of
flowers was the culminating event in the life of these Cycadean plants, the
absence of fertile shoots is merely an expression of immaturity. It is,
however, difficult to understand how lateral branches could find their way
to the surface among the crowded and cork-covered leaf-bases of the stem.
The absence of flowers may be due to some unfavourable external
conditions. The petioles consist of parenchymatous ground-tissue with
many secretory sacs and in some cases twelve partially preserved vascular
bundles: the xylem consists of radial rows of centrifugal tracheids and
medullary rays, but it is not possible to say whether any centripetal xylem
was present. A fairly thick band of phelloderm and periderm, apparently
subepidermal in origin, forms the peripheral tissue, and in places epidermal
cells with attached ramenta are clearly preserved. The ramenta are of the
type characteristic of the majority of fossil Cycadean stems. Stomata were
found showing a pair of guard-cells and apparently two subsidiary cells: the
epidermal cells have straight walls.
Page 457
Fig. 535. Section of the
quarry in the Isle of
Portland in which
Cycadeoidea gigantea was
found.
quarry in the Isle of
Portland in which
Cycadeoidea gigantea was
found.
Page 458
Fig. 536. Cycadeoidea gigantea. (The
original is in the British Museum; ⅛ nat.
size.)
Fig. 537. Cycadeoidea gigantea. Transverse section of the stem.
Fig. 538. Cycadeoidea micromyela. A, tracheids from the stele. B, course
of the vascular bundles at the base of a leaf. C, section of a leaf-
trace entering the stele; m, l, median and lateral lobes of the trace.
(After Lignier.)
Cycadeoidea micromyela Morière.
This Liassic species from Normandy has been fully investigated by
Lignier[1175]; originally referred to the Conifers, it was afterwards described
original is in the British Museum; ⅛ nat.
size.)
Fig. 537. Cycadeoidea gigantea. Transverse section of the stem.
Fig. 538. Cycadeoidea micromyela. A, tracheids from the stele. B, course
of the vascular bundles at the base of a leaf. C, section of a leaf-
trace entering the stele; m, l, median and lateral lobes of the trace.
(After Lignier.)
Cycadeoidea micromyela Morière.
This Liassic species from Normandy has been fully investigated by
Lignier[1175]; originally referred to the Conifers, it was afterwards described
Page 459
by Morière[1176] as Cycadeoidea micromyela. As regards external features
the stem is of the usual Cycadeoidea type: Saporta[1177] assigned it to the
genus Platylepis. The secondary xylem consists of tracheids with bordered
pits on the radial walls arranged as single contiguous rows, resembling
scalariform pitting, or as 1–2 rows of separate circular pits (fig. 538, A), a
type different from that of the great majority of Mesozoic species. The
uniseriate medullary rays are 7–20 cells deep, a character recalling the
compact wood of Indian Williamsonia stems. Ramental scales are for the
most part replaced by long unicellular hairs like those of Williamsonia
scotica and some Indian stems. Lignier states that true ramenta occur on the
young leaves and in older fronds become transformed by separation of the
cells into long tubes. Each leaf-trace arises as a single bundle dividing into
three as it leaves the stele and eventually splits up into several collateral
bundles (fig. 538, B, C). The stele is elliptical. No fertile shoots are
preserved: a single axillary bud is described which agrees very closely with
that in Cycadeoidea gigantea.
the stem is of the usual Cycadeoidea type: Saporta[1177] assigned it to the
genus Platylepis. The secondary xylem consists of tracheids with bordered
pits on the radial walls arranged as single contiguous rows, resembling
scalariform pitting, or as 1–2 rows of separate circular pits (fig. 538, A), a
type different from that of the great majority of Mesozoic species. The
uniseriate medullary rays are 7–20 cells deep, a character recalling the
compact wood of Indian Williamsonia stems. Ramental scales are for the
most part replaced by long unicellular hairs like those of Williamsonia
scotica and some Indian stems. Lignier states that true ramenta occur on the
young leaves and in older fronds become transformed by separation of the
cells into long tubes. Each leaf-trace arises as a single bundle dividing into
three as it leaves the stele and eventually splits up into several collateral
bundles (fig. 538, B, C). The stele is elliptical. No fertile shoots are
preserved: a single axillary bud is described which agrees very closely with
that in Cycadeoidea gigantea.
Page 460
Fig. 539. Cycadeoidea Jenneyana (?). Longitudinal section of an ovulate
strobilus, showing the pyriform receptacle with vascular supply,
the long interseminal scales and megasporophylls, and a few of the
surrounding bracts. (After Wieland; × 1½ nat. size.)
Cycadeoidea Jenneyana Ward.
The stems of this species, from the Black Hills of Dakota[1178], resemble
those of Cycadeoidea gigantea and C. Reichenbachiana in their thick
columnar form but differ from the former in the presence of bisporangiate
flowers associated with the leaf-bases. This species probably reached a
length of 3–4 met. A striking feature[1179] is the unusual thickness of the
strobilus, showing the pyriform receptacle with vascular supply,
the long interseminal scales and megasporophylls, and a few of the
surrounding bracts. (After Wieland; × 1½ nat. size.)
Cycadeoidea Jenneyana Ward.
The stems of this species, from the Black Hills of Dakota[1178], resemble
those of Cycadeoidea gigantea and C. Reichenbachiana in their thick
columnar form but differ from the former in the presence of bisporangiate
flowers associated with the leaf-bases. This species probably reached a
length of 3–4 met. A striking feature[1179] is the unusual thickness of the
Page 461
xylem-cylinder, which shows clear indications of concentric rings, probably
the expression of seasonal changes during the production of secondary
conducting tissue by a single cambium. Similar concentric rings have been
described in the stems of the recent Cycad Dioon spinulosum[1180]. Fig. 539
represents an ovulate strobilus referred to this species by Wieland.
Cycadeoidea pumila Fliche and Zeiller.
This French Portlandian species[1181] affords a good example of a very
small bulbiform trunk, 3·5–4 by 2·5–3 cm., superficially resembling a Pine-
cone: the leaf-bases are, however, less uniform in size and shape than
Abietineous cone-scales; there are also indications of interpetiolar ramenta
and a small lateral, presumably fertile, branch. A stem of similar form is
described by Saporta[1182] from Corallian beds in France as Bulbopodium
micromerum, and Cycadeoidea nana Ward[1183] from Dakota is another
example of a small Zamia-like Mesozoic stem. A small tuberous stem, 8 ×
7·5 cm., was described by Lindley and Button from Lyme Regis as
Cycadeoidea pygmaea[1184]; no flowers are shown in the drawing, but
occasional irregularities in the arrangement of the leaf-bases may be due to
the presence of lateral fertile shoots.
Cycadella. Ward.
This generic name was instituted by Lester Ward[1185] for some petrified
stems from Jurassic beds in Wyoming of relatively small size, bulbous or
more or less spherical, and characterised by the presence of a thick layer
(5–15 mm.) of dense ramental tissue. The unusually vigorous development
of the ramental scales is an interesting feature, though it is perhaps
questionable whether it is worthy of generic recognition. The flowers of
Cycadella, though less than those of most Cycadeoidea stems, are of the
same type. In a later account of the genus Ward[1186] describes a few
additional species and in Cycadella ramentosa he notes the preservation of
young fronds. The fronds are small and bear a few pinnae: the xylem is said
by Wieland[1187] to be mesarch, but in the absence of more details the foliar
bundles cannot be fully described. In some Cycadellas young flowers, less
than 1 cm. in diameter, are preserved, those of Cycadella wyomingensis (7
mm. in diameter) being the smallest bisporangiate strobili so far recorded.
The French species, Cycadeoidea micromyela Mor., resembles Cycadella in
the expression of seasonal changes during the production of secondary
conducting tissue by a single cambium. Similar concentric rings have been
described in the stems of the recent Cycad Dioon spinulosum[1180]. Fig. 539
represents an ovulate strobilus referred to this species by Wieland.
Cycadeoidea pumila Fliche and Zeiller.
This French Portlandian species[1181] affords a good example of a very
small bulbiform trunk, 3·5–4 by 2·5–3 cm., superficially resembling a Pine-
cone: the leaf-bases are, however, less uniform in size and shape than
Abietineous cone-scales; there are also indications of interpetiolar ramenta
and a small lateral, presumably fertile, branch. A stem of similar form is
described by Saporta[1182] from Corallian beds in France as Bulbopodium
micromerum, and Cycadeoidea nana Ward[1183] from Dakota is another
example of a small Zamia-like Mesozoic stem. A small tuberous stem, 8 ×
7·5 cm., was described by Lindley and Button from Lyme Regis as
Cycadeoidea pygmaea[1184]; no flowers are shown in the drawing, but
occasional irregularities in the arrangement of the leaf-bases may be due to
the presence of lateral fertile shoots.
Cycadella. Ward.
This generic name was instituted by Lester Ward[1185] for some petrified
stems from Jurassic beds in Wyoming of relatively small size, bulbous or
more or less spherical, and characterised by the presence of a thick layer
(5–15 mm.) of dense ramental tissue. The unusually vigorous development
of the ramental scales is an interesting feature, though it is perhaps
questionable whether it is worthy of generic recognition. The flowers of
Cycadella, though less than those of most Cycadeoidea stems, are of the
same type. In a later account of the genus Ward[1186] describes a few
additional species and in Cycadella ramentosa he notes the preservation of
young fronds. The fronds are small and bear a few pinnae: the xylem is said
by Wieland[1187] to be mesarch, but in the absence of more details the foliar
bundles cannot be fully described. In some Cycadellas young flowers, less
than 1 cm. in diameter, are preserved, those of Cycadella wyomingensis (7
mm. in diameter) being the smallest bisporangiate strobili so far recorded.
The French species, Cycadeoidea micromyela Mor., resembles Cycadella in
Page 462
the profuse development of ramental tissue which may cover the surface of
the stem.
Amphibennettites. Fliche.
This generic name was instituted[1188] for two species founded on very
imperfectly preserved ‘fruits’ of Lower Cretaceous (Albian) age from the
Argonne which, though in close agreement with Bennettites as represented
by B. Gibsonianus and B. Morierei, are referred to a separate genus on the
ground that the preservation is not such as to establish their generic identity
with those species and because of certain distinctive features.
Amphibennettites Bleicheri Fliche. The ovulate strobili are sub-elliptical,
3·5 × 3 cm., with several elliptical pits close to the surface originally
occupied by seeds borne on short stalks and larger than the seeds of other
species of Cycadeoidea (Bennettites). Interseminal scales occur between the
seeds. The second species, Amphibennettites Renaulti, is rather larger and
more conical: the seeds reach a length of 11 mm. greater than that of any of
the American seeds described by Wieland. In neither species is there any
indication of an involucre of bracts. The preservation of the specimens
leaves much to be desired, but it would seem that the Argonne fossils agree
in their main characters with Bennettitean strobili and it is doubtful whether
a distinctive generic name is necessary. The occurrence of seeds over the
whole surface, a feature that suggested the name Amphibennettites, may be
only apparent and the result of cutting the cone transversely. It is worthy of
note that one of Fliche’s sections[1189] bears a close resemblance to an
Araucarian cone, and in the absence of structure the two types of cone
might easily be confused.
the stem.
Amphibennettites. Fliche.
This generic name was instituted[1188] for two species founded on very
imperfectly preserved ‘fruits’ of Lower Cretaceous (Albian) age from the
Argonne which, though in close agreement with Bennettites as represented
by B. Gibsonianus and B. Morierei, are referred to a separate genus on the
ground that the preservation is not such as to establish their generic identity
with those species and because of certain distinctive features.
Amphibennettites Bleicheri Fliche. The ovulate strobili are sub-elliptical,
3·5 × 3 cm., with several elliptical pits close to the surface originally
occupied by seeds borne on short stalks and larger than the seeds of other
species of Cycadeoidea (Bennettites). Interseminal scales occur between the
seeds. The second species, Amphibennettites Renaulti, is rather larger and
more conical: the seeds reach a length of 11 mm. greater than that of any of
the American seeds described by Wieland. In neither species is there any
indication of an involucre of bracts. The preservation of the specimens
leaves much to be desired, but it would seem that the Argonne fossils agree
in their main characters with Bennettitean strobili and it is doubtful whether
a distinctive generic name is necessary. The occurrence of seeds over the
whole surface, a feature that suggested the name Amphibennettites, may be
only apparent and the result of cutting the cone transversely. It is worthy of
note that one of Fliche’s sections[1189] bears a close resemblance to an
Araucarian cone, and in the absence of structure the two types of cone
might easily be confused.
Page 463
Fig. 540. Vectia luccombensis. Transverse section showing the
alternation of fibres, s1, s2, and radial pairs of pitted elements, v1
and v2; m, medullary-ray cells; a, parenchyma cell between four
thin-walled elements; sp, pits between adjacent fibres; l, much
reduced lumen of fibre. (After Stopes.)
Vectia. Stopes. Genus incertae sedis.
Vectia luccombensis Stopes.
The generic name Vectia has been given by Dr Stopes[1190] to some
petrified secondary phloem discovered by her at Luccomb Chine in the Isle
of Wight: the fossil is from Aptian beds. The mass of phloem is 26 mm. in
breadth and consists of regularly alternating bands of thin-walled sieve-
tubes and very thick fibres associated with a little parenchyma (fig. 540). To
the naked eye the specimen presents an appearance suggestive of rings of
growth but this is due to the presence of bands of 2–3 narrow cells which
are probably cork. The whole is penetrated by uniseriate medullary rays. A
striking feature is the regular alternation of single rows of fibres with two
bands of sieve-tubes; in places the two bands of sieve-tubes are separated
by 2–4 rows of very flat, presumably, cork-cells, and similar bands may be
alternation of fibres, s1, s2, and radial pairs of pitted elements, v1
and v2; m, medullary-ray cells; a, parenchyma cell between four
thin-walled elements; sp, pits between adjacent fibres; l, much
reduced lumen of fibre. (After Stopes.)
Vectia. Stopes. Genus incertae sedis.
Vectia luccombensis Stopes.
The generic name Vectia has been given by Dr Stopes[1190] to some
petrified secondary phloem discovered by her at Luccomb Chine in the Isle
of Wight: the fossil is from Aptian beds. The mass of phloem is 26 mm. in
breadth and consists of regularly alternating bands of thin-walled sieve-
tubes and very thick fibres associated with a little parenchyma (fig. 540). To
the naked eye the specimen presents an appearance suggestive of rings of
growth but this is due to the presence of bands of 2–3 narrow cells which
are probably cork. The whole is penetrated by uniseriate medullary rays. A
striking feature is the regular alternation of single rows of fibres with two
bands of sieve-tubes; in places the two bands of sieve-tubes are separated
by 2–4 rows of very flat, presumably, cork-cells, and similar bands may be
Page 464
adjacent to or pass obliquely across the fibres. The elongated elements
described as sieve-tubes, though thin in comparison with the fibres, have
thickened walls and on their radial faces are single rows of circular pits,
often in pairs; these are almost certainly sieve-areas which have lost the
finer pitting of the sieve-plates. The fibres are more or less square in
transverse section and have excessively thick walls, the lumen being
reduced to a small hole. Parenchymatous cells (fig. 540, a) occupy the
angles between the sieve-tubes and occasionally stretch tangentially
between a pair of tubes: these are compared by Dr Stopes to companion-
cells, but their manner of occurrence hardly justifies the interesting
suggestion that they may be precursors of the Angiosperm companion-cells.
The medullary rays may be as wide as the elements which they traverse;
they are characterised by their wavy walls, as seen in radial longitudinal
sections; no pitting was noticed. A remarkable feature of the specimen is its
considerable breadth: it is pointed out that in a giant stem of Sequoia with a
girth of over 40 ft the secondary phloem does not exceed 3–4 mm. in
breadth. The great thickness of the phloem in the fossil suggests comparison
with the corresponding tissue in recent and fossil Cycadean stems, and the
alternation of hard and soft phloem is a feature exhibited also by
Cycadeoidea Gibsoniana (fig. 518, B). Dr Stopes concludes that the phloem
is in the main similar to that in some Cupressineae, Taxineae, and
Taxodineae. It is noteworthy that similar phloem with sieve-tubes and fibres
associated with cork is described by Graf Solms-Laubach[1191] from Upper
Jurassic beds in Franz Josef Land. The systematic position of Vectia cannot
be definitely determined, but I believe that it is more closely allied to
Cycadean than to Coniferous phloem.
Note. It is unfortunate that Mr Wieland’s second volume dealing with
American Cycads [Wieland (16)] did not come into my hands until nearly
the whole of this volume was in type. Students will find in it many
additions to our knowledge of Cycadeoidea and Williamsonia, much
theoretical discussion that is suggestive and interesting, useful summaries
of our knowledge of fossil Cycads, and many beautiful photographic plates
illustrating the morphology of American species of Cycadeoidea.
described as sieve-tubes, though thin in comparison with the fibres, have
thickened walls and on their radial faces are single rows of circular pits,
often in pairs; these are almost certainly sieve-areas which have lost the
finer pitting of the sieve-plates. The fibres are more or less square in
transverse section and have excessively thick walls, the lumen being
reduced to a small hole. Parenchymatous cells (fig. 540, a) occupy the
angles between the sieve-tubes and occasionally stretch tangentially
between a pair of tubes: these are compared by Dr Stopes to companion-
cells, but their manner of occurrence hardly justifies the interesting
suggestion that they may be precursors of the Angiosperm companion-cells.
The medullary rays may be as wide as the elements which they traverse;
they are characterised by their wavy walls, as seen in radial longitudinal
sections; no pitting was noticed. A remarkable feature of the specimen is its
considerable breadth: it is pointed out that in a giant stem of Sequoia with a
girth of over 40 ft the secondary phloem does not exceed 3–4 mm. in
breadth. The great thickness of the phloem in the fossil suggests comparison
with the corresponding tissue in recent and fossil Cycadean stems, and the
alternation of hard and soft phloem is a feature exhibited also by
Cycadeoidea Gibsoniana (fig. 518, B). Dr Stopes concludes that the phloem
is in the main similar to that in some Cupressineae, Taxineae, and
Taxodineae. It is noteworthy that similar phloem with sieve-tubes and fibres
associated with cork is described by Graf Solms-Laubach[1191] from Upper
Jurassic beds in Franz Josef Land. The systematic position of Vectia cannot
be definitely determined, but I believe that it is more closely allied to
Cycadean than to Coniferous phloem.
Note. It is unfortunate that Mr Wieland’s second volume dealing with
American Cycads [Wieland (16)] did not come into my hands until nearly
the whole of this volume was in type. Students will find in it many
additions to our knowledge of Cycadeoidea and Williamsonia, much
theoretical discussion that is suggestive and interesting, useful summaries
of our knowledge of fossil Cycads, and many beautiful photographic plates
illustrating the morphology of American species of Cycadeoidea.
Page 465
Page 466
CHAPTER XXXVII.
BENNETTITALES (continued).
WILLIAMSONIA. Carruthers.
This genus was first figured by Young and Bird[1192] from specimens
obtained from Lower Estuarine beds near Whitby: these authors compared
the fossils to the head of an Artichoke (Cynara integrifolia), ‘the covering
or calyx consisting of numerous lanceolate and striated leaves’ (fig. 544). In
1840 Williamson[1193] noticed the association with fronds of Zamia gigas
Lind. and Hutt. of ‘a remarkable fossil, apparently connected with the
fructification of a Cycas,’ and some years later Yates[1194] expressed the
opinion that the fructifications figured by Young and Bird probably
belonged to the plants which bore the fronds known as Zamites gigas.
Leckenby[1195] figured some leaves of Palaeozamia pecten (= Ptilophyllum
pecten) in close association with a small flower of Williamsonia which was
subsequently recognised as a whorl of microsporophylls. In 1870 two
papers of exceptional interest were published, one by Williamson[1196] who
was the first to attempt an exhaustive account of the genus, and the other by
Carruthers[1197] who proposed the name Williamsonia, thus associating ‘with
a group of the most characteristic Yorkshire fossils two men (father and
son) who have largely contributed to the exposition of Yorkshire geology.’
Carruthers instituted a new tribe Williamsonieae for the genus
Williamsonia, the type-species being Williamsonia gigas: the specific name
had been previously given by Lindley and Hutton to the fronds (Zamia
gigas) of the plant which was believed to have borne the flowers for which
the new designation was proposed. Two other species, Williamsonia hastula
and W. pecten, were assigned to the new genus. The conclusion arrived at
by Williamson as to a connexion between Zamites gigas and Williamsonia
flowers was, however, not accepted by Saporta[1198], who figured and
described several exceptionally good specimens from the Yorkshire coast
which formed part of the Yates collection in the Paris Natural History
Museum. In 1897 a short account was published[1199] of the Yates specimens,
an examination of which convinced me of the correctness of Williamson’s
BENNETTITALES (continued).
WILLIAMSONIA. Carruthers.
This genus was first figured by Young and Bird[1192] from specimens
obtained from Lower Estuarine beds near Whitby: these authors compared
the fossils to the head of an Artichoke (Cynara integrifolia), ‘the covering
or calyx consisting of numerous lanceolate and striated leaves’ (fig. 544). In
1840 Williamson[1193] noticed the association with fronds of Zamia gigas
Lind. and Hutt. of ‘a remarkable fossil, apparently connected with the
fructification of a Cycas,’ and some years later Yates[1194] expressed the
opinion that the fructifications figured by Young and Bird probably
belonged to the plants which bore the fronds known as Zamites gigas.
Leckenby[1195] figured some leaves of Palaeozamia pecten (= Ptilophyllum
pecten) in close association with a small flower of Williamsonia which was
subsequently recognised as a whorl of microsporophylls. In 1870 two
papers of exceptional interest were published, one by Williamson[1196] who
was the first to attempt an exhaustive account of the genus, and the other by
Carruthers[1197] who proposed the name Williamsonia, thus associating ‘with
a group of the most characteristic Yorkshire fossils two men (father and
son) who have largely contributed to the exposition of Yorkshire geology.’
Carruthers instituted a new tribe Williamsonieae for the genus
Williamsonia, the type-species being Williamsonia gigas: the specific name
had been previously given by Lindley and Hutton to the fronds (Zamia
gigas) of the plant which was believed to have borne the flowers for which
the new designation was proposed. Two other species, Williamsonia hastula
and W. pecten, were assigned to the new genus. The conclusion arrived at
by Williamson as to a connexion between Zamites gigas and Williamsonia
flowers was, however, not accepted by Saporta[1198], who figured and
described several exceptionally good specimens from the Yorkshire coast
which formed part of the Yates collection in the Paris Natural History
Museum. In 1897 a short account was published[1199] of the Yates specimens,
an examination of which convinced me of the correctness of Williamson’s
Page 467
views as to an organic connexion between stems, peduncles, flowers, and
fronds. During a visit to Paris several photographs were taken, but these
were not published: similar photographs have since been reproduced by
Wieland[1200] and reduced copies from two negatives in my possession are
shown in figs. 541, 542. The restoration by Williamson in his well-known
memoir is probably correct so far as the general habit of the plant is
concerned, though the flowers which he speaks of as male are now known
to be ovulate. The position of the male organs, whether borne separately or
on the same axis as the megasporophylls, has not been definitely settled.
In 1891 the Marquis of Saporta thus introduced his discussion on
Williamsonia,—‘avec les Williamsonia nous abordons un des problèmes les
plus difficiles, un des sujets des plus controversés, mais aussi les plus
curieux, peut-être même le plus remarquable de tous ceux que nous offre
l’ensemble des plantes jurassiques.’ Wieland’s investigations have placed us
in possession of many important facts with regard to the closely allied
flowers of Cycadeoidea and have enabled us considerably to extend our
knowledge beyond the stage represented by the work of Carruthers,
Williamson, and other authors; and more recently Nathorst’s important
discoveries have demonstrated the close agreement between Williamsonia
and Bennettites (Cycadeoidea). Several problems still remain unsolved.
Having regard to the deficiency of the data concerning the morphology of
the Williamsonia type of flower and the wider question as to a phylogenetic
relationship that some botanists believe to exist between the Bennettitales
and the Angiosperms, Saporta’s words are still pertinent. Wieland’s
discoveries in Mexico[1201] have furnished additional evidence of the wide
geographical distribution of the Williamsonia type of flower in the Jurassic
period, and it may be confidently asserted that the Bennettitales, including
both Williamsonia and Cycadeoidea, occupied a dominant position in the
floras of the world during the stage of plant-development immediately
preceding the evolution and rapid spread of the Angiosperms, the present
dominant class.
There has been considerable uncertainty among authors with regard to
the application of the name Williamsonia. In former accounts of the genus
the name was employed by me both for leaves and flowers on the ground
that Williamson was correct in his opinion as to the connexion between
Williamsonia gigas and Zamites gigas. The type of frond to which the latter
fronds. During a visit to Paris several photographs were taken, but these
were not published: similar photographs have since been reproduced by
Wieland[1200] and reduced copies from two negatives in my possession are
shown in figs. 541, 542. The restoration by Williamson in his well-known
memoir is probably correct so far as the general habit of the plant is
concerned, though the flowers which he speaks of as male are now known
to be ovulate. The position of the male organs, whether borne separately or
on the same axis as the megasporophylls, has not been definitely settled.
In 1891 the Marquis of Saporta thus introduced his discussion on
Williamsonia,—‘avec les Williamsonia nous abordons un des problèmes les
plus difficiles, un des sujets des plus controversés, mais aussi les plus
curieux, peut-être même le plus remarquable de tous ceux que nous offre
l’ensemble des plantes jurassiques.’ Wieland’s investigations have placed us
in possession of many important facts with regard to the closely allied
flowers of Cycadeoidea and have enabled us considerably to extend our
knowledge beyond the stage represented by the work of Carruthers,
Williamson, and other authors; and more recently Nathorst’s important
discoveries have demonstrated the close agreement between Williamsonia
and Bennettites (Cycadeoidea). Several problems still remain unsolved.
Having regard to the deficiency of the data concerning the morphology of
the Williamsonia type of flower and the wider question as to a phylogenetic
relationship that some botanists believe to exist between the Bennettitales
and the Angiosperms, Saporta’s words are still pertinent. Wieland’s
discoveries in Mexico[1201] have furnished additional evidence of the wide
geographical distribution of the Williamsonia type of flower in the Jurassic
period, and it may be confidently asserted that the Bennettitales, including
both Williamsonia and Cycadeoidea, occupied a dominant position in the
floras of the world during the stage of plant-development immediately
preceding the evolution and rapid spread of the Angiosperms, the present
dominant class.
There has been considerable uncertainty among authors with regard to
the application of the name Williamsonia. In former accounts of the genus
the name was employed by me both for leaves and flowers on the ground
that Williamson was correct in his opinion as to the connexion between
Williamsonia gigas and Zamites gigas. The type of frond to which the latter
Page 468
term is applied is by no means uncommon in Jurassic strata though it is not
always associated with flowers, and the use of the generic term
Williamsonia is therefore not invariably justifiable. Nathorst[1202] has
recently reiterated his opinion that it is inadvisable to employ the name
Williamsonia except for the flowers or the complete plant and strongly
urges palaeobotanists to retain the provisional genus Zamites when the
fronds only are in question. While agreeing with the contention that the
greatest care should be exercised to avoid the use of generic names
implying a correlation of vegetative and reproductive organs that rests on
any evidence short of demonstration, it may be suggested that the better
plan is to add the name Williamsonia in parentheses after Zamites or
Ptilophyllum in cases where there is no reason to doubt that the fronds
belong to a Williamsonia plant.
Williamsonia gigas (Williamson).
The species selected for a rather detailed description is still imperfectly
known, but it is particularly interesting as the type on which the first
scientific account of the genus was based. The name Williamsonia gigas is
now generally employed for the flowers which bore megasporophylls as the
essential organs: they may have been bisporangiate,—a view that seems to
me the more probable,—but this has not been demonstrated. There are very
few cases in which fronds of Zamites gigas occur in organic connexion with
stems, and we cannot with safety employ other than a provisional generic
term for fossil stems which it is believed bore flowers of the Williamsonia
type. For the imperfectly preserved piece of stem shown in fig. 541 the
name Williamsonia (Bucklandia) gigas is employed, as there is no
reasonable doubt that in addition to the fronds of Zamites gigas it bore
peduncles (fig. 541, a), with Williamsonia flowers. This and other stems
found in close association with Williamsonia flowers in England, India, and
Mexico are of the type known as Bucklandia[1203]; but it would in most
instances be unwise to add Williamsonia even as a subordinate title. Casts
of stems in close association with fronds and flowers are not uncommon in
collections of plants from the Yorkshire coast; the surface-features are of
the type shown in fig. 576, rhomboidal or lozenge-shaped bases of petioles
as described under the genus Bucklandia[1204]. The stem reproduced in fig.
541, about 5 cm. broad, is imperfectly preserved and the leaf-bases are not
always associated with flowers, and the use of the generic term
Williamsonia is therefore not invariably justifiable. Nathorst[1202] has
recently reiterated his opinion that it is inadvisable to employ the name
Williamsonia except for the flowers or the complete plant and strongly
urges palaeobotanists to retain the provisional genus Zamites when the
fronds only are in question. While agreeing with the contention that the
greatest care should be exercised to avoid the use of generic names
implying a correlation of vegetative and reproductive organs that rests on
any evidence short of demonstration, it may be suggested that the better
plan is to add the name Williamsonia in parentheses after Zamites or
Ptilophyllum in cases where there is no reason to doubt that the fronds
belong to a Williamsonia plant.
Williamsonia gigas (Williamson).
The species selected for a rather detailed description is still imperfectly
known, but it is particularly interesting as the type on which the first
scientific account of the genus was based. The name Williamsonia gigas is
now generally employed for the flowers which bore megasporophylls as the
essential organs: they may have been bisporangiate,—a view that seems to
me the more probable,—but this has not been demonstrated. There are very
few cases in which fronds of Zamites gigas occur in organic connexion with
stems, and we cannot with safety employ other than a provisional generic
term for fossil stems which it is believed bore flowers of the Williamsonia
type. For the imperfectly preserved piece of stem shown in fig. 541 the
name Williamsonia (Bucklandia) gigas is employed, as there is no
reasonable doubt that in addition to the fronds of Zamites gigas it bore
peduncles (fig. 541, a), with Williamsonia flowers. This and other stems
found in close association with Williamsonia flowers in England, India, and
Mexico are of the type known as Bucklandia[1203]; but it would in most
instances be unwise to add Williamsonia even as a subordinate title. Casts
of stems in close association with fronds and flowers are not uncommon in
collections of plants from the Yorkshire coast; the surface-features are of
the type shown in fig. 576, rhomboidal or lozenge-shaped bases of petioles
as described under the genus Bucklandia[1204]. The stem reproduced in fig.
541, about 5 cm. broad, is imperfectly preserved and the leaf-bases are not
Page 469
clearly seen. Saporta’s figure[1205] conveys but a poor idea of the actual
specimen. To one side of the stem, 5 cm. from the lower, broken, end, are
attached the petioles of two clearly preserved fronds of Zamites gigas, and
above these is part of a third frond apparently in its original position. The
main axis is prolonged obliquely upwards to the left as a branch, a, 3 cm.
broad and 14 cm. long, covered with hairy bracts and bearing distally
several narrow, linear-lanceolate, scale-leaves. This branch is undoubtedly a
fertile shoot or peduncle. A specimen figured (from a drawing) by
Saporta[1206] as a peduncle of a Williamsonia flower and reproduced in fig.
542 is, in surface-features, identical with the branch a shown in fig. 541, but
at the apex it bears a bud covered with linear bracts identical with those of
Williamsonia gigas. This bud is almost certainly a young flower. Similar
peduncles are described by Williamson, and he speaks of one which is
bifurcated: this specimen is probably that reproduced in fig. 543 and now in
the Leeds Museum: at the base the axis is 3·5 cm. in diameter; the two
divergent arms bear numerous bracts identical with those of Williamsonia
gigas and in addition are a few shorter ovate scales recalling those figured
by Nathorst as probably belonging to Williamsonia pecten. The Leeds
specimen is from the Lower sandstone and shale near Scarborough. Similar
branched peduncles are represented in the Whitby Museum and in the
National Collection. Wieland[1207] has also figured a peduncle bearing a
‘typical fruit bud’ of Williamsonia gigas similar to that reproduced in fig.
542. These specimens fully justify Williamson’s restoration published in his
paper of 1870.
specimen. To one side of the stem, 5 cm. from the lower, broken, end, are
attached the petioles of two clearly preserved fronds of Zamites gigas, and
above these is part of a third frond apparently in its original position. The
main axis is prolonged obliquely upwards to the left as a branch, a, 3 cm.
broad and 14 cm. long, covered with hairy bracts and bearing distally
several narrow, linear-lanceolate, scale-leaves. This branch is undoubtedly a
fertile shoot or peduncle. A specimen figured (from a drawing) by
Saporta[1206] as a peduncle of a Williamsonia flower and reproduced in fig.
542 is, in surface-features, identical with the branch a shown in fig. 541, but
at the apex it bears a bud covered with linear bracts identical with those of
Williamsonia gigas. This bud is almost certainly a young flower. Similar
peduncles are described by Williamson, and he speaks of one which is
bifurcated: this specimen is probably that reproduced in fig. 543 and now in
the Leeds Museum: at the base the axis is 3·5 cm. in diameter; the two
divergent arms bear numerous bracts identical with those of Williamsonia
gigas and in addition are a few shorter ovate scales recalling those figured
by Nathorst as probably belonging to Williamsonia pecten. The Leeds
specimen is from the Lower sandstone and shale near Scarborough. Similar
branched peduncles are represented in the Whitby Museum and in the
National Collection. Wieland[1207] has also figured a peduncle bearing a
‘typical fruit bud’ of Williamsonia gigas similar to that reproduced in fig.
542. These specimens fully justify Williamson’s restoration published in his
paper of 1870.
Page 470
Fig. 541. Williamsonia gigas. Fronds (Zamites gigas) and flowering
shoot, a, attached to a stem (Bucklandia). (Yates Collection, Paris; nat.
size.)
shoot, a, attached to a stem (Bucklandia). (Yates Collection, Paris; nat.
size.)
Page 471
Fig. 542. Williamsonia gigas. Flowering shoot and flower-bud. (Yates
Collection, Paris.)
In a former account of this species[1208] the opinion was expressed that the
flowers described by Williamson as male were ovulate and constructed on
the plan of those of Bennettites Gibsonianus Carr. This conclusion has since
been confirmed by Nathorst[1209] who succeeded in obtaining excellent
preparations of the cuticular membranes of interseminal scales and
micropylar tubes (fig. 545), demonstrating their very close agreement with
those of the flowers of Cycadeoidea.
Collection, Paris.)
In a former account of this species[1208] the opinion was expressed that the
flowers described by Williamson as male were ovulate and constructed on
the plan of those of Bennettites Gibsonianus Carr. This conclusion has since
been confirmed by Nathorst[1209] who succeeded in obtaining excellent
preparations of the cuticular membranes of interseminal scales and
micropylar tubes (fig. 545), demonstrating their very close agreement with
those of the flowers of Cycadeoidea.
Page 472
Fig. 543. Williamsonia gigas. Two peduncles, B and C, with imperfectly
preserved bracts. Diameter of axis, A, 3·5 cm. (From a specimen in
the Leeds Museum; nat. size.)
One of Williamson’s ‘carpellary discs’ has been shown by Nathorst to be
a verticil of microsporophylls bearing synangia, but both this author and
Lignier[1210] think that the two specimens figured by Williamson as
carpellary discs are distinct organs, one being a staminate whorl and the
other a sterile infundibuliform organ. My own view is that both are of the
same nature and consist of microsporophylls.
preserved bracts. Diameter of axis, A, 3·5 cm. (From a specimen in
the Leeds Museum; nat. size.)
One of Williamson’s ‘carpellary discs’ has been shown by Nathorst to be
a verticil of microsporophylls bearing synangia, but both this author and
Lignier[1210] think that the two specimens figured by Williamson as
carpellary discs are distinct organs, one being a staminate whorl and the
other a sterile infundibuliform organ. My own view is that both are of the
same nature and consist of microsporophylls.
Page 473
Fig. 544. Williamsonia gigas. Portion of a flower showing the protective
bracts, the annular zone formed by numerous sterile sporophylls
and interseminal scales, and the large central cavity originally
occupied by the receptacle. (From a specimen in the Williamson
collection, Cambridge Botany School; nat. size.)
Fig. 544 represents the usual form in which the flowers of W. gigas are
found; it consists of linear bracts covered with hairs identical with those on
the peduncles shown in figs. 541–543; they surround a pyriform axis and
form what Williamson called an involucrum. The base of the fossil is
characterised by an annular zone formed of crowded, radially disposed,
narrow ridges now known to be casts of interseminal scales. At the outer
edge of this annular area impressions of the peltate ends of interseminal
scales are not infrequently preserved. Fig. 545 is a photograph of one of
Nathorst’s preparations showing the very great similarity between a
micropylar tube of W. gigas and the corresponding structures in
Cycadeoidea. The small micropylar tubes are surrounded by 5–6 polygonal
expanded apices of interseminal scales as in Cycadeoidea (fig. 515; cf. also
fig. 563), and the apex of each peltate distal end projects slightly as a
central papilla composed of more strongly cuticularised cells. In most
specimens the megasporophylls and interseminal scales (sterile
bracts, the annular zone formed by numerous sterile sporophylls
and interseminal scales, and the large central cavity originally
occupied by the receptacle. (From a specimen in the Williamson
collection, Cambridge Botany School; nat. size.)
Fig. 544 represents the usual form in which the flowers of W. gigas are
found; it consists of linear bracts covered with hairs identical with those on
the peduncles shown in figs. 541–543; they surround a pyriform axis and
form what Williamson called an involucrum. The base of the fossil is
characterised by an annular zone formed of crowded, radially disposed,
narrow ridges now known to be casts of interseminal scales. At the outer
edge of this annular area impressions of the peltate ends of interseminal
scales are not infrequently preserved. Fig. 545 is a photograph of one of
Nathorst’s preparations showing the very great similarity between a
micropylar tube of W. gigas and the corresponding structures in
Cycadeoidea. The small micropylar tubes are surrounded by 5–6 polygonal
expanded apices of interseminal scales as in Cycadeoidea (fig. 515; cf. also
fig. 563), and the apex of each peltate distal end projects slightly as a
central papilla composed of more strongly cuticularised cells. In most
specimens the megasporophylls and interseminal scales (sterile
Page 474
megasporophylls) are preserved only as an annular
zone at the base of the receptacle (fig. 548, as), but it
is clear from some specimens of W. gigas and other
species figured by Saporta[1211], Nathorst[1212], and
Krasser[1213] that originally the whole surface of the
pyriform axis was beset with these organs which fell
off, presumably, when the seeds had reached maturity.
No satisfactory examples of seeds have been found in
English specimens. Krasser has described some
specimens of Williamsonia from Jurassic rocks in
Sardinia to which he assigns some associated seeds,
but, as he admits, there is no proof of any connexion.
In some cases a funnel-like depression is seen at the
upper end of a strobilus of W. gigas (fig. 546, B, C, a)
identical in the occurrence of radially disposed ridges
Fig. 545.
with the annular zone at the base and due to the
Williamsonia
preservation of interseminal scales and aborted
gigas. Micropylar
megasporophylls in the upper part of the receptacle: in
tube. (After
this region also the impressions of polygonal apices of
Nathorst.)
the scales are sometimes found. The probability is that
while the greater part of the armour of scales and seeds was thrown off, at
the upper and lower end of the receptacle some sterile megasporophylls and
scales remained (fig. 548, as, dl).
zone at the base of the receptacle (fig. 548, as), but it
is clear from some specimens of W. gigas and other
species figured by Saporta[1211], Nathorst[1212], and
Krasser[1213] that originally the whole surface of the
pyriform axis was beset with these organs which fell
off, presumably, when the seeds had reached maturity.
No satisfactory examples of seeds have been found in
English specimens. Krasser has described some
specimens of Williamsonia from Jurassic rocks in
Sardinia to which he assigns some associated seeds,
but, as he admits, there is no proof of any connexion.
In some cases a funnel-like depression is seen at the
upper end of a strobilus of W. gigas (fig. 546, B, C, a)
identical in the occurrence of radially disposed ridges
Fig. 545.
with the annular zone at the base and due to the
Williamsonia
preservation of interseminal scales and aborted
gigas. Micropylar
megasporophylls in the upper part of the receptacle: in
tube. (After
this region also the impressions of polygonal apices of
Nathorst.)
the scales are sometimes found. The probability is that
while the greater part of the armour of scales and seeds was thrown off, at
the upper and lower end of the receptacle some sterile megasporophylls and
scales remained (fig. 548, as, dl).
Page 475
Fig. 546. Williamsonia gigas. A, apical portion of flower. B, cast of A; a,
persistent interseminal scales. C, flower in longitudinal section. C′,
interseminal scales from the base. (Williamson Collection, Botany
School, Cambridge.)
Williamson regarded the funnel-shaped depression as the impression of
the lower surface of a laterally expanded portion of the axis of the flower,
and to this expansion he gave the name lenticular disc (figs. 546, 547, a). It
persistent interseminal scales. C, flower in longitudinal section. C′,
interseminal scales from the base. (Williamson Collection, Botany
School, Cambridge.)
Williamson regarded the funnel-shaped depression as the impression of
the lower surface of a laterally expanded portion of the axis of the flower,
and to this expansion he gave the name lenticular disc (figs. 546, 547, a). It
Page 476
is, however, much more likely that the apparent extension of the axis is due
to the preservation of the sterile zone of armour which formed a cluster of
appendages, the impressions of which are seen on the sides of the funnel-
like depression, the receptacle being prolonged as a slender axis (fig. 547,
C). The next point to consider is the form of the axis beyond the level of the
collar of sterile armour. Williamson described the axis as spreading out to
form the lenticular disc and then prolonged as a narrow conical pyramidal
axis which is slightly extended horizontally immediately below a terminal
mammilla: the apical mammilla he designated the corona (fig. 547, C, r).
As already stated, the lenticular disc is probably not an expanded part of the
axis but the result of the preservation of a spreading mop-like cluster of
interseminal scales. This is the view expressed by Lignier[1214] who kindly
furnished the block from which fig. 548 is reproduced. The lower face of
Williamson’s lenticular disc is characterised by a series of spoke-like
radiating ridges (fig. 547, A′) between which are less distinct radially
disposed lines, and at the periphery there are impressions (fig. 547, A′′),
continuous with some of the radiating ridges, of the terminal shields of
interseminal scales. In fig. 547, drawn from one of the original specimens
described by Williamson, these features are shown at A′ and B: fig. A′
represents the circular area, which is at right-angles to the axis of the
flower, in surface-view. In the centre of this circular area is a depression
ending in a short papilla surrounded by a narrow basal rim: this feature is
shown on a cast of the specimen represented in fig. 547, B. In this case
Williamson’s corona is seated on a very short axis whereas in fig. 547, C,
also from one of Williamson’s specimens, the corona forms the apex of a
longer pyramidal axis. Wieland[1215] regarded the circular area seen in fig.
547, A, as the impression of the apical portion of a bisporangiate strobilus,
the ridges marking the edges of the incurved distal portions of
microsporophylls bent over the apex of the ovulate cone (cf. fig. 513), and
he interpreted the polygonal depressions at the periphery (fig. 547, A′′) as
those of sori, an interpretation entirely different from that of Lignier. The
latter author[1216] in part reasserted his opinion but modified it as regards the
meaning of the ridges on the circular area, agreeing so far with Wieland as
to consider them as having been formed by the folded-over rachises of
microsporophylls attached as a concrescent collar to the base of the ovulate
cone. This interpretation does not, however, explain the relation between
the radial striations on the circular area and the polygonal impressions at its
to the preservation of the sterile zone of armour which formed a cluster of
appendages, the impressions of which are seen on the sides of the funnel-
like depression, the receptacle being prolonged as a slender axis (fig. 547,
C). The next point to consider is the form of the axis beyond the level of the
collar of sterile armour. Williamson described the axis as spreading out to
form the lenticular disc and then prolonged as a narrow conical pyramidal
axis which is slightly extended horizontally immediately below a terminal
mammilla: the apical mammilla he designated the corona (fig. 547, C, r).
As already stated, the lenticular disc is probably not an expanded part of the
axis but the result of the preservation of a spreading mop-like cluster of
interseminal scales. This is the view expressed by Lignier[1214] who kindly
furnished the block from which fig. 548 is reproduced. The lower face of
Williamson’s lenticular disc is characterised by a series of spoke-like
radiating ridges (fig. 547, A′) between which are less distinct radially
disposed lines, and at the periphery there are impressions (fig. 547, A′′),
continuous with some of the radiating ridges, of the terminal shields of
interseminal scales. In fig. 547, drawn from one of the original specimens
described by Williamson, these features are shown at A′ and B: fig. A′
represents the circular area, which is at right-angles to the axis of the
flower, in surface-view. In the centre of this circular area is a depression
ending in a short papilla surrounded by a narrow basal rim: this feature is
shown on a cast of the specimen represented in fig. 547, B. In this case
Williamson’s corona is seated on a very short axis whereas in fig. 547, C,
also from one of Williamson’s specimens, the corona forms the apex of a
longer pyramidal axis. Wieland[1215] regarded the circular area seen in fig.
547, A, as the impression of the apical portion of a bisporangiate strobilus,
the ridges marking the edges of the incurved distal portions of
microsporophylls bent over the apex of the ovulate cone (cf. fig. 513), and
he interpreted the polygonal depressions at the periphery (fig. 547, A′′) as
those of sori, an interpretation entirely different from that of Lignier. The
latter author[1216] in part reasserted his opinion but modified it as regards the
meaning of the ridges on the circular area, agreeing so far with Wieland as
to consider them as having been formed by the folded-over rachises of
microsporophylls attached as a concrescent collar to the base of the ovulate
cone. This interpretation does not, however, explain the relation between
the radial striations on the circular area and the polygonal impressions at its
Page 477
periphery. Wieland still dissents from Lignier’s opinion and suggests that
the circular area has not been demonstrated to belong to the apical end of a
flower. Fig. 547 shows that its position is apical. Fig. 548 represents
Lignier’s view as to the nature of the rim surrounding the apical mammilla:
he suggested that several interseminal scales borne at the apical region of
the receptacle were concrescent and formed linear bracts the edges of which
are represented by the main ridges in fig. 547, A′. These concrescent scales
bent upwards and were closely applied to or perhaps concrescent with the
pyramidal axis and were then prolonged as a wide infundibuliform
apparatus (Williamson’s carpellary disc). This organ was, however, easily
detached, and the rim seen at r in fig. 547, C, represents its narrow broken
base. With this view I am in general agreement; but while Lignier regards
the funnel-like appendage as sterile and considers that similar organs, but
with a large central cavity at the base of the funnel, may have been
microsporophyll-discs which were borne below the ovulate strobilus in the
position occupied by the microsporophylls in Cycadeoidea (fig. 528)—my
inclination is to see in the terminal appendage a whorl of concrescent
microsporophylls. This view lacks the support of demonstration. It is
obvious from Williamson’s specimens and from others described by
Saporta, Nathorst, and Lignier that the receptacle of Williamsonia gigas was
not so simple in its termination as that of the flowers of Cycadeoidea. In
Cycadeoidea dacotensis Wieland showed that the apex of the receptacle
bore a tuft of long interseminal scales, and it is readily conceivable that
these apical appendages were still further developed in some Williamsonia
flowers to form a whorl of concrescent leaves borne on the prolonged apex
of the axis. There is little doubt as to the homology of interseminal scales
and microsporophylls, and there is no difficulty in supposing that while in
some flowers the foliar organs assumed the form of interseminal scales of
unusual length, in other species they became microsporophylls.
the circular area has not been demonstrated to belong to the apical end of a
flower. Fig. 547 shows that its position is apical. Fig. 548 represents
Lignier’s view as to the nature of the rim surrounding the apical mammilla:
he suggested that several interseminal scales borne at the apical region of
the receptacle were concrescent and formed linear bracts the edges of which
are represented by the main ridges in fig. 547, A′. These concrescent scales
bent upwards and were closely applied to or perhaps concrescent with the
pyramidal axis and were then prolonged as a wide infundibuliform
apparatus (Williamson’s carpellary disc). This organ was, however, easily
detached, and the rim seen at r in fig. 547, C, represents its narrow broken
base. With this view I am in general agreement; but while Lignier regards
the funnel-like appendage as sterile and considers that similar organs, but
with a large central cavity at the base of the funnel, may have been
microsporophyll-discs which were borne below the ovulate strobilus in the
position occupied by the microsporophylls in Cycadeoidea (fig. 528)—my
inclination is to see in the terminal appendage a whorl of concrescent
microsporophylls. This view lacks the support of demonstration. It is
obvious from Williamson’s specimens and from others described by
Saporta, Nathorst, and Lignier that the receptacle of Williamsonia gigas was
not so simple in its termination as that of the flowers of Cycadeoidea. In
Cycadeoidea dacotensis Wieland showed that the apex of the receptacle
bore a tuft of long interseminal scales, and it is readily conceivable that
these apical appendages were still further developed in some Williamsonia
flowers to form a whorl of concrescent leaves borne on the prolonged apex
of the axis. There is little doubt as to the homology of interseminal scales
and microsporophylls, and there is no difficulty in supposing that while in
some flowers the foliar organs assumed the form of interseminal scales of
unusual length, in other species they became microsporophylls.
Page 478
Fig. 547. Williamsonia gigas. A, flower in longitudinal section, showing,
especially on the left side, interseminal scales and megasporophylls
and a pyriform cavity representing the central axis (nat. size). A′,
the under surface of the apical region. A′′, interseminal scales from
A′. B, cast of A′. C, apical region of another specimen; a,
interseminal scales; c, column; r, ridge. (Williamson Collection,
Botany School, Cambridge.)
especially on the left side, interseminal scales and megasporophylls
and a pyriform cavity representing the central axis (nat. size). A′,
the under surface of the apical region. A′′, interseminal scales from
A′. B, cast of A′. C, apical region of another specimen; a,
interseminal scales; c, column; r, ridge. (Williamson Collection,
Botany School, Cambridge.)
Page 479
Fig. 548. Williamsonia gigas. Restoration showing an ovulate strobilus
bearing a terminal infundibuliform appendage. Lignier, to whom
the restoration is due, points out that the apical portion of the axis
at dl should be represented as straight and not, as in the figure,
horizontally expanded. bi, bracts; as, persistent interseminal scales
forming the annular zone; r, receptacle; cs, caducous
megasporophylls and interseminal scales; dl, persistent
interseminal scales, an extension of which formed the large funnel-
like appendage, at; ap, apex of the receptacle. (After Lignier.)
bearing a terminal infundibuliform appendage. Lignier, to whom
the restoration is due, points out that the apical portion of the axis
at dl should be represented as straight and not, as in the figure,
horizontally expanded. bi, bracts; as, persistent interseminal scales
forming the annular zone; r, receptacle; cs, caducous
megasporophylls and interseminal scales; dl, persistent
interseminal scales, an extension of which formed the large funnel-
like appendage, at; ap, apex of the receptacle. (After Lignier.)
Page 480
It is noteworthy that the radiating ridges on the circular area shown in fig.
547, A′, agree in position and approximately at least in number with those
on the sides of the cupular disc of the microsporophyll-verticil of
Williamsonia whitbiensis[1217]. Nathorst describes a specimen seen in a
private collection in which an infundibuliform appendage appeared to be
preserved in situ at the apex of a flower of Williamsonia gigas (cf. fig. 548,
at). Thomas[1218], in his description of Williamsoniella, compares the radial
ridges on the apical sterile portion of a flower of Williamsonia gigas to the
ridges on his Williamsoniella which are formed by the tips of infolded
microsporophylls.
Fig. 549. Williamsonia gigas. A, diagrammatic drawing showing the
position of the synangia, at S, and part of the staminate disc. B, a
single synangium; × 6. (After Thomas.)
Williamsonia gigas (Microsporophylls).
547, A′, agree in position and approximately at least in number with those
on the sides of the cupular disc of the microsporophyll-verticil of
Williamsonia whitbiensis[1217]. Nathorst describes a specimen seen in a
private collection in which an infundibuliform appendage appeared to be
preserved in situ at the apex of a flower of Williamsonia gigas (cf. fig. 548,
at). Thomas[1218], in his description of Williamsoniella, compares the radial
ridges on the apical sterile portion of a flower of Williamsonia gigas to the
ridges on his Williamsoniella which are formed by the tips of infolded
microsporophylls.
Fig. 549. Williamsonia gigas. A, diagrammatic drawing showing the
position of the synangia, at S, and part of the staminate disc. B, a
single synangium; × 6. (After Thomas.)
Williamsonia gigas (Microsporophylls).
Page 481
In the course of an examination of the Williamsonia specimens (from
Yorkshire) in Paris in July of last year (1914) Mr Thomas[1219] found a
specimen previously overlooked, which is undoubtedly either a male flower
or, as I am inclined to think, the staminate disc of a bisporangiate flower of
Williamsonia gigas. The nature of the matrix shows that it came from the
neighbourhood of Whitby. It consists of an urn-shaped organ formed of the
concrescent bases of 18–20 microsporophylls each 7–8 mm. wide; the cup
is 5–6 cm. broad, the base being torn but tapered (fig. 549) as though
originally prolonged downwards into a stalk as in W. spectabilis. Along the
middle line of each sporophyll is a series of depressions, probably the same
in nature as those on W. whitbiensis described by Nathorst, though it is not
clear whether, in this case at least, they represent aborted synangia. Some
reniform synangia (fig. 549, B) occur in the rock just above the cup. The
sporophylls spread outwards from the base and then curve inwards, bending
outwards again as they become free. A portion of a microsporophyll is
shown in fig. 550 bearing segments projecting inwards as in W. spectabilis
(fig. 551). This specimen, which occurs in association with female flowers,
is regarded by Mr Thomas as part of a unisexual flower. He discusses the
possibility of its connexion with an ovulate receptacle and expresses the
opinion that if it were borne at the upper end of a bisporangiate flower the
whole would be top-heavy and the arrangement uneconomical. On the other
hand if, as suggested on page 434, the flowers were bisexual the staminate
disc, which reached maturity before the ovules, may have been thrown off,
as in Cycadeoidea, before the seeds were ripe. The form of the disc
resembles that of the Indian specimen described on another page as
Williamsonia sp., cf. W. setosa Nath.; it does not, I venture to think, afford
an argument against the view that the microsporophyll-cup of some
Williamsonia flowers was attached near the apex of the receptacle and was
formed of modified foliar organs homologous with those which, in the
ovulate portion of the flower, constitute the interseminal scales and
megasporophylls.
A further consideration of the microsporophylls of Williamsonia will be
found in a later section of this chapter.
Williamsonia spectabilis Nathorst.
Yorkshire) in Paris in July of last year (1914) Mr Thomas[1219] found a
specimen previously overlooked, which is undoubtedly either a male flower
or, as I am inclined to think, the staminate disc of a bisporangiate flower of
Williamsonia gigas. The nature of the matrix shows that it came from the
neighbourhood of Whitby. It consists of an urn-shaped organ formed of the
concrescent bases of 18–20 microsporophylls each 7–8 mm. wide; the cup
is 5–6 cm. broad, the base being torn but tapered (fig. 549) as though
originally prolonged downwards into a stalk as in W. spectabilis. Along the
middle line of each sporophyll is a series of depressions, probably the same
in nature as those on W. whitbiensis described by Nathorst, though it is not
clear whether, in this case at least, they represent aborted synangia. Some
reniform synangia (fig. 549, B) occur in the rock just above the cup. The
sporophylls spread outwards from the base and then curve inwards, bending
outwards again as they become free. A portion of a microsporophyll is
shown in fig. 550 bearing segments projecting inwards as in W. spectabilis
(fig. 551). This specimen, which occurs in association with female flowers,
is regarded by Mr Thomas as part of a unisexual flower. He discusses the
possibility of its connexion with an ovulate receptacle and expresses the
opinion that if it were borne at the upper end of a bisporangiate flower the
whole would be top-heavy and the arrangement uneconomical. On the other
hand if, as suggested on page 434, the flowers were bisexual the staminate
disc, which reached maturity before the ovules, may have been thrown off,
as in Cycadeoidea, before the seeds were ripe. The form of the disc
resembles that of the Indian specimen described on another page as
Williamsonia sp., cf. W. setosa Nath.; it does not, I venture to think, afford
an argument against the view that the microsporophyll-cup of some
Williamsonia flowers was attached near the apex of the receptacle and was
formed of modified foliar organs homologous with those which, in the
ovulate portion of the flower, constitute the interseminal scales and
megasporophylls.
A further consideration of the microsporophylls of Williamsonia will be
found in a later section of this chapter.
Williamsonia spectabilis Nathorst.
Page 482
This species[1220], the first example of
undoubted microspore-bearing organs referred
to Williamsonia, was founded on material
discovered by Prof. Nathorst in the Lower
Estuarine series of Whitby; it has also been
obtained from beds of the same age at Marske
in the Cleveland district of Yorkshire[1221].
Williamsonia spectabilis, though indubitably a
male organ, has not been found attached to a
stem, and there is no decisive evidence as to its
connexion with a particular species of frond.
Nathorst believes that it belongs to the plant
which bore the leaves known as Ptilophyllum Fig. 550. Williamsonia
pecten, an opinion based chiefly on association. gigas. Side-view of an
The more complete specimens consist of a incomplete staminate
broad funnel-shaped organ prolonged below disc showing the basal
into a slender stalk and divided at the margin cup torn at the lower
into several linear-lanceolate segments end and part of one of
(microsporophylls) the apices of which were the free
rolled inwards like young fern-fronds (figs. 551, microsporophylls.
552). The synangia agree closely in form and in (Diagrammatic
such structural features as can be made out from drawing, after
cuticular preparations with those described by Thomas; nat. size.)
Wieland in American species of Cycadeoidea; they are slightly reniform, 5–
6 mm. long and 2 mm. broad and divided into several loculi by transverse
partitions (fig. 552). The microspores, 58–65µ in length, are rather narrow,
ovate and very similar to those described by Solms-Laubach[1222] in
Cycadeoidea etrusca. The synangia are attached in two rows to slender
lateral segments which appear to be given off from the upper face near the
median line of the broad linear sporophylls (fig. 565, A). Nathorst points
out that the position of the fertile pinnae brings the sporophylls into close
relation with the vegetative fronds of Ptilophyllum pecten and other
Cycadean fronds in which the pinnae are attached to the upper face of the
rachis. While the longer pinnae in the middle portion of a sporophyll bear
several synangia, those near the base and apex are shorter and, in the
proximal region nearer the broad cup formed by the coherent bases of the
sporophylls, occur singly, thus approaching the condition characteristic of
undoubted microspore-bearing organs referred
to Williamsonia, was founded on material
discovered by Prof. Nathorst in the Lower
Estuarine series of Whitby; it has also been
obtained from beds of the same age at Marske
in the Cleveland district of Yorkshire[1221].
Williamsonia spectabilis, though indubitably a
male organ, has not been found attached to a
stem, and there is no decisive evidence as to its
connexion with a particular species of frond.
Nathorst believes that it belongs to the plant
which bore the leaves known as Ptilophyllum Fig. 550. Williamsonia
pecten, an opinion based chiefly on association. gigas. Side-view of an
The more complete specimens consist of a incomplete staminate
broad funnel-shaped organ prolonged below disc showing the basal
into a slender stalk and divided at the margin cup torn at the lower
into several linear-lanceolate segments end and part of one of
(microsporophylls) the apices of which were the free
rolled inwards like young fern-fronds (figs. 551, microsporophylls.
552). The synangia agree closely in form and in (Diagrammatic
such structural features as can be made out from drawing, after
cuticular preparations with those described by Thomas; nat. size.)
Wieland in American species of Cycadeoidea; they are slightly reniform, 5–
6 mm. long and 2 mm. broad and divided into several loculi by transverse
partitions (fig. 552). The microspores, 58–65µ in length, are rather narrow,
ovate and very similar to those described by Solms-Laubach[1222] in
Cycadeoidea etrusca. The synangia are attached in two rows to slender
lateral segments which appear to be given off from the upper face near the
median line of the broad linear sporophylls (fig. 565, A). Nathorst points
out that the position of the fertile pinnae brings the sporophylls into close
relation with the vegetative fronds of Ptilophyllum pecten and other
Cycadean fronds in which the pinnae are attached to the upper face of the
rachis. While the longer pinnae in the middle portion of a sporophyll bear
several synangia, those near the base and apex are shorter and, in the
proximal region nearer the broad cup formed by the coherent bases of the
sporophylls, occur singly, thus approaching the condition characteristic of
Page 483
W. whitbiensis (fig. 565, B) in which they are sessile on the simple
microsporophylls. It is noteworthy that in some specimens figured by
Nathorst there is a tendency of the lower part of the cup to break away from
the coherent bases of the sporophylls (fig. 551)[1223], and it is not unlikely
that some of the impressions described as infundibuliform appendages are
incomplete examples of Williamsonia spectabilis.
Fig. 551. Williamsonia spectabilis and leaves of Ptilophyllum pecten.
(After Nathorst; ⅚ nat. size.)
microsporophylls. It is noteworthy that in some specimens figured by
Nathorst there is a tendency of the lower part of the cup to break away from
the coherent bases of the sporophylls (fig. 551)[1223], and it is not unlikely
that some of the impressions described as infundibuliform appendages are
incomplete examples of Williamsonia spectabilis.
Fig. 551. Williamsonia spectabilis and leaves of Ptilophyllum pecten.
(After Nathorst; ⅚ nat. size.)
Page 484
Fig. 552. Williamsonia spectabilis. Restoration of an almost mature
male flower. (After Thomas; approximately nat. size.)
Fig. 553. Williamsonia Leckenbyi. Surface-view and in section.
(Restoration after Nathorst.)
Williamsonia Leckenbyi Nathorst.
This species, founded on specimens from the Middle Estuarine beds
exposed on the Yorkshire coast at Cloughton Wyke[1224], is characterised by
male flower. (After Thomas; approximately nat. size.)
Fig. 553. Williamsonia Leckenbyi. Surface-view and in section.
(Restoration after Nathorst.)
Williamsonia Leckenbyi Nathorst.
This species, founded on specimens from the Middle Estuarine beds
exposed on the Yorkshire coast at Cloughton Wyke[1224], is characterised by
Page 485
the almost spherical form of the strobilus, 4·5–5 cm. in diameter. The
relatively small receptacle is covered by a thick mass of megasporophylls
and interseminal scales except in the lower part which bears only sterile
scales. Nathorst believes that the seeds were very small, but no undoubted
examples have been found. A specimen in the British Museum, figured in
1900[1225], shows the surface-view of an impression of the base of the
flower; a small circular raised boss occupies the centre—the scar of the
receptacle—and surrounding this is a reticulum formed by the impression
of the distal ends of the interseminal scales. The uniform nature of the
reticulum, the meshes of which are all of the same type, shows that in the
basal region of the flower the organs borne on the receptacle were all sterile
as in Cycadeoidea (Bennettites) Morierei. Except in the smaller diameter of
the receptacle this specimen is practically identical with that of
Williamsonia Carruthersi Sew. reproduced in fig. 559. The form of the
strobilus is shown in Nathorst’s restoration[1226] represented in fig. 553. The
interseminal scales have broad peltate distal ends characterised by a patch
of lighter and thinner-walled cells at the apex (fig. 554); the micropylar
tubes are slightly expanded at the summit and their epidermal cells are
papillose as in Williamsonia scotica (cf. fig. 563, B). Nathorst in 1909
adopted the name Williamsonia pecten Carr.[1227] for the specimens
originally referred to W. Leckenbyi as well as for microsporophylls that he
believed to belong to the same plant as the ovulate strobili: but in a later
paper[1228] he restricts the name Williamsonia pecten to the male strobili,
reserving W. Leckenbyi for the ovulate forms, as there is no proof that both
were borne on the same plant. From the evidence at present available it is
reasonable to regard W. Leckenbyi as a unisexual flower. In all probability
the fronds known as Ptilophyllum pecten are the foliage of the parent-plant
of W. Leckenbyi, though in the absence of proof it is advisable to retain both
names.
relatively small receptacle is covered by a thick mass of megasporophylls
and interseminal scales except in the lower part which bears only sterile
scales. Nathorst believes that the seeds were very small, but no undoubted
examples have been found. A specimen in the British Museum, figured in
1900[1225], shows the surface-view of an impression of the base of the
flower; a small circular raised boss occupies the centre—the scar of the
receptacle—and surrounding this is a reticulum formed by the impression
of the distal ends of the interseminal scales. The uniform nature of the
reticulum, the meshes of which are all of the same type, shows that in the
basal region of the flower the organs borne on the receptacle were all sterile
as in Cycadeoidea (Bennettites) Morierei. Except in the smaller diameter of
the receptacle this specimen is practically identical with that of
Williamsonia Carruthersi Sew. reproduced in fig. 559. The form of the
strobilus is shown in Nathorst’s restoration[1226] represented in fig. 553. The
interseminal scales have broad peltate distal ends characterised by a patch
of lighter and thinner-walled cells at the apex (fig. 554); the micropylar
tubes are slightly expanded at the summit and their epidermal cells are
papillose as in Williamsonia scotica (cf. fig. 563, B). Nathorst in 1909
adopted the name Williamsonia pecten Carr.[1227] for the specimens
originally referred to W. Leckenbyi as well as for microsporophylls that he
believed to belong to the same plant as the ovulate strobili: but in a later
paper[1228] he restricts the name Williamsonia pecten to the male strobili,
reserving W. Leckenbyi for the ovulate forms, as there is no proof that both
were borne on the same plant. From the evidence at present available it is
reasonable to regard W. Leckenbyi as a unisexual flower. In all probability
the fronds known as Ptilophyllum pecten are the foliage of the parent-plant
of W. Leckenbyi, though in the absence of proof it is advisable to retain both
names.
Page 486
Fig. 554. Williamsonia Leckenbyi. Micropyle and interseminal scale.
(After Nathorst.)
Williamsonia whitbiensis Nathorst.
Under this name Nathorst[1229] described some interesting specimens of
microsporophylls formerly attributed by him to Williamsonia pecten, but
the discovery of additional material led him to distinguish the Whitby
(Lower Estuarine) fossils as W. whitbiensis, retaining the name W. pecten
for the type originally figured by Leckenby[1230] from the Middle Estuarine
series at Cloughton Wyke on the Yorkshire coast. In the type-specimen, 8–
10 cm. in diameter, there are 15 linear segments coalescent basally into a
thick cup differing from that of W. spectabilis in the absence of a stalk (figs.
555, 556). A more important distinctive feature is the production of
synangia on the simple sporophylls (figs. 556, B; 565, B) and not on special
fertile segments as in W. spectabilis (fig. 552). The inner face of each
sporophyll, as seen in impressions, shows two regular rows of small
depressions, one on each side of the median line; these become gradually
smaller towards the base of the cup-like disc (figs. 555, 556). On the actual
carbonised surface of the inner face of the cup small and transversely
elongated projections take the place of the depressions and these show the
same decrease in size when traced from the free segments to the cupular
organ. Nathorst obtained microspores only from the larger projections and
none from the smaller, a circumstance which may indicate that only the
upper and larger synangia were fully developed[1231].
(After Nathorst.)
Williamsonia whitbiensis Nathorst.
Under this name Nathorst[1229] described some interesting specimens of
microsporophylls formerly attributed by him to Williamsonia pecten, but
the discovery of additional material led him to distinguish the Whitby
(Lower Estuarine) fossils as W. whitbiensis, retaining the name W. pecten
for the type originally figured by Leckenby[1230] from the Middle Estuarine
series at Cloughton Wyke on the Yorkshire coast. In the type-specimen, 8–
10 cm. in diameter, there are 15 linear segments coalescent basally into a
thick cup differing from that of W. spectabilis in the absence of a stalk (figs.
555, 556). A more important distinctive feature is the production of
synangia on the simple sporophylls (figs. 556, B; 565, B) and not on special
fertile segments as in W. spectabilis (fig. 552). The inner face of each
sporophyll, as seen in impressions, shows two regular rows of small
depressions, one on each side of the median line; these become gradually
smaller towards the base of the cup-like disc (figs. 555, 556). On the actual
carbonised surface of the inner face of the cup small and transversely
elongated projections take the place of the depressions and these show the
same decrease in size when traced from the free segments to the cupular
organ. Nathorst obtained microspores only from the larger projections and
none from the smaller, a circumstance which may indicate that only the
upper and larger synangia were fully developed[1231].
Page 487
Fig. 555. Williamsonia whitbiensis. (After Nathorst; ⅚ nat. size.)
Fig. 556. Williamsonia whitbiensis. A, male flower. B, sporophyll with
synangia. (After Nathorst.)
This species is especially interesting as throwing light on the nature of
one of the specimens (from the Whitby Museum) figured by Williamson as
a ‘carpellary disc[1232]’: the ‘seeds’ of Williamson are no doubt, as Nathorst
believes, synangia, while the smaller pairs of markings figured by
Williamson represent rudimentary synangia and not ‘abortive ovules.’
Though the specific identity of Williamson’s specimen and Williamsonia
Fig. 556. Williamsonia whitbiensis. A, male flower. B, sporophyll with
synangia. (After Nathorst.)
This species is especially interesting as throwing light on the nature of
one of the specimens (from the Whitby Museum) figured by Williamson as
a ‘carpellary disc[1232]’: the ‘seeds’ of Williamson are no doubt, as Nathorst
believes, synangia, while the smaller pairs of markings figured by
Williamson represent rudimentary synangia and not ‘abortive ovules.’
Though the specific identity of Williamson’s specimen and Williamsonia
Page 488
whitbiensis is not certain, the latter is undoubtedly a closely allied form of a
microsporophyll-verticil. A specimen figured in 1900 as a flower of
Williamsonia pecten[1233], designated by Nathorst Williamsonia sp., is a very
similar if not an identical type; it consists of a fairly deep basal cup the
surface of which is characterised by the presence of several regular ridges
between which are pairs of small depressions containing carbonaceous
matter. In the light of Nathorst’s researches it is clear that this is an
incomplete example of a whorl of microsporophylls. The base of the disc is
incomplete, but it is certain from the small size of the basal hole with torn
edges that the cup could not have been attached to the base of a receptacle
as are the microsporophylls in Wieland’s bisporangiate flowers of
Cycadeoidea. The specimens referred by Nathorst to Williamsonia
pecten[1234] (Leck. ex parte) are similar to those described as W. whitbiensis,
but differ in the texture of the cup and in the degree of cuticularisation of
the synangial walls. The synangia of W. pecten are of the usual reniform
type and multicellular as in W. spectabilis.
Williamsonia setosa Nathorst.
The distinguishing features of this species[1235], founded on material
collected by Dr Halle from Lower Estuarine beds at Whitby, are (i) the
greater number of linear sporophylls which bear numerous bristles or stout
hairs, (ii) the loose coherence of the contracted proximal portion of the
linear segments, and (iii) a narrower basal disc in place of the deeper cup of
other species. One of the specimens referred to this species, formerly
regarded by Nathorst as an infundibuliform organ of an ovulate strobilus of
W. gigas[1236], bears a striking resemblance to an Indian fossil described by
Feistmantel from India[1237].
Indian species of Williamsonia (Flowers).
Several specimens of Williamsonia have been described from the
Rajmahal and other Jurassic series in India, some of which exhibit a close
agreement with Williamsonia gigas. It is, however, noteworthy that no
fronds of the Zamites gigas type have been discovered in Indian beds; on
the other hand the association of fronds of the same type as Ptilophyllum
pecten with Williamsonian strobili is significant, as also the occurrence of
microsporophyll-verticil. A specimen figured in 1900 as a flower of
Williamsonia pecten[1233], designated by Nathorst Williamsonia sp., is a very
similar if not an identical type; it consists of a fairly deep basal cup the
surface of which is characterised by the presence of several regular ridges
between which are pairs of small depressions containing carbonaceous
matter. In the light of Nathorst’s researches it is clear that this is an
incomplete example of a whorl of microsporophylls. The base of the disc is
incomplete, but it is certain from the small size of the basal hole with torn
edges that the cup could not have been attached to the base of a receptacle
as are the microsporophylls in Wieland’s bisporangiate flowers of
Cycadeoidea. The specimens referred by Nathorst to Williamsonia
pecten[1234] (Leck. ex parte) are similar to those described as W. whitbiensis,
but differ in the texture of the cup and in the degree of cuticularisation of
the synangial walls. The synangia of W. pecten are of the usual reniform
type and multicellular as in W. spectabilis.
Williamsonia setosa Nathorst.
The distinguishing features of this species[1235], founded on material
collected by Dr Halle from Lower Estuarine beds at Whitby, are (i) the
greater number of linear sporophylls which bear numerous bristles or stout
hairs, (ii) the loose coherence of the contracted proximal portion of the
linear segments, and (iii) a narrower basal disc in place of the deeper cup of
other species. One of the specimens referred to this species, formerly
regarded by Nathorst as an infundibuliform organ of an ovulate strobilus of
W. gigas[1236], bears a striking resemblance to an Indian fossil described by
Feistmantel from India[1237].
Indian species of Williamsonia (Flowers).
Several specimens of Williamsonia have been described from the
Rajmahal and other Jurassic series in India, some of which exhibit a close
agreement with Williamsonia gigas. It is, however, noteworthy that no
fronds of the Zamites gigas type have been discovered in Indian beds; on
the other hand the association of fronds of the same type as Ptilophyllum
pecten with Williamsonian strobili is significant, as also the occurrence of
Page 489
stems apparently identical in surface-features with English and Mexican
species.
Williamsonia sp.
Oldham and Morris[1238] figured a specimen from the Rajmahal Hills
consisting of a circular disc enclosed by a zone of ‘closely packed tubes,’
the basal portion of an ovulate Williamsonia strobilus, which they regarded
as a pressed mass of young leaves ‘probably related to Palaeozamia’
[Ptilophyllum]. The figured specimen shows that the radially disposed
‘tubes’ surrounding the circular area are interseminal scales some of which
are seen at the periphery in surface-view as small polygonal areas as in
English specimens. Feistmantel[1239] refigured this specimen and referred it
to Williamsonia gigas though on insufficient grounds. To the same species
Feistmantel[1240] assigns two other specimens from the Rajmahal series, one
of which consists of several narrow linear bracts partially enclosing a
strobilus with a portion of the annular zone at the base in which the
seminiferous scales are shown in longitudinal-view and a few in apical-
view.
species.
Williamsonia sp.
Oldham and Morris[1238] figured a specimen from the Rajmahal Hills
consisting of a circular disc enclosed by a zone of ‘closely packed tubes,’
the basal portion of an ovulate Williamsonia strobilus, which they regarded
as a pressed mass of young leaves ‘probably related to Palaeozamia’
[Ptilophyllum]. The figured specimen shows that the radially disposed
‘tubes’ surrounding the circular area are interseminal scales some of which
are seen at the periphery in surface-view as small polygonal areas as in
English specimens. Feistmantel[1239] refigured this specimen and referred it
to Williamsonia gigas though on insufficient grounds. To the same species
Feistmantel[1240] assigns two other specimens from the Rajmahal series, one
of which consists of several narrow linear bracts partially enclosing a
strobilus with a portion of the annular zone at the base in which the
seminiferous scales are shown in longitudinal-view and a few in apical-
view.
Page 490
Fig. 557. Williamsonia sp. A, whorl of microsporophylls; s, synangia (?).
C, side-view of the basal portion of A. B, part of a microsporophyll
enlarged. (Indian Geological Survey; A, nat. size.)
Williamsonia sp. cf. Williamsonia setosa Nathorst.
A third example from the same locality (fig. 557) is described by
Feistmantel[1241] as part of one of Williamson’s ‘carpellary discs[1242],’ a
comparison that is fully justified. The accompanying drawing has been
carefully made from the actual specimen: portions of 10 very hairy bracts
radiate in a horizontal plane from a continuous lamina with a wrinkled and
C, side-view of the basal portion of A. B, part of a microsporophyll
enlarged. (Indian Geological Survey; A, nat. size.)
Williamsonia sp. cf. Williamsonia setosa Nathorst.
A third example from the same locality (fig. 557) is described by
Feistmantel[1241] as part of one of Williamson’s ‘carpellary discs[1242],’ a
comparison that is fully justified. The accompanying drawing has been
carefully made from the actual specimen: portions of 10 very hairy bracts
radiate in a horizontal plane from a continuous lamina with a wrinkled and
Page 491
ridged surface bent sharply back at right-angles to the bracts and forming a
double curve as seen in the sectional view (fig. 557, C). The form assumed
by the vertical part of the disc is, I believe, the result of compression.
Wieland[1243] regards this fossil as a whorl of microsporophylls originally
attached to the lower portion of the receptacle of a bisexual flower. Close to
the edge of one of the bracts is an imperfectly preserved structure (fig. 557,
B, s) which may represent two alternately arranged rows of synangia
belonging to one of the hairy bracts; but we have no evidence as to the
position of the microsporophylls on the flower-axis. The central space
enclosed by the crushed concrescent portion of the disc is large enough to
have embraced a receptacle but, on the other hand, the portion preserved
may have broken off from a proximal cup like that of W. spectabilis[1244],
which, as Nathorst’s specimens show, is sometimes broken across near the
upper edge of the basal funnel. This specimen is spoken of by Feistmantel
as Williamsonia gigas. It is impossible to say whether these Rajmahal
specimens belong to one species, and they are therefore provisionally
designated Williamsonia sp. and Williamsonia sp. cf. W. setosa.
Williamsonia microps Feistmantel.
This species is based on a compressed ovate strobilus surrounded by
linear bracts and a portion of the cylindrical axis[1245]. It is possible that this
smaller, bud-like, specimen may be a younger example of the species
referred by Feistmantel to Williamsonia gigas.
Williamsonia Blandfordi Feistmantel.
Founded on a small strobilus enclosed by linear bracts, from the Jurassic
rocks of Cutch[1246], very similar to Williamsonia pecten; as seen in fig. 558,
drawn from the original specimen, the flower is associated with a
Ptilophyllum frond indistinguishable from some examples of Ptilophyllum
pecten.
Williamsonia indica, sp. nov.
This name is proposed for some imperfect specimens described by
Feistmantel from the Godaveri district and named by him Williamsonia sp.
cf. Williamsonia gigas[1247]. They differ from Williamsonia gigas in the
larger size of the bracts which reach a length of 13 cm. and may be
double curve as seen in the sectional view (fig. 557, C). The form assumed
by the vertical part of the disc is, I believe, the result of compression.
Wieland[1243] regards this fossil as a whorl of microsporophylls originally
attached to the lower portion of the receptacle of a bisexual flower. Close to
the edge of one of the bracts is an imperfectly preserved structure (fig. 557,
B, s) which may represent two alternately arranged rows of synangia
belonging to one of the hairy bracts; but we have no evidence as to the
position of the microsporophylls on the flower-axis. The central space
enclosed by the crushed concrescent portion of the disc is large enough to
have embraced a receptacle but, on the other hand, the portion preserved
may have broken off from a proximal cup like that of W. spectabilis[1244],
which, as Nathorst’s specimens show, is sometimes broken across near the
upper edge of the basal funnel. This specimen is spoken of by Feistmantel
as Williamsonia gigas. It is impossible to say whether these Rajmahal
specimens belong to one species, and they are therefore provisionally
designated Williamsonia sp. and Williamsonia sp. cf. W. setosa.
Williamsonia microps Feistmantel.
This species is based on a compressed ovate strobilus surrounded by
linear bracts and a portion of the cylindrical axis[1245]. It is possible that this
smaller, bud-like, specimen may be a younger example of the species
referred by Feistmantel to Williamsonia gigas.
Williamsonia Blandfordi Feistmantel.
Founded on a small strobilus enclosed by linear bracts, from the Jurassic
rocks of Cutch[1246], very similar to Williamsonia pecten; as seen in fig. 558,
drawn from the original specimen, the flower is associated with a
Ptilophyllum frond indistinguishable from some examples of Ptilophyllum
pecten.
Williamsonia indica, sp. nov.
This name is proposed for some imperfect specimens described by
Feistmantel from the Godaveri district and named by him Williamsonia sp.
cf. Williamsonia gigas[1247]. They differ from Williamsonia gigas in the
larger size of the bracts which reach a length of 13 cm. and may be
Page 492
compared with those of a large specimen recorded from Mexico as
Williamsonia Cuauhtemoc[1248].
Fig. 558. Williamsonia Blandfordi and Ptilophyllum frond.
(Geological Survey of India; nat. size.)
It is almost certain that some at least of the Indian flowers were borne on
stems with the foliage known as Ptilophyllum acutifolium, an inference
based not only on the almost constant association of flowers and fronds but
also on the juxtaposition of both kinds of organs with stems precisely
similar to those described from England and Mexico. Though none of the
specimens are sufficiently well preserved to afford much information as to
structural features, Miss Bancroft[1249] has shown that the bracts of one of
the examples assigned by Feistmantel to W. gigas are similar anatomically
to those of Williamsonia scotica and are clothed with simple hairs. The
important point is the very close correspondence between the Indian and
English types of Williamsonia, as regards flowers, fronds, and stems.
Williamsonia Cuauhtemoc[1248].
Fig. 558. Williamsonia Blandfordi and Ptilophyllum frond.
(Geological Survey of India; nat. size.)
It is almost certain that some at least of the Indian flowers were borne on
stems with the foliage known as Ptilophyllum acutifolium, an inference
based not only on the almost constant association of flowers and fronds but
also on the juxtaposition of both kinds of organs with stems precisely
similar to those described from England and Mexico. Though none of the
specimens are sufficiently well preserved to afford much information as to
structural features, Miss Bancroft[1249] has shown that the bracts of one of
the examples assigned by Feistmantel to W. gigas are similar anatomically
to those of Williamsonia scotica and are clothed with simple hairs. The
important point is the very close correspondence between the Indian and
English types of Williamsonia, as regards flowers, fronds, and stems.
Page 493
Fig. 559. Williamsonia Carruthersi. A, unexpanded flower. A′, the
reticulate lamellae projecting from the face of a bract. B, the basal
portion of a larger and expanded flower showing the impressions
of the interseminal scales and the base of the receptacle. (British
Museum, A, V. 3177; B, V. 3201.)
British Specimens.
Williamsonia Carruthersi Seward.
This species was founded on several specimens from Wealden beds on
the Sussex coast none of which afford information as to anatomical
structure[1250]. It is not improbable that more than one species is represented.
The ovulate cone, 6 cm. long, is surrounded by several linear bracts (fig.
559, A) and in shape resembles Bennettites Morierei Lign.; the bracts are
broken across near the base, as is frequently the case in Williamsonia gigas,
exposing an annular zone formed by persistent interseminal scales. From
the inner face of some of the bracts project slender radiating plates (fig.
559, A′) which no doubt mark the boundary of the superficial and relatively
reticulate lamellae projecting from the face of a bract. B, the basal
portion of a larger and expanded flower showing the impressions
of the interseminal scales and the base of the receptacle. (British
Museum, A, V. 3177; B, V. 3201.)
British Specimens.
Williamsonia Carruthersi Seward.
This species was founded on several specimens from Wealden beds on
the Sussex coast none of which afford information as to anatomical
structure[1250]. It is not improbable that more than one species is represented.
The ovulate cone, 6 cm. long, is surrounded by several linear bracts (fig.
559, A) and in shape resembles Bennettites Morierei Lign.; the bracts are
broken across near the base, as is frequently the case in Williamsonia gigas,
exposing an annular zone formed by persistent interseminal scales. From
the inner face of some of the bracts project slender radiating plates (fig.
559, A′) which no doubt mark the boundary of the superficial and relatively
Page 494
large interseminal scales, like those forming the so-called pericarp in
Bennettites Gibsonianus. The receptacle appears to have been conical, a
feature recalling Bennettites rather than Williamsonia. The saucer-like
impression shown in fig. 559, B, is practically identical with the
corresponding portion of Williamsonia Leckenbyi: the centre is occupied by
a raised area, the basal part of the receptacle, on which a series of peripheral
prominences represents the vascular strands; the sides of the saucer show
very clearly the reticulum formed by the distal ends of interseminal scales.
One reason for assigning this species to Williamsonia rather than to
Bennettites (or Cycadeoidea) is the occurrence in the same bed of a
peduncle 12 cm. long and 3 cm. broad which probably belonged to the
parent-plant of the cone. The surface of the peduncle shows spirally
disposed scars of bracts crowded at the distal end and more widely
separated in the lower portion.
Williamsonia Bucklandi (Unger).
In 1837 Buckland[1251] gave an account of a ‘unique and beautiful fossil
fruit’ from Inferior Oolite beds at Charmouth in Dorsetshire and stated that
the type-specimen was in the Oxford Museum. Professor Sollas kindly
searched for the specimen some years ago but without success. Buckland
considered that the fruit was related to the Pandanaceae and described it as
follows: ‘The size of this fruit is that of a large orange, its surface is
occupied by a stellated covering or epicarpium, composed of hexagonal
tubercles, forming the summits of cells, which occupy the entire
circumference of the fruit. Within each cell is contained a single seed,
resembling a small grain of rice more or less compressed, and usually
hexagonal. When the epicarpium is removed, the points of the seeds are
seen, thickly studded over the surface of the fruit. The bases of the cells are
separated from the receptacle by a congeries of foot-stalks formed of a
dense mass of fibres, resembling the fibres beneath the base of the seeds of
the modern Pandanus.’ At the suggestion of Robert Brown he called the
‘fruit’ Podocarya, the specific name Bucklandi being afterwards given by
Unger[1252]. Brongniart[1253] called attention to the resemblance of Buckland’s
specimen to Williamsonia, and that name has been adopted by Saporta[1254],
Nathorst, and other authors[1255]. Sowerby’s drawings illustrating the original
description, one of which is reproduced in fig. 560, show that this unusually
fine specimen is an ovulate Bennettitean strobilus very similar in its thick
Bennettites Gibsonianus. The receptacle appears to have been conical, a
feature recalling Bennettites rather than Williamsonia. The saucer-like
impression shown in fig. 559, B, is practically identical with the
corresponding portion of Williamsonia Leckenbyi: the centre is occupied by
a raised area, the basal part of the receptacle, on which a series of peripheral
prominences represents the vascular strands; the sides of the saucer show
very clearly the reticulum formed by the distal ends of interseminal scales.
One reason for assigning this species to Williamsonia rather than to
Bennettites (or Cycadeoidea) is the occurrence in the same bed of a
peduncle 12 cm. long and 3 cm. broad which probably belonged to the
parent-plant of the cone. The surface of the peduncle shows spirally
disposed scars of bracts crowded at the distal end and more widely
separated in the lower portion.
Williamsonia Bucklandi (Unger).
In 1837 Buckland[1251] gave an account of a ‘unique and beautiful fossil
fruit’ from Inferior Oolite beds at Charmouth in Dorsetshire and stated that
the type-specimen was in the Oxford Museum. Professor Sollas kindly
searched for the specimen some years ago but without success. Buckland
considered that the fruit was related to the Pandanaceae and described it as
follows: ‘The size of this fruit is that of a large orange, its surface is
occupied by a stellated covering or epicarpium, composed of hexagonal
tubercles, forming the summits of cells, which occupy the entire
circumference of the fruit. Within each cell is contained a single seed,
resembling a small grain of rice more or less compressed, and usually
hexagonal. When the epicarpium is removed, the points of the seeds are
seen, thickly studded over the surface of the fruit. The bases of the cells are
separated from the receptacle by a congeries of foot-stalks formed of a
dense mass of fibres, resembling the fibres beneath the base of the seeds of
the modern Pandanus.’ At the suggestion of Robert Brown he called the
‘fruit’ Podocarya, the specific name Bucklandi being afterwards given by
Unger[1252]. Brongniart[1253] called attention to the resemblance of Buckland’s
specimen to Williamsonia, and that name has been adopted by Saporta[1254],
Nathorst, and other authors[1255]. Sowerby’s drawings illustrating the original
description, one of which is reproduced in fig. 560, show that this unusually
fine specimen is an ovulate Bennettitean strobilus very similar in its thick
Page 495
conical receptacle to some of Wieland’s species of Cycadeoidea, e.g. C.
dacotensis (fig. 528): the armour of scales and megasporophylls agrees
exactly with that of some species of Williamsonia from Yorkshire and with
the flowers of Cycadeoidea. Though included in the genus Williamsonia it
would not be out of place in Cycadeoidea.
Fig. 560. Williamsonia Bucklandi. (After Buckland; ⅚ nat. size.)
Williamsonia scotica Seward.
The type-specimen was found by Hugh Miller near Cromarty (N.E.
Scotland) and figured as a cone of peculiar form[1256]; it was obtained from a
limestone nodule probably derived from Upper Jurassic rocks. The fossil is
11 cm. long and has a maximum breadth of 6 cm. (fig. 561): numerous
linear bracts cover the surface and in the lower portion many of them are
broken. A noteworthy feature is the absence of any clean-cut base, a fact
pointing to fracture rather than a natural abscission of the fertile axis. The
following description may serve to give a general idea of the salient
characters. Flowering shoot ovoid, covered with linear bracts some of
which are prolonged above the conical apex as slender tapered organs and
two of them bear a few short lateral appendages (fig. 561, l), probably
reduced leaflets, near their distal ends. The cylindrical axis, completely
dacotensis (fig. 528): the armour of scales and megasporophylls agrees
exactly with that of some species of Williamsonia from Yorkshire and with
the flowers of Cycadeoidea. Though included in the genus Williamsonia it
would not be out of place in Cycadeoidea.
Fig. 560. Williamsonia Bucklandi. (After Buckland; ⅚ nat. size.)
Williamsonia scotica Seward.
The type-specimen was found by Hugh Miller near Cromarty (N.E.
Scotland) and figured as a cone of peculiar form[1256]; it was obtained from a
limestone nodule probably derived from Upper Jurassic rocks. The fossil is
11 cm. long and has a maximum breadth of 6 cm. (fig. 561): numerous
linear bracts cover the surface and in the lower portion many of them are
broken. A noteworthy feature is the absence of any clean-cut base, a fact
pointing to fracture rather than a natural abscission of the fertile axis. The
following description may serve to give a general idea of the salient
characters. Flowering shoot ovoid, covered with linear bracts some of
which are prolonged above the conical apex as slender tapered organs and
two of them bear a few short lateral appendages (fig. 561, l), probably
reduced leaflets, near their distal ends. The cylindrical axis, completely
Page 496
hidden by bracts, 1·5 cm. in its widest part, bears in the lower or sterile
region bracts and long hairs and in the upper part interseminal scales and
immature megasporophylls which together form a narrow band (fig. 562, S)
2 mm. broad extending over the incompletely preserved and conical apex,
as in some of the American examples of Cycadeoidea. The strobilus was
probably borne at the apex of a lateral branch given off from a stem covered
with persistent petiole-bases: there is no evidence that this was the case, but
the appearance of the ovoid cone suggests comparison with those of
Williamsonia gigas which were terminal on fairly long branches and not
partially hidden among the bases of fronds as in Cycadeoidea. It is,
however, possible that the cone of Williamsonia scotica is a lateral
structure: this suggestion is based on the occurrence of a small branch or
bud, which may be the apex of the whole fertile shoot, given off from the
cone-axis but only revealed in transverse sections. The interseminal scales,
2 mm. long and 0·23 mm. broad at the truncate distal end (fig. 563), are
polygonal in section and arranged as rosettes of 5–6 around each
megasporophyll (fig. 564, a section tangential to the peripheral layer of
scales and sporophylls). The megasporophylls, equal in length to the scales,
consist of a cylindrical axis bearing a terminal megasporangium, an
undifferentiated nucellus, enclosed in a single integument prolonged as a
micropylar tube above the conical end of the nucellus (fig. 563, B, C, a).
Fig. 562 represents a transverse section through the cone showing the
cylindrical axis with its compact covering layer (fig. 563, A, s) of sterile
and fertile appendages, and beyond this sections of the enveloping bracts
embedded in a dense felt of long hairs. The tissue of the axis, though very
imperfectly preserved, shows occasional groups of secretory sacs and a few
patches of scalariform tracheids: there is evidence of the occurrence of
peripheral conducting tissue in the lower portion of the axis such as occurs
in the peduncles of American species of Cycadeoidea described by
Wieland. The bracts nearer the axis are more shrivelled than those farther
away, the result of the feebler development of hypodermal stereome in the
more internal bracts. Sunken stomata occur on the lower surface of some of
the bracts: several collateral bundles are present in each and large secretory
ducts are abundant. The numerous hairs on the bracts and the sterile region
of the cone are outgrowths of epidermal cells; most of them consist of a
short basal cell and a very long thick-walled tubular hair reaching a length
of several centimetres. In some cases the basal cell bears a group of short
region bracts and long hairs and in the upper part interseminal scales and
immature megasporophylls which together form a narrow band (fig. 562, S)
2 mm. broad extending over the incompletely preserved and conical apex,
as in some of the American examples of Cycadeoidea. The strobilus was
probably borne at the apex of a lateral branch given off from a stem covered
with persistent petiole-bases: there is no evidence that this was the case, but
the appearance of the ovoid cone suggests comparison with those of
Williamsonia gigas which were terminal on fairly long branches and not
partially hidden among the bases of fronds as in Cycadeoidea. It is,
however, possible that the cone of Williamsonia scotica is a lateral
structure: this suggestion is based on the occurrence of a small branch or
bud, which may be the apex of the whole fertile shoot, given off from the
cone-axis but only revealed in transverse sections. The interseminal scales,
2 mm. long and 0·23 mm. broad at the truncate distal end (fig. 563), are
polygonal in section and arranged as rosettes of 5–6 around each
megasporophyll (fig. 564, a section tangential to the peripheral layer of
scales and sporophylls). The megasporophylls, equal in length to the scales,
consist of a cylindrical axis bearing a terminal megasporangium, an
undifferentiated nucellus, enclosed in a single integument prolonged as a
micropylar tube above the conical end of the nucellus (fig. 563, B, C, a).
Fig. 562 represents a transverse section through the cone showing the
cylindrical axis with its compact covering layer (fig. 563, A, s) of sterile
and fertile appendages, and beyond this sections of the enveloping bracts
embedded in a dense felt of long hairs. The tissue of the axis, though very
imperfectly preserved, shows occasional groups of secretory sacs and a few
patches of scalariform tracheids: there is evidence of the occurrence of
peripheral conducting tissue in the lower portion of the axis such as occurs
in the peduncles of American species of Cycadeoidea described by
Wieland. The bracts nearer the axis are more shrivelled than those farther
away, the result of the feebler development of hypodermal stereome in the
more internal bracts. Sunken stomata occur on the lower surface of some of
the bracts: several collateral bundles are present in each and large secretory
ducts are abundant. The numerous hairs on the bracts and the sterile region
of the cone are outgrowths of epidermal cells; most of them consist of a
short basal cell and a very long thick-walled tubular hair reaching a length
of several centimetres. In some cases the basal cell bears a group of short
Page 497
cells each of which is the starting-point of a long hair: this is worthy of
notice from the point of view of comparison with the ramenta of other
Bennettitalean flowers. The short proximal cell of a hair is surrounded by a
cuticular ring like a rounded base-moulding where it rests on the epidermis:
this has been aptly compared to the dark rings that form a striking feature of
the cuticular membrane of Ptilophyllum leaflets[1257].
Fig. 561. Williamsonia scotica. Strobilus in surface-view; l, bract with
short lateral appendages. (Royal Scottish Museum, Edinburgh; ¾ nat.
size.)
notice from the point of view of comparison with the ramenta of other
Bennettitalean flowers. The short proximal cell of a hair is surrounded by a
cuticular ring like a rounded base-moulding where it rests on the epidermis:
this has been aptly compared to the dark rings that form a striking feature of
the cuticular membrane of Ptilophyllum leaflets[1257].
Fig. 561. Williamsonia scotica. Strobilus in surface-view; l, bract with
short lateral appendages. (Royal Scottish Museum, Edinburgh; ¾ nat.
size.)
Page 498
Fig. 562. Williamsonia scotica. Transverse section; S, scales and
megasporophylls; a, bract showing detached superficial tissue on the
inner side. (ca. × 2.)
megasporophylls; a, bract showing detached superficial tissue on the
inner side. (ca. × 2.)
Page 499
Fig. 563. Williamsonia scotica. Megasporophylls and interseminal scales
in longitudinal section. A, part of the axis showing the attachment,
s, of a scale and megasporophyll. B, apex of micropylar tube
showing funnel-shaped cavity and papillose epidermal cells on the
in longitudinal section. A, part of the axis showing the attachment,
s, of a scale and megasporophyll. B, apex of micropylar tube
showing funnel-shaped cavity and papillose epidermal cells on the
Page 500
integument and on the adjacent scale; a, apex of nucellus. C, upper
part of a scale and megasporophyll; a, apex of nucellus. (A, ca. ×
20; B, C, × 100.)
Fig. 564. Williamsonia scotica. Transverse section near the distal end of
a micropylar tube and the surrounding polygonal interseminal scales.
(ca. × 100.)
In the examination of the type-specimen the first section cut was
transverse to the axis (fig. 562), and this happened to traverse the lowest
part of the fertile region of the receptacle, as was shown by the fact that in
the next lower section the axis bore only bracts and hairs. It is clear that the
sterile portion of the receptacle passed abruptly upwards into the fertile
region, and it is extremely unlikely that any microsporophylls were borne at
the base of that portion of the cone-axis which produced the scales and
megasporophylls. The cone was, in all probability, unisexual. On the
analogy of the cones shown in figs. 513, 514, one would expect to find
between the sterile and fertile regions either a verticil of microsporophylls
part of a scale and megasporophyll; a, apex of nucellus. (A, ca. ×
20; B, C, × 100.)
Fig. 564. Williamsonia scotica. Transverse section near the distal end of
a micropylar tube and the surrounding polygonal interseminal scales.
(ca. × 100.)
In the examination of the type-specimen the first section cut was
transverse to the axis (fig. 562), and this happened to traverse the lowest
part of the fertile region of the receptacle, as was shown by the fact that in
the next lower section the axis bore only bracts and hairs. It is clear that the
sterile portion of the receptacle passed abruptly upwards into the fertile
region, and it is extremely unlikely that any microsporophylls were borne at
the base of that portion of the cone-axis which produced the scales and
megasporophylls. The cone was, in all probability, unisexual. On the
analogy of the cones shown in figs. 513, 514, one would expect to find
between the sterile and fertile regions either a verticil of microsporophylls
Page 501
or the remains of an annular disc from which the effete sporophylls had
been detached. There is no trace of any such disc, and the fact of the
immaturity of the megasporophylls renders it unlikely that were the cone
bisexual the microsporophylls would have been detached. As previous
records show, there is nothing improbable in the occurrence of a unisexual
Bennettitean flower. These remarks are made in view of an opinion
expressed by Dr Wieland that the bracts with lateral appendages (fig. 561,
l), to which allusion has been made, are microsporophylls and that if the
cone had been sliced longitudinally the presence of a microsporophyll-disc
would have been discovered. The latter possibility has already been
considered, and as regards the former there is nothing in the structure of the
small lateral appendages of the longest bracts to indicate that they were
connected with spore-production. It is not unlikely that the bracts with
small outgrowths (fig. 561, l) correspond to the more leaf-like bracts of
Wielandiella and Williamsoniella. The two sets of organs spoken of as
interseminal scales and megasporophylls are probably homologous, foliar,
structures; in the one case leaves transformed into cylindrical organs
bearing terminal integumented and undifferentiated megasporangia and, in
the other, sterile or sterilised sporophylls. The polygonal truncate distal end
of an interseminal scale is flat or slightly concave and covered by a thick
epidermis, and on the sides of the scale many of the surface-cells are
strongly papillose (figs. 563, 564). The rest of the interseminal scale
consists mainly of elongated cells, which in the lower portion of the axis of
the scale assume a tubular form, presumably immature conducting
elements: in one scale only was any tracheal tissue found and that was
represented by 2–3 scalariform tracheids. The scales appear to arise from
the axis like the bracts as superficial outgrowths, and probably in a later
stage of development the centre of each scale would be occupied by a
vascular strand. The megasporophylls bear a close resemblance to the
scales, but in transverse section they appear as smaller and circular organs
each the centre of a group of polygonal interseminal scales precisely as in
other Bennettitean flowers (fig. 564; cf. fig. 515). The proximal part of a
megasporophyll consists of a column of parenchyma (fig. 563, A, s)
extending through half of the length; from this column is detached a narrow
cylinder of small crushed cells which most likely represents the remains of
tissue that originally occupied the space surrounding the axial column. At a
higher level the axial column becomes broader and its short cells more
been detached. There is no trace of any such disc, and the fact of the
immaturity of the megasporophylls renders it unlikely that were the cone
bisexual the microsporophylls would have been detached. As previous
records show, there is nothing improbable in the occurrence of a unisexual
Bennettitean flower. These remarks are made in view of an opinion
expressed by Dr Wieland that the bracts with lateral appendages (fig. 561,
l), to which allusion has been made, are microsporophylls and that if the
cone had been sliced longitudinally the presence of a microsporophyll-disc
would have been discovered. The latter possibility has already been
considered, and as regards the former there is nothing in the structure of the
small lateral appendages of the longest bracts to indicate that they were
connected with spore-production. It is not unlikely that the bracts with
small outgrowths (fig. 561, l) correspond to the more leaf-like bracts of
Wielandiella and Williamsoniella. The two sets of organs spoken of as
interseminal scales and megasporophylls are probably homologous, foliar,
structures; in the one case leaves transformed into cylindrical organs
bearing terminal integumented and undifferentiated megasporangia and, in
the other, sterile or sterilised sporophylls. The polygonal truncate distal end
of an interseminal scale is flat or slightly concave and covered by a thick
epidermis, and on the sides of the scale many of the surface-cells are
strongly papillose (figs. 563, 564). The rest of the interseminal scale
consists mainly of elongated cells, which in the lower portion of the axis of
the scale assume a tubular form, presumably immature conducting
elements: in one scale only was any tracheal tissue found and that was
represented by 2–3 scalariform tracheids. The scales appear to arise from
the axis like the bracts as superficial outgrowths, and probably in a later
stage of development the centre of each scale would be occupied by a
vascular strand. The megasporophylls bear a close resemblance to the
scales, but in transverse section they appear as smaller and circular organs
each the centre of a group of polygonal interseminal scales precisely as in
other Bennettitean flowers (fig. 564; cf. fig. 515). The proximal part of a
megasporophyll consists of a column of parenchyma (fig. 563, A, s)
extending through half of the length; from this column is detached a narrow
cylinder of small crushed cells which most likely represents the remains of
tissue that originally occupied the space surrounding the axial column. At a
higher level the axial column becomes broader and its short cells more
Page 502
elongated and slightly divergent towards the sloping sides of the conical
nucellus. The loose cylinder of tissue is attached to the nucellar cone and
prolonged beyond its apex as a broad integument enclosing a very small
micropyle (fig. 563, C). The apex of the integument has the form of a
shallow funnel: its epidermal cells are papillose (fig. 563, B, C) and the
presence of short transversely elongated cells is a characteristic feature of
the tissue lining the micropylar canal. The bracts agree generally with those
of Cycadeoidea Gibsoniana, Cycadeoidea Morierei, and the American
species. The ground tissue is composed of sclerenchyma comparable with
the scalariform elements in the bracts of Cycadeoidea Gibsoniana (cf. fig.
520). It is in the possession of long hairs like those on the leaves of Dioon
and other recent Cycads that Williamsonia scotica differs from previously
described flowers in all of which the fern-like ramental scales are a
conspicuous feature. It is interesting to find that similar hairs are substituted
for scales in some Indian stems described by Miss Bancroft[1258]. Lignier[1259]
mentions the occurrence of long unicellular hairs on Cycadeoidea
micromyela (p. 415), a Jurassic French species, but the ramenta are in part
multicellular lamellae and the presence of transitional forms suggests a
possible derivation of hairs from scales both in fossil species and in recent
Cycads. The megasporophylls and interseminal scales are much shorter than
in Cycadeoidea Gibsoniana and other species in which the axis of the cone
forms a depressed receptacle (cf. fig. 521, A, C), but they correspond
closely with those of several American species. In Cycadeoidea Gibsoniana
and C. Morierei the distal ends of the interseminal scales are much broader
and their diameter greatly exceeds that of the micropylar tubes, 2·8 mm. as
compared with 0·25 mm., whereas in Williamsonia scotica the scales are
0·23 mm. broad and the micropylar tubes 0·15 mm. The mummified
micropylar tubes of W. pecten bear a striking resemblance in form and in
the papillose epidermal cells to those of the Scotch species.
There are two additional points suggested by the structure of the fertile
region, namely the possibility that the megasporophylls are arrested rather
than immature organs and, secondly, the method of pollination. In regard to
the first there would seem to be no adequate reason for doubting the
correctness of the view that the sporophylls are potentially perfect ovules
which were petrified at a comparatively early stage in development. The
dense woolly covering investing the surface of the scales and
megasporophylls recalls an inflorescence of Aesculus hippocastanum in its
nucellus. The loose cylinder of tissue is attached to the nucellar cone and
prolonged beyond its apex as a broad integument enclosing a very small
micropyle (fig. 563, C). The apex of the integument has the form of a
shallow funnel: its epidermal cells are papillose (fig. 563, B, C) and the
presence of short transversely elongated cells is a characteristic feature of
the tissue lining the micropylar canal. The bracts agree generally with those
of Cycadeoidea Gibsoniana, Cycadeoidea Morierei, and the American
species. The ground tissue is composed of sclerenchyma comparable with
the scalariform elements in the bracts of Cycadeoidea Gibsoniana (cf. fig.
520). It is in the possession of long hairs like those on the leaves of Dioon
and other recent Cycads that Williamsonia scotica differs from previously
described flowers in all of which the fern-like ramental scales are a
conspicuous feature. It is interesting to find that similar hairs are substituted
for scales in some Indian stems described by Miss Bancroft[1258]. Lignier[1259]
mentions the occurrence of long unicellular hairs on Cycadeoidea
micromyela (p. 415), a Jurassic French species, but the ramenta are in part
multicellular lamellae and the presence of transitional forms suggests a
possible derivation of hairs from scales both in fossil species and in recent
Cycads. The megasporophylls and interseminal scales are much shorter than
in Cycadeoidea Gibsoniana and other species in which the axis of the cone
forms a depressed receptacle (cf. fig. 521, A, C), but they correspond
closely with those of several American species. In Cycadeoidea Gibsoniana
and C. Morierei the distal ends of the interseminal scales are much broader
and their diameter greatly exceeds that of the micropylar tubes, 2·8 mm. as
compared with 0·25 mm., whereas in Williamsonia scotica the scales are
0·23 mm. broad and the micropylar tubes 0·15 mm. The mummified
micropylar tubes of W. pecten bear a striking resemblance in form and in
the papillose epidermal cells to those of the Scotch species.
There are two additional points suggested by the structure of the fertile
region, namely the possibility that the megasporophylls are arrested rather
than immature organs and, secondly, the method of pollination. In regard to
the first there would seem to be no adequate reason for doubting the
correctness of the view that the sporophylls are potentially perfect ovules
which were petrified at a comparatively early stage in development. The
dense woolly covering investing the surface of the scales and
megasporophylls recalls an inflorescence of Aesculus hippocastanum in its
Page 503
winter-fur and hardly suggests a collection of ovules accessible to
microspores. In all probability at a later stage the protecting bracts with
their felt of hairs would bend outwards leaving exposed the receptive
micropyles.
Microsporophylls.
In view of the association of microsporophylls and ovulate strobili in the
flowers of Cycadeoidea described by Wieland, most of which are bisexual,
it is reasonable to expect a similar association in the flowers of
Williamsonia which agree closely in the essential features of both micro-
and mega-sporophylls with those of Cycadeoidea. It is, therefore, surprising
that in no single case have the microsporophylls attributed to Williamsonia
been found in actual connexion with a receptacle bearing interseminal
scales and megasporophylls. The same statement holds good with regard to
the Williamsonias discovered in Mexico. Nathorst believes that the
microsporophylls on which he has founded several species are unisexual
flowers with the possible exception of W. pyramidalis[1260]. This species,
found by Dr Halle at Cloughton Wyke, is represented by a small ovulate
strobilus characterised by a conical receptacle with a blunt mucronate apex:
with it is associated a microsporophyll bearing synangia. The orientation of
the two specimens is such as to suggest an original connexion. As Nathorst
says, there is, however, no proof that the two belong to one flower.
Wieland[1261], though believing that the existence of bisporangiate
Williamsonia flowers is ‘reasonably certain,’ agrees with Nathorst’s
conclusion as to the unisexual character of W. spectabilis and W. pecten. On
the other hand, he regards the microsporophyll-verticil which was first
described by Williamson as a carpellary disc, then named by Nathorst[1262]
W. bituberculata and afterwards identified as a microsporophyll-disc closely
allied to W. whitbiensis, as the staminate part of W. gigas. This view is, in
my opinion, impossible to reconcile with the nature of the specimen. If, as
Wieland suggests, it is the staminal collar split off from the base of a large
ovulate cone like that of Williamsonia gigas, one would expect to find a
central space in the middle of the cupular base large enough to embrace the
receptacle. Neither in this specimen nor in several other forms of
microsporophyll-verticils is there such a central space. It is clear that the
discs described as W. spectabilis, W. whitbiensis, and other species were not
microspores. In all probability at a later stage the protecting bracts with
their felt of hairs would bend outwards leaving exposed the receptive
micropyles.
Microsporophylls.
In view of the association of microsporophylls and ovulate strobili in the
flowers of Cycadeoidea described by Wieland, most of which are bisexual,
it is reasonable to expect a similar association in the flowers of
Williamsonia which agree closely in the essential features of both micro-
and mega-sporophylls with those of Cycadeoidea. It is, therefore, surprising
that in no single case have the microsporophylls attributed to Williamsonia
been found in actual connexion with a receptacle bearing interseminal
scales and megasporophylls. The same statement holds good with regard to
the Williamsonias discovered in Mexico. Nathorst believes that the
microsporophylls on which he has founded several species are unisexual
flowers with the possible exception of W. pyramidalis[1260]. This species,
found by Dr Halle at Cloughton Wyke, is represented by a small ovulate
strobilus characterised by a conical receptacle with a blunt mucronate apex:
with it is associated a microsporophyll bearing synangia. The orientation of
the two specimens is such as to suggest an original connexion. As Nathorst
says, there is, however, no proof that the two belong to one flower.
Wieland[1261], though believing that the existence of bisporangiate
Williamsonia flowers is ‘reasonably certain,’ agrees with Nathorst’s
conclusion as to the unisexual character of W. spectabilis and W. pecten. On
the other hand, he regards the microsporophyll-verticil which was first
described by Williamson as a carpellary disc, then named by Nathorst[1262]
W. bituberculata and afterwards identified as a microsporophyll-disc closely
allied to W. whitbiensis, as the staminate part of W. gigas. This view is, in
my opinion, impossible to reconcile with the nature of the specimen. If, as
Wieland suggests, it is the staminal collar split off from the base of a large
ovulate cone like that of Williamsonia gigas, one would expect to find a
central space in the middle of the cupular base large enough to embrace the
receptacle. Neither in this specimen nor in several other forms of
microsporophyll-verticils is there such a central space. It is clear that the
discs described as W. spectabilis, W. whitbiensis, and other species were not
Page 504
borne as concrescent collars on a stout axis as are the corresponding organs
in Cycadeoidea. The Indian specimen reproduced in fig. 557 and the very
closely allied type W. setosa are incomplete at the centre and may possibly
have been borne at the base of an ovulate bisporangiate strobilus, but there
is no definite evidence that this was the case. Moreover, in W. spectabilis
the lower part of the cup (fig. 551) easily splits away from the rest of the
staminate disc, and this may explain the central space in the specimen
shown in fig. 549, A. If W. spectabilis, to take one example, is a complete
flower there are certain difficulties which are not easily explained: as
Nathorst has shown, in this type there is a short stalk, but in W. whitbiensis
the base of the funnel has no stalk and there is no interruption of the stout
lamina at the centre or any indication of a scar. Nathorst compares the
funnel-like region of W. whitbiensis to a kind of cupule which became
detached after flowering[1263]. But a cupule is supported on an axis and,
though no scar is apparent on some of the more complete specimens, it is
obvious that the verticil must have been supplied with vascular tissue from
some axial organ. This brings us to the consideration of a morphological
point which cannot be definitely answered. Nathorst has previously raised
the question—is it possible that the microsporophylls were attached to the
upper part of an ovulate strobilus; were the flowers bisexual and epigynous?
He believes the answer to be in the negative. Reference has already been
made to the probable occurrence at the apex of the receptacle of
Williamsonia gigas of a funnel-like organ of the type described by
Williamson as ‘carpellary disc[1264],’ a term under which Nathorst[1265]
believes that Williamson included two different things,—staminate discs
borne on separate, unisexual, flowers, and sterile organs called by
Lignier[1266] the infundibuliform apparatus. The latter, it is believed, were
attached to the apex of an ovulate strobilus as shown in fig. 548,
comparable in position with the leaves at the summit of an inflorescence of
Ananas. A comparison of the fossils regarded as infundibuliform
appendages with some of the microsporophyll-verticils shows that they are
identical in form, the only difference being that on the former there are no
synangia. This fact can hardly be regarded as negative evidence fatal to the
morphological identity of these sterile and fertile organs. The available
evidence, though far from complete, is favourable to the view that in some
Williamsonia flowers, e.g. W. gigas, the microsporophylls were produced at
the apex of the axis in the position shown in fig. 548. To cite a rough
in Cycadeoidea. The Indian specimen reproduced in fig. 557 and the very
closely allied type W. setosa are incomplete at the centre and may possibly
have been borne at the base of an ovulate bisporangiate strobilus, but there
is no definite evidence that this was the case. Moreover, in W. spectabilis
the lower part of the cup (fig. 551) easily splits away from the rest of the
staminate disc, and this may explain the central space in the specimen
shown in fig. 549, A. If W. spectabilis, to take one example, is a complete
flower there are certain difficulties which are not easily explained: as
Nathorst has shown, in this type there is a short stalk, but in W. whitbiensis
the base of the funnel has no stalk and there is no interruption of the stout
lamina at the centre or any indication of a scar. Nathorst compares the
funnel-like region of W. whitbiensis to a kind of cupule which became
detached after flowering[1263]. But a cupule is supported on an axis and,
though no scar is apparent on some of the more complete specimens, it is
obvious that the verticil must have been supplied with vascular tissue from
some axial organ. This brings us to the consideration of a morphological
point which cannot be definitely answered. Nathorst has previously raised
the question—is it possible that the microsporophylls were attached to the
upper part of an ovulate strobilus; were the flowers bisexual and epigynous?
He believes the answer to be in the negative. Reference has already been
made to the probable occurrence at the apex of the receptacle of
Williamsonia gigas of a funnel-like organ of the type described by
Williamson as ‘carpellary disc[1264],’ a term under which Nathorst[1265]
believes that Williamson included two different things,—staminate discs
borne on separate, unisexual, flowers, and sterile organs called by
Lignier[1266] the infundibuliform apparatus. The latter, it is believed, were
attached to the apex of an ovulate strobilus as shown in fig. 548,
comparable in position with the leaves at the summit of an inflorescence of
Ananas. A comparison of the fossils regarded as infundibuliform
appendages with some of the microsporophyll-verticils shows that they are
identical in form, the only difference being that on the former there are no
synangia. This fact can hardly be regarded as negative evidence fatal to the
morphological identity of these sterile and fertile organs. The available
evidence, though far from complete, is favourable to the view that in some
Williamsonia flowers, e.g. W. gigas, the microsporophylls were produced at
the apex of the axis in the position shown in fig. 548. To cite a rough
Page 505
analogy,—in Cycadeoidea the flower was hypogynous as in Erica; in
Williamsonia epigynous as in Vaccinium. This view does not exclude the
possibility of the existence of unisexual flowers in some species, but the
evidence in favour of a separation of the sexes is by no means decisive.
Another difficulty is the absence of protective bracts in the case of the
microsporophylls, a striking contrast to the bract-enclosed ovulate strobili
of Williamsonia or to the bract-covered flowers of Cycadeoidea. Were the
microsporophylls borne on a separate axis general considerations would
lead us to expect the association of bracts with the essential organs. The fact
that no such association has been recorded is a fact favourable to the view
that the flowers were bisporangiate.
Fig. 565. A, Williamsonia spectabilis, microsporophyll; B, W. whitbiensis,
section of sporophyll; C, W. mexicana. (A, B, after Nathorst; C, after
Wieland.)
The student is warned that the opinion expressed with regard to the
position of the microsporophylls is contrary to that which is held by several
palaeobotanists[1267].
Williamsonia epigynous as in Vaccinium. This view does not exclude the
possibility of the existence of unisexual flowers in some species, but the
evidence in favour of a separation of the sexes is by no means decisive.
Another difficulty is the absence of protective bracts in the case of the
microsporophylls, a striking contrast to the bract-enclosed ovulate strobili
of Williamsonia or to the bract-covered flowers of Cycadeoidea. Were the
microsporophylls borne on a separate axis general considerations would
lead us to expect the association of bracts with the essential organs. The fact
that no such association has been recorded is a fact favourable to the view
that the flowers were bisporangiate.
Fig. 565. A, Williamsonia spectabilis, microsporophyll; B, W. whitbiensis,
section of sporophyll; C, W. mexicana. (A, B, after Nathorst; C, after
Wieland.)
The student is warned that the opinion expressed with regard to the
position of the microsporophylls is contrary to that which is held by several
palaeobotanists[1267].
Page 506
Williamsonia mexicana Wieland.
This species is one of the numerous types discovered by Wieland in
Mexico[1268]. It is distinguished by the deep campanulate concrescent portion
of the whorl of microsporophylls and by the ten short free lobes which bear
two rows of lateral synangia (fig. 565, C). Among the British forms
Williamsonia whitbiensis would appear to be the most closely allied type.
W. mexicana occurs in association with Otozamites fronds, as is the case
with an Italian specimen figured by Zigno[1269], but in the Mexican species
there is no conclusive evidence of organic connexion.
Other species of Williamsonia.
Williamsonia Haydeni Seward.
A Jurassic species from Afghanistan[1270] founded on a single specimen of
a flattened broadly-oval flower similar to W. gigas but smaller and enclosed
by narrow linear bracts. An interesting feature is the occurrence of a funnel-
shaped depression at the apex showing radiating lines on its surface as in
the Williamsonia represented in fig. 546, A. In all probability these lines
denote the persistence of a collar of interseminal scales on the upper part of
the elongated conical receptacle. An examination of the carbonaceous
material revealed the presence of some short rods agreeing in size and
shape with the interseminal scales of other species.
Williamsonia Otozamitis (Zigno).
Zigno[1271] instituted the generic name Blastolepis for some specimens
from the Jurassic rocks of north Italy which he referred to three species, B.
falcata, B. acuminata, and B. Otozamitis. These are true Williamsonias
closely allied to W. gigas. An examination of the type-specimen of B.
Otozamitis in the Padua collection led me to the conclusion that Zigno was
correct in representing the ovulate strobilus, which shows an annular area
like that in specimens of W. gigas, as being in organic connexion with an
Otozamites frond. Wieland has recently discovered species of Williamsonia
in Mexico that he correlates with Otozamites leaves.
Williamsonia sp. Seward.
This species is one of the numerous types discovered by Wieland in
Mexico[1268]. It is distinguished by the deep campanulate concrescent portion
of the whorl of microsporophylls and by the ten short free lobes which bear
two rows of lateral synangia (fig. 565, C). Among the British forms
Williamsonia whitbiensis would appear to be the most closely allied type.
W. mexicana occurs in association with Otozamites fronds, as is the case
with an Italian specimen figured by Zigno[1269], but in the Mexican species
there is no conclusive evidence of organic connexion.
Other species of Williamsonia.
Williamsonia Haydeni Seward.
A Jurassic species from Afghanistan[1270] founded on a single specimen of
a flattened broadly-oval flower similar to W. gigas but smaller and enclosed
by narrow linear bracts. An interesting feature is the occurrence of a funnel-
shaped depression at the apex showing radiating lines on its surface as in
the Williamsonia represented in fig. 546, A. In all probability these lines
denote the persistence of a collar of interseminal scales on the upper part of
the elongated conical receptacle. An examination of the carbonaceous
material revealed the presence of some short rods agreeing in size and
shape with the interseminal scales of other species.
Williamsonia Otozamitis (Zigno).
Zigno[1271] instituted the generic name Blastolepis for some specimens
from the Jurassic rocks of north Italy which he referred to three species, B.
falcata, B. acuminata, and B. Otozamitis. These are true Williamsonias
closely allied to W. gigas. An examination of the type-specimen of B.
Otozamitis in the Padua collection led me to the conclusion that Zigno was
correct in representing the ovulate strobilus, which shows an annular area
like that in specimens of W. gigas, as being in organic connexion with an
Otozamites frond. Wieland has recently discovered species of Williamsonia
in Mexico that he correlates with Otozamites leaves.
Williamsonia sp. Seward.
Page 507
Though by no means satisfactory as a trustworthy record of the genus,
the specimens so designated from the Kimmeridgian of Scotland[1272] are
probably imperfect examples of the genus.
Williamsonia oregonensis Fontaine.
The type-specimen from Jurassic rocks in Oregon[1273] consists of a stout
axis bearing several contiguous linear bracts forming a more or less
spherical cluster 5 cm. broad. The form suggests a Williamsonia, but the
evidence is hardly decisive.
Williamsonia Forchammeri Nathorst.
A Bornholm species[1274] from Lower Jurassic strata represented by an
annular zone surrounding a central area, probably a portion of an ovulate
strobilus.
Williamsonia minima Saporta.
This Upper Jurassic species from Portugal[1275] consists of a number of
small bracts or leaves attached to a central axis and is of no value as
evidence of the occurrence of Williamsonia.
Williamsonia problematica (Newberry).
This species was first described from the Amboy clays as Palaeanthus
(Williamsonia) problematica[1276] and compared to a Composite
inflorescence with long ray-florets. More recently Hollick[1277] has referred
to this species specimens from the Cretaceous of Long Island and Martha’s
Vineyard, but none of them afford conclusive evidence of Williamsonian
affinity. Some of the examples, as suggested by Hollick, agree fairly closely
with Williamsonia cretacea Heer.
Williamsonia Smockii Newberry.
The curious urn-like bodies from the Amboy clays[1278] on which this
species is based are not unlike the capsules of a Papaver but bear no real
resemblance to a Williamsonia.
Williamsonia Riesii Hollick.
the specimens so designated from the Kimmeridgian of Scotland[1272] are
probably imperfect examples of the genus.
Williamsonia oregonensis Fontaine.
The type-specimen from Jurassic rocks in Oregon[1273] consists of a stout
axis bearing several contiguous linear bracts forming a more or less
spherical cluster 5 cm. broad. The form suggests a Williamsonia, but the
evidence is hardly decisive.
Williamsonia Forchammeri Nathorst.
A Bornholm species[1274] from Lower Jurassic strata represented by an
annular zone surrounding a central area, probably a portion of an ovulate
strobilus.
Williamsonia minima Saporta.
This Upper Jurassic species from Portugal[1275] consists of a number of
small bracts or leaves attached to a central axis and is of no value as
evidence of the occurrence of Williamsonia.
Williamsonia problematica (Newberry).
This species was first described from the Amboy clays as Palaeanthus
(Williamsonia) problematica[1276] and compared to a Composite
inflorescence with long ray-florets. More recently Hollick[1277] has referred
to this species specimens from the Cretaceous of Long Island and Martha’s
Vineyard, but none of them afford conclusive evidence of Williamsonian
affinity. Some of the examples, as suggested by Hollick, agree fairly closely
with Williamsonia cretacea Heer.
Williamsonia Smockii Newberry.
The curious urn-like bodies from the Amboy clays[1278] on which this
species is based are not unlike the capsules of a Papaver but bear no real
resemblance to a Williamsonia.
Williamsonia Riesii Hollick.
Page 508
A species from the Cretaceous rocks of Martha’s Vineyard[1279] referred to
Williamsonia on rather slender grounds and represented by imperfect
material.
Williamsonia (?) phoenicopsoides Ward.
This fossil from the Cretaceous of the Black Hills, Dakota[1280], is much
too imperfect to be accepted as a record of Williamsonia.
Williamsonia elongata Lesquereux.
This species, founded on part of a conical receptacle with some
appendages superficially resembling those of Williamsonia[1281], is too
incomplete to be determined with any confidence. The type-specimen is
from Cenomanian beds in Kansas.
Williamsonia virginiensis Fontaine.
This is undoubtedly a true member of the genus; it is characterised by
narrow ovate bracts bearing conspicuous hairs surrounding the base of a
receptacle which shows a portion of an annular zone of interseminal
scales[1282].
Williamsonia (?) gallinacea Ward.
This species from the Potomac beds[1283] is of no value as a record of
Williamsonia.
Williamsonia (?) Bibbinsi Ward.
The imperfectly preserved specimen from the Potomac series so named
by Ward[1284] is probably part of an Abietineous cone as stated by Berry[1285]
who includes Ward’s type with other specimens referred to Abietites
macrocarpus Font.
Williamsonia cretacea Heer.
Two specimens, figured by Heer[1286] from the Lower Cretaceous of
Greenland, on which this species is founded, consist of an axis covered with
small scale-leaves and at the broad apex bearing numerous narrow linear
Williamsonia on rather slender grounds and represented by imperfect
material.
Williamsonia (?) phoenicopsoides Ward.
This fossil from the Cretaceous of the Black Hills, Dakota[1280], is much
too imperfect to be accepted as a record of Williamsonia.
Williamsonia elongata Lesquereux.
This species, founded on part of a conical receptacle with some
appendages superficially resembling those of Williamsonia[1281], is too
incomplete to be determined with any confidence. The type-specimen is
from Cenomanian beds in Kansas.
Williamsonia virginiensis Fontaine.
This is undoubtedly a true member of the genus; it is characterised by
narrow ovate bracts bearing conspicuous hairs surrounding the base of a
receptacle which shows a portion of an annular zone of interseminal
scales[1282].
Williamsonia (?) gallinacea Ward.
This species from the Potomac beds[1283] is of no value as a record of
Williamsonia.
Williamsonia (?) Bibbinsi Ward.
The imperfectly preserved specimen from the Potomac series so named
by Ward[1284] is probably part of an Abietineous cone as stated by Berry[1285]
who includes Ward’s type with other specimens referred to Abietites
macrocarpus Font.
Williamsonia cretacea Heer.
Two specimens, figured by Heer[1286] from the Lower Cretaceous of
Greenland, on which this species is founded, consist of an axis covered with
small scale-leaves and at the broad apex bearing numerous narrow linear
Page 509
bracts forming a more or less spherical cluster 3·8 cm. in breadth. The
species resembles W. problematica (Newb.).
Williamsonia recentior Dawson.
The specimens from the Middle Cretaceous of Canada figured by
Dawson[1287] under this name are very imperfect and of no botanical value.
Fig. 566. Wielandiella angustifolia. (After Nathorst.)
WIELANDIELLA. Nathorst.
The specimens on which this genus is founded were originally described
by Nathorst from Höör in Scania as Williamsonia angustifolia[1288]: in a
second paper[1289] a restoration of the plant was published (fig. 566). The
examination of additional specimens from the Rhaetic of Bjuf and of
cuticular preparations led to the establishment of a new genus
Wielandia[1290] for which Wielandiella[1291] was afterwards substituted,
Wielandia having been previously employed for an existing plant.
Wielandiella agrees in the general morphology of its bisporangiate flowers
with Cycadeoidea, but differs widely from nearly all other members of the
Bennettitales in the repeatedly forked slender stem which is in marked
species resembles W. problematica (Newb.).
Williamsonia recentior Dawson.
The specimens from the Middle Cretaceous of Canada figured by
Dawson[1287] under this name are very imperfect and of no botanical value.
Fig. 566. Wielandiella angustifolia. (After Nathorst.)
WIELANDIELLA. Nathorst.
The specimens on which this genus is founded were originally described
by Nathorst from Höör in Scania as Williamsonia angustifolia[1288]: in a
second paper[1289] a restoration of the plant was published (fig. 566). The
examination of additional specimens from the Rhaetic of Bjuf and of
cuticular preparations led to the establishment of a new genus
Wielandia[1290] for which Wielandiella[1291] was afterwards substituted,
Wielandia having been previously employed for an existing plant.
Wielandiella agrees in the general morphology of its bisporangiate flowers
with Cycadeoidea, but differs widely from nearly all other members of the
Bennettitales in the repeatedly forked slender stem which is in marked
Page 510
contrast to the vegetative axis of any recent Cycad. Among recent Cycads
with terminal strobili an indication of a primitive dichasium is afforded by
the occurrence of an aborted bud in a stem of Dioon edule described by
South and Compton[1292]; but in the habit of the stem Wielandiella is far
removed from any recent Cycadean type. The microsporophylls are smaller
and simpler than in Williamsonia or Cycadeoidea and the foliage-leaves are
of the Anomozamites type (cf. fig. 615).
Fig. 567. Wielandiella angustifolia. Branched stem and receptacle.
(After Nathorst.)
Wielandiella angustifolia Nathorst.
In an account of this species in 1902 Nathorst described two types of
strobilus, male and female, but a re-investigation of the material led to a
modification of the earlier conclusions. The stem is slender, rarely
exceeding 1·5 cm. in breadth, repeatedly branched as a dichasial system
with a fertile shoot in the forks formed by the equal and widely divergent
branches. Nathorst’s restoration, as he points out, may exaggerate the
regularity of the branching, but an examination of the original specimens in
the Stockholm Museum convinced me that the habit represented in fig. 566
is substantially correct. The method of branching is similar to that in the
inflorescences of Gnetalean plants and recalls some Gleichenia fronds. The
with terminal strobili an indication of a primitive dichasium is afforded by
the occurrence of an aborted bud in a stem of Dioon edule described by
South and Compton[1292]; but in the habit of the stem Wielandiella is far
removed from any recent Cycadean type. The microsporophylls are smaller
and simpler than in Williamsonia or Cycadeoidea and the foliage-leaves are
of the Anomozamites type (cf. fig. 615).
Fig. 567. Wielandiella angustifolia. Branched stem and receptacle.
(After Nathorst.)
Wielandiella angustifolia Nathorst.
In an account of this species in 1902 Nathorst described two types of
strobilus, male and female, but a re-investigation of the material led to a
modification of the earlier conclusions. The stem is slender, rarely
exceeding 1·5 cm. in breadth, repeatedly branched as a dichasial system
with a fertile shoot in the forks formed by the equal and widely divergent
branches. Nathorst’s restoration, as he points out, may exaggerate the
regularity of the branching, but an examination of the original specimens in
the Stockholm Museum convinced me that the habit represented in fig. 566
is substantially correct. The method of branching is similar to that in the
inflorescences of Gnetalean plants and recalls some Gleichenia fronds. The
Page 511
surface of the thicker pieces of stem shows fine longitudinal striae, while
transverse striations like those on the axis of a Heterangium frond
characterise the more slender specimens. Closely set polygonal leaf-scars
cover the stem for a short distance below each bifurcation and the surface of
the short and relatively stout peduncles of the strobili (fig. 567). Though for
the most part confined to the region of false dichotomy, leaf-scars
occasionally occur on other parts of the stem. Small fronds, 7–8 cm. long,
agreeing closely with Anomozamites minor Brongn., occur in the same beds
at Bjuf, and the striking resemblance between their long linear and winged
petioles and the transversely striated bracts enclosing the strobili of
Wielandiella amply justifies Nathorst’s conclusion that Wielandiella bore
fronds of the Anomozamites form[1293]. Small scars marking the position of
bracts occur immediately below each strobilus and occasionally form
narrow zones between the larger foliage leaf-scars. The strobili are met with
in two forms representing two states of preservation and, probably, different
ages. In one form the strobilus consists of a small pyriform axis separated
from the peduncle by an annular swelling characterised by parallel
striations (fig. 567), the so-called palisade-ring. From this ring Nathorst
obtained many microspores scattered and in groups on the surface of short
sporophylls, 2·5–3 mm. in length. It is these sporophylls which form the
parallel striations; they occur as a circle of rather broad linear organs with
irregularly toothed distal ends and an epidermis of papillose cells. The oval
microspores, 32–42μ long, vary in size and, as Nathorst says, this may
indicate immaturity. The precise mode of occurrence of the spores has not
been ascertained, but they were probably produced in sporangia on the
surface of the small microsporophylls. These strobili have in all probability
lost the female organs which were borne on the pyriform axis, and the
inference is that the strobili were protogynous. Thomas[1294] compares the
ring at the base of the flower-axis from which spores were obtained by
Nathorst to the whorl of microsporophylls of Williamsoniella, but in
Wielandiella the sporophylls are greatly reduced and possibly functionless.
Wielandiella may be intermediate between the bisexual Williamsoniella and
the unisexual Williamsonia scotica. In the second form of strobilus the
pyriform axis is hidden and the specimens consist of a central ovate body,
approximately 3 cm. long, surrounded by several linear bracts (fig. 568, A).
The carbonised surface of the central region revealed on chemical treatment
a fairly regular pattern formed by the contiguous polygonal ends of
transverse striations like those on the axis of a Heterangium frond
characterise the more slender specimens. Closely set polygonal leaf-scars
cover the stem for a short distance below each bifurcation and the surface of
the short and relatively stout peduncles of the strobili (fig. 567). Though for
the most part confined to the region of false dichotomy, leaf-scars
occasionally occur on other parts of the stem. Small fronds, 7–8 cm. long,
agreeing closely with Anomozamites minor Brongn., occur in the same beds
at Bjuf, and the striking resemblance between their long linear and winged
petioles and the transversely striated bracts enclosing the strobili of
Wielandiella amply justifies Nathorst’s conclusion that Wielandiella bore
fronds of the Anomozamites form[1293]. Small scars marking the position of
bracts occur immediately below each strobilus and occasionally form
narrow zones between the larger foliage leaf-scars. The strobili are met with
in two forms representing two states of preservation and, probably, different
ages. In one form the strobilus consists of a small pyriform axis separated
from the peduncle by an annular swelling characterised by parallel
striations (fig. 567), the so-called palisade-ring. From this ring Nathorst
obtained many microspores scattered and in groups on the surface of short
sporophylls, 2·5–3 mm. in length. It is these sporophylls which form the
parallel striations; they occur as a circle of rather broad linear organs with
irregularly toothed distal ends and an epidermis of papillose cells. The oval
microspores, 32–42μ long, vary in size and, as Nathorst says, this may
indicate immaturity. The precise mode of occurrence of the spores has not
been ascertained, but they were probably produced in sporangia on the
surface of the small microsporophylls. These strobili have in all probability
lost the female organs which were borne on the pyriform axis, and the
inference is that the strobili were protogynous. Thomas[1294] compares the
ring at the base of the flower-axis from which spores were obtained by
Nathorst to the whorl of microsporophylls of Williamsoniella, but in
Wielandiella the sporophylls are greatly reduced and possibly functionless.
Wielandiella may be intermediate between the bisexual Williamsoniella and
the unisexual Williamsonia scotica. In the second form of strobilus the
pyriform axis is hidden and the specimens consist of a central ovate body,
approximately 3 cm. long, surrounded by several linear bracts (fig. 568, A).
The carbonised surface of the central region revealed on chemical treatment
a fairly regular pattern formed by the contiguous polygonal ends of
Page 512
interseminal scales arranged round smaller cylindrical micropylar tubes
which project beyond the level of the scales (fig. 568, B). This arrangement
agrees closely with that of the corresponding organs in Williamsonia and
Cycadeoidea (cf. figs. 515, 564). In Wielandiella the micropylar tubes are of
uniform diameter and the cells of the epidermis have smooth walls in
contrast to the micropylar tubes of Williamsonia (fig. 563). The strobilus in
this state, before the scales and ovules have become detached from the axis,
may be described as a small Williamsonia, but the habit of the stem is in
itself a sufficient reason for the use of a distinctive generic name[1295].
Fig. 568. Wielandiella angustifolia. A, conical receptacle with bracts. B,
surface-view of scales and micropylar tubes. (After Nathorst; A, ¾
nat. size.)
A second species, Wielandiella punctata, described by Nathorst[1296] from
Scania is founded on pieces of forked stems associated with fragments of a
palisade-ring formed of contiguous segments (microsporophylls) with
microspores 58μ in length. Fronds of Anomozamites minor occur in the
same beds.
Mr Hamshaw Thomas[1297] described some specimens from the Middle
Jurassic beds of Marske in Yorkshire which he suggested might be pieces of
a Wielandiella stem. Additional material was subsequently found and this
enabled Thomas to produce evidence in favour of connecting the branched
vegetative axis with bisporangiate strobili and the fronds of Taeniopteris
vittata. For the stems and flowers the new designation Williamsoniella has
which project beyond the level of the scales (fig. 568, B). This arrangement
agrees closely with that of the corresponding organs in Williamsonia and
Cycadeoidea (cf. figs. 515, 564). In Wielandiella the micropylar tubes are of
uniform diameter and the cells of the epidermis have smooth walls in
contrast to the micropylar tubes of Williamsonia (fig. 563). The strobilus in
this state, before the scales and ovules have become detached from the axis,
may be described as a small Williamsonia, but the habit of the stem is in
itself a sufficient reason for the use of a distinctive generic name[1295].
Fig. 568. Wielandiella angustifolia. A, conical receptacle with bracts. B,
surface-view of scales and micropylar tubes. (After Nathorst; A, ¾
nat. size.)
A second species, Wielandiella punctata, described by Nathorst[1296] from
Scania is founded on pieces of forked stems associated with fragments of a
palisade-ring formed of contiguous segments (microsporophylls) with
microspores 58μ in length. Fronds of Anomozamites minor occur in the
same beds.
Mr Hamshaw Thomas[1297] described some specimens from the Middle
Jurassic beds of Marske in Yorkshire which he suggested might be pieces of
a Wielandiella stem. Additional material was subsequently found and this
enabled Thomas to produce evidence in favour of connecting the branched
vegetative axis with bisporangiate strobili and the fronds of Taeniopteris
vittata. For the stems and flowers the new designation Williamsoniella has
Page 513
been proposed. Further research will no doubt show that the Wielandiella
type of stem was not exceptional in Rhaetic and Jurassic floras.
Nathorst[1298] suggests the possibility that some specimens from the
Solenhofen Slates described by Thiselton-Dyer[1299] as Condylites
squamatus may be allied to Wielandiella. The generic name Condylites was
suggested by the elbow-like branching of stems which bore imperfectly
preserved and apparently terminal cones; the surface of the branches is
covered with the scars of leaves. The resemblance to Wielandiella is,
however, slight and it would seem more probable that the Solenhofen
fossils are Coniferous, though, as Nathorst says, the supposed scale-like
‘leaves’ may be scars of Cycadean fronds.
Wieland[1300] records the occurrence in Mexico of stems similar to those
of Wielandiella associated with some Otozamites fronds.
WILLIAMSONIELLA. Thomas.
This genus was instituted for specimens discovered by Mr Hamshaw
Thomas[1301] in the Middle Estuarine series of the Middle Jurassic plant-bed
at Gristhorpe on the Yorkshire coast, and the genus is recorded also from
the Cleveland district in the same county. Williamsoniella occurs in those
parts of the Gristhorpe bed where fronds of Taeniopteris vittata are
abundant.
Williamsoniella coronata Thomas.
The type-species is represented by fertile shoots consisting of a central
axis bearing both megasporophylls and microsporophylls (figs. 569, 571,
A). Below its crown-like sterile apex the pyriform peduncle is covered with
small interseminal scales and ovules similar to those of Williamsonia: this
portion is 6 mm. in diameter and 1 cm. long. A whorl of separate cuneate
microsporophylls forms a hypogynous ring below the basal interseminal
scales: each sporophyll is attached by a narrow base (fig. 570) and bears 5–
6 reniform synangia containing microspores. The flower is thus bisexual: it
affords no conclusive evidence of the occurrence of any covering bracts like
those of most Bennettitalean flowers. In young specimens the
microsporophylls are closely packed round the axis (fig. 571, B). The
flower-stalks reach a length of 3·5 cm. and are 3 mm. in diameter. Fig. 571,
type of stem was not exceptional in Rhaetic and Jurassic floras.
Nathorst[1298] suggests the possibility that some specimens from the
Solenhofen Slates described by Thiselton-Dyer[1299] as Condylites
squamatus may be allied to Wielandiella. The generic name Condylites was
suggested by the elbow-like branching of stems which bore imperfectly
preserved and apparently terminal cones; the surface of the branches is
covered with the scars of leaves. The resemblance to Wielandiella is,
however, slight and it would seem more probable that the Solenhofen
fossils are Coniferous, though, as Nathorst says, the supposed scale-like
‘leaves’ may be scars of Cycadean fronds.
Wieland[1300] records the occurrence in Mexico of stems similar to those
of Wielandiella associated with some Otozamites fronds.
WILLIAMSONIELLA. Thomas.
This genus was instituted for specimens discovered by Mr Hamshaw
Thomas[1301] in the Middle Estuarine series of the Middle Jurassic plant-bed
at Gristhorpe on the Yorkshire coast, and the genus is recorded also from
the Cleveland district in the same county. Williamsoniella occurs in those
parts of the Gristhorpe bed where fronds of Taeniopteris vittata are
abundant.
Williamsoniella coronata Thomas.
The type-species is represented by fertile shoots consisting of a central
axis bearing both megasporophylls and microsporophylls (figs. 569, 571,
A). Below its crown-like sterile apex the pyriform peduncle is covered with
small interseminal scales and ovules similar to those of Williamsonia: this
portion is 6 mm. in diameter and 1 cm. long. A whorl of separate cuneate
microsporophylls forms a hypogynous ring below the basal interseminal
scales: each sporophyll is attached by a narrow base (fig. 570) and bears 5–
6 reniform synangia containing microspores. The flower is thus bisexual: it
affords no conclusive evidence of the occurrence of any covering bracts like
those of most Bennettitalean flowers. In young specimens the
microsporophylls are closely packed round the axis (fig. 571, B). The
flower-stalks reach a length of 3·5 cm. and are 3 mm. in diameter. Fig. 571,
Page 514
C, shows a receptacle from which the sporophylls have fallen: the
microsporophylls having been no doubt attached to the collar-like swelling
at the base. Towards the apex the axis becomes broader and at s a few
interseminal scales are left: above these is the apical disc (corona)
characterised by longitudinal ribs. An apical disc is reproduced in fig. 572;
it has the form of a royal crown 1–2 mm. high with 12–16 vertical ridges
separating flat surfaces formed by the pressure of microsporophyll apices in
the unexpanded flower. The corona is surmounted by a small conical
elevation which represents the apex of the fertile axis. An apical view of an
unexpanded flower is shown in fig. 571, B; the tips of 12 sporophylls are
closely pressed against the corona which probably consists in part at least of
fused interseminal scales. The microsporophylls were shed after the
dehiscence of the synangia. Each sporophyll is flattened on the sides and
thicker on the curved outer edge; the synangia, usually in two rows of three,
are borne on the sloping sides (figs. 569, 570). The surface of a
microsporophyll is covered with small rounded projections which produce a
characteristic appearance. The form of a microsporophyll in section is
shown in fig. 570: the synangia are similar in shape to those of
Cycadeoidea and Williamsonia (cf. figs. 531, 549, etc.) but there are no
external indications of septa like those seen in some other types. On
macerating some specimens it was found that the spores occur in about 20
groups. The circular or elliptical spores are 0·02 mm. in diameter. The walls
of the epidermal cells of the microsporophylls are straight: the stomata,
which show the features characteristic of the Bennettitales, agree closely
with those of Taenopteris vittata.
microsporophylls having been no doubt attached to the collar-like swelling
at the base. Towards the apex the axis becomes broader and at s a few
interseminal scales are left: above these is the apical disc (corona)
characterised by longitudinal ribs. An apical disc is reproduced in fig. 572;
it has the form of a royal crown 1–2 mm. high with 12–16 vertical ridges
separating flat surfaces formed by the pressure of microsporophyll apices in
the unexpanded flower. The corona is surmounted by a small conical
elevation which represents the apex of the fertile axis. An apical view of an
unexpanded flower is shown in fig. 571, B; the tips of 12 sporophylls are
closely pressed against the corona which probably consists in part at least of
fused interseminal scales. The microsporophylls were shed after the
dehiscence of the synangia. Each sporophyll is flattened on the sides and
thicker on the curved outer edge; the synangia, usually in two rows of three,
are borne on the sloping sides (figs. 569, 570). The surface of a
microsporophyll is covered with small rounded projections which produce a
characteristic appearance. The form of a microsporophyll in section is
shown in fig. 570: the synangia are similar in shape to those of
Cycadeoidea and Williamsonia (cf. figs. 531, 549, etc.) but there are no
external indications of septa like those seen in some other types. On
macerating some specimens it was found that the spores occur in about 20
groups. The circular or elliptical spores are 0·02 mm. in diameter. The walls
of the epidermal cells of the microsporophylls are straight: the stomata,
which show the features characteristic of the Bennettitales, agree closely
with those of Taenopteris vittata.
Page 515
Fig. 570. Williamsoniella coronata.
Diagrammatic sketch of a
microsporophyll in section and in
side-view. (After Thomas; × 3.)
Fig. 569. Williamsoniella coronata.
Vertical section of the flower
showing the pyriform axis with
small megasporophylls and
interseminal scales and the
microsporophylls with synangia.
(After Thomas; × 2.)
Diagrammatic sketch of a
microsporophyll in section and in
side-view. (After Thomas; × 3.)
Fig. 569. Williamsoniella coronata.
Vertical section of the flower
showing the pyriform axis with
small megasporophylls and
interseminal scales and the
microsporophylls with synangia.
(After Thomas; × 2.)
Page 516
Fig. 571. Williamsoniella coronata. A, flower showing two
microsporophylls and the central axis with megasporophylls. B,
microsporophylls and the central axis with megasporophylls. B,
Page 517
apical view of an unexpanded flower. C, flower-axis showing the
shallow grooves made by the infolded microsporophylls, which
have fallen, and a few megasporophylls, s. (After Thomas; A, × 1⅓;
B, C, × 3.)
The interseminal scales associated with the
ovules and covering the pyriform axis above the
microsporophylls are more or less flattened and
hexagonal and the micropylar tubes often
project far beyond the scales. Each micropyle-
tube is surrounded by 5–6 interseminal scales
(cf. fig. 564). The ovules differ from those of
Cycadeoidea Gibsoniana in the absence of a
distinct pedicel and agree with the
corresponding organs of Williamsonia
scotica [1302]
. In the absence of epidermal papillae Fig. 572. Williamsoniella
the micropylar tubes resemble those of coronata. Apical disc
Wielandiella angustifolia. As already stated, the with megasporophylls
flowers appear to be without protective bracts, and interseminal scales
but in the shale from which the specimens were at the base. (After
obtained a few bract-like organs were Thomas; × 3.)
discovered consisting of a lanceolate lamina 1·5 cm. long, and 2–3 mm.
broad near the base, and some showed a small oval lamina at the apex with
a midrib and dichotomously branched lateral veins. These bracts with the
terminal lamina are regarded by Thomas as almost certainly reduced leaves
of the Taeniopteris vittata type: they are represented in the restoration (fig.
573) as occurring at the base of the flower-peduncle. Stomata were found
on the bracts exactly like those on the microsporophylls, and this affords a
strong argument in support of the view that Williamsoniella belongs to the
plant which bore Taeniopteris fronds. There is a close parallelism between
the bracts accompanying Williamsoniella flowers and those described by
Nathorst in connexion with Wielandiella[1303]. It seems reasonable to regard
the bracts as serving the purpose of bud-scales.
shallow grooves made by the infolded microsporophylls, which
have fallen, and a few megasporophylls, s. (After Thomas; A, × 1⅓;
B, C, × 3.)
The interseminal scales associated with the
ovules and covering the pyriform axis above the
microsporophylls are more or less flattened and
hexagonal and the micropylar tubes often
project far beyond the scales. Each micropyle-
tube is surrounded by 5–6 interseminal scales
(cf. fig. 564). The ovules differ from those of
Cycadeoidea Gibsoniana in the absence of a
distinct pedicel and agree with the
corresponding organs of Williamsonia
scotica [1302]
. In the absence of epidermal papillae Fig. 572. Williamsoniella
the micropylar tubes resemble those of coronata. Apical disc
Wielandiella angustifolia. As already stated, the with megasporophylls
flowers appear to be without protective bracts, and interseminal scales
but in the shale from which the specimens were at the base. (After
obtained a few bract-like organs were Thomas; × 3.)
discovered consisting of a lanceolate lamina 1·5 cm. long, and 2–3 mm.
broad near the base, and some showed a small oval lamina at the apex with
a midrib and dichotomously branched lateral veins. These bracts with the
terminal lamina are regarded by Thomas as almost certainly reduced leaves
of the Taeniopteris vittata type: they are represented in the restoration (fig.
573) as occurring at the base of the flower-peduncle. Stomata were found
on the bracts exactly like those on the microsporophylls, and this affords a
strong argument in support of the view that Williamsoniella belongs to the
plant which bore Taeniopteris fronds. There is a close parallelism between
the bracts accompanying Williamsoniella flowers and those described by
Nathorst in connexion with Wielandiella[1303]. It seems reasonable to regard
the bracts as serving the purpose of bud-scales.
Page 518
Fig. 573. Williamsoniella coronata. Restoration of part of a plant: the
upper leaves are represented only by the petiole-bases. (After
Thomas; ca. ⅜ nat. size.)
An important point is the constant association with the flowers of
Taeniopteris vittata fronds, a species described in Vol. ii. and by most
palaeobotanists regarded as a Fern frond. Taeniopteris leaves occasionally
show a clean-cut base[1304] and in specimens described by Thomas there are
two small humps on the surface of the proximal end of the petiole which
represent vascular bundles. Humps of similar size occur on the leaf-scars of
stems which are believed to have borne both Taeniopteris leaves and
upper leaves are represented only by the petiole-bases. (After
Thomas; ca. ⅜ nat. size.)
An important point is the constant association with the flowers of
Taeniopteris vittata fronds, a species described in Vol. ii. and by most
palaeobotanists regarded as a Fern frond. Taeniopteris leaves occasionally
show a clean-cut base[1304] and in specimens described by Thomas there are
two small humps on the surface of the proximal end of the petiole which
represent vascular bundles. Humps of similar size occur on the leaf-scars of
stems which are believed to have borne both Taeniopteris leaves and
Page 519
Williamsoniella flowers. Fragments of the stems were found in association
with flowers: they are 7 mm.–2 cm. in diameter and frequently forked and
there is evidence that the flowers were borne at the forks, the shoot forming
a dichasial system. The habit of the plant is represented in fig. 573
reproduced from Mr Thomas’s paper.
Williamsoniella Lignieri (Nathorst).
This species described by Nathorst as Williamsonia? Lignieri from
Whitby is regarded by Thomas as a Williamsoniella. The stomata on the
microsporophylls agree with those of Taeniopteris and the spores obtained
from Nathorst’s flower-buds are like those of Williamsoniella coronata.
Evidence is adduced by Thomas in favour of regarding W. Lignieri as
bisexual and not unisexual as Nathorst supposed.
In habit Williamsoniella resembles Wielandiella: in the latter genus the
foliage-leaves were confined to portions of the stem near the forks, while in
Williamsoniella they were more uniformly scattered: Wielandiella bore
leaves of the Anomozamites form while Williamsoniella flowers are always
associated with Taeniopteris fronds. The much greater spore-output of
Williamsonia may, it is suggested by Thomas, be correlated with the
unisexual nature of the flowers of that species. The microsporophylls of
Williamsoniella differ in their more reduced form from the pinnate
microsporophylls of Williamsonia, e.g. W. spectabilis, and agree more
closely with those of Wielandiella. The microsporophylls of Williamsoniella
are free and not connate at the base as in Cycadeoidea and Williamsonia. In
its pyriform axis Williamsoniella resembles Williamsonia gigas and differs
from Williamsonia Leckenbyi in the possession of a sterile apical corona:
Williamsoniella has megasporophylls and microsporophylls both of which
appear to be functional, while in Cycadeoidea fully developed
microsporophylls occur in association with megasporophylls which are
immature and must have matured much later than the microsporophylls.
The new genus agrees with Williamsonia in its general features, but the
flowers are smaller and are characterised by the considerable reduction and
simplification of the male organs.
CYCADOCEPHALUS. Nathorst.
with flowers: they are 7 mm.–2 cm. in diameter and frequently forked and
there is evidence that the flowers were borne at the forks, the shoot forming
a dichasial system. The habit of the plant is represented in fig. 573
reproduced from Mr Thomas’s paper.
Williamsoniella Lignieri (Nathorst).
This species described by Nathorst as Williamsonia? Lignieri from
Whitby is regarded by Thomas as a Williamsoniella. The stomata on the
microsporophylls agree with those of Taeniopteris and the spores obtained
from Nathorst’s flower-buds are like those of Williamsoniella coronata.
Evidence is adduced by Thomas in favour of regarding W. Lignieri as
bisexual and not unisexual as Nathorst supposed.
In habit Williamsoniella resembles Wielandiella: in the latter genus the
foliage-leaves were confined to portions of the stem near the forks, while in
Williamsoniella they were more uniformly scattered: Wielandiella bore
leaves of the Anomozamites form while Williamsoniella flowers are always
associated with Taeniopteris fronds. The much greater spore-output of
Williamsonia may, it is suggested by Thomas, be correlated with the
unisexual nature of the flowers of that species. The microsporophylls of
Williamsoniella differ in their more reduced form from the pinnate
microsporophylls of Williamsonia, e.g. W. spectabilis, and agree more
closely with those of Wielandiella. The microsporophylls of Williamsoniella
are free and not connate at the base as in Cycadeoidea and Williamsonia. In
its pyriform axis Williamsoniella resembles Williamsonia gigas and differs
from Williamsonia Leckenbyi in the possession of a sterile apical corona:
Williamsoniella has megasporophylls and microsporophylls both of which
appear to be functional, while in Cycadeoidea fully developed
microsporophylls occur in association with megasporophylls which are
immature and must have matured much later than the microsporophylls.
The new genus agrees with Williamsonia in its general features, but the
flowers are smaller and are characterised by the considerable reduction and
simplification of the male organs.
CYCADOCEPHALUS. Nathorst.
Page 520
This genus was founded[1305] on a specimen from the Lower Rhaetic of
Scania, at first regarded as a megastrobilus and on further examination[1306]
found to be a collection of microsporophylls resembling those of
Williamsonia and Cycadeoidea. The type-species is Cycadocephalus
Sewardi, and a second species, C. minor, was subsequently discovered by
Dr Halle at a slightly higher horizon in the Rhaetic series. Prof. Nathorst’s
most recent account of the genus affords a striking illustration of the
possibilities of the method, which he has employed with conspicuous
success, of investigating carbonised fossils by means of cuticular
preparations.
Fig. 574. Cycadocephalus Sewardi. A, surface-view; a, appendages. B,
the same specimen, after the removal of some of the
microsporophylls, showing the appendages. C, section of a
microsporophyll showing the attachment of appendages. D, section
of an appendage. (After Nathorst. A, B, ¾ nat. size.)
Cycadocephalus Sewardi Nathorst.
Scania, at first regarded as a megastrobilus and on further examination[1306]
found to be a collection of microsporophylls resembling those of
Williamsonia and Cycadeoidea. The type-species is Cycadocephalus
Sewardi, and a second species, C. minor, was subsequently discovered by
Dr Halle at a slightly higher horizon in the Rhaetic series. Prof. Nathorst’s
most recent account of the genus affords a striking illustration of the
possibilities of the method, which he has employed with conspicuous
success, of investigating carbonised fossils by means of cuticular
preparations.
Fig. 574. Cycadocephalus Sewardi. A, surface-view; a, appendages. B,
the same specimen, after the removal of some of the
microsporophylls, showing the appendages. C, section of a
microsporophyll showing the attachment of appendages. D, section
of an appendage. (After Nathorst. A, B, ¾ nat. size.)
Cycadocephalus Sewardi Nathorst.
Page 521
The type-specimen consists of an oval cluster of 16–18 linear
microsporophylls, 9 cm. long, springing from a small circular disc formed
of their concrescent and narrow bases. The whole flower (fig. 574)
exclusive of the peduncle is 10 cm. long and 7 cm. broad. The portion of the
comparatively slender peduncle that is preserved shows no trace of leaf-
scars. In the middle of each linear microsporophyll is a keel-like midrib and
on either side of this is a series of linear appendages (fig. 574) 2–3 cm. long
lying in a radial direction towards the centre of the flower. These
appendages were originally thought to be seeds (fig. 574, a), but it was
suggested by Wieland that they might be synangia, the circle of leaves
being the male portion of a bisexual flower of the Cycadeoidea type.
Nathorst’s more complete investigation of the specimen confirmed the first
of these suggestions, but there is no evidence that there was an ovulate
receptacle in the centre of the flower. The appendages are attached by a
rather broad and slightly cordate base and are represented by a thin
carbonised cuticle of rectangular cells showing in one case a row of
imperfectly preserved stomata: on this are numerous groups of tetrahedral
microspores, about 55μ in diameter, which show a more or less well marked
arrangement in rows transverse to the long axis of the thin laminae. It is
clear from Nathorst’s researches that the groups were enclosed in loculi
bounded by thin-walled cells[1307], the loculi being in transverse rows on
each side of a midrib. Nathorst speaks of the appendages as synangia
characterised by the large number of the sporogenous compartments, and he
compares them especially to the fertile leaflets of Danaea elliptica as
described by Bower[1308], each appendage being comparable with a revolute
Danaea pinnule in which the edges of the lamina are united. This is
illustrated by the section of an appendage (fig. 574, D) reproduced from
Nathorst’s restoration of a Cycadocephalus microsporophyll. From a
morphological point of view it would seem more appropriate to speak of the
appendages as highly modified pinnules rather than synangia. The second
species, C. minor, agrees closely except in its smaller size with the type-
species. Nathorst regards Cycadocephalus as a unisexual flower differing
from those of Williamsonia and from the microsporophyll-verticils of
Cycadeoidea in the structure of the synangia and in the tetrahedral form of
the spores, though the latter feature he considers to be of secondary
importance, as both bilateral and radial spores occur in recent Marattiaceae.
He includes the genus in the Bennettitales but suggests that it should be
microsporophylls, 9 cm. long, springing from a small circular disc formed
of their concrescent and narrow bases. The whole flower (fig. 574)
exclusive of the peduncle is 10 cm. long and 7 cm. broad. The portion of the
comparatively slender peduncle that is preserved shows no trace of leaf-
scars. In the middle of each linear microsporophyll is a keel-like midrib and
on either side of this is a series of linear appendages (fig. 574) 2–3 cm. long
lying in a radial direction towards the centre of the flower. These
appendages were originally thought to be seeds (fig. 574, a), but it was
suggested by Wieland that they might be synangia, the circle of leaves
being the male portion of a bisexual flower of the Cycadeoidea type.
Nathorst’s more complete investigation of the specimen confirmed the first
of these suggestions, but there is no evidence that there was an ovulate
receptacle in the centre of the flower. The appendages are attached by a
rather broad and slightly cordate base and are represented by a thin
carbonised cuticle of rectangular cells showing in one case a row of
imperfectly preserved stomata: on this are numerous groups of tetrahedral
microspores, about 55μ in diameter, which show a more or less well marked
arrangement in rows transverse to the long axis of the thin laminae. It is
clear from Nathorst’s researches that the groups were enclosed in loculi
bounded by thin-walled cells[1307], the loculi being in transverse rows on
each side of a midrib. Nathorst speaks of the appendages as synangia
characterised by the large number of the sporogenous compartments, and he
compares them especially to the fertile leaflets of Danaea elliptica as
described by Bower[1308], each appendage being comparable with a revolute
Danaea pinnule in which the edges of the lamina are united. This is
illustrated by the section of an appendage (fig. 574, D) reproduced from
Nathorst’s restoration of a Cycadocephalus microsporophyll. From a
morphological point of view it would seem more appropriate to speak of the
appendages as highly modified pinnules rather than synangia. The second
species, C. minor, agrees closely except in its smaller size with the type-
species. Nathorst regards Cycadocephalus as a unisexual flower differing
from those of Williamsonia and from the microsporophyll-verticils of
Cycadeoidea in the structure of the synangia and in the tetrahedral form of
the spores, though the latter feature he considers to be of secondary
importance, as both bilateral and radial spores occur in recent Marattiaceae.
He includes the genus in the Bennettitales but suggests that it should be
Page 522
referred to a separate family as an indication of the possession of characters
which mark it off from Williamsonia, Weltrichia, Wielandiella, and
Cycadeoidea.
WELTRICHIA. Braun.
The name Weltrichia was given by Braun[1309] to some Rhaetic fossils
discovered by Weltrich near Culmbach in Franconia which represent
funnel-shaped structures, the lower part having the form of an incomplete
cup made of the concrescent bases of about 20 broadly linear segments
which in the upper part are separate lanceolate lobes each with a midrib and
slightly curved inwards at the apex. The whole, nearly 10 cm. long and 9
cm. in diameter at the upper edge, is very similar to the specimen of
Williamsonia spectabilis reproduced in fig. 551. Braun described three
species, but he realised the possibility that the different forms may be
different stages in the development of a single type Weltrichia mirabilis. He
assigned the genus to the Rhinantheae. Saporta[1310] drew attention to the
resemblance of Braun’s species to some examples of Williamsonia from
Yorkshire which he considered to be portions of a sterile appendage borne
at the apex of the flower. Some account is given of two types of funnel-like
structures connected with Williamsonia flowers on a previous page[1311]: one
of these has been shown by Nathorst to be a whorl of microsporophylls, and
it is with this that Weltrichia agrees. An important feature of Weltrichia is
the occurrence of short linear segments, 5–8 mm. long, attached to the inner
face of each of the free portions of the linear lobes: the lobes, or more
correctly the free apical portions of the fertile leaves, and their slender
appendages are compared by Nathorst[1312] to the microsporophylls and
relatively long synangia-bearing appendages of Cycadocephalus. These,
presumably fertile, segments of Weltrichia project in the flattened
impressions beyond the edges of the free lobes of the campanulate flower
and look like marginal teeth, though they are actually attached on each side
of the midrib and originally extended, as in Cycadocephalus, towards the
centre of the funnel-shaped flower. The examination of one of the type-
specimens acquired by Nathorst[1313] for the Stockholm Museum enabled
him to confirm his earlier conclusion that Weltrichia represents the male
portion of a flower, whether unisexual or bisexual cannot be definitely
determined, of a Bennettitalean plant. There is, as Nathorst states, a close
which mark it off from Williamsonia, Weltrichia, Wielandiella, and
Cycadeoidea.
WELTRICHIA. Braun.
The name Weltrichia was given by Braun[1309] to some Rhaetic fossils
discovered by Weltrich near Culmbach in Franconia which represent
funnel-shaped structures, the lower part having the form of an incomplete
cup made of the concrescent bases of about 20 broadly linear segments
which in the upper part are separate lanceolate lobes each with a midrib and
slightly curved inwards at the apex. The whole, nearly 10 cm. long and 9
cm. in diameter at the upper edge, is very similar to the specimen of
Williamsonia spectabilis reproduced in fig. 551. Braun described three
species, but he realised the possibility that the different forms may be
different stages in the development of a single type Weltrichia mirabilis. He
assigned the genus to the Rhinantheae. Saporta[1310] drew attention to the
resemblance of Braun’s species to some examples of Williamsonia from
Yorkshire which he considered to be portions of a sterile appendage borne
at the apex of the flower. Some account is given of two types of funnel-like
structures connected with Williamsonia flowers on a previous page[1311]: one
of these has been shown by Nathorst to be a whorl of microsporophylls, and
it is with this that Weltrichia agrees. An important feature of Weltrichia is
the occurrence of short linear segments, 5–8 mm. long, attached to the inner
face of each of the free portions of the linear lobes: the lobes, or more
correctly the free apical portions of the fertile leaves, and their slender
appendages are compared by Nathorst[1312] to the microsporophylls and
relatively long synangia-bearing appendages of Cycadocephalus. These,
presumably fertile, segments of Weltrichia project in the flattened
impressions beyond the edges of the free lobes of the campanulate flower
and look like marginal teeth, though they are actually attached on each side
of the midrib and originally extended, as in Cycadocephalus, towards the
centre of the funnel-shaped flower. The examination of one of the type-
specimens acquired by Nathorst[1313] for the Stockholm Museum enabled
him to confirm his earlier conclusion that Weltrichia represents the male
portion of a flower, whether unisexual or bisexual cannot be definitely
determined, of a Bennettitalean plant. There is, as Nathorst states, a close
Page 523
agreement in plan between Weltrichia, Cycadocephalus, and Williamsonia,
and indeed it is not clear in what respects Weltrichia is sufficiently distinct
from Cycadocephalus to be retained as a separate genus. Our knowledge of
Weltrichia is, however, less complete than in the case of Cycadocephalus
and Williamsonia. It is noteworthy that Braun’s specimens and those on
which Cycadocephalus was founded were obtained from Rhaetic rocks. An
account of Weltrichia has also been published by Schuster[1314] who differs
from Nathorst in his interpretation of the type-specimens: he considers that
another fossil described by Braun and named by him Palaeoxyris
microrhombea is the central, female, portion of a Weltrichia flower, a view
that is not supported by any substantial evidence. The specimens referred by
Braun to Palaeoxyris and afterwards transferred by Schimper[1315] to the
genus Lepidanthium are too obscurely preserved to be determined with any
degree of confidence, and their connexion with Weltrichia is purely
hypothetical. With Weltrichia Schuster also connects the fronds known as
Otozamites brevifolius Braun and some impressions of stems, combining all
in a restoration of a complete Weltrichia plant which rests more on
imagination than on fact. Attention has elsewhere[1316] been called to some
wholly misleading and incorrect statements made by Schuster which vitiate
the value of his descriptions.
Saporta[1317] described a species of Weltrichia, W. Fabrei. from French
Rhaetic strata at Mende (Lozère) which bears at least a close superficial
resemblance to Williamsonia spectabilis, and the same author founded
another species, Weltrichia oolithica, on a drawing by Zigno of a specimen
from Jurassic rocks in Italy; but this appears to be too imperfect for accurate
identification.
All that can be said as to the nature of Weltrichia, as illustrated by the
type-species, is that it represents a Rhaetic example of a verticil of
microsporophylls very similar to those of Williamsonia and
Cycadocephalus, if not generically identical with the latter form.
and indeed it is not clear in what respects Weltrichia is sufficiently distinct
from Cycadocephalus to be retained as a separate genus. Our knowledge of
Weltrichia is, however, less complete than in the case of Cycadocephalus
and Williamsonia. It is noteworthy that Braun’s specimens and those on
which Cycadocephalus was founded were obtained from Rhaetic rocks. An
account of Weltrichia has also been published by Schuster[1314] who differs
from Nathorst in his interpretation of the type-specimens: he considers that
another fossil described by Braun and named by him Palaeoxyris
microrhombea is the central, female, portion of a Weltrichia flower, a view
that is not supported by any substantial evidence. The specimens referred by
Braun to Palaeoxyris and afterwards transferred by Schimper[1315] to the
genus Lepidanthium are too obscurely preserved to be determined with any
degree of confidence, and their connexion with Weltrichia is purely
hypothetical. With Weltrichia Schuster also connects the fronds known as
Otozamites brevifolius Braun and some impressions of stems, combining all
in a restoration of a complete Weltrichia plant which rests more on
imagination than on fact. Attention has elsewhere[1316] been called to some
wholly misleading and incorrect statements made by Schuster which vitiate
the value of his descriptions.
Saporta[1317] described a species of Weltrichia, W. Fabrei. from French
Rhaetic strata at Mende (Lozère) which bears at least a close superficial
resemblance to Williamsonia spectabilis, and the same author founded
another species, Weltrichia oolithica, on a drawing by Zigno of a specimen
from Jurassic rocks in Italy; but this appears to be too imperfect for accurate
identification.
All that can be said as to the nature of Weltrichia, as illustrated by the
type-species, is that it represents a Rhaetic example of a verticil of
microsporophylls very similar to those of Williamsonia and
Cycadocephalus, if not generically identical with the latter form.
Page 524
Page 525
CHAPTER XXXVIII.
CYCADOPHYTA.
I. Cycadean Stems other than Cycadeoidea.
Most of the stems now under consideration are represented by casts or
impressions and afford no information with regard to anatomical characters.
They are in many cases more slender and less tuberous than typical
Cycadeoideas, and a few are characterised by an irregular form of
branching, as is shown in some specimens of pith-casts from Wealden strata
in Tilgate Forest figured by Mantell[1318] and now in the British Museum.
The genus Wielandiella[1319] (fig. 566) is an altogether distinct type
represented by flowers as well as vegetative organs. Several generic names
have been proposed for Cycadean stems agreeing with those of many recent
Cycads in the possession of an armour of persistent leaf-bases, but
distinguished from Cycadeoidea in the absence of any fertile lateral shoots
intercalated among the petiole-bases. It is, however, impossible in most
cases to give any satisfactory definition by which these genera can be
distinguished from one another; the characters employed by Carruthers[1320],
Saporta[1321], and other authors are of comparatively little importance as
trustworthy criteria and to a large extent are merely the expression of
different states of preservation or of differences in age. Attention has
elsewhere been called to the absence of any clear dividing line between
stems referred to Bucklandia, Yatesia, Fittonia and Cylindropodium. The
species Cycadeoidea gigantea described on a previous page affords an
instructive example of the difficulty of drawing a generic distinction
between certain types of Cycadean stems: in habit, in the form and structure
of the leaf-bases, and in the ramenta this species is identical with other
species of Cycadeoidea, but it differs in the absence of lateral fertile shoots,
a feature that may have no morphological significance. It has already been
pointed out that the absence of flowers intercalated among the leaf-bases
may simply mean that the plant had not reached the stage of flower-
production, or their absence may be due to some unfavourable conditions.
Similarly the stems for which Saporta proposed the generic name
CYCADOPHYTA.
I. Cycadean Stems other than Cycadeoidea.
Most of the stems now under consideration are represented by casts or
impressions and afford no information with regard to anatomical characters.
They are in many cases more slender and less tuberous than typical
Cycadeoideas, and a few are characterised by an irregular form of
branching, as is shown in some specimens of pith-casts from Wealden strata
in Tilgate Forest figured by Mantell[1318] and now in the British Museum.
The genus Wielandiella[1319] (fig. 566) is an altogether distinct type
represented by flowers as well as vegetative organs. Several generic names
have been proposed for Cycadean stems agreeing with those of many recent
Cycads in the possession of an armour of persistent leaf-bases, but
distinguished from Cycadeoidea in the absence of any fertile lateral shoots
intercalated among the petiole-bases. It is, however, impossible in most
cases to give any satisfactory definition by which these genera can be
distinguished from one another; the characters employed by Carruthers[1320],
Saporta[1321], and other authors are of comparatively little importance as
trustworthy criteria and to a large extent are merely the expression of
different states of preservation or of differences in age. Attention has
elsewhere been called to the absence of any clear dividing line between
stems referred to Bucklandia, Yatesia, Fittonia and Cylindropodium. The
species Cycadeoidea gigantea described on a previous page affords an
instructive example of the difficulty of drawing a generic distinction
between certain types of Cycadean stems: in habit, in the form and structure
of the leaf-bases, and in the ramenta this species is identical with other
species of Cycadeoidea, but it differs in the absence of lateral fertile shoots,
a feature that may have no morphological significance. It has already been
pointed out that the absence of flowers intercalated among the leaf-bases
may simply mean that the plant had not reached the stage of flower-
production, or their absence may be due to some unfavourable conditions.
Similarly the stems for which Saporta proposed the generic name
Page 526
Clathropodium agree in every respect with Cycadeoidea except in the
absence, apparent or real, of lateral flowering branches. Such types as
Clathropodium foratum Sap. and C. sarlatense Sap.[1322], the latter probably
from Upper Jurassic beds and the former from an unknown locality, should
be included in the genus Cycadeoidea. The stem referred by Saporta to his
genus Platylepis as P. micromyela[1323] was originally assigned to
Cycadeoidea and more recently Lignier has wisely adopted the original
generic name. The generic term Bolpopodium, also instituted by
Saporta[1324], is applied to small tuberous stems which appear to be identical
with the Cycadeoidea type.
Having regard to the meagre data supplied by casts of stems preserved in
various stages of defoliation, and in view of the impossibility of drawing
other than purely arbitrary generic distinctions, it is preferable to employ
one generic name in a liberal sense for stems that there is good reason to
regard as plants that cannot reasonably be referred to Cycadeoidea. The
name Bucklandia is thus employed, and a few examples are described in
illustration of the external features of stems that are undoubtedly Cycadean
but in most cases readily distinguished from Cycadeoidea. There are
substantial grounds for stating that plants which bore flowers of the
Williamsonia type possessed stems having the characters of Bucklandia. It
should, however, be remembered that we cannot always draw a clearly
defined distinction between flowers included in Williamsonia and
Bennettites, or Cycadeoidea, particularly when they are represented only by
detached ovulate strobili as in Cycadeoidea (Bennettites) Morierei and
Williamsonia scotica.
BUCKLANDIA. Presl.
Bucklandia was proposed by Presl[1325] for a plant described by
Mantell[1326] from the Wealden of Tilgate Forest and compared by him to the
Euphorbiaceae and arborescent Ferns; the same generic name was given by
Robert Brown in 1832 to a recent member of the Hamamelidaceae. Stokes
and Webb[1327] referred the same fossil to Clathraria, a name applied by
Brongniart[1328] to certain types of Sigillarian stems and afterwards adopted
by him for the Tilgate Forest species, C. Lyelli. Presl ‘with remarkable
discrimination’ recognised the Cycadean nature of the specimen.
Carruthers[1329] in his definition of Bucklandia includes a statement as to the
nature of the carpellary leaves and suggests that a cone associated with the
absence, apparent or real, of lateral flowering branches. Such types as
Clathropodium foratum Sap. and C. sarlatense Sap.[1322], the latter probably
from Upper Jurassic beds and the former from an unknown locality, should
be included in the genus Cycadeoidea. The stem referred by Saporta to his
genus Platylepis as P. micromyela[1323] was originally assigned to
Cycadeoidea and more recently Lignier has wisely adopted the original
generic name. The generic term Bolpopodium, also instituted by
Saporta[1324], is applied to small tuberous stems which appear to be identical
with the Cycadeoidea type.
Having regard to the meagre data supplied by casts of stems preserved in
various stages of defoliation, and in view of the impossibility of drawing
other than purely arbitrary generic distinctions, it is preferable to employ
one generic name in a liberal sense for stems that there is good reason to
regard as plants that cannot reasonably be referred to Cycadeoidea. The
name Bucklandia is thus employed, and a few examples are described in
illustration of the external features of stems that are undoubtedly Cycadean
but in most cases readily distinguished from Cycadeoidea. There are
substantial grounds for stating that plants which bore flowers of the
Williamsonia type possessed stems having the characters of Bucklandia. It
should, however, be remembered that we cannot always draw a clearly
defined distinction between flowers included in Williamsonia and
Bennettites, or Cycadeoidea, particularly when they are represented only by
detached ovulate strobili as in Cycadeoidea (Bennettites) Morierei and
Williamsonia scotica.
BUCKLANDIA. Presl.
Bucklandia was proposed by Presl[1325] for a plant described by
Mantell[1326] from the Wealden of Tilgate Forest and compared by him to the
Euphorbiaceae and arborescent Ferns; the same generic name was given by
Robert Brown in 1832 to a recent member of the Hamamelidaceae. Stokes
and Webb[1327] referred the same fossil to Clathraria, a name applied by
Brongniart[1328] to certain types of Sigillarian stems and afterwards adopted
by him for the Tilgate Forest species, C. Lyelli. Presl ‘with remarkable
discrimination’ recognised the Cycadean nature of the specimen.
Carruthers[1329] in his definition of Bucklandia includes a statement as to the
nature of the carpellary leaves and suggests that a cone associated with the
Page 527
stems may be a staminate strobilus: the cone is undoubtedly a megastrobilus
of an Araucarian plant and there is no evidence with regard to the nature of
either the male or female reproductive organs in the material that he
describes though, as already pointed out, there are reasons for believing that
Williamsonia flowers were borne on branches of Bucklandia stems. The
flowering shoots were not short and intercalated among the petiole-bases as
in Cycadeoidea with the strobili barely projecting beyond the surface of the
leaf-base armour, but they formed comparatively long branches, sometimes
forked, at the apex of the main stem (cf. figs. 541–543).
Bucklandia is usually represented by casts, from Rhaetic to Lower
Cretaceous strata, differing from Cycadeoidea in the absence of numerous
axillary short fertile shoots, in the more slender form and greater length of
the stems, and in the less uniform size of the persistent leaf-bases which
assume various forms. Some of the specimens reach a length of 4 feet and
afford evidence of occasional branching: the surface is covered with leaf-
bases preserved as imbricate, broad, and obtuse or truncate scales (fig. 575),
or as slightly convex polygonal areas in some cases showing a tendency
towards an irregular zonal arrangement of larger and smaller leaf-bases (fig.
576). Within the armour of leaf-bases there may be a cast of the large pith
the surface-features of which are practically identical with the cast of a
recent pith reproduced in fig. 398. Casts of the pith preserved as separate
fossils are included in the genus Cycadeomyelon.
There is evidence of the occurrence of more than one zone of vascular
tissue in a stem from Lower Greensand beds of Bedfordshire described by
Carruthers as Yatesia Morrisii[1330] (= Bucklandia Yatesii), and Dr Stopes[1331]
has recently described a species, B. buzzardensis (fig. 578), with several
zones of conducting tissue. This feature has not so far been satisfactorily
demonstrated in Cycadeoidea. An Indian species, Bucklandia indica, shows
that the secondary xylem is more compact than in typical Cycadeoidea
stems, and the tracheids have multiseriate pitting.
Two long and narrow stems figured by Nathorst from the Rhaetic of
Scania as Bucklandia Saportana[1332] differ from other species in the
irregular arrangement of the leaf-bases which in certain regions are
crowded as in the typical example of the genus shown in fig. 576, but in the
intervening portions of the stem they are few in number and widely
separated by the finely striated bark. This type, though similar to some
of an Araucarian plant and there is no evidence with regard to the nature of
either the male or female reproductive organs in the material that he
describes though, as already pointed out, there are reasons for believing that
Williamsonia flowers were borne on branches of Bucklandia stems. The
flowering shoots were not short and intercalated among the petiole-bases as
in Cycadeoidea with the strobili barely projecting beyond the surface of the
leaf-base armour, but they formed comparatively long branches, sometimes
forked, at the apex of the main stem (cf. figs. 541–543).
Bucklandia is usually represented by casts, from Rhaetic to Lower
Cretaceous strata, differing from Cycadeoidea in the absence of numerous
axillary short fertile shoots, in the more slender form and greater length of
the stems, and in the less uniform size of the persistent leaf-bases which
assume various forms. Some of the specimens reach a length of 4 feet and
afford evidence of occasional branching: the surface is covered with leaf-
bases preserved as imbricate, broad, and obtuse or truncate scales (fig. 575),
or as slightly convex polygonal areas in some cases showing a tendency
towards an irregular zonal arrangement of larger and smaller leaf-bases (fig.
576). Within the armour of leaf-bases there may be a cast of the large pith
the surface-features of which are practically identical with the cast of a
recent pith reproduced in fig. 398. Casts of the pith preserved as separate
fossils are included in the genus Cycadeomyelon.
There is evidence of the occurrence of more than one zone of vascular
tissue in a stem from Lower Greensand beds of Bedfordshire described by
Carruthers as Yatesia Morrisii[1330] (= Bucklandia Yatesii), and Dr Stopes[1331]
has recently described a species, B. buzzardensis (fig. 578), with several
zones of conducting tissue. This feature has not so far been satisfactorily
demonstrated in Cycadeoidea. An Indian species, Bucklandia indica, shows
that the secondary xylem is more compact than in typical Cycadeoidea
stems, and the tracheids have multiseriate pitting.
Two long and narrow stems figured by Nathorst from the Rhaetic of
Scania as Bucklandia Saportana[1332] differ from other species in the
irregular arrangement of the leaf-bases which in certain regions are
crowded as in the typical example of the genus shown in fig. 576, but in the
intervening portions of the stem they are few in number and widely
separated by the finely striated bark. This type, though similar to some
Page 528
specimens of English, Mexican, and Indian Bucklandias in the zonal
differences in the leaf-bases, represents an extreme case of the alternation of
smaller and crowded and larger and scattered leaf-scars. It is by no means
unlikely that Bucklandia Saportana forms a transition between Bucklandia
and the stem of Wielandiella described by Nathorst from the same region:
in Wielandiella the leaf-scars are concentrated at the region of forking but a
few occur elsewhere: in B. Saportana there is no evidence of branching and
in this respect it differs from Wielandiella.
Bucklandia anomala (Stokes and Webb).
This species, from Wealden beds in Sussex, was first described by Stokes
and Webb[1333] as Clathraria anomala, and the same type was figured by
Mantell and other authors as Clathraria Lyelli. The specimens referred by
Carruthers to Bucklandia anomala and B. Mantelli[1334] do not exhibit any
well defined specific differences, and there would seem to be no reason for
retaining both specific names. The petiole-bases are usually sub-rhomboidal
in form and convex or flat, but in some stems more of each petiole is
preserved and the surface is covered with broad imbricate scales (fig. 575)
similar to some of the detached scales described under the generic name
Cycadolepis. Pith-casts occur both in connexion with the Bucklandia stems
and as detached specimens. The leaf-bases often show an irregular zonation
of smaller and larger rhomboidal areas. The pith-cast in the lower part of
the specimen from the Wealden of Cuckfield in Sussex shown in fig. 575 is
5 × 3·5 cm. in diameter.
differences in the leaf-bases, represents an extreme case of the alternation of
smaller and crowded and larger and scattered leaf-scars. It is by no means
unlikely that Bucklandia Saportana forms a transition between Bucklandia
and the stem of Wielandiella described by Nathorst from the same region:
in Wielandiella the leaf-scars are concentrated at the region of forking but a
few occur elsewhere: in B. Saportana there is no evidence of branching and
in this respect it differs from Wielandiella.
Bucklandia anomala (Stokes and Webb).
This species, from Wealden beds in Sussex, was first described by Stokes
and Webb[1333] as Clathraria anomala, and the same type was figured by
Mantell and other authors as Clathraria Lyelli. The specimens referred by
Carruthers to Bucklandia anomala and B. Mantelli[1334] do not exhibit any
well defined specific differences, and there would seem to be no reason for
retaining both specific names. The petiole-bases are usually sub-rhomboidal
in form and convex or flat, but in some stems more of each petiole is
preserved and the surface is covered with broad imbricate scales (fig. 575)
similar to some of the detached scales described under the generic name
Cycadolepis. Pith-casts occur both in connexion with the Bucklandia stems
and as detached specimens. The leaf-bases often show an irregular zonation
of smaller and larger rhomboidal areas. The pith-cast in the lower part of
the specimen from the Wealden of Cuckfield in Sussex shown in fig. 575 is
5 × 3·5 cm. in diameter.
Page 529
Fig. 575. Bucklandia anomala. (British Museum, No. V. 3690; rather
less than natural size.)
Bucklandia Ruffordi Seward.
This species, from the Wealden beds on the Sussex coast[1335], was
originally described as Fittonia Ruffordi, but in the absence of any well
defined distinctive features that can be regarded as of morphological
significance it is better to include it in Bucklandia. The species affords a
good example of a long and narrow type of stem, one specimen reaching a
length of nearly 80 cm. with a breadth of about 10 cm.; the surface is
covered with persistent leaf-bases 1·7 cm. in depth with a scar agreeing in
less than natural size.)
Bucklandia Ruffordi Seward.
This species, from the Wealden beds on the Sussex coast[1335], was
originally described as Fittonia Ruffordi, but in the absence of any well
defined distinctive features that can be regarded as of morphological
significance it is better to include it in Bucklandia. The species affords a
good example of a long and narrow type of stem, one specimen reaching a
length of nearly 80 cm. with a breadth of about 10 cm.; the surface is
covered with persistent leaf-bases 1·7 cm. in depth with a scar agreeing in
Page 530
size and shape with the base of a frond of Otozamites Goeppertianus
(Dunk.)[1336] found in the same beds. There is no indication of any
alternation of large and small leaf-bases, and the species is characterised by
the uniform size and relatively greater depth in a vertical direction of the
leaf-base areas. In all probability the stem bore fertile branches similar to
those of Williamsonia gigas with flowers of the Williamsonia type: the
fronds may have been those known as Otozamites Goeppertianus, but this
has not been demonstrated. A stem described by Carruthers from the Lias of
Lyme Regis as Yatesia gracilis[1337] and afterwards included by me in
Cycadeoidea[1338] is very similar to B. Ruffordi in its long and narrow form
and in the shape of the leaf-bases; it should be transferred to Bucklandia as
B. gracilis (Carr.).
Bucklandia Milleriana Carruthers.
This species was founded on a cast from Lower Oolite beds at Brora in
Sutherlandshire[1339] characterised by leaf-bases very similar to those of B.
anomala but smaller. Casts from the same locality were named by
Carruthers Yatesia crassa and Y. Joassiana[1340], but an examination of
specimens in the Dunrobin Museum leads me to regard these forms as
indistinguishable from B. Milleriana. The specimen reproduced in fig. 576
from the Great Oolite of Brora illustrates the external characters of a typical
stem and shows the variation in the size of the leaf-bases. A portion of the
pith-cast is exposed in the lower part of the stem.
(Dunk.)[1336] found in the same beds. There is no indication of any
alternation of large and small leaf-bases, and the species is characterised by
the uniform size and relatively greater depth in a vertical direction of the
leaf-base areas. In all probability the stem bore fertile branches similar to
those of Williamsonia gigas with flowers of the Williamsonia type: the
fronds may have been those known as Otozamites Goeppertianus, but this
has not been demonstrated. A stem described by Carruthers from the Lias of
Lyme Regis as Yatesia gracilis[1337] and afterwards included by me in
Cycadeoidea[1338] is very similar to B. Ruffordi in its long and narrow form
and in the shape of the leaf-bases; it should be transferred to Bucklandia as
B. gracilis (Carr.).
Bucklandia Milleriana Carruthers.
This species was founded on a cast from Lower Oolite beds at Brora in
Sutherlandshire[1339] characterised by leaf-bases very similar to those of B.
anomala but smaller. Casts from the same locality were named by
Carruthers Yatesia crassa and Y. Joassiana[1340], but an examination of
specimens in the Dunrobin Museum leads me to regard these forms as
indistinguishable from B. Milleriana. The specimen reproduced in fig. 576
from the Great Oolite of Brora illustrates the external characters of a typical
stem and shows the variation in the size of the leaf-bases. A portion of the
pith-cast is exposed in the lower part of the stem.
Page 531
Fig. 576. Bucklandia Milleriana. Brora, Scotland. (Manchester
Museum, L. 7229. ca. ½ nat. size.)
Bucklandia Yatesii (Carruthers).
This type from the Lower Greensand of Bedfordshire (fig. 577) was
described by Carruthers as Cycadeoidea Yatesii and subsequently named
Yatesia Morrisii[1341]. Ward expressed the opinion that the name should be
Yatesia Yatesii, but as Bucklandia is now used to include Yatesia this
combination is fortunately avoided. The stem is cylindrical, 20–30 cm. long
Museum, L. 7229. ca. ½ nat. size.)
Bucklandia Yatesii (Carruthers).
This type from the Lower Greensand of Bedfordshire (fig. 577) was
described by Carruthers as Cycadeoidea Yatesii and subsequently named
Yatesia Morrisii[1341]. Ward expressed the opinion that the name should be
Yatesia Yatesii, but as Bucklandia is now used to include Yatesia this
combination is fortunately avoided. The stem is cylindrical, 20–30 cm. long
Page 532
and 12 cm. in diameter, covered with rhomboidal leaf-bases separated from
one another by a ramental reticulum. There are two concentric vascular
cylinders as stated by Carruthers. In a recent account of this species Dr
Stopes[1342] adds further details: the xylem-cylinders are 5–8 mm. wide and
the tracheids occur in single rows or there may be bands 4–5 elements
broad; the circular bordered pits are uniseriate or in two alternate series.
The medullary rays are broad but the cells are not preserved. The pith-cast
is of the usual Cycadean type.
Fig. 577. Bucklandia Yatesii. Type-specimen in the British Museum.
one another by a ramental reticulum. There are two concentric vascular
cylinders as stated by Carruthers. In a recent account of this species Dr
Stopes[1342] adds further details: the xylem-cylinders are 5–8 mm. wide and
the tracheids occur in single rows or there may be bands 4–5 elements
broad; the circular bordered pits are uniseriate or in two alternate series.
The medullary rays are broad but the cells are not preserved. The pith-cast
is of the usual Cycadean type.
Fig. 577. Bucklandia Yatesii. Type-specimen in the British Museum.
Page 533
The type-specimen was presented by the Cirencester College to the
British Museum.
Fig. 578. Bucklandia buzzardensis. Rough sketch of a block of wood
showing parts of at least eight concentrically arranged rings of
secondary wood. (After Stopes; × ⅔.)
Bucklandia buzzardensis (Stopes).
This species, from Lower Greensand beds at Leighton Buzzard and
believed to be derived from Wealden strata, is described by Dr Stopes[1343] as
Cycadeoidea buzzardensis. Though agreeing generally with B. Yatesii, the
stem is specifically separated on the ground that the petiole-bases are more
expanded laterally and because of the occurrence of several vascular
cylinders (fig. 578), sometimes as many as eight, each with a maximum
diameter of 1 cm. Dr Stopes thinks it possible that B. buzzardensis is an
older form of B. Yatesii.
British Museum.
Fig. 578. Bucklandia buzzardensis. Rough sketch of a block of wood
showing parts of at least eight concentrically arranged rings of
secondary wood. (After Stopes; × ⅔.)
Bucklandia buzzardensis (Stopes).
This species, from Lower Greensand beds at Leighton Buzzard and
believed to be derived from Wealden strata, is described by Dr Stopes[1343] as
Cycadeoidea buzzardensis. Though agreeing generally with B. Yatesii, the
stem is specifically separated on the ground that the petiole-bases are more
expanded laterally and because of the occurrence of several vascular
cylinders (fig. 578), sometimes as many as eight, each with a maximum
diameter of 1 cm. Dr Stopes thinks it possible that B. buzzardensis is an
older form of B. Yatesii.
Page 534
Bucklandia squamosa (Brongniart).
Sternberg first described this species as Conites Bucklandi[1344] and
regarded it as a cone bearing large imbricate cone-scales; it was named by
Brongniart Bucklandia squamosa[1345] and Carruthers[1346] retained this
designation. The type-specimen, in the Oxford Museum, from the
Stonesfield Slate is 18 cm. long, showing in the lower part a cast of the pith.
The surface of the stem is covered with thick imbricate petiole-bases very
like those on the stem of a recent Encephalartos.
Bucklandia (Fittonia) squamata (Carruthers).
Carruthers[1347] founded the genus Fittonia on a single specimen from the
Wealden beds of the Isle of Wight, separating it from Bucklandia on the
ground of the occurrence on a portion of the stem of large imbricate leaf-
bases which are at first reflexed and then ascending; the stem is also
broader and more tuberous than most species of Bucklandia. The type-
specimen, in the Museum of the Geological Survey (Jermyn street), bears a
close resemblance to a trunk of a recent Encephalartos, but the part of the
stem from which the imbricate stumps have fallen is practically identical
with a Bucklandia. As in certain recent Cycads the surface-features
probably changed with the age of the plant; when the foliage-leaves were
first shed a portion of the ascending petiole remained on the stem, and at a
later stage this was cut off leaving a clean-cut rhomboidal scar like those on
the Bucklandia shown in fig. 576. The difference between Fittonia and
Bucklandia may, therefore, be a question of age. While substituting
Bucklandia for Fittonia as the generic name the latter designation is added
in parentheses to denote the possession of certain features which, though
possibly of generic value, are not regarded as sufficiently important
morphologically to warrant generic recognition.
The type-specimen of Saporta’s species Fittonia insignis[1348], in the Paris
Museum, from the Oxfordian of Poitiers, appears hardly distinguishable
from F. squamata Carr. Another type with broader imbricate petiole stumps
is described by Saporta from the Portlandian near Boulogne as Fittonia
Rigauxi[1349].
Sternberg first described this species as Conites Bucklandi[1344] and
regarded it as a cone bearing large imbricate cone-scales; it was named by
Brongniart Bucklandia squamosa[1345] and Carruthers[1346] retained this
designation. The type-specimen, in the Oxford Museum, from the
Stonesfield Slate is 18 cm. long, showing in the lower part a cast of the pith.
The surface of the stem is covered with thick imbricate petiole-bases very
like those on the stem of a recent Encephalartos.
Bucklandia (Fittonia) squamata (Carruthers).
Carruthers[1347] founded the genus Fittonia on a single specimen from the
Wealden beds of the Isle of Wight, separating it from Bucklandia on the
ground of the occurrence on a portion of the stem of large imbricate leaf-
bases which are at first reflexed and then ascending; the stem is also
broader and more tuberous than most species of Bucklandia. The type-
specimen, in the Museum of the Geological Survey (Jermyn street), bears a
close resemblance to a trunk of a recent Encephalartos, but the part of the
stem from which the imbricate stumps have fallen is practically identical
with a Bucklandia. As in certain recent Cycads the surface-features
probably changed with the age of the plant; when the foliage-leaves were
first shed a portion of the ascending petiole remained on the stem, and at a
later stage this was cut off leaving a clean-cut rhomboidal scar like those on
the Bucklandia shown in fig. 576. The difference between Fittonia and
Bucklandia may, therefore, be a question of age. While substituting
Bucklandia for Fittonia as the generic name the latter designation is added
in parentheses to denote the possession of certain features which, though
possibly of generic value, are not regarded as sufficiently important
morphologically to warrant generic recognition.
The type-specimen of Saporta’s species Fittonia insignis[1348], in the Paris
Museum, from the Oxfordian of Poitiers, appears hardly distinguishable
from F. squamata Carr. Another type with broader imbricate petiole stumps
is described by Saporta from the Portlandian near Boulogne as Fittonia
Rigauxi[1349].
Page 535
Fig. 579. Bucklandia indica. A, side-view showing the leaf-bases and
attached petioles of Ptilophyllum, also (to the left) a fragment of a
detached Ptilophyllum leaf. B, transverse section showing the pith,
xylem cylinder, cortex, and sections of petioles. (British Museum;
nat. size.)
Bucklandia indica sp. nov.
Oldham and Morris[1350] and subsequently Feistmantel[1351] described some
specimens of Cycadean stems from the Rajmahal Hills of India of Lower
attached petioles of Ptilophyllum, also (to the left) a fragment of a
detached Ptilophyllum leaf. B, transverse section showing the pith,
xylem cylinder, cortex, and sections of petioles. (British Museum;
nat. size.)
Bucklandia indica sp. nov.
Oldham and Morris[1350] and subsequently Feistmantel[1351] described some
specimens of Cycadean stems from the Rajmahal Hills of India of Lower
Page 536
Jurassic age: the latter author regarded them as stems of Williamsonia
because of their association with flowers of that type, a conclusion fully
justified by the evidence. Feistmantel also called attention to the
resemblance of the Indian stems to specimens described from British strata
as Bucklandia and Yatesia. Although the Indian examples are very similar to
stems from Mexico discovered by Wieland[1352] and to some of the English
types, it seems desirable to refer to them under a specific name and I
therefore suggest the institution of the specific name indica, the type-
specimen being that represented in fig. 579. This specimen is particularly
interesting because it affords some information as to anatomical features
and is one of the few fossil stems preserved in organic connexion with
leaves (fig. 579, B). A short account of it was published in 1900[1353] and
more recently Miss Bancroft[1354] has made a fuller investigation of this and
other Indian specimens. The stem shown in fig. 579 from the Rajmahal
Hills, and now in the British Museum, bears fronds of Ptilophyllum
cutchense Morr., a type that appears to be indistinguishable from P. pecten;
and with similar stems from the same beds are associated flowers of
Williamsonia. Miss Bancroft describes a bract-covered shoot which agrees
very closely with those of English stems reproduced in figs. 541, 542. In
addition to the evidence based on close association, there is the more
important argument furnished by the discovery of ramental hairs like those
on the bracts of Williamsonia scotica and of anatomical characters in the
bracts similar to those in the Scotch strobilus. The persistent leaf-bases are
far from uniform in size; in this respect and in their form they agree closely
with those on Bucklandia stems from English and Mexican localities. The
secondary wood is more compact than in recent Cycads or in Cycadeoidea,
though it resembles that of Cycadeoidea micromyela; the medullary rays are
uniseriate and the tracheids have multiseriate bordered pits on their radial
walls instead of the scalariform pitting in the majority of Cycadeoidea
stems. Secretory canals are abundant in the parenchymatous ground-tissue;
the cambium and phloem are not preserved[1355].
The transparent nature of the silicified material rendered very difficult the
examination of the tissues, but enough was discovered to show that these
Indian stems are characterised by certain features, the more compact nature
of the secondary xylem and the presence of multiseriate pitting, which
distinguish them from the Cycadeoidea type. Further knowledge of the
anatomical features of the Williamsonia (Bucklandia) stems from other
because of their association with flowers of that type, a conclusion fully
justified by the evidence. Feistmantel also called attention to the
resemblance of the Indian stems to specimens described from British strata
as Bucklandia and Yatesia. Although the Indian examples are very similar to
stems from Mexico discovered by Wieland[1352] and to some of the English
types, it seems desirable to refer to them under a specific name and I
therefore suggest the institution of the specific name indica, the type-
specimen being that represented in fig. 579. This specimen is particularly
interesting because it affords some information as to anatomical features
and is one of the few fossil stems preserved in organic connexion with
leaves (fig. 579, B). A short account of it was published in 1900[1353] and
more recently Miss Bancroft[1354] has made a fuller investigation of this and
other Indian specimens. The stem shown in fig. 579 from the Rajmahal
Hills, and now in the British Museum, bears fronds of Ptilophyllum
cutchense Morr., a type that appears to be indistinguishable from P. pecten;
and with similar stems from the same beds are associated flowers of
Williamsonia. Miss Bancroft describes a bract-covered shoot which agrees
very closely with those of English stems reproduced in figs. 541, 542. In
addition to the evidence based on close association, there is the more
important argument furnished by the discovery of ramental hairs like those
on the bracts of Williamsonia scotica and of anatomical characters in the
bracts similar to those in the Scotch strobilus. The persistent leaf-bases are
far from uniform in size; in this respect and in their form they agree closely
with those on Bucklandia stems from English and Mexican localities. The
secondary wood is more compact than in recent Cycads or in Cycadeoidea,
though it resembles that of Cycadeoidea micromyela; the medullary rays are
uniseriate and the tracheids have multiseriate bordered pits on their radial
walls instead of the scalariform pitting in the majority of Cycadeoidea
stems. Secretory canals are abundant in the parenchymatous ground-tissue;
the cambium and phloem are not preserved[1355].
The transparent nature of the silicified material rendered very difficult the
examination of the tissues, but enough was discovered to show that these
Indian stems are characterised by certain features, the more compact nature
of the secondary xylem and the presence of multiseriate pitting, which
distinguish them from the Cycadeoidea type. Further knowledge of the
anatomical features of the Williamsonia (Bucklandia) stems from other
Page 537
localities might enable us to recognise these or other peculiarities as
constant distinguishing characters of Bucklandia in contrast to the
Cycadeoidea stems which bore the Bennettites type of flower.
Cycadeomyelon. Saporta.
Casts of the pith-cavity of Cycadean stems, like that shown in fig. 575
projecting beyond the armour of leaf-bases, are occasionally found as
separate fossils and cannot always be referred to a particular species of
stem. For such detached casts Saporta[1356] instituted the name
Cycadeomyelon: they are characterised by their comparatively large
diameter and by the possession of surface-features similar to those on the
corresponding cast from a recent Cycadean stem shown in fig. 398, namely
spirally disposed, more or less prominent, lozenge-shaped areas formed by
the sand or mud filling the cavities left on the decay of the parenchyma of
the broad medullary rays of a manoxylic stem. Occasionally a slit at the
lower end of a medullary ray area marks the position of the leaf-trace
bending outwards from the lower angle of the mesh in the xylem-lattice[1357].
Lignier figures part of a pith-cast of Cycadeomyelon Apperti[1358] in which
each medullary-ray area has a circular depression and not a slit extending
from the lower angle: this may indicate that the surface shown on the cast is
slightly external to the inner edge of the stele and in a plane where the leaf-
traces were embedded in the parenchyma of the rays and free from the
xylem-cylinder.
Large and branched examples of Cycadeomyelon were figured by some
of the earlier authors from English Wealden beds as species of
Clathraria[1359] and in many cases these are undoubtedly pith-casts of
Bucklandia stems: a similar cast is figured under this name by Schenk from
the Wealden of North Germany. From Liassic beds in Normandy Lignier
figures two species of Cycadeomyelon, C. Apperti and C. densecristatum.
The surface-features of Cycadeomyelon resemble those of the Palaeozoic
genus Tylodendron (see Vol. iv.), but in the latter genus the nodal swellings
are a characteristic peculiarity. Though medullary casts of this type are of
no great botanical importance and their specific distinctions are of little
value, it is safe to assume that broad medullary casts with comparatively
large lozenge-shaped areas belong to Cycadean stems, while narrower
constant distinguishing characters of Bucklandia in contrast to the
Cycadeoidea stems which bore the Bennettites type of flower.
Cycadeomyelon. Saporta.
Casts of the pith-cavity of Cycadean stems, like that shown in fig. 575
projecting beyond the armour of leaf-bases, are occasionally found as
separate fossils and cannot always be referred to a particular species of
stem. For such detached casts Saporta[1356] instituted the name
Cycadeomyelon: they are characterised by their comparatively large
diameter and by the possession of surface-features similar to those on the
corresponding cast from a recent Cycadean stem shown in fig. 398, namely
spirally disposed, more or less prominent, lozenge-shaped areas formed by
the sand or mud filling the cavities left on the decay of the parenchyma of
the broad medullary rays of a manoxylic stem. Occasionally a slit at the
lower end of a medullary ray area marks the position of the leaf-trace
bending outwards from the lower angle of the mesh in the xylem-lattice[1357].
Lignier figures part of a pith-cast of Cycadeomyelon Apperti[1358] in which
each medullary-ray area has a circular depression and not a slit extending
from the lower angle: this may indicate that the surface shown on the cast is
slightly external to the inner edge of the stele and in a plane where the leaf-
traces were embedded in the parenchyma of the rays and free from the
xylem-cylinder.
Large and branched examples of Cycadeomyelon were figured by some
of the earlier authors from English Wealden beds as species of
Clathraria[1359] and in many cases these are undoubtedly pith-casts of
Bucklandia stems: a similar cast is figured under this name by Schenk from
the Wealden of North Germany. From Liassic beds in Normandy Lignier
figures two species of Cycadeomyelon, C. Apperti and C. densecristatum.
The surface-features of Cycadeomyelon resemble those of the Palaeozoic
genus Tylodendron (see Vol. iv.), but in the latter genus the nodal swellings
are a characteristic peculiarity. Though medullary casts of this type are of
no great botanical importance and their specific distinctions are of little
value, it is safe to assume that broad medullary casts with comparatively
large lozenge-shaped areas belong to Cycadean stems, while narrower
Page 538
specimens with smaller lozenges are more likely to be pith-casts of
Coniferous stems.
Lester Ward[1360] instituted the genus Feistmantelia for some Lower
Cretaceous casts from the Black Hills which he compared with an Indian
fossil from Cutch described by Feistmantel as ‘the stem of a Coniferous
plant[1361],’ and with pith-casts figured by Stokes and Webb as Clathraria
anomala. It is impossible to determine the systematic position of such
imperfect specimens as that on which Ward founded his species F. oblonga:
they may, as Hollick and Jeffrey[1362] suggest, be casts of the bark of some
Conifer; there is certainly no good reason for connecting them with Cycads.
COLYMBETES. Stopes.
Colymbetes Edwardsi Stopes. This genus[1363] is founded on the inner
portion of a petrified trunk which was probably cylindrical and more than
12 cm. in diameter, consisting of a pith, 7·5 cm. in diameter, and part of a
vascular cylinder of remarkable structure. The type-specimen is of Aptian
age and may have come from Leighton Buzzard (Bedfordshire). The pith
(fig. 580, p) consists of large parenchymatous cells and numerous secretory
canals: the perimedullary zone, pm, is characterised by the occurrence of
loosely disposed tracheids in groups and radial rows pursuing a sinuous
longitudinal course in the accompanying parenchyma. The tracheids in this
region are small in diameter and have oval, scalariform, or circular pits.
Abutting on the perimedullary zone is the secondary xylem the inner edge
of which forms bays, and this is composed of alternating zones of vertical
and horizontal tracheids (fig. 580, y1–x5; fig. 581) with bordered,
scalariform, pits on their walls traversed by medullary rays generally
biseriate and from 4 to 30 cells deep. The disposition of the tracheids is
such as to render transverse and radial longitudinal sections practically
identical in appearance; the first zone of secondary xylem with its bayed
inner edge consists of vertically running elements; this is succeeded by a
zone in which the tracheids pursue a horizontal course, and beyond this
second zone is another band of vertical elements (fig. 581). ‘Where the one
zone passes into the next, a curving of the elements is frequently evident,
and in a few cases it is quite possible to trace a single radial series of
tracheids through an angle of 90° running in the same section, first as a
transverse and then as a vertical series. One and the same medullary ray
also can sometimes be followed, first in transverse and then in radial
Coniferous stems.
Lester Ward[1360] instituted the genus Feistmantelia for some Lower
Cretaceous casts from the Black Hills which he compared with an Indian
fossil from Cutch described by Feistmantel as ‘the stem of a Coniferous
plant[1361],’ and with pith-casts figured by Stokes and Webb as Clathraria
anomala. It is impossible to determine the systematic position of such
imperfect specimens as that on which Ward founded his species F. oblonga:
they may, as Hollick and Jeffrey[1362] suggest, be casts of the bark of some
Conifer; there is certainly no good reason for connecting them with Cycads.
COLYMBETES. Stopes.
Colymbetes Edwardsi Stopes. This genus[1363] is founded on the inner
portion of a petrified trunk which was probably cylindrical and more than
12 cm. in diameter, consisting of a pith, 7·5 cm. in diameter, and part of a
vascular cylinder of remarkable structure. The type-specimen is of Aptian
age and may have come from Leighton Buzzard (Bedfordshire). The pith
(fig. 580, p) consists of large parenchymatous cells and numerous secretory
canals: the perimedullary zone, pm, is characterised by the occurrence of
loosely disposed tracheids in groups and radial rows pursuing a sinuous
longitudinal course in the accompanying parenchyma. The tracheids in this
region are small in diameter and have oval, scalariform, or circular pits.
Abutting on the perimedullary zone is the secondary xylem the inner edge
of which forms bays, and this is composed of alternating zones of vertical
and horizontal tracheids (fig. 580, y1–x5; fig. 581) with bordered,
scalariform, pits on their walls traversed by medullary rays generally
biseriate and from 4 to 30 cells deep. The disposition of the tracheids is
such as to render transverse and radial longitudinal sections practically
identical in appearance; the first zone of secondary xylem with its bayed
inner edge consists of vertically running elements; this is succeeded by a
zone in which the tracheids pursue a horizontal course, and beyond this
second zone is another band of vertical elements (fig. 581). ‘Where the one
zone passes into the next, a curving of the elements is frequently evident,
and in a few cases it is quite possible to trace a single radial series of
tracheids through an angle of 90° running in the same section, first as a
transverse and then as a vertical series. One and the same medullary ray
also can sometimes be followed, first in transverse and then in radial
Page 539
longitudinal section, which later again turns to true transverse. The
inference is therefore drawn that there was but a single cambium, which had
periodic changes of direction.’ Leaf-traces (fig. 580, lt) are large and
numerous; they are spirally disposed and pass nearly straight through
successive xylem-zones: each trace consists of a small-celled ground-tissue
including stone-cells and patches of tracheids in more or less regular radial
rows. Tangential sections of the wood show that the tracheids follow a
sinuous course forming loops enclosing numerous medullary rays.
inference is therefore drawn that there was but a single cambium, which had
periodic changes of direction.’ Leaf-traces (fig. 580, lt) are large and
numerous; they are spirally disposed and pass nearly straight through
successive xylem-zones: each trace consists of a small-celled ground-tissue
including stone-cells and patches of tracheids in more or less regular radial
rows. Tangential sections of the wood show that the tracheids follow a
sinuous course forming loops enclosing numerous medullary rays.
Page 540
Fig. 580. Colymbetes Edwardsi. Transverse section showing ten
alternating zones of wood outside the perimedullary zone, pm; y1,
y2, etc., vertically running xylem series; x1, x2, etc., horizontally
running xylem series; p, pith; lt, leaf-traces. (After Stopes; × 2.)
alternating zones of wood outside the perimedullary zone, pm; y1,
y2, etc., vertically running xylem series; x1, x2, etc., horizontally
running xylem series; p, pith; lt, leaf-traces. (After Stopes; × 2.)
Page 541
Fig. 581. Colymbetes Edwardsi. Diagram of stem in transverse (A) and
radial longitudinal (B) section. p, pith; pm, perimedullary xylem;
b, bays of first, vertically running, secondary xylem; x1, x2, etc.,
zones of horizontally running secondary xylem cut transversely in
the radial and radially in the transverse section of the stem; y1, y2,
etc., longitudinally running xylem cut transversely in the
transverse and longitudinally in the radial section. (After Stopes.)
As the pith and xylem are the only tissues preserved it is on their
structure that any speculation as to affinity must be based. The close
arrangement of the leaf-traces (about 1 cm. apart), as Dr Stopes says,
indicates small leaf-bases, assuming that each leaf received a single trace.
In some respects the xylem and medullary rays resemble those of Cycads,
and the author of the genus includes it in the Cycadophyta; but as she points
out there are many peculiar features, and it is clearly impossible to assign
the new type to a more precisely defined position. The possibility of any
purely mechanical explanation of the course of the tracheids in the
alternating zones is ruled out by the straight course of the outgoing leaf-
traces, and it would seem that the cambium must have turned over at right-
angles at regular intervals during the growth of the stem.
radial longitudinal (B) section. p, pith; pm, perimedullary xylem;
b, bays of first, vertically running, secondary xylem; x1, x2, etc.,
zones of horizontally running secondary xylem cut transversely in
the radial and radially in the transverse section of the stem; y1, y2,
etc., longitudinally running xylem cut transversely in the
transverse and longitudinally in the radial section. (After Stopes.)
As the pith and xylem are the only tissues preserved it is on their
structure that any speculation as to affinity must be based. The close
arrangement of the leaf-traces (about 1 cm. apart), as Dr Stopes says,
indicates small leaf-bases, assuming that each leaf received a single trace.
In some respects the xylem and medullary rays resemble those of Cycads,
and the author of the genus includes it in the Cycadophyta; but as she points
out there are many peculiar features, and it is clearly impossible to assign
the new type to a more precisely defined position. The possibility of any
purely mechanical explanation of the course of the tracheids in the
alternating zones is ruled out by the straight course of the outgoing leaf-
traces, and it would seem that the cambium must have turned over at right-
angles at regular intervals during the growth of the stem.
Page 542
Cycadolepis. Saporta.
This name was used by Saporta[1364] for linear-lanceolate scales from
Upper Jurassic rocks in France which he compared with bud-scales of
recent Cycads. The imperfect scale described as Cycadolepis villosa bears a
striking resemblance to the hairy bracts of Williamsonia and may well
belong to that genus. Saporta’s term may be usefully employed in a more
extended sense, including not only lanceolate scales but larger and much
broader scales resembling the flattened petiole-bases on stems of
Macrozamia, Encephalartos, and some other recent genera, as well as
detached carpellary scales, other than Cycadospadix, and microsporophylls
which cannot be assigned to a particular stem. Two qualifying subgeneric
terms have been proposed[1365]:
i. Cycadolepis (Dory-Cycadolepis). Scales more or less linear-lanceolate
like those described by Saporta and a specimen from Jurassic rocks of India
named by Feistmantel[1366] Cycadolepis pilosa. This type of Cycadolepis
may be identical with the bracts of Williamsonia flowers, though in the
absence of any definite evidence of such affinity the provisional generic
name is more appropriate.
ii. Cycadolepis (Eury-Cycadolepis). Broadly oval or orbicular thick
scales (figs. 582, 583), the broadest part being frequently nearer the distal
than the proximal end. These larger scales though usually found as detached
fossils have in one instance been obtained attached to an imperfectly
preserved stem.
This name was used by Saporta[1364] for linear-lanceolate scales from
Upper Jurassic rocks in France which he compared with bud-scales of
recent Cycads. The imperfect scale described as Cycadolepis villosa bears a
striking resemblance to the hairy bracts of Williamsonia and may well
belong to that genus. Saporta’s term may be usefully employed in a more
extended sense, including not only lanceolate scales but larger and much
broader scales resembling the flattened petiole-bases on stems of
Macrozamia, Encephalartos, and some other recent genera, as well as
detached carpellary scales, other than Cycadospadix, and microsporophylls
which cannot be assigned to a particular stem. Two qualifying subgeneric
terms have been proposed[1365]:
i. Cycadolepis (Dory-Cycadolepis). Scales more or less linear-lanceolate
like those described by Saporta and a specimen from Jurassic rocks of India
named by Feistmantel[1366] Cycadolepis pilosa. This type of Cycadolepis
may be identical with the bracts of Williamsonia flowers, though in the
absence of any definite evidence of such affinity the provisional generic
name is more appropriate.
ii. Cycadolepis (Eury-Cycadolepis). Broadly oval or orbicular thick
scales (figs. 582, 583), the broadest part being frequently nearer the distal
than the proximal end. These larger scales though usually found as detached
fossils have in one instance been obtained attached to an imperfectly
preserved stem.
Page 543
Fig. 583. Cycadolepis
(Eury-Cycadolepis) sp.
Scale from the Wealden
beds of Sussex. (British
Museum, No. V. 2131a;
nat. size.)
Fig. 582. Cycadolepis (Eury-
Cycadolepis) sp. From the
Wealden beds of Sussex. (Brit.
Mus. No. V. 2799.)
Eury-Cycadolepis sp.
This type of scale, represented by specimens from the Wealden of
Sussex[1367] (figs. 582, 583), reaches a length of 13 cm. and a breadth of 7
cm. and is sometimes almost orbicular. The lamina is convex but shows no
definite venation and bears a close resemblance to the scale-like petiole-
stumps on an old stem of Macrozamia. On some of the smaller specimens
(fig. 583) several forked veins extend vertically from the broad base. Since
(Eury-Cycadolepis) sp.
Scale from the Wealden
beds of Sussex. (British
Museum, No. V. 2131a;
nat. size.)
Fig. 582. Cycadolepis (Eury-
Cycadolepis) sp. From the
Wealden beds of Sussex. (Brit.
Mus. No. V. 2799.)
Eury-Cycadolepis sp.
This type of scale, represented by specimens from the Wealden of
Sussex[1367] (figs. 582, 583), reaches a length of 13 cm. and a breadth of 7
cm. and is sometimes almost orbicular. The lamina is convex but shows no
definite venation and bears a close resemblance to the scale-like petiole-
stumps on an old stem of Macrozamia. On some of the smaller specimens
(fig. 583) several forked veins extend vertically from the broad base. Since
Page 544
these specimens were first described additional examples have been
discovered in the Wealden beds of Sussex, some of which are attached to a
piece of stem[1368] in such a manner as to give support to the view that they
are leaf-bases very similar to those on such fossil stems as Bucklandia
(Fittonia) Rigauxi (Sap.)[1369] and B. (Fittonia) squamata (Carr.)[1370]. One
partially carbonised scale yielded pieces of cuticle showing numerous
stomata similar to those of recent Cycads and the outlines of very thick-
walled epidermal cells[1371].
Eury-Cycadolepis Jenkinsiana (Tate).
The large and approximately orbicular or broadly ovate scales so named
are believed to be identical with Tate’s Cyclopteris Jenkinsiana[1372] from the
Uitenhage series of Cape Colony (Wealden). The scales reach a length of 12
cm. and were attached by a broad base; the lamina, which may be strongly
bent as though folded over some immature organ as a protective bract,
shows numerous repeatedly forked veins of the Cyclopteris type and several
anastomosing and irregular lines between the veins suggesting that the
scales were tomentose.
II. Reproductive Organs of Cycadean Plants other than
those of the Bennettitales.
The fact that practically all known Cycadean stems bore flowers either of
the Bennettites or Williamsonia type prepares us for the scarcity of
reproductive organs like those of recent Cycads. No specimens have been
discovered in a petrified state affording any evidence of their close affinity
to the cones, sporophylls, or seeds of the Cycadales. Such genera as
Cycadospadix, Androstrobus, and Zamiostrobus, as the following
descriptions show, are founded on material that is too imperfect to throw
much light on their true morphological nature. The probability is that some
at least of the specimens included in these genera are the reproductive
organs of Cycadean plants more closely allied to the existing Cycads than to
the Bennettitales. Among the numerous fossil seeds referred to such genera
as Cycadeospermum and Cycadinocarpus there are but few that can
confidently be assigned to the Cycadales rather than to the Ginkgoales or
Coniferales. While the seeds of the Bennettitales are clearly distinguished
by their much smaller size from those of modern Cycads, many of the latter
discovered in the Wealden beds of Sussex, some of which are attached to a
piece of stem[1368] in such a manner as to give support to the view that they
are leaf-bases very similar to those on such fossil stems as Bucklandia
(Fittonia) Rigauxi (Sap.)[1369] and B. (Fittonia) squamata (Carr.)[1370]. One
partially carbonised scale yielded pieces of cuticle showing numerous
stomata similar to those of recent Cycads and the outlines of very thick-
walled epidermal cells[1371].
Eury-Cycadolepis Jenkinsiana (Tate).
The large and approximately orbicular or broadly ovate scales so named
are believed to be identical with Tate’s Cyclopteris Jenkinsiana[1372] from the
Uitenhage series of Cape Colony (Wealden). The scales reach a length of 12
cm. and were attached by a broad base; the lamina, which may be strongly
bent as though folded over some immature organ as a protective bract,
shows numerous repeatedly forked veins of the Cyclopteris type and several
anastomosing and irregular lines between the veins suggesting that the
scales were tomentose.
II. Reproductive Organs of Cycadean Plants other than
those of the Bennettitales.
The fact that practically all known Cycadean stems bore flowers either of
the Bennettites or Williamsonia type prepares us for the scarcity of
reproductive organs like those of recent Cycads. No specimens have been
discovered in a petrified state affording any evidence of their close affinity
to the cones, sporophylls, or seeds of the Cycadales. Such genera as
Cycadospadix, Androstrobus, and Zamiostrobus, as the following
descriptions show, are founded on material that is too imperfect to throw
much light on their true morphological nature. The probability is that some
at least of the specimens included in these genera are the reproductive
organs of Cycadean plants more closely allied to the existing Cycads than to
the Bennettitales. Among the numerous fossil seeds referred to such genera
as Cycadeospermum and Cycadinocarpus there are but few that can
confidently be assigned to the Cycadales rather than to the Ginkgoales or
Coniferales. While the seeds of the Bennettitales are clearly distinguished
by their much smaller size from those of modern Cycads, many of the latter
Page 545
agree in size and form with those of some other Gymnosperms and in the
absence of anatomical details could not easily be identified as fossils. Some
of the examples included in the miscellaneous collection described by
authors as species of Carpolithus or Carpolithes agree closely in external
features with the seeds of modern Cycads, but it is seldom possible to
accept them as undoubted records of Cycadalean plants.
The general conclusion is that such meagre evidence as we possess
affords strong confirmation of the conclusion based on stems and foliage
from Jurassic and Cretaceous strata, namely that the present representatives
of the Cycadophyta are a relatively late product of evolution, though
retaining in their anatomical features many survivals from a remote
antiquity. The occurrence of Cycadean characteristics in the vegetative
organs of the Medulloseae and the recurrence of what may be called the
Cycadean seed-plan, with certain more or less striking peculiarities
reminiscent of earlier stages of evolution, in several types of Palaeozoic
seeds such as Cycadinocarpus, Stephanospermum, Lagenostoma and others
bear testimony to the antiquity of the Cycadean stock.
CARPOLITHUS[1373]. Linnaeus.
This generic name, as Nathorst[1374] has recently pointed out, was used by
Linnaeus in 1768 for ‘Phytolithus fructus’ and has therefore priority over
Sternberg’s genus Carpolites employed in 1825. Lester Ward[1375] attributes
Carpolithus to Stokes and Webb (1824) and states that in the plural form
the name was used by Walch in 1771. Carpolithus is a convenient term to
apply to fossil seeds that cannot be assigned to a particular group of plants
and which do not exhibit any peculiarities of form sufficiently striking to
deserve generic recognition. Pomel[1376] proposed the genus Ulospermum
but it never came into general use. Schimper’s genus Cycadinocarpus and
Saporta’s Cycadeospermum (preferable in its morphological implication),
though useful in the case of detached seeds of undoubted Cycadean affinity,
can seldom be employed without an admission that they may imply a
relationship that cannot be absolutely established. In the great majority of
cases the better plan is to be content with the more non-committal term
Carpolithus with the addition of a family-name when there are reasonably
good grounds for a more definite reference. No useful purpose would be
served by attempting a complete survey of the numerous casts and
impressions of supposed Cycadean seeds recorded in palaeobotanical
absence of anatomical details could not easily be identified as fossils. Some
of the examples included in the miscellaneous collection described by
authors as species of Carpolithus or Carpolithes agree closely in external
features with the seeds of modern Cycads, but it is seldom possible to
accept them as undoubted records of Cycadalean plants.
The general conclusion is that such meagre evidence as we possess
affords strong confirmation of the conclusion based on stems and foliage
from Jurassic and Cretaceous strata, namely that the present representatives
of the Cycadophyta are a relatively late product of evolution, though
retaining in their anatomical features many survivals from a remote
antiquity. The occurrence of Cycadean characteristics in the vegetative
organs of the Medulloseae and the recurrence of what may be called the
Cycadean seed-plan, with certain more or less striking peculiarities
reminiscent of earlier stages of evolution, in several types of Palaeozoic
seeds such as Cycadinocarpus, Stephanospermum, Lagenostoma and others
bear testimony to the antiquity of the Cycadean stock.
CARPOLITHUS[1373]. Linnaeus.
This generic name, as Nathorst[1374] has recently pointed out, was used by
Linnaeus in 1768 for ‘Phytolithus fructus’ and has therefore priority over
Sternberg’s genus Carpolites employed in 1825. Lester Ward[1375] attributes
Carpolithus to Stokes and Webb (1824) and states that in the plural form
the name was used by Walch in 1771. Carpolithus is a convenient term to
apply to fossil seeds that cannot be assigned to a particular group of plants
and which do not exhibit any peculiarities of form sufficiently striking to
deserve generic recognition. Pomel[1376] proposed the genus Ulospermum
but it never came into general use. Schimper’s genus Cycadinocarpus and
Saporta’s Cycadeospermum (preferable in its morphological implication),
though useful in the case of detached seeds of undoubted Cycadean affinity,
can seldom be employed without an admission that they may imply a
relationship that cannot be absolutely established. In the great majority of
cases the better plan is to be content with the more non-committal term
Carpolithus with the addition of a family-name when there are reasonably
good grounds for a more definite reference. No useful purpose would be
served by attempting a complete survey of the numerous casts and
impressions of supposed Cycadean seeds recorded in palaeobotanical
Page 546
literature, but a few types are briefly described as examples of specimens
with fairly well defined characters, which are in all probability Cycadean.
Fig. 585.
Carpolithus
conicus. From a
specimen in the
Fig. 584. Carpolithus conicus. The Malton Museum;
type-specimens in the Manchester nat. size.
Museum; nat. size. (a, No. 361; b,
c, No. 360.)
Carpolithus conicus (Cycadales?) Lindley and Hutton.
The original specimen figured by Lindley and Hutton[1377] from the
Coralline Oolite of Malton, Yorkshire, as Carpolithes conica and now in the
Manchester Museum, is represented in fig. 584. A second ‘species,’
Carpolithus Bucklandi Lind. and Hutt. ex Will. ms.[1378], from the same
locality is no doubt specifically identical with C. conicus. The seeds are
conical, broadly truncate at one end, presumably the base, and tapered to a
blunt apex; the broad end is characterised by the presence of three ridges or
in some specimens by a single median ridge illustrating an oscillation
between the radiospermic and platyspermic form similar to that in Ginkgo
biloba. As usually obtained the seeds are probably nucules or casts showing
the surface-features of the inner wall of the sclerotesta, the sarcotesta
with fairly well defined characters, which are in all probability Cycadean.
Fig. 585.
Carpolithus
conicus. From a
specimen in the
Fig. 584. Carpolithus conicus. The Malton Museum;
type-specimens in the Manchester nat. size.
Museum; nat. size. (a, No. 361; b,
c, No. 360.)
Carpolithus conicus (Cycadales?) Lindley and Hutton.
The original specimen figured by Lindley and Hutton[1377] from the
Coralline Oolite of Malton, Yorkshire, as Carpolithes conica and now in the
Manchester Museum, is represented in fig. 584. A second ‘species,’
Carpolithus Bucklandi Lind. and Hutt. ex Will. ms.[1378], from the same
locality is no doubt specifically identical with C. conicus. The seeds are
conical, broadly truncate at one end, presumably the base, and tapered to a
blunt apex; the broad end is characterised by the presence of three ridges or
in some specimens by a single median ridge illustrating an oscillation
between the radiospermic and platyspermic form similar to that in Ginkgo
biloba. As usually obtained the seeds are probably nucules or casts showing
the surface-features of the inner wall of the sclerotesta, the sarcotesta
Page 547
having been destroyed before fossilisation: the irregular marginal teeth at
the truncate end suggest casts of vascular bundles in the integument. The
scattered tubercles on the sides of some of the seeds (fig. 584, a) are
probably casts of holes in the shell bored by insects and comparable with
those occasionally preserved on the casts of Trigonocarpus. A specimen in
the Malton Museum shown in fig. 585 which may be an example of this
species illustrates the occurrence of an internal cast enclosed by the remains
of a thick testa. These Jurassic casts resemble the seeds of Macrozamia
Fraseri, but it is impossible to determine their systematic position with
confidence.
Carpolithus sp. (Cycadales?) Seward.
An unusually well preserved specimen from the Wealden beds of the
Sussex coast described under this name in 1895[1379] consists of a kernel and
mould, 1·8 × 1·1 cm. The mould from which the kernel is readily removed
is lined with a thin structure representing part of the testa and between this
and the surrounding rock is a layer of coal. On the surface of the kernel,
probably the cast of the seed-cavity, a reticulum of narrow grooves indicates
the course of the vascular bundles over the surface of the nucellus.
Carpolithus (Cycadales?) Pomelii (Saporta).
The specimen from the Upper Corallian of Châteauroux (Indre) on which
this species was founded by Saporta[1380] under the name Cycadeospermum
Pomelii is a large ovate cast, 5·5 cm. long and 3·5 cm. broad, closely
resembling some of the larger recent Cycadean seeds: it cannot be accepted
as a true record of the group without reservation.
Saporta describes other species of Cycadeospermum but none of them are
of any real importance from a botanical point of view: the same remark
applies to the seeds referred by Fontaine[1381] from Potomac beds to the
same genus, also to many other recorded examples of seeds that afford no
decisive evidence of affinity.
Some specimens described by Compter[1382] from the Lettenkohle of
Apolda (Thuringia) as Cycadean fruits—too imperfect to be determined
with accuracy—furnish an additional illustration of the slender foundation
the truncate end suggest casts of vascular bundles in the integument. The
scattered tubercles on the sides of some of the seeds (fig. 584, a) are
probably casts of holes in the shell bored by insects and comparable with
those occasionally preserved on the casts of Trigonocarpus. A specimen in
the Malton Museum shown in fig. 585 which may be an example of this
species illustrates the occurrence of an internal cast enclosed by the remains
of a thick testa. These Jurassic casts resemble the seeds of Macrozamia
Fraseri, but it is impossible to determine their systematic position with
confidence.
Carpolithus sp. (Cycadales?) Seward.
An unusually well preserved specimen from the Wealden beds of the
Sussex coast described under this name in 1895[1379] consists of a kernel and
mould, 1·8 × 1·1 cm. The mould from which the kernel is readily removed
is lined with a thin structure representing part of the testa and between this
and the surrounding rock is a layer of coal. On the surface of the kernel,
probably the cast of the seed-cavity, a reticulum of narrow grooves indicates
the course of the vascular bundles over the surface of the nucellus.
Carpolithus (Cycadales?) Pomelii (Saporta).
The specimen from the Upper Corallian of Châteauroux (Indre) on which
this species was founded by Saporta[1380] under the name Cycadeospermum
Pomelii is a large ovate cast, 5·5 cm. long and 3·5 cm. broad, closely
resembling some of the larger recent Cycadean seeds: it cannot be accepted
as a true record of the group without reservation.
Saporta describes other species of Cycadeospermum but none of them are
of any real importance from a botanical point of view: the same remark
applies to the seeds referred by Fontaine[1381] from Potomac beds to the
same genus, also to many other recorded examples of seeds that afford no
decisive evidence of affinity.
Some specimens described by Compter[1382] from the Lettenkohle of
Apolda (Thuringia) as Cycadean fruits—too imperfect to be determined
with accuracy—furnish an additional illustration of the slender foundation
Page 548
on which many of the records of supposed Cycadean reproductive organs
are based.
CYCADOSPADIX. Schimper.
This name was proposed by Schimper[1383] for some French Jurassic
fossils, described by Pomel[1384] as Crossozamia Hennocquei and C.
Moraeana, on the ground that they bear a close resemblance to the
megasporophylls of Cycas. Their occasional association with Otozamites
fronds suggested a reference to the same parent-plant, but such data as we
have point to Otozamites fronds having been borne by plants with the
Williamsonia type of flower. Schenk[1385], who figured a specimen of
Cycadospadix from France as the inflorescence of a Cycad, expresses the
more probable opinion that it belonged to a plant with Cycadites fronds. A
Permian species described by Renault as Cycadospadix Milleryensis is now
transferred to the genus Strobilites[1386].
Cycadospadix Pasinianus Zigno.
This species, first described from Jurassic strata in Northern Italy[1387], is
recorded also from the Kimmeridgian of France[1388] and Scotland[1389].
Zigno’s figures give a fairly accurate representation of the type-specimens
in the Padua Museum. The megasporophylls, almost identical in shape with
those of some recent species of Cycas (figs. 381; 392, A–C), consist of a
broadly lanceolate or triangular limb with deeply laciniate sides terminating
a pedicel, or the distal expansion may be preserved without the stalk from
which it was no doubt easily detached as in certain recent Cycads (cf. fig.
392, A). In the specimen from Scotland there are no clear indications of
veins in the lamina, which may have been woolly as in Cycas. In some of
the specimens figured by Saporta[1390] and now in the École des Mines,
Paris, the stalk is absent, but in pedicellate examples scars occur on the
sides of the narrow axis and casts of seeds are found in the same beds. A
good example of Cycadospadix Hennocquei is figured by Saporta from a
drawing supplied by Schimper showing two seed-scars near the base of the
lamina: the same specimen, as figured by Saporta and Marion[1391], bears a
seed, but this is presumably a partial restoration. The occurrence of
Cycadites rectangularis Brauns at Hettange in association with
Cycadospadix strengthens the conclusion, based on the form of the
are based.
CYCADOSPADIX. Schimper.
This name was proposed by Schimper[1383] for some French Jurassic
fossils, described by Pomel[1384] as Crossozamia Hennocquei and C.
Moraeana, on the ground that they bear a close resemblance to the
megasporophylls of Cycas. Their occasional association with Otozamites
fronds suggested a reference to the same parent-plant, but such data as we
have point to Otozamites fronds having been borne by plants with the
Williamsonia type of flower. Schenk[1385], who figured a specimen of
Cycadospadix from France as the inflorescence of a Cycad, expresses the
more probable opinion that it belonged to a plant with Cycadites fronds. A
Permian species described by Renault as Cycadospadix Milleryensis is now
transferred to the genus Strobilites[1386].
Cycadospadix Pasinianus Zigno.
This species, first described from Jurassic strata in Northern Italy[1387], is
recorded also from the Kimmeridgian of France[1388] and Scotland[1389].
Zigno’s figures give a fairly accurate representation of the type-specimens
in the Padua Museum. The megasporophylls, almost identical in shape with
those of some recent species of Cycas (figs. 381; 392, A–C), consist of a
broadly lanceolate or triangular limb with deeply laciniate sides terminating
a pedicel, or the distal expansion may be preserved without the stalk from
which it was no doubt easily detached as in certain recent Cycads (cf. fig.
392, A). In the specimen from Scotland there are no clear indications of
veins in the lamina, which may have been woolly as in Cycas. In some of
the specimens figured by Saporta[1390] and now in the École des Mines,
Paris, the stalk is absent, but in pedicellate examples scars occur on the
sides of the narrow axis and casts of seeds are found in the same beds. A
good example of Cycadospadix Hennocquei is figured by Saporta from a
drawing supplied by Schimper showing two seed-scars near the base of the
lamina: the same specimen, as figured by Saporta and Marion[1391], bears a
seed, but this is presumably a partial restoration. The occurrence of
Cycadites rectangularis Brauns at Hettange in association with
Cycadospadix strengthens the conclusion, based on the form of the
Page 549
megasporophylls, that some of the Jurassic Cycads bore megasporophylls
very similar to those of existing species of Cycas.
Cycadospadix integer Nathorst.
This Rhaetic species from the south of Sweden[1392] was instituted for an
imperfect broadly lanceolate lamina recalling the distal end of the
megasporophyll of a Cycas: the discovery of a more complete example[1393]
justifies Nathorst’s use of the name Cycadospadix, though without further
evidence one hesitates to regard the species as a thoroughly trustworthy
record of a Cycadean fertile leaf. The species is characterised by the entire
margin of the broad and relatively short and thick terminal limb borne on a
broad stalk with alternate lateral projections presumably marking the
position of the seeds.
These species of Cycadospadix are particularly interesting as evidence—
though not amounting to demonstration—of the production by some
Jurassic and Rhaetic plants of fertile leaves agreeing closely with those of
Cycas. It would seem from the abundance of Bennettitalean flowers and the
very scanty remains of fertile leaves or cones like those of modern Cycads
that the existing type was exceptional in Mesozoic floras.
BEANIA. Carruthers.
Beania gracilis Carruthers.
The generic name Beania[1394] was given to a branched fertile shoot (fig.
586) from the Middle Jurassic beds at Gristhorpe, Yorkshire, characterised
by loosely disposed sporophylls bearing two sessile seeds: each sporophyll
is given off at a wide angle from a fairly stout axis and the seeds are borne
on the adaxial side of a peltate distal expansion. Carruthers compared the
type-species with a cone of Zamia with which it agrees in the general plan
of construction but differs in the more open habit and in the longer and
more slender seed-bearing pedicels. The same type of shoot was figured by
Lindley and Hutton[1395] as Sphaereda paradoxa. Beania is generally
regarded as a Cycadean reproductive shoot, but there is no doubt that the
majority of Jurassic Cycadophyta possessed flowers of the Bennettites
types, and it is clear that Beania differs considerably from Bennettites and
Williamsonia. Another suggestion is that Beania may belong to some
very similar to those of existing species of Cycas.
Cycadospadix integer Nathorst.
This Rhaetic species from the south of Sweden[1392] was instituted for an
imperfect broadly lanceolate lamina recalling the distal end of the
megasporophyll of a Cycas: the discovery of a more complete example[1393]
justifies Nathorst’s use of the name Cycadospadix, though without further
evidence one hesitates to regard the species as a thoroughly trustworthy
record of a Cycadean fertile leaf. The species is characterised by the entire
margin of the broad and relatively short and thick terminal limb borne on a
broad stalk with alternate lateral projections presumably marking the
position of the seeds.
These species of Cycadospadix are particularly interesting as evidence—
though not amounting to demonstration—of the production by some
Jurassic and Rhaetic plants of fertile leaves agreeing closely with those of
Cycas. It would seem from the abundance of Bennettitalean flowers and the
very scanty remains of fertile leaves or cones like those of modern Cycads
that the existing type was exceptional in Mesozoic floras.
BEANIA. Carruthers.
Beania gracilis Carruthers.
The generic name Beania[1394] was given to a branched fertile shoot (fig.
586) from the Middle Jurassic beds at Gristhorpe, Yorkshire, characterised
by loosely disposed sporophylls bearing two sessile seeds: each sporophyll
is given off at a wide angle from a fairly stout axis and the seeds are borne
on the adaxial side of a peltate distal expansion. Carruthers compared the
type-species with a cone of Zamia with which it agrees in the general plan
of construction but differs in the more open habit and in the longer and
more slender seed-bearing pedicels. The same type of shoot was figured by
Lindley and Hutton[1395] as Sphaereda paradoxa. Beania is generally
regarded as a Cycadean reproductive shoot, but there is no doubt that the
majority of Jurassic Cycadophyta possessed flowers of the Bennettites
types, and it is clear that Beania differs considerably from Bennettites and
Williamsonia. Another suggestion is that Beania may belong to some
Page 550
member of the Ginkgoales[1396]: though very different
from the normal ovuliferous shoot of a Ginkgo, it
resembles some abnormal forms (e.g. fig. 631, D) in
which the ovules occur on elongated pedicels, but
they are borne singly and the micropyle is directed
outwards, while in Beania the ovules are attached in
pairs to the inner face of a distal expansion. There is
no conclusive evidence in support of either
interpretation, though the general agreement between
the Jurassic type and the cones of recent Cycads
would seem to favour the inclusion of Beania among
the Cycadophyta. Fig. 586. Beania
A specimen described by Nathorst[1397] from Upper gracilis. (After
Jurassic rocks in the North of Scotland as Beania Carruthers; ½
Carruthersi closely resembles the type-species, nat. size.)
differing chiefly in its smaller size and in the rather closer arrangement of
the sporophylls. The seed-like bodies borne in pairs on the adaxial side of
the terminally expanded pedicels are covered with small granulations which
Nathorst thinks may be clusters of microspores, the apparent seeds being
‘antherangia.’ The granulations are, however, very similar to those on the
larger detached seed-like bodies originally described by Nathorst from
Rhaetic beds in Sweden as Antherangiopsis rediviva[1398]: subsequent
examination of that species demonstrated that the granulations are due to
the presence of resinous bodies in the tissues of true seeds[1399], and it is not
improbable that a similar interpretation may hold for the surface-features in
the supposed male organs of Beania Carruthersi. Pending further evidence
it may be suggested that Beania Carruthersi is like B. gracilis a seed-
bearing shoot. The Rhaetic specimens described by Nathorst as
Stenorrachis scanicus[1400] are similar in habit to Beania but differ in the
forking of the sporophylls (fig. 656) and in the absence of any terminal
swelling on which the seeds are borne: Nathorst considers that Stenorrachis
may be the female organ of a Nilssonia and it is not improbable that that
genus and Beania are closely allied types. We have no definite information
with regard to the reproductive organs of the Nilssoniales: the closer
resemblance which their fronds bear in the structure of the epidermal cells
to those of recent Cycads is consistent with the view that their fertile shoots
were also more like those of existing types. It is, however, still an unsettled
from the normal ovuliferous shoot of a Ginkgo, it
resembles some abnormal forms (e.g. fig. 631, D) in
which the ovules occur on elongated pedicels, but
they are borne singly and the micropyle is directed
outwards, while in Beania the ovules are attached in
pairs to the inner face of a distal expansion. There is
no conclusive evidence in support of either
interpretation, though the general agreement between
the Jurassic type and the cones of recent Cycads
would seem to favour the inclusion of Beania among
the Cycadophyta. Fig. 586. Beania
A specimen described by Nathorst[1397] from Upper gracilis. (After
Jurassic rocks in the North of Scotland as Beania Carruthers; ½
Carruthersi closely resembles the type-species, nat. size.)
differing chiefly in its smaller size and in the rather closer arrangement of
the sporophylls. The seed-like bodies borne in pairs on the adaxial side of
the terminally expanded pedicels are covered with small granulations which
Nathorst thinks may be clusters of microspores, the apparent seeds being
‘antherangia.’ The granulations are, however, very similar to those on the
larger detached seed-like bodies originally described by Nathorst from
Rhaetic beds in Sweden as Antherangiopsis rediviva[1398]: subsequent
examination of that species demonstrated that the granulations are due to
the presence of resinous bodies in the tissues of true seeds[1399], and it is not
improbable that a similar interpretation may hold for the surface-features in
the supposed male organs of Beania Carruthersi. Pending further evidence
it may be suggested that Beania Carruthersi is like B. gracilis a seed-
bearing shoot. The Rhaetic specimens described by Nathorst as
Stenorrachis scanicus[1400] are similar in habit to Beania but differ in the
forking of the sporophylls (fig. 656) and in the absence of any terminal
swelling on which the seeds are borne: Nathorst considers that Stenorrachis
may be the female organ of a Nilssonia and it is not improbable that that
genus and Beania are closely allied types. We have no definite information
with regard to the reproductive organs of the Nilssoniales: the closer
resemblance which their fronds bear in the structure of the epidermal cells
to those of recent Cycads is consistent with the view that their fertile shoots
were also more like those of existing types. It is, however, still an unsettled
Page 551
point whether Beania is more closely allied to the Cycadophyta or to the
Ginkgoales, but the balance of opinion is in favour of the former alliance.
Zamiostrobus. Endlicher.
Cycadeostrobus. Carruthers.
Though instituted by Endlicher[1401] for a cone figured by Lindley and
Hutton as Zamia macrocephala[1402] which is almost certainly Abietineous
and has no claim to be included in the Cycadales, the genus Zamiostrobus
has been adopted by many authors for Cycadean ovulate cones, not only
such as are believed to be closely allied to those of Zamia but for Cycadean
cones generally. Carruthers[1403] suggested Cycadeostrobus as a more
suitable name on the ground that it is less limited in its implication of
affinity; but, as Fliche points out, Endlicher’s generic name has been widely
adopted in a comprehensive sense as standing for Cycadean megastrobili,
excluding the supposed Cycas-like megasporophylls, included under
Cycadospadix.
Many of the specimens described as species of Zamiostrobus are of little
or no value as records of Cycadean plants, e.g. Zamiostrobus orientalis
Heer[1404] from the Jurassic beds of Amurland. A Lower Cretaceous (Albian)
species described by Fliche[1405] as Zamiostrobus Loppineti, though not
entirely satisfactory, is more likely to belong to the Cycadales. The type-
specimen is an elliptical strobilus, 5·5 cm. × 3·2 cm., consisting of an axis
bearing at right-angles numerous small, contiguous, peltate
megasporophylls each with two small seeds on the lower surface. The
figures given by Fliche are, however, not convincing. An examination of
specimens in the British Museum, from Wealden and Jurassic rocks,
described by Carruthers as species of Cycadeostrobus, convinced me that
several are undoubtedly Araucarian cones[1406]. Solms-Laubach[1407] called
attention to the Araucarian appearance of Cycadeostrobus Brunonis, a cone
from an unknown locality, and this with other species, e.g. C. elegans, C.
sphaericus, C. truncatus, etc., may safely be referred to Araucarites. The
specimen figured by Lindley and Hutton[1408] as Zamia crassa from the
Inferior Oolite of Towcester (Northamptonshire) affords no satisfactory
evidence of Cycadean affinity. The Lower Cretaceous Bohemian specimens
described by Corda[1409] and Velenovský[1410] as Microzamia gibba should
not be included in a genus implying Cycadean affinity: though Velenovský
Ginkgoales, but the balance of opinion is in favour of the former alliance.
Zamiostrobus. Endlicher.
Cycadeostrobus. Carruthers.
Though instituted by Endlicher[1401] for a cone figured by Lindley and
Hutton as Zamia macrocephala[1402] which is almost certainly Abietineous
and has no claim to be included in the Cycadales, the genus Zamiostrobus
has been adopted by many authors for Cycadean ovulate cones, not only
such as are believed to be closely allied to those of Zamia but for Cycadean
cones generally. Carruthers[1403] suggested Cycadeostrobus as a more
suitable name on the ground that it is less limited in its implication of
affinity; but, as Fliche points out, Endlicher’s generic name has been widely
adopted in a comprehensive sense as standing for Cycadean megastrobili,
excluding the supposed Cycas-like megasporophylls, included under
Cycadospadix.
Many of the specimens described as species of Zamiostrobus are of little
or no value as records of Cycadean plants, e.g. Zamiostrobus orientalis
Heer[1404] from the Jurassic beds of Amurland. A Lower Cretaceous (Albian)
species described by Fliche[1405] as Zamiostrobus Loppineti, though not
entirely satisfactory, is more likely to belong to the Cycadales. The type-
specimen is an elliptical strobilus, 5·5 cm. × 3·2 cm., consisting of an axis
bearing at right-angles numerous small, contiguous, peltate
megasporophylls each with two small seeds on the lower surface. The
figures given by Fliche are, however, not convincing. An examination of
specimens in the British Museum, from Wealden and Jurassic rocks,
described by Carruthers as species of Cycadeostrobus, convinced me that
several are undoubtedly Araucarian cones[1406]. Solms-Laubach[1407] called
attention to the Araucarian appearance of Cycadeostrobus Brunonis, a cone
from an unknown locality, and this with other species, e.g. C. elegans, C.
sphaericus, C. truncatus, etc., may safely be referred to Araucarites. The
specimen figured by Lindley and Hutton[1408] as Zamia crassa from the
Inferior Oolite of Towcester (Northamptonshire) affords no satisfactory
evidence of Cycadean affinity. The Lower Cretaceous Bohemian specimens
described by Corda[1409] and Velenovský[1410] as Microzamia gibba should
not be included in a genus implying Cycadean affinity: though Velenovský
Page 552
states that the megasporophylls bear a pair of seeds his illustrations do not
afford any satisfactory evidence of this Cycadean character. Similarly the
fossil regarded by Carruthers[1411] as probably a male flower of Bucklandia
is almost certainly an Araucarian cone. A small cone from the Lower
Miocene of Armissan (Aude) named by Schimper Zamiostrobus Saportana
and figured by Saporta and Marion[1412] may, as Solms-Laubach says, be
Cycadean, but we have no information with regard to the internal structure
or as to the presence or position of the seeds.
Androstrobus. Schimper.
Schimper[1413] instituted this genus for ‘amenta, cycadeacea antherifera,
cylindrica, e squamis imbricatis, latere postico antheras sessiles ferentibus
efformata.’ It may conveniently be applied to fossils which resemble the
male cones of recent Cycads sufficiently to justify the use of a name
implying relationship. As so defined, Androstrobus is used in a more
restricted sense than the word suggests, just as Masculostrobus[1414] has been
employed for fossils that are believed to be the corresponding organs of
Conifers. Among the few species assigned to Schimper’s genus reference
may be made to A. Balduini Sap., originally named by Schimper A.
zamioides, from the Upper Bathonian of Etrochy, and A. Guerangeri
(Brongn.), another French type[1415]. Heer’s species A. sibirica[1416] of
Jurassic age is represented by a slender axis bearing numerous appendages
which in surface-view have the form of polygonal discs: there are no
indications of microsporangia and the evidence of Cycadean affinity is far
from convincing. Nathorst’s Rhaetic species A. borealis[1417] is no more
satisfactory as a record of a Cycadean strobilus. A fossil from the Lower
Cretaceous of Bohemia described as Zamites familiaris and regarded by
Corda[1418] and Carruthers[1419] as a male flower of a Cycad though not above
suspicion may be included in Androstrobus.
Under the name Fričia nobilis Velenovský[1420] described some cones
from the Lower Cretaceous plant-beds of Bohemia which he regards as
male strobili of some Cycadean plant: the cone, as shown in Velenovský’s
restoration, is 10 cm. long and 5 cm. in diameter; it bears a close superficial
resemblance to a large cone of Zamia and consists of a stout axis bearing
contiguous peltate, hexagonal, scales gradually contracted towards the
proximal end, similar to those of Androstrobus. The evidence on which this
afford any satisfactory evidence of this Cycadean character. Similarly the
fossil regarded by Carruthers[1411] as probably a male flower of Bucklandia
is almost certainly an Araucarian cone. A small cone from the Lower
Miocene of Armissan (Aude) named by Schimper Zamiostrobus Saportana
and figured by Saporta and Marion[1412] may, as Solms-Laubach says, be
Cycadean, but we have no information with regard to the internal structure
or as to the presence or position of the seeds.
Androstrobus. Schimper.
Schimper[1413] instituted this genus for ‘amenta, cycadeacea antherifera,
cylindrica, e squamis imbricatis, latere postico antheras sessiles ferentibus
efformata.’ It may conveniently be applied to fossils which resemble the
male cones of recent Cycads sufficiently to justify the use of a name
implying relationship. As so defined, Androstrobus is used in a more
restricted sense than the word suggests, just as Masculostrobus[1414] has been
employed for fossils that are believed to be the corresponding organs of
Conifers. Among the few species assigned to Schimper’s genus reference
may be made to A. Balduini Sap., originally named by Schimper A.
zamioides, from the Upper Bathonian of Etrochy, and A. Guerangeri
(Brongn.), another French type[1415]. Heer’s species A. sibirica[1416] of
Jurassic age is represented by a slender axis bearing numerous appendages
which in surface-view have the form of polygonal discs: there are no
indications of microsporangia and the evidence of Cycadean affinity is far
from convincing. Nathorst’s Rhaetic species A. borealis[1417] is no more
satisfactory as a record of a Cycadean strobilus. A fossil from the Lower
Cretaceous of Bohemia described as Zamites familiaris and regarded by
Corda[1418] and Carruthers[1419] as a male flower of a Cycad though not above
suspicion may be included in Androstrobus.
Under the name Fričia nobilis Velenovský[1420] described some cones
from the Lower Cretaceous plant-beds of Bohemia which he regards as
male strobili of some Cycadean plant: the cone, as shown in Velenovský’s
restoration, is 10 cm. long and 5 cm. in diameter; it bears a close superficial
resemblance to a large cone of Zamia and consists of a stout axis bearing
contiguous peltate, hexagonal, scales gradually contracted towards the
proximal end, similar to those of Androstrobus. The evidence on which this
Page 553
species is identified as a male cone rests on the occurrence of numerous pits
on the surface of the scales; but no spores or sporangia were found and the
pits as shown in the published figures do not present the appearance of scars
of sporangia.
The Rhaetic specimen originally named by Nathorst Androstrobus Scotti
and afterwards transferred to the genus Lycostrobus was described in
Volume ii.[1421]
Androstrobus Nathorsti Seward.
The type-specimens were obtained from the Wealden beds of Sussex:
they were referred to the genus Androstrobus on evidence which cannot be
regarded as decisive[1422]. A fairly stout axis, 6·5 cm. long, bearing spirally
disposed sub-triangular scales hexagonal in section and attached to the axis
by a broad base; the scales, or sporophylls, are 1–1·5 cm. long and
gradually tapered towards a pointed or slightly rounded apex. Near the
proximal end of some of the sporophylls there are regularly arranged
polygonal depressions which may be impressions of microsporangia. The
regular disposition of the depressions is a striking feature and in contrast to
the less regular reticulum exposed after the removal of the sporangia from
the microsporophyll of a recent Cycad. An examination of the cuticular
membrane of the microsporophylls shows that the epidermal cells have
thick and straight walls[1423], characters consistent with the supposed
Cycadean affinity of the strobilus.
on the surface of the scales; but no spores or sporangia were found and the
pits as shown in the published figures do not present the appearance of scars
of sporangia.
The Rhaetic specimen originally named by Nathorst Androstrobus Scotti
and afterwards transferred to the genus Lycostrobus was described in
Volume ii.[1421]
Androstrobus Nathorsti Seward.
The type-specimens were obtained from the Wealden beds of Sussex:
they were referred to the genus Androstrobus on evidence which cannot be
regarded as decisive[1422]. A fairly stout axis, 6·5 cm. long, bearing spirally
disposed sub-triangular scales hexagonal in section and attached to the axis
by a broad base; the scales, or sporophylls, are 1–1·5 cm. long and
gradually tapered towards a pointed or slightly rounded apex. Near the
proximal end of some of the sporophylls there are regularly arranged
polygonal depressions which may be impressions of microsporangia. The
regular disposition of the depressions is a striking feature and in contrast to
the less regular reticulum exposed after the removal of the sporangia from
the microsporophyll of a recent Cycad. An examination of the cuticular
membrane of the microsporophylls shows that the epidermal cells have
thick and straight walls[1423], characters consistent with the supposed
Cycadean affinity of the strobilus.
Page 554
Page 555
CHAPTER XXXIX.
CYCADOPHYTAN FRONDS.
Occasional reference is made to Cycadean fronds in the account of
flowers and stems but it is seldom that genera or species founded on leaves
can be definitely correlated with particular types of reproductive organs or
stems. As in the case of Ferns and Pteridosperms so also with detached
leaves believed to be Cycadean, a large number of generic names have been
employed for impressions which afford no information with regard to
anatomical characters except, in some of the more favourably preserved
specimens, a few facts as to the epidermal cells. Though association often
suggests original connexion it is inadvisable except in well established
cases to extend to fronds generic terms based on reproductive shoots. The
designation Zamites has long been used for fronds that are clearly not
closely related to recent species of Zamia, and were it not an old established
genus the significance of which is not likely to be misunderstood, it would
be wiser to substitute for it some name implying no affinity with any
existing type. On the other hand the employment by some authors of such
generic names as Encephalartos and Ceratozamia is not warranted by the
evidence furnished by the imperfect material. Prof. Newberry[1424] described
as Encephalartos? denticulatus a piece of a frond from Rhaetic beds in
Honduras characterised by lanceolate pinnae (30 × 6 mm.) gradually
narrowed towards the acute apex and abruptly contracted at the base: the
method of attachment of the pinnae appears to agree with that in the genus
Zamites. In this case there is no valid reason for assuming a relationship
with Encephalartos or with any recent type. An impression from Lower
Cretaceous, Dakota, beds in Kansas described as Encephalartos cretaceus
Knowlt. ex Lesq. ms.[1425] consists of a piece of lamina, 9 × 4 cm., obovate-
oblong and with a cuneate base, a serrate margin and thick diverging veins:
the specimen is too incomplete to serve as a record of any Cycadean genus.
The generic name Encephalartopsis was applied by Fontaine[1426] to some
imperfect pinnae from the Potomac beds characterised by a linear-elliptical
lamina with a spinous margin and slightly diverging and occasionally
anastomosing veins. The figured examples of the type-species, E. nervosa,
CYCADOPHYTAN FRONDS.
Occasional reference is made to Cycadean fronds in the account of
flowers and stems but it is seldom that genera or species founded on leaves
can be definitely correlated with particular types of reproductive organs or
stems. As in the case of Ferns and Pteridosperms so also with detached
leaves believed to be Cycadean, a large number of generic names have been
employed for impressions which afford no information with regard to
anatomical characters except, in some of the more favourably preserved
specimens, a few facts as to the epidermal cells. Though association often
suggests original connexion it is inadvisable except in well established
cases to extend to fronds generic terms based on reproductive shoots. The
designation Zamites has long been used for fronds that are clearly not
closely related to recent species of Zamia, and were it not an old established
genus the significance of which is not likely to be misunderstood, it would
be wiser to substitute for it some name implying no affinity with any
existing type. On the other hand the employment by some authors of such
generic names as Encephalartos and Ceratozamia is not warranted by the
evidence furnished by the imperfect material. Prof. Newberry[1424] described
as Encephalartos? denticulatus a piece of a frond from Rhaetic beds in
Honduras characterised by lanceolate pinnae (30 × 6 mm.) gradually
narrowed towards the acute apex and abruptly contracted at the base: the
method of attachment of the pinnae appears to agree with that in the genus
Zamites. In this case there is no valid reason for assuming a relationship
with Encephalartos or with any recent type. An impression from Lower
Cretaceous, Dakota, beds in Kansas described as Encephalartos cretaceus
Knowlt. ex Lesq. ms.[1425] consists of a piece of lamina, 9 × 4 cm., obovate-
oblong and with a cuneate base, a serrate margin and thick diverging veins:
the specimen is too incomplete to serve as a record of any Cycadean genus.
The generic name Encephalartopsis was applied by Fontaine[1426] to some
imperfect pinnae from the Potomac beds characterised by a linear-elliptical
lamina with a spinous margin and slightly diverging and occasionally
anastomosing veins. The figured examples of the type-species, E. nervosa,
Page 556
suggest pinnae like those of Ctenis; but in the absence of a rachis the
method of attachment of the segments cannot be ascertained. Saporta[1427]
named a specimen from the Miocene flora of Koumi, Greece,
Encephalartos Gorceixianus because of its resemblance in habit to some
species of the recent genus; but the designation Zamites would be more
appropriate. Ettingshausen recorded an imperfect impression of a pinna
from Tertiary rocks in Styria as Ceratozamia Hofmanni[1428] although it is by
no means certain that the fragment is even Cycadean. The genus
Taeniopteris was described in the second volume of this book as probably a
Pteridophyte, though of uncertain systematic position: it has, however, been
shown by Mr Thomas[1429] that the Jurassic species T. vittata was almost
certainly borne on a stem with reproductive organs constructed on the
Bennettitalean plan. Further research may enable us to fix the position of
other species but as yet T. vittata is the only representative of the genus
which there is good reason for assigning to the Bennettitales.
It is undoubtedly true that Cycadean plants, using the term in a wide
sense to include the Bennettitales as well as the Cycadales, bulked largely
in Upper Triassic, Rhaetic, Jurassic-Wealden floras; the Bennettitales
probably reached their maximum development as regards wealth of form
and geographical range in the latter part of the Jurassic period and in the
earliest phase of the Cretaceous epoch. In Triassic floras Cycadean plants
are represented almost solely by fronds but the very close resemblance
between Keuper species and forms that in Jurassic rocks are found in
association with fertile shoots leaves little doubt as to the affinity of Keuper
and Rhaetic species.
The evidence obtained from Permo-Carboniferous strata is much more
meagre, at least as regards Cycadean leaves: the occurrence of certain
morphological Cycadean features is revealed by petrified vegetative organs
of Palaeozoic plants, and the Cycadean plan of organisation is conspicuous
in many Carboniferous and Permian seeds. The discovery of frond-
impressions identical in external characters with Mesozoic genera may be
accepted as a substantial indication that genera already existed possessing
foliage of the Cycadean type, though we have no certain information with
regard to the nature of the other organs of the parent-plants. A few examples
of Palaeozoic species are included among those selected in illustration of
the different genera, namely Plagiozamites Planchardi, Sphenozamites
method of attachment of the segments cannot be ascertained. Saporta[1427]
named a specimen from the Miocene flora of Koumi, Greece,
Encephalartos Gorceixianus because of its resemblance in habit to some
species of the recent genus; but the designation Zamites would be more
appropriate. Ettingshausen recorded an imperfect impression of a pinna
from Tertiary rocks in Styria as Ceratozamia Hofmanni[1428] although it is by
no means certain that the fragment is even Cycadean. The genus
Taeniopteris was described in the second volume of this book as probably a
Pteridophyte, though of uncertain systematic position: it has, however, been
shown by Mr Thomas[1429] that the Jurassic species T. vittata was almost
certainly borne on a stem with reproductive organs constructed on the
Bennettitalean plan. Further research may enable us to fix the position of
other species but as yet T. vittata is the only representative of the genus
which there is good reason for assigning to the Bennettitales.
It is undoubtedly true that Cycadean plants, using the term in a wide
sense to include the Bennettitales as well as the Cycadales, bulked largely
in Upper Triassic, Rhaetic, Jurassic-Wealden floras; the Bennettitales
probably reached their maximum development as regards wealth of form
and geographical range in the latter part of the Jurassic period and in the
earliest phase of the Cretaceous epoch. In Triassic floras Cycadean plants
are represented almost solely by fronds but the very close resemblance
between Keuper species and forms that in Jurassic rocks are found in
association with fertile shoots leaves little doubt as to the affinity of Keuper
and Rhaetic species.
The evidence obtained from Permo-Carboniferous strata is much more
meagre, at least as regards Cycadean leaves: the occurrence of certain
morphological Cycadean features is revealed by petrified vegetative organs
of Palaeozoic plants, and the Cycadean plan of organisation is conspicuous
in many Carboniferous and Permian seeds. The discovery of frond-
impressions identical in external characters with Mesozoic genera may be
accepted as a substantial indication that genera already existed possessing
foliage of the Cycadean type, though we have no certain information with
regard to the nature of the other organs of the parent-plants. A few examples
of Palaeozoic species are included among those selected in illustration of
the different genera, namely Plagiozamites Planchardi, Sphenozamites
Page 557
Rochei, Pterophyllum Fayoli, P. Cambryi: among other recorded instances
of Palaeozoic species are Pterophyllum Cottaeanum Gutb.[1430], a Permian
type similar in habit to Ctenis but without anastomosing veins, a feature in
which it resembles Pseudoctenis; the Carboniferous species Pterophyllum
inflexum Eich.[1431] from the Altai mountains, transferred by Zeiller to
Dioonites; P. blechnoides Sand.[1432] from the Stephanian of Oppenau;
Pterophyllum Grand’Euryanum[1433] from Upper Carboniferous beds in
France, and P. gonorrachis Goepp.[1434] from Silesia. An examination of the
type-specimens of the Carboniferous species Cycadites gyrosus Goepp. and
C. taxodinus Goepp.[1435] in the Breslau Museum led me to regard the
material as too imperfect to determine.
A conclusion that is forced upon us by a consideration of the geological
range of Cycadean fronds is that at the close of the Wealden period, a period
very closely linked in the character of the vegetation with the preceding
Jurassic floras, there appears to have been a relatively sudden decrease in
the number of members of the Cycadophyta: the decline in the fortunes of
Cycadean plants is coincident with the rise and remarkably rapid extension
of the Angiosperms. From Middle and Upper Cretaceous and from Tertiary
beds very few Cycadean remains have been obtained and many of them are
represented by fragmentary fossils that afford no definite evidence of
affinity to recent genera. The antiquity of the Cycadales, that is the section
represented by existing Cycads, cannot be determined; but it would seem
probable that if the Cycads apart from the Bennettitales existed in Jurassic
and Lower Cretaceous floras they occupied a very subordinate position in
comparison with the extinct Bennettitales. There are no data pointing to any
widespread occurrence of the Cycadales in the Northern Hemisphere in
Tertiary times at all comparable with the geographical range of Tertiary
ancestors of the solitary survivor of the Ginkgoales.
The following records of Tertiary Cycadean fronds illustrate the paucity
of the records. Reference has already been made to Encephalartos
Gorceixianus Sap. of Miocene age, a species that has no claim to be
regarded as an example of the recent South African genus. The specimen
described by Saporta and Marion as ? Zamites palaeocenicus[1436] from the
Eocene of Gelinden is too imperfect to serve as a trustworthy record. A
more satisfactory species, similar in habit to Zamites gigas, is that on which
Saporta founded the species Zamites epibius[1437] from Lower Miocene beds
of Palaeozoic species are Pterophyllum Cottaeanum Gutb.[1430], a Permian
type similar in habit to Ctenis but without anastomosing veins, a feature in
which it resembles Pseudoctenis; the Carboniferous species Pterophyllum
inflexum Eich.[1431] from the Altai mountains, transferred by Zeiller to
Dioonites; P. blechnoides Sand.[1432] from the Stephanian of Oppenau;
Pterophyllum Grand’Euryanum[1433] from Upper Carboniferous beds in
France, and P. gonorrachis Goepp.[1434] from Silesia. An examination of the
type-specimens of the Carboniferous species Cycadites gyrosus Goepp. and
C. taxodinus Goepp.[1435] in the Breslau Museum led me to regard the
material as too imperfect to determine.
A conclusion that is forced upon us by a consideration of the geological
range of Cycadean fronds is that at the close of the Wealden period, a period
very closely linked in the character of the vegetation with the preceding
Jurassic floras, there appears to have been a relatively sudden decrease in
the number of members of the Cycadophyta: the decline in the fortunes of
Cycadean plants is coincident with the rise and remarkably rapid extension
of the Angiosperms. From Middle and Upper Cretaceous and from Tertiary
beds very few Cycadean remains have been obtained and many of them are
represented by fragmentary fossils that afford no definite evidence of
affinity to recent genera. The antiquity of the Cycadales, that is the section
represented by existing Cycads, cannot be determined; but it would seem
probable that if the Cycads apart from the Bennettitales existed in Jurassic
and Lower Cretaceous floras they occupied a very subordinate position in
comparison with the extinct Bennettitales. There are no data pointing to any
widespread occurrence of the Cycadales in the Northern Hemisphere in
Tertiary times at all comparable with the geographical range of Tertiary
ancestors of the solitary survivor of the Ginkgoales.
The following records of Tertiary Cycadean fronds illustrate the paucity
of the records. Reference has already been made to Encephalartos
Gorceixianus Sap. of Miocene age, a species that has no claim to be
regarded as an example of the recent South African genus. The specimen
described by Saporta and Marion as ? Zamites palaeocenicus[1436] from the
Eocene of Gelinden is too imperfect to serve as a trustworthy record. A
more satisfactory species, similar in habit to Zamites gigas, is that on which
Saporta founded the species Zamites epibius[1437] from Lower Miocene beds
Page 558
at Bonnieux (Vaucluse), France. Another Tertiary species is mentioned by
Krasser[1438] from Pliocene strata in Brazil as Zamia praecedens Krass. ex
Ett. ms. Ettingshausen has described a Tertiary species from New South
Wales, either Lower Miocene or Upper Eocene in age, as Anomozamites
Muelleri[1439], characterised by truncate segments with simple veins and set
obliquely to the rachis.
While certain form-genera of fronds can only be referred to the
Cycadophyta, in other cases it is possible to assign fronds to a section of
this comprehensive group characterised by a particular type of fertile shoot
and by certain well defined epidermal features.
The investigation of the cuticular structure of various Cycadean fronds
by Nathorst[1440] and especially by Mr Thomas[1441] has supplied a basis of
classification which affords the best criterion of affinity so far available.
The majority of fronds are placed in the Bennettitales while the three genera
Ctenis, Nilssonia, and Ctenopteris (or Ptilozamites[1442]) are placed in the
Nilssoniales.
I. Bennettitales. Epidermal cells characterised by sinuous walls and
generally rectangular; the cuticle is thin; the stomata, confined to the lower
surface of the pinnae, tend to be arranged at right-angles to the veins and
are on a level with the epidermis or very slightly depressed; two large
laterally placed subsidiary cells more or less surround the guard-cells and
these are provided with thickenings of a definite shape (figs. 594, 609).
Genera: Ptilophyllum, Zamites, Otozamites, Dictyozamites, Pterophyllum
and Anomozamites, Taeniopteris, Pseudocycas.
II. Nilssoniales. Epidermal cells with straight walls, not sinuous,
irregular in form, rounded, hexagonal, or rectangular; the stomata are below
the level of the epidermis; the cuticle may be thin or thick. There is no
regular arrangement of the stomata; the guard-cells are surrounded by 6–8
subsidiary cells (fig. 625) which often form an overarching canopy;
thickening lamellae like those on the guard-cells of the Bennettitales are
seldom present.
Genera: Nilssonia, Ctenis, Ctenopteris.
It is a noteworthy fact that the representatives of the smaller group, the
Nilssoniales, in their cuticular features, are more akin than the Bennettitales
Krasser[1438] from Pliocene strata in Brazil as Zamia praecedens Krass. ex
Ett. ms. Ettingshausen has described a Tertiary species from New South
Wales, either Lower Miocene or Upper Eocene in age, as Anomozamites
Muelleri[1439], characterised by truncate segments with simple veins and set
obliquely to the rachis.
While certain form-genera of fronds can only be referred to the
Cycadophyta, in other cases it is possible to assign fronds to a section of
this comprehensive group characterised by a particular type of fertile shoot
and by certain well defined epidermal features.
The investigation of the cuticular structure of various Cycadean fronds
by Nathorst[1440] and especially by Mr Thomas[1441] has supplied a basis of
classification which affords the best criterion of affinity so far available.
The majority of fronds are placed in the Bennettitales while the three genera
Ctenis, Nilssonia, and Ctenopteris (or Ptilozamites[1442]) are placed in the
Nilssoniales.
I. Bennettitales. Epidermal cells characterised by sinuous walls and
generally rectangular; the cuticle is thin; the stomata, confined to the lower
surface of the pinnae, tend to be arranged at right-angles to the veins and
are on a level with the epidermis or very slightly depressed; two large
laterally placed subsidiary cells more or less surround the guard-cells and
these are provided with thickenings of a definite shape (figs. 594, 609).
Genera: Ptilophyllum, Zamites, Otozamites, Dictyozamites, Pterophyllum
and Anomozamites, Taeniopteris, Pseudocycas.
II. Nilssoniales. Epidermal cells with straight walls, not sinuous,
irregular in form, rounded, hexagonal, or rectangular; the stomata are below
the level of the epidermis; the cuticle may be thin or thick. There is no
regular arrangement of the stomata; the guard-cells are surrounded by 6–8
subsidiary cells (fig. 625) which often form an overarching canopy;
thickening lamellae like those on the guard-cells of the Bennettitales are
seldom present.
Genera: Nilssonia, Ctenis, Ctenopteris.
It is a noteworthy fact that the representatives of the smaller group, the
Nilssoniales, in their cuticular features, are more akin than the Bennettitales
Page 559
to modern Cycads. Until definite evidence is obtained as to the nature of the
reproductive organs of Nilssonia, Ctenis, and Ctenopteris it is impossible to
say how closely these genera agree in essential characters with existing
members of the Cycadales. If, as has been suggested, the fertile shoots
known as Beania[1444] belong to Nilssonia their resemblance in plan of
construction to the cones of recent genera, much greater than in the case of
the flowers of the Bennettitales, is in accordance with the evidence of the
epidermal characters.
Reference was made in the second Volume of this book to several genera
founded on fronds which through lack of evidence as to the nature of the
reproductive organs cannot be assigned with certainty either to Ferns or
Cycads: it was stated that the genera Ptilozamites and Ctenopteris are
probably Cycadean, and the structure of the epidermal cells in the latter
genus lends support to this view[1445]. Among other genera of doubtful
position not included in the following descriptions of fronds is Zamiopsis of
Fontaine[1446] founded on large compound fronds from the Potomac
formation: the venation and form of the pinnae are more Fern-like than in
Ctenopteris, but in general habit the two genera are not very dissimilar. The
generic name Zamiopsis is misleading as the species bear no resemblance to
Zamia or Zamites.
I. Bennettitales.
PTILOPHYLLUM. Morris.
The generic name Ptilophyllum was instituted in 1840 for some
specimens of pinnate fronds from Cutch: in this genus Morris[1447] included
with the Indian leaves the English Jurassic species Pterophyllum pecten
Lind. and Hutt.[1448] (figs. 587, etc.) and some other forms. He defined
Ptilophyllum as follows: ‘Fronds pinnate; pinnae closely approximated,
linear, lanceolate, more or less elongate, imbricate at the base, attached
obliquely; base semicircular or rounded; veins equal, slender, parallel.’
Morris adds that he instituted a new genus in preference to Zamites because
of the ‘oblique insertion of the pinnae and their overlapping each other at
the base.’ In a later paper Morris[1449] states that the pinnae of Ptilophyllum
fronds are ‘sometimes auriculed in the upper and sometimes in the lower
part’ of the base of the lamina. In his catalogue[1450] he adopted Endlicher’s
genus Palaeozamia instead of Ptilophyllum. Without discussing the generic
reproductive organs of Nilssonia, Ctenis, and Ctenopteris it is impossible to
say how closely these genera agree in essential characters with existing
members of the Cycadales. If, as has been suggested, the fertile shoots
known as Beania[1444] belong to Nilssonia their resemblance in plan of
construction to the cones of recent genera, much greater than in the case of
the flowers of the Bennettitales, is in accordance with the evidence of the
epidermal characters.
Reference was made in the second Volume of this book to several genera
founded on fronds which through lack of evidence as to the nature of the
reproductive organs cannot be assigned with certainty either to Ferns or
Cycads: it was stated that the genera Ptilozamites and Ctenopteris are
probably Cycadean, and the structure of the epidermal cells in the latter
genus lends support to this view[1445]. Among other genera of doubtful
position not included in the following descriptions of fronds is Zamiopsis of
Fontaine[1446] founded on large compound fronds from the Potomac
formation: the venation and form of the pinnae are more Fern-like than in
Ctenopteris, but in general habit the two genera are not very dissimilar. The
generic name Zamiopsis is misleading as the species bear no resemblance to
Zamia or Zamites.
I. Bennettitales.
PTILOPHYLLUM. Morris.
The generic name Ptilophyllum was instituted in 1840 for some
specimens of pinnate fronds from Cutch: in this genus Morris[1447] included
with the Indian leaves the English Jurassic species Pterophyllum pecten
Lind. and Hutt.[1448] (figs. 587, etc.) and some other forms. He defined
Ptilophyllum as follows: ‘Fronds pinnate; pinnae closely approximated,
linear, lanceolate, more or less elongate, imbricate at the base, attached
obliquely; base semicircular or rounded; veins equal, slender, parallel.’
Morris adds that he instituted a new genus in preference to Zamites because
of the ‘oblique insertion of the pinnae and their overlapping each other at
the base.’ In a later paper Morris[1449] states that the pinnae of Ptilophyllum
fronds are ‘sometimes auriculed in the upper and sometimes in the lower
part’ of the base of the lamina. In his catalogue[1450] he adopted Endlicher’s
genus Palaeozamia instead of Ptilophyllum. Without discussing the generic
Page 560
nomenclature adopted by various authors for the Indian types and similar
fronds it is important to refer briefly to the treatment of Morris’s species by
Oldham and Morris and by Feistmantel. In the first of the series of Memoirs
on Gondwana floras[1451] Ptilophyllum is retained for a section of
Palaeozamia together with Otozamites and Sphenozamites as other
sectional subdivisions: in the subgenus Ptilophyllum are included
Palaeozamia acutifolia and P. cutchensis (fig. 588, A, C), also P. affinis, P.
rigida, and P. bengalensis. The last species is in all probability an
Otozamites: P. affinis and P. rigida are almost certainly indistinguishable
from P. cutchensis. Feistmantel[1452] dealt in detail with the genus
Ptilophyllum: he wrote, ‘with Schimper and Schenk I therefore look upon
this genus as an Indian type especially characterised by its ... more or less
slender leaves, angustate towards the apex and base, and petiolate, with
regularly adfixed leaflets.... The leaflets are equal to each other, for the most
part elongate linear, and auriculate and free at the upper angle at the base,
but adfixed at the lower angle, and each is decurrent behind the upper angle
of the leaflet next below it, thus the leaflets are almost imbricate. The veins
are rather numerous, simple, and forked, and more or less divergent[1453].’
Feistmantel distinguishes certain varieties of P. cutchense (fig. 588, A, C),
none of which appear to be well defined. A specimen from the Rajmahal
Hills with unusually long pinnae, the frond having a breadth of 8 cm., is
described as Ptilophyllum acutifolium var. maximum[1454], but it differs in no
important feature from the smaller and commoner form. The next point to
be considered is the variability of certain species referred by Feistmantel to
Otozamites. He figures specimens from the Jabalpur group as O. Hislopi
Feist. ex Old. ms., O. gracilis (Kurr), O. angustatus Feist. (fig. 588, B) and
O. distans[1455]. An examination of the figured specimens leads me to regard
O. Hislopi and O. gracilis as identical with the Ptilophyllum fronds: the
pinnae exhibit no distinguishing features and there is no reason for a
specific, still less a generic, separation. Otozamites angustatus is
indistinguishable from Otozamites sp. as figured from the Madras coast and
from Ptilophyllum cutchense, P. cutchense var. curvifolium and var.
minimum. The drawings reproduced in fig. 6a, Pl. x. of the Madras flora[1456]
and in fig. 8a, Pl. vi. of the Jabalpur flora[1457] showing auriculate bases are
inaccurate: in all the fronds named the pinnae are straight with rounded
edges precisely as in Ptilophyllum. The conclusion forced upon me by a
comparison of the actual specimens is that the Indian fronds are not
fronds it is important to refer briefly to the treatment of Morris’s species by
Oldham and Morris and by Feistmantel. In the first of the series of Memoirs
on Gondwana floras[1451] Ptilophyllum is retained for a section of
Palaeozamia together with Otozamites and Sphenozamites as other
sectional subdivisions: in the subgenus Ptilophyllum are included
Palaeozamia acutifolia and P. cutchensis (fig. 588, A, C), also P. affinis, P.
rigida, and P. bengalensis. The last species is in all probability an
Otozamites: P. affinis and P. rigida are almost certainly indistinguishable
from P. cutchensis. Feistmantel[1452] dealt in detail with the genus
Ptilophyllum: he wrote, ‘with Schimper and Schenk I therefore look upon
this genus as an Indian type especially characterised by its ... more or less
slender leaves, angustate towards the apex and base, and petiolate, with
regularly adfixed leaflets.... The leaflets are equal to each other, for the most
part elongate linear, and auriculate and free at the upper angle at the base,
but adfixed at the lower angle, and each is decurrent behind the upper angle
of the leaflet next below it, thus the leaflets are almost imbricate. The veins
are rather numerous, simple, and forked, and more or less divergent[1453].’
Feistmantel distinguishes certain varieties of P. cutchense (fig. 588, A, C),
none of which appear to be well defined. A specimen from the Rajmahal
Hills with unusually long pinnae, the frond having a breadth of 8 cm., is
described as Ptilophyllum acutifolium var. maximum[1454], but it differs in no
important feature from the smaller and commoner form. The next point to
be considered is the variability of certain species referred by Feistmantel to
Otozamites. He figures specimens from the Jabalpur group as O. Hislopi
Feist. ex Old. ms., O. gracilis (Kurr), O. angustatus Feist. (fig. 588, B) and
O. distans[1455]. An examination of the figured specimens leads me to regard
O. Hislopi and O. gracilis as identical with the Ptilophyllum fronds: the
pinnae exhibit no distinguishing features and there is no reason for a
specific, still less a generic, separation. Otozamites angustatus is
indistinguishable from Otozamites sp. as figured from the Madras coast and
from Ptilophyllum cutchense, P. cutchense var. curvifolium and var.
minimum. The drawings reproduced in fig. 6a, Pl. x. of the Madras flora[1456]
and in fig. 8a, Pl. vi. of the Jabalpur flora[1457] showing auriculate bases are
inaccurate: in all the fronds named the pinnae are straight with rounded
edges precisely as in Ptilophyllum. The conclusion forced upon me by a
comparison of the actual specimens is that the Indian fronds are not
Page 561
separable into well-defined species and should all be included in
Ptilophyllum cutchense. Moreover in this comprehensive species should be
included the specimens described by Feistmantel as Otozamites Hislopi
(fig. 589), O. angustatus, and O. gracilis. It may well be that a more
detailed investigation of the numerous forms comprised in this protean
species, particularly if specimens are obtained from which cuticular
preparations can be made, may lead to the recognition of additional species
or well-defined varieties. The resemblance between the various forms of P.
pecten from the Jurassic strata of Yorkshire and those of P. cutchense from
India is very striking, and at least in many cases no specific separation is
possible so far at least as the form of the fronds and pinnae is concerned.
The occasional close association of Ptilophyllum fronds and Williamsonia
flowers is an important agreement between the English and Indian fronds
(fig. 590).
Ptilophyllum cutchense. Moreover in this comprehensive species should be
included the specimens described by Feistmantel as Otozamites Hislopi
(fig. 589), O. angustatus, and O. gracilis. It may well be that a more
detailed investigation of the numerous forms comprised in this protean
species, particularly if specimens are obtained from which cuticular
preparations can be made, may lead to the recognition of additional species
or well-defined varieties. The resemblance between the various forms of P.
pecten from the Jurassic strata of Yorkshire and those of P. cutchense from
India is very striking, and at least in many cases no specific separation is
possible so far at least as the form of the fronds and pinnae is concerned.
The occasional close association of Ptilophyllum fronds and Williamsonia
flowers is an important agreement between the English and Indian fronds
(fig. 590).
Page 562
Fig. 587. Ptilophyllum pecten. (British Museum, V. 3795; ¼ nat. size.)
Page 563
Fig. 588. Ptilophyllum pecten. A, C, specimens figured by Feistmantel as
Ptilophyllum cutchense. B, Feistmantel’s Otozamites angustatus. ( ⅚
nat. size; Calcutta Museum.)
Ptilophyllum cutchense. B, Feistmantel’s Otozamites angustatus. ( ⅚
nat. size; Calcutta Museum.)
Page 564
Fig. 589. Ptilophyllum pecten. A frond figured by Feistmantel as
Otozamites Hislopi. A, ⅚ nat. size; B, enlarged (Calcutta Museum).
Otozamites Hislopi. A, ⅚ nat. size; B, enlarged (Calcutta Museum).
Page 565
Fig. 590. Ptilophyllum pecten (P. cutchense) and Williamsonia Blanfordi.
[Drawn from a specimen figured by Feistmantel (762) Pl. xii. fig. 6.]
Fig. 591. Part of the type-specimen of Ptilophyllum cutchense Morris.
(British Museum; × 3.)
[Drawn from a specimen figured by Feistmantel (762) Pl. xii. fig. 6.]
Fig. 591. Part of the type-specimen of Ptilophyllum cutchense Morris.
(British Museum; × 3.)
Page 566
In the first part of the Catalogue of Jurassic
plants from Yorkshire the opinion was
expressed[1458], based on an examination of
Morris’s type-specimen of Ptilophyllum
cutchense and of a large number of English and
other fronds identical with or closely allied to
Pterophyllum pecten Lind. and Hutt., that the Fig. 592. Ptilophyllum
Indian and European fronds belong to the same pecten. (Manchester
genus. In a later paper [1459]
it was maintained Museum, Williamson
that P. cutchense and P. acutifolium are probably Coll. 3726.)
identical with the English type, and a drawing was published—reproduced
in fig. 591—of Morris’s type-specimen. Dr Halle[1460] has discussed the
genus Ptilophyllum and his investigations lead him to a different
conclusion; he, like Zeiller and some other authors, employs Ptilophyllum
in Feistmantel’s sense. The pinna-base is said to agree in its asymmetrical
form with that in Otozamites, while it differs from the symmetrical base of
Zamites pinnae. In Ptilophyllum both edges of the pinna-base are said to
bend down in joining the rachis; at the upper corner the base thus becomes
rounded and for some distance free from the rachis; it is also sometimes a
little auriculate; at the lower edge the pinna is decurrent on the upper
surface of the rachis. In a subsequent paper Halle[1461] repeats the view that
the decurrence of the pinnae by their lower edges is an important
distinguishing feature of Ptilophyllum, thus agreeing with Feistmantel
whose illustrations appear to be confirmatory. The drawings in
Feistmantel’s memoirs are, however, misleading and in some cases
incorrect. An examination of a photograph of Morris’s type-specimen of P.
cutchense led Halle to conclude that the two edges of the pinna-base bend
downwards on joining the rachis as described by Feistmantel. This feature
is not shown in the drawing reproduced in fig. 591: it is clear that either the
drawing is incorrect or that there has been some mistake in the
interpretation of the photograph. Through the courtesy of Dr Halle I have
been able to examine the actual print: when viewed in its correct position
the two edges of the pinnae appear to bend down as described by Halle, but
if it is examined in the reverse position the lower angle of the pinnae is seen
to be slightly rounded as in fig. 591, the apparent decurrence being due to a
confusion between the appressed lower edge of one pinna, which is faintly
shown, and the stronger downward trend of the upper edge of the pinna
plants from Yorkshire the opinion was
expressed[1458], based on an examination of
Morris’s type-specimen of Ptilophyllum
cutchense and of a large number of English and
other fronds identical with or closely allied to
Pterophyllum pecten Lind. and Hutt., that the Fig. 592. Ptilophyllum
Indian and European fronds belong to the same pecten. (Manchester
genus. In a later paper [1459]
it was maintained Museum, Williamson
that P. cutchense and P. acutifolium are probably Coll. 3726.)
identical with the English type, and a drawing was published—reproduced
in fig. 591—of Morris’s type-specimen. Dr Halle[1460] has discussed the
genus Ptilophyllum and his investigations lead him to a different
conclusion; he, like Zeiller and some other authors, employs Ptilophyllum
in Feistmantel’s sense. The pinna-base is said to agree in its asymmetrical
form with that in Otozamites, while it differs from the symmetrical base of
Zamites pinnae. In Ptilophyllum both edges of the pinna-base are said to
bend down in joining the rachis; at the upper corner the base thus becomes
rounded and for some distance free from the rachis; it is also sometimes a
little auriculate; at the lower edge the pinna is decurrent on the upper
surface of the rachis. In a subsequent paper Halle[1461] repeats the view that
the decurrence of the pinnae by their lower edges is an important
distinguishing feature of Ptilophyllum, thus agreeing with Feistmantel
whose illustrations appear to be confirmatory. The drawings in
Feistmantel’s memoirs are, however, misleading and in some cases
incorrect. An examination of a photograph of Morris’s type-specimen of P.
cutchense led Halle to conclude that the two edges of the pinna-base bend
downwards on joining the rachis as described by Feistmantel. This feature
is not shown in the drawing reproduced in fig. 591: it is clear that either the
drawing is incorrect or that there has been some mistake in the
interpretation of the photograph. Through the courtesy of Dr Halle I have
been able to examine the actual print: when viewed in its correct position
the two edges of the pinnae appear to bend down as described by Halle, but
if it is examined in the reverse position the lower angle of the pinnae is seen
to be slightly rounded as in fig. 591, the apparent decurrence being due to a
confusion between the appressed lower edge of one pinna, which is faintly
shown, and the stronger downward trend of the upper edge of the pinna
Page 567
next below. The upper edges of the pinnae are more prominent because they
are less appressed to the rachis while the lower half of the base is closer to
the rachis and is frequently, though not in Morris’s specimen, overlapped by
the upper edge of the next lower pinna. A re-examination of the type-
specimen in the British Museum confirms this interpretation. The pinnae of
Ptilophyllum are characterised by their attachment to the upper face of the
rachis which they almost completely cover; the upper angle is rounded and
in a few cases auriculate (fig. 592); the lower angle of the base is slightly
rounded and not infrequently hidden by the imbrication of the adjacent
pinna; it is occasionally auriculate (fig. 593). The pinnae are attached by
nearly the whole base, but the upper angle is free. The veins are parallel,
sub-parallel or, especially in the proximal portion of the lamina, oblique.
The pinnae are linear, varying considerably in relation of length to breadth
and in the form of the apex; they are straight or more or less falcate. The
epidermal cells of such Ptilophyllum fronds as have been examined are
characterised by strongly looped or sinuous walls; the stomata, confined to
the lower surface, are roughly circular and the guard-cells are at right-
angles to the veins and not appreciably sunk. Fig. 594 represents the
appearance of a stoma in surface-view: ‘on either side of the central slit-like
pore are two elliptical or hemispherical structures; they are somewhat
flattened when they abut on the pore, and have rounded ends.... Between
these and the subsidiary cells lie two other thickened patches, more or less
hemispherical in shape, and apparently overlying the central structures.’ On
the analogy of similar appearances in recent Cycads Mr Thomas[1462]
interprets the two pairs of thickened patches as belonging to the upper and
lower sides of the highly inclined guard-cells. This author calls special
attention to the abundance on some of the fronds included in the aggregate
species P. pecten of regular rows of circular hair-scars preserved as small
annulate projections, ·03–·04 mm. in diameter. A comparison of the cuticles
of different forms of Ptilophyllum pecten enabled Thomas to recognise
more than one type: for one of these the name Ptilophyllum hirsutum is
proposed. It is by such work as this that we may hope to discover
differentiating characters.
are less appressed to the rachis while the lower half of the base is closer to
the rachis and is frequently, though not in Morris’s specimen, overlapped by
the upper edge of the next lower pinna. A re-examination of the type-
specimen in the British Museum confirms this interpretation. The pinnae of
Ptilophyllum are characterised by their attachment to the upper face of the
rachis which they almost completely cover; the upper angle is rounded and
in a few cases auriculate (fig. 592); the lower angle of the base is slightly
rounded and not infrequently hidden by the imbrication of the adjacent
pinna; it is occasionally auriculate (fig. 593). The pinnae are attached by
nearly the whole base, but the upper angle is free. The veins are parallel,
sub-parallel or, especially in the proximal portion of the lamina, oblique.
The pinnae are linear, varying considerably in relation of length to breadth
and in the form of the apex; they are straight or more or less falcate. The
epidermal cells of such Ptilophyllum fronds as have been examined are
characterised by strongly looped or sinuous walls; the stomata, confined to
the lower surface, are roughly circular and the guard-cells are at right-
angles to the veins and not appreciably sunk. Fig. 594 represents the
appearance of a stoma in surface-view: ‘on either side of the central slit-like
pore are two elliptical or hemispherical structures; they are somewhat
flattened when they abut on the pore, and have rounded ends.... Between
these and the subsidiary cells lie two other thickened patches, more or less
hemispherical in shape, and apparently overlying the central structures.’ On
the analogy of similar appearances in recent Cycads Mr Thomas[1462]
interprets the two pairs of thickened patches as belonging to the upper and
lower sides of the highly inclined guard-cells. This author calls special
attention to the abundance on some of the fronds included in the aggregate
species P. pecten of regular rows of circular hair-scars preserved as small
annulate projections, ·03–·04 mm. in diameter. A comparison of the cuticles
of different forms of Ptilophyllum pecten enabled Thomas to recognise
more than one type: for one of these the name Ptilophyllum hirsutum is
proposed. It is by such work as this that we may hope to discover
differentiating characters.
Page 568
Fig. 593. Ptilophyllum pecten. From the Lower Estuarine beds,
Cleveland, Yorkshire. (After Thomas; nat. size.)
The different forms of Williamsonia flowers found
in association with fronds of the Ptilophyllum habit
also point to the inclusion of more than a single
species under the group-species P. pecten. As
additional evidence is obtained further analysis will be
possible, but in dealing with impressions which
include specimens transitional from one form of frond
to another, the most convenient and to my mind the
most logical course is to treat a species as an Fig. 594.
aggregate- or group-species. Some authors believe Ptilophyllum
that the two fronds described by Phillips as Cycadites pecten; stoma.
pecten and C. pectinoides are distinct species[1463], but (After Thomas
there would seem to be no adequate reason for this and Bancroft.)
view. The fronds described by Heer[1464] from the Lower Cretaceous of
Greenland as species of Zamites and similar leaves from Graham Land
included in that genus by Halle[1465] are in my opinion inseparable from
Ptilophyllum, and this applies equally to Otozamites Hislopi (Old.) (fig.
589) and O. abbreviatus as figured by Feistmantel and by Halle. The
Cleveland, Yorkshire. (After Thomas; nat. size.)
The different forms of Williamsonia flowers found
in association with fronds of the Ptilophyllum habit
also point to the inclusion of more than a single
species under the group-species P. pecten. As
additional evidence is obtained further analysis will be
possible, but in dealing with impressions which
include specimens transitional from one form of frond
to another, the most convenient and to my mind the
most logical course is to treat a species as an Fig. 594.
aggregate- or group-species. Some authors believe Ptilophyllum
that the two fronds described by Phillips as Cycadites pecten; stoma.
pecten and C. pectinoides are distinct species[1463], but (After Thomas
there would seem to be no adequate reason for this and Bancroft.)
view. The fronds described by Heer[1464] from the Lower Cretaceous of
Greenland as species of Zamites and similar leaves from Graham Land
included in that genus by Halle[1465] are in my opinion inseparable from
Ptilophyllum, and this applies equally to Otozamites Hislopi (Old.) (fig.
589) and O. abbreviatus as figured by Feistmantel and by Halle. The
Page 569
nomenclature of Cycadean fronds having the habit of Ptilophyllum pecten is
a great difficulty: after carefully reconsidering the whole question and
comparing Feistmantel’s figured specimens with the large series of English
fronds the conclusion reached is that the characters exhibited by ordinary
impressions do not admit of any satisfactory grouping under well-defined
specific types. In the first place, as already indicated, the use by some
authors of the generic names Ptilophyllum, Otozamites, and Zamites creates
a false impression of the degree of difference between the numerous forms
of frond agreeing more or less closely with the specimens on which were
founded the species Ptilophyllum acutifolium, P. cutchense, P. pecten, and
P. pectinoides (figs. 587, 591, 595, etc.). In his important memoir on the
Jurassic flora of Graham Land Halle[1466] discusses the limitation of
Ptilophyllum, Zamites, and Otozamites. He employs Zamites for fronds with
linear pinnae attached to the upper face of the rachis by a base which is
more or less, but often very little, rounded and always asymmetrical, with
or without a basal callosity: fronds of the type Z. gigas he includes in the
section Euzamites, while Z. borealis and similar forms (fig. 597) are
referred to a second section, Subzamites. It is in the sense of Halle’s section
Euzamites that the generic name Zamites is employed in this chapter. On the
other hand the fronds grouped by Halle as Subzamites have pinnae with the
basal angles of the lamina very slightly rounded precisely as in
Ptilophyllum as seen in fig. 596 (cf. fig. 598 which represents fronds
referred by Halle to Zamites); and they are not distinguished by any feature
of generic importance from Ptilophyllum as defined on page 519. The
species Zamites pusillus, Z. Anderssoni, and Z. antarcticus (fig. 598)
described by Halle from Graham Land as well as Heer’s Arctic forms[1467] Z.
borealis (fig. 597), Z. speciosus, Z. brevipennis, and others are transferred
to Ptilophyllum as types agreeing very closely with P. pecten and in some
cases not clearly distinguishable from it even specifically.
Otozamites is the name employed by Halle for fronds with pinnae having
contracted, asymmetrical and auriculate, bases, the anterior lobe being more
developed than the posterior. The asymmetry of the pinna-base is
considered an essential feature. As Halle states it is very difficult in some
instances to draw a distinction between Otozamites and Ptilophyllum. As
used in this chapter Otozamites signifies fronds with pinnae characterised
by an auriculate base, a lamina usually broader than in Ptilophyllum, and by
more spreading veins (fig. 604). The not infrequent occurrence of auriculate
a great difficulty: after carefully reconsidering the whole question and
comparing Feistmantel’s figured specimens with the large series of English
fronds the conclusion reached is that the characters exhibited by ordinary
impressions do not admit of any satisfactory grouping under well-defined
specific types. In the first place, as already indicated, the use by some
authors of the generic names Ptilophyllum, Otozamites, and Zamites creates
a false impression of the degree of difference between the numerous forms
of frond agreeing more or less closely with the specimens on which were
founded the species Ptilophyllum acutifolium, P. cutchense, P. pecten, and
P. pectinoides (figs. 587, 591, 595, etc.). In his important memoir on the
Jurassic flora of Graham Land Halle[1466] discusses the limitation of
Ptilophyllum, Zamites, and Otozamites. He employs Zamites for fronds with
linear pinnae attached to the upper face of the rachis by a base which is
more or less, but often very little, rounded and always asymmetrical, with
or without a basal callosity: fronds of the type Z. gigas he includes in the
section Euzamites, while Z. borealis and similar forms (fig. 597) are
referred to a second section, Subzamites. It is in the sense of Halle’s section
Euzamites that the generic name Zamites is employed in this chapter. On the
other hand the fronds grouped by Halle as Subzamites have pinnae with the
basal angles of the lamina very slightly rounded precisely as in
Ptilophyllum as seen in fig. 596 (cf. fig. 598 which represents fronds
referred by Halle to Zamites); and they are not distinguished by any feature
of generic importance from Ptilophyllum as defined on page 519. The
species Zamites pusillus, Z. Anderssoni, and Z. antarcticus (fig. 598)
described by Halle from Graham Land as well as Heer’s Arctic forms[1467] Z.
borealis (fig. 597), Z. speciosus, Z. brevipennis, and others are transferred
to Ptilophyllum as types agreeing very closely with P. pecten and in some
cases not clearly distinguishable from it even specifically.
Otozamites is the name employed by Halle for fronds with pinnae having
contracted, asymmetrical and auriculate, bases, the anterior lobe being more
developed than the posterior. The asymmetry of the pinna-base is
considered an essential feature. As Halle states it is very difficult in some
instances to draw a distinction between Otozamites and Ptilophyllum. As
used in this chapter Otozamites signifies fronds with pinnae characterised
by an auriculate base, a lamina usually broader than in Ptilophyllum, and by
more spreading veins (fig. 604). The not infrequent occurrence of auriculate
Page 570
pinnae on fronds (fig. 603, A) which cannot be separated from typical
examples of P. pecten illustrates the narrow dividing line as regards the
form of the pinna-base between Ptilophyllum and Otozamites. The Indian
species O. Hislopi (fig. 589) and O. abbreviatus, to which Halle refers some
Antarctic fronds, cannot be distinguished from the English P. pecten or
Feistmantel’s and Morris’s Indian fronds described as P. cutchense and P.
acutifolium: these forms are therefore included in Ptilophyllum.
Ptilophyllum (Williamsonia) pecten (Phillips).
This designation is employed in a wide sense for a group of fronds
exhibiting a considerable range in size, in the relative breadth and length of
the linear pinnae, and in other features. Under P. pecten are included (i) the
English fronds from Yorkshire first described by Phillips[1468] as Cycadites
pecten and C. pectinoides, the former from the Middle shale, the latter from
the Lower shale of the Yorkshire coast, together with the Stonesfield slate
specimens named by Sternberg[1469] Polypodiolites pectiniformis (fig. 595)
and by Brongniart[1470] and Lindley and Hutton[1471] Zamia pectinata; (ii) the
Indian specimens already considered and (iii) numerous examples recorded
under different names from Jurassic strata in many countries. Fronds from
the Yorkshire coast named by Brongniart[1472] Zamia Goldiei, though
regarded by some authors as examples of Otozamites, are probably
referable to P. pecten. Andrae’s Pterophyllum rigidum[1473] (fig. 596) from
Steierdorf is almost certainly a form of Ptilophyllum pecten. The specimen
shown in fig. 587 is one of the few examples of fronds apparently preserved
in their original position attached in a cluster to a Williamsonia
(Bucklandia) type of stem. The range in size and form of the pinnae is
illustrated in figs. 588, 592, 593.
examples of P. pecten illustrates the narrow dividing line as regards the
form of the pinna-base between Ptilophyllum and Otozamites. The Indian
species O. Hislopi (fig. 589) and O. abbreviatus, to which Halle refers some
Antarctic fronds, cannot be distinguished from the English P. pecten or
Feistmantel’s and Morris’s Indian fronds described as P. cutchense and P.
acutifolium: these forms are therefore included in Ptilophyllum.
Ptilophyllum (Williamsonia) pecten (Phillips).
This designation is employed in a wide sense for a group of fronds
exhibiting a considerable range in size, in the relative breadth and length of
the linear pinnae, and in other features. Under P. pecten are included (i) the
English fronds from Yorkshire first described by Phillips[1468] as Cycadites
pecten and C. pectinoides, the former from the Middle shale, the latter from
the Lower shale of the Yorkshire coast, together with the Stonesfield slate
specimens named by Sternberg[1469] Polypodiolites pectiniformis (fig. 595)
and by Brongniart[1470] and Lindley and Hutton[1471] Zamia pectinata; (ii) the
Indian specimens already considered and (iii) numerous examples recorded
under different names from Jurassic strata in many countries. Fronds from
the Yorkshire coast named by Brongniart[1472] Zamia Goldiei, though
regarded by some authors as examples of Otozamites, are probably
referable to P. pecten. Andrae’s Pterophyllum rigidum[1473] (fig. 596) from
Steierdorf is almost certainly a form of Ptilophyllum pecten. The specimen
shown in fig. 587 is one of the few examples of fronds apparently preserved
in their original position attached in a cluster to a Williamsonia
(Bucklandia) type of stem. The range in size and form of the pinnae is
illustrated in figs. 588, 592, 593.
Page 571
Fig. 596. Ptilophyllum pecten.
Andrae’s Pterophyllum rigidum
from Steierdorf, Banat. (British
Museum, No. 41438; nat. size.)
Fig. 595. Ptilophyllum pecten. The
specimen figured by Sternberg as
Polypodiolites pectiniformis.
(Oxford Museum; ⅚ nat. size.)
Fronds linear, tapering gradually towards the base and apex, often
characterised by a marked uniformity in breadth. The pinnae, short or
comparatively broad or long and narrow, are straight or more or less falcate;
the apex is obtuse or acute or the upper margin of the lamina may be almost
straight and the lower edge curved abruptly upwards at the apex; the pinnae
are usually attached obliquely to the rachis but may be almost at right-
angles; with the exception of the upper angle, the whole of the base is
attached to the frond-axis; the base of the lamina may be symmetrical, both
angles being slightly rounded, or asymmetrical, the upper or less frequently
the lower corner being auriculate (figs. 592, 593). There is no basal
callosity on the lamina nor is there a median sinus. The veins are more or
less spreading at the base but for the most part parallel. The features of the
Andrae’s Pterophyllum rigidum
from Steierdorf, Banat. (British
Museum, No. 41438; nat. size.)
Fig. 595. Ptilophyllum pecten. The
specimen figured by Sternberg as
Polypodiolites pectiniformis.
(Oxford Museum; ⅚ nat. size.)
Fronds linear, tapering gradually towards the base and apex, often
characterised by a marked uniformity in breadth. The pinnae, short or
comparatively broad or long and narrow, are straight or more or less falcate;
the apex is obtuse or acute or the upper margin of the lamina may be almost
straight and the lower edge curved abruptly upwards at the apex; the pinnae
are usually attached obliquely to the rachis but may be almost at right-
angles; with the exception of the upper angle, the whole of the base is
attached to the frond-axis; the base of the lamina may be symmetrical, both
angles being slightly rounded, or asymmetrical, the upper or less frequently
the lower corner being auriculate (figs. 592, 593). There is no basal
callosity on the lamina nor is there a median sinus. The veins are more or
less spreading at the base but for the most part parallel. The features of the
Page 572
epidermal cells and stomata are mentioned in the general account of the
genus. Fertile shoots of plants with this type of frond are described under
Williamsonia. Very little is known of the stems which bore Ptilophyllum
fronds, but as stated on page 488 Indian specimens show leaves of
Ptilophyllum cutchense attached to a piece of stem (fig. 579) having the
characters of Bucklandia and characterised by a xylem-cylinder denser than
in recent Cycads; the structure of the wood at least in the Indian stem is
rather pycnoxylic than manoxylic.
The fronds grouped under Ptilophyllum pecten are very widely
distributed in Jurassic floras; they are recorded from many localities in
Europe, from Turkestan[1474], India, Graham Land[1475], Patagonia[1476], and
elsewhere.
As thus defined this ‘species,’ or more correctly this group of forms,
undoubtedly includes more than one species in the strict sense, but without
additional data it is maintained that the recognition of clearly defined
specific types or varieties is beyond our power. It may be urged that in view
of the wide geographical range of the Ptilophyllum pecten type of frond and
the admitted probability that several species in the narrower sense are
represented, distinctive specific names should be retained even though
under such designations are included forms that, so far as can be seen from
impressions, exhibit no constant distinguishing features. My purpose is to
emphasise the futility of attempting to found well-marked species on the
available material. The student must decide for himself what course to
pursue, whether to retain such a specific name as cutchense for the Indian
fronds or to employ that and other specific names as designations of
geographical types differing in no clearly defined or constant characters
from examples of the English Ptilophyllum pecten. A comparative
examination of the cuticular membranes in the comparatively few cases
where that is possible would probably furnish a basis for a satisfactory
subdivision of the group-species.
The names Ptilophyllum Anderssoni, P. boreale, and P. antarcticum are
retained for certain forms selected from a number of closely allied types
partly on the ground that these fronds exhibit some more or less well-
marked distinctive characters and in part as a recognition of the existence of
geographical forms.
genus. Fertile shoots of plants with this type of frond are described under
Williamsonia. Very little is known of the stems which bore Ptilophyllum
fronds, but as stated on page 488 Indian specimens show leaves of
Ptilophyllum cutchense attached to a piece of stem (fig. 579) having the
characters of Bucklandia and characterised by a xylem-cylinder denser than
in recent Cycads; the structure of the wood at least in the Indian stem is
rather pycnoxylic than manoxylic.
The fronds grouped under Ptilophyllum pecten are very widely
distributed in Jurassic floras; they are recorded from many localities in
Europe, from Turkestan[1474], India, Graham Land[1475], Patagonia[1476], and
elsewhere.
As thus defined this ‘species,’ or more correctly this group of forms,
undoubtedly includes more than one species in the strict sense, but without
additional data it is maintained that the recognition of clearly defined
specific types or varieties is beyond our power. It may be urged that in view
of the wide geographical range of the Ptilophyllum pecten type of frond and
the admitted probability that several species in the narrower sense are
represented, distinctive specific names should be retained even though
under such designations are included forms that, so far as can be seen from
impressions, exhibit no constant distinguishing features. My purpose is to
emphasise the futility of attempting to found well-marked species on the
available material. The student must decide for himself what course to
pursue, whether to retain such a specific name as cutchense for the Indian
fronds or to employ that and other specific names as designations of
geographical types differing in no clearly defined or constant characters
from examples of the English Ptilophyllum pecten. A comparative
examination of the cuticular membranes in the comparatively few cases
where that is possible would probably furnish a basis for a satisfactory
subdivision of the group-species.
The names Ptilophyllum Anderssoni, P. boreale, and P. antarcticum are
retained for certain forms selected from a number of closely allied types
partly on the ground that these fronds exhibit some more or less well-
marked distinctive characters and in part as a recognition of the existence of
geographical forms.
Page 573
Ptilophyllum boreale (Heer).
Heer[1477] described numerous well-preserved impressions of pinnate
fronds from the Lower Cretaceous plant-beds of Kome, Greenland, which
he referred to several species of Zamites though the differences between
them are hardly of specific rank. An inspection of several of the figured
specimens in the Stockholm Museum showed that Heer’s drawings are in
the main accurate. Zamites borealis (fig. 597) is characterised by small
linear pinnae attached to the upper face of the rachis, the stoutness of which
is a noteworthy feature; the veins are parallel and simple. In the shape of the
pinnae, including the base-characters, this species agrees closely with P.
pecten. The slightly falcate or straight pinnae are 1·7–2 mm. broad and
reach a length of 15 mm.; in Z. speciosum Heer, probably specifically
identical with P. boreale, the pinnae are relatively longer, and in Z.
brevipennis Heer they resemble the shorter pinnae of some of the narrow
fronds of P. pecten.
A preparation of the cuticle of a pinna of P. boreale made by Mr Thomas
from a specimen in the Stockholm Museum shows a marked difference
between the upper and lower epidermis: the cells on the upper surface of the
lamina have very thick and sinuous walls precisely as in P. pecten, but the
cells are often broader than long and not elongated parallel to the long axis
of the pinna; those of the lower epidermis are thinner and less clearly
preserved: the stomata, which appear to be like those of P. pecten, are
scattered and not in rows.
Heer[1477] described numerous well-preserved impressions of pinnate
fronds from the Lower Cretaceous plant-beds of Kome, Greenland, which
he referred to several species of Zamites though the differences between
them are hardly of specific rank. An inspection of several of the figured
specimens in the Stockholm Museum showed that Heer’s drawings are in
the main accurate. Zamites borealis (fig. 597) is characterised by small
linear pinnae attached to the upper face of the rachis, the stoutness of which
is a noteworthy feature; the veins are parallel and simple. In the shape of the
pinnae, including the base-characters, this species agrees closely with P.
pecten. The slightly falcate or straight pinnae are 1·7–2 mm. broad and
reach a length of 15 mm.; in Z. speciosum Heer, probably specifically
identical with P. boreale, the pinnae are relatively longer, and in Z.
brevipennis Heer they resemble the shorter pinnae of some of the narrow
fronds of P. pecten.
A preparation of the cuticle of a pinna of P. boreale made by Mr Thomas
from a specimen in the Stockholm Museum shows a marked difference
between the upper and lower epidermis: the cells on the upper surface of the
lamina have very thick and sinuous walls precisely as in P. pecten, but the
cells are often broader than long and not elongated parallel to the long axis
of the pinna; those of the lower epidermis are thinner and less clearly
preserved: the stomata, which appear to be like those of P. pecten, are
scattered and not in rows.
Page 574
Fig. 597. Ptilophyllum boreale (Heer). Drawn from one of the specimens
from the Lower Cretaceous beds at Ekkorfat, Greenland, figured
by Heer. (Stockholm Museum; nat. size and a few pinnae
enlarged.)
Ptilophyllum antarcticum (Halle).
from the Lower Cretaceous beds at Ekkorfat, Greenland, figured
by Heer. (Stockholm Museum; nat. size and a few pinnae
enlarged.)
Ptilophyllum antarcticum (Halle).
Page 575
The fronds from the Jurassic rocks of Graham Land, described by Halle
as Zamites antarcticus[1478], are very similar to some forms of P. pecten and
to P. boreale and other Greenland forms; the linear subacute pinnae are
attached to the upper face of the rachis at a wide angle and the base of the
lamina is truncate and may be very slightly constricted. The veins are dense,
as many as 5 in 1 mm., and they are occasionally forked near the base (fig.
598, A).
Fig. 598. A, A′, Ptilophyllum antarcticum. B, P. Anderssoni. (After
Halle.)
Ptilophyllum Anderssoni (Halle).
This Graham Land species (fig. 598, B), referred by Halle to Zamites[1479],
is of the same general type as P. pecten, but is characterised by a coarser
venation and by the wider angle of attachment of the pinnae.
Ptilophyllum Dunkerianum (Goeppert).
Goeppert[1480] proposed the name Pterophyllum Dunkerianum for some
specimens from the Wealden of North Germany which were afterwards
figured by Dunker[1481]. Miquel[1482] included the species in his genus
Dioonites and this name has been adopted by other authors. Attention has
been drawn to the inconsistent use of the title Dioonites[1483], and I have
as Zamites antarcticus[1478], are very similar to some forms of P. pecten and
to P. boreale and other Greenland forms; the linear subacute pinnae are
attached to the upper face of the rachis at a wide angle and the base of the
lamina is truncate and may be very slightly constricted. The veins are dense,
as many as 5 in 1 mm., and they are occasionally forked near the base (fig.
598, A).
Fig. 598. A, A′, Ptilophyllum antarcticum. B, P. Anderssoni. (After
Halle.)
Ptilophyllum Anderssoni (Halle).
This Graham Land species (fig. 598, B), referred by Halle to Zamites[1479],
is of the same general type as P. pecten, but is characterised by a coarser
venation and by the wider angle of attachment of the pinnae.
Ptilophyllum Dunkerianum (Goeppert).
Goeppert[1480] proposed the name Pterophyllum Dunkerianum for some
specimens from the Wealden of North Germany which were afterwards
figured by Dunker[1481]. Miquel[1482] included the species in his genus
Dioonites and this name has been adopted by other authors. Attention has
been drawn to the inconsistent use of the title Dioonites[1483], and I have
Page 576
previously employed the name in a sense similar to that in which it has been
adopted by Nathorst, that is for fronds with long and narrow pinnae without
any basal constriction and not auriculate, attached more or less at right-
angles to the upper face of the rachis; but so defined Dioonites differs in no
essential particular from forms of Ptilophyllum or from fronds referred by
authors to Schimper’s genus Ctenophyllum. The name Ctenophyllum[1484]
was instituted for certain fronds differing in some points from Otozamites
and Dioonites. One such type is Ctenophyllum (Ptilophyllum) pecten (Lind.
and Hutt.): this is quoted in Zittel’s Handbuch as a typical representative of
the genus. Schimper followed Feistmantel in his definition of Ptilophyllum,
a definition which is not in accordance with the characters of the fronds on
which it was founded by Morris. Fontaine, on the other hand, has applied
Ctenophyllum to fronds of a different type which are now included in the
genus Pseudoctenis. There would seem to be no adequate ground for the
retention of Ctenophyllum as a generic designation.
The Wealden species P. Dunkerianum is characterised by the following
features: rachis fairly stout, pinnae approximate, linear 2–3 mm. broad and
reaching a length of 11 cm. or more, gradually narrowed towards the apex,
attached in two almost contiguous rows to the upper face of the frond-axis:
the lower margin of the lamina may be slightly decurrent, e.g. in the apical
part of the frond or very slightly broadened and bluntly rounded. The
pinnae are attached at right-angles or, near the apex, obliquely; veins 5–6,
parallel. The epidermal cells as figured by Schenk[1485] have very sinuous
walls and are identical with those of the English and Indian forms of the
group-species P. pecten; the stomata are confined to the lower surface. If
Schenk’s drawings of the stomata are correct they differ from those of other
species of the genus in their simpler structure; there are no subsidiary cells
and the guard-cells show no cuticularised bands. In habit this species
resembles Encephalartos Ghellinckii Lehm. (fig. 382). The superficial
resemblance of the narrow linear pinnae to those of Cycadites led Dunker
and Schenk to refer to that genus some specimens which have since been
described as identical with P. Dunkerianum.
ZAMITES. Brongniart.
In the first instance the generic name Zamites was used in addition to
Zamia for certain pinnate fronds including species[1486], such as Z. Bechei,
which are now regarded as typical examples of Otozamites. Subsequently
adopted by Nathorst, that is for fronds with long and narrow pinnae without
any basal constriction and not auriculate, attached more or less at right-
angles to the upper face of the rachis; but so defined Dioonites differs in no
essential particular from forms of Ptilophyllum or from fronds referred by
authors to Schimper’s genus Ctenophyllum. The name Ctenophyllum[1484]
was instituted for certain fronds differing in some points from Otozamites
and Dioonites. One such type is Ctenophyllum (Ptilophyllum) pecten (Lind.
and Hutt.): this is quoted in Zittel’s Handbuch as a typical representative of
the genus. Schimper followed Feistmantel in his definition of Ptilophyllum,
a definition which is not in accordance with the characters of the fronds on
which it was founded by Morris. Fontaine, on the other hand, has applied
Ctenophyllum to fronds of a different type which are now included in the
genus Pseudoctenis. There would seem to be no adequate ground for the
retention of Ctenophyllum as a generic designation.
The Wealden species P. Dunkerianum is characterised by the following
features: rachis fairly stout, pinnae approximate, linear 2–3 mm. broad and
reaching a length of 11 cm. or more, gradually narrowed towards the apex,
attached in two almost contiguous rows to the upper face of the frond-axis:
the lower margin of the lamina may be slightly decurrent, e.g. in the apical
part of the frond or very slightly broadened and bluntly rounded. The
pinnae are attached at right-angles or, near the apex, obliquely; veins 5–6,
parallel. The epidermal cells as figured by Schenk[1485] have very sinuous
walls and are identical with those of the English and Indian forms of the
group-species P. pecten; the stomata are confined to the lower surface. If
Schenk’s drawings of the stomata are correct they differ from those of other
species of the genus in their simpler structure; there are no subsidiary cells
and the guard-cells show no cuticularised bands. In habit this species
resembles Encephalartos Ghellinckii Lehm. (fig. 382). The superficial
resemblance of the narrow linear pinnae to those of Cycadites led Dunker
and Schenk to refer to that genus some specimens which have since been
described as identical with P. Dunkerianum.
ZAMITES. Brongniart.
In the first instance the generic name Zamites was used in addition to
Zamia for certain pinnate fronds including species[1486], such as Z. Bechei,
which are now regarded as typical examples of Otozamites. Subsequently
Page 577
Brongniart gave up Zamia for fossil fronds and applied Zamites to fronds
with entire pinnae, not truncate at the apex and not decurrent but slightly
constricted at the base. Braun’s two genera Podozamites and Pterozamites
were relegated to the position of subgenera. The name Podozamites has
been employed by Schenk[1487] for specimens now included in Zamites, and
Zamites is used by him[1488] for some fossils which are examples of
Podozamites as generally understood. Goeppert’s definition[1489] of Zamites
includes fronds with pinnae of the Otozamites type, and this author
pertinently compares Zamites with recent Encephalartos leaves. Pomel[1490]
proposed the name Crossozamia for certain fronds of the Zamites type, but
this genus with several others instituted by the same author has not been
adopted. Bornemann[1491] described Zamites as comprising species with a
greater or less resemblance to the fronds of recent Zamias.
As defined below, Zamites fronds may be compared with those of some
species of Encephalartos, Ceratozamia, and Macrozamia. There has been
considerable difference of opinion with regard to the range of form in the
pinnae that it is advisable to include in Zamites. The name Zamiophyllum
was proposed by Nathorst[1492] for a Wealden species, described by
Ettingshausen as Pterophyllum Buchianum (fig. 601, A–C), characterised
by a decrease in the breadth of the linear pinnae towards the point of
attachment and, according to Nathorst’s description, by the lateral
attachment of the pinnae. An examination of specimens of this type from
English rocks[1493] enabled me to show that the pinnae are attached to the
upper face of the rachis. Zeiller[1494] has also included Zamiophyllum in
Zamites, but Halle’s recent definition[1495] of the latter genus excludes fronds
of the Zamiophyllum type. Schimper instituted the name Glossozamites[1496]
for fronds bearing pinnae with rounded and slightly contracted bases and
borne on grooves on the upper surface of the rachis (fig. 601, F). In
venation the pinnae agree with those of Otozamites but the base is not
auriculate. Kurr’s Liassic species Pterophyllum oblongifolium[1497] included
by Schimper in Glossozamites is probably an Otozamites. Another species
referred to this genus is Schenk’s Podozamites Zitteli[1498] from the Urgonian
of Austria (fig. 601, F): in this species the slightly falcate pinnae with
obtuse apices have rounded and not auriculate bases and there is some
evidence of a basal callosity. This species agrees so closely with such a
typical Zamites as Z. gigas that it is difficult to see on what grounds the
retention of Glossozamites is desirable. A Portuguese specimen referred by
with entire pinnae, not truncate at the apex and not decurrent but slightly
constricted at the base. Braun’s two genera Podozamites and Pterozamites
were relegated to the position of subgenera. The name Podozamites has
been employed by Schenk[1487] for specimens now included in Zamites, and
Zamites is used by him[1488] for some fossils which are examples of
Podozamites as generally understood. Goeppert’s definition[1489] of Zamites
includes fronds with pinnae of the Otozamites type, and this author
pertinently compares Zamites with recent Encephalartos leaves. Pomel[1490]
proposed the name Crossozamia for certain fronds of the Zamites type, but
this genus with several others instituted by the same author has not been
adopted. Bornemann[1491] described Zamites as comprising species with a
greater or less resemblance to the fronds of recent Zamias.
As defined below, Zamites fronds may be compared with those of some
species of Encephalartos, Ceratozamia, and Macrozamia. There has been
considerable difference of opinion with regard to the range of form in the
pinnae that it is advisable to include in Zamites. The name Zamiophyllum
was proposed by Nathorst[1492] for a Wealden species, described by
Ettingshausen as Pterophyllum Buchianum (fig. 601, A–C), characterised
by a decrease in the breadth of the linear pinnae towards the point of
attachment and, according to Nathorst’s description, by the lateral
attachment of the pinnae. An examination of specimens of this type from
English rocks[1493] enabled me to show that the pinnae are attached to the
upper face of the rachis. Zeiller[1494] has also included Zamiophyllum in
Zamites, but Halle’s recent definition[1495] of the latter genus excludes fronds
of the Zamiophyllum type. Schimper instituted the name Glossozamites[1496]
for fronds bearing pinnae with rounded and slightly contracted bases and
borne on grooves on the upper surface of the rachis (fig. 601, F). In
venation the pinnae agree with those of Otozamites but the base is not
auriculate. Kurr’s Liassic species Pterophyllum oblongifolium[1497] included
by Schimper in Glossozamites is probably an Otozamites. Another species
referred to this genus is Schenk’s Podozamites Zitteli[1498] from the Urgonian
of Austria (fig. 601, F): in this species the slightly falcate pinnae with
obtuse apices have rounded and not auriculate bases and there is some
evidence of a basal callosity. This species agrees so closely with such a
typical Zamites as Z. gigas that it is difficult to see on what grounds the
retention of Glossozamites is desirable. A Portuguese specimen referred by
Page 578
Saporta[1499] to Glossozamites, G. brevis, is founded on a single specimen
very like a leaflet of Otozamites Klipsteinii (Dunk.); and G. parvifolia Yok.
[1500]
from China has no claim to be included among Cycadean fronds.
Feistmantel’s Glossozamites Stoliczkanus[1501] is almost certainly a leaf of
Cordaites. For certain fronds originally described as Zamites Zeiller[1502] has
instituted the genus Plagiozamites. An important question as to the type of
frond which may conveniently be included in the genus Zamites was raised
by the application of this name by Heer to some Lower Cretaceous fronds
from Greenland, Z. borealis (= Ptilophyllum boreale, fig. 597), and others
which differ in the form of the pinnae from species usually regarded as
typical of the genus. Halle[1503] accepts the Greenland species as examples of
Zamites though he distinguishes them by a sectional name Sub-Zamites; he
defines Zamites as including fronds with pinnae attached to the upper face
of the rachis with a contracted and always symmetrical base though in some
cases the basal contraction is exceedingly small; there is a more or less
distinct basal callosity. He recognises two types, (i) Eu-Zamites, e.g.
Zamites gigas (fig. 599), in which the pinnae are strongly contracted basally
and have a callosity, and (ii) Sub-Zamites, e.g. Z. borealis[1504], etc., in which
the pinnae are not so broadly rounded at the base and retain the same
breadth to the point of insertion where they are ‘very rapidly and very little
contracted,’ with or without a basal callosity. The basal callosity in these
forms is not shown in many of the pinnae and is at most but a slight
rounding of the angles of the truncate base. The specimens referred by
Halle to Sub-Zamites do not appear to differ in any feature worthy of
generic rank from Ptilophyllum.
In the following definition Zamites is employed in a sense more or less in
accordance with Brongniart’s usage but with the inclusion of such forms as
Z. Buchianus, the type of Nathorst’s Zamiophyllum, and the exclusion of
Heer’s Arctic and Halle’s Antarctic fronds referred by them to Zamites.
Fronds broadly lanceolate reaching a length of over 60 cm.; pinnae more
or less oblique or at right-angles to the rachis (fig. 599), attached to the
upper surface but not completely covering it, linear or linear-lanceolate,
acuminate or obtuse, usually abruptly contracted at the rounded base and
more rarely (e.g. Z. Buchianus, fig. 601) gradually tapering to the proximal
end, with or without a callosity at the symmetrical base; veins divergent at
the base, simple or dichotomously branched, for the most part parallel to the
very like a leaflet of Otozamites Klipsteinii (Dunk.); and G. parvifolia Yok.
[1500]
from China has no claim to be included among Cycadean fronds.
Feistmantel’s Glossozamites Stoliczkanus[1501] is almost certainly a leaf of
Cordaites. For certain fronds originally described as Zamites Zeiller[1502] has
instituted the genus Plagiozamites. An important question as to the type of
frond which may conveniently be included in the genus Zamites was raised
by the application of this name by Heer to some Lower Cretaceous fronds
from Greenland, Z. borealis (= Ptilophyllum boreale, fig. 597), and others
which differ in the form of the pinnae from species usually regarded as
typical of the genus. Halle[1503] accepts the Greenland species as examples of
Zamites though he distinguishes them by a sectional name Sub-Zamites; he
defines Zamites as including fronds with pinnae attached to the upper face
of the rachis with a contracted and always symmetrical base though in some
cases the basal contraction is exceedingly small; there is a more or less
distinct basal callosity. He recognises two types, (i) Eu-Zamites, e.g.
Zamites gigas (fig. 599), in which the pinnae are strongly contracted basally
and have a callosity, and (ii) Sub-Zamites, e.g. Z. borealis[1504], etc., in which
the pinnae are not so broadly rounded at the base and retain the same
breadth to the point of insertion where they are ‘very rapidly and very little
contracted,’ with or without a basal callosity. The basal callosity in these
forms is not shown in many of the pinnae and is at most but a slight
rounding of the angles of the truncate base. The specimens referred by
Halle to Sub-Zamites do not appear to differ in any feature worthy of
generic rank from Ptilophyllum.
In the following definition Zamites is employed in a sense more or less in
accordance with Brongniart’s usage but with the inclusion of such forms as
Z. Buchianus, the type of Nathorst’s Zamiophyllum, and the exclusion of
Heer’s Arctic and Halle’s Antarctic fronds referred by them to Zamites.
Fronds broadly lanceolate reaching a length of over 60 cm.; pinnae more
or less oblique or at right-angles to the rachis (fig. 599), attached to the
upper surface but not completely covering it, linear or linear-lanceolate,
acuminate or obtuse, usually abruptly contracted at the rounded base and
more rarely (e.g. Z. Buchianus, fig. 601) gradually tapering to the proximal
end, with or without a callosity at the symmetrical base; veins divergent at
the base, simple or dichotomously branched, for the most part parallel to the
Page 579
edges of the lamina and slightly divergent in the apical region. The presence
of a basal callosity, such as is best seen in the pinnae of recent species of
Macrozamia, is not a feature of great importance and cannot be easily
recognised in many impressions. In the process of fossilisation the pinnae
are often flattened against the surface of the rachis and this may produce
transverse wrinklings of the lamina suggestive of a basal thickening. In
some cases stems of the Bucklandia type occur in connexion with Zamites
fronds (fig. 541). An account of these stems, and of inflorescences of
Williamsonia which were borne by some at least of the plants with Zamites
leaves is given in Chapter xxviii. In such examples of Zamites as have been
examined the epidermal cells have sinuous walls and the stomata[1505],
confined to the lower face of the lamina, occur in rows with their long axis
at right-angles to that of the pinnae.
Zamites ranges from Rhaetic to Lower Cretaceous strata.
Zamites truncatus Zeiller.
A Rhaetic species from Tonkin[1506] characterised by oval linear pinnae
given off at a wide angle, alternate and not contiguous; apex obtusely
truncate, gradually narrowed to a cuneate base which is rounded or
elliptical and has a more or less definite callosity. The pinnae vary from 3 to
5 cm. in length and from 5 to 13 mm. in breadth.
Zamites gigas (Lindley and Hutton).
The specific name gigas is retained in preference to that of Mantelli
employed by Brongniart[1507] on the ground that he afterwards discarded it in
favour of the designation proposed by Lindley and Hutton[1508], and because
their name has been generally adopted.
Fronds large, exceeding 60 cm.; broadly linear lanceolate; the
comparatively slender rachis bears alternate linear lanceolate pinnae with a
rounded and usually slightly swollen base and an acuminate apex. At the
apex of the frond the pinnae are narrow and linear (fig. 599) and almost
parallel to the rachis; in the lower part they are shorter and relatively
broader and attached approximately at right-angles. The numerous veins
diverge from the centre of the base but for the most part are parallel to the
edge of the lamina. The form of the epidermal cells and the structure of the
of a basal callosity, such as is best seen in the pinnae of recent species of
Macrozamia, is not a feature of great importance and cannot be easily
recognised in many impressions. In the process of fossilisation the pinnae
are often flattened against the surface of the rachis and this may produce
transverse wrinklings of the lamina suggestive of a basal thickening. In
some cases stems of the Bucklandia type occur in connexion with Zamites
fronds (fig. 541). An account of these stems, and of inflorescences of
Williamsonia which were borne by some at least of the plants with Zamites
leaves is given in Chapter xxviii. In such examples of Zamites as have been
examined the epidermal cells have sinuous walls and the stomata[1505],
confined to the lower face of the lamina, occur in rows with their long axis
at right-angles to that of the pinnae.
Zamites ranges from Rhaetic to Lower Cretaceous strata.
Zamites truncatus Zeiller.
A Rhaetic species from Tonkin[1506] characterised by oval linear pinnae
given off at a wide angle, alternate and not contiguous; apex obtusely
truncate, gradually narrowed to a cuneate base which is rounded or
elliptical and has a more or less definite callosity. The pinnae vary from 3 to
5 cm. in length and from 5 to 13 mm. in breadth.
Zamites gigas (Lindley and Hutton).
The specific name gigas is retained in preference to that of Mantelli
employed by Brongniart[1507] on the ground that he afterwards discarded it in
favour of the designation proposed by Lindley and Hutton[1508], and because
their name has been generally adopted.
Fronds large, exceeding 60 cm.; broadly linear lanceolate; the
comparatively slender rachis bears alternate linear lanceolate pinnae with a
rounded and usually slightly swollen base and an acuminate apex. At the
apex of the frond the pinnae are narrow and linear (fig. 599) and almost
parallel to the rachis; in the lower part they are shorter and relatively
broader and attached approximately at right-angles. The numerous veins
diverge from the centre of the base but for the most part are parallel to the
edge of the lamina. The form of the epidermal cells and the structure of the
Page 580
stomata have recently been described by Mr Thomas. The external features
of the stem (fig. 541) are described under the genus Williamsonia. In the
case of fronds of this type from English Jurassic rocks it would be
legitimate to speak of them as Williamsonia gigas, but in view of the fact
that such fronds usually occur as detached specimens and without any
associated flowers it is advisable, as Nathorst maintains, to retain the non-
committal genus Zamites.
Fig. 599. Zamites gigas. (British Museum, V. 2723a; ½ nat. size.)
This type of frond is widely distributed in Jurassic strata. The occurrence
of many forms agreeing generally with the type-specimen but differing
of the stem (fig. 541) are described under the genus Williamsonia. In the
case of fronds of this type from English Jurassic rocks it would be
legitimate to speak of them as Williamsonia gigas, but in view of the fact
that such fronds usually occur as detached specimens and without any
associated flowers it is advisable, as Nathorst maintains, to retain the non-
committal genus Zamites.
Fig. 599. Zamites gigas. (British Museum, V. 2723a; ½ nat. size.)
This type of frond is widely distributed in Jurassic strata. The occurrence
of many forms agreeing generally with the type-specimen but differing
Page 581
from it in features that are not constant or of real morphological importance
renders accurate specific delimitation very difficult. Species that appear to
be indistinguishable from Zamites gigas by any well-marked characters are,
Zamites Feneonis[1509] Brongn., Z. Moreaui[1510] Brongn., Z. Renevieri[1511]
Heer, and Z. claravallensis[1512] Sap.; similarly Z. Schmiedelii And.[1513] is
probably identical with Z. gigas. The Lower Cretaceous species Zamites
bohemicus[1514] Vel. and Z. iburgensis[1515] Hos. and von d. Marck represent
very similar forms.
Zamites recta (Tate).
This species was originally described by Tate[1516] as
Palaeozamia (Otozamites) recta from Wealden strata in
South Africa and subsequently transferred to Zamites[1517];
it bears a very close resemblance to Z. gigas. The fronds
bear alternate linear pinnae attached to the upper face of
the rachis by a slightly contracted and swollen base. The
lamina has an acuminate asymmetrical apex and the upper
edge is slightly falcate; the larger pinnae are over 6 cm.
long and nearly 1 cm. broad; the veins are frequently
forked as they converge towards the base of the lamina.
No clear evidence of association of these fronds in the
Uitenhage series of South Africa with Williamsonia
flowers has been discovered, but a specimen[1518] in the
Tate collection in the British Museum may be a badly
preserved cluster of bracts belonging to a Williamsonia.
The rachis of this species shows some peculiar features in
the form of two rows of alternate cushions in some
partially decayed specimens. One of these is shown in fig.
600; the cushions are raised oval projections with a flat
top, and pieces of the rachis without pinnae might easily Fig. 600.
be mistaken for a Coniferous stem. Zamites recta.
(Uitenhage
Zamites Carruthersi Seward. series, S.
Africa.)
A species founded on specimens from the Wealden of
Sussex[1519] and recorded from Kimmeridge beds in Scotland[1520],
characterised by linear or linear-elliptical pinnae attached obliquely to the
renders accurate specific delimitation very difficult. Species that appear to
be indistinguishable from Zamites gigas by any well-marked characters are,
Zamites Feneonis[1509] Brongn., Z. Moreaui[1510] Brongn., Z. Renevieri[1511]
Heer, and Z. claravallensis[1512] Sap.; similarly Z. Schmiedelii And.[1513] is
probably identical with Z. gigas. The Lower Cretaceous species Zamites
bohemicus[1514] Vel. and Z. iburgensis[1515] Hos. and von d. Marck represent
very similar forms.
Zamites recta (Tate).
This species was originally described by Tate[1516] as
Palaeozamia (Otozamites) recta from Wealden strata in
South Africa and subsequently transferred to Zamites[1517];
it bears a very close resemblance to Z. gigas. The fronds
bear alternate linear pinnae attached to the upper face of
the rachis by a slightly contracted and swollen base. The
lamina has an acuminate asymmetrical apex and the upper
edge is slightly falcate; the larger pinnae are over 6 cm.
long and nearly 1 cm. broad; the veins are frequently
forked as they converge towards the base of the lamina.
No clear evidence of association of these fronds in the
Uitenhage series of South Africa with Williamsonia
flowers has been discovered, but a specimen[1518] in the
Tate collection in the British Museum may be a badly
preserved cluster of bracts belonging to a Williamsonia.
The rachis of this species shows some peculiar features in
the form of two rows of alternate cushions in some
partially decayed specimens. One of these is shown in fig.
600; the cushions are raised oval projections with a flat
top, and pieces of the rachis without pinnae might easily Fig. 600.
be mistaken for a Coniferous stem. Zamites recta.
(Uitenhage
Zamites Carruthersi Seward. series, S.
Africa.)
A species founded on specimens from the Wealden of
Sussex[1519] and recorded from Kimmeridge beds in Scotland[1520],
characterised by linear or linear-elliptical pinnae attached obliquely to the
Page 582
outer part of the upper surface of the rachis, somewhat abruptly narrowed at
the proximal end but slightly broadened at the actual base (fig. 601, D, E).
The pinnae appear to have been caducous and, as in fig. 601, D, the position
of an absciss-layer is occasionally visible. In habit the fronds bear a close
resemblance to those of Encephalartos longifolius Lehm. The veins diverge
from the base and are for the most part parallel, though divergent at the
bluntly rounded apex. If, as may be the case, a specimen figured by Hugh
Miller[1521] from Scotland as Zamites and subsequently named by
Richards[1522] Podozamites Milleri is identical with Z. Carruthersi, the
specific name Milleri has priority.
the proximal end but slightly broadened at the actual base (fig. 601, D, E).
The pinnae appear to have been caducous and, as in fig. 601, D, the position
of an absciss-layer is occasionally visible. In habit the fronds bear a close
resemblance to those of Encephalartos longifolius Lehm. The veins diverge
from the base and are for the most part parallel, though divergent at the
bluntly rounded apex. If, as may be the case, a specimen figured by Hugh
Miller[1521] from Scotland as Zamites and subsequently named by
Richards[1522] Podozamites Milleri is identical with Z. Carruthersi, the
specific name Milleri has priority.
Page 583
Fig. 601. A–C, Zamites Buchianus. D, E, Zamites Carruthersi. F, Zamites
Zitteli. (A–C after Seward; British Museum; A, V. 2363; B, V.
2123a; C, V. 2227; F, after Schenk.)
Zamites Buchianus (Ettingshausen).
A Wealden and Lower Cretaceous species[1523] (figs. 601, A–C; 602)
represented in several European localities, also in North America and Japan,
reaching a length of over 70 cm.; in habit very similar to Ceratozamia
mexicana, Macrozamia Macleayi and some other recent Cycads. The rachis
Zitteli. (A–C after Seward; British Museum; A, V. 2363; B, V.
2123a; C, V. 2227; F, after Schenk.)
Zamites Buchianus (Ettingshausen).
A Wealden and Lower Cretaceous species[1523] (figs. 601, A–C; 602)
represented in several European localities, also in North America and Japan,
reaching a length of over 70 cm.; in habit very similar to Ceratozamia
mexicana, Macrozamia Macleayi and some other recent Cycads. The rachis
Page 584
has a fairly broad median groove on the upper
surface; pinnae alternate, opposite or sub-
opposite, from 3 to 20 cm. long and from 1·5 to
2 cm. broad, linear, generally narrowed towards
the base, but in the more slender segments the
reduction in breadth is less obvious; attached
obliquely to the rachis, slightly thickened and
broadened at the base (fig. 601, C), separated
from the rachis by a distinct absciss-layer and
leaving an elliptical scar; usually inclined at
about 45° but the angle varies considerably in
different parts of a frond (fig. 602); apices
generally tapering to a point, or more or less
obtusely rounded; veins numerous, parallel, and
not as a rule prominent. It is by no means
unlikely that specimens figured by Goeppert[1524]
and some other authors as Pterophyllum
saxonicum or Dioonites saxonicus are examples
of this species. Fontaine[1525] speaks of Dioonites
Buchianus as one of the most widely distributed
and characteristic members of the Potomac flora
and it is described from Japan by Yokoyama[1526]
and Nathorst[1527]. This type appears to be
especially characteristic of Wealden strata.
OTOZAMITES. Braun.
Braun[1528] proposed the name Otozamites for
certain Mesozoic fronds formerly included in
Zamites, one of his types being Otozamites
Fig. 602. Zamites
obtusus (Lind. and Hutt.) (fig. 603, B) originally
Buchianus. (British
regarded by Brongniart as a Fern and named
Filicites Bucklandi[1529]. The auriculate form of Museum, V. 2120; ⅙
the base of the pinnae and the spreading veins nat. size.)
were emphasised in the definition of the genus. As in the case of many other
Cycadean fronds the limits of the genus are not always easy to define, but
as described below the genus is on the whole fairly distinctive. It is a very
widely spread Jurassic type and extends from Triassic to Lower Cretaceous
surface; pinnae alternate, opposite or sub-
opposite, from 3 to 20 cm. long and from 1·5 to
2 cm. broad, linear, generally narrowed towards
the base, but in the more slender segments the
reduction in breadth is less obvious; attached
obliquely to the rachis, slightly thickened and
broadened at the base (fig. 601, C), separated
from the rachis by a distinct absciss-layer and
leaving an elliptical scar; usually inclined at
about 45° but the angle varies considerably in
different parts of a frond (fig. 602); apices
generally tapering to a point, or more or less
obtusely rounded; veins numerous, parallel, and
not as a rule prominent. It is by no means
unlikely that specimens figured by Goeppert[1524]
and some other authors as Pterophyllum
saxonicum or Dioonites saxonicus are examples
of this species. Fontaine[1525] speaks of Dioonites
Buchianus as one of the most widely distributed
and characteristic members of the Potomac flora
and it is described from Japan by Yokoyama[1526]
and Nathorst[1527]. This type appears to be
especially characteristic of Wealden strata.
OTOZAMITES. Braun.
Braun[1528] proposed the name Otozamites for
certain Mesozoic fronds formerly included in
Zamites, one of his types being Otozamites
Fig. 602. Zamites
obtusus (Lind. and Hutt.) (fig. 603, B) originally
Buchianus. (British
regarded by Brongniart as a Fern and named
Filicites Bucklandi[1529]. The auriculate form of Museum, V. 2120; ⅙
the base of the pinnae and the spreading veins nat. size.)
were emphasised in the definition of the genus. As in the case of many other
Cycadean fronds the limits of the genus are not always easy to define, but
as described below the genus is on the whole fairly distinctive. It is a very
widely spread Jurassic type and extends from Triassic to Lower Cretaceous
Page 585
rocks. The supposed Cretaceous species from Greenland, O. groenlandica
Heer[1530], is probably not a plant-impression but a polished groove in the
rock.
Fronds pinnate, reaching a length of 50 cm. or more in some species;
pinnae alternate, separate or contiguous and imbricate, attached by a portion
of the base to the upper surface of the rachis, long and narrow (fig. 603, A),
broadly oval or almost orbicular, apex acute or obtuse, base auriculate and
asymmetrical[1531], the anterior lobe being more prominent than the posterior
edge of the lamina which is usually rounded. The veins radiate from the
base and pass obliquely with occasional branching to the edge of the pinna;
in the more linear pinnae the veins may be parallel or nearly so. Zigno[1532]
figured a piece of an Otozamites frond from Jurassic Italian strata in
connexion with a Williamsonia and the actual specimen in the Padua
Museum amply justifies the impression produced by the published drawing.
Wieland’s investigations[1533] in Mexico have brought to light many cases of
association of Otozamites fronds and Williamsonia flowers.
Heer[1530], is probably not a plant-impression but a polished groove in the
rock.
Fronds pinnate, reaching a length of 50 cm. or more in some species;
pinnae alternate, separate or contiguous and imbricate, attached by a portion
of the base to the upper surface of the rachis, long and narrow (fig. 603, A),
broadly oval or almost orbicular, apex acute or obtuse, base auriculate and
asymmetrical[1531], the anterior lobe being more prominent than the posterior
edge of the lamina which is usually rounded. The veins radiate from the
base and pass obliquely with occasional branching to the edge of the pinna;
in the more linear pinnae the veins may be parallel or nearly so. Zigno[1532]
figured a piece of an Otozamites frond from Jurassic Italian strata in
connexion with a Williamsonia and the actual specimen in the Padua
Museum amply justifies the impression produced by the published drawing.
Wieland’s investigations[1533] in Mexico have brought to light many cases of
association of Otozamites fronds and Williamsonia flowers.
Page 586
Fig. 603. A, Otozamites Goeppertianus. B, Otozamites obtusus (= O.
Bechei); type-specimen. (A, British Museum, V. 2360; B, Oxford
Museum.)
The structure of the epidermis is partially described by Schenk[1534] and
more fully by Thomas[1535]: the epidermal cells have sinuous walls and the
stomata, apparently confined to the lower surface, have guard-cells with
hemispherical or spindle-shaped thickened patches like those of some
Zamites fronds. In one species, O. Feistmanteli Zig., Thomas found about
100 stomata in 1 sq. mm. of lamina forming almost contiguous lines
between the veins. In the account of the genus Ptilophyllum reference is
made to the occurrence of pinnae with asymmetrical and auriculate bases,
and it is only by the comparison of a large number of specimens that a
Bechei); type-specimen. (A, British Museum, V. 2360; B, Oxford
Museum.)
The structure of the epidermis is partially described by Schenk[1534] and
more fully by Thomas[1535]: the epidermal cells have sinuous walls and the
stomata, apparently confined to the lower surface, have guard-cells with
hemispherical or spindle-shaped thickened patches like those of some
Zamites fronds. In one species, O. Feistmanteli Zig., Thomas found about
100 stomata in 1 sq. mm. of lamina forming almost contiguous lines
between the veins. In the account of the genus Ptilophyllum reference is
made to the occurrence of pinnae with asymmetrical and auriculate bases,
and it is only by the comparison of a large number of specimens that a
Page 587
distinction can be drawn between fronds that should be assigned to
Otozamites and forms of Ptilophyllum which exhibit a well-marked
tendency towards the Otozamites type of pinna (cf. figs. 592, 593). The
variation in the form of the apices of pinnae and the relative position of the
pinnae in different parts of the same frond are features worthy of notice in
the determination of species[1536]. The different appearance presented by an
Otozamites frond as viewed from the upper and lower face is illustrated in
fig. 604. There are no recent Cycads in which the segments have auriculate
bases, but in this feature as in the sinuous epidermal walls Otozamites
agrees with some species of the Fern Aneimia, e.g. A. rotundifolia Schrad.
(fig. 223, Vol. ii. p. 288).
Fig. 604. Otozamites Bechei. A specimen in the Bristol Museum seen
from below (A) and above (B). M. S.
Otozamites Bechei Brongniart.
There is considerable confusion in the nomenclature of this species
described by Brongniart[1537] from Jurassic strata as Filicites Bechei: in it
Brongniart included a specimen from the Lias of Axminster (Dorsetshire)
previously figured by De la Beche as a fossil Fern. It was on the Axminster
specimen that Lindley and Hutton founded the species Otopteris obtusa[1538],
and as there is no doubt as to the specific identity of their type-specimen
(fig. 603, B) and De la Beche’s fossil, Brongniart’s designation has prior
claim[1539]. Otozamites Bechei is, perhaps, best regarded as a comprehensive
type or a group-species in which numerous Otozamites fronds described by
authors, on inadequate grounds, as distinct species may well be included.
Otozamites and forms of Ptilophyllum which exhibit a well-marked
tendency towards the Otozamites type of pinna (cf. figs. 592, 593). The
variation in the form of the apices of pinnae and the relative position of the
pinnae in different parts of the same frond are features worthy of notice in
the determination of species[1536]. The different appearance presented by an
Otozamites frond as viewed from the upper and lower face is illustrated in
fig. 604. There are no recent Cycads in which the segments have auriculate
bases, but in this feature as in the sinuous epidermal walls Otozamites
agrees with some species of the Fern Aneimia, e.g. A. rotundifolia Schrad.
(fig. 223, Vol. ii. p. 288).
Fig. 604. Otozamites Bechei. A specimen in the Bristol Museum seen
from below (A) and above (B). M. S.
Otozamites Bechei Brongniart.
There is considerable confusion in the nomenclature of this species
described by Brongniart[1537] from Jurassic strata as Filicites Bechei: in it
Brongniart included a specimen from the Lias of Axminster (Dorsetshire)
previously figured by De la Beche as a fossil Fern. It was on the Axminster
specimen that Lindley and Hutton founded the species Otopteris obtusa[1538],
and as there is no doubt as to the specific identity of their type-specimen
(fig. 603, B) and De la Beche’s fossil, Brongniart’s designation has prior
claim[1539]. Otozamites Bechei is, perhaps, best regarded as a comprehensive
type or a group-species in which numerous Otozamites fronds described by
authors, on inadequate grounds, as distinct species may well be included.
Page 588
Fronds agreeing generally with O. Bechei were very widely spread in
Rhaetic and Jurassic floras.
Specimens from the Middle Jurassic rocks of Yorkshire have been
described as Otozamites obtusus var. ooliticus[1540] to denote a slight
difference in the form of the pinnae from the Liassic fronds from
Dorsetshire; but the distinctive features of the variety ooliticus are
unimportant and hardly worthy of consideration in a general account of the
species interpreted in a wide sense.
Fronds pinnate; pinnae usually more or less falcate, occasionally straight
and with parallel sides, attached obliquely to the upper side of the rachis;
imbricate or separate, the upper edge of the base of the lamina strongly
auriculate, the lower edge rounded; apex obtuse; veins strongly divergent
especially in the lobed base and extending obliquely to the upper and lower
edge of the lamina.
The specimen, from the Lias of Lyme Regis, drawn in outline in fig. 605,
is an almost perfect frond: the pinnae are obtusely pointed, slightly falcate,
and there is a prominent lobe on the upper edge of the base of the laminae.
The Jurassic species Otozamites graphicus[1541] (Leck. ex Bean ms.), O.
vicetinus Zig.[1542], O. Hennocquei[1543] (Pom.), O. recurrens Sap., O.
Terquemi[1544] Sap., O. linearis[1545] Halle, are some of many examples of
fronds agreeing closely with O. Bechei, or in the case of O. Terquemi with
O. graphicus. The fronds described by Halle from Graham Land as O.
linearis afford a good illustration of the range of variation in the pinnae: a
characteristic feature is the considerable length, exceeding 20 cm., of the
narrow linear fronds. The impressions from the Kome (Cretaceous) beds of
Greenland described by Heer as Glossozamites Schenkii[1546] are probably
closely allied to O. Bechei. The Rhaetic species O. Bucklandi Schenk[1547],
O. indosinensis Zeill.[1548], and O. Polakii Krass[1549], illustrate older
examples of closely allied types. Zeiller records Otozamites pinnae similar
to those of O. indosinensis from Rhaetic beds in Persia[1550].
Otozamites Beani (Lindley and Hutton).
Founded on a specimen in the Scarborough Museum from the Middle
Jurassic of Yorkshire[1551] which is indistinguishable from Leckenby’s type-
specimen of Otopteris mediana[1552] in the Sedgwick Museum, Cambridge.
Rhaetic and Jurassic floras.
Specimens from the Middle Jurassic rocks of Yorkshire have been
described as Otozamites obtusus var. ooliticus[1540] to denote a slight
difference in the form of the pinnae from the Liassic fronds from
Dorsetshire; but the distinctive features of the variety ooliticus are
unimportant and hardly worthy of consideration in a general account of the
species interpreted in a wide sense.
Fronds pinnate; pinnae usually more or less falcate, occasionally straight
and with parallel sides, attached obliquely to the upper side of the rachis;
imbricate or separate, the upper edge of the base of the lamina strongly
auriculate, the lower edge rounded; apex obtuse; veins strongly divergent
especially in the lobed base and extending obliquely to the upper and lower
edge of the lamina.
The specimen, from the Lias of Lyme Regis, drawn in outline in fig. 605,
is an almost perfect frond: the pinnae are obtusely pointed, slightly falcate,
and there is a prominent lobe on the upper edge of the base of the laminae.
The Jurassic species Otozamites graphicus[1541] (Leck. ex Bean ms.), O.
vicetinus Zig.[1542], O. Hennocquei[1543] (Pom.), O. recurrens Sap., O.
Terquemi[1544] Sap., O. linearis[1545] Halle, are some of many examples of
fronds agreeing closely with O. Bechei, or in the case of O. Terquemi with
O. graphicus. The fronds described by Halle from Graham Land as O.
linearis afford a good illustration of the range of variation in the pinnae: a
characteristic feature is the considerable length, exceeding 20 cm., of the
narrow linear fronds. The impressions from the Kome (Cretaceous) beds of
Greenland described by Heer as Glossozamites Schenkii[1546] are probably
closely allied to O. Bechei. The Rhaetic species O. Bucklandi Schenk[1547],
O. indosinensis Zeill.[1548], and O. Polakii Krass[1549], illustrate older
examples of closely allied types. Zeiller records Otozamites pinnae similar
to those of O. indosinensis from Rhaetic beds in Persia[1550].
Otozamites Beani (Lindley and Hutton).
Founded on a specimen in the Scarborough Museum from the Middle
Jurassic of Yorkshire[1551] which is indistinguishable from Leckenby’s type-
specimen of Otopteris mediana[1552] in the Sedgwick Museum, Cambridge.
Page 589
Long and narrow fronds exceeding 20 cm. in length,
characterised by the broadly oval, deltoid or sub-orbicular
pinnae, separate or partially imbricate and attached by a
broad auriculate base; apex bluntly rounded; veins
numerous and spreading from the base of the lamina. The
pinnae, which may be 3·5 cm. long and nearly 2 cm.
broad, are narrower and longer in the distal part of the
frond (fig. 606).
The Italian Jurassic species Otozamites molianus Zig.
[1553]
, recorded also from Bornholm, is a very similar type.
The generic name Cyclozamia suggested by Pomel for
this form of frond has not been adopted though it is
applied by Schimper to O. Bunburyanus Zig.
Otozamites Bunburyanus Zigno.
A Jurassic species[1554] similar in the long and narrow
form of the frond to O. Beani but distinguished by the
much smaller segments and by their more orbicular
lamina (fig. 606, B). In habit the fronds agree closely with
the Fern Nephrolepis Duffi. Leckenby’s species, Otopteris
tenuata[1555], is probably the same as Zigno’s O.
Bunburyanus, the type-specimen of which in the Padua
Museum consists of a long and narrow frond with leaflets
not exceeding 8 cm. in length; the rachis is hidden by the
imbricate auriculate bases of the leaflets. Feistmantel[1556]
refers to this species some pieces of very narrow fronds Fig. 605.
with overlapping pinnae from Upper Gondwana beds in Otozamites
India. A still smaller form is described by Möller[1557] from Bechei.
Bornholm as O. tenuissimus, and O. Bunburyanus is (British
recorded from the same flora. O. Feistmanteli Zig.[1558] Museum,
agrees in the form of the frond and in its short and broad 40672; ⅔ nat.
pinnae with O. Bunburyanus. size.)
characterised by the broadly oval, deltoid or sub-orbicular
pinnae, separate or partially imbricate and attached by a
broad auriculate base; apex bluntly rounded; veins
numerous and spreading from the base of the lamina. The
pinnae, which may be 3·5 cm. long and nearly 2 cm.
broad, are narrower and longer in the distal part of the
frond (fig. 606).
The Italian Jurassic species Otozamites molianus Zig.
[1553]
, recorded also from Bornholm, is a very similar type.
The generic name Cyclozamia suggested by Pomel for
this form of frond has not been adopted though it is
applied by Schimper to O. Bunburyanus Zig.
Otozamites Bunburyanus Zigno.
A Jurassic species[1554] similar in the long and narrow
form of the frond to O. Beani but distinguished by the
much smaller segments and by their more orbicular
lamina (fig. 606, B). In habit the fronds agree closely with
the Fern Nephrolepis Duffi. Leckenby’s species, Otopteris
tenuata[1555], is probably the same as Zigno’s O.
Bunburyanus, the type-specimen of which in the Padua
Museum consists of a long and narrow frond with leaflets
not exceeding 8 cm. in length; the rachis is hidden by the
imbricate auriculate bases of the leaflets. Feistmantel[1556]
refers to this species some pieces of very narrow fronds Fig. 605.
with overlapping pinnae from Upper Gondwana beds in Otozamites
India. A still smaller form is described by Möller[1557] from Bechei.
Bornholm as O. tenuissimus, and O. Bunburyanus is (British
recorded from the same flora. O. Feistmanteli Zig.[1558] Museum,
agrees in the form of the frond and in its short and broad 40672; ⅔ nat.
pinnae with O. Bunburyanus. size.)
Page 590
Fig. 606. A, Otozamites Beani. B,
Otozamites Bunburyanus.
Fig. 607. Otozamites bengalensis.
(Indian Geological Survey,
Calcutta; ⅔ nat. size.)
Otozamites bengalensis (Oldham and Morris).
This Indian species from the Rajmahal Hills[1559] and specimens of the
same type from the Cutch flora described as O. contiguus Feist. afford
another illustration of long and narrow fronds with short and relatively
broad pinnae. The drawings published by Oldham and Morris accurately
represent the specimens: the longest frond is 21 cm. long and neither end is
complete (fig. 607); it is 9 mm. broad at the narrower end and 1·5 cm. at the
broader end. The rachis is represented by a deep and broad groove; the
Otozamites Bunburyanus.
Fig. 607. Otozamites bengalensis.
(Indian Geological Survey,
Calcutta; ⅔ nat. size.)
Otozamites bengalensis (Oldham and Morris).
This Indian species from the Rajmahal Hills[1559] and specimens of the
same type from the Cutch flora described as O. contiguus Feist. afford
another illustration of long and narrow fronds with short and relatively
broad pinnae. The drawings published by Oldham and Morris accurately
represent the specimens: the longest frond is 21 cm. long and neither end is
complete (fig. 607); it is 9 mm. broad at the narrower end and 1·5 cm. at the
broader end. The rachis is represented by a deep and broad groove; the
Page 591
actual bases of the leaflets are not preserved, but their position shows that
they were attached to the upper face: this is clearly seen in the specimen
described by Feistmantel as O. contiguus which shows also that the lamina
is auriculate at the upper edge of the base. The pinnae vary in shape; the
smaller ones are characterised by a strongly curved lower margin and the
upper edge is slightly curved or straight, while the larger leaflets have more
parallel edges and blunter rounded apices: the latter form is well shown in
the specimens unnecessarily distinguished by Oldham and Morris as var.
obtusa.
Otozamites Klipsteinii (Dunker).
This Wealden species, first described by Dunker as Cyclopteris
Klipsteinii[1560], is remarkable for the large pinnae. The rachis is fairly stout;
the broadly oval or oblong pinnae vary considerably in size and in the
relation of breadth to length, in rare cases reaching a length of over 8 cm.
and a breadth of 2·4 cm.; apex obtuse, base slightly auriculate and
asymmetrical; veins numerous, radiating from the point of attachment to the
margin of the lamina. The occurrence of finer lines between the more
prominent veins may indicate the presence of hypodermal stereome strands.
Fig. 608 illustrates the striking variation in the size of the pinnae on a single
frond and their attachment to the upper face of the rachis. In the breadth of
the segments O. Klipsteinii resembles O. Beani (Lind. and Hutt.), O.
decorus Sap.[1561], O. lagotis Brongn.[1562] and two species from South Russia
described by Thomas[1563] as O. Izuimensis and O. giganteus. The pinnae of
O. giganteus exceed 10 cm. in length and 3 cm. in breadth, thus surpassing
the largest segments of O. Klipsteinii. Some pinnae from the Jurassic flora
of Oregon made by Fontaine the type of a new species, O. oregonensis[1564],
may be fragments of O. Klipsteinii. Nathorst[1565] records the occurrence in
Lower Cretaceous or Wealden beds in Spitzbergen of Cycadean leaflets
very like those of O. Klipsteinii.
Otozamites Goeppertianus (Dunker).
This Wealden species, named by Dunker[1566] Pterophyllum
Goeppertianum, agrees in habit with some of those to which reference is
made under O. Bechei, e.g. O. linearis Halle, and represents a type of the
genus with unusually narrow pinnae (fig. 603, A). The auriculate form of
they were attached to the upper face: this is clearly seen in the specimen
described by Feistmantel as O. contiguus which shows also that the lamina
is auriculate at the upper edge of the base. The pinnae vary in shape; the
smaller ones are characterised by a strongly curved lower margin and the
upper edge is slightly curved or straight, while the larger leaflets have more
parallel edges and blunter rounded apices: the latter form is well shown in
the specimens unnecessarily distinguished by Oldham and Morris as var.
obtusa.
Otozamites Klipsteinii (Dunker).
This Wealden species, first described by Dunker as Cyclopteris
Klipsteinii[1560], is remarkable for the large pinnae. The rachis is fairly stout;
the broadly oval or oblong pinnae vary considerably in size and in the
relation of breadth to length, in rare cases reaching a length of over 8 cm.
and a breadth of 2·4 cm.; apex obtuse, base slightly auriculate and
asymmetrical; veins numerous, radiating from the point of attachment to the
margin of the lamina. The occurrence of finer lines between the more
prominent veins may indicate the presence of hypodermal stereome strands.
Fig. 608 illustrates the striking variation in the size of the pinnae on a single
frond and their attachment to the upper face of the rachis. In the breadth of
the segments O. Klipsteinii resembles O. Beani (Lind. and Hutt.), O.
decorus Sap.[1561], O. lagotis Brongn.[1562] and two species from South Russia
described by Thomas[1563] as O. Izuimensis and O. giganteus. The pinnae of
O. giganteus exceed 10 cm. in length and 3 cm. in breadth, thus surpassing
the largest segments of O. Klipsteinii. Some pinnae from the Jurassic flora
of Oregon made by Fontaine the type of a new species, O. oregonensis[1564],
may be fragments of O. Klipsteinii. Nathorst[1565] records the occurrence in
Lower Cretaceous or Wealden beds in Spitzbergen of Cycadean leaflets
very like those of O. Klipsteinii.
Otozamites Goeppertianus (Dunker).
This Wealden species, named by Dunker[1566] Pterophyllum
Goeppertianum, agrees in habit with some of those to which reference is
made under O. Bechei, e.g. O. linearis Halle, and represents a type of the
genus with unusually narrow pinnae (fig. 603, A). The auriculate form of
Page 592
the lamina is feebly developed; the linear-lanceolate pinnae are occasionally
falcate and have acute apices; as in many other species they were
apparently deciduous. It is by no means easy to distinguish some of these
fronds from specimens included in Ptilophyllum pecten.
Fig. 608. Otozamites Kliptsteini. (British Museum, V. 3709; nat. size.)
DICTYOZAMITES. Oldham.
This generic name was instituted[1567] for pinnate fronds from the
Rajmahal series of India, assigned by Feistmantel to a Lower Jurassic
falcate and have acute apices; as in many other species they were
apparently deciduous. It is by no means easy to distinguish some of these
fronds from specimens included in Ptilophyllum pecten.
Fig. 608. Otozamites Kliptsteini. (British Museum, V. 3709; nat. size.)
DICTYOZAMITES. Oldham.
This generic name was instituted[1567] for pinnate fronds from the
Rajmahal series of India, assigned by Feistmantel to a Lower Jurassic
Page 593
horizon, but probably nearer in age to the Middle Jurassic series. Morris,
joint author with Oldham of the Memoir on the Rajmahal plants, adopted
the name Dictyopteris. Dictyozamites agrees very closely with Otozamites
but is readily distinguished by the anastomosing veins (fig. 609), while the
absence of a midrib differentiates it from the Palaeozoic genus Dictyopteris.
The genus is recorded also from Jurassic strata in England, Bornholm,
Japan[1568], Korea[1569], and from a locality 60 nautical miles N.W. of Cape
Horn in Tierra del Fuego[1570]: the specimens from these localities differ only
in unimportant details from the Indian type. Dictyozamites is confined to
Jurassic floras and appears to be especially characteristic of Middle Jurassic
floras. In India[1571] fronds occur in close association with stems of the
Bucklandia type and, although there is no proof of any connexion with
stems or flowers, it is probable that the fronds of this generic type were
borne on stems similar to those of Bucklandia and that the flowers were
constructed on the Williamsonia plan.
Dictyozamites falcatus (Morris).
Morris[1572] described this Rajmahal species under the names Dictyopteris
falcata and D. falcata var. obtusa; the specimens were included by
Feistmantel under the designation Dictyozamites indicus, the original term
falcata being discarded without adequate reason. An examination of several
of the figured fronds enables me to confirm the accuracy of the published
drawings and to extend the description in a few particulars. Fronds pinnate
of the habit of Otozamites; pinnae comparatively thick, broadly linear,
alternate, varying considerably in size and in the form of the apex which
may be obtuse or acute. The pinnae are attached by the middle part of the
lamina only; the upper edge of the base is slightly rounded or auriculate; the
lower angle is generally more definitely lobed. The imbricate bases
completely cover the upper face of the comparatively slender rachis. The
longest pinna seen on an Indian frond is 6 cm. with a breadth of 2 cm. Some
of the pinnae on magnification exhibit a finely tuberculate appearance, due
no doubt to the presence of papillae on the epidermal cells like those on the
pinnae of English and Bornholm specimens. This species is recorded by
Yokoyama[1573] from Japan as D. falcatus var. distans, and a similar form,
referred by him to a distinct species, D. grossinervis, may be more
appropriately named D. falcatus var. grossinervis[1574]. The Indian type
occurs also in Jurassic rocks of Korea, and Halle has discovered some
joint author with Oldham of the Memoir on the Rajmahal plants, adopted
the name Dictyopteris. Dictyozamites agrees very closely with Otozamites
but is readily distinguished by the anastomosing veins (fig. 609), while the
absence of a midrib differentiates it from the Palaeozoic genus Dictyopteris.
The genus is recorded also from Jurassic strata in England, Bornholm,
Japan[1568], Korea[1569], and from a locality 60 nautical miles N.W. of Cape
Horn in Tierra del Fuego[1570]: the specimens from these localities differ only
in unimportant details from the Indian type. Dictyozamites is confined to
Jurassic floras and appears to be especially characteristic of Middle Jurassic
floras. In India[1571] fronds occur in close association with stems of the
Bucklandia type and, although there is no proof of any connexion with
stems or flowers, it is probable that the fronds of this generic type were
borne on stems similar to those of Bucklandia and that the flowers were
constructed on the Williamsonia plan.
Dictyozamites falcatus (Morris).
Morris[1572] described this Rajmahal species under the names Dictyopteris
falcata and D. falcata var. obtusa; the specimens were included by
Feistmantel under the designation Dictyozamites indicus, the original term
falcata being discarded without adequate reason. An examination of several
of the figured fronds enables me to confirm the accuracy of the published
drawings and to extend the description in a few particulars. Fronds pinnate
of the habit of Otozamites; pinnae comparatively thick, broadly linear,
alternate, varying considerably in size and in the form of the apex which
may be obtuse or acute. The pinnae are attached by the middle part of the
lamina only; the upper edge of the base is slightly rounded or auriculate; the
lower angle is generally more definitely lobed. The imbricate bases
completely cover the upper face of the comparatively slender rachis. The
longest pinna seen on an Indian frond is 6 cm. with a breadth of 2 cm. Some
of the pinnae on magnification exhibit a finely tuberculate appearance, due
no doubt to the presence of papillae on the epidermal cells like those on the
pinnae of English and Bornholm specimens. This species is recorded by
Yokoyama[1573] from Japan as D. falcatus var. distans, and a similar form,
referred by him to a distinct species, D. grossinervis, may be more
appropriately named D. falcatus var. grossinervis[1574]. The Indian type
occurs also in Jurassic rocks of Korea, and Halle has discovered some
Page 594
Dictyozamites leaves in Tierra del Fuego[1575] which he describes as
Dictyozamites sp. cf. D. falcatus: this record is of special interest from a
phytogeographical point of view.
Dictyozamites Johnstrupi Nathorst.
This species[1576], from rocks usually spoken of as Liassic but not
improbably Middle Jurassic in age, differs from D. falcatus in the slightly
more falcate form of the pinnae and in the more strongly auriculate upper
angle of the base of the lamina. The stomata[1577] are confined to the lower
epidermis and the strongly cuticularised guard-cells frequently lie at right-
angles to the course of the veins. The epidermal cells have very sinuous
walls (fig. 609, C) and in the middle of each is a prominent papilla.
Dictyozamites Hawelli Seward.
This Middle Jurassic type from Marske[1578], Yorkshire, differs from D.
falcatus in the relatively broader segments, their straighter form (fig. 609,
B), and in the attachment to the rachis being slightly below the middle of
the pinna base. Fig. 609, A, shows the base of a pinna and an oval scar
similar to those on the rachis of some recent Cycads (cf. fig. 387). The
epidermis is like that in D. Johnstrupi and as in that species the stomata are
confined to the lower surface. There are approximately 120 stomata per
square millimetre; each with two subsidiary cells (fig. 609, C) of elongated
form, and the guard-cells have small thickened outgrowths or papillae as in
D. Johnstrupi.
The epidermal features are described under D. Johnstrupi and D. Hawelli
(fig. 609, C): a fuller account of those in the latter species will be found in
the paper by Mr Thomas and Miss Bancroft.
Dictyozamites sp. cf. D. falcatus: this record is of special interest from a
phytogeographical point of view.
Dictyozamites Johnstrupi Nathorst.
This species[1576], from rocks usually spoken of as Liassic but not
improbably Middle Jurassic in age, differs from D. falcatus in the slightly
more falcate form of the pinnae and in the more strongly auriculate upper
angle of the base of the lamina. The stomata[1577] are confined to the lower
epidermis and the strongly cuticularised guard-cells frequently lie at right-
angles to the course of the veins. The epidermal cells have very sinuous
walls (fig. 609, C) and in the middle of each is a prominent papilla.
Dictyozamites Hawelli Seward.
This Middle Jurassic type from Marske[1578], Yorkshire, differs from D.
falcatus in the relatively broader segments, their straighter form (fig. 609,
B), and in the attachment to the rachis being slightly below the middle of
the pinna base. Fig. 609, A, shows the base of a pinna and an oval scar
similar to those on the rachis of some recent Cycads (cf. fig. 387). The
epidermis is like that in D. Johnstrupi and as in that species the stomata are
confined to the lower surface. There are approximately 120 stomata per
square millimetre; each with two subsidiary cells (fig. 609, C) of elongated
form, and the guard-cells have small thickened outgrowths or papillae as in
D. Johnstrupi.
The epidermal features are described under D. Johnstrupi and D. Hawelli
(fig. 609, C): a fuller account of those in the latter species will be found in
the paper by Mr Thomas and Miss Bancroft.
Page 595
Fig. 609. Dictyozamites Hawelli. (A, B, British Museum; C, after
Thomas and Bancroft.)
PTEROPHYLLUM. Brongniart.
The name Pterophyllum was first applied by Brongniart[1579] to some
fronds from the Lias of Höör, which he named P. majus and P. minus,
species subsequently removed by Nathorst[1580] to Schimper’s genus
Anomozamites. Brongniart[1581] defined Pterophyllum fronds, e.g. P. Jaegeri
(fig. 610), as pinnate, bearing pinnules of almost equal breadth attached by
the whole width of the base and with a truncate apex; veins slender, equal,
simple and slightly arched. There has been considerable confusion and
laxity in regard to the application of the name Pterophyllum and in many
cases no clear distinction has been recognised between this genus and
Nilssonia. In Nilssonia the distinctive feature is the complete absence of
any rachis uncovered by the lamina on the upper face of well-preserved
specimens, while in Pterophyllum the continuity of the lamina is broken by
a greater or less breadth of rachis in the middle line of the frond; the lamina
does not cover the rachis but is attached laterally, or at least the two laminae
of the frond, whether entire or deeply dissected, do not meet in the middle
of the rachis. A specimen from the Cretaceous of Greenland described by
Heer as Pterophyllum concinnum[1582] and now in the Stockholm Museum is
Thomas and Bancroft.)
PTEROPHYLLUM. Brongniart.
The name Pterophyllum was first applied by Brongniart[1579] to some
fronds from the Lias of Höör, which he named P. majus and P. minus,
species subsequently removed by Nathorst[1580] to Schimper’s genus
Anomozamites. Brongniart[1581] defined Pterophyllum fronds, e.g. P. Jaegeri
(fig. 610), as pinnate, bearing pinnules of almost equal breadth attached by
the whole width of the base and with a truncate apex; veins slender, equal,
simple and slightly arched. There has been considerable confusion and
laxity in regard to the application of the name Pterophyllum and in many
cases no clear distinction has been recognised between this genus and
Nilssonia. In Nilssonia the distinctive feature is the complete absence of
any rachis uncovered by the lamina on the upper face of well-preserved
specimens, while in Pterophyllum the continuity of the lamina is broken by
a greater or less breadth of rachis in the middle line of the frond; the lamina
does not cover the rachis but is attached laterally, or at least the two laminae
of the frond, whether entire or deeply dissected, do not meet in the middle
of the rachis. A specimen from the Cretaceous of Greenland described by
Heer as Pterophyllum concinnum[1582] and now in the Stockholm Museum is
Page 596
probably a piece of a Nilssonia; the rachis is not exposed on the surface of
the frond. In Nilssonia the veins are with few exceptions simple; in
Pterophyllum they are often branched especially near their origin from the
rachis: in Nilssonia the segments are of unequal breadth; in Pterophyllum
they are usually equal. It has been the practice of several authors to follow
Schimper[1583] in the employment of the generic name Anomozamites for
fronds with a more or less entire or irregularly pinnatisect lamina which
bear a very close resemblance to Nilssonia except that a portion of the
rachis is exposed on the upper face. Potonié[1584] used Pterophyllum in a
wider sense including both fronds with equal pinnae and those of the
Anomozamites type: this more extended use of Pterophyllum is adopted by
Zeiller[1585] who prefers to retain Anomozamites only as a sub-genus. It is in
this sense that the following definition is framed.
Fig. 610. Pterophyllum Jaegeri. From the Keuper of Lunz; part of a
frond 23·5 cm. long and incomplete. (British Museum, V. 1044;
nat. size.)
Fronds pinnate; pinnae linear, attached by the whole base, which may be
enlarged; the apex is truncate, rounded, or occasionally pointed; the veins
are simple or dichotomously branched and parallel to the edge of the
lamina. In some fronds (sub-genus Anomozamites) the segments are
unequal (fig. 615), short, broad and truncate, and the lamina may be entire
or divided into a few very unequal segments. The surface of the rachis is
never completely covered by the lamina on the upper face of the frond and
is often characterised by transverse wrinklings, possibly due to the presence
of ramental scales.
Some interesting xerophilous features have recently been described by
Halle[1586] in the lamina of Pterophyllum (Anomozamites) marginatum, a
Rhaetic species figured by Schenk and Nathorst from Franconia and Scania.
The pinnae were thick and succulent. Stomata are confined to the lower
the frond. In Nilssonia the veins are with few exceptions simple; in
Pterophyllum they are often branched especially near their origin from the
rachis: in Nilssonia the segments are of unequal breadth; in Pterophyllum
they are usually equal. It has been the practice of several authors to follow
Schimper[1583] in the employment of the generic name Anomozamites for
fronds with a more or less entire or irregularly pinnatisect lamina which
bear a very close resemblance to Nilssonia except that a portion of the
rachis is exposed on the upper face. Potonié[1584] used Pterophyllum in a
wider sense including both fronds with equal pinnae and those of the
Anomozamites type: this more extended use of Pterophyllum is adopted by
Zeiller[1585] who prefers to retain Anomozamites only as a sub-genus. It is in
this sense that the following definition is framed.
Fig. 610. Pterophyllum Jaegeri. From the Keuper of Lunz; part of a
frond 23·5 cm. long and incomplete. (British Museum, V. 1044;
nat. size.)
Fronds pinnate; pinnae linear, attached by the whole base, which may be
enlarged; the apex is truncate, rounded, or occasionally pointed; the veins
are simple or dichotomously branched and parallel to the edge of the
lamina. In some fronds (sub-genus Anomozamites) the segments are
unequal (fig. 615), short, broad and truncate, and the lamina may be entire
or divided into a few very unequal segments. The surface of the rachis is
never completely covered by the lamina on the upper face of the frond and
is often characterised by transverse wrinklings, possibly due to the presence
of ramental scales.
Some interesting xerophilous features have recently been described by
Halle[1586] in the lamina of Pterophyllum (Anomozamites) marginatum, a
Rhaetic species figured by Schenk and Nathorst from Franconia and Scania.
The pinnae were thick and succulent. Stomata are confined to the lower
Page 597
surface and the edges of the upper face of the lamina form a rounded curve
causing the thick upper cuticle to abut on the thinner stomatiferous lower
cuticle, thus producing in impressions the appearance of thickened margins.
There is no satisfactory evidence as to the nature of the reproductive
organs or stems of the plants which bore fronds of the type represented by
P. Jaegeri (fig. 610) and other forms with equal segments. A stem referred
by Heer[1587] and by Leuthardt[1588] to Pterophyllum was not found in
connexion with leaves, and there is the same absence of any convincing
evidence in the case of the imperfect specimens from the Keuper of Basel
believed by Leuthardt to be male and female inflorescences. On the other
hand leaves of Anomozamites are known to have been borne on
comparatively slender stems with dichasial branching, and the reproductive
shoots are of the same general type as those known as Bennettites. This
discovery is due to Nathorst who founded the genus Wielandiella[1589] on
fertile stems with Anomozamites fronds. Mr Thomas[1590] has recently
obtained evidence from Yorkshire Jurassic material pointing to a similar
connexion between Anomozamites fronds and Wielandiella stems.
Pterophyllum is further distinguished from Nilssonia by the folded walls of
the epidermal cells and by the presence of two crescentic subsidiary cells
(fig. 611, A) instead of the ring of cells which surrounds the guard-cells in
Nilssonia (fig. 611, B). Schenk[1591] figured a few pieces of cuticle from
fronds referred to Pterophyllum in which the walls are more or less sinuous,
but the cells of Pterophyllum crassinerve Goepp.[1592] appear to have straight
walls: this species is, however, probably a Nilssonia. The stoma represented
in fig. 611, A, is from the lower epidermis of Pterophyllum (Anomozamites)
Nilssoni (Phill.)[1593].
Pterophyllum extends from Upper Carboniferous to Lower Cretaceous
strata and is especially characteristic of Keuper and Rhaetic floras. A
possible representative of the sub-genus Anomozamites is described by
Ettingshausen from Tertiary beds in New South Wales as Anomozamites
Muelleri[1594].
causing the thick upper cuticle to abut on the thinner stomatiferous lower
cuticle, thus producing in impressions the appearance of thickened margins.
There is no satisfactory evidence as to the nature of the reproductive
organs or stems of the plants which bore fronds of the type represented by
P. Jaegeri (fig. 610) and other forms with equal segments. A stem referred
by Heer[1587] and by Leuthardt[1588] to Pterophyllum was not found in
connexion with leaves, and there is the same absence of any convincing
evidence in the case of the imperfect specimens from the Keuper of Basel
believed by Leuthardt to be male and female inflorescences. On the other
hand leaves of Anomozamites are known to have been borne on
comparatively slender stems with dichasial branching, and the reproductive
shoots are of the same general type as those known as Bennettites. This
discovery is due to Nathorst who founded the genus Wielandiella[1589] on
fertile stems with Anomozamites fronds. Mr Thomas[1590] has recently
obtained evidence from Yorkshire Jurassic material pointing to a similar
connexion between Anomozamites fronds and Wielandiella stems.
Pterophyllum is further distinguished from Nilssonia by the folded walls of
the epidermal cells and by the presence of two crescentic subsidiary cells
(fig. 611, A) instead of the ring of cells which surrounds the guard-cells in
Nilssonia (fig. 611, B). Schenk[1591] figured a few pieces of cuticle from
fronds referred to Pterophyllum in which the walls are more or less sinuous,
but the cells of Pterophyllum crassinerve Goepp.[1592] appear to have straight
walls: this species is, however, probably a Nilssonia. The stoma represented
in fig. 611, A, is from the lower epidermis of Pterophyllum (Anomozamites)
Nilssoni (Phill.)[1593].
Pterophyllum extends from Upper Carboniferous to Lower Cretaceous
strata and is especially characteristic of Keuper and Rhaetic floras. A
possible representative of the sub-genus Anomozamites is described by
Ettingshausen from Tertiary beds in New South Wales as Anomozamites
Muelleri[1594].
Page 598
Fig. 611. A, Pterophyllum Nilssoni; B, Nilssonia mediana. (After Thomas
and Bancroft.)
Pterophyllum Fayoli Renault and Zeiller.
This species[1595] was founded on a large frond from the Commentry
coalfield with a stout rachis bearing linear pinnae, attached along a narrow
groove on its outer edge, reaching a length of 12 cm. and a breadth of 1
cm.; adjacent pinnae are united at the base. The apices are pointed and there
are 10–12 unbranched veins in the lamina. Fig. 612 shows a small piece of
the large specimen in the Natural History Museum, Paris.
Pterophyllum sp. Arber.
The only representative of a Carboniferous frond of Cycadean habit
discovered in Britain is that recorded by Arber[1596] from Westphalian strata
at a depth of 1834 ft at Barfreston in Kent. A fairly stout rachis bears
incomplete pinnae the longest of which is slightly more than 1 cm. in length
and 1–1·5 cm. broad; each segment, very slightly contracted at the base, has
3–4 occasionally forked veins. Arber compares the fragments with
Pterophyllum blechnoides Sand. from Germany[1597].
Pterophyllum Cambryi Renault.
This Permian species from Autun[1598] is similar to P. Fayoli, but differs in
the more slender rachis and in the finer venation of the linear, acute, pinnae.
The pinnae in Renault’s specimen reach a length of 4·8 cm. and are from
3·5–4 mm. broad; they are slightly confluent at the base and the veins
occasionally fork.
and Bancroft.)
Pterophyllum Fayoli Renault and Zeiller.
This species[1595] was founded on a large frond from the Commentry
coalfield with a stout rachis bearing linear pinnae, attached along a narrow
groove on its outer edge, reaching a length of 12 cm. and a breadth of 1
cm.; adjacent pinnae are united at the base. The apices are pointed and there
are 10–12 unbranched veins in the lamina. Fig. 612 shows a small piece of
the large specimen in the Natural History Museum, Paris.
Pterophyllum sp. Arber.
The only representative of a Carboniferous frond of Cycadean habit
discovered in Britain is that recorded by Arber[1596] from Westphalian strata
at a depth of 1834 ft at Barfreston in Kent. A fairly stout rachis bears
incomplete pinnae the longest of which is slightly more than 1 cm. in length
and 1–1·5 cm. broad; each segment, very slightly contracted at the base, has
3–4 occasionally forked veins. Arber compares the fragments with
Pterophyllum blechnoides Sand. from Germany[1597].
Pterophyllum Cambryi Renault.
This Permian species from Autun[1598] is similar to P. Fayoli, but differs in
the more slender rachis and in the finer venation of the linear, acute, pinnae.
The pinnae in Renault’s specimen reach a length of 4·8 cm. and are from
3·5–4 mm. broad; they are slightly confluent at the base and the veins
occasionally fork.
Page 599
Fig. 612. Pterophyllum Fayoli. (From the type-specimen, Paris; ⅓ nat.
size.)
Among other Palaeozoic species are Pterophyllum Grand’Euryanum Sap.
and Mar.[1599] discovered by Grand’Eury in the Coal Measures of France, P.
blechnoides Sand.[1600] from the Upper Coal Measures of Oppenau and
recorded by Geinitz[1601] from the Middle Permian of Germany, P.
Cottaeanum Gutb.[1602], a similar type, also from Permian rocks, but with
coarser venation. The specimens figured by Geinitz as P. blechnoides and P.
Cottaeanum are in the Dresden Museum: the former species is represented
by a good impression on shale which shows the generic characters very
clearly.
Pterophyllum Jaegeri Brongniart.
Brongniart[1603] founded this species (fig. 610) on material from the
Keuper of Stuttgart. The fronds are characterised by the relatively narrow
parallel-sided pinnae with rounded or truncate apices and little or no basal
contraction; the pinnae may be contiguous or separate. There are 14–16
veins in each pinna. Leuthardt[1604], who figures several examples of this
species from Keuper strata at Basel, speaks of the breadth-index of the
pinnae as 12, a term employed to denote the relation of the breadth to the
size.)
Among other Palaeozoic species are Pterophyllum Grand’Euryanum Sap.
and Mar.[1599] discovered by Grand’Eury in the Coal Measures of France, P.
blechnoides Sand.[1600] from the Upper Coal Measures of Oppenau and
recorded by Geinitz[1601] from the Middle Permian of Germany, P.
Cottaeanum Gutb.[1602], a similar type, also from Permian rocks, but with
coarser venation. The specimens figured by Geinitz as P. blechnoides and P.
Cottaeanum are in the Dresden Museum: the former species is represented
by a good impression on shale which shows the generic characters very
clearly.
Pterophyllum Jaegeri Brongniart.
Brongniart[1603] founded this species (fig. 610) on material from the
Keuper of Stuttgart. The fronds are characterised by the relatively narrow
parallel-sided pinnae with rounded or truncate apices and little or no basal
contraction; the pinnae may be contiguous or separate. There are 14–16
veins in each pinna. Leuthardt[1604], who figures several examples of this
species from Keuper strata at Basel, speaks of the breadth-index of the
pinnae as 12, a term employed to denote the relation of the breadth to the
Page 600
length of a segment. Pterophyllum longifolium[1605] is a very similar Keuper
type: in this species the pinnae are rather shorter and broader than in P.
Jaegeri and contracted at the base; the apex is truncate or obtuse. The
differences between these species is, however, very trifling. The imperfectly
preserved fossils figured by Leuthardt[1606] as the inflorescences of
Pterophyllum have not been found in connexion with fronds and their
nature is problematical. This and other species are recorded by Krasser[1607]
from the Lunz beds in Austria.
Pterophyllum Bronni Schenk.
A Keuper species[1608] from Raibl in Carinthia distinguished by its large
pinnae, 15 cm. or more in length and 0·5 cm. broad, and by their almost
digitate disposition on the rachis. The fronds appear to be relatively short:
the upper pinnae are highly inclined while the lower are given off at an
obtuse angle; they are obcuneate or more or less oblanceolate, with a
truncate asymmetrical apex and rounded angles; the base is slightly
contracted. Arber[1609] has figured some specimens from the Munich
Museum in one of which there are five spreading pinnae and a portion of
the rachis; one pinna is undoubtedly attached and the others, though
probably in place, are not in actual connexion with the axis. There is a close
resemblance between this species and Sphenozamites Rogersianus Font.
[1610]
: in the American type the fronds must have been 1 met. long; the
leaflets, 19 × 9 cm., are elliptical, broadest near the apex and attached by
the middle of the rounded base. Between the divergent and forked veins
there is a fine granulation probably due to the presence of papillae.
Pterophyllum Bronni and P. Rogersianum might be placed in Schimper’s
genus Macropterygium[1611], though another Raibl species, originally
described by Schenk as Pterophyllum giganteum[1612] and referred by
Schimper to Macropterygium, has much longer and relatively narrow
pinnae and agrees more closely with Pterophyllum as the genus is usually
defined. In order to emphasise the distinctive features of Pterophyllum
Bronni and Fontaine’s Virginian species they may conveniently be spoken
of as Pterophyllum (Macropterygium) Bronni and Pterophyllum
(Macropterygium) Rogersianum.
Pterophyllum Braunianum Goeppert.
type: in this species the pinnae are rather shorter and broader than in P.
Jaegeri and contracted at the base; the apex is truncate or obtuse. The
differences between these species is, however, very trifling. The imperfectly
preserved fossils figured by Leuthardt[1606] as the inflorescences of
Pterophyllum have not been found in connexion with fronds and their
nature is problematical. This and other species are recorded by Krasser[1607]
from the Lunz beds in Austria.
Pterophyllum Bronni Schenk.
A Keuper species[1608] from Raibl in Carinthia distinguished by its large
pinnae, 15 cm. or more in length and 0·5 cm. broad, and by their almost
digitate disposition on the rachis. The fronds appear to be relatively short:
the upper pinnae are highly inclined while the lower are given off at an
obtuse angle; they are obcuneate or more or less oblanceolate, with a
truncate asymmetrical apex and rounded angles; the base is slightly
contracted. Arber[1609] has figured some specimens from the Munich
Museum in one of which there are five spreading pinnae and a portion of
the rachis; one pinna is undoubtedly attached and the others, though
probably in place, are not in actual connexion with the axis. There is a close
resemblance between this species and Sphenozamites Rogersianus Font.
[1610]
: in the American type the fronds must have been 1 met. long; the
leaflets, 19 × 9 cm., are elliptical, broadest near the apex and attached by
the middle of the rounded base. Between the divergent and forked veins
there is a fine granulation probably due to the presence of papillae.
Pterophyllum Bronni and P. Rogersianum might be placed in Schimper’s
genus Macropterygium[1611], though another Raibl species, originally
described by Schenk as Pterophyllum giganteum[1612] and referred by
Schimper to Macropterygium, has much longer and relatively narrow
pinnae and agrees more closely with Pterophyllum as the genus is usually
defined. In order to emphasise the distinctive features of Pterophyllum
Bronni and Fontaine’s Virginian species they may conveniently be spoken
of as Pterophyllum (Macropterygium) Bronni and Pterophyllum
(Macropterygium) Rogersianum.
Pterophyllum Braunianum Goeppert.
Page 601
In this Rhaetic species[1613] (fig. 613) the
narrow linear pinnae, contiguous or more or less
distant, are 1–2 mm. broad and may exceed 5
cm. in length though they are usually shorter;
they are attached more or less at right-angles to
the sides of a transversely wrinkled rachis. The
base of the lamina is broadened and the veins
are parallel, simple or forked. The epidermal
cells have sinuous walls.
Pterophyllum Tietzei Schenk.
A Rhaetic species founded[1614] on specimens
from Persia and described also by Zeiller[1615]
from Tonkin represented by fronds 1 met. long
and at least 15 cm. broad. The segments, 3–7 Fig. 613. Pterophyllum
cm. long and 8–18 mm. broad, are often set at Braunianum. (A, nat.
right-angles to the rachis; the edges are parallel size; B, enlarged; after
but the lower edge bends upwards at the apex. Schenk.)
The veins are simple or forked and approximately 0·3 mm. apart.
Pterophyllum Bavieri Zeiller.
This Rhaetic species from Tonkin[1616] and Persia[1617] is interesting as
affording an example of a frond with exceptionally narrow and contiguous
pinnae. The frond is narrow and lanceolate, 15–20 cm. long with pinnae
normal to the rachis, ·5–1 mm. broad and 7–25 mm. long attached by the
whole base which is sometimes slightly enlarged. The veins are simple or
forked, ·15–·25 mm. apart: the apices of the segments are rounded or
truncate and the form of the whole is similar to that of Pterophyllum
aequale but narrower.
Pterophyllum (Anomozamites) inconstans Braun.
In habit this Rhaetic species[1618] resembles Nilssonia compta. The linear-
lanceolate fronds, as described by Zeiller[1619] in his Tonkin memoir, attain a
length of 20 cm. and a breadth of 4 cm. The rachis, characterised by
numerous transverse ridges, bears alternate or sub-opposite leaflets often at
right-angles; they are almost rectangular and hardly longer than broad,
narrow linear pinnae, contiguous or more or less
distant, are 1–2 mm. broad and may exceed 5
cm. in length though they are usually shorter;
they are attached more or less at right-angles to
the sides of a transversely wrinkled rachis. The
base of the lamina is broadened and the veins
are parallel, simple or forked. The epidermal
cells have sinuous walls.
Pterophyllum Tietzei Schenk.
A Rhaetic species founded[1614] on specimens
from Persia and described also by Zeiller[1615]
from Tonkin represented by fronds 1 met. long
and at least 15 cm. broad. The segments, 3–7 Fig. 613. Pterophyllum
cm. long and 8–18 mm. broad, are often set at Braunianum. (A, nat.
right-angles to the rachis; the edges are parallel size; B, enlarged; after
but the lower edge bends upwards at the apex. Schenk.)
The veins are simple or forked and approximately 0·3 mm. apart.
Pterophyllum Bavieri Zeiller.
This Rhaetic species from Tonkin[1616] and Persia[1617] is interesting as
affording an example of a frond with exceptionally narrow and contiguous
pinnae. The frond is narrow and lanceolate, 15–20 cm. long with pinnae
normal to the rachis, ·5–1 mm. broad and 7–25 mm. long attached by the
whole base which is sometimes slightly enlarged. The veins are simple or
forked, ·15–·25 mm. apart: the apices of the segments are rounded or
truncate and the form of the whole is similar to that of Pterophyllum
aequale but narrower.
Pterophyllum (Anomozamites) inconstans Braun.
In habit this Rhaetic species[1618] resembles Nilssonia compta. The linear-
lanceolate fronds, as described by Zeiller[1619] in his Tonkin memoir, attain a
length of 20 cm. and a breadth of 4 cm. The rachis, characterised by
numerous transverse ridges, bears alternate or sub-opposite leaflets often at
right-angles; they are almost rectangular and hardly longer than broad,
Page 602
attached by the whole of the base, which may be broadened, to the upper
face of the rachis, but the lamina does not cover the whole of the rachis as
in Nilssonia. The pinnae vary in breadth on the same frond and occasionally
the lamina is continuous as in some forms of Nilssonia. Schenk[1620] figures
examples from the Rhaetic of Franconia in which the lamina is very
irregularly dissected and may be entire for a considerable distance. The
epidermal cells have slightly sinuous walls. A similar type is represented by
Pterophyllum (Anomozamites) Schenki Zeill.[1621], but the segments are
contracted basally and become wider towards the apex where, as in P.
inconstans, the edges are parallel. Feistmantel’s species Platypterygium
Balli[1622], though superficially similar to Pterophyllum, appears to agree
more closely with Pseudoctenis.
Fig. 614. A, B, Pterophyllum Nathorsti; A from below; B from above. C,
Nilssonia tenuicaulis. (A, B, Gunn Collection, British Museum; C,
Arber Coll. Sedgwick Museum, 539; nat. size.)
Pterophyllum Nathorsti Seward.
This species, founded on a specimen in the Sedgwick Museum,
Cambridge, from the Middle Jurassic beds of Yorkshire, was formerly
referred to the genus Dioonites[1623], but since the Yorkshire specimens were
supplemented by material from Kimmeridge strata in Scotland[1624] affording
face of the rachis, but the lamina does not cover the whole of the rachis as
in Nilssonia. The pinnae vary in breadth on the same frond and occasionally
the lamina is continuous as in some forms of Nilssonia. Schenk[1620] figures
examples from the Rhaetic of Franconia in which the lamina is very
irregularly dissected and may be entire for a considerable distance. The
epidermal cells have slightly sinuous walls. A similar type is represented by
Pterophyllum (Anomozamites) Schenki Zeill.[1621], but the segments are
contracted basally and become wider towards the apex where, as in P.
inconstans, the edges are parallel. Feistmantel’s species Platypterygium
Balli[1622], though superficially similar to Pterophyllum, appears to agree
more closely with Pseudoctenis.
Fig. 614. A, B, Pterophyllum Nathorsti; A from below; B from above. C,
Nilssonia tenuicaulis. (A, B, Gunn Collection, British Museum; C,
Arber Coll. Sedgwick Museum, 539; nat. size.)
Pterophyllum Nathorsti Seward.
This species, founded on a specimen in the Sedgwick Museum,
Cambridge, from the Middle Jurassic beds of Yorkshire, was formerly
referred to the genus Dioonites[1623], but since the Yorkshire specimens were
supplemented by material from Kimmeridge strata in Scotland[1624] affording
Page 603
more definite information with regard to the attachment of the pinnae it has
been transferred to Pterophyllum. Pinnae laterally attached to the rachis
which in some specimens shows a transverse wrinkling, narrow, linear, 3–4
mm. wide and reaching a length of 9 cm. The base of the segments is
slightly expanded; the apex is acuminate or bluntly pointed: there are
approximately three veins in 1 mm. of lamina. This type (fig. 614, A, B) is
similar to Pterophyllum aequale Brongn. as figured by Zeiller[1625] from the
Rhaetic of Tonkin and agrees closely with some of the large Rhaetic
specimens referred by Schenk to P. Braunianum. The Jurassic fronds from
Oregon described by Fontaine[1626] as Ctenophyllum angustifolium are
similar forms and a specimen from the Wealden of Germany included by
Schenk in P. Dunkerianum[1627] should probably be included in this species.
Other closely allied forms are represented by P. distans Old. and Morr.[1628]
and P. Footeanum from India.
been transferred to Pterophyllum. Pinnae laterally attached to the rachis
which in some specimens shows a transverse wrinkling, narrow, linear, 3–4
mm. wide and reaching a length of 9 cm. The base of the segments is
slightly expanded; the apex is acuminate or bluntly pointed: there are
approximately three veins in 1 mm. of lamina. This type (fig. 614, A, B) is
similar to Pterophyllum aequale Brongn. as figured by Zeiller[1625] from the
Rhaetic of Tonkin and agrees closely with some of the large Rhaetic
specimens referred by Schenk to P. Braunianum. The Jurassic fronds from
Oregon described by Fontaine[1626] as Ctenophyllum angustifolium are
similar forms and a specimen from the Wealden of Germany included by
Schenk in P. Dunkerianum[1627] should probably be included in this species.
Other closely allied forms are represented by P. distans Old. and Morr.[1628]
and P. Footeanum from India.
Page 604
Fig. 616. Pterophyllum
(Anomozamites) Lyellianum.
(Geological Survey Museum,
6396; nat. size.)
Fig. 615. Pterophyllum
(Anomozamites) Nilssoni. (British
Museum, 39,306; nat. size.)
Pterophyllum (Anomozamites) Nilssoni (Phillips).
The type-specimen, from the Jurassic beds on the Yorkshire coast and
now in the York Museum, was described by Phillips[1629] as Aspleniopteris
(Anomozamites) Lyellianum.
(Geological Survey Museum,
6396; nat. size.)
Fig. 615. Pterophyllum
(Anomozamites) Nilssoni. (British
Museum, 39,306; nat. size.)
Pterophyllum (Anomozamites) Nilssoni (Phillips).
The type-specimen, from the Jurassic beds on the Yorkshire coast and
now in the York Museum, was described by Phillips[1629] as Aspleniopteris
Page 605
Nilssoni and placed in Pterophyllum by Lindley and Hutton and many other
authors[1630]. The fronds are linear; the lamina may be almost entire or
divided into unequal deep truncate segments; the veins are simple or
dichotomously branched (fig. 615). The leaves are very similar to those of
Nilssonia; they were probably borne on stems similar to those described by
Nathorst as Wielandiella. Reference is made to the structure of the
epidermal cells in the account of the genus.
Pterophyllum (Anomozamites) Lyellianum (Dunker).
This Wealden species, originally referred by Dunker[1631] to Pterophyllum,
was afterwards transferred to Anomozamites[1632]. The fronds, in habit
resembling the larger Rhaetic species P. Braunianum Goepp., are
characterised by the narrow linear pinnae of almost equal breadth attached
approximately at right angles; there is a narrow line of rachis separating the
two rows of segments (fig. 616).
{ CYCADITES. Sternberg.
PSEUDOCYCAS. Nathorst.
The generic name Cycadites was first used by Sternberg[1633] though it has
since been shown that the specimens for which he proposed it belong to
other genera. As employed by Brongniart[1634] and other authors Cycadites
stands for fossil fronds agreeing in habit with the pinnate leaves of recent
species of Cycas (fig. 387, A); the presence of a single median in the linear
pinnae is generally regarded as an essential feature. Cycadites may be
defined as follows: Fronds pinnate; pinnae alternate or opposite, linear
entire, with a midrib and no lateral veins, attached to the rachis by the entire
base, the lower margin of which may be slightly decurrent or narrowed near
the point of attachment. Epidermal cells with straight walls and stomata
agreeing in structure with those of the recent genus. As thus defined,
including the characters of the epidermal cells, the genus has no
representatives; but the generic name should also be applied, as Miss
Holden[1635] has recently suggested, to fronds of the Cycas form which
afford no information with regard to the structure of the epidermis. The
resemblance of Cycadites fronds to those of Cycas, coupled with the fact
that impressions superficially resembling megasporophylls of the recent
genus are recorded from Mesozoic strata, was considered sufficient
justification for the employment of a name implying close affinity to or
authors[1630]. The fronds are linear; the lamina may be almost entire or
divided into unequal deep truncate segments; the veins are simple or
dichotomously branched (fig. 615). The leaves are very similar to those of
Nilssonia; they were probably borne on stems similar to those described by
Nathorst as Wielandiella. Reference is made to the structure of the
epidermal cells in the account of the genus.
Pterophyllum (Anomozamites) Lyellianum (Dunker).
This Wealden species, originally referred by Dunker[1631] to Pterophyllum,
was afterwards transferred to Anomozamites[1632]. The fronds, in habit
resembling the larger Rhaetic species P. Braunianum Goepp., are
characterised by the narrow linear pinnae of almost equal breadth attached
approximately at right angles; there is a narrow line of rachis separating the
two rows of segments (fig. 616).
{ CYCADITES. Sternberg.
PSEUDOCYCAS. Nathorst.
The generic name Cycadites was first used by Sternberg[1633] though it has
since been shown that the specimens for which he proposed it belong to
other genera. As employed by Brongniart[1634] and other authors Cycadites
stands for fossil fronds agreeing in habit with the pinnate leaves of recent
species of Cycas (fig. 387, A); the presence of a single median in the linear
pinnae is generally regarded as an essential feature. Cycadites may be
defined as follows: Fronds pinnate; pinnae alternate or opposite, linear
entire, with a midrib and no lateral veins, attached to the rachis by the entire
base, the lower margin of which may be slightly decurrent or narrowed near
the point of attachment. Epidermal cells with straight walls and stomata
agreeing in structure with those of the recent genus. As thus defined,
including the characters of the epidermal cells, the genus has no
representatives; but the generic name should also be applied, as Miss
Holden[1635] has recently suggested, to fronds of the Cycas form which
afford no information with regard to the structure of the epidermis. The
resemblance of Cycadites fronds to those of Cycas, coupled with the fact
that impressions superficially resembling megasporophylls of the recent
genus are recorded from Mesozoic strata, was considered sufficient
justification for the employment of a name implying close affinity to or
Page 606
even generic identity with Cycas. A fuller knowledge of the epidermal
characters of some of the fronds hitherto included in Cycadites has
necessitated the substitution of a new genus for Cycadites. An examination
by Nathorst[1636] of Heer’s Lower Cretaceous Greenland species Cycadites
Steenstrupi and of other fronds showed that the epidermal cell-walls are
sinuous and the stomata arranged differently from those of Cycas. For these
and other reasons Nathorst proposed a new name Pseudocycas. He also
pointed out that the pinnae in the fossil fronds have as a rule a double
‘midrib.’ Nathorst’s discovery raised the question whether other fronds
described as Cycadites should be transferred to Pseudocycas. Miss
Holden’s investigation of other supposed Mesozoic representatives of
Cycas leads to the conclusion that ‘it is not impossible that all Mesozoic
specimens of Cycadites will turn out to be Pseudocycas.’ This observer
shows that Cycadites Saportae Sew. and C. Roemeri Schk. agree in the
sinuous walls of the epidermal cells with Pseudocycas; and so far no
species of Cycadites, in which it was possible to examine the cuticular
membrane, has been found that does not conform to Nathorst’s definition of
Pseudocycas at least as regards the structure of the epidermal cells.
Nathorst defined Pseudocycas in the following sense: Fronds similar to
those of Cycadites and Cycas but with pinnae characterised by a double
‘midrib,’ the stomata being confined or almost confined to the groove
between the two ‘midribs.’ Nathorst also notes that in Pseudocycas the
bases of the pinnae are not contracted as is often the case in Cycadites and
Cycas, but this is a feature of secondary importance. Miss Holden has,
however, expressed the opinion that the double ‘midrib’ is an untrustworthy
character and that the stomata are not always arranged as in the fronds
examined by Nathorst. Nathorst states that in Pseudocycas Steenstrupi and
P. insignis the midrib though usually double may be single: the same
variation occurs in P. Saportae. Miss Holden found that an impression made
from a pinna of Cycas siamensis showed a double line on the upper face
and a single rib on the lower; that is Pseudocycas and Cycas characters
occur on a single pinna. On drying, the ridge on the lower face of the
lamina collapses and a groove is formed bounded by two ridges.
In a recently published and interesting paper on ‘Some Xerophytic Leaf-
structures in Mesozoic Plants,’ Dr Halle[1637] makes some important
additions to our knowledge of Pseudocycas. He agrees with Miss Holden’s
views with regard to the use of the generic names Pseudocycas and
characters of some of the fronds hitherto included in Cycadites has
necessitated the substitution of a new genus for Cycadites. An examination
by Nathorst[1636] of Heer’s Lower Cretaceous Greenland species Cycadites
Steenstrupi and of other fronds showed that the epidermal cell-walls are
sinuous and the stomata arranged differently from those of Cycas. For these
and other reasons Nathorst proposed a new name Pseudocycas. He also
pointed out that the pinnae in the fossil fronds have as a rule a double
‘midrib.’ Nathorst’s discovery raised the question whether other fronds
described as Cycadites should be transferred to Pseudocycas. Miss
Holden’s investigation of other supposed Mesozoic representatives of
Cycas leads to the conclusion that ‘it is not impossible that all Mesozoic
specimens of Cycadites will turn out to be Pseudocycas.’ This observer
shows that Cycadites Saportae Sew. and C. Roemeri Schk. agree in the
sinuous walls of the epidermal cells with Pseudocycas; and so far no
species of Cycadites, in which it was possible to examine the cuticular
membrane, has been found that does not conform to Nathorst’s definition of
Pseudocycas at least as regards the structure of the epidermal cells.
Nathorst defined Pseudocycas in the following sense: Fronds similar to
those of Cycadites and Cycas but with pinnae characterised by a double
‘midrib,’ the stomata being confined or almost confined to the groove
between the two ‘midribs.’ Nathorst also notes that in Pseudocycas the
bases of the pinnae are not contracted as is often the case in Cycadites and
Cycas, but this is a feature of secondary importance. Miss Holden has,
however, expressed the opinion that the double ‘midrib’ is an untrustworthy
character and that the stomata are not always arranged as in the fronds
examined by Nathorst. Nathorst states that in Pseudocycas Steenstrupi and
P. insignis the midrib though usually double may be single: the same
variation occurs in P. Saportae. Miss Holden found that an impression made
from a pinna of Cycas siamensis showed a double line on the upper face
and a single rib on the lower; that is Pseudocycas and Cycas characters
occur on a single pinna. On drying, the ridge on the lower face of the
lamina collapses and a groove is formed bounded by two ridges.
In a recently published and interesting paper on ‘Some Xerophytic Leaf-
structures in Mesozoic Plants,’ Dr Halle[1637] makes some important
additions to our knowledge of Pseudocycas. He agrees with Miss Holden’s
views with regard to the use of the generic names Pseudocycas and
Page 607
Cycadites, but dissents from her interpretation of the median groove as the
result of shrinkage of a midrib. Part of the evidence presented by Halle is
based on the structure of the leaf-cuticle as shown in microtome
sections[1638]. He found that a distinct median groove is always present on
the pinnae of Pseudocycas insignis and other species. If the groove were
due to collapse of the tissue of a true median rib the presence of stomata—
which in P. insignis are confined to the middle line of the lamina—below
the vein would be an unusual feature. He found no indication of a median
vein or of any vascular tissue. All that is revealed by an examination of the
cuticle is that the lamina has a well-defined groove bounded by prominent
ridges, and in Pseudocycas Roemeri the groove is deeper and is formed by
the bending-back of the lamina. The stomata are practically confined to the
groove and in P. insignis and P. Steenstrupi an additional protection against
excessive transpiration was afforded by elongated papillae.
In the sinuous walls of the epidermal cells and in the structure of the
stomata Pseudocycas agrees with the Bennettitalean type as defined by
Thomas and Bancroft[1639]. The ‘midrib’ of the pinnae marks the position of
a pronounced groove and we have no information with regard to the
venation. As Halle says, protection against drought is afforded by ‘other
means than those usual among existing Cycads,’ which provide against
excessive transpiration by the sinking of the individual stomata below the
surface. The epidermal features of Pseudocycas afford a striking example of
the danger of basing conclusions on mere impressions and they further
emphasise the great difference between Mesozoic Cycadean fronds and
those of recent genera.
We have no knowledge of the nature of the reproductive organs of the
plants which bore Pseudocycas fronds, but the agreement of the stomata
and epidermal cells with those in some Bennettitalean types favours the
inclusion of the genus in that class. It has previously been pointed out that
the impression figured by Heer[1640] in close association with the Greenland
specimens of Pseudocycas Steenstrupi as a carpellary leaf of the Cycas type
is much too imperfect to be identified and has no claim, as an examination
of the actual specimen in the Copenhagen Museum convinced me, to be
compared with a megasporophyll of Cycas. This view is shared by
Nathorst.
result of shrinkage of a midrib. Part of the evidence presented by Halle is
based on the structure of the leaf-cuticle as shown in microtome
sections[1638]. He found that a distinct median groove is always present on
the pinnae of Pseudocycas insignis and other species. If the groove were
due to collapse of the tissue of a true median rib the presence of stomata—
which in P. insignis are confined to the middle line of the lamina—below
the vein would be an unusual feature. He found no indication of a median
vein or of any vascular tissue. All that is revealed by an examination of the
cuticle is that the lamina has a well-defined groove bounded by prominent
ridges, and in Pseudocycas Roemeri the groove is deeper and is formed by
the bending-back of the lamina. The stomata are practically confined to the
groove and in P. insignis and P. Steenstrupi an additional protection against
excessive transpiration was afforded by elongated papillae.
In the sinuous walls of the epidermal cells and in the structure of the
stomata Pseudocycas agrees with the Bennettitalean type as defined by
Thomas and Bancroft[1639]. The ‘midrib’ of the pinnae marks the position of
a pronounced groove and we have no information with regard to the
venation. As Halle says, protection against drought is afforded by ‘other
means than those usual among existing Cycads,’ which provide against
excessive transpiration by the sinking of the individual stomata below the
surface. The epidermal features of Pseudocycas afford a striking example of
the danger of basing conclusions on mere impressions and they further
emphasise the great difference between Mesozoic Cycadean fronds and
those of recent genera.
We have no knowledge of the nature of the reproductive organs of the
plants which bore Pseudocycas fronds, but the agreement of the stomata
and epidermal cells with those in some Bennettitalean types favours the
inclusion of the genus in that class. It has previously been pointed out that
the impression figured by Heer[1640] in close association with the Greenland
specimens of Pseudocycas Steenstrupi as a carpellary leaf of the Cycas type
is much too imperfect to be identified and has no claim, as an examination
of the actual specimen in the Copenhagen Museum convinced me, to be
compared with a megasporophyll of Cycas. This view is shared by
Nathorst.
Page 608
In some cases the name Cycadites has been applied to fragments that
might equally well belong to Conifers or other plants, and not infrequently a
careful examination of fossils referred to Cycadites shows that the pinnae
afford no evidence of a true midrib. Casts of revolute pinnae like those of
the recent species Encephalartos Ghellinckii (fig. 382) would present an
appearance closely resembling a strong midrib. Heer’s Siberian Jurassic
species Cycadites sibiricus[1641] is probably a piece of a Taeniopteris or
Nilssonia frond, and C. gramineus Heer[1642] should be referred to Taxites.
An examination of the Indian fronds described by Oldham and Morris and
Feistmantel as species of Cycadites leads me to discard all of them as
trustworthy records of the genus: in Cycadites confertus[1643] and C.
Blandfordianus[1644] there appear to be several veins in the pinnae and not a
single midrib. Cycadites constrictus[1645] is almost certainly a Conifer as
Nathorst has also suggested. No satisfactory example of Cycadites has been
described from Palaeozoic strata; Goeppert’s Cycadites gyrosus[1646] is
founded on material too imperfect to determine, and an examination of his
Culm species C. taxodinus in the Breslau Museum led me to refer it to a
Conifer. The specimens figured[1647] by Zeiller from Lower Gondwana rocks
in India as Cycadites? sp. are portions of linear leaves or leaflets 5 mm.
broad with a median rib but they can hardly be accepted as evidence of the
presence of a Cycadean plant.
might equally well belong to Conifers or other plants, and not infrequently a
careful examination of fossils referred to Cycadites shows that the pinnae
afford no evidence of a true midrib. Casts of revolute pinnae like those of
the recent species Encephalartos Ghellinckii (fig. 382) would present an
appearance closely resembling a strong midrib. Heer’s Siberian Jurassic
species Cycadites sibiricus[1641] is probably a piece of a Taeniopteris or
Nilssonia frond, and C. gramineus Heer[1642] should be referred to Taxites.
An examination of the Indian fronds described by Oldham and Morris and
Feistmantel as species of Cycadites leads me to discard all of them as
trustworthy records of the genus: in Cycadites confertus[1643] and C.
Blandfordianus[1644] there appear to be several veins in the pinnae and not a
single midrib. Cycadites constrictus[1645] is almost certainly a Conifer as
Nathorst has also suggested. No satisfactory example of Cycadites has been
described from Palaeozoic strata; Goeppert’s Cycadites gyrosus[1646] is
founded on material too imperfect to determine, and an examination of his
Culm species C. taxodinus in the Breslau Museum led me to refer it to a
Conifer. The specimens figured[1647] by Zeiller from Lower Gondwana rocks
in India as Cycadites? sp. are portions of linear leaves or leaflets 5 mm.
broad with a median rib but they can hardly be accepted as evidence of the
presence of a Cycadean plant.
Page 609
Fig. 617. Pseudocycas insignis. From the Lias of Höör. A, ⅚ nat. size; B,
ca. × 2. (After Nathorst.)
Pseudocycas insignis Nathorst.
The fronds of this Cenomanian species from the West of Greenland reach
a breadth of 16 cm.; the rachis, 1 cm. broad, has two parallel ridges on the
upper surface and to these are attached at a wide angle the broad bases of
narrow linear pinnae reaching a length of 9 cm. and a breadth of 2–3 mm.
(fig. 617). The pinnae are thick and separate and each has a double ‘midrib’
consisting of two parallel lines (fig. 617, B) which are occasionally replaced
by one. The so-called double ‘midrib’ represents the two prominent ridges
bordering the groove. The stomata, confined to the median groove, are
approximately circular and the short epidermal cells have sinuous walls[1648].
ca. × 2. (After Nathorst.)
Pseudocycas insignis Nathorst.
The fronds of this Cenomanian species from the West of Greenland reach
a breadth of 16 cm.; the rachis, 1 cm. broad, has two parallel ridges on the
upper surface and to these are attached at a wide angle the broad bases of
narrow linear pinnae reaching a length of 9 cm. and a breadth of 2–3 mm.
(fig. 617). The pinnae are thick and separate and each has a double ‘midrib’
consisting of two parallel lines (fig. 617, B) which are occasionally replaced
by one. The so-called double ‘midrib’ represents the two prominent ridges
bordering the groove. The stomata, confined to the median groove, are
approximately circular and the short epidermal cells have sinuous walls[1648].
Page 610
Pseudocycas Steenstrupi (Heer).
Nathorst refers this species, described by Heer as Cycadites, from the
Cenomanian of Greenland, to Pseudocycas on the ground that the epidermal
cells are like those of P. Steenstrupi and the stomata are confined to a
median groove. Heer figures an impression in close association with the
frond of this species which he identifies, without any adequate reason, as a
carpellary leaf like that of a Cycas.
Pseudocycas Saportae (Seward).
It has recently been shown by Miss Holden that this Wealden English
species[1649] has the epidermal characters of Pseudocycas. In external form it
agrees closely with Cycadites tenuisectus Sap.[1650] from Lower Cretaceous
rocks in Portugal, but nothing is known of the epidermal features of the
latter type. The rachis is broad and flattened and bears alternate or sub-
opposite pinnae of uniform breadth attached at right-angles or obliquely to
its upper surface (fig. 618). The pinnae are 6–7 cm. long and about 1 mm.
broad; their bases are slightly expanded and the apices sharply pointed.
Miss Holden[1651] finds that the median rib is sometimes double and that the
middle region of the lamina is covered with stomata; the epidermal cells
have sinuous walls and stomata occasionally occur on each side of the main
median stomatal area. Dr. Halle[1652] of Stockholm, who has examined
cuticular preparations made from English specimens, confirms Miss
Holden’s observations as regards the stomata, but he shows that there is no
evidence of the existence of a midrib in the strict sense, the appearance of a
single or double median vein being due to the presence of a dorsal
stomatiferous groove, the edges of which would produce an impression on
the matrix of a double vein or, if the groove became narrower, the
impression would suggest a single midrib.
Nathorst refers this species, described by Heer as Cycadites, from the
Cenomanian of Greenland, to Pseudocycas on the ground that the epidermal
cells are like those of P. Steenstrupi and the stomata are confined to a
median groove. Heer figures an impression in close association with the
frond of this species which he identifies, without any adequate reason, as a
carpellary leaf like that of a Cycas.
Pseudocycas Saportae (Seward).
It has recently been shown by Miss Holden that this Wealden English
species[1649] has the epidermal characters of Pseudocycas. In external form it
agrees closely with Cycadites tenuisectus Sap.[1650] from Lower Cretaceous
rocks in Portugal, but nothing is known of the epidermal features of the
latter type. The rachis is broad and flattened and bears alternate or sub-
opposite pinnae of uniform breadth attached at right-angles or obliquely to
its upper surface (fig. 618). The pinnae are 6–7 cm. long and about 1 mm.
broad; their bases are slightly expanded and the apices sharply pointed.
Miss Holden[1651] finds that the median rib is sometimes double and that the
middle region of the lamina is covered with stomata; the epidermal cells
have sinuous walls and stomata occasionally occur on each side of the main
median stomatal area. Dr. Halle[1652] of Stockholm, who has examined
cuticular preparations made from English specimens, confirms Miss
Holden’s observations as regards the stomata, but he shows that there is no
evidence of the existence of a midrib in the strict sense, the appearance of a
single or double median vein being due to the presence of a dorsal
stomatiferous groove, the edges of which would produce an impression on
the matrix of a double vein or, if the groove became narrower, the
impression would suggest a single midrib.
Page 611
Fig. 618. Pseudocycas Saportae. From the Wealden, near Hastings.
(British Museum, V. 2777; ⅕ nat. size.)
Pseudocycas Roemeri (Schenk).
This Wealden species recorded from North Germany[1653] and the Sussex
coast[1654] has broader pinnae laterally attached to the rachis. Miss Holden
describes the stomata as covering the whole lower surface of the pinnae
except over the midrib. This description must be revised in the light of
Halle’s results obtained from an examination of the cuticle of the type-
specimen of the species in the Berlin Museum. He finds that the edges of
(British Museum, V. 2777; ⅕ nat. size.)
Pseudocycas Roemeri (Schenk).
This Wealden species recorded from North Germany[1653] and the Sussex
coast[1654] has broader pinnae laterally attached to the rachis. Miss Holden
describes the stomata as covering the whole lower surface of the pinnae
except over the midrib. This description must be revised in the light of
Halle’s results obtained from an examination of the cuticle of the type-
specimen of the species in the Berlin Museum. He finds that the edges of
Page 612
the pinnae are strongly revolute and thus form a deep dorsal canal which is
almost closed[1655], a form of lamina, as seen in section, very similar to that
of an Empetrum leaf. The stomata are confined to the groove. It may be that
the specimen examined by Miss Holden is specifically distinct or, as Halle
also suggests, the cuticle obtained from the English fossil may not represent
the whole surface but only the walls of the canal with possibly a portion of
the cuticle of the outer dorsal surface. This type of leaf described by Halle
is similar to that of P. insignis with the xerophilous character intensified.
Cycadites Saladini Zeiller.
This species was founded by Zeiller[1656] on fronds from the Rhaetic of
Tonkin reaching a length of 40 cm. and 2–8·5 cm. broad with a rachis 3–4
mm. wide bearing contiguous linear pinnae 1·5–4·5 cm. long and 1·5–3
mm. broad with a more or less contracted base and a rounded or obtusely
pointed apex. The pinnae are attached almost at right-angles or at an angle
of 60°–80°. There is a clearly defined midrib.
It is not improbable that were the structure of the epidermal cells known
this species would be found to be another example of Pseudocycas.
Cycadites rectangularis Brauns.
This species[1657], first recorded from Rhaetic strata in Germany, differs in
the narrower and more acutely pointed pinnae from C. Saladini. Miss
Holden describes the midrib as double, but until specimens are found which
admit of an examination of the cuticles it is impossible to decide whether it
should be transferred to Pseudocycas. The species is widely distributed in
Rhaetic and Jurassic strata and specimens are recorded from the Lias of
Lyme Regis on the south coast of England.
Cycadites Renaulti Lignier.
This species, from the Middle Lias of Normandy[1658], is founded on
fronds 2·2–2·6 cm. broad with a rachis 3 mm. in breadth bearing laterally-
inserted pinnae almost at right-angles 11–12 mm. long and 1·25–1·50 mm.
broad; it is very similar to C. rectangularis which occurs in the same beds.
II. Nilssoniales.
almost closed[1655], a form of lamina, as seen in section, very similar to that
of an Empetrum leaf. The stomata are confined to the groove. It may be that
the specimen examined by Miss Holden is specifically distinct or, as Halle
also suggests, the cuticle obtained from the English fossil may not represent
the whole surface but only the walls of the canal with possibly a portion of
the cuticle of the outer dorsal surface. This type of leaf described by Halle
is similar to that of P. insignis with the xerophilous character intensified.
Cycadites Saladini Zeiller.
This species was founded by Zeiller[1656] on fronds from the Rhaetic of
Tonkin reaching a length of 40 cm. and 2–8·5 cm. broad with a rachis 3–4
mm. wide bearing contiguous linear pinnae 1·5–4·5 cm. long and 1·5–3
mm. broad with a more or less contracted base and a rounded or obtusely
pointed apex. The pinnae are attached almost at right-angles or at an angle
of 60°–80°. There is a clearly defined midrib.
It is not improbable that were the structure of the epidermal cells known
this species would be found to be another example of Pseudocycas.
Cycadites rectangularis Brauns.
This species[1657], first recorded from Rhaetic strata in Germany, differs in
the narrower and more acutely pointed pinnae from C. Saladini. Miss
Holden describes the midrib as double, but until specimens are found which
admit of an examination of the cuticles it is impossible to decide whether it
should be transferred to Pseudocycas. The species is widely distributed in
Rhaetic and Jurassic strata and specimens are recorded from the Lias of
Lyme Regis on the south coast of England.
Cycadites Renaulti Lignier.
This species, from the Middle Lias of Normandy[1658], is founded on
fronds 2·2–2·6 cm. broad with a rachis 3 mm. in breadth bearing laterally-
inserted pinnae almost at right-angles 11–12 mm. long and 1·25–1·50 mm.
broad; it is very similar to C. rectangularis which occurs in the same beds.
II. Nilssoniales.
Page 613
NILSSONIA. Brongniart.
This genus[1659] was named after the Swedish naturalist Nilsson who had
figured certain plants from the Lias of Höör referred by Fries to the Ferns:
these were named by Brongniart Nilssonia brevis and N. elongata and
classed with the Cycads. The type-specimens of the latter species are
regarded by Nathorst as a form of N. brevis. The history of the genus is
fully discussed in Nathorst’s able monograph[1660]. Nilssonia, founded on
fronds which with one exception are known only as casts or impressions,
may be thus defined: Fronds with circinate vernation, at least in the type-
species Nilssonia brevis (fig. 619, C, D), similar in shape to the leaves of
Scolopendrium vulgare and Polypodium irioides and to such unusual forms
of Cycas fronds as those reproduced in figs. 384, 387, I[1661], in which the
laminae of the pinnae are concrescent and form a continuous or deeply cut
lamina. They may reach a length of 60 cm. and a breadth of 10 cm. and
some specimens are known in which the leaf is less than 1 cm. in width.
The lamina is occasionally entire, but in the great majority of cases it is
more or less deeply cut into segments of unequal breadth varying
considerably in size and shape even in the same species, usually deep and
truncate and sometimes long and narrow (e.g. N. pterophylloides, fig. 619,
B). An important distinguishing feature is the attachment of the lamina to
the upper face of the rachis which it covers: the extension of the lamina
over the surface of the frond axis and the rare occurrence of branching of
the veins are characters in which Nilssonia differs from Taeniopteris. The
veins are given off at right-angles or obliquely from a very narrow groove
occupying the median line of the rachis; they are nearly always simple and
in some of the more fleshy leaves, e.g. N. brevis, they are seldom visible.
The surface of the lamina may be smooth or transversely corrugated. The
rachis forms a prominent rib on the under surface of the frond (fig. 620, A)
and may be continued beyond the lamina as a short petiole. Epidermal cells
polygonal or rectangular, with straight walls in contrast to the sinuous walls
of Taeniopteris; some of the cells bear strongly cuticularised papillae,
possibly the bases of hairs (compare the hairs on the fronds of Acrostichum
crinitum, a Fern with leaves similar in shape to some of the large entire
fronds of N. orientalis though relatively broader and with anastomosing
veins). Stomata usually confined to the lower epidermis and not very
numerous; guard-cells of rounded contour and without any special
thickening surrounded by 6–8 accessory cells with thickened walls (fig.
This genus[1659] was named after the Swedish naturalist Nilsson who had
figured certain plants from the Lias of Höör referred by Fries to the Ferns:
these were named by Brongniart Nilssonia brevis and N. elongata and
classed with the Cycads. The type-specimens of the latter species are
regarded by Nathorst as a form of N. brevis. The history of the genus is
fully discussed in Nathorst’s able monograph[1660]. Nilssonia, founded on
fronds which with one exception are known only as casts or impressions,
may be thus defined: Fronds with circinate vernation, at least in the type-
species Nilssonia brevis (fig. 619, C, D), similar in shape to the leaves of
Scolopendrium vulgare and Polypodium irioides and to such unusual forms
of Cycas fronds as those reproduced in figs. 384, 387, I[1661], in which the
laminae of the pinnae are concrescent and form a continuous or deeply cut
lamina. They may reach a length of 60 cm. and a breadth of 10 cm. and
some specimens are known in which the leaf is less than 1 cm. in width.
The lamina is occasionally entire, but in the great majority of cases it is
more or less deeply cut into segments of unequal breadth varying
considerably in size and shape even in the same species, usually deep and
truncate and sometimes long and narrow (e.g. N. pterophylloides, fig. 619,
B). An important distinguishing feature is the attachment of the lamina to
the upper face of the rachis which it covers: the extension of the lamina
over the surface of the frond axis and the rare occurrence of branching of
the veins are characters in which Nilssonia differs from Taeniopteris. The
veins are given off at right-angles or obliquely from a very narrow groove
occupying the median line of the rachis; they are nearly always simple and
in some of the more fleshy leaves, e.g. N. brevis, they are seldom visible.
The surface of the lamina may be smooth or transversely corrugated. The
rachis forms a prominent rib on the under surface of the frond (fig. 620, A)
and may be continued beyond the lamina as a short petiole. Epidermal cells
polygonal or rectangular, with straight walls in contrast to the sinuous walls
of Taeniopteris; some of the cells bear strongly cuticularised papillae,
possibly the bases of hairs (compare the hairs on the fronds of Acrostichum
crinitum, a Fern with leaves similar in shape to some of the large entire
fronds of N. orientalis though relatively broader and with anastomosing
veins). Stomata usually confined to the lower epidermis and not very
numerous; guard-cells of rounded contour and without any special
thickening surrounded by 6–8 accessory cells with thickened walls (fig.
Page 614
611, B) forming a chimney slightly raised over the stomatal pore[1662]. In
Nilssonia the guard-cells do not exhibit that regularity of orientation which
characterises the stomata of Ptilophyllum, Otozamites, and other
Bennettitalean fronds. Little is known of the anatomy of the leaves: in a
petrified leaf of N. orientalis[1663] from Upper Cretaceous rocks in Japan
there is no palisade-tissue and small groups of sclerenchyma occur above
and below the veins. The xylem appears to be centripetal, but the
preservation is far from satisfactory. A few secretory canals were found near
the edge of the leaf. We have no certain knowledge of the reproductive
organs. The small circular projections figured by Schenk[1664] on some
leaves of Nilssonia polymorpha as sporangia have no claim to be so
regarded. In the description of N. brevis reference is made to some seeds
discovered by Nathorst which may belong to that species. Nathorst suggests
the possibility that the Rhaetic fossil Stenorrachis scanicus Nath. may be
the seed-bearing shoot of a Nilssonia, either N. brevis or N. polymorpha,
and if this surmise is correct it almost necessarily involves the genus
Beania[1665] which has been tentatively referred to the Ginkgoales though
without any convincing evidence to support such connexion. Nothing is
known of the stems: the occasional occurrence of leaves converging
towards a common support points to a Cycadean habit. It is possible, as
Nathorst suggests, that the Rhaetic species Bucklandia Saportana[1666] may
be the stem of a Nilssonia.
Nilssonia the guard-cells do not exhibit that regularity of orientation which
characterises the stomata of Ptilophyllum, Otozamites, and other
Bennettitalean fronds. Little is known of the anatomy of the leaves: in a
petrified leaf of N. orientalis[1663] from Upper Cretaceous rocks in Japan
there is no palisade-tissue and small groups of sclerenchyma occur above
and below the veins. The xylem appears to be centripetal, but the
preservation is far from satisfactory. A few secretory canals were found near
the edge of the leaf. We have no certain knowledge of the reproductive
organs. The small circular projections figured by Schenk[1664] on some
leaves of Nilssonia polymorpha as sporangia have no claim to be so
regarded. In the description of N. brevis reference is made to some seeds
discovered by Nathorst which may belong to that species. Nathorst suggests
the possibility that the Rhaetic fossil Stenorrachis scanicus Nath. may be
the seed-bearing shoot of a Nilssonia, either N. brevis or N. polymorpha,
and if this surmise is correct it almost necessarily involves the genus
Beania[1665] which has been tentatively referred to the Ginkgoales though
without any convincing evidence to support such connexion. Nothing is
known of the stems: the occasional occurrence of leaves converging
towards a common support points to a Cycadean habit. It is possible, as
Nathorst suggests, that the Rhaetic species Bucklandia Saportana[1666] may
be the stem of a Nilssonia.
Page 615
Fig. 619. A, seed (Nilssonia?); B, Nilssonia pterophylloides; C, D,
Nilssonia brevis; E, N. polymorpha. (A–D ⅚ nat. size; E, slightly
enlarged; after Nathorst.)
Nilssonia is especially characteristic of Jurassic and Rhaetic floras; it
occurs also in Triassic beds and extends into Cretaceous floras.
Nathorst instituted the genus Nilssoniopteris[1667] for some specimens
from the Yorkshire coast which he believed to be examples of Nilssonia
tenuinervis on the ground that the veins are dichotomously branched and
Nilssonia brevis; E, N. polymorpha. (A–D ⅚ nat. size; E, slightly
enlarged; after Nathorst.)
Nilssonia is especially characteristic of Jurassic and Rhaetic floras; it
occurs also in Triassic beds and extends into Cretaceous floras.
Nathorst instituted the genus Nilssoniopteris[1667] for some specimens
from the Yorkshire coast which he believed to be examples of Nilssonia
tenuinervis on the ground that the veins are dichotomously branched and
Page 616
the epidermal cells have sinuous walls. Mr Hamshaw Thomas[1668] has,
however, shown by an examination of the specimens in the Stockholm
Museum that they belong to Taeniopteris vittata, and Prof. Nathorst agrees
with this conclusion. The name Nilssoniopteris must therefore be
abandoned. Miquel[1669] proposed the name Hisingera for some Nilssonia
fronds, but it has not been adopted.
Nilssonia polymorpha Schenk.
Linear fronds varying considerably in breadth and in the degree of
dissection of the lamina, which may be entire; the margin may show broad
and shallow crenulations or there may be a few narrow and deep sinuses
cutting the otherwise entire lamina into long and narrow segments. More
usually the lamina is divided to the rachis into numerous truncate segments
traversed by parallel, simple, veins extending from a narrow groove in the
middle of the rachis on the upper surface of the frond (fig. 619, E). The
veins run in very narrow grooves in the generally flat but occasionally
corrugated lamina[1670].
This species agrees very closely in habit with N. compta and N. brevis
and, as Nathorst points out, it is in some cases almost impossible to
distinguish Nilssonia polymorpha from N. brevis. Some of the fronds from
the Rhaetic of Franconia described by Schenk as N. polymorpha are
examples of N. brevis. In N. polymorpha the distal ends of the segments are
blunter, the lamina is much less folded and when folds or corrugations
occur they are less regular than in N. brevis. The epidermal cells are
polygonal and have thick, straight, walls: oval or circular papillae occur
both on the lamina and rachis. The stomata, confined to the lower surface,
are between the veins and each is accompanied by a ring of subsidiary cells
(cf. fig. 611, B). N. polymorpha is a member of Rhaetic floras and is
recorded also from Liassic rocks at Höör[1671].
however, shown by an examination of the specimens in the Stockholm
Museum that they belong to Taeniopteris vittata, and Prof. Nathorst agrees
with this conclusion. The name Nilssoniopteris must therefore be
abandoned. Miquel[1669] proposed the name Hisingera for some Nilssonia
fronds, but it has not been adopted.
Nilssonia polymorpha Schenk.
Linear fronds varying considerably in breadth and in the degree of
dissection of the lamina, which may be entire; the margin may show broad
and shallow crenulations or there may be a few narrow and deep sinuses
cutting the otherwise entire lamina into long and narrow segments. More
usually the lamina is divided to the rachis into numerous truncate segments
traversed by parallel, simple, veins extending from a narrow groove in the
middle of the rachis on the upper surface of the frond (fig. 619, E). The
veins run in very narrow grooves in the generally flat but occasionally
corrugated lamina[1670].
This species agrees very closely in habit with N. compta and N. brevis
and, as Nathorst points out, it is in some cases almost impossible to
distinguish Nilssonia polymorpha from N. brevis. Some of the fronds from
the Rhaetic of Franconia described by Schenk as N. polymorpha are
examples of N. brevis. In N. polymorpha the distal ends of the segments are
blunter, the lamina is much less folded and when folds or corrugations
occur they are less regular than in N. brevis. The epidermal cells are
polygonal and have thick, straight, walls: oval or circular papillae occur
both on the lamina and rachis. The stomata, confined to the lower surface,
are between the veins and each is accompanied by a ring of subsidiary cells
(cf. fig. 611, B). N. polymorpha is a member of Rhaetic floras and is
recorded also from Liassic rocks at Höör[1671].
Page 617
Fig. 620. A, B, Nilssonia brevis; A, section of the frond; B, section of the
lamina parallel to the rachis. C, N. saighensis. (A, B, after Nathorst.)
Nilssonia brevis Brongniart.
This species[1672] (fig. 619, C, D), one of those from Höör on which the
genus was founded, has been very fully investigated by Nathorst[1673] whose
researches have cleared up many obscure features. The young fronds are
circinate like those of Ferns and Cycas. The linear fronds agree generally in
habit with those of N. polymorpha and N. compta, but the lamina is thicker
and is characterised by regular transverse corrugations; the veins are very
rarely visible except in young leaves which have not reached their full
thickness. The fronds may be 50 cm. long and vary in breadth from 1·5 to
12 cm.; the petiole is very short or the frond may be sessile. Between the
regular grooves on the upper surface the lamina is more or less convex;
seen from below the grooves are represented by ridges and between each
pair of ridges there are parallel folds, sometimes three (fig. 620, B) or as
many as six; and where the segments are narrow, that is the strips of lamina
between two grooves (or ridges), there may be only a single fold which
gives the appearance of linear segments with a single midrib as in
Cycadites, a misleading resemblance of special interest in reference to the
Nilssonia fronds described by Oldham and Morris[1674] and by
Feistmantel[1675] as Cycadites rajmahalensis. Owing to the fleshy nature of
the leaf the difference between the upper and lower side is particularly well
marked in this species. The lamina may be more or less entire, but is usually
divided by deep sinuses extending to the rachis into truncate or distally
tapered segments varying in breadth (fig. 619, C, D), the narrow segments
being characterised by a more pointed apex than in N. polymorpha. The
lamina parallel to the rachis. C, N. saighensis. (A, B, after Nathorst.)
Nilssonia brevis Brongniart.
This species[1672] (fig. 619, C, D), one of those from Höör on which the
genus was founded, has been very fully investigated by Nathorst[1673] whose
researches have cleared up many obscure features. The young fronds are
circinate like those of Ferns and Cycas. The linear fronds agree generally in
habit with those of N. polymorpha and N. compta, but the lamina is thicker
and is characterised by regular transverse corrugations; the veins are very
rarely visible except in young leaves which have not reached their full
thickness. The fronds may be 50 cm. long and vary in breadth from 1·5 to
12 cm.; the petiole is very short or the frond may be sessile. Between the
regular grooves on the upper surface the lamina is more or less convex;
seen from below the grooves are represented by ridges and between each
pair of ridges there are parallel folds, sometimes three (fig. 620, B) or as
many as six; and where the segments are narrow, that is the strips of lamina
between two grooves (or ridges), there may be only a single fold which
gives the appearance of linear segments with a single midrib as in
Cycadites, a misleading resemblance of special interest in reference to the
Nilssonia fronds described by Oldham and Morris[1674] and by
Feistmantel[1675] as Cycadites rajmahalensis. Owing to the fleshy nature of
the leaf the difference between the upper and lower side is particularly well
marked in this species. The lamina may be more or less entire, but is usually
divided by deep sinuses extending to the rachis into truncate or distally
tapered segments varying in breadth (fig. 619, C, D), the narrow segments
being characterised by a more pointed apex than in N. polymorpha. The
Page 618
structure of the stomata and epidermal cells is of the type described in the
definition of the genus. Strongly cuticularised papillae, incorrectly
described by Schenk[1676] in N. polymorpha as stomata, occur on some of the
epidermal cells: these may be the bases of hairs. In some preparations
Nathorst found patches of a resinous substance, an interesting discovery in
view of the occurrence of secretory canals in the petrified leaf of Nilssonia
orientalis described by Dr Stopes[1677].
Fig. 621. Nilssonia rajmahalensis (= Cycadites rajmahalensis). (Indian
Geological Survey, Calcutta; nat. size.)
definition of the genus. Strongly cuticularised papillae, incorrectly
described by Schenk[1676] in N. polymorpha as stomata, occur on some of the
epidermal cells: these may be the bases of hairs. In some preparations
Nathorst found patches of a resinous substance, an interesting discovery in
view of the occurrence of secretory canals in the petrified leaf of Nilssonia
orientalis described by Dr Stopes[1677].
Fig. 621. Nilssonia rajmahalensis (= Cycadites rajmahalensis). (Indian
Geological Survey, Calcutta; nat. size.)
Page 619
Nilssonia brevis occurs in Upper Rhaetic and Lower Liassic strata.
Nilssonia pterophylloides Nathorst.
A Rhaetic Scanian species originally referred by Nathorst[1678] to
Nilssonia but later removed by him to Dioonites[1679] and in 1909 reinstated
in Nilssonia[1680] on the ground that the lamina covers the upper face of the
rachis. The segments are fairly uniform in breadth and linear; they reach 10
cm. in length and are usually 5–7 mm. broad; the lamina is slightly tapered
towards the apex (fig. 619, B). There are 3–10 parallel grooves on the upper
face of the segments and between each pair is a single unbranched vein. In
close association with portions of three fronds of this species Nathorst
found several oval bodies, 1 cm. × 7 mm., which he at first regarded as
‘antherangia’ comparable with the sporocarps of the Hydropterideae, but an
examination of the carbonised tissue demonstrated that the small rounded
bodies contained in each of the ‘antherangia,’ originally believed to be
pollen-sacs, are grains of resin internal to a cuticle of thick-walled cells and
probably formed by secretory sacs in a fleshy tissue. Internal to the resin-
bodies is a second cuticle which may be the remains of a nucellus, the outer
cuticle and the resin belonging to the sarcotesta. Nathorst’s careful
examination of these fossils shows that they are seeds (fig. 619, A) and
were probably borne on plants of N. pterophylloides, though an accidental
association is not improbable.
Nilssonia compta (Phillips).
Broadly linear fronds varying considerably in size and in the breadth and
number of the truncate segments. In some cases the fronds exceeded 40 cm.
in length and had a breadth of 9 cm. (fig. 622). The veins are simple,
parallel, and fairly prominent and the lamina shows clearly the attachment
to the upper surface of the rachis which is covered by it as in all species of
the genus[1681]. The structure of the epidermis and stomata has recently been
described by Thomas[1682]. Brongniart mentioned in the Prodrome a species
from the Lower Oolite of Yorkshire under the name Pterophyllum
Williamsonis[1683], but in a later work this is given as a synonym of N.
compta. Nilssonia compta bears a close resemblance in habit to N.
polymorpha; it agrees also with the large fronds described from the Upper
Gondwana of India as Pterophyllum princeps[1684]. Since attention was first
Nilssonia pterophylloides Nathorst.
A Rhaetic Scanian species originally referred by Nathorst[1678] to
Nilssonia but later removed by him to Dioonites[1679] and in 1909 reinstated
in Nilssonia[1680] on the ground that the lamina covers the upper face of the
rachis. The segments are fairly uniform in breadth and linear; they reach 10
cm. in length and are usually 5–7 mm. broad; the lamina is slightly tapered
towards the apex (fig. 619, B). There are 3–10 parallel grooves on the upper
face of the segments and between each pair is a single unbranched vein. In
close association with portions of three fronds of this species Nathorst
found several oval bodies, 1 cm. × 7 mm., which he at first regarded as
‘antherangia’ comparable with the sporocarps of the Hydropterideae, but an
examination of the carbonised tissue demonstrated that the small rounded
bodies contained in each of the ‘antherangia,’ originally believed to be
pollen-sacs, are grains of resin internal to a cuticle of thick-walled cells and
probably formed by secretory sacs in a fleshy tissue. Internal to the resin-
bodies is a second cuticle which may be the remains of a nucellus, the outer
cuticle and the resin belonging to the sarcotesta. Nathorst’s careful
examination of these fossils shows that they are seeds (fig. 619, A) and
were probably borne on plants of N. pterophylloides, though an accidental
association is not improbable.
Nilssonia compta (Phillips).
Broadly linear fronds varying considerably in size and in the breadth and
number of the truncate segments. In some cases the fronds exceeded 40 cm.
in length and had a breadth of 9 cm. (fig. 622). The veins are simple,
parallel, and fairly prominent and the lamina shows clearly the attachment
to the upper surface of the rachis which is covered by it as in all species of
the genus[1681]. The structure of the epidermis and stomata has recently been
described by Thomas[1682]. Brongniart mentioned in the Prodrome a species
from the Lower Oolite of Yorkshire under the name Pterophyllum
Williamsonis[1683], but in a later work this is given as a synonym of N.
compta. Nilssonia compta bears a close resemblance in habit to N.
polymorpha; it agrees also with the large fronds described from the Upper
Gondwana of India as Pterophyllum princeps[1684]. Since attention was first
Page 620
called to this similarity an examination of several of the figured specimens
has convinced me that the Indian fronds are either identical with or at least
closely allied to the European leaves. The apparent lateral attachment of the
lamina in the drawings published by Oldham and Morris and Feistmantel is
due to imperfect preservation; the lamina ends in two raised ridges, and the
discovery of a specimen in which the lamina completely covers the rachis
confirmed the impression made by the other specimens. The Amurland
Jurassic species Nilssonia Schmidtii[1685] Heer though probably not identical
with N. compta is a very similar type; it was originally described by Heer as
Anomozamites Schmidtii and transferred by Nathorst[1686] to Nilssonia: the
veins are occasionally forked near the rachis and are rather farther apart (·5
mm.) than in N. compta and the segments are broader and deeper than in the
English species. Nilssonia nipponensis Yok.[1687] a Jurassic species recorded
from Japan and North America is another similar type.
Fig. 622. Nilssonia compta. (Whitby Museum; nat. size.)
has convinced me that the Indian fronds are either identical with or at least
closely allied to the European leaves. The apparent lateral attachment of the
lamina in the drawings published by Oldham and Morris and Feistmantel is
due to imperfect preservation; the lamina ends in two raised ridges, and the
discovery of a specimen in which the lamina completely covers the rachis
confirmed the impression made by the other specimens. The Amurland
Jurassic species Nilssonia Schmidtii[1685] Heer though probably not identical
with N. compta is a very similar type; it was originally described by Heer as
Anomozamites Schmidtii and transferred by Nathorst[1686] to Nilssonia: the
veins are occasionally forked near the rachis and are rather farther apart (·5
mm.) than in N. compta and the segments are broader and deeper than in the
English species. Nilssonia nipponensis Yok.[1687] a Jurassic species recorded
from Japan and North America is another similar type.
Fig. 622. Nilssonia compta. (Whitby Museum; nat. size.)
Page 621
Nilssonia orientalis Heer.
In this Jurassic and Lower Cretaceous species, founded on material from
Jurassic rocks in Siberia[1688], the lamina is generally entire. The fronds
exhibit a wide range in size and shape; they may have the form of very
narrow linear leaves barely 1 cm. across or may reach a breadth of nearly
10 cm. The leaves from Middle Jurassic British strata named by Nathorst N.
tenuinervis[1689] are probably identical with Heer’s type, and N.
Johnstrupi[1690] Heer from the Lower Cretaceous of Greenland may also be
referred to N. orientalis.
The veins are at right-angles or oblique to the rachis and are very
numerous, three or more in a breadth of 1 mm.[1691] A species recently
described by Halle[1692] from Graham Land as N. taeniopteroides agrees
closely in habit with N. orientalis: in the southern form the frond may have
a length of 40–50 cm. and a breadth of 3 cm. The entire lamina of N.
taeniopteroides tapers gradually towards the base and is more rapidly
narrowed in the distal region; the petiole is at least 6–7 cm. long: the simple
or branched veins, 15–20 in 1 cm., are given off from the axis at a wide
angle. The more crowded veins in N. orientalis constitute one of the few
features in which it differs from Halle’s species, but the fact that the degree
of closeness of the veins is inconstant within the same species renders this
distinction of doubtful value. Halle compares his species also with N.
densinervis (Font.) originally described as Platypterigium densinerve from
the Potomac beds[1693] and afterwards transferred by Berry[1694] to Nilssonia
and considered by him to be identical with Fontaine’s Platypterigium
Rogersianum. An examination of some of Fontaine’s specimens in the
Washington Museum led me to refer the fronds to Nilssonia[1695].
It is impossible to speak with confidence as to the absolute specific
identity of N. orientalis Heer, N. Johnstrupi Heer, N. taeniopteroides Halle,
and some similar forms; but it is clear that the linear fronds of this type
characterised by an entire or occasionally pinnatisect lamina were widely
distributed in Jurassic and Lower Cretaceous strata and persisted to the
Upper Cretaceous series in Japan. This form of frond is recorded from
England, Scotland, North America, Greenland, Spitzbergen[1696], Siberia,
Russia, Afghanistan[1697], Japan[1698], Graham Land, and elsewhere.
In this Jurassic and Lower Cretaceous species, founded on material from
Jurassic rocks in Siberia[1688], the lamina is generally entire. The fronds
exhibit a wide range in size and shape; they may have the form of very
narrow linear leaves barely 1 cm. across or may reach a breadth of nearly
10 cm. The leaves from Middle Jurassic British strata named by Nathorst N.
tenuinervis[1689] are probably identical with Heer’s type, and N.
Johnstrupi[1690] Heer from the Lower Cretaceous of Greenland may also be
referred to N. orientalis.
The veins are at right-angles or oblique to the rachis and are very
numerous, three or more in a breadth of 1 mm.[1691] A species recently
described by Halle[1692] from Graham Land as N. taeniopteroides agrees
closely in habit with N. orientalis: in the southern form the frond may have
a length of 40–50 cm. and a breadth of 3 cm. The entire lamina of N.
taeniopteroides tapers gradually towards the base and is more rapidly
narrowed in the distal region; the petiole is at least 6–7 cm. long: the simple
or branched veins, 15–20 in 1 cm., are given off from the axis at a wide
angle. The more crowded veins in N. orientalis constitute one of the few
features in which it differs from Halle’s species, but the fact that the degree
of closeness of the veins is inconstant within the same species renders this
distinction of doubtful value. Halle compares his species also with N.
densinervis (Font.) originally described as Platypterigium densinerve from
the Potomac beds[1693] and afterwards transferred by Berry[1694] to Nilssonia
and considered by him to be identical with Fontaine’s Platypterigium
Rogersianum. An examination of some of Fontaine’s specimens in the
Washington Museum led me to refer the fronds to Nilssonia[1695].
It is impossible to speak with confidence as to the absolute specific
identity of N. orientalis Heer, N. Johnstrupi Heer, N. taeniopteroides Halle,
and some similar forms; but it is clear that the linear fronds of this type
characterised by an entire or occasionally pinnatisect lamina were widely
distributed in Jurassic and Lower Cretaceous strata and persisted to the
Upper Cretaceous series in Japan. This form of frond is recorded from
England, Scotland, North America, Greenland, Spitzbergen[1696], Siberia,
Russia, Afghanistan[1697], Japan[1698], Graham Land, and elsewhere.
Page 622
Reference has already been made to a petrified specimen of N. orientalis
described by Dr Stopes from Japan[1699].
Specimens described by Salfeld[1700] from the Corallian of Germany as
Taeniopteris sp. may be N. orientalis; Bartholin’s N. polymorpha from
Bornholm, Velenovský’s Lower Cretaceous N. bohemica and Yokoyama’s
N. ozvana from Japan are other examples of fronds which may be identical
with N. orientalis[1701].
Nilssonia tenuicaulis (Phillips).
This Jurassic species, while agreeing generally in habit with N. compta,
is characterised by the narrow and numerous linear segments with a more
acuminate apex. The fronds reached a length of more than 20 cm.[1702]
Leckenby’s name Pterophyllum medianum[1703] was given to a specimen
from the Yorkshire coast and now in the Sedgwick Museum, Cambridge,
which, with Pterophyllum angustifolium, is clearly identical with Cycadites
tenuicaulis Phillips. The specific name mediana frequently used[1704] for this
type should be given up in favour of the older term tenuicaulis. A species of
similar habit is described but not figured by Krasser[1705] as N. Sturii from
the Lunz beds. N. tenuicaulis is fairly common in the Middle Jurassic beds
near Scarborough and is recorded from the Kimmeridgian of Scotland
under the name N. mediana (fig. 614, C)[1706].
Nilssonia princeps (Oldham and Morris).
Oldham and Morris speak of Pterophyllum princeps[1707] as one of the
commonest plants in the Rajmahal beds in India. The fronds are
characterised by their large size and by the very broad oblong and distally
truncate pinnae with parallel and occasionally branched veins. In the
specimens figured by Oldham and Morris and Feistmantel the pinnae are
cut off at their bases (fig. 623), which form ridges parallel to the rachis: this
feature is not clearly shown in the published drawings. By breaking some
pieces of rock from a slab containing figured specimens other pieces were
found in which the laminae of the bases of segments meet in the middle of
the upper face of the rachis. The pinnae vary in breadth from 1 cm. to 3·5
cm. and reach a length of 8 cm.; the distal end is truncate, the lower edge
being strongly curved: the segments are slightly broadened at the base. The
veins are prominent and parallel, from 0·5 to 0·8 mm. apart. The Rajmahal
described by Dr Stopes from Japan[1699].
Specimens described by Salfeld[1700] from the Corallian of Germany as
Taeniopteris sp. may be N. orientalis; Bartholin’s N. polymorpha from
Bornholm, Velenovský’s Lower Cretaceous N. bohemica and Yokoyama’s
N. ozvana from Japan are other examples of fronds which may be identical
with N. orientalis[1701].
Nilssonia tenuicaulis (Phillips).
This Jurassic species, while agreeing generally in habit with N. compta,
is characterised by the narrow and numerous linear segments with a more
acuminate apex. The fronds reached a length of more than 20 cm.[1702]
Leckenby’s name Pterophyllum medianum[1703] was given to a specimen
from the Yorkshire coast and now in the Sedgwick Museum, Cambridge,
which, with Pterophyllum angustifolium, is clearly identical with Cycadites
tenuicaulis Phillips. The specific name mediana frequently used[1704] for this
type should be given up in favour of the older term tenuicaulis. A species of
similar habit is described but not figured by Krasser[1705] as N. Sturii from
the Lunz beds. N. tenuicaulis is fairly common in the Middle Jurassic beds
near Scarborough and is recorded from the Kimmeridgian of Scotland
under the name N. mediana (fig. 614, C)[1706].
Nilssonia princeps (Oldham and Morris).
Oldham and Morris speak of Pterophyllum princeps[1707] as one of the
commonest plants in the Rajmahal beds in India. The fronds are
characterised by their large size and by the very broad oblong and distally
truncate pinnae with parallel and occasionally branched veins. In the
specimens figured by Oldham and Morris and Feistmantel the pinnae are
cut off at their bases (fig. 623), which form ridges parallel to the rachis: this
feature is not clearly shown in the published drawings. By breaking some
pieces of rock from a slab containing figured specimens other pieces were
found in which the laminae of the bases of segments meet in the middle of
the upper face of the rachis. The pinnae vary in breadth from 1 cm. to 3·5
cm. and reach a length of 8 cm.; the distal end is truncate, the lower edge
being strongly curved: the segments are slightly broadened at the base. The
veins are prominent and parallel, from 0·5 to 0·8 mm. apart. The Rajmahal
Page 623
fronds described as Pterophyllum Morrisianum[1708] appear to be
indistinguishable from this species.
Fig. 623. Nilssonia princeps. (Slightly reduced; Indian Geological
Survey, Calcutta.)
Nilssonia Schaumburgensis (Dunker).
This species, first described as Pterophyllum Schaumburgense[1709] from
the Wealden of Germany, affords a good illustration of a small type of frond
closely resembling the much larger species N. compta. Examples from
English Wealden rocks seldom exceed 1 cm. in breadth and are often much
narrower; the linear lamina is almost entire or divided into short and broad
truncate segments of unequal breadth: the veins are parallel and simple. For
figures of this species, recorded from different European localities and from
Japan, reference should be made to the accounts by Schenk[1710], Nathorst,
Yokoyama, Yabe, and Fontaine.
indistinguishable from this species.
Fig. 623. Nilssonia princeps. (Slightly reduced; Indian Geological
Survey, Calcutta.)
Nilssonia Schaumburgensis (Dunker).
This species, first described as Pterophyllum Schaumburgense[1709] from
the Wealden of Germany, affords a good illustration of a small type of frond
closely resembling the much larger species N. compta. Examples from
English Wealden rocks seldom exceed 1 cm. in breadth and are often much
narrower; the linear lamina is almost entire or divided into short and broad
truncate segments of unequal breadth: the veins are parallel and simple. For
figures of this species, recorded from different European localities and from
Japan, reference should be made to the accounts by Schenk[1710], Nathorst,
Yokoyama, Yabe, and Fontaine.
Page 624
CTENIS. Lindley and Hutton.
The genus Ctenis[1711] was founded on a piece of pinnate frond from the
Middle Jurassic rocks of the Yorkshire coast previously figured by Phillips
as Cycadites sulcicaulis. Lindley and Hutton regarded the plant as probably
Cycadean and proposed to apply the name Ctenis to all leaves having the
general characters of Cycadeae, but with ‘the veins connected by forks or
transverse bars.’ While many authors have accepted Ctenis as a Cycadean
genus, by others[1712] it has been placed among the Ferns, on the ground that
some small circular elevations on the lamina of the segments of certain
species are believed to be sori or sporangia. Since Ettingshausen[1713] and
Schenk[1714] first noticed this feature Raciborski[1715] has figured several
examples from Poland and Staub[1716] records similar circular bodies on a
Liassic Hungarian species. In no single instance have sporangia been found.
Nathorst[1717] proposed the designation Anthrophyopsis (because of the
resemblance of the lamina in form and venation to the leaves of the Fern
Anthrophyum) for some Rhaetic specimens from Scania, but as they were
subsequently found to be segments of a pinnate frond he adopted the name
Ctenis. An example in the Manchester Museum[1718] (fig. 624) from
Yorkshire, mentioned by Nathorst in an early paper as probably a new
species of Anthrophyopsis, afforded good preparations of the cuticle (fig.
625) which revealed the existence of circular elevations on the outer walls
of the epidermal cells: these may explain the nature of some at least of the
supposed sporangia. The walls of the epidermal cells are straight. The name
Ctenis is applied to pinnate fronds which are probably Cycadean though we
have no evidence as to the nature of the stem or the reproductive organs.
Ctenis fronds are among the largest Cycadean leaves from Mesozoic floras;
in Ctenis hungarica Staub the frond is said to have reached a length of 2
met. and in other species the dimensions exceed those of most pinnate
leaves. The stout rachis bears linear or broad-oblong pinnae attached at a
wide angle and varying considerably in size and shape; the pinnae are
attached by the whole base which is usually broadened and decurrent but in
a few cases slightly contracted (e.g. C. Zeyschneri Rac.[1719]). For some
fronds bearing broad and basally narrowed segments Raciborski proposed
the name Ctenidiopsis in distinction from Euctenis which he applies to the
typical forms. The pinnae may be long and narrow reaching a length of over
12 cm., or short and broad: in some cases the frond would be more correctly
described as deeply pinnatisect; the apex of the segments is acute, bluntly
The genus Ctenis[1711] was founded on a piece of pinnate frond from the
Middle Jurassic rocks of the Yorkshire coast previously figured by Phillips
as Cycadites sulcicaulis. Lindley and Hutton regarded the plant as probably
Cycadean and proposed to apply the name Ctenis to all leaves having the
general characters of Cycadeae, but with ‘the veins connected by forks or
transverse bars.’ While many authors have accepted Ctenis as a Cycadean
genus, by others[1712] it has been placed among the Ferns, on the ground that
some small circular elevations on the lamina of the segments of certain
species are believed to be sori or sporangia. Since Ettingshausen[1713] and
Schenk[1714] first noticed this feature Raciborski[1715] has figured several
examples from Poland and Staub[1716] records similar circular bodies on a
Liassic Hungarian species. In no single instance have sporangia been found.
Nathorst[1717] proposed the designation Anthrophyopsis (because of the
resemblance of the lamina in form and venation to the leaves of the Fern
Anthrophyum) for some Rhaetic specimens from Scania, but as they were
subsequently found to be segments of a pinnate frond he adopted the name
Ctenis. An example in the Manchester Museum[1718] (fig. 624) from
Yorkshire, mentioned by Nathorst in an early paper as probably a new
species of Anthrophyopsis, afforded good preparations of the cuticle (fig.
625) which revealed the existence of circular elevations on the outer walls
of the epidermal cells: these may explain the nature of some at least of the
supposed sporangia. The walls of the epidermal cells are straight. The name
Ctenis is applied to pinnate fronds which are probably Cycadean though we
have no evidence as to the nature of the stem or the reproductive organs.
Ctenis fronds are among the largest Cycadean leaves from Mesozoic floras;
in Ctenis hungarica Staub the frond is said to have reached a length of 2
met. and in other species the dimensions exceed those of most pinnate
leaves. The stout rachis bears linear or broad-oblong pinnae attached at a
wide angle and varying considerably in size and shape; the pinnae are
attached by the whole base which is usually broadened and decurrent but in
a few cases slightly contracted (e.g. C. Zeyschneri Rac.[1719]). For some
fronds bearing broad and basally narrowed segments Raciborski proposed
the name Ctenidiopsis in distinction from Euctenis which he applies to the
typical forms. The pinnae may be long and narrow reaching a length of over
12 cm., or short and broad: in some cases the frond would be more correctly
described as deeply pinnatisect; the apex of the segments is acute, bluntly
Page 625
rounded or truncate. Several veins pass into the base of each pinna and
pursue a course approximately parallel to the edge of the lamina; a
characteristic feature is the occasional occurrence of oblique cross-
connexions between the veins. It is possible that in some species the pinnae
had spinous margins as in the pinnae of uncertain affinity figured by
Fontaine[1720] as Encephalartopsis nervosa from the Potomac series. Our
knowledge of the epidermal cells is very meagre: in the specimen
represented in fig. 625 the epidermal cells have straight walls and a central
papilla. The genus extends from Triassic to Upper Jurassic rocks.
Fig. 624. Ctenis sp. Single pinna. (Manchester Museum, No. 53.)
pursue a course approximately parallel to the edge of the lamina; a
characteristic feature is the occasional occurrence of oblique cross-
connexions between the veins. It is possible that in some species the pinnae
had spinous margins as in the pinnae of uncertain affinity figured by
Fontaine[1720] as Encephalartopsis nervosa from the Potomac series. Our
knowledge of the epidermal cells is very meagre: in the specimen
represented in fig. 625 the epidermal cells have straight walls and a central
papilla. The genus extends from Triassic to Upper Jurassic rocks.
Fig. 624. Ctenis sp. Single pinna. (Manchester Museum, No. 53.)
Page 626
Fig. 625. Ctenis sp. The epidermis of the pinna shown in fig. 624. A,
surface-view; p, papillae; s, stomata. B, side-view. (Manchester
Museum, No. 53.)
Ctenis lunzensis Stur.
This species, first recorded by Stur from the Lunz Upper Triassic flora,
has recently been examined by Krasser[1721] and compared with the Jurassic
species Ctenis sulcicaulis (Phill.) (= C. falcata Lind. and Hutt.) and C.
Potocki Rac. No figures or detailed descriptions have been published.
Ctenis fallax Nathorst.
This Scanian Rhaetic type[1722], including Anthrophyopsis crassinervis, A.
Nilssoni, and probably A. obovata Nath., is characterised by very large
obtusely pointed pinnae reaching at least 20 cm. in length and over 3 cm. in
breadth. The veins are often 2 mm. apart and form long polygonal meshes.
Nathorst figures small circular patches on the surface of the lamina.
surface-view; p, papillae; s, stomata. B, side-view. (Manchester
Museum, No. 53.)
Ctenis lunzensis Stur.
This species, first recorded by Stur from the Lunz Upper Triassic flora,
has recently been examined by Krasser[1721] and compared with the Jurassic
species Ctenis sulcicaulis (Phill.) (= C. falcata Lind. and Hutt.) and C.
Potocki Rac. No figures or detailed descriptions have been published.
Ctenis fallax Nathorst.
This Scanian Rhaetic type[1722], including Anthrophyopsis crassinervis, A.
Nilssoni, and probably A. obovata Nath., is characterised by very large
obtusely pointed pinnae reaching at least 20 cm. in length and over 3 cm. in
breadth. The veins are often 2 mm. apart and form long polygonal meshes.
Nathorst figures small circular patches on the surface of the lamina.
Page 627
Raciborski[1723], on slender evidence, refers a fragment from the Jurassic of
Cracow to this species.
Ctenis hungarica Staub.
A species[1724] characterised by very large fronds reaching 2 met., bearing
broad linear pinnae almost at right-angles and attached to the rachis by
decurrent bases, attaining a length of 21 cm. and a breadth at the base of the
lamina of 3·5 cm. and 4 cm. a short distance from the acute apex. The veins
are parallel to the edge of the lamina, but Staub does not appear to have
seen distinct anastomoses. It is not improbable that Staub’s species may be
identical with C. asplenioides (Ett.) from the Lias of Hungary, specimens of
which are preserved in the École des Mines, Paris.
Ctenis asplenioides (Ettingshausen).
This species was first described by Ettingshausen[1725] from Liassic strata
in Austria as Taeniopteris asplenioides and compared by him to large
simple fronds of Asplenium nidus but distinguished by a deeply dissected
lamina. Schenk[1726] found that the veins anastomose and adopted the name
Ctenis. In habit very similar to C. sulcicaulis, but the pinnae are much
broader, exceeding 4 cm., and the veins are 3–5 mm. apart. Only the basal
part of the segments is figured by Ettingshausen. Specimens in the École
des Mines, Paris, from Hungary have pinnae nearly 40 cm. long and 2·5
cm. in breadth, the parallel veins being connected by a few oblique
branches. Both Ettingshausen and Schenk speak of small circular sori on
the lower epidermis, though these are not figured nor were any sporangia
obtained. This species and other examples of large Ctenis fronds are
described by Raciborski from Lower Jurassic rocks in Poland. He figures
part of a leaf of C. Zeyschneri[1727] 40 cm. long bearing alternate pinnae
approximately 10 cm. long and nearly 4 cm. broad, characterised by obtuse
apices, a decurrent lamina, and anastomosing veins closer together (16–24
per 1 cm.) than those of C. asplenioides. In one Polish specimen, C.
remotinervis[1728], with pinnae 5 cm. broad the lamina is represented in the
upper part of the frond as continuous over the face of the rachis, and—if the
drawing is accurate—the frond in this respect differs from typical examples
of Ctenis and agrees with Nilssonia. A species of Ctenis with broad pinnae
is described by Yokoyama[1729] from the Jurassic of China as C. Kaneharai.
Cracow to this species.
Ctenis hungarica Staub.
A species[1724] characterised by very large fronds reaching 2 met., bearing
broad linear pinnae almost at right-angles and attached to the rachis by
decurrent bases, attaining a length of 21 cm. and a breadth at the base of the
lamina of 3·5 cm. and 4 cm. a short distance from the acute apex. The veins
are parallel to the edge of the lamina, but Staub does not appear to have
seen distinct anastomoses. It is not improbable that Staub’s species may be
identical with C. asplenioides (Ett.) from the Lias of Hungary, specimens of
which are preserved in the École des Mines, Paris.
Ctenis asplenioides (Ettingshausen).
This species was first described by Ettingshausen[1725] from Liassic strata
in Austria as Taeniopteris asplenioides and compared by him to large
simple fronds of Asplenium nidus but distinguished by a deeply dissected
lamina. Schenk[1726] found that the veins anastomose and adopted the name
Ctenis. In habit very similar to C. sulcicaulis, but the pinnae are much
broader, exceeding 4 cm., and the veins are 3–5 mm. apart. Only the basal
part of the segments is figured by Ettingshausen. Specimens in the École
des Mines, Paris, from Hungary have pinnae nearly 40 cm. long and 2·5
cm. in breadth, the parallel veins being connected by a few oblique
branches. Both Ettingshausen and Schenk speak of small circular sori on
the lower epidermis, though these are not figured nor were any sporangia
obtained. This species and other examples of large Ctenis fronds are
described by Raciborski from Lower Jurassic rocks in Poland. He figures
part of a leaf of C. Zeyschneri[1727] 40 cm. long bearing alternate pinnae
approximately 10 cm. long and nearly 4 cm. broad, characterised by obtuse
apices, a decurrent lamina, and anastomosing veins closer together (16–24
per 1 cm.) than those of C. asplenioides. In one Polish specimen, C.
remotinervis[1728], with pinnae 5 cm. broad the lamina is represented in the
upper part of the frond as continuous over the face of the rachis, and—if the
drawing is accurate—the frond in this respect differs from typical examples
of Ctenis and agrees with Nilssonia. A species of Ctenis with broad pinnae
is described by Yokoyama[1729] from the Jurassic of China as C. Kaneharai.
Page 628
Ctenis sulcicaulis (Phillips).
This type[1730] is more familiar under the name Ctenis falcata given to it
by Lindley[1731], but if we follow Lester Ward[1732] in strict observance of the
rule of priority, a course from which I have frequently deviated on the
ground of long usage, the less familiar designation must be adopted. Fronds
pinnate; long and tapered linear pinnae sometimes exceeding 12 cm. in
length and 1 cm. in breadth attached obliquely or almost at right-angles to a
fairly broad rachis (fig. 626). The lamina is broadest at the base and the
lower margin is strongly decurrent, tapering distally to an acute apex. The
parallel and frequently anastomosing veins diverge slightly in the basal
region of the pinnae. Though usually separate to the base, the laminae of
adjacent pinnae may be continuous as in a pinnatisect leaf[1733]. This species
is recorded also from North America, and fronds of similar habit are figured
by Fontaine[1734] from the Jurassic of Oregon as Ctenis orovillensis: a
fragment recorded from Jurassic rocks in Afghanistan as Ctenis sp. may
belong to C. sulcicaulis[1735].
Ctenis latifolia (Brongniart).
This species[1736], originally referred to Taeniopteris, was transferred to
Ctenis as the result of the discovery of anastomosing veins in the type-
specimen in the Oxford Museum. The segments are shorter and broader
than in C. sulcicaulis and very similar to those of C. orovillensis Font.
This type[1730] is more familiar under the name Ctenis falcata given to it
by Lindley[1731], but if we follow Lester Ward[1732] in strict observance of the
rule of priority, a course from which I have frequently deviated on the
ground of long usage, the less familiar designation must be adopted. Fronds
pinnate; long and tapered linear pinnae sometimes exceeding 12 cm. in
length and 1 cm. in breadth attached obliquely or almost at right-angles to a
fairly broad rachis (fig. 626). The lamina is broadest at the base and the
lower margin is strongly decurrent, tapering distally to an acute apex. The
parallel and frequently anastomosing veins diverge slightly in the basal
region of the pinnae. Though usually separate to the base, the laminae of
adjacent pinnae may be continuous as in a pinnatisect leaf[1733]. This species
is recorded also from North America, and fronds of similar habit are figured
by Fontaine[1734] from the Jurassic of Oregon as Ctenis orovillensis: a
fragment recorded from Jurassic rocks in Afghanistan as Ctenis sp. may
belong to C. sulcicaulis[1735].
Ctenis latifolia (Brongniart).
This species[1736], originally referred to Taeniopteris, was transferred to
Ctenis as the result of the discovery of anastomosing veins in the type-
specimen in the Oxford Museum. The segments are shorter and broader
than in C. sulcicaulis and very similar to those of C. orovillensis Font.
Page 629
Fig. 626. Ctenis sulcicaulis. (British Museum, V. 9012.)
Ctenis sp.
The pinna shown in fig. 624 from the Jurassic beds in Yorkshire[1737] is
interesting as one of the few examples of the preservation of the cuticular
membrane. The straight or curved walls of the epidermal cells agree with
those of recent Cycads except Stangeria, and each cell bears a large central
papilla that gives to the lamina the finely punctate appearance which has
been regarded as evidence of sporangia. The gaps in the cuticle probably
mark the position of sunken stomata.
PSEUDOCTENIS. Seward.
This genus[1738] was established for certain pinnate fronds agreeing in
habit with Ctenis sulcicaulis but distinguished by the almost complete
absence of any cross-connexions between the veins. Some of the forms with
Ctenis sp.
The pinna shown in fig. 624 from the Jurassic beds in Yorkshire[1737] is
interesting as one of the few examples of the preservation of the cuticular
membrane. The straight or curved walls of the epidermal cells agree with
those of recent Cycads except Stangeria, and each cell bears a large central
papilla that gives to the lamina the finely punctate appearance which has
been regarded as evidence of sporangia. The gaps in the cuticle probably
mark the position of sunken stomata.
PSEUDOCTENIS. Seward.
This genus[1738] was established for certain pinnate fronds agreeing in
habit with Ctenis sulcicaulis but distinguished by the almost complete
absence of any cross-connexions between the veins. Some of the forms with
Page 630
narrow pinnae closely resemble species of Zamites, the distinguishing
feature being the decurrent lower margin of the leaflets. Though such fronds
might not unreasonably be included in Ctenis, it is more convenient on the
analogy of the occasional occurrence of Glossopteris fronds with very few
anastomoses to employ a distinctive designation.
Fig. 627. Pseudoctenis eathiensis. (British Museum, No. V. 2744; ½ nat.
size.)
Pseudoctenis eathiensis (Richards).
Some of the specimens on which this species[1739] is founded were
originally figured by Miller[1740] from Upper Jurassic strata in Scotland and
afterwards named by Richards[1741] Zamites eathiensis. The general
appearance of the fronds is very like that of Ctenis sulcicaulis; the pinnae
vary in breadth from about 3 mm. to 1·5 cm.; they are attached at right-
angles or, in the apical region, may be almost parallel to the rachis. The
longest pinna recorded is 17 cm. and the lamina tapers to a slender apex; the
veins are parallel and occasionally forked, but cross-connexions are rare.
feature being the decurrent lower margin of the leaflets. Though such fronds
might not unreasonably be included in Ctenis, it is more convenient on the
analogy of the occasional occurrence of Glossopteris fronds with very few
anastomoses to employ a distinctive designation.
Fig. 627. Pseudoctenis eathiensis. (British Museum, No. V. 2744; ½ nat.
size.)
Pseudoctenis eathiensis (Richards).
Some of the specimens on which this species[1739] is founded were
originally figured by Miller[1740] from Upper Jurassic strata in Scotland and
afterwards named by Richards[1741] Zamites eathiensis. The general
appearance of the fronds is very like that of Ctenis sulcicaulis; the pinnae
vary in breadth from about 3 mm. to 1·5 cm.; they are attached at right-
angles or, in the apical region, may be almost parallel to the rachis. The
longest pinna recorded is 17 cm. and the lamina tapers to a slender apex; the
veins are parallel and occasionally forked, but cross-connexions are rare.
Page 631
The partially petrified rachis of one specimen showed hypodermal stereome
and some secretory canals as in recent Cycads. The specimen from Wealden
rocks near Hastings (fig. 627), originally described as Zamites sp.[1742], is
probably specifically identical with Pseudoctenis eathiensis. The South
African Wealden species, originally described by Tate as Palaeozamia
Rubidgei[1743], agrees closely with Pseudoctenis and is probably an example
of that genus. This type bears a close resemblance in the form of the frond
to Ctenophyllum grandifolium Font.[1744] and C. Wardi[1745] Font. from
American Trias and Jurassic rocks respectively. Pseudoctenis crassinervis
Sew.[1746] is another Scotch form with coarser veins.
A frond very similar in habit to P. eathiensis is represented by
Pseudoctenis ensiformis Halle[1747] from the Jurassic strata of Graham Land
originally referred by Nathorst to Pterophyllum. An examination of the
type-specimen in the Stockholm Museum revealed its resemblance to the
Scotch species P. eathiensis: a single anastomosis was noticed in one of the
pinnae. The broadly ensiform obtuse pinnae, reaching a length of 7 cm.
with a maximum breadth of 3 cm. at their expanded bases, vary in breadth
and are attached at right-angles to a slender rachis. The veins, 1–1·5 mm.
apart, are parallel and strong. The varying breadth of the pinnae irrespective
of their position on the rachis is a distinctive feature. Halle draws attention
to a resemblance of this Antarctic species to Ctenophyllum latifolium Font.
a Potomac type referred by Berry[1748] to the genus Ctenopsis on the rather
slender ground that the veins are arranged in pairs. Berry in a footnote
expresses the opinion that Ctenopsis is very closely related to or possibly
identical with Pseudoctenis.
If the bases of the pinnae in the specimen of P. ensiformis figured by
Halle are complete, as they appear to be, the frond agrees very closely with
Pterophyllum Carterianum Old. and Morr.[1749] from India. A comparison of
the Rajmahal specimen with Halle’s figure leads me to regard the two
fronds as probably identical. The veins in the Indian species, which should
also be referred to Pseudoctenis, are prominent and from ·5 to 1 mm. apart;
the base of the lamina is slightly broadened and the veins curve downwards
towards the rachis in the lower decurrent portion. The other Indian type,
Pterophyllum Morrisianum[1750], with which Halle compares his species is,
however, not a Pseudoctenis but should be included in Nilssonia and is
probably identical with Pterophyllum princeps Old. and Morr.
and some secretory canals as in recent Cycads. The specimen from Wealden
rocks near Hastings (fig. 627), originally described as Zamites sp.[1742], is
probably specifically identical with Pseudoctenis eathiensis. The South
African Wealden species, originally described by Tate as Palaeozamia
Rubidgei[1743], agrees closely with Pseudoctenis and is probably an example
of that genus. This type bears a close resemblance in the form of the frond
to Ctenophyllum grandifolium Font.[1744] and C. Wardi[1745] Font. from
American Trias and Jurassic rocks respectively. Pseudoctenis crassinervis
Sew.[1746] is another Scotch form with coarser veins.
A frond very similar in habit to P. eathiensis is represented by
Pseudoctenis ensiformis Halle[1747] from the Jurassic strata of Graham Land
originally referred by Nathorst to Pterophyllum. An examination of the
type-specimen in the Stockholm Museum revealed its resemblance to the
Scotch species P. eathiensis: a single anastomosis was noticed in one of the
pinnae. The broadly ensiform obtuse pinnae, reaching a length of 7 cm.
with a maximum breadth of 3 cm. at their expanded bases, vary in breadth
and are attached at right-angles to a slender rachis. The veins, 1–1·5 mm.
apart, are parallel and strong. The varying breadth of the pinnae irrespective
of their position on the rachis is a distinctive feature. Halle draws attention
to a resemblance of this Antarctic species to Ctenophyllum latifolium Font.
a Potomac type referred by Berry[1748] to the genus Ctenopsis on the rather
slender ground that the veins are arranged in pairs. Berry in a footnote
expresses the opinion that Ctenopsis is very closely related to or possibly
identical with Pseudoctenis.
If the bases of the pinnae in the specimen of P. ensiformis figured by
Halle are complete, as they appear to be, the frond agrees very closely with
Pterophyllum Carterianum Old. and Morr.[1749] from India. A comparison of
the Rajmahal specimen with Halle’s figure leads me to regard the two
fronds as probably identical. The veins in the Indian species, which should
also be referred to Pseudoctenis, are prominent and from ·5 to 1 mm. apart;
the base of the lamina is slightly broadened and the veins curve downwards
towards the rachis in the lower decurrent portion. The other Indian type,
Pterophyllum Morrisianum[1750], with which Halle compares his species is,
however, not a Pseudoctenis but should be included in Nilssonia and is
probably identical with Pterophyllum princeps Old. and Morr.
Page 632
Pseudoctenis Lanei Thomas.
This species[1751], recently described from Middle Jurassic beds at
Marske, Yorkshire, has narrower linear lanceolate pinnae. The linear pinnae
reach a length of 10 cm. and a breadth of 9 mm. The veins are numerous, 10
in a breadth of 6 mm., and only one cross-vein was noticed. In the decurrent
lower edge of the laminae the fronds are identical with Ctenis sulcicaulis. A
very good example of this species[1752] in the York Museum is reproduced by
Mr Thomas in his account of Cleveland Jurassic plants.
Pseudoctenis Balli (Feistmantel).
A species described originally by Feistmantel[1753] as Anomozamites Balli
from the Barakar group of the Damuda series and afterwards transferred to
the genus Platypterygium, characterised by broadly linear segments of
unequal breadth attached obliquely or at right-angles to a slender rachis.
The apices of the segments though usually imperfect appear to be truncate;
the bases of the pinnae are decurrent by their lower edge. The veins are
approximately 3 per millimetre; they are generally forked at the base and in
one or two places show cross-connexions. In the middle of the frond the
narrow rachis is exposed but in the apical region it is covered by the
laminae. The occurrence of two divergent pinnae at the apex of the frond is
a feature met with also in Ctenis sulcicaulis. This description is based on an
examination of the specimens figured by Feistmantel.
III. Cycadean Fronds which cannot be assigned to a family-
position.
SPHENOZAMITES. Brongniart.
This name was proposed by Brongniart[1754] as a subgenus of Otozamites
denoting pinnate fronds bearing leaflets without an auriculate base: he
suggested that the subgenus might eventually be raised to generic rank and
this was done by Zigno[1755] though in too wide a sense. In the case of
Otozamites Beani (Lind. and Hutt.), quoted by Brongniart in illustration of
Sphenozamites, the latter designation is inapplicable as the pinnae are
auriculate. Another species, Zamites undulatus Sternb., to which Brongniart
applied his new subgeneric term, is probably identical with Otozamites
acuminatus (L. and H.)[1756].
This species[1751], recently described from Middle Jurassic beds at
Marske, Yorkshire, has narrower linear lanceolate pinnae. The linear pinnae
reach a length of 10 cm. and a breadth of 9 mm. The veins are numerous, 10
in a breadth of 6 mm., and only one cross-vein was noticed. In the decurrent
lower edge of the laminae the fronds are identical with Ctenis sulcicaulis. A
very good example of this species[1752] in the York Museum is reproduced by
Mr Thomas in his account of Cleveland Jurassic plants.
Pseudoctenis Balli (Feistmantel).
A species described originally by Feistmantel[1753] as Anomozamites Balli
from the Barakar group of the Damuda series and afterwards transferred to
the genus Platypterygium, characterised by broadly linear segments of
unequal breadth attached obliquely or at right-angles to a slender rachis.
The apices of the segments though usually imperfect appear to be truncate;
the bases of the pinnae are decurrent by their lower edge. The veins are
approximately 3 per millimetre; they are generally forked at the base and in
one or two places show cross-connexions. In the middle of the frond the
narrow rachis is exposed but in the apical region it is covered by the
laminae. The occurrence of two divergent pinnae at the apex of the frond is
a feature met with also in Ctenis sulcicaulis. This description is based on an
examination of the specimens figured by Feistmantel.
III. Cycadean Fronds which cannot be assigned to a family-
position.
SPHENOZAMITES. Brongniart.
This name was proposed by Brongniart[1754] as a subgenus of Otozamites
denoting pinnate fronds bearing leaflets without an auriculate base: he
suggested that the subgenus might eventually be raised to generic rank and
this was done by Zigno[1755] though in too wide a sense. In the case of
Otozamites Beani (Lind. and Hutt.), quoted by Brongniart in illustration of
Sphenozamites, the latter designation is inapplicable as the pinnae are
auriculate. Another species, Zamites undulatus Sternb., to which Brongniart
applied his new subgeneric term, is probably identical with Otozamites
acuminatus (L. and H.)[1756].
Page 633
Although the distinction between Sphenozamites and Otozamites is often
ill defined the former name may be conveniently adopted for pinnate fronds
similar to those of Zamia Skinneri and some species of Encephalartos
characterised by leaflets of an asymmetrical, obovate, or rhomboidal form
with a contracted or cuneate base and numerous branched divergent veins.
Nothing is known of the structure or reproductive organs of Sphenozamites,
and the genus, though serving a useful descriptive purpose, is founded
solely on form, and in the absence of other data it would be rash to assume
that its use implies close natural affinity. In the case of many other genera
of Cycadean fronds there is additional evidence of relationship, but this is
not the case with Sphenozamites. The pinnae resemble those of such recent
Cycadean fronds as Zamia Skinneri and Z. muricata. The genus ranges from
Lower Permian to Jurassic rocks.
Sphenozamites Rochei Renault.
This species[1757], from the Lower Permian of the Autun district, is
founded on a pinnate frond bearing alternate pinnae, 2·5 × 1 cm., with an
asymmetrical oblong lamina attached obliquely near the edge of the rachis
with a cuneate base slightly decurrent below and a broadly rounded apex;
the veins dichotomise once or twice as they diverge from the narrow base
(fig. 628). The pinnae resemble the leaflets of Noeggerathia foliosa Sternb.
and are similar in shape to those of the Jurassic species Sphenozamites
Geylerianus Zig.
Sphenozamites Belli Seward.
This Middle Jurassic species from Stonesfield[1758] is founded on detached
pinnae possibly identical with a specimen figured by Buckman as ?Naiadea
obtusa[1759]. The pinnae are wedge-shaped, tapering gradually to an acute
apex and attached by a narrow base: the leaflet shown in fig. 629 is 9 cm.
long; the veins are numerous and more divergent than in some leaves of
similar form referred to the genus Podozamites. With this species may be
compared several Italian Jurassic specimens described by Zigno[1760] as four
distinct species but more appropriately assigned to a single type S.
Geylerianus. An examination of Zigno’s fronds in the Padua Museum,
which he named S. Rossii, leads me to regard the irregularly serrate edge of
the pinnae as the result of tearing of an originally entire lamina and to
ill defined the former name may be conveniently adopted for pinnate fronds
similar to those of Zamia Skinneri and some species of Encephalartos
characterised by leaflets of an asymmetrical, obovate, or rhomboidal form
with a contracted or cuneate base and numerous branched divergent veins.
Nothing is known of the structure or reproductive organs of Sphenozamites,
and the genus, though serving a useful descriptive purpose, is founded
solely on form, and in the absence of other data it would be rash to assume
that its use implies close natural affinity. In the case of many other genera
of Cycadean fronds there is additional evidence of relationship, but this is
not the case with Sphenozamites. The pinnae resemble those of such recent
Cycadean fronds as Zamia Skinneri and Z. muricata. The genus ranges from
Lower Permian to Jurassic rocks.
Sphenozamites Rochei Renault.
This species[1757], from the Lower Permian of the Autun district, is
founded on a pinnate frond bearing alternate pinnae, 2·5 × 1 cm., with an
asymmetrical oblong lamina attached obliquely near the edge of the rachis
with a cuneate base slightly decurrent below and a broadly rounded apex;
the veins dichotomise once or twice as they diverge from the narrow base
(fig. 628). The pinnae resemble the leaflets of Noeggerathia foliosa Sternb.
and are similar in shape to those of the Jurassic species Sphenozamites
Geylerianus Zig.
Sphenozamites Belli Seward.
This Middle Jurassic species from Stonesfield[1758] is founded on detached
pinnae possibly identical with a specimen figured by Buckman as ?Naiadea
obtusa[1759]. The pinnae are wedge-shaped, tapering gradually to an acute
apex and attached by a narrow base: the leaflet shown in fig. 629 is 9 cm.
long; the veins are numerous and more divergent than in some leaves of
similar form referred to the genus Podozamites. With this species may be
compared several Italian Jurassic specimens described by Zigno[1760] as four
distinct species but more appropriately assigned to a single type S.
Geylerianus. An examination of Zigno’s fronds in the Padua Museum,
which he named S. Rossii, leads me to regard the irregularly serrate edge of
the pinnae as the result of tearing of an originally entire lamina and to
Page 634
compare the specimens with Otozamites Beani (L. and
H.). An imperfect ovoid pinna recalling S. Belli is
figured by Newberry from the Rhaetic of Honduras as
Sphenozamites robustus[1761]. A French Upper Jurassic
species figured by Saporta as Sphenozamites latifolius
bears a very close resemblance in the form of the
leaflets to the Wealden plant Sewardia latifolia[1762].
Kurtz records the occurrence of Sphenozamites, S.
Geinitzianus, from Rhaetic strata in Argentina[1763], but
I have not seen any figures of this species.
Fig. 628.
Sphenozamites
Rochei. (After
Renault; nat.
size.)
Fig. 629. Sphenozamites Belli. (Oxford Museum; nat. size.)
PLAGIOZAMITES. Zeiller.
The name Plagiozamites was proposed by Zeiller[1764] for some pinnate
fronds and detached leaflets from the Stephanian of Commentry and the
Lower Permian of the Vosges. The better preservation of the Vosges
material enabled him to recognise certain features which led to the
substitution of Plagiozamites for Zamites, the name originally employed by
Renault for the Commentry specimens. Plagiozamites bears a superficial
resemblance to Zamites and Otozamites and differs but little from
Sphenozamites and Noeggerathia; it stands for pinnate fronds bearing ovate
H.). An imperfect ovoid pinna recalling S. Belli is
figured by Newberry from the Rhaetic of Honduras as
Sphenozamites robustus[1761]. A French Upper Jurassic
species figured by Saporta as Sphenozamites latifolius
bears a very close resemblance in the form of the
leaflets to the Wealden plant Sewardia latifolia[1762].
Kurtz records the occurrence of Sphenozamites, S.
Geinitzianus, from Rhaetic strata in Argentina[1763], but
I have not seen any figures of this species.
Fig. 628.
Sphenozamites
Rochei. (After
Renault; nat.
size.)
Fig. 629. Sphenozamites Belli. (Oxford Museum; nat. size.)
PLAGIOZAMITES. Zeiller.
The name Plagiozamites was proposed by Zeiller[1764] for some pinnate
fronds and detached leaflets from the Stephanian of Commentry and the
Lower Permian of the Vosges. The better preservation of the Vosges
material enabled him to recognise certain features which led to the
substitution of Plagiozamites for Zamites, the name originally employed by
Renault for the Commentry specimens. Plagiozamites bears a superficial
resemblance to Zamites and Otozamites and differs but little from
Sphenozamites and Noeggerathia; it stands for pinnate fronds bearing ovate
Page 635
pinnae with a sub-amplexicaul oblique attachment to the rachis as is clearly
shown in the species P. Planchardi (Ren.)[1765]. In the case of Palaeozoic
fronds assigned to the Cycadophyta on the ground of the resemblance of
their pinnae to those of undoubted Cycadean species, it is particularly
important to recognise the fact that decisive evidence as to systematic
position is lacking. We know nothing of the stem, the reproductive organs,
or the epidermal and stomatal characters of Plagiozamites, and it is by no
means certain that the genus is a true representative of the group in which it
is provisionally included.
Plagiozamites Planchardi (Renault).
Fronds pinnate; pinnae ovate-lanceolate reaching 5 cm. in length and 1·6
cm. in breadth, inserted obliquely on the rachis, but not along a line parallel
to the long axis of the rachis as in Zamites, and partially embracing it: the
edge of the lamina is finely denticulate; veins slightly divergent and
occasionally branched. The leaflets are narrow and more acute than those of
Noeggerathia and Sphenozamites Rochei Ren. Plagiozamites is recorded
from the Stephanian of Commentry, the Coal Measures of Manchuria[1766],
and the Lower Permian of the Vosges. Renault described six species of
Zamites from Commentry all, except Z. carbonarius, based on detached
pinnae. The type-specimen of Z. carbonarius consists of a piece of stout
rachis bearing ovate acute pinnae, 2·2 × 1 cm. Potonié[1767], who refers a
piece of pinnate frond from the Permian of Thuringia to Z. carbonarius,
includes the other species of Renault under that name. Whether or not the
differences in the venation and form of the pinnae are of specific
significance cannot be definitely settled without better material, but the
important point is that these Permo-Carboniferous fronds are sufficiently
distinct from Zamites to be placed in a separate genus. Plagiozamites
carbonarius is recorded also by Zalessky[1768] from the Permian of
Manchuria though the examples figured do not afford satisfactory evidence
of the mode of insertion of the segments on the rachis. P. Planchardi has
recently been recorded from the Coal Measures of Maryland; the discovery
is interesting both on phytogeographical grounds and as the first
satisfactory record of a Palaeozoic Cycadophyte from North America[1769].
Cycadorachis. Saporta.
shown in the species P. Planchardi (Ren.)[1765]. In the case of Palaeozoic
fronds assigned to the Cycadophyta on the ground of the resemblance of
their pinnae to those of undoubted Cycadean species, it is particularly
important to recognise the fact that decisive evidence as to systematic
position is lacking. We know nothing of the stem, the reproductive organs,
or the epidermal and stomatal characters of Plagiozamites, and it is by no
means certain that the genus is a true representative of the group in which it
is provisionally included.
Plagiozamites Planchardi (Renault).
Fronds pinnate; pinnae ovate-lanceolate reaching 5 cm. in length and 1·6
cm. in breadth, inserted obliquely on the rachis, but not along a line parallel
to the long axis of the rachis as in Zamites, and partially embracing it: the
edge of the lamina is finely denticulate; veins slightly divergent and
occasionally branched. The leaflets are narrow and more acute than those of
Noeggerathia and Sphenozamites Rochei Ren. Plagiozamites is recorded
from the Stephanian of Commentry, the Coal Measures of Manchuria[1766],
and the Lower Permian of the Vosges. Renault described six species of
Zamites from Commentry all, except Z. carbonarius, based on detached
pinnae. The type-specimen of Z. carbonarius consists of a piece of stout
rachis bearing ovate acute pinnae, 2·2 × 1 cm. Potonié[1767], who refers a
piece of pinnate frond from the Permian of Thuringia to Z. carbonarius,
includes the other species of Renault under that name. Whether or not the
differences in the venation and form of the pinnae are of specific
significance cannot be definitely settled without better material, but the
important point is that these Permo-Carboniferous fronds are sufficiently
distinct from Zamites to be placed in a separate genus. Plagiozamites
carbonarius is recorded also by Zalessky[1768] from the Permian of
Manchuria though the examples figured do not afford satisfactory evidence
of the mode of insertion of the segments on the rachis. P. Planchardi has
recently been recorded from the Coal Measures of Maryland; the discovery
is interesting both on phytogeographical grounds and as the first
satisfactory record of a Palaeozoic Cycadophyte from North America[1769].
Cycadorachis. Saporta.
Page 636
The employment of this generic name may serve a useful purpose if used
for specimens, whether preserved as petrifactions or impressions, believed
to be portions of Cycadean frond-axes, but which in the absence of pinnae
cannot be assigned to one of the recognised genera of fronds. Saporta[1770]
describes two species from Kimmeridgian beds in France, Cycadorachis
abscissa and C. armata: the first may be the winged base of a Cycadean
petiole, but it agrees equally well with the broad base of an Osmundaceous
leaf and should not be referred to a genus implying affinity with a particular
class. The other species, C. armata, is probably a piece of a spinous axis
like that of the Wealden plant Sewardia latifolia (Sap.). A fragment figured
by Fliche and Bleicher[1771] from the Jurassic of Nancy as C. tuberculata is
another example of a fossil which cannot be referred with any certainty to
the Cycads.
Dr Stopes[1772], inadvertently overlooking the previous institution of
Cycadorachis, has recently proposed the name Cycadeorachis for pinnately
branched rachises of Cycadean fronds which, ‘while indicating the general
character of the frond, do not show the shape of the pinnae well enough to
be associated with any of the many foliage-genera.’
for specimens, whether preserved as petrifactions or impressions, believed
to be portions of Cycadean frond-axes, but which in the absence of pinnae
cannot be assigned to one of the recognised genera of fronds. Saporta[1770]
describes two species from Kimmeridgian beds in France, Cycadorachis
abscissa and C. armata: the first may be the winged base of a Cycadean
petiole, but it agrees equally well with the broad base of an Osmundaceous
leaf and should not be referred to a genus implying affinity with a particular
class. The other species, C. armata, is probably a piece of a spinous axis
like that of the Wealden plant Sewardia latifolia (Sap.). A fragment figured
by Fliche and Bleicher[1771] from the Jurassic of Nancy as C. tuberculata is
another example of a fossil which cannot be referred with any certainty to
the Cycads.
Dr Stopes[1772], inadvertently overlooking the previous institution of
Cycadorachis, has recently proposed the name Cycadeorachis for pinnately
branched rachises of Cycadean fronds which, ‘while indicating the general
character of the frond, do not show the shape of the pinnae well enough to
be associated with any of the many foliage-genera.’
Page 637
Page 638
LIST OF WORKS REFERRED TO IN THE
TEXT
(Volumes III. and IV.)
[With a few exceptions this list does not include books and papers
given in the Bibliographies in volumes I. and II.]
The following are some of the Bibliographies which students will find
useful for additional references:—Geological Literature added to the
Geological Society’s Library, published from time to time by the Society;
Prof. Zeiller’s lists in the ‘Revue Générale de Botanique’ (Paris); lists given
by Arber in the ‘Progressus Rei Botanicae’ (Leiden), vol. i. Heft i. p. 218,
1907; Jongman’s ‘Die Palaeobotanische Literatur’ (Jena), 1910–13; also the
International Catalogue of Scientific Literature (Botany and Geology). For
the Literature dealing with Cretaceous plants the student should refer to Dr
Marie Stopes’ ‘Cretaceous Flora’ i. and ii. (British Museum Catalogues,
1913, 1915).
The dates of books published in parts given in the footnotes to this
volume are as a rule those of the concluding part. For the dates of separate
parts of books relating to Palaeozoic floras the student is referred to Prof.
Zeiller’s valuable list at the end of the ‘Flore Fossile du Bassin Houiller de
Valenciennes.’ Useful bibliographies of the writings of Saporta, Heer, and
Ettingshausen have been compiled by Zeiller (96), Malloizel and Zeiller
(N.D.), and Krasser (97).
Aase, Hannah C. (15) Vascular anatomy of the megasporophylls of
Conifers. Botanical Gazette, vol. lx. p. 277.
Affourtit, M. F. A. and H. C. C. La Rivière. (15) On the ribbing of the
seeds of Ginkgo. Annals of Botany, vol. xxix. p. 591.
Andersson, J. G. (10) Die Veränderungen des Klimas seit dem Maximum
der letzten Eiszeit. (Collection of papers published by the Int. Geol.
Congress; edited by J. G. Andersson.) Stockholm.
Andrews, E. B. (75) Descriptions of Fossil Plants from the Coal Measures
of Ohio. Geol. Surv. Ohio.
TEXT
(Volumes III. and IV.)
[With a few exceptions this list does not include books and papers
given in the Bibliographies in volumes I. and II.]
The following are some of the Bibliographies which students will find
useful for additional references:—Geological Literature added to the
Geological Society’s Library, published from time to time by the Society;
Prof. Zeiller’s lists in the ‘Revue Générale de Botanique’ (Paris); lists given
by Arber in the ‘Progressus Rei Botanicae’ (Leiden), vol. i. Heft i. p. 218,
1907; Jongman’s ‘Die Palaeobotanische Literatur’ (Jena), 1910–13; also the
International Catalogue of Scientific Literature (Botany and Geology). For
the Literature dealing with Cretaceous plants the student should refer to Dr
Marie Stopes’ ‘Cretaceous Flora’ i. and ii. (British Museum Catalogues,
1913, 1915).
The dates of books published in parts given in the footnotes to this
volume are as a rule those of the concluding part. For the dates of separate
parts of books relating to Palaeozoic floras the student is referred to Prof.
Zeiller’s valuable list at the end of the ‘Flore Fossile du Bassin Houiller de
Valenciennes.’ Useful bibliographies of the writings of Saporta, Heer, and
Ettingshausen have been compiled by Zeiller (96), Malloizel and Zeiller
(N.D.), and Krasser (97).
Aase, Hannah C. (15) Vascular anatomy of the megasporophylls of
Conifers. Botanical Gazette, vol. lx. p. 277.
Affourtit, M. F. A. and H. C. C. La Rivière. (15) On the ribbing of the
seeds of Ginkgo. Annals of Botany, vol. xxix. p. 591.
Andersson, J. G. (10) Die Veränderungen des Klimas seit dem Maximum
der letzten Eiszeit. (Collection of papers published by the Int. Geol.
Congress; edited by J. G. Andersson.) Stockholm.
Andrews, E. B. (75) Descriptions of Fossil Plants from the Coal Measures
of Ohio. Geol. Surv. Ohio.
Page 639
Antevs, E. (14) Lepidopteris Ottonis (Göpp.) Schimp. and Anthotithus
Zeilleri Nath. K. Svensk. Vetenskapsakad. Hand. Bd. li. No. 7.
—— (142) The Swedish Species of Ptilozamites Nath. Ibid. Bd. li. No. 10.
Arber, Agnes. (See also Robertson, A.) (10) On the structure of the
Palaeozoic seed Mitrospermum compressum (Will.). Ann. Bot. vol.
xxiv. p. 491.
—— (14) A note on Trigonocarpus. Ibid. vol. xxviii. p. 195.
Arber, E. A. Newell. (02) Notes on the Binney collection of Coal-Measure
Plants. Pt. iii. The type-specimens of Lyginodendron oldhamium
(Binney). Proc. Camb. Phil. Soc. vol. xi. pt. iv. p. 281.
—— (03) On the roots of Medullosa anglica. Ann. Bot. vol. xvii. p. 425.
—— (032) Discussion on Dr Kurtz’s paper (1903). Quart. Journ. Geol. Soc.
vol. lix. p. 26.
—— (04) Cupressinoxylon Hookeri sp. nov. a large silicified tree from
Tasmania. Geol. Mag. [v], vol. i. p. 7.
—— (05) On some new species of Lagenostoma, a type of Pteridospermous
seed from the Coal Measures. Proc. R. Soc. vol. lxxi. B, p. 245.
—— (07) On Triassic species of the genera Zamites and Pterophyllum,
types of fronds belonging to the Cycadophyta. Trans. Linn. Soc. vol.
vii. pt. vii. p. 109.
—— (08) On a new Pteridosperm possessing the Sphenopteris type of
foliage. Ann. Bot. vol. xxii. p. 57.
—— (09) On the Fossil Plants of the Waldershare and Fredville series of
the Kent Coalfield. Quart. Journ. Geol. Soc. vol. lxv. p. 21.
—— (092) On the affinities of the Triassic plant Yuccites vogesiacus
Schimp. and Moug. Geol. Mag. [v], vol. vi. p. 11.
—— (12) On Psygmophyllum majus sp. nov. from the Lower Carboniferous
rocks of Newfoundland, together with a Revision of the genus and
Remarks on its affinities. Trans. Linn. Soc. vol. vii. p. 391.
—— (122) Fossil Plants from the Kent Coalfield. Geol. Mag. [v], vol. ix. p.
97.
—— (13) A preliminary note on the Fossil Plants of the Mount Potts beds,
New Zealand, collected by Mr D. G. Lillie, Biologist to Capt. Scott’s
Antarctic Expedition in the “Terra Nova.” Proc. R. Soc. vol. lxxxvi. p.
344.
—— (132) The structure of Dadoxylon Kayi. Quart. Journ. Geol. Soc. vol.
lxix. p. 454.
Zeilleri Nath. K. Svensk. Vetenskapsakad. Hand. Bd. li. No. 7.
—— (142) The Swedish Species of Ptilozamites Nath. Ibid. Bd. li. No. 10.
Arber, Agnes. (See also Robertson, A.) (10) On the structure of the
Palaeozoic seed Mitrospermum compressum (Will.). Ann. Bot. vol.
xxiv. p. 491.
—— (14) A note on Trigonocarpus. Ibid. vol. xxviii. p. 195.
Arber, E. A. Newell. (02) Notes on the Binney collection of Coal-Measure
Plants. Pt. iii. The type-specimens of Lyginodendron oldhamium
(Binney). Proc. Camb. Phil. Soc. vol. xi. pt. iv. p. 281.
—— (03) On the roots of Medullosa anglica. Ann. Bot. vol. xvii. p. 425.
—— (032) Discussion on Dr Kurtz’s paper (1903). Quart. Journ. Geol. Soc.
vol. lix. p. 26.
—— (04) Cupressinoxylon Hookeri sp. nov. a large silicified tree from
Tasmania. Geol. Mag. [v], vol. i. p. 7.
—— (05) On some new species of Lagenostoma, a type of Pteridospermous
seed from the Coal Measures. Proc. R. Soc. vol. lxxi. B, p. 245.
—— (07) On Triassic species of the genera Zamites and Pterophyllum,
types of fronds belonging to the Cycadophyta. Trans. Linn. Soc. vol.
vii. pt. vii. p. 109.
—— (08) On a new Pteridosperm possessing the Sphenopteris type of
foliage. Ann. Bot. vol. xxii. p. 57.
—— (09) On the Fossil Plants of the Waldershare and Fredville series of
the Kent Coalfield. Quart. Journ. Geol. Soc. vol. lxv. p. 21.
—— (092) On the affinities of the Triassic plant Yuccites vogesiacus
Schimp. and Moug. Geol. Mag. [v], vol. vi. p. 11.
—— (12) On Psygmophyllum majus sp. nov. from the Lower Carboniferous
rocks of Newfoundland, together with a Revision of the genus and
Remarks on its affinities. Trans. Linn. Soc. vol. vii. p. 391.
—— (122) Fossil Plants from the Kent Coalfield. Geol. Mag. [v], vol. ix. p.
97.
—— (13) A preliminary note on the Fossil Plants of the Mount Potts beds,
New Zealand, collected by Mr D. G. Lillie, Biologist to Capt. Scott’s
Antarctic Expedition in the “Terra Nova.” Proc. R. Soc. vol. lxxxvi. p.
344.
—— (132) The structure of Dadoxylon Kayi. Quart. Journ. Geol. Soc. vol.
lxix. p. 454.
Page 640
—— (14) A Revision of the Seed impressions of the British Coal Measures.
Ann. Bot. vol. xxviii. p. 81.
—— (142) On the Fossil Flora of the Kent Coalfield. Quart. Journ. Geol.
Soc. vol. lxx. p. 54.
Arber, E. A. Newell and J. Parkin. (07) On the origin of Angiosperms.
Journ. Linn. Soc. vol. xxxviii. p. 29.
—— (08) Studies on the Evolution of the Angiosperms. Ann. Bot. vol. xxii.
p. 489.
Arnoldi, W. (01) Beiträge zur Morphologie einiger Gymnospermen. Bull.
Nat. Moscow, No. 4, 1900.
Bailey, I. W. (09) The structure of the wood in the Pineae. Bot. Gaz. vol.
xlviii. p. 47.
—— (11) A Cretaceous Pityoxylon with marginal tracheids. Ann. Bot. vol.
xxv. p. 315.
Baily, W. H. (69) Notice of Plant-remains from Beds interstratified with the
Basalts in the county of Antrim. Quart. Journ. Geol. Soc. vol. xxv. p.
357.
Bain, F. and Sir W. Dawson. (85) Notes on the Geology and Fossil Flora of
Prince Edward Island. Canadian Rec. Sci. vol. i. (1884–85) p. 154.
Baker, R. T. and H. C. Smith. (10) Research of the Pines on Australia. Dpt.
Public Instruction, Tech. Educ. Ser. No. 16. Sydney.
Bancroft, Nellie. (13) On some Indian Jurassic Gymnosperms and
Rhexoxylon africanum, a new Medullosan stem. Trans. Linn. Soc. vol.
viii. pt. ii. p. 69.
—— (14) Pteridosperm Anatomy and its relation to that of the Cycads. New
Phyt. vol. xiii. p. 41.
Barber, C. A. (92) On the nature and development of the corky
excrescences on stems of Zanthoxylum. Ann. Bot. vol. vi. p. 155.
—— (98) Cupressionoxylon vectense; a fossil Conifer from the Lower
Greensand of Shanklin, in the Isle of Wight. Ann. Bot. vol. xii. p. 329.
Bartholin, C. T. (94) Nogle i den bornholmske Juraformation
forekommende Planteforsteninger. Bot. Tidskrift (Copenhagen), Bd.
xix. p. 87.
Bartlett, A. W. (13) Note on the occurrence of an abnormal bisporangiate
strobilus of Larix europaea DC. Ann. Bot. vol. xxvii. p. 575.
Bassler, H. (16) A Cycadophyte from the North American Coal Measures.
Amer. Journ. Sci. vol. xlii. p. 21.
Ann. Bot. vol. xxviii. p. 81.
—— (142) On the Fossil Flora of the Kent Coalfield. Quart. Journ. Geol.
Soc. vol. lxx. p. 54.
Arber, E. A. Newell and J. Parkin. (07) On the origin of Angiosperms.
Journ. Linn. Soc. vol. xxxviii. p. 29.
—— (08) Studies on the Evolution of the Angiosperms. Ann. Bot. vol. xxii.
p. 489.
Arnoldi, W. (01) Beiträge zur Morphologie einiger Gymnospermen. Bull.
Nat. Moscow, No. 4, 1900.
Bailey, I. W. (09) The structure of the wood in the Pineae. Bot. Gaz. vol.
xlviii. p. 47.
—— (11) A Cretaceous Pityoxylon with marginal tracheids. Ann. Bot. vol.
xxv. p. 315.
Baily, W. H. (69) Notice of Plant-remains from Beds interstratified with the
Basalts in the county of Antrim. Quart. Journ. Geol. Soc. vol. xxv. p.
357.
Bain, F. and Sir W. Dawson. (85) Notes on the Geology and Fossil Flora of
Prince Edward Island. Canadian Rec. Sci. vol. i. (1884–85) p. 154.
Baker, R. T. and H. C. Smith. (10) Research of the Pines on Australia. Dpt.
Public Instruction, Tech. Educ. Ser. No. 16. Sydney.
Bancroft, Nellie. (13) On some Indian Jurassic Gymnosperms and
Rhexoxylon africanum, a new Medullosan stem. Trans. Linn. Soc. vol.
viii. pt. ii. p. 69.
—— (14) Pteridosperm Anatomy and its relation to that of the Cycads. New
Phyt. vol. xiii. p. 41.
Barber, C. A. (92) On the nature and development of the corky
excrescences on stems of Zanthoxylum. Ann. Bot. vol. vi. p. 155.
—— (98) Cupressionoxylon vectense; a fossil Conifer from the Lower
Greensand of Shanklin, in the Isle of Wight. Ann. Bot. vol. xii. p. 329.
Bartholin, C. T. (94) Nogle i den bornholmske Juraformation
forekommende Planteforsteninger. Bot. Tidskrift (Copenhagen), Bd.
xix. p. 87.
Bartlett, A. W. (13) Note on the occurrence of an abnormal bisporangiate
strobilus of Larix europaea DC. Ann. Bot. vol. xxvii. p. 575.
Bassler, H. (16) A Cycadophyte from the North American Coal Measures.
Amer. Journ. Sci. vol. xlii. p. 21.
Page 641
Bayer, A. (08) Zur Deutung der weiblichen Blüten der Cupressineen nebst
Bemerkungen über Cryptomeria. Beiheft Bot. Cent. Bd. xxiii. Abt. i. p.
27.
Beissner, L. (91) Handbuch der Nadelholzkunde. Berlin.
Bennett, J. J. and R. Brown. (52) Plantae Javanicae rariores. London,
1838–52.
Benson, Margaret. (08) On the contents of the pollen-chamber of a
specimen of Lagenostoma ovoides. Bot. Gaz. vol. lv. p. 409.
—— (12) Cordaites Felicis, sp. nov., a Cordaitean leaf from the Coal
Measures of England. Ann. Bot. vol. xxvi. p. 202.
—— (14) Sphaerostoma ovale (Conostoma ovale et intermedianum,
Williamson), a Lower Carboniferous ovule from Pettycur, Fifeshire,
Scotland. Trans. R. Soc. Edinburgh, vol. l. pt. i. No. i. p. 1.
Benson, M. and E. J. Welsford. (09) The morphology of the ovule and
female flower of Juglans regia and of a few allied genera. Ann. Bot.
vol. xxiii. p. 623.
Berger, R. (48) De fructibus et seminibus ex formatione lithanthracum.
Diss. Inaug. Vratislaviae.
Bergeron, J. (84) Note sur les strobiles du Walchia piniformis. Bull. soc.
géol. France [3], Tome xii. p. 583.
Berridge, E. M. (11) On some points of resemblance between Gnetalean
and Bennettitean seeds. New Phyt. vol. x. p. 140.
—— (12) The structure of the female strobilus in Gnetum Gnemon. Ann.
Bot. vol. xxvi. p. 987.
Berridge, Emily M. and Elizabeth Sanday. (07) Oogenesis and
embryogeny in Ephedra distachya. New Phyt. vol. vi. p. 127.
Berry, E. W. (03) The Flora of the Matawan Formation. Bull. New York
Bot. Gard. vol. iii. No. 9, p. 45.
—— (05) Additions to the fossil Flora from Cliffwood. Bull. Torrey Bot.
Club, vol. xxxii. p. 43.
—— (06) Contributions to the Mesozoic Flora of the Atlantic Coastal Plain.
I. Ibid. vol. xxxiii. p. 33.
—— (07) Coastal Plain Amber. Torreya, vol. vii. p. 4.
—— (072) Contributions to the Pleistocene Flora of North Carolina. Journ.
Geol. vol. xv. No. 4, p. 338.
—— (08) Some Araucarian remains from the Atlantic Coastal Plain. Bull.
Torrey Bot. Club, vol. xxxv. p. 249.
Bemerkungen über Cryptomeria. Beiheft Bot. Cent. Bd. xxiii. Abt. i. p.
27.
Beissner, L. (91) Handbuch der Nadelholzkunde. Berlin.
Bennett, J. J. and R. Brown. (52) Plantae Javanicae rariores. London,
1838–52.
Benson, Margaret. (08) On the contents of the pollen-chamber of a
specimen of Lagenostoma ovoides. Bot. Gaz. vol. lv. p. 409.
—— (12) Cordaites Felicis, sp. nov., a Cordaitean leaf from the Coal
Measures of England. Ann. Bot. vol. xxvi. p. 202.
—— (14) Sphaerostoma ovale (Conostoma ovale et intermedianum,
Williamson), a Lower Carboniferous ovule from Pettycur, Fifeshire,
Scotland. Trans. R. Soc. Edinburgh, vol. l. pt. i. No. i. p. 1.
Benson, M. and E. J. Welsford. (09) The morphology of the ovule and
female flower of Juglans regia and of a few allied genera. Ann. Bot.
vol. xxiii. p. 623.
Berger, R. (48) De fructibus et seminibus ex formatione lithanthracum.
Diss. Inaug. Vratislaviae.
Bergeron, J. (84) Note sur les strobiles du Walchia piniformis. Bull. soc.
géol. France [3], Tome xii. p. 583.
Berridge, E. M. (11) On some points of resemblance between Gnetalean
and Bennettitean seeds. New Phyt. vol. x. p. 140.
—— (12) The structure of the female strobilus in Gnetum Gnemon. Ann.
Bot. vol. xxvi. p. 987.
Berridge, Emily M. and Elizabeth Sanday. (07) Oogenesis and
embryogeny in Ephedra distachya. New Phyt. vol. vi. p. 127.
Berry, E. W. (03) The Flora of the Matawan Formation. Bull. New York
Bot. Gard. vol. iii. No. 9, p. 45.
—— (05) Additions to the fossil Flora from Cliffwood. Bull. Torrey Bot.
Club, vol. xxxii. p. 43.
—— (06) Contributions to the Mesozoic Flora of the Atlantic Coastal Plain.
I. Ibid. vol. xxxiii. p. 33.
—— (07) Coastal Plain Amber. Torreya, vol. vii. p. 4.
—— (072) Contributions to the Pleistocene Flora of North Carolina. Journ.
Geol. vol. xv. No. 4, p. 338.
—— (08) Some Araucarian remains from the Atlantic Coastal Plain. Bull.
Torrey Bot. Club, vol. xxxv. p. 249.
Page 642
—— (082) A Mid-Cretaceous species of Torreya. Amer. Journ. Sci. vol. xxv.
p. 382.
—— (09) A Miocene Flora from the Virginian Coastal Plain. Journ. Geol.
vol. xvii. p. 19.
—— (092) Pleistocene Swamp deposits in Virginia. Amer. Nat. vol. xliii. p.
432.
—— (10) A revision of the Fossil Plants of the genus Nageiopsis of
Fontaine. Proc. U. S. Nat. Mus. vol. xxxviii. p. 185.
—— (102) The epidermal characters of Frenelopsis ramosissimus. Bot. Gaz.
vol. l. p. 305.
—— (103) Additions to the Pleistocene Flora of New Jersey. Torreya, vol.
x. p. 261.
—— (104) Contributions to the Mesozoic Flora of the Atlantic Coastal
Plain. V. North Carolina. Bull. Torrey Bot. Club, vol. xxxvii. p. 181.
—— (11) The Lower Cretaceous deposits of Maryland. (Berry, Clark, and
Bibbin.) Maryland Geol. Surv.
—— (112) A Lower Cretaceous species of Schizaeaceae from Eastern North
America. Ann. Bot. vol. xxv. p. 193.
—— (113) The Flora of the Raritan Formation. Geol. Surv. New Jersey,
Bull. 3.
—— (114) A Revision of several genera of Gymnospermous plants from the
Potomac group in Maryland and Virginia. Proc. U. S. Nat. Mus. vol.
xl. p. 289.
—— (12) The age of the plant-bearing shales of the Richmond coal-field.
Amer. Journ. Sci. vol. xxxiv. p. 224.
—— (122) Notes on the genus Widdringtonites. Bull. Torr. Bot. Club, vol.
xxxix. p. 341.
—— (123) Contributions to the Mesozoic Flora of the Atlantic Coastal
Plain. VII. Texas. Bull. Torrey Bot. Club, vol. xxxix. p. 387.
—— (124) Pleistocene plants from the Blue Ridge in Virginia. Amer. Journ.
Sci. vol. xxxiv. p. 218.
—— (14) The Upper Cretaceous and Eocene floras of South Carolina and
Georgia. U. S. Geol. Surv. Professional papers, No. 84.
—— (15) The Mississippi River Bluffs at Columbus and Hickman,
Kentucky, and their Fossil Flora. Proc. U. S. Nat. Mus. vol. xlviii. p.
293.
p. 382.
—— (09) A Miocene Flora from the Virginian Coastal Plain. Journ. Geol.
vol. xvii. p. 19.
—— (092) Pleistocene Swamp deposits in Virginia. Amer. Nat. vol. xliii. p.
432.
—— (10) A revision of the Fossil Plants of the genus Nageiopsis of
Fontaine. Proc. U. S. Nat. Mus. vol. xxxviii. p. 185.
—— (102) The epidermal characters of Frenelopsis ramosissimus. Bot. Gaz.
vol. l. p. 305.
—— (103) Additions to the Pleistocene Flora of New Jersey. Torreya, vol.
x. p. 261.
—— (104) Contributions to the Mesozoic Flora of the Atlantic Coastal
Plain. V. North Carolina. Bull. Torrey Bot. Club, vol. xxxvii. p. 181.
—— (11) The Lower Cretaceous deposits of Maryland. (Berry, Clark, and
Bibbin.) Maryland Geol. Surv.
—— (112) A Lower Cretaceous species of Schizaeaceae from Eastern North
America. Ann. Bot. vol. xxv. p. 193.
—— (113) The Flora of the Raritan Formation. Geol. Surv. New Jersey,
Bull. 3.
—— (114) A Revision of several genera of Gymnospermous plants from the
Potomac group in Maryland and Virginia. Proc. U. S. Nat. Mus. vol.
xl. p. 289.
—— (12) The age of the plant-bearing shales of the Richmond coal-field.
Amer. Journ. Sci. vol. xxxiv. p. 224.
—— (122) Notes on the genus Widdringtonites. Bull. Torr. Bot. Club, vol.
xxxix. p. 341.
—— (123) Contributions to the Mesozoic Flora of the Atlantic Coastal
Plain. VII. Texas. Bull. Torrey Bot. Club, vol. xxxix. p. 387.
—— (124) Pleistocene plants from the Blue Ridge in Virginia. Amer. Journ.
Sci. vol. xxxiv. p. 218.
—— (14) The Upper Cretaceous and Eocene floras of South Carolina and
Georgia. U. S. Geol. Surv. Professional papers, No. 84.
—— (15) The Mississippi River Bluffs at Columbus and Hickman,
Kentucky, and their Fossil Flora. Proc. U. S. Nat. Mus. vol. xlviii. p.
293.
Page 643
—— (16) The Geological history of Gymnosperms. The Plant World, vol.
xix. p. 27.
Bertrand, C. E. (74) Anatomie comparée des tiges et des feuilles chez les
Gnétacées et les Conifères. Ann. Sci. nat. [v], vol. xx. p. 5.
—— (83) Note sur le genre Vesquia, Taxinée fossile du Terrain Aachénien
de Tournai. Bull. soc. bot. France [3], Tome v. p. 293.
—— (89) Les Poroxylons végétaux fossiles de l’époque houillière. Ann.
soc. Belg. de Microscopie, Tome xiii. Fasc. i.
—— (98) Remarques sur la structure des grains de pollen de Cordaites.
Assoc. Franç. pour l’avanc. des Sci. Nantes (1898), p. 436.
—— (07) Les caractéristiques du genre Rhabdocarpus d’après les
préparations de la collection B. Renault. Bull. soc. bot. [4], Tome vii, p.
654.
—— (072) Les caractéristiques du genre Diplotesta de Brongniart. Bull. soc.
bot. France [4], tome vii. p. 388.
—— (073) Les caractéristiques du genre Leptocaryon de Brongniart. Ibid. p.
452.
—— (074) Les caractéristiques du genre Taxospermum de Brongniart. Ibid.
p. 213.
—— (075) Remarques sur le Taxospermum angulosum. Compt. rend.
d’assoc. Franç. pour l’avanc. des sci. (Reims, 1907), p. 410.
—— (08) Les caractéristiques du Cycadinocarpus angustodunensis de B.
Renault. Bull. soc. bot. France [4], tome viii. p. 326.
—— (082) Les caractéristiques du genre Cardiocarpus d’après les graines
silicifiées étudiées par Ad. Brongniart et B. Renault. Ibid. p. 391.
—— (083) La spécification des Cardiocarpus de la collection B. Renault.
Ibid. p. 454.
—— (09) Sur le genre Compsotesta de Ad. Brongniart. Ann. Jard. Bot.
Buit. [2], suppl. 3.
—— (11) Le Bourgeon femelle des Cordaites. Nancy.
Bertrand, C. E. et B. Renault. (82) Recherches sur les Poroxylons. Arch.
bot. du Nord de la France, vol. ii. p. 243.
Bertrand, P. (08) Sur les stipes de Clepsydropsis. Compt. Rend., Nov. 16,
1908.
—— (11) Structure des stipes d’Asterochlaena laxa Sterzel. Mém. soc. géol.
Nord, Tome vii. i.
xix. p. 27.
Bertrand, C. E. (74) Anatomie comparée des tiges et des feuilles chez les
Gnétacées et les Conifères. Ann. Sci. nat. [v], vol. xx. p. 5.
—— (83) Note sur le genre Vesquia, Taxinée fossile du Terrain Aachénien
de Tournai. Bull. soc. bot. France [3], Tome v. p. 293.
—— (89) Les Poroxylons végétaux fossiles de l’époque houillière. Ann.
soc. Belg. de Microscopie, Tome xiii. Fasc. i.
—— (98) Remarques sur la structure des grains de pollen de Cordaites.
Assoc. Franç. pour l’avanc. des Sci. Nantes (1898), p. 436.
—— (07) Les caractéristiques du genre Rhabdocarpus d’après les
préparations de la collection B. Renault. Bull. soc. bot. [4], Tome vii, p.
654.
—— (072) Les caractéristiques du genre Diplotesta de Brongniart. Bull. soc.
bot. France [4], tome vii. p. 388.
—— (073) Les caractéristiques du genre Leptocaryon de Brongniart. Ibid. p.
452.
—— (074) Les caractéristiques du genre Taxospermum de Brongniart. Ibid.
p. 213.
—— (075) Remarques sur le Taxospermum angulosum. Compt. rend.
d’assoc. Franç. pour l’avanc. des sci. (Reims, 1907), p. 410.
—— (08) Les caractéristiques du Cycadinocarpus angustodunensis de B.
Renault. Bull. soc. bot. France [4], tome viii. p. 326.
—— (082) Les caractéristiques du genre Cardiocarpus d’après les graines
silicifiées étudiées par Ad. Brongniart et B. Renault. Ibid. p. 391.
—— (083) La spécification des Cardiocarpus de la collection B. Renault.
Ibid. p. 454.
—— (09) Sur le genre Compsotesta de Ad. Brongniart. Ann. Jard. Bot.
Buit. [2], suppl. 3.
—— (11) Le Bourgeon femelle des Cordaites. Nancy.
Bertrand, C. E. et B. Renault. (82) Recherches sur les Poroxylons. Arch.
bot. du Nord de la France, vol. ii. p. 243.
Bertrand, P. (08) Sur les stipes de Clepsydropsis. Compt. Rend., Nov. 16,
1908.
—— (11) Structure des stipes d’Asterochlaena laxa Sterzel. Mém. soc. géol.
Nord, Tome vii. i.
Page 644
—— (13) Les Fructifications de Neuroptéridées recueillies dans le terrain
houiller du Nord de la France. Ann. soc. géol. Nord, Tome xlii. p. 113.
—— (14) État actuel de nos Connaissances sur les Genres ‘Cladoxylon’ et
‘Steloxylon.’ Compt. Rend. de l’assoc. franç. pour l’Avancement des
Sciences (Havre, 1914), p. 446.
Beust, F. (85) Untersuchung über fossile Hölzer aus Grönland. Neue
Denksch. allgem. Schweiz. Ges. gesammt. Naturwiss. Bd. xxix.
Binney, E. W. (66) On Fossil wood in calcareous nodules found in the
upper foot coal near Oldham. Proc. Lit. Phil. Soc. Manchester, vol. v.
p. 113.
Bleicher and Fliche. (92) Contribution à l’étude des Terrains Tertiaires
d’Alsace. Bull. soc. géol. France [3], Tome xx. p. 375.
Bodenbender, W. (96) Beobachtungen über Devon- und Gondwana-
Schichten in der Argentinischen Republik. Zeitsch. Deutsch. geol. Ges.
Bd. xlviii. p. 743.
—— (02) Contribucion al Conocimiento de la Precordillera de San Juan de
Mendoza. Bot. Acad. Nac. Cienc. Cordoba, vol. xvii. p. 203.
Boodle, L. A. (15) Concrescent and solitary Foliage-leaves in Pinus. New
Phyt. vol. xiv. p. 19.
Boodle, L. A. and W. C. Worsdell. (94) On the comparative anatomy of the
Casuarineae, with special reference to the Gnetaceae and Cupuliferae.
Ann. Bot. vol. viii. p. 231.
Boulay. (79) Recherches de paléontologie végétale dans le terrain houiller
du Nord de la France. Ann. soc. scient. Bruxelles, ann. iv. pt. 2, 1880.
—— (87) Notice sur la Flore tertiaire des environs de Privas (Ardiche).
Bull. soc. bot. France, Tome xxxiv. p. 227.
—— (88) Notice sur les Plantes fossiles des grès tertiaires de Saint-Saturnin
(Marne et Loire). Journ. Bot. Ann. 2, p. 921.
Bower, F. O. (81) On the germination and histology of the seedlings of
Welwitschia mirabilis. Quart. Journ. Micr. soc. vol. xxi. pp. 15, 571.
—— (82) The germination and embryogeny of Gnetum Gnemon. Ibid. vol.
xxii. [N.S.], p. 277.
—— (84) On the structure of Rhynchopetalum montanum. Journ. Lin. Soc.
vol. xx. p. 440.
—— (12) Studies in the Phylogeny of the Filicales. II. Lophosira, and its
relation to the Cyatheoideae and other Ferns. Ann. Bot. vol. xxvi. p.
269.
houiller du Nord de la France. Ann. soc. géol. Nord, Tome xlii. p. 113.
—— (14) État actuel de nos Connaissances sur les Genres ‘Cladoxylon’ et
‘Steloxylon.’ Compt. Rend. de l’assoc. franç. pour l’Avancement des
Sciences (Havre, 1914), p. 446.
Beust, F. (85) Untersuchung über fossile Hölzer aus Grönland. Neue
Denksch. allgem. Schweiz. Ges. gesammt. Naturwiss. Bd. xxix.
Binney, E. W. (66) On Fossil wood in calcareous nodules found in the
upper foot coal near Oldham. Proc. Lit. Phil. Soc. Manchester, vol. v.
p. 113.
Bleicher and Fliche. (92) Contribution à l’étude des Terrains Tertiaires
d’Alsace. Bull. soc. géol. France [3], Tome xx. p. 375.
Bodenbender, W. (96) Beobachtungen über Devon- und Gondwana-
Schichten in der Argentinischen Republik. Zeitsch. Deutsch. geol. Ges.
Bd. xlviii. p. 743.
—— (02) Contribucion al Conocimiento de la Precordillera de San Juan de
Mendoza. Bot. Acad. Nac. Cienc. Cordoba, vol. xvii. p. 203.
Boodle, L. A. (15) Concrescent and solitary Foliage-leaves in Pinus. New
Phyt. vol. xiv. p. 19.
Boodle, L. A. and W. C. Worsdell. (94) On the comparative anatomy of the
Casuarineae, with special reference to the Gnetaceae and Cupuliferae.
Ann. Bot. vol. viii. p. 231.
Boulay. (79) Recherches de paléontologie végétale dans le terrain houiller
du Nord de la France. Ann. soc. scient. Bruxelles, ann. iv. pt. 2, 1880.
—— (87) Notice sur la Flore tertiaire des environs de Privas (Ardiche).
Bull. soc. bot. France, Tome xxxiv. p. 227.
—— (88) Notice sur les Plantes fossiles des grès tertiaires de Saint-Saturnin
(Marne et Loire). Journ. Bot. Ann. 2, p. 921.
Bower, F. O. (81) On the germination and histology of the seedlings of
Welwitschia mirabilis. Quart. Journ. Micr. soc. vol. xxi. pp. 15, 571.
—— (82) The germination and embryogeny of Gnetum Gnemon. Ibid. vol.
xxii. [N.S.], p. 277.
—— (84) On the structure of Rhynchopetalum montanum. Journ. Lin. Soc.
vol. xx. p. 440.
—— (12) Studies in the Phylogeny of the Filicales. II. Lophosira, and its
relation to the Cyatheoideae and other Ferns. Ann. Bot. vol. xxvi. p.
269.
Page 645
Bowerbank, J. S. (40) History of the Fossil fruits and seeds of the London
Clay. London.
Braun, A. (75) Die Frage nach der Gymnospermie der Cycadeen.
Monatsber. K. Preuss. Akad. Wiss. Berlin, p. 289.
—— (752) Die Diagnosen dreier im Jahre 1873 von G. Wallis in Neu
Granada entdeckter Cycadeen. Ibid. p. 376.
Braun, C. F. W. (43) Beiträge zur Petrefactenkunde Bayreuth (Graf zu
Münster), Heft vi. Bayreuth.
—— (47) Die Fossile Gewächse aus den Grenzschichten zwischen dem
Lias und Keuper des neu aufgefundenen Pflanzenlagers in dem
Steinbrüche von Veitlahm bei Culmbach. Flora, p. 81.
—— (49) Beiträge zur Urgeschichte der Pflanzen. VI. Weltrichia eine neue
Gattung fossiler Rhizantheen. Progr. iii. Jahresber. K. Kreis-
Landwirthsch. und Gewerbschule zu Bayreuth.
Brauns, D. (66) Der Sandstein bei Seinstedt unweit des Fallsteins und die
in ihm vorkommenden Pflanzenreste. Paleont. Bd. ix. p. 47.
Brenchley, Winifred E. (13) On Branching specimens of Lyginodendron
Oldhamium Will. Journ. Linn. Soc. vol. xli. p. 349.
Bristow, H. W. (62) The Geology of the Isle of Wight. Mem. Geol. Surv.
Great Britain.
Brongniart, A. (25) Observations sur les végétaux fossiles renfermés dans
les grès de Hoer en Scanie. Ann. Sci. nat. vol. iv. p. 200.
—— (28) Essai d’une Flore du grès bigarré. Ann. Sci. nat. vol. v. p. 435.
—— (33) Notice sur une Conifère fossile du terrain d’eau douce de l’île
d’Iliodroma. Ann. Sci. nat. tome xxx. p. 175.
—— (74) Études sur les graines fossiles trouvées à l’état silicifié dans le
terrain Houiller de Saint Étienne. Ann. Sci. nat. tome xx. [5], p. 234.
—— (81) Recherches sur les graines fossiles silicifiées. Paris.
Bronn, H. G. (58) Beiträge zur triassischen Schiefer von Raibl. Neues
Jahrb. Min. p. 129.
Brooks, F. T. and A. Sharples. (14) Pink disease. Bull. No. 21, Depart.
Agric. Fed. Malay States.
Brooks, F. T. and W. Stiles. (10) The structure of Podocarpus spinulosus
(Smith) R. Br. Ann. Bot. vol. xxiv. p. 305.
Buchman, J. (45) Outline of the Geology of the neighbourhood of
Cheltenham (in collaboration with R. I. Murchison and H. E.
Strickland). London.
Clay. London.
Braun, A. (75) Die Frage nach der Gymnospermie der Cycadeen.
Monatsber. K. Preuss. Akad. Wiss. Berlin, p. 289.
—— (752) Die Diagnosen dreier im Jahre 1873 von G. Wallis in Neu
Granada entdeckter Cycadeen. Ibid. p. 376.
Braun, C. F. W. (43) Beiträge zur Petrefactenkunde Bayreuth (Graf zu
Münster), Heft vi. Bayreuth.
—— (47) Die Fossile Gewächse aus den Grenzschichten zwischen dem
Lias und Keuper des neu aufgefundenen Pflanzenlagers in dem
Steinbrüche von Veitlahm bei Culmbach. Flora, p. 81.
—— (49) Beiträge zur Urgeschichte der Pflanzen. VI. Weltrichia eine neue
Gattung fossiler Rhizantheen. Progr. iii. Jahresber. K. Kreis-
Landwirthsch. und Gewerbschule zu Bayreuth.
Brauns, D. (66) Der Sandstein bei Seinstedt unweit des Fallsteins und die
in ihm vorkommenden Pflanzenreste. Paleont. Bd. ix. p. 47.
Brenchley, Winifred E. (13) On Branching specimens of Lyginodendron
Oldhamium Will. Journ. Linn. Soc. vol. xli. p. 349.
Bristow, H. W. (62) The Geology of the Isle of Wight. Mem. Geol. Surv.
Great Britain.
Brongniart, A. (25) Observations sur les végétaux fossiles renfermés dans
les grès de Hoer en Scanie. Ann. Sci. nat. vol. iv. p. 200.
—— (28) Essai d’une Flore du grès bigarré. Ann. Sci. nat. vol. v. p. 435.
—— (33) Notice sur une Conifère fossile du terrain d’eau douce de l’île
d’Iliodroma. Ann. Sci. nat. tome xxx. p. 175.
—— (74) Études sur les graines fossiles trouvées à l’état silicifié dans le
terrain Houiller de Saint Étienne. Ann. Sci. nat. tome xx. [5], p. 234.
—— (81) Recherches sur les graines fossiles silicifiées. Paris.
Bronn, H. G. (58) Beiträge zur triassischen Schiefer von Raibl. Neues
Jahrb. Min. p. 129.
Brooks, F. T. and A. Sharples. (14) Pink disease. Bull. No. 21, Depart.
Agric. Fed. Malay States.
Brooks, F. T. and W. Stiles. (10) The structure of Podocarpus spinulosus
(Smith) R. Br. Ann. Bot. vol. xxiv. p. 305.
Buchman, J. (45) Outline of the Geology of the neighbourhood of
Cheltenham (in collaboration with R. I. Murchison and H. E.
Strickland). London.
Page 646
Buckland, W. (28) On the Cycadeoideae, a Family of Fossil Plants found in
the Oolite quarries of the Isle of Portland. Trans. Geol. Soc. [2], vol. ii.
p. 395.
—— (37) Geology and Mineralogy considered with reference to Natural
Theology. London.
Burckhardt, C. (11) Bemerkungen zu einigen Arbeiten von W. Gothan und
A. G. Nathorst. Cent. Min. Geol.; Paleont. p. 442.
Burgestein, A. (06) Zur Holzanatomie der Tanne, Fichte und Lärche. Ber.
deutsch. Bot. Ges. Bd. xxiv. Heft vi. p. 295.
—— (08) Vergleichende Anatomie des Holzes der Koniferen. Wiesner-
Festschrift, Wien.
Burlingame, L. (08) The staminate cone and male gametophyte of
Podocarpus. Bot. Gaz. vol. xlvi. p. 161.
—— (13) The Morphology of Araucaria brasiliensis. Bot. Gaz. vol. lv. p.
97.
—— (15) The Morphology of Araucaria brasiliensis. Ibid. vol. lix. p. 1.
—— (152) The Origin and Relationships of the Araucarians. Ibid. vol. lx. p.
1.
Butterworth, J. (97) Some further investigations of Fossil seeds of the
genus Lagenostoma (Williamson) from the Lower Coal Measures,
Oldham. Mem. Proc. Manchester Lit. and Phil. Soc. vol. xli. ix. p. 1.
Caldwell, O. W. (07) Microcycas calocoma. Bot. Gaz. vol. xliv. p. 118.
Caldwell, O. W. and C. F. Baker. (07) The identity of Microcycas
calocoma. Ibid. vol. xliii. p. 130.
Cambier, R. et A. Renier. (10) Psygmophyllum Delvali n. sp. du Terrain
houiller de Charleroi. Ann. soc. géol. Belg. Tome ii. p. 23. (Mém. in
4to.)
Capellini, G. and Conte E. Solms-Laubach. (92) I Tronchi di Bennettitee
dei Musei Italiani. Mem. Reale Acad. Sci. Istit. Bologna [5], tom. ii. p.
161.
Carano, E. (04) Contribuzione alla conoscenza della Morfologia e dello
sviluppo del fascio vascolare delle foglie delle Cicadacee. Ann. di Bot.
vol. i. p. 109 (Rome).
Carpentier, A. (11) Sur quelques fructifications et inflorescences du
Westphalien du Nord de la France. Rev. Gén. Bot. tome xxiii. p. 1.
—— (13) Contribution à l’étude du Carbonifère du Nord de la France.
Mém. soc. géol. du Nord, tome vii. ii. p. 1.
the Oolite quarries of the Isle of Portland. Trans. Geol. Soc. [2], vol. ii.
p. 395.
—— (37) Geology and Mineralogy considered with reference to Natural
Theology. London.
Burckhardt, C. (11) Bemerkungen zu einigen Arbeiten von W. Gothan und
A. G. Nathorst. Cent. Min. Geol.; Paleont. p. 442.
Burgestein, A. (06) Zur Holzanatomie der Tanne, Fichte und Lärche. Ber.
deutsch. Bot. Ges. Bd. xxiv. Heft vi. p. 295.
—— (08) Vergleichende Anatomie des Holzes der Koniferen. Wiesner-
Festschrift, Wien.
Burlingame, L. (08) The staminate cone and male gametophyte of
Podocarpus. Bot. Gaz. vol. xlvi. p. 161.
—— (13) The Morphology of Araucaria brasiliensis. Bot. Gaz. vol. lv. p.
97.
—— (15) The Morphology of Araucaria brasiliensis. Ibid. vol. lix. p. 1.
—— (152) The Origin and Relationships of the Araucarians. Ibid. vol. lx. p.
1.
Butterworth, J. (97) Some further investigations of Fossil seeds of the
genus Lagenostoma (Williamson) from the Lower Coal Measures,
Oldham. Mem. Proc. Manchester Lit. and Phil. Soc. vol. xli. ix. p. 1.
Caldwell, O. W. (07) Microcycas calocoma. Bot. Gaz. vol. xliv. p. 118.
Caldwell, O. W. and C. F. Baker. (07) The identity of Microcycas
calocoma. Ibid. vol. xliii. p. 130.
Cambier, R. et A. Renier. (10) Psygmophyllum Delvali n. sp. du Terrain
houiller de Charleroi. Ann. soc. géol. Belg. Tome ii. p. 23. (Mém. in
4to.)
Capellini, G. and Conte E. Solms-Laubach. (92) I Tronchi di Bennettitee
dei Musei Italiani. Mem. Reale Acad. Sci. Istit. Bologna [5], tom. ii. p.
161.
Carano, E. (04) Contribuzione alla conoscenza della Morfologia e dello
sviluppo del fascio vascolare delle foglie delle Cicadacee. Ann. di Bot.
vol. i. p. 109 (Rome).
Carpentier, A. (11) Sur quelques fructifications et inflorescences du
Westphalien du Nord de la France. Rev. Gén. Bot. tome xxiii. p. 1.
—— (13) Contribution à l’étude du Carbonifère du Nord de la France.
Mém. soc. géol. du Nord, tome vii. ii. p. 1.
Page 647
Carruthers, W. (66) On Araucarian cones from the Secondary beds of
Britain. Geol. Mag. vol. iii. p. 249.
—— (662) On some fossil Coniferous fruits. Ibid. vol. iii. p. 534.
—— (67) On Cycadeoidea Yatesii sp. nov. a fossil Cycadean stem from the
Potton sands, Bedfordshire. Ibid. vol. iv. p. 199.
—— (672) On Gymnospermous Fruits from the Secondary rocks of Britain.
Journ. Bot. vol. v. p. 1.
—— (673) On some Cycadean Fruits from the Secondary rocks of Britain.
Geol. Mag. vol. iv. p. 101.
—— (68) British Fossil Pandanaceae. Ibid. vol. v. p. 153.
—— (69) On Beania, a new genus of Cycadean Fruit from the Yorkshire
Oolite. Ibid. vol. vi. p. 1.
—— (692) On some undescribed Coniferous fruits from the Secondary
rocks of Britain. Ibid. vol. vi. p. 1.
—— (70) On Fossil Cycadean stems from the Secondary rocks of Britain.
Trans. Linn. Soc. vol. xxvi. p. 675.
—— (71) On two undescribed Coniferous fruits from the Secondary rocks
of Britain. Geol. Mag. vol. viii. p. 1.
—— (77) Description of a new species of Araucarites from the Coralline
Oolite of Malton. Quart. Journ. Geol. Soc. vol. xxxiii. p. 402.
—— (93) On Cycas Taiwaniana, sp. nov. and C. Seemanni R. Br. Journ.
Bot. vol. xxxi. p. 1.
Carter, M. Geraldine. (11) A Reconsideration of the origin of Transfusion-
tissue. Ann. Bot. vol. xxv. p. 975.
Caspary, R. and R. Triebel. (89) Einige fossile Hölzer Preussens. K.
Preuss. Geol. Landesanstalt, Bd. ix. Heft iii. p. 113.
Čelakovský, L. (82) Zur Kritik der Ansichten von den Fruchtschuppe der
Abietineen. Abh. K. böhm. Ges. Wiss. Prag [vi], Bd. ii.
Chamberlain, C. J. (06) The ovule and female gametophyte of Dioon. Bot.
Gaz. vol. xlii. p. 321.
—— (09) Dioon spinulosum. Ibid. vol. xlviii. p. 401.
—— (10) See Coulter and Chamberlain.
—— (102) Fertilization and embryogeny in Dioon edule. Bot. Gaz. vol. l. p.
415.
—— (11) The adult Cycad Trunk. Ibid. vol. lii. p. 81.
—— (12) Morphology of Ceratozamia. Ibid. vol. liii. p. 1.
Britain. Geol. Mag. vol. iii. p. 249.
—— (662) On some fossil Coniferous fruits. Ibid. vol. iii. p. 534.
—— (67) On Cycadeoidea Yatesii sp. nov. a fossil Cycadean stem from the
Potton sands, Bedfordshire. Ibid. vol. iv. p. 199.
—— (672) On Gymnospermous Fruits from the Secondary rocks of Britain.
Journ. Bot. vol. v. p. 1.
—— (673) On some Cycadean Fruits from the Secondary rocks of Britain.
Geol. Mag. vol. iv. p. 101.
—— (68) British Fossil Pandanaceae. Ibid. vol. v. p. 153.
—— (69) On Beania, a new genus of Cycadean Fruit from the Yorkshire
Oolite. Ibid. vol. vi. p. 1.
—— (692) On some undescribed Coniferous fruits from the Secondary
rocks of Britain. Ibid. vol. vi. p. 1.
—— (70) On Fossil Cycadean stems from the Secondary rocks of Britain.
Trans. Linn. Soc. vol. xxvi. p. 675.
—— (71) On two undescribed Coniferous fruits from the Secondary rocks
of Britain. Geol. Mag. vol. viii. p. 1.
—— (77) Description of a new species of Araucarites from the Coralline
Oolite of Malton. Quart. Journ. Geol. Soc. vol. xxxiii. p. 402.
—— (93) On Cycas Taiwaniana, sp. nov. and C. Seemanni R. Br. Journ.
Bot. vol. xxxi. p. 1.
Carter, M. Geraldine. (11) A Reconsideration of the origin of Transfusion-
tissue. Ann. Bot. vol. xxv. p. 975.
Caspary, R. and R. Triebel. (89) Einige fossile Hölzer Preussens. K.
Preuss. Geol. Landesanstalt, Bd. ix. Heft iii. p. 113.
Čelakovský, L. (82) Zur Kritik der Ansichten von den Fruchtschuppe der
Abietineen. Abh. K. böhm. Ges. Wiss. Prag [vi], Bd. ii.
Chamberlain, C. J. (06) The ovule and female gametophyte of Dioon. Bot.
Gaz. vol. xlii. p. 321.
—— (09) Dioon spinulosum. Ibid. vol. xlviii. p. 401.
—— (10) See Coulter and Chamberlain.
—— (102) Fertilization and embryogeny in Dioon edule. Bot. Gaz. vol. l. p.
415.
—— (11) The adult Cycad Trunk. Ibid. vol. lii. p. 81.
—— (12) Morphology of Ceratozamia. Ibid. vol. liii. p. 1.
Page 648
—— (122) A round-the-world Botanical Excursion. Pop. Sci. Monthly, vol.
lxxxi. p. 417.
—— (123) Two species of Bowenia. Bot. Gaz. vol. liv. p. 419.
—— (13) Macrozamia Moorei, a connecting link between living and fossil
Cycads. Bot. Gaz. vol. lv. p. 141.
Chapman, F. (09) Jurassic Plant-remains from Gippsland, Pt. ii. Rec. Geol.
Surv. Victoria, vol. iii. pt. i. p. 103.
Chrysler, M. A. (15) The Medullary rays of Cedrus. Bot. Gaz. vol. lix. p.
387.
Church, A. H. (14) On the Floral Morphology of Welwitschia mirabilis
(Hooker). Phil. Trans. R. Soc. vol. 205, p. 115.
Cockerell, T. D. A. (06) The Fossil Flora and Fauna of the Florissant
(Colorado) shales. Univ. Colorado Series, vol. iii. No. 3.
—— (08) Description of Tertiary Plants. II. Amer. Journ. Sci. vol. xxvi [4], p.
537.
—— (082). The Fossil Flora of Florissant, Colorado. Bull. Amer. Mus. Nat.
Hist. vol. xxiv. p. 71.
—— (083) Florissant; a Miocene Pompeii. Pop. Sci. Monthly (Aug. 1908, p.
112).
Coemans, E. (66) Description de la flore fossile du premier étage du terrain
Crétacé du Hainaut. Mém. Acad. R. Belg., tome xxxvi.
Coker, W. C. (03) On the gametophyte and embryo of Taxodium. Bot. Gaz.
vol. xxxvi. p. 1.
—— (09) Vitality of Pine seeds and the delayed opening of cones. Amer.
Nat. vol. xliii. p. 677.
Compter, G. (94) Die fossile Flora des untern Keupers von Ostthüringen.
Zeitsch. für Naturwiss. Leipzig, Bd. lxvii. p. 205.
—— (03) Cycadeenfrüchte aus der Lettenkohle von Apolda. Zeitsch. für
Naturwiss. Stuttgart, Bd. lxxv. p. 171.
Compton, R. H. (08) See South and Compton.
Cowentz, H. (78) Ueber ein tertiares Vorkommen Cypressenartiger Hölzer
bei Calistoga in Californien. Neues Jahrb. Min. p. 800.
—— (82) Fossile Hölzer aus der Sammlung der König. geol. Landesanstalt
zu Berlin. Jahrb. K. preuss. geol. Land. Bergakad. Berlin für das Jahr
1881, p. 144.
—— (85) Sobre algunos arboles fosiles del Rio Negro. Bol. Acad. Nac.
Cienc. Cordoba, tom. vii. p. 575.
lxxxi. p. 417.
—— (123) Two species of Bowenia. Bot. Gaz. vol. liv. p. 419.
—— (13) Macrozamia Moorei, a connecting link between living and fossil
Cycads. Bot. Gaz. vol. lv. p. 141.
Chapman, F. (09) Jurassic Plant-remains from Gippsland, Pt. ii. Rec. Geol.
Surv. Victoria, vol. iii. pt. i. p. 103.
Chrysler, M. A. (15) The Medullary rays of Cedrus. Bot. Gaz. vol. lix. p.
387.
Church, A. H. (14) On the Floral Morphology of Welwitschia mirabilis
(Hooker). Phil. Trans. R. Soc. vol. 205, p. 115.
Cockerell, T. D. A. (06) The Fossil Flora and Fauna of the Florissant
(Colorado) shales. Univ. Colorado Series, vol. iii. No. 3.
—— (08) Description of Tertiary Plants. II. Amer. Journ. Sci. vol. xxvi [4], p.
537.
—— (082). The Fossil Flora of Florissant, Colorado. Bull. Amer. Mus. Nat.
Hist. vol. xxiv. p. 71.
—— (083) Florissant; a Miocene Pompeii. Pop. Sci. Monthly (Aug. 1908, p.
112).
Coemans, E. (66) Description de la flore fossile du premier étage du terrain
Crétacé du Hainaut. Mém. Acad. R. Belg., tome xxxvi.
Coker, W. C. (03) On the gametophyte and embryo of Taxodium. Bot. Gaz.
vol. xxxvi. p. 1.
—— (09) Vitality of Pine seeds and the delayed opening of cones. Amer.
Nat. vol. xliii. p. 677.
Compter, G. (94) Die fossile Flora des untern Keupers von Ostthüringen.
Zeitsch. für Naturwiss. Leipzig, Bd. lxvii. p. 205.
—— (03) Cycadeenfrüchte aus der Lettenkohle von Apolda. Zeitsch. für
Naturwiss. Stuttgart, Bd. lxxv. p. 171.
Compton, R. H. (08) See South and Compton.
Cowentz, H. (78) Ueber ein tertiares Vorkommen Cypressenartiger Hölzer
bei Calistoga in Californien. Neues Jahrb. Min. p. 800.
—— (82) Fossile Hölzer aus der Sammlung der König. geol. Landesanstalt
zu Berlin. Jahrb. K. preuss. geol. Land. Bergakad. Berlin für das Jahr
1881, p. 144.
—— (85) Sobre algunos arboles fosiles del Rio Negro. Bol. Acad. Nac.
Cienc. Cordoba, tom. vii. p. 575.
Page 649
—— (86) Die Angiospermen des Bernsteins. Danzig.
—— (89) Ueber Thyllen und Thyllen-ähnliche Bildungen, vornehmlich im
Hölze der Bernsteinbäume. Ber. Deutsch. Bot. Ges. Bd. vii. p. (34).
—— (92) Untersuchungen über fossile Hölzer Schwedens. K. Svensk.
Vetenskapsakad. Hand. Bd. xxiv. No. 13.
—— (01) The past history of the Yew in Great Britain and Ireland. Rep.
71st Meeting Brit. Assoc. (Glasgow), p. 839.
Coulter, J. M. and C. J. Chamberlain. (03) The Embryogeny of Zamia.
Bot. Gaz. vol. xxxv. p. 184.
—— (10) Morphology of Gymnosperms. Chicago.
Cramer, C. (68) Fossile Hölzer der Arctischen Zone. Heer’s Foss. Flor.
Arct. vol. i. p. 167.
Crié, L. (89) Beiträge zur Kenntniss der fossilen Flora einiger Inseln des
Südpacifischen und Indischen Oceans. Pal. Abhand. (Dames and
Kayser) (N.F.), Bd. i. Heft ii.
Daguillon, A. (90) Recherches morphologiques sur les feuilles des
Conifères. Rev. Gén. Bot. tome 11, p. 154.
Dawson, J. W. (46) Notices of some Fossils found in the Coal Formation of
Nova Scotia. Quart. Journ. Geol. Soc. vol. ii. p. 132.
—— (62) On the Flora of the Devonian period in North-eastern America.
Ibid. vol. xviii. p. 296.
—— (63) Further Observations on the Devonian Plants of Maine, Gaspé,
and New York. Ibid. vol. xix. p. 458.
—— (632) Synopsis of the Flora of the Carboniferous Period in Nova
Scotia. The Canadian Nat. and Geologist, vol. viii. p. 431.
—— (81) Notes on New Erian (Devonian) plants. Quart. Journ. Geol. Soc.
vol. xxxvii. p. 299.
—— (85) On the Mesozoic Floras of the Rocky Mountains Region of
Canada. Trans. R. Soc. Canada, sect. iv. p. 1.
—— (90) On new plants from the Erian and Carboniferous, and on the
characters and affinities of Palaeozoic Gymnosperms. Canadian Rec.
Sci. vol. iv. p. 1.
—— (93) On new species of Cretaceous plants from Vancouver Island.
Trans. R. Soc. Canada, sect. iv. p. 53.
Dawson, Sir J. W. and D. P. Penhallow. (91) Note on the specimens of
Fossil wood from the Erian (Devonian) of New York and Kentucky.
The Canadian Rec. Sci. vol. iv. p. 242.
—— (89) Ueber Thyllen und Thyllen-ähnliche Bildungen, vornehmlich im
Hölze der Bernsteinbäume. Ber. Deutsch. Bot. Ges. Bd. vii. p. (34).
—— (92) Untersuchungen über fossile Hölzer Schwedens. K. Svensk.
Vetenskapsakad. Hand. Bd. xxiv. No. 13.
—— (01) The past history of the Yew in Great Britain and Ireland. Rep.
71st Meeting Brit. Assoc. (Glasgow), p. 839.
Coulter, J. M. and C. J. Chamberlain. (03) The Embryogeny of Zamia.
Bot. Gaz. vol. xxxv. p. 184.
—— (10) Morphology of Gymnosperms. Chicago.
Cramer, C. (68) Fossile Hölzer der Arctischen Zone. Heer’s Foss. Flor.
Arct. vol. i. p. 167.
Crié, L. (89) Beiträge zur Kenntniss der fossilen Flora einiger Inseln des
Südpacifischen und Indischen Oceans. Pal. Abhand. (Dames and
Kayser) (N.F.), Bd. i. Heft ii.
Daguillon, A. (90) Recherches morphologiques sur les feuilles des
Conifères. Rev. Gén. Bot. tome 11, p. 154.
Dawson, J. W. (46) Notices of some Fossils found in the Coal Formation of
Nova Scotia. Quart. Journ. Geol. Soc. vol. ii. p. 132.
—— (62) On the Flora of the Devonian period in North-eastern America.
Ibid. vol. xviii. p. 296.
—— (63) Further Observations on the Devonian Plants of Maine, Gaspé,
and New York. Ibid. vol. xix. p. 458.
—— (632) Synopsis of the Flora of the Carboniferous Period in Nova
Scotia. The Canadian Nat. and Geologist, vol. viii. p. 431.
—— (81) Notes on New Erian (Devonian) plants. Quart. Journ. Geol. Soc.
vol. xxxvii. p. 299.
—— (85) On the Mesozoic Floras of the Rocky Mountains Region of
Canada. Trans. R. Soc. Canada, sect. iv. p. 1.
—— (90) On new plants from the Erian and Carboniferous, and on the
characters and affinities of Palaeozoic Gymnosperms. Canadian Rec.
Sci. vol. iv. p. 1.
—— (93) On new species of Cretaceous plants from Vancouver Island.
Trans. R. Soc. Canada, sect. iv. p. 53.
Dawson, Sir J. W. and D. P. Penhallow. (91) Note on the specimens of
Fossil wood from the Erian (Devonian) of New York and Kentucky.
The Canadian Rec. Sci. vol. iv. p. 242.
Page 650
Depape, G. (13) Sur la présence du Ginkgo biloba L. dans le Pliocène
inférieur de Saint-Marcel-d’Ardèche. Compt. Rend. vol. 157, p. 957.
Depape, G. and A. Carpentier. (13) Présence des genus Gnetopsis B. Ren.
and R. Zeill. et Urnatopteris Kidst. dans le Westphalien du Nord de la
France. Ann. soc. géol. du Nord, tome xlii. p. 294.
—— (15) Sur quelques graines et fructifications du Westphalien du Nord de
la France. Rev. Gén. Bot. vol. xxvii. p. 321.
Dorety, Helen A. (08) The embryo of Ceratozamia, a physiological study.
Bot. Gaz. vol. xlv. p. 412.
—— (082) The seedling of Ceratozamia. Ibid. vol. xlvi. p. 205.
—— (09) The extrafascicular cambium of Ceratozamia. Ibid. vol. xlvii. p.
149.
—— (092) Vascular anatomy of the seedling of Microcycas Calocoma. Ibid.
p. 139.
Dorrien-Smith, A. A. (11) A Botanizing expedition to West Australia.
Journ. R. Hort. Soc. vol. xxxvi. p. 285.
Douvillé, H. et R. Zeiller. (08) Sur le terrain houiller du Sud Oranais.
Compt. Rend. tome cxlvi. p. 732.
Drude, O. (90) Handbuch der Pflanzengeographie. Stuttgart.
Dümmer, R. (12) Podocarpus formosensis. Gard. Chron. Oct. 19, p. 295.
Dun, W. S. (10) Notes on some Fossil plants from the roof of the coal seam
in the Sydney Harbour Colliery. Journ. Proc. R. Soc. New South Wales,
vol. xliv. p. 615.
Duns, J. (72) On Cardiocarpon. Proc. R. Soc. Edinburgh, p. 692.
Dušánek, F. (13) Spaltöffnungen der Cycadaceen. (Abstract in the Bot.
Cent. Bd. cxxv. p. 340.)
Dusén, P. (99) Über die Tertiäre Flora der Magellans-Länder. Wiss. Ergeb.
Schwed. Exped. nach den Magellansländern unter Leitung von O.
Nordenskjöld, Bd. i. No. iv. p. 87.
—— (08) Über die Tertiäre Flora der Seymour-Insel. Wiss. Ergeb. Schwed.
Südpolar-Exped. 1901–03, Bd. iii. Lief. iii. p. 1.
Duthie, Augusta V. (12) Anatomy of Gnetum africanum. Ann. Bot. vol.
xxvi. p. 593.
Eames, A. J. (13) The Morphology of Agathis australis. Ann. Bot. vol.
xxvii. p. 1.
Eberdt, O. (94) Die Braunkohlen Ablagerungen in der Gegend von
Senftenberg. Jahrb. K. Preuss. Geol. Land. Bergakad. Berlin, Bd. xiv.
inférieur de Saint-Marcel-d’Ardèche. Compt. Rend. vol. 157, p. 957.
Depape, G. and A. Carpentier. (13) Présence des genus Gnetopsis B. Ren.
and R. Zeill. et Urnatopteris Kidst. dans le Westphalien du Nord de la
France. Ann. soc. géol. du Nord, tome xlii. p. 294.
—— (15) Sur quelques graines et fructifications du Westphalien du Nord de
la France. Rev. Gén. Bot. vol. xxvii. p. 321.
Dorety, Helen A. (08) The embryo of Ceratozamia, a physiological study.
Bot. Gaz. vol. xlv. p. 412.
—— (082) The seedling of Ceratozamia. Ibid. vol. xlvi. p. 205.
—— (09) The extrafascicular cambium of Ceratozamia. Ibid. vol. xlvii. p.
149.
—— (092) Vascular anatomy of the seedling of Microcycas Calocoma. Ibid.
p. 139.
Dorrien-Smith, A. A. (11) A Botanizing expedition to West Australia.
Journ. R. Hort. Soc. vol. xxxvi. p. 285.
Douvillé, H. et R. Zeiller. (08) Sur le terrain houiller du Sud Oranais.
Compt. Rend. tome cxlvi. p. 732.
Drude, O. (90) Handbuch der Pflanzengeographie. Stuttgart.
Dümmer, R. (12) Podocarpus formosensis. Gard. Chron. Oct. 19, p. 295.
Dun, W. S. (10) Notes on some Fossil plants from the roof of the coal seam
in the Sydney Harbour Colliery. Journ. Proc. R. Soc. New South Wales,
vol. xliv. p. 615.
Duns, J. (72) On Cardiocarpon. Proc. R. Soc. Edinburgh, p. 692.
Dušánek, F. (13) Spaltöffnungen der Cycadaceen. (Abstract in the Bot.
Cent. Bd. cxxv. p. 340.)
Dusén, P. (99) Über die Tertiäre Flora der Magellans-Länder. Wiss. Ergeb.
Schwed. Exped. nach den Magellansländern unter Leitung von O.
Nordenskjöld, Bd. i. No. iv. p. 87.
—— (08) Über die Tertiäre Flora der Seymour-Insel. Wiss. Ergeb. Schwed.
Südpolar-Exped. 1901–03, Bd. iii. Lief. iii. p. 1.
Duthie, Augusta V. (12) Anatomy of Gnetum africanum. Ann. Bot. vol.
xxvi. p. 593.
Eames, A. J. (13) The Morphology of Agathis australis. Ann. Bot. vol.
xxvii. p. 1.
Eberdt, O. (94) Die Braunkohlen Ablagerungen in der Gegend von
Senftenberg. Jahrb. K. Preuss. Geol. Land. Bergakad. Berlin, Bd. xiv.
Page 651
p. 212.
Eichler, A. W. (81) Über die weiblichen Blüthen der Coniferen. Monatsber.
K. Akad. Wiss. Berlin, p. 1020.
—— (82) Über Bildungsabweichungen bei Fichtenzapfen. Sitzber. K. Akad.
Wiss. Berlin, p. 40.
—— (89) Gymnospermae. Engler and Prantl; Die Natürlichen
Pflanzenfamilien, Teil ii.
Eichwald, E. (53–68) Lethaea rossica. Stuttgart.
Elkins, Marion G. and G. R. Wieland. (14) Cordaitean wood from the
Indiana Black Shale. Amer. Journ. Sci. vol. xxxviii. p. 65.
Elwes, H. J. (12) The Flora of Formosa. Gard. Chron. July 13, 1912, p. 25.
Elwes, H. J. and A. Henry. (60) The trees of Great Britain and Ireland, vol.
i. Edinburgh.
Endlicher, S. (40) Genera plantarum secundum ordines naturales disposita.
Vindobonae, 1836–40.
—— (47) Synopsis Coniferarum. Sangalli.
Engelhardt, H. (85) Die Tertiärflora des Jesuitengrabens bei Kundratitz in
Nordböhmen. Nov. Act. K. Leop.-Car. Deutsch. Akad. Naturforsch. Bd.
xlviii. No. 3, p. 299.
—— (91) Über Tertiärpflanzen von Chile. Abh. Senckenberg. naturforsch.
Ges. p. 629.
—— (12) Weiterer Beitrag zur Kenntniss der fossilen Tertiärflora Bosniens.
Wiss. Mitt. aus Bosnien und der Herzegowina, Bd. xii. p. 593.
Engelhardt, H. and F. Kinkelin. (08) Oberpliocene Flora und Fauna des
Unter-Maintales. Abh. Senck. Naturforsch. Ges. Bd. xxix. Heft iii. p.
151.
Engler, A. (89) Engler and Prantl; Die Natürlichen Pflanzenfamilien, Teil ii.
Abt. i.
—— (95) Die Pflanzenwelt Öst Afrikas, etc. Th. C. Berlin.
—— (97) Engler and Prantl; Die Natürlichen Pflanzenfamilien. Nachtrag
zu Teilen ii–iv.
Essner, B. (86) Ueber den diagnostischen Werth der Anzahl und Höhe der
Markstrahlen bei den Coniferen. Abh. naturforsch. Ges. Halle, Bd. xvi.
p. 1.
Etheridge, R. (93) On the occurrence of a plant allied to Schizoneura in the
Hawkesbury Sandstone. Rec. Geol. Surv. New South Wales, vol. iii. pt.
iii, p. 74.
Eichler, A. W. (81) Über die weiblichen Blüthen der Coniferen. Monatsber.
K. Akad. Wiss. Berlin, p. 1020.
—— (82) Über Bildungsabweichungen bei Fichtenzapfen. Sitzber. K. Akad.
Wiss. Berlin, p. 40.
—— (89) Gymnospermae. Engler and Prantl; Die Natürlichen
Pflanzenfamilien, Teil ii.
Eichwald, E. (53–68) Lethaea rossica. Stuttgart.
Elkins, Marion G. and G. R. Wieland. (14) Cordaitean wood from the
Indiana Black Shale. Amer. Journ. Sci. vol. xxxviii. p. 65.
Elwes, H. J. (12) The Flora of Formosa. Gard. Chron. July 13, 1912, p. 25.
Elwes, H. J. and A. Henry. (60) The trees of Great Britain and Ireland, vol.
i. Edinburgh.
Endlicher, S. (40) Genera plantarum secundum ordines naturales disposita.
Vindobonae, 1836–40.
—— (47) Synopsis Coniferarum. Sangalli.
Engelhardt, H. (85) Die Tertiärflora des Jesuitengrabens bei Kundratitz in
Nordböhmen. Nov. Act. K. Leop.-Car. Deutsch. Akad. Naturforsch. Bd.
xlviii. No. 3, p. 299.
—— (91) Über Tertiärpflanzen von Chile. Abh. Senckenberg. naturforsch.
Ges. p. 629.
—— (12) Weiterer Beitrag zur Kenntniss der fossilen Tertiärflora Bosniens.
Wiss. Mitt. aus Bosnien und der Herzegowina, Bd. xii. p. 593.
Engelhardt, H. and F. Kinkelin. (08) Oberpliocene Flora und Fauna des
Unter-Maintales. Abh. Senck. Naturforsch. Ges. Bd. xxix. Heft iii. p.
151.
Engler, A. (89) Engler and Prantl; Die Natürlichen Pflanzenfamilien, Teil ii.
Abt. i.
—— (95) Die Pflanzenwelt Öst Afrikas, etc. Th. C. Berlin.
—— (97) Engler and Prantl; Die Natürlichen Pflanzenfamilien. Nachtrag
zu Teilen ii–iv.
Essner, B. (86) Ueber den diagnostischen Werth der Anzahl und Höhe der
Markstrahlen bei den Coniferen. Abh. naturforsch. Ges. Halle, Bd. xvi.
p. 1.
Etheridge, R. (93) On the occurrence of a plant allied to Schizoneura in the
Hawkesbury Sandstone. Rec. Geol. Surv. New South Wales, vol. iii. pt.
iii, p. 74.
Page 652
Ettingshausen, C. von. (51) Ueber einige neue und interessante
Taeniopteris Arten aus den Sammlungen des Kais. Hof Mineralien
Cabinetes und der K.k. geol. Reichsanstalt. Naturwiss. Abh. W.
Haidinger, vol. iv. p. 95.
—— (52) Beitrag zur näheren Kenntniss der Flora der Wealdenperiode.
Abh. K.k. geol. Reichs. Wien, Bd. i. Abth. iii. No. 2, p. 1.
—— (522) Die Steinkohlenflora von Stradonitz. Ibid. Bd. i. Abth. iii. No. 4.
—— (55) Die Tertiäre Flora von Häring in Tirol. Ibid. Bd. ii. Abth. ii. No. 2.
—— (57) Die Fossile Flora von Köflach in Steiermark. Jahrb. K.k. geol.
Reichs. Bd. viii. p. 738.
—— (58) Beiträge zur Kenntniss der fossilen Flora von Sotzka in
Untersteiermark. Sitz. K. Akad. Wiss. Wien, Bd. xxviii. p. 471.
—— (67) Die Kreideflora von Niederschoena in Sachsen. Ibid. Bd. lv.
Abth. i. p. 235.
—— (672) Die fossile Flora des Tertiär-Beckens von Bilin. Denksch. Wiss.
Akad. Wien, Bd. xxvi. p. 79.
—— (70) Beitrag zur Kenntniss der Tertiärflora Steiermarks. Sitz. K. Akad.
Wien, Bd. lx. Abth. i. p. 17.
—— (72) Die Fossile Flora von Sagor in Krain. Denksch. Wiss. Akad. Wien,
Bd. xxxii. p. 32.
—— (78) Beitrag zur Erforschung der Phylogenie der Pflanzenarten. Ibid.
Bd. xxxviii. p. 65.
—— (79) Report on Phyto-Palaeontological Investigations of the Fossil
Flora of Sheppey. Proc. R. Soc. vol. xxix. p. 388.
—— (80) Report on Phyto-Palaeontological Investigations of the Fossil
Flora of Alum Bay. Ibid. vol. xxx. p. 228.
—— (85) Die Fossile Flora von Sagor in Krain. Denksch. Wiss. Akad. Wien,
Bd. l. p. 1.
—— (86) Beiträge zur Kenntniss der Tertiärflora Australiens. Ibid. Bd. liii.
p. 81.
—— (87) Beiträge zur Kenntniss der Fossile Flora Neuseelands. Denksch.
K. Akad. Wiss. Wien, Bd. liii. p. 3.
—— (88) Contributions to the Tertiary Flora of Australia. Mem. geol. Surv.
N.S.W. Pal. No. 2.
—— (882) Die Fossile Flora von Leoben in Steiermark. Denksch. K Akad.
Wiss. Wien, Bd. liv. Abth. i. p. 261.
Taeniopteris Arten aus den Sammlungen des Kais. Hof Mineralien
Cabinetes und der K.k. geol. Reichsanstalt. Naturwiss. Abh. W.
Haidinger, vol. iv. p. 95.
—— (52) Beitrag zur näheren Kenntniss der Flora der Wealdenperiode.
Abh. K.k. geol. Reichs. Wien, Bd. i. Abth. iii. No. 2, p. 1.
—— (522) Die Steinkohlenflora von Stradonitz. Ibid. Bd. i. Abth. iii. No. 4.
—— (55) Die Tertiäre Flora von Häring in Tirol. Ibid. Bd. ii. Abth. ii. No. 2.
—— (57) Die Fossile Flora von Köflach in Steiermark. Jahrb. K.k. geol.
Reichs. Bd. viii. p. 738.
—— (58) Beiträge zur Kenntniss der fossilen Flora von Sotzka in
Untersteiermark. Sitz. K. Akad. Wiss. Wien, Bd. xxviii. p. 471.
—— (67) Die Kreideflora von Niederschoena in Sachsen. Ibid. Bd. lv.
Abth. i. p. 235.
—— (672) Die fossile Flora des Tertiär-Beckens von Bilin. Denksch. Wiss.
Akad. Wien, Bd. xxvi. p. 79.
—— (70) Beitrag zur Kenntniss der Tertiärflora Steiermarks. Sitz. K. Akad.
Wien, Bd. lx. Abth. i. p. 17.
—— (72) Die Fossile Flora von Sagor in Krain. Denksch. Wiss. Akad. Wien,
Bd. xxxii. p. 32.
—— (78) Beitrag zur Erforschung der Phylogenie der Pflanzenarten. Ibid.
Bd. xxxviii. p. 65.
—— (79) Report on Phyto-Palaeontological Investigations of the Fossil
Flora of Sheppey. Proc. R. Soc. vol. xxix. p. 388.
—— (80) Report on Phyto-Palaeontological Investigations of the Fossil
Flora of Alum Bay. Ibid. vol. xxx. p. 228.
—— (85) Die Fossile Flora von Sagor in Krain. Denksch. Wiss. Akad. Wien,
Bd. l. p. 1.
—— (86) Beiträge zur Kenntniss der Tertiärflora Australiens. Ibid. Bd. liii.
p. 81.
—— (87) Beiträge zur Kenntniss der Fossile Flora Neuseelands. Denksch.
K. Akad. Wiss. Wien, Bd. liii. p. 3.
—— (88) Contributions to the Tertiary Flora of Australia. Mem. geol. Surv.
N.S.W. Pal. No. 2.
—— (882) Die Fossile Flora von Leoben in Steiermark. Denksch. K Akad.
Wiss. Wien, Bd. liv. Abth. i. p. 261.
Page 653
—— (90) Die Fossile Flora von Schoenegg bei Wies in Steiermark. Ibid.
Bd. lvii. p. 61.
Ewart, A. J. (08) On the longevity of seeds. Proc. R. Soc. Victoria, vol. xxi.
(N.S.), pt. i. p. 1.
Feistmantel, 0. (72) Beitrag zur Kenntniss der Ausdehnung des
sogennanten Wyřaner Gasschiefers und seiner Flora. Jahrb. K.k. geol.
Reichs. Wien, Bd. xxii. p. 289.
—— (76) Notes on the age of some Fossil Floras in India. Rec. Geol. Surv.
Ind. vol. ix. pt. iv. p. 115.
—— (762) Jurassic (Oolitic) Flora of Kach. Fossil Flora of the Gondwana
System, pt. i. vol. ii. 1880.
—— (77) Notes on Fossil Floras in India. Rec. Geol. Surv. Ind. vol. x. pt. iv.
p. 196.
—— (772) Jurassic (Liassic) Flora of the Rajmahal group in the Rajmahal
hills. Foss. Flor. Gond. Syst. vol. i. pt. ii.
—— (773) Jurassic (Liassic) Flora of the Rajmahal group from Golapili,
near Ellore, S. Godaveri. Ibid. pt. iii.
—— (774) Flora of the Jabalpur group (Upper Gondwanas) in the Son-
Narbada region. Ibid. vol. ii. pt. ii.
—— (775) Ueber die Gattung Williamsonia Carr. in Indien. Palaeontolog.
Beit. Palaeontograph. Suppl. iii. Lief. iii.
—— (79) Upper Gondwana Flora of the outliers on the Madras coast. Foss.
Flor. Gond. Syst. vol. i. pt. iv.
—— (792) The Flora of the Talchir-Karharbari beds. Ibid. vol. iii. pt. i.
—— (80) The Flora of the Damuda-Panchet Divisions. Ibid. vol. iii. pt. ii.
—— (802) Note on the fossil genera Noeggerathia Sternberg,
Noeggerathiopsis Feist. and Rhiptozamites Schmal. Rec. Geol. Surv.
India, vol. xiii. pt. i. p. 61.
—— (803) Further notes on the correlation of the Gondwana Flora with
other Floras. Rec. Geol. Surv. Ind. vol. xiii. pt. iii. p. 190.
—— (81) Palaeontological notes from the Hazáribágh and Lohárdagga
Districts. Ibid. vol. xiv. pt. iii. p. 241.
—— (812) The Flora of the Talchir-Karharbari beds. Foss. Flor. Gond. Syst.
vol. iii. pt. i.
—— (813) The Flora of the Damuda-Panchet Divisions. Ibid. vol. iii. pt. iii.
—— (82) The Fossil Flora of the South Rewah Gondwana Basin. Ibid. vol.
iv. pt. i.
Bd. lvii. p. 61.
Ewart, A. J. (08) On the longevity of seeds. Proc. R. Soc. Victoria, vol. xxi.
(N.S.), pt. i. p. 1.
Feistmantel, 0. (72) Beitrag zur Kenntniss der Ausdehnung des
sogennanten Wyřaner Gasschiefers und seiner Flora. Jahrb. K.k. geol.
Reichs. Wien, Bd. xxii. p. 289.
—— (76) Notes on the age of some Fossil Floras in India. Rec. Geol. Surv.
Ind. vol. ix. pt. iv. p. 115.
—— (762) Jurassic (Oolitic) Flora of Kach. Fossil Flora of the Gondwana
System, pt. i. vol. ii. 1880.
—— (77) Notes on Fossil Floras in India. Rec. Geol. Surv. Ind. vol. x. pt. iv.
p. 196.
—— (772) Jurassic (Liassic) Flora of the Rajmahal group in the Rajmahal
hills. Foss. Flor. Gond. Syst. vol. i. pt. ii.
—— (773) Jurassic (Liassic) Flora of the Rajmahal group from Golapili,
near Ellore, S. Godaveri. Ibid. pt. iii.
—— (774) Flora of the Jabalpur group (Upper Gondwanas) in the Son-
Narbada region. Ibid. vol. ii. pt. ii.
—— (775) Ueber die Gattung Williamsonia Carr. in Indien. Palaeontolog.
Beit. Palaeontograph. Suppl. iii. Lief. iii.
—— (79) Upper Gondwana Flora of the outliers on the Madras coast. Foss.
Flor. Gond. Syst. vol. i. pt. iv.
—— (792) The Flora of the Talchir-Karharbari beds. Ibid. vol. iii. pt. i.
—— (80) The Flora of the Damuda-Panchet Divisions. Ibid. vol. iii. pt. ii.
—— (802) Note on the fossil genera Noeggerathia Sternberg,
Noeggerathiopsis Feist. and Rhiptozamites Schmal. Rec. Geol. Surv.
India, vol. xiii. pt. i. p. 61.
—— (803) Further notes on the correlation of the Gondwana Flora with
other Floras. Rec. Geol. Surv. Ind. vol. xiii. pt. iii. p. 190.
—— (81) Palaeontological notes from the Hazáribágh and Lohárdagga
Districts. Ibid. vol. xiv. pt. iii. p. 241.
—— (812) The Flora of the Talchir-Karharbari beds. Foss. Flor. Gond. Syst.
vol. iii. pt. i.
—— (813) The Flora of the Damuda-Panchet Divisions. Ibid. vol. iii. pt. iii.
—— (82) The Fossil Flora of the South Rewah Gondwana Basin. Ibid. vol.
iv. pt. i.
Page 654
—— (86) The Fossil Flora of some of the Coalfields in Western Bengal.
Ibid. vol. iv. pl. ii.
—— (89) Übersichtliche Darstellung der geologisch-palaeontologischer
Verhältnisse Süd-Afrikas. Th. i. Abh. K. böhm. Ges. Wiss. [vii], Bd. iii.
Felix, J. (82) Beiträge zur Kenntniss fossiler Coniferen-Hölzer. Engler’s
Jahrb. Bd. iii. p. 260.
—— (84) Die Holzopale Ungarns in Palaeophytologischen Hinsicht. Mitt.
Jahrb. K. Ung. geol. Anst. Bd. vii.
—— (87) Untersuchungen über fossile Hölzer. Zeitsch. Deutsch. geol. Ges.
p. 517.
—— (94) Untersuchungen über fossile Hölzer. Ibid. Heft i. p. 79.
—— (96) Untersuchungen über fossile Hölzer. Ibid. Heft ii. p. 249.
Fiedler, H. (57) Die Fossile Früchte der Steinkohlen-formation. Acad.
Caes. Leop. Nov. Acta, Bd. xxvi. p. 239.
Fliche, P. (96) Étude sur la flore fossile de l’Argonne (Albien-
Cenomanien). Bull. soc. sci. Nancy.
—— (97) Note sur les nodules et bois minéralisés trouvés à St Parres-les-
vaudes (Aube) dans les grès verts infracrétacés. Mem. soc. Acad. de
l’Aube, tome lx.
—— (99) Note sur quelques fossiles végétaux de l’Oligocène dans les
Alpes Françaises. Bull. soc. géol. France [3], tome xxvii. p. 466.
—— (00) Contribution à la Flore fossile de la Haute-Marne (Infracrétacée).
Bull. soc. sci. Nancy.
—— (002) Note sur un bois fossile de Madagascar. Bull. soc. géol. France
[3]
, tome xxviii. p. 470.
—— (03) Note sur des bois silicifiés Permiens de la vallée de Celles
(Vosges).
—— (05) Note sur des bois fossiles de Madagascar. Bull. soc. géol. France
[4]
, tome v, p. 346.
—— (10) Flore Fossile du Trias en Lorraine et Franche-Comté avec des
considérations finales par M. R. Zeiller. Paris.
Fliche, P. and Bleicher. (82) Étude sur la flore de l’oolithe inférieure aux
environs de Nancy. Bull. soc. sci. Nancy.
Fliche, P. and R. Zeiller. (04) Note sur une florule Portlandienne des
environs de Boulogne-sur-mer. Bull. soc. géol. France [4], tome iv, p.
787.
Ibid. vol. iv. pl. ii.
—— (89) Übersichtliche Darstellung der geologisch-palaeontologischer
Verhältnisse Süd-Afrikas. Th. i. Abh. K. böhm. Ges. Wiss. [vii], Bd. iii.
Felix, J. (82) Beiträge zur Kenntniss fossiler Coniferen-Hölzer. Engler’s
Jahrb. Bd. iii. p. 260.
—— (84) Die Holzopale Ungarns in Palaeophytologischen Hinsicht. Mitt.
Jahrb. K. Ung. geol. Anst. Bd. vii.
—— (87) Untersuchungen über fossile Hölzer. Zeitsch. Deutsch. geol. Ges.
p. 517.
—— (94) Untersuchungen über fossile Hölzer. Ibid. Heft i. p. 79.
—— (96) Untersuchungen über fossile Hölzer. Ibid. Heft ii. p. 249.
Fiedler, H. (57) Die Fossile Früchte der Steinkohlen-formation. Acad.
Caes. Leop. Nov. Acta, Bd. xxvi. p. 239.
Fliche, P. (96) Étude sur la flore fossile de l’Argonne (Albien-
Cenomanien). Bull. soc. sci. Nancy.
—— (97) Note sur les nodules et bois minéralisés trouvés à St Parres-les-
vaudes (Aube) dans les grès verts infracrétacés. Mem. soc. Acad. de
l’Aube, tome lx.
—— (99) Note sur quelques fossiles végétaux de l’Oligocène dans les
Alpes Françaises. Bull. soc. géol. France [3], tome xxvii. p. 466.
—— (00) Contribution à la Flore fossile de la Haute-Marne (Infracrétacée).
Bull. soc. sci. Nancy.
—— (002) Note sur un bois fossile de Madagascar. Bull. soc. géol. France
[3]
, tome xxviii. p. 470.
—— (03) Note sur des bois silicifiés Permiens de la vallée de Celles
(Vosges).
—— (05) Note sur des bois fossiles de Madagascar. Bull. soc. géol. France
[4]
, tome v, p. 346.
—— (10) Flore Fossile du Trias en Lorraine et Franche-Comté avec des
considérations finales par M. R. Zeiller. Paris.
Fliche, P. and Bleicher. (82) Étude sur la flore de l’oolithe inférieure aux
environs de Nancy. Bull. soc. sci. Nancy.
Fliche, P. and R. Zeiller. (04) Note sur une florule Portlandienne des
environs de Boulogne-sur-mer. Bull. soc. géol. France [4], tome iv, p.
787.
Page 655
Fontaine, W. M. (93) Notes on some Fossil plants from the Trinity
Division of the Comanche series of Texas. Proc. U. S. Nat. Mus. vol.
xvi. p. 261.
Foxworthy, F. W. (11) Philippine Gymnosperms. Philipp. Journ. Sci. (C)
Botany, vol. vi. No. 3, p. 149.
Fraine, E. de. (12) On the structure and affinities of Sutcliffia, in the light
of a newly discovered specimen. Ann. Bot. vol. xxvi. p. 1031.
—— (14) On Medullosa centrofilis, a new species of Medullosa from the
Lower Coal Measures. Ibid. vol. xxviii. p. 251.
Fritel, P. H. and R. Vignier. (11) Étude anatomique de deux bois Éocènes.
Ann. sci. nat. [9], tome xiv. p. 63.
Fujii, K. (96) On the different views hitherto proposed regarding the
morphology of the flowers of Ginkgo biloba. Bot. Mag. Tokyo, vol. x.
No. 109, p. 13.
—— (10) Some remarks on the Cretaceous Fossil Flora and the causes of
extinction. Bot. Mag. Tokyo, vol. xxiv. No. 284, p. 197.
Fujioka, M. (13) Studien über den anatomischen Bau des Hölzes der
japanischen Nadelbäume. Journ. Coll. Agric. Imp. Univ. Tokyo, vol. iv.
No. 4, p. 201.
Gardner, J. S. (86) A monograph of the British Eocene Flora, vol. ii.
Gymnospermae. Palaeont. Soc. London.
—— (862) Second Report of the Committee appointed for the purpose of
reporting on the Fossil Plants of the Tertiary and Secondary beds of the
United Kingdom. Rep. of the 56th Meeting Brit. Assoc.
Geinitz, H. B. (42) Charakteristik der Schichten und Petrefacten des
Sächsischen Kreidegebirges. Heft iii. Dresden und Leipzig.
—— (62) Dyas oder die Zechstein-formation und das Rothliegende, Heft ii.
Leipzig.
—— (63) Über zwei neue Dyadische Pflanzen. Neues Jahrb. Min. p. 525.
—— (71) Über fossile Pflanzen aus der Steinkohlen-Formation am Altai.
Leipzig.
—— (73) Versteinerungen aus dem Brandschiefer der unteren Dyas von
Weissig bei Pillnitz in Sächsen. Neues Jahrb. Min. p. 681.
—— (75) Über neue Aufschlüsse im Brandschiefer der unteren Dyas von
Weissig bei Pillnitz in Sächsen. Ibid. p. 1.
—— (80) Nachträge zur Dyas I. Mittheil. aus dem K. Min.-geol. und
Praehist. Mus. Dresden, Heft 3.
Division of the Comanche series of Texas. Proc. U. S. Nat. Mus. vol.
xvi. p. 261.
Foxworthy, F. W. (11) Philippine Gymnosperms. Philipp. Journ. Sci. (C)
Botany, vol. vi. No. 3, p. 149.
Fraine, E. de. (12) On the structure and affinities of Sutcliffia, in the light
of a newly discovered specimen. Ann. Bot. vol. xxvi. p. 1031.
—— (14) On Medullosa centrofilis, a new species of Medullosa from the
Lower Coal Measures. Ibid. vol. xxviii. p. 251.
Fritel, P. H. and R. Vignier. (11) Étude anatomique de deux bois Éocènes.
Ann. sci. nat. [9], tome xiv. p. 63.
Fujii, K. (96) On the different views hitherto proposed regarding the
morphology of the flowers of Ginkgo biloba. Bot. Mag. Tokyo, vol. x.
No. 109, p. 13.
—— (10) Some remarks on the Cretaceous Fossil Flora and the causes of
extinction. Bot. Mag. Tokyo, vol. xxiv. No. 284, p. 197.
Fujioka, M. (13) Studien über den anatomischen Bau des Hölzes der
japanischen Nadelbäume. Journ. Coll. Agric. Imp. Univ. Tokyo, vol. iv.
No. 4, p. 201.
Gardner, J. S. (86) A monograph of the British Eocene Flora, vol. ii.
Gymnospermae. Palaeont. Soc. London.
—— (862) Second Report of the Committee appointed for the purpose of
reporting on the Fossil Plants of the Tertiary and Secondary beds of the
United Kingdom. Rep. of the 56th Meeting Brit. Assoc.
Geinitz, H. B. (42) Charakteristik der Schichten und Petrefacten des
Sächsischen Kreidegebirges. Heft iii. Dresden und Leipzig.
—— (62) Dyas oder die Zechstein-formation und das Rothliegende, Heft ii.
Leipzig.
—— (63) Über zwei neue Dyadische Pflanzen. Neues Jahrb. Min. p. 525.
—— (71) Über fossile Pflanzen aus der Steinkohlen-Formation am Altai.
Leipzig.
—— (73) Versteinerungen aus dem Brandschiefer der unteren Dyas von
Weissig bei Pillnitz in Sächsen. Neues Jahrb. Min. p. 681.
—— (75) Über neue Aufschlüsse im Brandschiefer der unteren Dyas von
Weissig bei Pillnitz in Sächsen. Ibid. p. 1.
—— (80) Nachträge zur Dyas I. Mittheil. aus dem K. Min.-geol. und
Praehist. Mus. Dresden, Heft 3.
Page 656
Gerry, E. (10) The distribution of the Bars of Sanio in the Coniferales. Ann.
Bot. vol. xxiv. p. 119.
Geyler, T. and F. Kinkelin. (90) Oberpliocän-Flora aus den Baugraben des
Klärbeckens bei Niederrad etc. Abh. Senck. Naturforsch. Ges. Bd. xv.
p. 1.
Gibbs, L. S. (12) On the Development of the female strobilus in
Podocarpus. Ann. Bot. vol. xxvi. p, 515.
Glück, H. (02) Eine fossile Fichte aus dem Neckerthal. Mitt. Grossh. Bad.
geolog. Landesanst. Bd. iv. Heft iv. p. 399.
Goc, M. J. le. (14) Observations on the centripetal and centrifugal xylems
in the petioles of Cycads. Ann. Bot. vol. xxviii. p. 183.
Goebel, K. (05) Organography of Plants. Pt. ii. Oxford.
Goeppert, H. R. (40) Über die neulichst im Basalttuff des hohen
Seelbachkopfes bei Siegen entdeckten bituminösen und versteinerten
Hölzer, so wie über die der Braunkohlenformation überhaupt. Arch. für
Min., Geog., etc. (Karsten und von Decken), Bd. xiv. p. 182.
—— (41) Über den Bernstein.... Uebersicht der Arbeiten und
Veränderungen der Schles. Ges. für Vaterländ. Kultur. Breslau.
—— (412) Taxites scalariformis, eine neue Art fossilen Holzes. Arch. für
Min., Geog., etc. Bd. xv. p. 727.
—— (44) Ueber die fossilen Cycadeen überhaupt, mit Rücksicht auf die in
Schlesien vorkommenden Arten. Uebersicht Arbeit. und Veränd.
Schlesisch. Ges. vat. Kult. 1843, p. 114. Breslau.
—— (45) F. Wimmer’s Flora von Schlesien nebst einer Uebersicht der
Fossilen Flora Schlesiens von H. R. Goeppert. Breslau.
—— (452) Description des végétaux fossiles recueillis par M. P. de
Tchihatcheff en Sibérie. Voyage scientifique dans l’Altai oriental, p.
379. Paris.
—— (46) Ueber die fossile Flora der mittleren Juraschichten in
Oberschlesien. Uebers. Arbeit. und Veränd. Schles. Ges. vat. Kultur im
Jahre 1845, Breslau, 1846, p. 139.
—— (47) Zur Flora des Quadersandsteins in Schlesien. Nachtrag. Nov. Act.
Ac. Caes. Leop.-Car. vol. xxii. p. 355.
—— (50) Monographie der fossilen Coniferen. Natuurkundige Verhand.
Holland. Maatschap. Wetenschappen Haarlem. Leiden.
—— (52) Fossile Flora des Übergangsgebirges. Nova Acta Caes. Leop.-
Carol. Nat. Cur. Bd. xx:i. (supplement).
Bot. vol. xxiv. p. 119.
Geyler, T. and F. Kinkelin. (90) Oberpliocän-Flora aus den Baugraben des
Klärbeckens bei Niederrad etc. Abh. Senck. Naturforsch. Ges. Bd. xv.
p. 1.
Gibbs, L. S. (12) On the Development of the female strobilus in
Podocarpus. Ann. Bot. vol. xxvi. p, 515.
Glück, H. (02) Eine fossile Fichte aus dem Neckerthal. Mitt. Grossh. Bad.
geolog. Landesanst. Bd. iv. Heft iv. p. 399.
Goc, M. J. le. (14) Observations on the centripetal and centrifugal xylems
in the petioles of Cycads. Ann. Bot. vol. xxviii. p. 183.
Goebel, K. (05) Organography of Plants. Pt. ii. Oxford.
Goeppert, H. R. (40) Über die neulichst im Basalttuff des hohen
Seelbachkopfes bei Siegen entdeckten bituminösen und versteinerten
Hölzer, so wie über die der Braunkohlenformation überhaupt. Arch. für
Min., Geog., etc. (Karsten und von Decken), Bd. xiv. p. 182.
—— (41) Über den Bernstein.... Uebersicht der Arbeiten und
Veränderungen der Schles. Ges. für Vaterländ. Kultur. Breslau.
—— (412) Taxites scalariformis, eine neue Art fossilen Holzes. Arch. für
Min., Geog., etc. Bd. xv. p. 727.
—— (44) Ueber die fossilen Cycadeen überhaupt, mit Rücksicht auf die in
Schlesien vorkommenden Arten. Uebersicht Arbeit. und Veränd.
Schlesisch. Ges. vat. Kult. 1843, p. 114. Breslau.
—— (45) F. Wimmer’s Flora von Schlesien nebst einer Uebersicht der
Fossilen Flora Schlesiens von H. R. Goeppert. Breslau.
—— (452) Description des végétaux fossiles recueillis par M. P. de
Tchihatcheff en Sibérie. Voyage scientifique dans l’Altai oriental, p.
379. Paris.
—— (46) Ueber die fossile Flora der mittleren Juraschichten in
Oberschlesien. Uebers. Arbeit. und Veränd. Schles. Ges. vat. Kultur im
Jahre 1845, Breslau, 1846, p. 139.
—— (47) Zur Flora des Quadersandsteins in Schlesien. Nachtrag. Nov. Act.
Ac. Caes. Leop.-Car. vol. xxii. p. 355.
—— (50) Monographie der fossilen Coniferen. Natuurkundige Verhand.
Holland. Maatschap. Wetenschappen Haarlem. Leiden.
—— (52) Fossile Flora des Übergangsgebirges. Nova Acta Caes. Leop.-
Carol. Nat. Cur. Bd. xx:i. (supplement).
Page 657
—— (53) Ueber die gegenwärtigen Verhältnisse der Paläontologie in
Schlesien, so wie über fossile Cycadeen. Denksch. Schles. Ges. für
Vaterländ. Kultur.
—— (65) Die fossile Flora der Permischen Formation. Palaeont. Bd. ii. p.
1.
—— (652) Über die fossile Kreideflora und ihre Leitpflanzen. Zeit.
Deutsch. geol. Ges. Bd. xvii. p. 638.
—— (66) Beiträge zur Kenntniss fossilen Cycadeen. Neues Jahrb. Min. p.
129.
—— (80) Beiträge zur Pathologie und Morphologie fossiler Stämme.
Palaeontol. [N.F.], Bd. viii. iii. p. 131.
—— (81) Revision meiner Arbeiten über die Stämme der fossilen
Coniferen, insbesondere der Araucariten, und über die
Descendenzlehre. Bot. Cent. Bd. v., vi. p. 378.
Goeppert, H. R. and G. Stenzel. (81) Die Medulloseae. Palaeontol. [N.F.],
Bd. viii. p. 113.
—— (88) Nachträge zur Kenntniss der Coniferenhölzer der Palaeozoischen
Formationen. Abh. K. Preuss. Akad. Wiss. Berlin.
Gomes, B. A. (65) Vegetaes Fosseis. Flora fossil do Terrens Carbonifero
das visinhanças dio Porto, serra do Bussaio, e moinho d’ordem
proximo a alcacer do Sal. Comm. geol. Portugal. Lisbon.
Gordon, Marjorie. (12) Ray-tracheids in Sequoia sempervirens. New Phyt.
vol. xi. p. 1.
gordon, w. t. (10) On a new species of Physostoma from the Lower
Carboniferous rocks of Pettycur (Fife). Proc. Camb. Phil. Soc. vol. xv.
pt. v. p. 395.
—— (12) On Rhetinangium Arberi, a new genus of Cycadofilices from the
Calciferous sandstone series. Trans. R. Soc. Edinb. vol. xlviii. pt. iv. p.
813.
Gothan, W. (05) Zur Anatomie lebender und fossiler Gymnospermer-
Hölzer. Abh. K. Preuss. geol. Landes. [N.F.], Heft xliv. p. 1.
—— (06) Die fossilen Coniferenhölzer von Senftenberg. Abh. K. Preuss.
Geol. Landesanst. Bergakad. [N.F.], Heft xlvi. p. 155.
—— (062) Fossile Hölzer aus dem Bathonien von Russisch-Polen. Verhand.
K. Russ. Min. Ges. zu St Petersburg [ii], Bd. xliv. Lief. i. p. 435.
—— (063) Piceoxylon Pseudotsugae als fossiles Holz. Potonié’s Abbild.
und Beschreib. Foss. Pflanz. Lief. iv. 80.
Schlesien, so wie über fossile Cycadeen. Denksch. Schles. Ges. für
Vaterländ. Kultur.
—— (65) Die fossile Flora der Permischen Formation. Palaeont. Bd. ii. p.
1.
—— (652) Über die fossile Kreideflora und ihre Leitpflanzen. Zeit.
Deutsch. geol. Ges. Bd. xvii. p. 638.
—— (66) Beiträge zur Kenntniss fossilen Cycadeen. Neues Jahrb. Min. p.
129.
—— (80) Beiträge zur Pathologie und Morphologie fossiler Stämme.
Palaeontol. [N.F.], Bd. viii. iii. p. 131.
—— (81) Revision meiner Arbeiten über die Stämme der fossilen
Coniferen, insbesondere der Araucariten, und über die
Descendenzlehre. Bot. Cent. Bd. v., vi. p. 378.
Goeppert, H. R. and G. Stenzel. (81) Die Medulloseae. Palaeontol. [N.F.],
Bd. viii. p. 113.
—— (88) Nachträge zur Kenntniss der Coniferenhölzer der Palaeozoischen
Formationen. Abh. K. Preuss. Akad. Wiss. Berlin.
Gomes, B. A. (65) Vegetaes Fosseis. Flora fossil do Terrens Carbonifero
das visinhanças dio Porto, serra do Bussaio, e moinho d’ordem
proximo a alcacer do Sal. Comm. geol. Portugal. Lisbon.
Gordon, Marjorie. (12) Ray-tracheids in Sequoia sempervirens. New Phyt.
vol. xi. p. 1.
gordon, w. t. (10) On a new species of Physostoma from the Lower
Carboniferous rocks of Pettycur (Fife). Proc. Camb. Phil. Soc. vol. xv.
pt. v. p. 395.
—— (12) On Rhetinangium Arberi, a new genus of Cycadofilices from the
Calciferous sandstone series. Trans. R. Soc. Edinb. vol. xlviii. pt. iv. p.
813.
Gothan, W. (05) Zur Anatomie lebender und fossiler Gymnospermer-
Hölzer. Abh. K. Preuss. geol. Landes. [N.F.], Heft xliv. p. 1.
—— (06) Die fossilen Coniferenhölzer von Senftenberg. Abh. K. Preuss.
Geol. Landesanst. Bergakad. [N.F.], Heft xlvi. p. 155.
—— (062) Fossile Hölzer aus dem Bathonien von Russisch-Polen. Verhand.
K. Russ. Min. Ges. zu St Petersburg [ii], Bd. xliv. Lief. i. p. 435.
—— (063) Piceoxylon Pseudotsugae als fossiles Holz. Potonié’s Abbild.
und Beschreib. Foss. Pflanz. Lief. iv. 80.
Page 658
—— (07) Über die Wandlungen der Hoftüpfelung bei den Gymnospermen
im Laufe der geologischen Epochen und ihre physiologische
Bedeutung. Sitz. Ges. Naturforsch. Freunde, No. 2, p. 13.
—— (072) Die Fossilen Hölzer von König Karls Land. K. Svensk.
Vetenskapsakad. Hand. Bd. xlii. No. 10, p. 1.
—— (08) Die Fossile Hölzer von der Seymour- und Snow Hill-Insel. Wiss.
Ergeb. Schwedis. Südpolar-Exped. 1901–03, Bd. iii. Lief. viii.
Stockholm.
—— (082) Die Frage der Klimadifferenzierung im Jura und in der
Kreideformation im Lichte paläobotanischer Tatsachen. Jahrb. K.
Preuss. Geol. Landes. für 1908, Bd. xxix. Th. ii. Heft 2, p. 220.
—— (09) Über Braunkohlenhölzer des rheinischen Tertiärs. Jahrb. K.
Preuss. geol. Land. Bd. xxx. Teil i. Heft 3, p. 516.
—— (10) Die Fossile Holzreste von Spitzbergen. K. Svensk.
Vetenskapsakad. Hand. Bd. xlv. No. viii.
—— (11) Über einige Permo-Carbonische Pflanzen von der unteren
Tunguska (Sibirien). Zeitsch. Deutsch. Geol. Ges. Bd. lxiii. Heft 4, p.
418.
—— (13) Die oberschlesische Steinkohlenflora. Teil i. K. Preuss. geol.
Landes. [N.F.], Heft lxxv.
Gourlie, W. (44) Notice of the Fossil Plants in the Glasgow Museum. Proc.
Phil. Soc. Glasgow, vol. i. 1844, p. 105.
Grand’Eury, C. (00) Sur les tiges debout, les souches et racines de
Cordaites. Compt. Rend. tome cxxx. (April 30).
—— (04) Sur les graines des Neuroptéridées. Compt. Rend. tome cxxxix. p.
23.
—— (042) Sur les graines des Neuroptéridées. Ibid. p. 782.
—— (05) Sur les Rhabdocarpus, les graines et l’évolution des Cordaitées.
Ibid. tome cxl. p. 995.
—— (052) Sur les graines de Sphenopteris, sur l’attribution des
Codonospermum et sur l’extréme variété des ‘graines de fougères.’
Ibid. p. 812.
—— (13) Recherches géobotaniques sur les forêts et sols fossiles et sur la
végétation et la flore houillères, en deux parties et dix livraisons. Pt. i.
Livr. ii., Paris et Liège.
Graner, (94) Die geographische Verbreitung der Holzarten. I. Die
Coniferen. Forstwissenschaft. Centralblatt, Berlin.
im Laufe der geologischen Epochen und ihre physiologische
Bedeutung. Sitz. Ges. Naturforsch. Freunde, No. 2, p. 13.
—— (072) Die Fossilen Hölzer von König Karls Land. K. Svensk.
Vetenskapsakad. Hand. Bd. xlii. No. 10, p. 1.
—— (08) Die Fossile Hölzer von der Seymour- und Snow Hill-Insel. Wiss.
Ergeb. Schwedis. Südpolar-Exped. 1901–03, Bd. iii. Lief. viii.
Stockholm.
—— (082) Die Frage der Klimadifferenzierung im Jura und in der
Kreideformation im Lichte paläobotanischer Tatsachen. Jahrb. K.
Preuss. Geol. Landes. für 1908, Bd. xxix. Th. ii. Heft 2, p. 220.
—— (09) Über Braunkohlenhölzer des rheinischen Tertiärs. Jahrb. K.
Preuss. geol. Land. Bd. xxx. Teil i. Heft 3, p. 516.
—— (10) Die Fossile Holzreste von Spitzbergen. K. Svensk.
Vetenskapsakad. Hand. Bd. xlv. No. viii.
—— (11) Über einige Permo-Carbonische Pflanzen von der unteren
Tunguska (Sibirien). Zeitsch. Deutsch. Geol. Ges. Bd. lxiii. Heft 4, p.
418.
—— (13) Die oberschlesische Steinkohlenflora. Teil i. K. Preuss. geol.
Landes. [N.F.], Heft lxxv.
Gourlie, W. (44) Notice of the Fossil Plants in the Glasgow Museum. Proc.
Phil. Soc. Glasgow, vol. i. 1844, p. 105.
Grand’Eury, C. (00) Sur les tiges debout, les souches et racines de
Cordaites. Compt. Rend. tome cxxx. (April 30).
—— (04) Sur les graines des Neuroptéridées. Compt. Rend. tome cxxxix. p.
23.
—— (042) Sur les graines des Neuroptéridées. Ibid. p. 782.
—— (05) Sur les Rhabdocarpus, les graines et l’évolution des Cordaitées.
Ibid. tome cxl. p. 995.
—— (052) Sur les graines de Sphenopteris, sur l’attribution des
Codonospermum et sur l’extréme variété des ‘graines de fougères.’
Ibid. p. 812.
—— (13) Recherches géobotaniques sur les forêts et sols fossiles et sur la
végétation et la flore houillères, en deux parties et dix livraisons. Pt. i.
Livr. ii., Paris et Liège.
Graner, (94) Die geographische Verbreitung der Holzarten. I. Die
Coniferen. Forstwissenschaft. Centralblatt, Berlin.
Page 659
Griffith, W. (59) Remarks on Gnetum. Trans. Linn. Soc. vol. xxii. pt. iv. p.
299.
Groom, P. (10) Remarks on the Oecology of Coniferae. Ann. Bot. vol. xxiv.
p. 241.
Groom, P. and W. Rushton. (13) The structure of the wood of East Indian
species of Pinus. Journ. Linn. Soc. vol. xli. p. 457.
Groppler, R. (94) Vergleichende Anatomie des Hölzes der Magnoliaceen.
Biblioth. Bot. Bd. vi. Heft 31. Stuttgart.
Grossenbacher, J. G. (15) Medullary spots and their cause. Bull. Torr. Bot.
Club, vol. xlii. p. 227.
Guppy, H. B. (06) Observations of a Naturalist in the Pacific between 1896
and 1899. London.
Gutbier, A. von. (49) Die Versteinerungen des Zechsteingebirges und
Rothliegenden oder des Permischen Systems in Sachsen. Dresden and
Leipzig.
Halle, T. G. (10) A Gymnosperm with Cordaitean-like leaves from the
Rhaetic beds of Scania. Arkiv för Bot. Upsala, Bd. ix. No. 14.
—— (12) On the occurrence of Dictyozamites in South America.
Palaeobot. Zeitsch. Bd. i. Heft i. p. 40.
—— (13) Some Mesozoic plant-bearing deposits in Patagonia and Tierra
del Fuego and their Floras. K. Svensk. Vetenskapsakad. Hand. Bd. li.
No. 3.
—— (132) The Mesozoic Flora of Graham Land. Wiss. Ergeb. Schwed.
südpolar. Exped. 1901–03, Bd. iii. Lief. 14, p. 1.
—— See Möller, H. J. and T. G. Halle (13).
—— (15) Some xerophytic leaf-structures in Mesozoic plants. Geol. Fören.
Stockholm Förhand. Bd. xxxvii. H. v. p. 493.
Hallier, H. (05) Provisional scheme of the Natural (Phylogenetic) system of
Flowering Plants. New Phyt. vol. iv. p. 151.
Harshberger, J. W. (98) Water-storage and conduction in Senecio praecox
DC. from Mexico. Contrib. Bot. Labt. (Univ. Pennsylvania), vol. ii.
No. 1.
—— (11) Phytogeographic Survey of N. America. (Die Veget. der Erde;
Engler and Drude, xiii. Leipzig.)
Harker, A. (06) The Geological structure of the Sgurr of Eigg. Quart.
Journ. Geol. Soc. vol. lxii. p. 40.
299.
Groom, P. (10) Remarks on the Oecology of Coniferae. Ann. Bot. vol. xxiv.
p. 241.
Groom, P. and W. Rushton. (13) The structure of the wood of East Indian
species of Pinus. Journ. Linn. Soc. vol. xli. p. 457.
Groppler, R. (94) Vergleichende Anatomie des Hölzes der Magnoliaceen.
Biblioth. Bot. Bd. vi. Heft 31. Stuttgart.
Grossenbacher, J. G. (15) Medullary spots and their cause. Bull. Torr. Bot.
Club, vol. xlii. p. 227.
Guppy, H. B. (06) Observations of a Naturalist in the Pacific between 1896
and 1899. London.
Gutbier, A. von. (49) Die Versteinerungen des Zechsteingebirges und
Rothliegenden oder des Permischen Systems in Sachsen. Dresden and
Leipzig.
Halle, T. G. (10) A Gymnosperm with Cordaitean-like leaves from the
Rhaetic beds of Scania. Arkiv för Bot. Upsala, Bd. ix. No. 14.
—— (12) On the occurrence of Dictyozamites in South America.
Palaeobot. Zeitsch. Bd. i. Heft i. p. 40.
—— (13) Some Mesozoic plant-bearing deposits in Patagonia and Tierra
del Fuego and their Floras. K. Svensk. Vetenskapsakad. Hand. Bd. li.
No. 3.
—— (132) The Mesozoic Flora of Graham Land. Wiss. Ergeb. Schwed.
südpolar. Exped. 1901–03, Bd. iii. Lief. 14, p. 1.
—— See Möller, H. J. and T. G. Halle (13).
—— (15) Some xerophytic leaf-structures in Mesozoic plants. Geol. Fören.
Stockholm Förhand. Bd. xxxvii. H. v. p. 493.
Hallier, H. (05) Provisional scheme of the Natural (Phylogenetic) system of
Flowering Plants. New Phyt. vol. iv. p. 151.
Harshberger, J. W. (98) Water-storage and conduction in Senecio praecox
DC. from Mexico. Contrib. Bot. Labt. (Univ. Pennsylvania), vol. ii.
No. 1.
—— (11) Phytogeographic Survey of N. America. (Die Veget. der Erde;
Engler and Drude, xiii. Leipzig.)
Harker, A. (06) The Geological structure of the Sgurr of Eigg. Quart.
Journ. Geol. Soc. vol. lxii. p. 40.
Page 660
—— (08) The Geology of the small Isles of Inverness-shire. Mem. Geol.
Surv. Scotland.
Harpe, P. de la. (62) See Bristow, H. W.
Hartz, N. (96) Planteforsteninger fra Cap Stewart i Østgrønland. Meddel.
om Grønland, xix. Copenhagen.
Hayata, A. (06) On Taiwania, a new genus of Coniferae from the Island of
Formosa. Journ. Linn. Soc. vol. xxxvii. p. 330.
—— (07) On Taiwania and its affinity to other genera. Bot. Mag. (Tokyo),
vol. xxi. p. 21.
—— (10) Botanical Survey by the Govt. of Formosa. Congr. Int. Bot.
(Bruxelles), p. 59.
Heer, O. (62) On the Fossil Flora of Bovey Tracey. Phil. Trans. R. Soc. vol.
clii. p. 1039.
—— (68) i. Die in Nordgrönland, auf der Melville-Insel, im Banksland, an
Mackenzie, im Island und in Spitzbergen entdeckten fossilen Pflanzen.
Flor. Foss. Arct. vol. i. Zürich.
—— (69) Beiträge zur Kreide-Flora. I. Flora von Moletein in Mähren. Neue
Denksch. Allgem. Schweiz. Ges. gesammt. Naturwiss. Bd. xxiii.
—— (71) iii. Die Miocene Flora und Fauna Spitzbergens. Flor. Foss. Arct.
vol. ii.
—— (712) Beiträge zur Kreide-Flora. II. Kreide Flora von Quedlinburg.
Neue Denksch. Allgem. Schweiz. Ges. gesammt. Naturwiss. Bd. xxiv.
—— (75) ii. Die Kreide-Flora der arctischen Zone. Flor. Foss. Arct. vol. iii.
—— (752) iii. Nachträge zur Miocenen Flora Grönlands. Ibid.
—— (76) Flora Fossilis Helvetiae. Zürich.
—— (762) Über Permische Pflanzen von Fünfkirchen in Ungarn. Mitt.
Jahrb. K. Ung. Geol. Anst. Bd. v.
—— (77) i. Beiträge zur fossilen Flora Spitzbergens. Flor. Foss. Arct. vol.
iv.
—— (772) ii. Beiträge zur Jura-Flora Ost Sibiriens und des Amurlandes.
Ibid.
—— (78) ii. Beiträge zur fossilen Flora Sibiriens und des Amurlandes. Ibid.
vol. iv.
—— (81) Contributions à la Flore du Portugal. Sect. Trav. Geol. Port.
(Lisbon).
—— (812) Zur Geschichte der Ginkgo-artigen Bäume. Engler’s Bot. Jahrb.
Bd. i. p. 1.
Surv. Scotland.
Harpe, P. de la. (62) See Bristow, H. W.
Hartz, N. (96) Planteforsteninger fra Cap Stewart i Østgrønland. Meddel.
om Grønland, xix. Copenhagen.
Hayata, A. (06) On Taiwania, a new genus of Coniferae from the Island of
Formosa. Journ. Linn. Soc. vol. xxxvii. p. 330.
—— (07) On Taiwania and its affinity to other genera. Bot. Mag. (Tokyo),
vol. xxi. p. 21.
—— (10) Botanical Survey by the Govt. of Formosa. Congr. Int. Bot.
(Bruxelles), p. 59.
Heer, O. (62) On the Fossil Flora of Bovey Tracey. Phil. Trans. R. Soc. vol.
clii. p. 1039.
—— (68) i. Die in Nordgrönland, auf der Melville-Insel, im Banksland, an
Mackenzie, im Island und in Spitzbergen entdeckten fossilen Pflanzen.
Flor. Foss. Arct. vol. i. Zürich.
—— (69) Beiträge zur Kreide-Flora. I. Flora von Moletein in Mähren. Neue
Denksch. Allgem. Schweiz. Ges. gesammt. Naturwiss. Bd. xxiii.
—— (71) iii. Die Miocene Flora und Fauna Spitzbergens. Flor. Foss. Arct.
vol. ii.
—— (712) Beiträge zur Kreide-Flora. II. Kreide Flora von Quedlinburg.
Neue Denksch. Allgem. Schweiz. Ges. gesammt. Naturwiss. Bd. xxiv.
—— (75) ii. Die Kreide-Flora der arctischen Zone. Flor. Foss. Arct. vol. iii.
—— (752) iii. Nachträge zur Miocenen Flora Grönlands. Ibid.
—— (76) Flora Fossilis Helvetiae. Zürich.
—— (762) Über Permische Pflanzen von Fünfkirchen in Ungarn. Mitt.
Jahrb. K. Ung. Geol. Anst. Bd. v.
—— (77) i. Beiträge zur fossilen Flora Spitzbergens. Flor. Foss. Arct. vol.
iv.
—— (772) ii. Beiträge zur Jura-Flora Ost Sibiriens und des Amurlandes.
Ibid.
—— (78) ii. Beiträge zur fossilen Flora Sibiriens und des Amurlandes. Ibid.
vol. iv.
—— (81) Contributions à la Flore du Portugal. Sect. Trav. Geol. Port.
(Lisbon).
—— (812) Zur Geschichte der Ginkgo-artigen Bäume. Engler’s Bot. Jahrb.
Bd. i. p. 1.
Page 661
—— (82) i. Flora fossilis Grönlandica. Flor. Foss. Arct. vol. vi.
—— (83) Flora fossilis Grönlandica. Ibid. vol. vii.
Helmhacher, R. (71) Sitzber. d. K. Böhm. Ges. Wiss. p. 81.
Henry, A. (06) See Elwes and Henry.
Herzfeld, S. (10) Die Entwicklungsgeschichte der weiblichen Blüte von
Cryptomeria japonica Don. Ein Beitrag zur Deutung der
Fruchtschuppe der Coniferen. Sitzber. Akad. Wiss. Wien, Bd. cxix. Abt.
i. p. 807.
Hick, T. (95) On Kaloxylon Hookeri Will. and Lyginodendron Oldhamium
Will. Mem. Proc. Manchester Lit. Phil. Soc. [4], vol. ix. p. 109.
Hilderbrand, F. (61) Die Verbreitung der Coniferen. Rhein. und Westphal.
Verhand. Bd. xviii. p. 199.
Hill, T. G. and E. de Fraine. (10) On the seedling structure of
Gymnosperms. IV. Ann. Bot. vol. xxiv. p. 319.
Hirase, S. (98) Études sur la fécundation et l’embryogenie du Ginkgo
biloba. Journ. Coll. Sci. Imp. Univ. Tokyo, vol. xii. p. 103.
Höhlke, F. (02) Ueber die Harzbehälter und die Harzbildung bei den
Polypodiaceen und einigen Phanerogamen. Beiheft Bot. Cent. Bd. xi.
p. 8.
Holden, H. S. (10) Note on a wounded Myeloxylon. New Phyt. vol. ix. p.
253.
Holden, Ruth. (13) Some fossil plants from Eastern Canada. Ann. Bot. vol.
xxvii. p. 243.
—— (132) Contributions to the anatomy of Mesozoic Conifers. No. 1.
Jurassic Coniferous wood from Yorkshire. Ann. Bot. vol. xxvii. p. 533.
—— (133) Cretaceous Pityoxyla from Cliffwood, New Jersey. Proc. Amer.
Acad. Arts and Sci. vol. xvi. p. 609.
—— (14) Contributions to the anatomy of Mesozoic Conifers. II.
Cretaceous Lignites from Cliffwood, N. Jersey. Bot. Gaz. vol. lviii. p.
168.
—— (142) On the relation between Cycadites and Pseudocycas. New Phyt.
vol. xiii. p. 334.
—— (15) A Jurassic wood from Scotland. Ibid. vol. xiv. p. 205.
—— (152) On the cuticles of some Indian Conifers. Bot. Gaz. vol. lx. p.
215.
Hollick, A. (97) The Cretaceous clay marl exposed at Cliffwood, N. J.
Trans. N. Y. Acad. Sci. vol. xvi. p. 124.
—— (83) Flora fossilis Grönlandica. Ibid. vol. vii.
Helmhacher, R. (71) Sitzber. d. K. Böhm. Ges. Wiss. p. 81.
Henry, A. (06) See Elwes and Henry.
Herzfeld, S. (10) Die Entwicklungsgeschichte der weiblichen Blüte von
Cryptomeria japonica Don. Ein Beitrag zur Deutung der
Fruchtschuppe der Coniferen. Sitzber. Akad. Wiss. Wien, Bd. cxix. Abt.
i. p. 807.
Hick, T. (95) On Kaloxylon Hookeri Will. and Lyginodendron Oldhamium
Will. Mem. Proc. Manchester Lit. Phil. Soc. [4], vol. ix. p. 109.
Hilderbrand, F. (61) Die Verbreitung der Coniferen. Rhein. und Westphal.
Verhand. Bd. xviii. p. 199.
Hill, T. G. and E. de Fraine. (10) On the seedling structure of
Gymnosperms. IV. Ann. Bot. vol. xxiv. p. 319.
Hirase, S. (98) Études sur la fécundation et l’embryogenie du Ginkgo
biloba. Journ. Coll. Sci. Imp. Univ. Tokyo, vol. xii. p. 103.
Höhlke, F. (02) Ueber die Harzbehälter und die Harzbildung bei den
Polypodiaceen und einigen Phanerogamen. Beiheft Bot. Cent. Bd. xi.
p. 8.
Holden, H. S. (10) Note on a wounded Myeloxylon. New Phyt. vol. ix. p.
253.
Holden, Ruth. (13) Some fossil plants from Eastern Canada. Ann. Bot. vol.
xxvii. p. 243.
—— (132) Contributions to the anatomy of Mesozoic Conifers. No. 1.
Jurassic Coniferous wood from Yorkshire. Ann. Bot. vol. xxvii. p. 533.
—— (133) Cretaceous Pityoxyla from Cliffwood, New Jersey. Proc. Amer.
Acad. Arts and Sci. vol. xvi. p. 609.
—— (14) Contributions to the anatomy of Mesozoic Conifers. II.
Cretaceous Lignites from Cliffwood, N. Jersey. Bot. Gaz. vol. lviii. p.
168.
—— (142) On the relation between Cycadites and Pseudocycas. New Phyt.
vol. xiii. p. 334.
—— (15) A Jurassic wood from Scotland. Ibid. vol. xiv. p. 205.
—— (152) On the cuticles of some Indian Conifers. Bot. Gaz. vol. lx. p.
215.
Hollick, A. (97) The Cretaceous clay marl exposed at Cliffwood, N. J.
Trans. N. Y. Acad. Sci. vol. xvi. p. 124.
Page 662
—— (04) Additions to the Palaeontology of the Cretaceous formation on
Long Island. No. II. Bull. N. Y. Bot. Gard. vol. iii. No. 11, p. 403.
—— (06) The Cretaceous Flora of southern N. Y. and New England. U. S.
Geol. Surv. Mon. vol. l.
—— (062) Systematic Palaeontology of the Pleistocene deposits of
Maryland. Contributions from the New York Bot. Gard. No. 85.
—— (12) Additions to the Palaeobotany of the Cretaceous formation on
Long Island. Bull. N. Y. Bot. Gard. vol. viii. No. 28, p. 154.
Hollick, A. and E. C. Jeffrey. (06) Affinities of certain Cretaceous plant-
remains commonly referred to the genera Dammara and
Brachyphyllum. Amer. Nat. vol. xl. p. 189.
Holmes, W. H. (78) Fossil Forests of the Volcanic Tertiary formations of
the Yellowstone National Park. Ann. Rep. Geol. Geogr. Surv. U.S.A. pt.
ii. p. 47.
Hooker, J. D. (52) Dacrydium laxifolium. Icones Plant. vol. v. pl. 815.
—— (60) Flora Tasmanica. London.
—— (62) On the Cedars of Lebanon, Taurus, Algeria, and India. Nat. Hist.
Rev. p. 11.
—— (63) On Welwitschia, a new genus of Gnetaceae. Trans. Linn. Soc. vol.
xxiv. p. 1.
Hooker, J. D. and E. W. Binney. (55) On the structure of certain limestone
nodules enclosed in seams of bituminous coal, with a description of
some Trigonocarpons contained in them. Phil. Trans. R. Soc. vol.
cxlix.
Hörich, O. (06) Potonié’s Abbildungen und Beschreibungen fossiler
Pflanzen-Reste. Lief. iv. 69, 70.
Howse, R. (88) A catalogue of Fossil Plants from the Hutton collection.
Nat. Hist. Trans. Northumberland, Durham, and Newcastle-upon-Tyne,
vol. x.
Hutchinson, A. H. (14) The male gametophyte of Abies. Bot. Gaz. vol. lvii.
p. 148.
—— (15) On the male gametophyte of Picea canadensis. Ibid. vol. lix. p.
287.
Jeffrey, E. C. (03) The comparative anatomy and phylogeny of the
Conifers. I. The genus Sequoia. Mem. Boston Soc. Nat. Hist. vol. v.
No. 10, p. 441.
Long Island. No. II. Bull. N. Y. Bot. Gard. vol. iii. No. 11, p. 403.
—— (06) The Cretaceous Flora of southern N. Y. and New England. U. S.
Geol. Surv. Mon. vol. l.
—— (062) Systematic Palaeontology of the Pleistocene deposits of
Maryland. Contributions from the New York Bot. Gard. No. 85.
—— (12) Additions to the Palaeobotany of the Cretaceous formation on
Long Island. Bull. N. Y. Bot. Gard. vol. viii. No. 28, p. 154.
Hollick, A. and E. C. Jeffrey. (06) Affinities of certain Cretaceous plant-
remains commonly referred to the genera Dammara and
Brachyphyllum. Amer. Nat. vol. xl. p. 189.
Holmes, W. H. (78) Fossil Forests of the Volcanic Tertiary formations of
the Yellowstone National Park. Ann. Rep. Geol. Geogr. Surv. U.S.A. pt.
ii. p. 47.
Hooker, J. D. (52) Dacrydium laxifolium. Icones Plant. vol. v. pl. 815.
—— (60) Flora Tasmanica. London.
—— (62) On the Cedars of Lebanon, Taurus, Algeria, and India. Nat. Hist.
Rev. p. 11.
—— (63) On Welwitschia, a new genus of Gnetaceae. Trans. Linn. Soc. vol.
xxiv. p. 1.
Hooker, J. D. and E. W. Binney. (55) On the structure of certain limestone
nodules enclosed in seams of bituminous coal, with a description of
some Trigonocarpons contained in them. Phil. Trans. R. Soc. vol.
cxlix.
Hörich, O. (06) Potonié’s Abbildungen und Beschreibungen fossiler
Pflanzen-Reste. Lief. iv. 69, 70.
Howse, R. (88) A catalogue of Fossil Plants from the Hutton collection.
Nat. Hist. Trans. Northumberland, Durham, and Newcastle-upon-Tyne,
vol. x.
Hutchinson, A. H. (14) The male gametophyte of Abies. Bot. Gaz. vol. lvii.
p. 148.
—— (15) On the male gametophyte of Picea canadensis. Ibid. vol. lix. p.
287.
Jeffrey, E. C. (03) The comparative anatomy and phylogeny of the
Conifers. I. The genus Sequoia. Mem. Boston Soc. Nat. Hist. vol. v.
No. 10, p. 441.
Page 663
—— (04) A fossil Sequoia from the Sierra Nevada. Bot. Gaz. vol. xxxviii. p.
321.
—— (05) The comparative anatomy and phylogeny of the Conifers. The
Abietineae. Mem. Boston Soc. Nat. Hist. vol. vi. No. 1.
—— (06) The wound Reactions of Brachyphyllum. Ann. Bot. vol. xx. p.
383.
—— (07) Araucariopitys, a new genus of Araucarians. Bot. Gaz. vol. xliv.
p. 435.
—— (08) Traumatic ray-tracheids in Cunninghamia sinensis. Ann. Bot. vol.
xxii. p. 593.
—— (082) On the structure of the leaf in Cretaceous Pines. Ibid. vol. xxii. p.
207.
—— (10) A new Prepinus from Martha’s Vineyard. Proc. Boston Soc. nat.
Hist. vol. xxxiv. No. 10, p. 333.
—— (102) A new Araucarian genus from the Triassic. Ibid. vol. xxxiv. No.
9, p. 325.
—— (103) On the affinities of Yezonia. Ann. Bot. vol. xxiv. p. 769.
—— (11) The affinities of Geinitzia gracillima. Bot. Gaz. vol. l. p. 21.
—— (12) The History, Comparative Anatomy and Evolution of the
Araucarioxylon type. Proc. Amer. Acad. Arts Sci. vol. xlviii. No. 13, p.
532.
—— (14) Spore-conditions in hybrids and the mutation hypothesis of de
Vries. Bot. Gaz. vol. lviii. p. 322.
Jeffrey, E. C. and M. A. Chrysler. (06) On Cretaceous Pityoxyla. Bot. Gaz.
vol. xlii. p. 1.
—— (062) The Lignites of Brandon. Contrib. from the Phanerogamic Labt.
of Harvard Univ. No. vi.
—— (07) The microgametophyte of the Podocarpineae. Amer. Nat. vol. xli.
No. 486, p. 355.
Jeffrey, E. C. and Ruth D. Cole. (16) Experimental Investigations on the
genus Drimys. Ann. Bot. vol. xxx. p. 359.
Jeffrey, E. C. and R. E. Torrey. (16) Ginkgo and the microsporangial
mechanisms of the seed plants. Bot. Gaz. vol. lxii. p. 281.
Johnson, T. (11) A seed-bearing Irish Pteridosperm, Crossotheca
Höninghausi Kidst. Sci. Proc. R. Dublin Soc. vol. xiii. p. 1.
—— (12) Heterangium hibernicum sp. nov. a seed-bearing Heterangium
from Co. Cork. Ibid. vol. xiii. No. 20.
321.
—— (05) The comparative anatomy and phylogeny of the Conifers. The
Abietineae. Mem. Boston Soc. Nat. Hist. vol. vi. No. 1.
—— (06) The wound Reactions of Brachyphyllum. Ann. Bot. vol. xx. p.
383.
—— (07) Araucariopitys, a new genus of Araucarians. Bot. Gaz. vol. xliv.
p. 435.
—— (08) Traumatic ray-tracheids in Cunninghamia sinensis. Ann. Bot. vol.
xxii. p. 593.
—— (082) On the structure of the leaf in Cretaceous Pines. Ibid. vol. xxii. p.
207.
—— (10) A new Prepinus from Martha’s Vineyard. Proc. Boston Soc. nat.
Hist. vol. xxxiv. No. 10, p. 333.
—— (102) A new Araucarian genus from the Triassic. Ibid. vol. xxxiv. No.
9, p. 325.
—— (103) On the affinities of Yezonia. Ann. Bot. vol. xxiv. p. 769.
—— (11) The affinities of Geinitzia gracillima. Bot. Gaz. vol. l. p. 21.
—— (12) The History, Comparative Anatomy and Evolution of the
Araucarioxylon type. Proc. Amer. Acad. Arts Sci. vol. xlviii. No. 13, p.
532.
—— (14) Spore-conditions in hybrids and the mutation hypothesis of de
Vries. Bot. Gaz. vol. lviii. p. 322.
Jeffrey, E. C. and M. A. Chrysler. (06) On Cretaceous Pityoxyla. Bot. Gaz.
vol. xlii. p. 1.
—— (062) The Lignites of Brandon. Contrib. from the Phanerogamic Labt.
of Harvard Univ. No. vi.
—— (07) The microgametophyte of the Podocarpineae. Amer. Nat. vol. xli.
No. 486, p. 355.
Jeffrey, E. C. and Ruth D. Cole. (16) Experimental Investigations on the
genus Drimys. Ann. Bot. vol. xxx. p. 359.
Jeffrey, E. C. and R. E. Torrey. (16) Ginkgo and the microsporangial
mechanisms of the seed plants. Bot. Gaz. vol. lxii. p. 281.
Johnson, T. (11) A seed-bearing Irish Pteridosperm, Crossotheca
Höninghausi Kidst. Sci. Proc. R. Dublin Soc. vol. xiii. p. 1.
—— (12) Heterangium hibernicum sp. nov. a seed-bearing Heterangium
from Co. Cork. Ibid. vol. xiii. No. 20.
Page 664
—— (14) Ginkgophyllum kiltorkense sp. nov. Ibid. vol. xiv. p. 169.
Johnston, R. H. (86) Fresh contributions to our knowledge of the Plants of
Mesozoic age in Tasmania. Papers and Proc. R. Soc. Tasmania for
1886, p. 160.
Johnstrup, M. F. (83) Recherches sur les fossiles appartenant aux
formations Crétacée et Miocène, sur la côte occidentale du Grønland.
Medd. om Grønland, vol. v.
Jones, W. S. (12) The structure of the Timbers of some common genera of
Coniferous trees. Quart. Journ. Forestry, April.
—— (13) The minute structure of the wood of Cupressus macrocarpa. Ibid.
—— (132) Ray-tracheids in Sequoia sempervirens and their pathological
character. Lampeter.
Karsten, G. (92) Beitrag zur Entwickelungsgeschichte einiger Gnetum
Arten. Bot. Zeit. p. 205.
—— (93) Untersuchungen über die Gattung Gnetum. I. Ann. Jard. Bot.
Buitenzorg, tome xi. p. 195.
—— (932) Zur Entwickelungsgeschichte der Gattung Gnetum. Cohn’s Beit.
Biol. Pflanz. vi. p. 337.
Kershaw, E. M. (09) The structure and development of the ovule of Myrica
Gale. Ann. Bot. vol. xxiii. p. 353.
—— (12) Structure and development of the ovule of Bowenia spectabilis.
Ibid. vol. xxvi. p. 625.
Kidston, R. (84) On a new species of Schützia from the Calciferous
sandstone of Scotland. Ann. Mag. Nat. Hist. vol. xiii. p. 77.
—— (86) Notes on some fossil plants collected by Mr R. Dunlop, Airdrie,
from the Lanarkshire coal-field. Trans. Geol. Soc. Glasgow, vol. viii. p.
47.
—— (90) The Yorkshire Carboniferous Flora. Trans. Yorks. Nat. Union, pt.
xiv.
—— (92) Notes on some fossil plants from the Lancashire Coal Measures.
Trans. Manchester Geol. Soc. pt. xiii. vol. xxi.
—— (04) On the Fructification of Neuropteris heterophylla Brongn. Phil.
Trans. R. Soc. vol. cxcvii. p. 1.
—— (042) On the Fructification of Neuropteris heterophylla Brongn. Proc.
R. Soc. vol. lxxii. p. 487.
—— (043) Some Fossil Plants collected by Mr A. Sinclair from the Ayrshire
coalfield. Kilmarnock Glenfield Ramblers Soc. Annals (1901–04), No.
Johnston, R. H. (86) Fresh contributions to our knowledge of the Plants of
Mesozoic age in Tasmania. Papers and Proc. R. Soc. Tasmania for
1886, p. 160.
Johnstrup, M. F. (83) Recherches sur les fossiles appartenant aux
formations Crétacée et Miocène, sur la côte occidentale du Grønland.
Medd. om Grønland, vol. v.
Jones, W. S. (12) The structure of the Timbers of some common genera of
Coniferous trees. Quart. Journ. Forestry, April.
—— (13) The minute structure of the wood of Cupressus macrocarpa. Ibid.
—— (132) Ray-tracheids in Sequoia sempervirens and their pathological
character. Lampeter.
Karsten, G. (92) Beitrag zur Entwickelungsgeschichte einiger Gnetum
Arten. Bot. Zeit. p. 205.
—— (93) Untersuchungen über die Gattung Gnetum. I. Ann. Jard. Bot.
Buitenzorg, tome xi. p. 195.
—— (932) Zur Entwickelungsgeschichte der Gattung Gnetum. Cohn’s Beit.
Biol. Pflanz. vi. p. 337.
Kershaw, E. M. (09) The structure and development of the ovule of Myrica
Gale. Ann. Bot. vol. xxiii. p. 353.
—— (12) Structure and development of the ovule of Bowenia spectabilis.
Ibid. vol. xxvi. p. 625.
Kidston, R. (84) On a new species of Schützia from the Calciferous
sandstone of Scotland. Ann. Mag. Nat. Hist. vol. xiii. p. 77.
—— (86) Notes on some fossil plants collected by Mr R. Dunlop, Airdrie,
from the Lanarkshire coal-field. Trans. Geol. Soc. Glasgow, vol. viii. p.
47.
—— (90) The Yorkshire Carboniferous Flora. Trans. Yorks. Nat. Union, pt.
xiv.
—— (92) Notes on some fossil plants from the Lancashire Coal Measures.
Trans. Manchester Geol. Soc. pt. xiii. vol. xxi.
—— (04) On the Fructification of Neuropteris heterophylla Brongn. Phil.
Trans. R. Soc. vol. cxcvii. p. 1.
—— (042) On the Fructification of Neuropteris heterophylla Brongn. Proc.
R. Soc. vol. lxxii. p. 487.
—— (043) Some Fossil Plants collected by Mr A. Sinclair from the Ayrshire
coalfield. Kilmarnock Glenfield Ramblers Soc. Annals (1901–04), No.
Page 665
iv. Kilmarnock.
—— (05) Preliminary Note on the occurrence of Microsporangia in organic
connection with the Foliage of Lyginodendron. Proc. R. Soc. vol.
lxxvi. p. 358.
—— (11) Les Végétaux houillers recueillis dans le Hainaut Belge. Mém.
Mus. Roy. d’hist. nat. Belg. tome iv.
—— (14) On the Fossil Flora of the Staffordshire coalfields. Pt. iii. The
Fossil Flora of the Westphalian series of the S. Staffs. coalfield. Trans.
R. Soc. Edinb. vol. l. pt. i. p. 73.
Kidston, R. and D. T. Gwynne-Vaughan. (12) On the Carboniferous Flora
of Berwickshire. Pt. i. Stenomyelon tuedianum Kidst. Trans. R. Soc.
Edinb. vol. xlviii. pt. ii. p. 263.
Kidston, R. and W. J. Jongmans. (11) Sur la Fructification de Neuropteris
obliqua Brongn. Arch. Neerl. sci. exact. nat. [iii. B], tome i. p. 25.
Kirby, J. W. (64) On some remains of Fishes and Plants from the ‘Upper
limestone’ of the Permian series of Durham. Quart. Journ. Geol. Soc.
vol. xx. p. 349.
Kirchner, O., E. T. Loew, and C. Schröter. (06) Die Coniferen und
Gnetaceen Mitteleuropas. Stuttgart.
Kirk, T. (89) The Forest Flora of New Zealand. Wellington.
Kirsch, S. (11) The Origin and Development of resin-canals in the
Coniferae, with special reference to the Development of Thyloses and
their correlation with the Thylosed strands of the Pteridophytes. Trans.
R. Soc. Canada, sect. iv. p. 43.
Kisch, Mabel H. (13) The Physiological Anatomy of the periderm of fossil
Lycopodiales. Ann. Bot. vol. xxvii. p. 281.
Kleeberg, A. (85) Die Markstrahlen der Coniferen. (Inaug. Diss.) Bot. Zeit.
Bd. xliii.
Klein, L. (81) Bau und Verzweigung einiger dorsiventral gebaute
Polypodiaceen. Nov. Act. K. Leop. Car. Deutsch. Akad. Naturforsch.
Bd. xlii. No. 7, p. 335.
Knowlton, F. H. (89) Description of the fossil woods and lignites from
Arkansas. Ann. Rep. Geol. Surv. Arkansas, vol. ii. p. 249.
—— (892) Fossil wood and Lignite of the Potomac formation. Bull. U. S.
Geol. Surv. No. 56.
—— (90) A Revision of the genus Araucarioxylon of Kraus, with the
compiled descriptions and partial synonymy of the species. Proc. U. S.
—— (05) Preliminary Note on the occurrence of Microsporangia in organic
connection with the Foliage of Lyginodendron. Proc. R. Soc. vol.
lxxvi. p. 358.
—— (11) Les Végétaux houillers recueillis dans le Hainaut Belge. Mém.
Mus. Roy. d’hist. nat. Belg. tome iv.
—— (14) On the Fossil Flora of the Staffordshire coalfields. Pt. iii. The
Fossil Flora of the Westphalian series of the S. Staffs. coalfield. Trans.
R. Soc. Edinb. vol. l. pt. i. p. 73.
Kidston, R. and D. T. Gwynne-Vaughan. (12) On the Carboniferous Flora
of Berwickshire. Pt. i. Stenomyelon tuedianum Kidst. Trans. R. Soc.
Edinb. vol. xlviii. pt. ii. p. 263.
Kidston, R. and W. J. Jongmans. (11) Sur la Fructification de Neuropteris
obliqua Brongn. Arch. Neerl. sci. exact. nat. [iii. B], tome i. p. 25.
Kirby, J. W. (64) On some remains of Fishes and Plants from the ‘Upper
limestone’ of the Permian series of Durham. Quart. Journ. Geol. Soc.
vol. xx. p. 349.
Kirchner, O., E. T. Loew, and C. Schröter. (06) Die Coniferen und
Gnetaceen Mitteleuropas. Stuttgart.
Kirk, T. (89) The Forest Flora of New Zealand. Wellington.
Kirsch, S. (11) The Origin and Development of resin-canals in the
Coniferae, with special reference to the Development of Thyloses and
their correlation with the Thylosed strands of the Pteridophytes. Trans.
R. Soc. Canada, sect. iv. p. 43.
Kisch, Mabel H. (13) The Physiological Anatomy of the periderm of fossil
Lycopodiales. Ann. Bot. vol. xxvii. p. 281.
Kleeberg, A. (85) Die Markstrahlen der Coniferen. (Inaug. Diss.) Bot. Zeit.
Bd. xliii.
Klein, L. (81) Bau und Verzweigung einiger dorsiventral gebaute
Polypodiaceen. Nov. Act. K. Leop. Car. Deutsch. Akad. Naturforsch.
Bd. xlii. No. 7, p. 335.
Knowlton, F. H. (89) Description of the fossil woods and lignites from
Arkansas. Ann. Rep. Geol. Surv. Arkansas, vol. ii. p. 249.
—— (892) Fossil wood and Lignite of the Potomac formation. Bull. U. S.
Geol. Surv. No. 56.
—— (90) A Revision of the genus Araucarioxylon of Kraus, with the
compiled descriptions and partial synonymy of the species. Proc. U. S.
Page 666
Mus. vol. xii. p. 601.
—— (93) The Laramie and the overlying Livingstone formation in
Montana. Report on the Flora. Bull. U. S. Geol. Surv. No. 105.
—— (99) Fossil Flora of the Yellowstone National Park. Monographs.
xxxii. U. S. Geol. Surv. pt. ii. chap. xiv.
—— (00) Flora of the Montana formation. Bull. U. S. Geol. Surv. No. 163.
—— (05) The geology of the Perry basin in South-eastern Maine, with a
chapter on the fossil plants. U. S. Geol. Surv. Prof. Papers, No. 35.
—— (11) The correct technical name for the Dragon tree of the Kentish
Rag. Geol. Mag. [v], vol. viii. p. 467.
—— (14) The Jurassic Flora of Cape Lisburne, Alaska. U. S. Geol. Surv.
Prof. Papers, No. 85-D, p. 39.
Kny, L. (10) Über die Verteilung des Holzparenchyma bei Abies pectinata
DC. Ann. Jard. Bot. Buit. [2], Suppl. iii. p. 645.
Koetlitz, R. (98) Observations on the geology of Franz Josef Land. Quart.
Journ. Geol. Soc. vol. liv. p. 620.
Kosmovsky, C. (92) Quelques mots sur les couches à végétaux fossiles
dans la Russie orientale et en Sibérie. Bull. Soc. Imp. Nat. Moscou
[N.S.], tome v. p. 170.
Kramer, A. (85) Beiträge zur Kenntniss der Entwickelungsgeschichte und
des anatomischen Baues der Fruchtblätter der Cupressineen und der
Placenten der Abietineen. Flora, xliii. p. 519.
Krasser, F. (91) Über die fossile Flora der rhätischen Schichten Persiens.
Sitzber. K. Akad. Wiss. Wien, Bd. c. Abth. i. p. 413.
—— (97) Constantine Freiherr von Ettingshausen. Oesterr. bot. Zeitsch.
Nos. 9 and 10.
—— (03) Konstantin von Ettingshausen’s Studien über die fossile Flora
von Ouricanga in Brasilien. Sitzber. K. Akad. Wiss. Wien, Bd. cxii. Abt.
i. p. 852.
—— (05) Fossile Pflanzen aus Transbaikalien der Mongolei und
Mandschurei. Denksch. K. Akad. Wiss. Wien, Bd. lxxviii. p. 589.
—— (09) Zur Kenntniss der fossilen Flora der Lunzer Schichten. Jahrb.
K.k. geol. Reichs. Wien, Bd. lix, Heft i. p. 101.
—— (12) Williamsonia in Sardinien. Sitzber. K. Akad. Wien, Bd. cxxi. Abt.
i. p. 944.
—— (13) Die fossile Flora der Williamsonien bergenden Juraschichten von
Sardinien. Ibid. Bd. cxxii.
—— (93) The Laramie and the overlying Livingstone formation in
Montana. Report on the Flora. Bull. U. S. Geol. Surv. No. 105.
—— (99) Fossil Flora of the Yellowstone National Park. Monographs.
xxxii. U. S. Geol. Surv. pt. ii. chap. xiv.
—— (00) Flora of the Montana formation. Bull. U. S. Geol. Surv. No. 163.
—— (05) The geology of the Perry basin in South-eastern Maine, with a
chapter on the fossil plants. U. S. Geol. Surv. Prof. Papers, No. 35.
—— (11) The correct technical name for the Dragon tree of the Kentish
Rag. Geol. Mag. [v], vol. viii. p. 467.
—— (14) The Jurassic Flora of Cape Lisburne, Alaska. U. S. Geol. Surv.
Prof. Papers, No. 85-D, p. 39.
Kny, L. (10) Über die Verteilung des Holzparenchyma bei Abies pectinata
DC. Ann. Jard. Bot. Buit. [2], Suppl. iii. p. 645.
Koetlitz, R. (98) Observations on the geology of Franz Josef Land. Quart.
Journ. Geol. Soc. vol. liv. p. 620.
Kosmovsky, C. (92) Quelques mots sur les couches à végétaux fossiles
dans la Russie orientale et en Sibérie. Bull. Soc. Imp. Nat. Moscou
[N.S.], tome v. p. 170.
Kramer, A. (85) Beiträge zur Kenntniss der Entwickelungsgeschichte und
des anatomischen Baues der Fruchtblätter der Cupressineen und der
Placenten der Abietineen. Flora, xliii. p. 519.
Krasser, F. (91) Über die fossile Flora der rhätischen Schichten Persiens.
Sitzber. K. Akad. Wiss. Wien, Bd. c. Abth. i. p. 413.
—— (97) Constantine Freiherr von Ettingshausen. Oesterr. bot. Zeitsch.
Nos. 9 and 10.
—— (03) Konstantin von Ettingshausen’s Studien über die fossile Flora
von Ouricanga in Brasilien. Sitzber. K. Akad. Wiss. Wien, Bd. cxii. Abt.
i. p. 852.
—— (05) Fossile Pflanzen aus Transbaikalien der Mongolei und
Mandschurei. Denksch. K. Akad. Wiss. Wien, Bd. lxxviii. p. 589.
—— (09) Zur Kenntniss der fossilen Flora der Lunzer Schichten. Jahrb.
K.k. geol. Reichs. Wien, Bd. lix, Heft i. p. 101.
—— (12) Williamsonia in Sardinien. Sitzber. K. Akad. Wien, Bd. cxxi. Abt.
i. p. 944.
—— (13) Die fossile Flora der Williamsonien bergenden Juraschichten von
Sardinien. Ibid. Bd. cxxii.
Page 667
Kraus, G. (64) Mikroskopische Untersuchungen über der Bau lebenden
Nadelhölzer. Würzb. Naturwiss. Zeitsch. Bd. v. p. 144.
—— (66) Über den Bau der Cycadeenfiedern. Prings. Jahrb. Bd. iv. p. 305.
—— (83) Beiträge zur Kenntniss fossiler Hölzer. I. Hölzer aus den
Schwefelgruben Siciliens. Abh. Naturf. Ges. Halle, Bd. xvi. p. 79.
—— (92) Beiträge zur Kenntniss fossiler Hölzer. Abh. Naturforsch. Ges.
Halle, Bd. xvii. p. 67.
—— (96) Physiologisches aus den Tropen. Ann. Jard. Bot. Buit. vol. xiii. p.
217.
Kräusel, R. (13) Beiträge zur Kenntniss der Hölzer aus der Schlesischen
Braunkohle. Teil i. (Inaug. Diss. Breslau.) Bot. Cent. Bd. cxxiii. p. 123.
Kryshtofovich, A. (10) Jurassic Plants from Ussuriland. Mem. Com. Geol.
[N.S.], Livr. 56.
—— (15) Plant remains from Jurassic lake-deposits of Transbaikalia. Mém.
Soc. Imp. Russe Mineralog. [2], li.
Kubart, B. (08) Pflanzenversteinerungen enthaltende Knollen aus dem
Ostrau-Karwiner Kohlenbecken. Sitzber. K. Akad. Wiss. Wien, Bd.
cxvii. Abt. i. p. 573.
—— (11) Corda’s sphaerosiderite aus dem Steinkohlenbecken Radnitz-
Braz in Böhmen nebst Bemerkungen über Chorionopteris
gleichenioides Corda. Ibid. Bd. cxx. Abt. i. p. 1035.
—— (112) Podocarpoxylon Schwendae, ein fossiles Holz von Altersee
(Oberösterreich). Österr. bot. Zeitsch. No. 5, p. 161.
—— (14) Über die Cycadofilicineen Heterangium und Lyginodendron aus
dem Ostrauer Kohlenbecken. Österr. bot. Zeitsch. No. i. ii. p. 8.
Kurtz, F. (03) Remarks upon Mr E. A. Arber’s communication on the
Clarke collection of Fossil Plants from New South Wales. Quart.
Journ. Geol. Soc. vol. lix. p. 25.
Kutorga, S. (42) Beitrag zur Palaeontologie Russlands. Verhand. Russ.-
Kais. Mineral. Ges. St Petersburg.
—— (44) Zweiter Beitrag zur Palaeontologie Russlands. Ibid. p. 62.
Land, W. J. G. (04) Spermatogenesis and Oogenesis in Ephedra trifurca.
Bot. Gaz. vol. xxxviii. p. 1.
Lang, W. H. (97) Studies in the Development and Morphology of
Cycadean sporangia. I. The microsporangia of Stangeria paradoxa.
Ann. Bot. vol. xi. p. 421.
Nadelhölzer. Würzb. Naturwiss. Zeitsch. Bd. v. p. 144.
—— (66) Über den Bau der Cycadeenfiedern. Prings. Jahrb. Bd. iv. p. 305.
—— (83) Beiträge zur Kenntniss fossiler Hölzer. I. Hölzer aus den
Schwefelgruben Siciliens. Abh. Naturf. Ges. Halle, Bd. xvi. p. 79.
—— (92) Beiträge zur Kenntniss fossiler Hölzer. Abh. Naturforsch. Ges.
Halle, Bd. xvii. p. 67.
—— (96) Physiologisches aus den Tropen. Ann. Jard. Bot. Buit. vol. xiii. p.
217.
Kräusel, R. (13) Beiträge zur Kenntniss der Hölzer aus der Schlesischen
Braunkohle. Teil i. (Inaug. Diss. Breslau.) Bot. Cent. Bd. cxxiii. p. 123.
Kryshtofovich, A. (10) Jurassic Plants from Ussuriland. Mem. Com. Geol.
[N.S.], Livr. 56.
—— (15) Plant remains from Jurassic lake-deposits of Transbaikalia. Mém.
Soc. Imp. Russe Mineralog. [2], li.
Kubart, B. (08) Pflanzenversteinerungen enthaltende Knollen aus dem
Ostrau-Karwiner Kohlenbecken. Sitzber. K. Akad. Wiss. Wien, Bd.
cxvii. Abt. i. p. 573.
—— (11) Corda’s sphaerosiderite aus dem Steinkohlenbecken Radnitz-
Braz in Böhmen nebst Bemerkungen über Chorionopteris
gleichenioides Corda. Ibid. Bd. cxx. Abt. i. p. 1035.
—— (112) Podocarpoxylon Schwendae, ein fossiles Holz von Altersee
(Oberösterreich). Österr. bot. Zeitsch. No. 5, p. 161.
—— (14) Über die Cycadofilicineen Heterangium und Lyginodendron aus
dem Ostrauer Kohlenbecken. Österr. bot. Zeitsch. No. i. ii. p. 8.
Kurtz, F. (03) Remarks upon Mr E. A. Arber’s communication on the
Clarke collection of Fossil Plants from New South Wales. Quart.
Journ. Geol. Soc. vol. lix. p. 25.
Kutorga, S. (42) Beitrag zur Palaeontologie Russlands. Verhand. Russ.-
Kais. Mineral. Ges. St Petersburg.
—— (44) Zweiter Beitrag zur Palaeontologie Russlands. Ibid. p. 62.
Land, W. J. G. (04) Spermatogenesis and Oogenesis in Ephedra trifurca.
Bot. Gaz. vol. xxxviii. p. 1.
Lang, W. H. (97) Studies in the Development and Morphology of
Cycadean sporangia. I. The microsporangia of Stangeria paradoxa.
Ann. Bot. vol. xi. p. 421.
Page 668
—— (00) Studies in the Development and Morphology of Cycadean
sporangia. II. The ovule of Stangeria paradoxa. Ibid. vol. xiv. p. 281.
Lange, T. (90) Beiträge zur Kenntniss der Flora des Aachener Sandes.
Zeitsch. Deutsch. geol. Ges. Bd. xlii. p. 658.
Laurent, L. (12) Flore fossile des Schistes de Manat (Puy-de-Dôme). Ann.
Mus. d’hist. nat. Marseille (Geol.), tome xiv. p. 3.
Lawson, A. A. (04) The gametophytes, fertilization, and embryo of
Cryptomeria japonica. Ann. Bot. vol. xviii. p. 417.
—— (09) The gametophytes and embryo of Pseudotsuga Douglasii. Ibid.
vol. xxiii. p. 163.
—— (10) The gametophytes and embryo of Sciadopitys verticillata. Ibid.
vol. xxiv. p. 403.
Lebour, G. A. (77) Illustrations of Fossil Plants; being an autotype
reproduction of selected drawings. London.
Lesquereux, L. (74) Contributions to the Fossil Flora of the Western
Territories. Pt. i. The Cretaceous Flora. Rep. U. S. Geol. Surv. Territ.
vol. vi.
—— (78) On the Cordaites and their related generic divisions, in the
Carboniferous formation of the United States. Proc. Amer. Phil. Soc.
(Philadelphia), vol. xvii. p. 315.
—— (83) Contributions to the Fossil Flora of the Western Territories. Pt. iii.
The Cretaceous and Tertiary Floras. U. S. Geol. Surv. Territ. vol. iii.
—— (91) The Flora of the Dakota group. Monographs U. S. Geol. Surv.
vol. xvii.
Leuthardt, F. (03) Die Keuper Flora von Neuewelt bei Basel. Abh.
Schweiz. palaeont. Ges. Bd. xxx. p. 1.
Lignier, O. (92) La nervation taenioptéridée de folioles de Cycas et le tissu
de transfusion. Bull. soc. Linn. Normandie [4], vol. vi. fasc. 1.
—— (94) La nervation des Cycadées est dichotomique. Assoc. Franç. pour
l’avancement de sci. (Caen).
—— (942) Végétaux Fossiles de Normandie. Structure et affinités du
Bennettites Morierei S. and M. sp. Mém. soc. Linn. Normand. tome
xviii. p. 1.
—— (95) Végétaux fossiles de Normandie. II. Contributions à la flore
liassique de Ste Honorine-la-Guillaume (Orne). Ibid. vol. xviii.
—— (01) Ibid. III. Étude anatomique du Cycadeoidea micromyela Mor.
Ibid. vol. xx. p. 331.
sporangia. II. The ovule of Stangeria paradoxa. Ibid. vol. xiv. p. 281.
Lange, T. (90) Beiträge zur Kenntniss der Flora des Aachener Sandes.
Zeitsch. Deutsch. geol. Ges. Bd. xlii. p. 658.
Laurent, L. (12) Flore fossile des Schistes de Manat (Puy-de-Dôme). Ann.
Mus. d’hist. nat. Marseille (Geol.), tome xiv. p. 3.
Lawson, A. A. (04) The gametophytes, fertilization, and embryo of
Cryptomeria japonica. Ann. Bot. vol. xviii. p. 417.
—— (09) The gametophytes and embryo of Pseudotsuga Douglasii. Ibid.
vol. xxiii. p. 163.
—— (10) The gametophytes and embryo of Sciadopitys verticillata. Ibid.
vol. xxiv. p. 403.
Lebour, G. A. (77) Illustrations of Fossil Plants; being an autotype
reproduction of selected drawings. London.
Lesquereux, L. (74) Contributions to the Fossil Flora of the Western
Territories. Pt. i. The Cretaceous Flora. Rep. U. S. Geol. Surv. Territ.
vol. vi.
—— (78) On the Cordaites and their related generic divisions, in the
Carboniferous formation of the United States. Proc. Amer. Phil. Soc.
(Philadelphia), vol. xvii. p. 315.
—— (83) Contributions to the Fossil Flora of the Western Territories. Pt. iii.
The Cretaceous and Tertiary Floras. U. S. Geol. Surv. Territ. vol. iii.
—— (91) The Flora of the Dakota group. Monographs U. S. Geol. Surv.
vol. xvii.
Leuthardt, F. (03) Die Keuper Flora von Neuewelt bei Basel. Abh.
Schweiz. palaeont. Ges. Bd. xxx. p. 1.
Lignier, O. (92) La nervation taenioptéridée de folioles de Cycas et le tissu
de transfusion. Bull. soc. Linn. Normandie [4], vol. vi. fasc. 1.
—— (94) La nervation des Cycadées est dichotomique. Assoc. Franç. pour
l’avancement de sci. (Caen).
—— (942) Végétaux Fossiles de Normandie. Structure et affinités du
Bennettites Morierei S. and M. sp. Mém. soc. Linn. Normand. tome
xviii. p. 1.
—— (95) Végétaux fossiles de Normandie. II. Contributions à la flore
liassique de Ste Honorine-la-Guillaume (Orne). Ibid. vol. xviii.
—— (01) Ibid. III. Étude anatomique du Cycadeoidea micromyela Mor.
Ibid. vol. xx. p. 331.
Page 669
—— (03) Le fruit du Williamsonia gigas Carr. Mém. soc. Linn. Normand.
vol. xxi. p. 19.
—— (032) La Fleur des Gnétacées est-celle intermédiaire entre celle des
Gymnospermes et celle des Angiospermes? Bull. soc. Linn. Normand.
[5]
, vol. vii. p. 55.
—— (04) Notes complémentaires sur la structure du Bennettites Morierei
S. and M. Bull. soc. Linn. Normand. [5], vol. viii. p. 3.
—— (06) Radiculites reticulatus, radicelle fossile de Séquoinée. Bull. soc.
bot. France, tome vi. [iii.], p. 193.
—— (07) Sur un moule litigieux de Williamsonia gigas (L. and H.) Carr.
Ibid. [6], vol. 1.
—— (072) Végétaux fossiles de Normandie. IV. Bois divers (sér. 1). Mém.
soc. Linn. Normand. vol. xxii. p. 239.
—— (09) Le Bennettites Morierei (S. and M.) Lignier ne serait-il pas
d’origine infracrétacée? Bull. soc. Linn. Normand. [6], vol. ii. p. 214.
—— (11) Le Bennettites Morierei (S. and M.) Lign. se reproduisait
probablement par parthénogénèse. Bull. soc. bot. France [4], tome xi. p.
224.
—— (112) Les “Radiculites reticulatus” Lign. soit probablement des
radicelles de Cordaitales. Assoc. Franç. Avanc. Sci. xl. (Dijon), p. 509.
[See also Lignier (06).]
—— (12) Stomates des écailles interséminales chez le Bennettites Morierei
(S. and M.). Ibid. tome xii. p. 425.
—— (13) Végétaux fossiles de Normandie. VII. Contributions à la Flore
Jurassique. Mém. soc. Linn. Normand. vol. xxiv. p. 69.
—— (132) Différenciation des tissus dans le Bourgeon végétatif du
Cordaites lingulatus B. Ren. Ann. sci. nat. [7], vol. xvii. p. 233.
Lignier, O. et A. Tison. (11) Les Gnétales sont des Angiospermes apétales.
Compt. Rend. Jan. 23.
—— (12) Les Gnétales, leurs fleurs et leur position systématique. Ann. sci.
nat. [N.S.].
—— (13) L’ovule tritégumenté des Gnetum est probablement un axe
d’inflorescence. Bull. soc. bot. France [4], tome xiii. p. 64.
—— (132) Un nouveau Sporange Séminiforme, Mittagia seminiformis, gen.
et sp. nov. Mém. Soc. Linn. Normandie, tome xxiv. p. 49.
Lima, W. de. (88) Flora Fossil de Portugal. Monographia do Genero
Dicranophyllum. Comm. dos Trab. geol. Portugal.
vol. xxi. p. 19.
—— (032) La Fleur des Gnétacées est-celle intermédiaire entre celle des
Gymnospermes et celle des Angiospermes? Bull. soc. Linn. Normand.
[5]
, vol. vii. p. 55.
—— (04) Notes complémentaires sur la structure du Bennettites Morierei
S. and M. Bull. soc. Linn. Normand. [5], vol. viii. p. 3.
—— (06) Radiculites reticulatus, radicelle fossile de Séquoinée. Bull. soc.
bot. France, tome vi. [iii.], p. 193.
—— (07) Sur un moule litigieux de Williamsonia gigas (L. and H.) Carr.
Ibid. [6], vol. 1.
—— (072) Végétaux fossiles de Normandie. IV. Bois divers (sér. 1). Mém.
soc. Linn. Normand. vol. xxii. p. 239.
—— (09) Le Bennettites Morierei (S. and M.) Lignier ne serait-il pas
d’origine infracrétacée? Bull. soc. Linn. Normand. [6], vol. ii. p. 214.
—— (11) Le Bennettites Morierei (S. and M.) Lign. se reproduisait
probablement par parthénogénèse. Bull. soc. bot. France [4], tome xi. p.
224.
—— (112) Les “Radiculites reticulatus” Lign. soit probablement des
radicelles de Cordaitales. Assoc. Franç. Avanc. Sci. xl. (Dijon), p. 509.
[See also Lignier (06).]
—— (12) Stomates des écailles interséminales chez le Bennettites Morierei
(S. and M.). Ibid. tome xii. p. 425.
—— (13) Végétaux fossiles de Normandie. VII. Contributions à la Flore
Jurassique. Mém. soc. Linn. Normand. vol. xxiv. p. 69.
—— (132) Différenciation des tissus dans le Bourgeon végétatif du
Cordaites lingulatus B. Ren. Ann. sci. nat. [7], vol. xvii. p. 233.
Lignier, O. et A. Tison. (11) Les Gnétales sont des Angiospermes apétales.
Compt. Rend. Jan. 23.
—— (12) Les Gnétales, leurs fleurs et leur position systématique. Ann. sci.
nat. [N.S.].
—— (13) L’ovule tritégumenté des Gnetum est probablement un axe
d’inflorescence. Bull. soc. bot. France [4], tome xiii. p. 64.
—— (132) Un nouveau Sporange Séminiforme, Mittagia seminiformis, gen.
et sp. nov. Mém. Soc. Linn. Normandie, tome xxiv. p. 49.
Lima, W. de. (88) Flora Fossil de Portugal. Monographia do Genero
Dicranophyllum. Comm. dos Trab. geol. Portugal.
Page 670
Lindley, J. See Murchison and Lyell (29).
Lingelsheim, A. (08) Über die Braunkohlenhölzer von Saarau. Jahres-Ber.
Schles. Ges. Vaterländ. Cultur. Bd. lxxxv.
Lloyd, F. E. (02) Vivipary in Podocarpus. Torreya, ii. p. 113.
Lomax, J. (02) On some features in relation to Lyginodendron oldhamium.
Ann. Bot. vol. xvi. p. 601.
Lotsy, J. (99) Contributions to the life-history of the genus Gnetum. Ann.
Jard. Bot. Buit. [2], vol. i. p. 46.
—— (09) Vorträge über botanische Stammesgeschichte. Bd. ii. Jena.
—— (11) Ibid. Bd. iii.
Ludwig, R. (61) Fossile Pflanzen aus der ältesten Abtheilung der
Rheinisch-Wetterauer Tertiär-Formation. Palaeontograph. Bd. viii. p.
39.
—— (69) Fossile Pflanzenreste aus den paläolithischen Formation der
Umgegend von Dillenburg, Biedenkopf und Friedberg und aus den
Saalfeldischen. Ibid. Bd. xvii. p. 105.
Lyon, H. L. (04) The Embryogeny of Ginkgo. Minnesota Bot. Stud. xxiii. p.
275.
McBride, T. H. (93) A new Cycad. Amer. Geologist, vol. xii. p. 248.
Mackie, S. J. (62) The Dragon Tree of the Kentish Rag. Geologist, vol. v.
p. 401.
McLean, R. C. (12) Two Fossil prothalli from the Lower Coal Measures.
New Phyt. vol. xi. p. 305.
McNab, W. R. (70) On the structure of a Lignite from the Old Red
Sandstone. Trans. Bot. Soc. Edinburgh, vol. x. p. 312.
Mahlert, A. (85) Beiträge zur Kenntniss der Anatomie der Laubblätter der
Coniferen mit besonderer Berücksichtigung des Spaltöffnungs-
Apparates. Bot. Cent. Bd. xxiv. p. 54.
Malloizel, G. and R. Zeiller. (N.D.) Bibliographie et tables
iconographiques (O. Heer). Stockholm.
Mansell-Pleydell, J. C. (85) Notes on a cone from the Inferior Oolite Beds
of Sherborne. Proc. Dorset Nat. Hist. Antiq. Field Club, vol. v. p. 141.
Mantell, G. (27) Illustrations of the Geology of Sussex. London.
—— (43) Description of some fossil plants from the chalk formation of the
south-east of England. Proc. Geol. Soc. vol. iv. p. 34.
—— (46) Description of some Fossil Fruits from the Chalk formation of
the south-east of England. Quart. Journ. Geol. Soc. vol. ii. p. 51.
Lingelsheim, A. (08) Über die Braunkohlenhölzer von Saarau. Jahres-Ber.
Schles. Ges. Vaterländ. Cultur. Bd. lxxxv.
Lloyd, F. E. (02) Vivipary in Podocarpus. Torreya, ii. p. 113.
Lomax, J. (02) On some features in relation to Lyginodendron oldhamium.
Ann. Bot. vol. xvi. p. 601.
Lotsy, J. (99) Contributions to the life-history of the genus Gnetum. Ann.
Jard. Bot. Buit. [2], vol. i. p. 46.
—— (09) Vorträge über botanische Stammesgeschichte. Bd. ii. Jena.
—— (11) Ibid. Bd. iii.
Ludwig, R. (61) Fossile Pflanzen aus der ältesten Abtheilung der
Rheinisch-Wetterauer Tertiär-Formation. Palaeontograph. Bd. viii. p.
39.
—— (69) Fossile Pflanzenreste aus den paläolithischen Formation der
Umgegend von Dillenburg, Biedenkopf und Friedberg und aus den
Saalfeldischen. Ibid. Bd. xvii. p. 105.
Lyon, H. L. (04) The Embryogeny of Ginkgo. Minnesota Bot. Stud. xxiii. p.
275.
McBride, T. H. (93) A new Cycad. Amer. Geologist, vol. xii. p. 248.
Mackie, S. J. (62) The Dragon Tree of the Kentish Rag. Geologist, vol. v.
p. 401.
McLean, R. C. (12) Two Fossil prothalli from the Lower Coal Measures.
New Phyt. vol. xi. p. 305.
McNab, W. R. (70) On the structure of a Lignite from the Old Red
Sandstone. Trans. Bot. Soc. Edinburgh, vol. x. p. 312.
Mahlert, A. (85) Beiträge zur Kenntniss der Anatomie der Laubblätter der
Coniferen mit besonderer Berücksichtigung des Spaltöffnungs-
Apparates. Bot. Cent. Bd. xxiv. p. 54.
Malloizel, G. and R. Zeiller. (N.D.) Bibliographie et tables
iconographiques (O. Heer). Stockholm.
Mansell-Pleydell, J. C. (85) Notes on a cone from the Inferior Oolite Beds
of Sherborne. Proc. Dorset Nat. Hist. Antiq. Field Club, vol. v. p. 141.
Mantell, G. (27) Illustrations of the Geology of Sussex. London.
—— (43) Description of some fossil plants from the chalk formation of the
south-east of England. Proc. Geol. Soc. vol. iv. p. 34.
—— (46) Description of some Fossil Fruits from the Chalk formation of
the south-east of England. Quart. Journ. Geol. Soc. vol. ii. p. 51.
Page 671
Marion, A. F. (84) Sur les caractères d’une Conifère tertiaire, voisine des
Dammarées (Doliostrobus Sternbergi). Compt. Rend. vol. xciv. p. 821.
Marsh, A. S. (14) Notes on the Anatomy of Stangeria paradoxa. New Phyt.
vol. xiii. p. 18.
Marty, P. (08) Sur la Flore fossile de Lugarde (Cantal). Compt. Rend. vol.
cxlvii. p. 395.
Maslen, A. J. (10) See Scott and Maslen.
—— (11) The structure of Mesoxylon Sutcliffi (Scott). Ann. Bot. vol. xxv. p.
381.
Massalongo, A. (59) Studii sulla Flora Fossile e geologia stratigrafica del
Senigalliese. Verona.
Massalongo, A. and G. Scarabelli. (58) Studii sulla Flora Fossile e
geologia stratigrafica del Senigalliese. Verona.
Masters, M. T. (91) Review of some points in the comparative
morphology, anatomy, and life-history of the Coniferae. Journ. Linn.
Soc. vol. xxviii. p. 236.
—— (93) Notes on the genera of Taxaceae and Coniferae. Ibid. vol. xxx. p.
1.
—— (00) Taxodium and Glyptostrobus. Journ. Bot. (February, 1900).
Matte, H. (04) Recherches sur l’appareil libéro-ligneux des Cycadées.
Caen.
—— (08) Sur le développement morphologique et anatomique des
Cycadacées. Mém. soc. Linn. Normand. tome xxiii.
Matthew, G. F. (10) Revision of the Flora of the Little River group. Trans.
R. Soc. Canada, sect. iv. vol. iii. [3], p. 77.
Mercklin, C. E. von. (55) Palaeodendrologicon Rossicum. St Petersburg.
Miller, H. (58) The Cruise of the Betsey. Edinburgh.
Miquel, F. A. W. (42) Monographia Cycadearum.
—— (47) Collectanea nova ad Cycadearum cognitionem. Linnaea, Bd. xix.
p. 411.
—— (51) Over de Rangschikking der fossiele Cycadeae. Tijdsch. Wiss. Nat.
Wet. vol. iv. p. 205.
—— (69) On the sexual organs of the Cycadaceae. Journ. Bot. vol. vii. p.
64.
Mirande, M. (05) Recherches sur le développement et l’anatomie de
Cassythacées. Ann. Sci. nat. [ix], vol. i. p. 181.
Dammarées (Doliostrobus Sternbergi). Compt. Rend. vol. xciv. p. 821.
Marsh, A. S. (14) Notes on the Anatomy of Stangeria paradoxa. New Phyt.
vol. xiii. p. 18.
Marty, P. (08) Sur la Flore fossile de Lugarde (Cantal). Compt. Rend. vol.
cxlvii. p. 395.
Maslen, A. J. (10) See Scott and Maslen.
—— (11) The structure of Mesoxylon Sutcliffi (Scott). Ann. Bot. vol. xxv. p.
381.
Massalongo, A. (59) Studii sulla Flora Fossile e geologia stratigrafica del
Senigalliese. Verona.
Massalongo, A. and G. Scarabelli. (58) Studii sulla Flora Fossile e
geologia stratigrafica del Senigalliese. Verona.
Masters, M. T. (91) Review of some points in the comparative
morphology, anatomy, and life-history of the Coniferae. Journ. Linn.
Soc. vol. xxviii. p. 236.
—— (93) Notes on the genera of Taxaceae and Coniferae. Ibid. vol. xxx. p.
1.
—— (00) Taxodium and Glyptostrobus. Journ. Bot. (February, 1900).
Matte, H. (04) Recherches sur l’appareil libéro-ligneux des Cycadées.
Caen.
—— (08) Sur le développement morphologique et anatomique des
Cycadacées. Mém. soc. Linn. Normand. tome xxiii.
Matthew, G. F. (10) Revision of the Flora of the Little River group. Trans.
R. Soc. Canada, sect. iv. vol. iii. [3], p. 77.
Mercklin, C. E. von. (55) Palaeodendrologicon Rossicum. St Petersburg.
Miller, H. (58) The Cruise of the Betsey. Edinburgh.
Miquel, F. A. W. (42) Monographia Cycadearum.
—— (47) Collectanea nova ad Cycadearum cognitionem. Linnaea, Bd. xix.
p. 411.
—— (51) Over de Rangschikking der fossiele Cycadeae. Tijdsch. Wiss. Nat.
Wet. vol. iv. p. 205.
—— (69) On the sexual organs of the Cycadaceae. Journ. Bot. vol. vii. p.
64.
Mirande, M. (05) Recherches sur le développement et l’anatomie de
Cassythacées. Ann. Sci. nat. [ix], vol. i. p. 181.
Page 672
Miyake, K. (06) Über die Spermatozoiden von Cycas revoluta. Ber.
Deutsch. bot. Ges. Bd. xxiv. p. 78.
—— (10) The Development of the gametophytes and embryogeny in
Cunninghamia sinensis. Beiheft Bot. Cent. Bd. xxxvii. Abt. i. Heft 1.
Mogan, L. (03) Untersuchungen über eine fossile Konifere. Sitzber. K.
Akad. Wiss. Wien, Bd. cxii. Abt. i. p. 829.
Mohl, H. von. (62) Einige anatomische und physiologische Bemerkungen
über das Holz der Baumwurzeln. Bot. Zeit. p. 225.
Möller, H. (03) Bidrag till Bornholms Fossila Flora (Rhät och Lias).
Gymnospermer. K. Svensk. Vetenskapsakad. Hand. Bd. xxxvi. No. vi.
Möller, H. J. and T. G. Halle. (13) The Fossil Flora of the Coal-bearing
deposits of south-eastern Scania. Arkiv Bot. (Stockholm), Bd. xiii. No.
7.
Morière, J. (69) Note sur deux végétaux trouvés dans le département du
Calvados. Mém. soc. Linn. Normand. vol. xv.
Morris, J. (40) Memoir to illustrate a Geological map of Cutch (Grant, C.
W.). Trans. Geol. Soc. [2], vol. v. pt. ii. p. 289.
—— (41) Remarks upon the Recent and Fossil Cycadeae. Ann. Mag. Nat.
Hist. vol. vii. p. 110.
—— (54) A Catalogue of British Fossils. London.
Müller, C. (90) Ueber die Balken in den Holzelementen der Coniferen. Ber.
Deutsch. bot. Ges. Bd. viii. p. 17.
Murchison, Sir R. and R. Harkness. (64) On the Permian rocks of the
North-west of England, and their extension into Scotland. Quart.
Journ. Geol. Soc. vol. xx. p. 144.
Murchison, Sir R. and C. Lyell. (29) On the Tertiary Freshwater
formations of Aix, in Provence, including the coal-field of Fuveau.
Description of plants by J. Lindley. Edinburgh New Phil. Journ. p.
287.
Nakamura, Y. (83) Ueber den anatomischen Bau des Hölzes der
wichtigsten Japanischen Coniferen. Unters. aus dem Forstbot. Instit.
zu München. iii. Berlin.
Nathorst, A. G. (75) Om en Cycadékotte från den rätiska formationens
lager vid Tinkarp i Skåne. Öfver. K. Vetenskapsakad. Förh. No. 10.
—— (78) Om Ginkgo crenata Brauns sp. från sandstenen vid Senstedt nära
Braunschweg. Ibid. No. 3.
—— (80) Några anmärkningar om Williamsonia, Carruthers. Ibid. No. 9.
Deutsch. bot. Ges. Bd. xxiv. p. 78.
—— (10) The Development of the gametophytes and embryogeny in
Cunninghamia sinensis. Beiheft Bot. Cent. Bd. xxxvii. Abt. i. Heft 1.
Mogan, L. (03) Untersuchungen über eine fossile Konifere. Sitzber. K.
Akad. Wiss. Wien, Bd. cxii. Abt. i. p. 829.
Mohl, H. von. (62) Einige anatomische und physiologische Bemerkungen
über das Holz der Baumwurzeln. Bot. Zeit. p. 225.
Möller, H. (03) Bidrag till Bornholms Fossila Flora (Rhät och Lias).
Gymnospermer. K. Svensk. Vetenskapsakad. Hand. Bd. xxxvi. No. vi.
Möller, H. J. and T. G. Halle. (13) The Fossil Flora of the Coal-bearing
deposits of south-eastern Scania. Arkiv Bot. (Stockholm), Bd. xiii. No.
7.
Morière, J. (69) Note sur deux végétaux trouvés dans le département du
Calvados. Mém. soc. Linn. Normand. vol. xv.
Morris, J. (40) Memoir to illustrate a Geological map of Cutch (Grant, C.
W.). Trans. Geol. Soc. [2], vol. v. pt. ii. p. 289.
—— (41) Remarks upon the Recent and Fossil Cycadeae. Ann. Mag. Nat.
Hist. vol. vii. p. 110.
—— (54) A Catalogue of British Fossils. London.
Müller, C. (90) Ueber die Balken in den Holzelementen der Coniferen. Ber.
Deutsch. bot. Ges. Bd. viii. p. 17.
Murchison, Sir R. and R. Harkness. (64) On the Permian rocks of the
North-west of England, and their extension into Scotland. Quart.
Journ. Geol. Soc. vol. xx. p. 144.
Murchison, Sir R. and C. Lyell. (29) On the Tertiary Freshwater
formations of Aix, in Provence, including the coal-field of Fuveau.
Description of plants by J. Lindley. Edinburgh New Phil. Journ. p.
287.
Nakamura, Y. (83) Ueber den anatomischen Bau des Hölzes der
wichtigsten Japanischen Coniferen. Unters. aus dem Forstbot. Instit.
zu München. iii. Berlin.
Nathorst, A. G. (75) Om en Cycadékotte från den rätiska formationens
lager vid Tinkarp i Skåne. Öfver. K. Vetenskapsakad. Förh. No. 10.
—— (78) Om Ginkgo crenata Brauns sp. från sandstenen vid Senstedt nära
Braunschweg. Ibid. No. 3.
—— (80) Några anmärkningar om Williamsonia, Carruthers. Ibid. No. 9.
Page 673
—— (81) Berättelse, afgifven till Kongl. Vetenskaps-Akad. Öfver. K.
Vetenskapsakad. Förhand. No. 1.
—— (86) Om Floran i Skånes kolförande Bildningar. I. Floran vid Bjuf.
Sver. geol. Unters. ser. C, Nos. 27, 33, 85 (1878–86).
—— (88) Nya anmärkningar om Williamsonia. Öfver. K. Vetenskapsakad.
Förh. No. 6.
—— (89) Sur la présence du Genre Dictyozamites, Old. dans les Couches
Jurassiques de Bornholm. Övers. K. Dansk. Vidensk. Selsk. Förhandl.
p. 96.
—— (93) Beiträge zur Geologie und Palaeontologie der Republik Mexico
(Felix und Link), Th. ii. Heft i. Leipzig.
—— (97) Zur Mesozoischen Flora Spitzbergens. K. Svensk.
Vetenskapsakad. Hand. Bd. xxx. No. 1, p. 5.
—— (972) Nachträgliche Bemerkungen über die Mesozoische Flora
Spitzbergens. Öfvers. K. Vet.-Akad. Förhand. No. 8.
—— (99) The Norwegian North Polar Expedition 1893–96. Scientific
Results, edit. F. Nansen. III. Fossil Plants from Franz Josef Land.
London and Christiania.
—— (02) Beiträge zur Kenntniss einiger Mesozoischen Cycadophyten. K.
Svensk. Vetenskapsakad. Hand. Bd. xxxvi. No. 4.
—— (06) Om några Ginkgovaxter från Kolgrufvorna vid Stabbarp i Skane.
Lunds Univ. Årsskrift [N.F.], Afd. ii. Bd. ii. No. 8.
—— (07) Über Trias- und Jurapflanzen von der Insel Kotelny. Mém. Acad.
Imp. Sci. St Petersburg, vol. xxi. No. 2.
—— (072) Paläobotanische Mitteilungen. 2. Die Kutikula der Blätter von
Dictyozamites Johnstrupi Nath. K. Svensk. Vetenskapsakad. Hand. Bd.
xlii. No. 5.
—— (073) Ibid. I. Pseudocycas, eine neue Cycadophytengattung aus den
Cenomanen Kreideablagerungen Grönlands.
—— (08) Über die Untersuchungen kutinisierter fossiler Pflanzenteile.
Paläobot. Mitt. 4–6. K. Svensk. Vetenskapsakad. Hand. Bd. xliii. No. 6,
p. 3.
—— (082) Paläobot. Mitt. 7. Über Palissya, Stachyotaxus and Palaeotaxus.
Ibid. Bd. xliii. No. 8.
—— (09) Paläobot. Mitt. 8. Über Williamsonia, Wielandia,
Cycadocephalus und Weltrichia. Ibid. Bd. xlv. No. 4.
Vetenskapsakad. Förhand. No. 1.
—— (86) Om Floran i Skånes kolförande Bildningar. I. Floran vid Bjuf.
Sver. geol. Unters. ser. C, Nos. 27, 33, 85 (1878–86).
—— (88) Nya anmärkningar om Williamsonia. Öfver. K. Vetenskapsakad.
Förh. No. 6.
—— (89) Sur la présence du Genre Dictyozamites, Old. dans les Couches
Jurassiques de Bornholm. Övers. K. Dansk. Vidensk. Selsk. Förhandl.
p. 96.
—— (93) Beiträge zur Geologie und Palaeontologie der Republik Mexico
(Felix und Link), Th. ii. Heft i. Leipzig.
—— (97) Zur Mesozoischen Flora Spitzbergens. K. Svensk.
Vetenskapsakad. Hand. Bd. xxx. No. 1, p. 5.
—— (972) Nachträgliche Bemerkungen über die Mesozoische Flora
Spitzbergens. Öfvers. K. Vet.-Akad. Förhand. No. 8.
—— (99) The Norwegian North Polar Expedition 1893–96. Scientific
Results, edit. F. Nansen. III. Fossil Plants from Franz Josef Land.
London and Christiania.
—— (02) Beiträge zur Kenntniss einiger Mesozoischen Cycadophyten. K.
Svensk. Vetenskapsakad. Hand. Bd. xxxvi. No. 4.
—— (06) Om några Ginkgovaxter från Kolgrufvorna vid Stabbarp i Skane.
Lunds Univ. Årsskrift [N.F.], Afd. ii. Bd. ii. No. 8.
—— (07) Über Trias- und Jurapflanzen von der Insel Kotelny. Mém. Acad.
Imp. Sci. St Petersburg, vol. xxi. No. 2.
—— (072) Paläobotanische Mitteilungen. 2. Die Kutikula der Blätter von
Dictyozamites Johnstrupi Nath. K. Svensk. Vetenskapsakad. Hand. Bd.
xlii. No. 5.
—— (073) Ibid. I. Pseudocycas, eine neue Cycadophytengattung aus den
Cenomanen Kreideablagerungen Grönlands.
—— (08) Über die Untersuchungen kutinisierter fossiler Pflanzenteile.
Paläobot. Mitt. 4–6. K. Svensk. Vetenskapsakad. Hand. Bd. xliii. No. 6,
p. 3.
—— (082) Paläobot. Mitt. 7. Über Palissya, Stachyotaxus and Palaeotaxus.
Ibid. Bd. xliii. No. 8.
—— (09) Paläobot. Mitt. 8. Über Williamsonia, Wielandia,
Cycadocephalus und Weltrichia. Ibid. Bd. xlv. No. 4.
Page 674
—— (092) Über die Gattung Nilssonia Brongn. mit besonderer
Berücksichtigung Schwedischen Arten. K. Svensk. Vetenskapsakad.
Hand. Bd. xliii. No. 12.
—— (10) Excursion C 3. Dépôts fossilifères (plantes) quaternaires de
Skâne. Compt. Rend. du XIe Congrès Géol. Internat. p. 1353.
—— (11) Paläobot. Mitt. 9. Neue Beiträge zur Kenntniss der Williamsonia-
Blüten. K. Svensk. Vetenskapsakad. Hand. Bd. xlvi. No. 4.
—— (112) Bemerkungen über Weltrichia Fr. Braun. Arkiv Bot. (K. Svensk.
Vetenskapsakad. Stockholm), Bd. ii. No. 7, p. 1.
—— (113) Fossil floras of the Arctic Regions as evidence of geological
climates. Geol. Mag. [v], vol. viii. p. 217.
—— (114) Paläobot. Mitt. 10. Über die Gattung Cycadocarpidium Nath.
nebst einigen Bemerkungen über Podozamites. K. Svensk.
Vetenskapsakad. Hand. Bd. xlvi. No. 8.
—— (12) Die Mikrosporophylle von Wielandiella. Arkiv Bot. Stockholm,
Bd. xii. No. 6, p. 1.
—— (122) Paläobot. Mitt. 11. Zur Kenntniss der Cycadocephalus Blüte. K.
Svensk. Vetenskapsakad. Hand. Bd. xlviii. No. 2.
—— (123) Einige paläobotanische Untersuchungsmethoden. Paläobot.
Zeitsch. Bd. i. Heft i. p. 26.
—— (13) How are the names Williamsonia and Wielandiella to be used? A
question of nomenclature. Geol. Fören. Stockholm Förh. Bd. xxxv. H.
vi. p. 361.
—— (132) Die pflanzenführenden Horizonte innerhalb der Grenzschichten
des Jura und der Kreide Spitzbergens. Geol. Fören. Stockholm Förh.
Bd. xxxv. H. iv. p. 273.
—— (14) Zur Fossilen Flora der Polarländer. Teil i. Lief. iv. Nachträge zur
Pälaozoischen Flora Spitzbergens. Stockholm.
—— (15) Zur Devonflora des westlichen Norwegens. Bergens Mus.
Aarbog, No. 7.
—— (152) Tertiäre Pflanzenreste aus Ellesmere-Land. Rep. second
Norwegian Arct. Exped. in the “Fram” 1898–02, No. 35. Kristiania.
Negri, G. (14) Sopra alcuni legni fossili del Gebel Tripolitano. Boll. Soc.
geol. Ital. vol. xxxiii. p. 321.
Nestler, A. (95) Ein Beitrag zur Anatomie der Cycadeenfiedern.
Pringsheim’s Jahrb. Bd. xxvii. p. 341.
Berücksichtigung Schwedischen Arten. K. Svensk. Vetenskapsakad.
Hand. Bd. xliii. No. 12.
—— (10) Excursion C 3. Dépôts fossilifères (plantes) quaternaires de
Skâne. Compt. Rend. du XIe Congrès Géol. Internat. p. 1353.
—— (11) Paläobot. Mitt. 9. Neue Beiträge zur Kenntniss der Williamsonia-
Blüten. K. Svensk. Vetenskapsakad. Hand. Bd. xlvi. No. 4.
—— (112) Bemerkungen über Weltrichia Fr. Braun. Arkiv Bot. (K. Svensk.
Vetenskapsakad. Stockholm), Bd. ii. No. 7, p. 1.
—— (113) Fossil floras of the Arctic Regions as evidence of geological
climates. Geol. Mag. [v], vol. viii. p. 217.
—— (114) Paläobot. Mitt. 10. Über die Gattung Cycadocarpidium Nath.
nebst einigen Bemerkungen über Podozamites. K. Svensk.
Vetenskapsakad. Hand. Bd. xlvi. No. 8.
—— (12) Die Mikrosporophylle von Wielandiella. Arkiv Bot. Stockholm,
Bd. xii. No. 6, p. 1.
—— (122) Paläobot. Mitt. 11. Zur Kenntniss der Cycadocephalus Blüte. K.
Svensk. Vetenskapsakad. Hand. Bd. xlviii. No. 2.
—— (123) Einige paläobotanische Untersuchungsmethoden. Paläobot.
Zeitsch. Bd. i. Heft i. p. 26.
—— (13) How are the names Williamsonia and Wielandiella to be used? A
question of nomenclature. Geol. Fören. Stockholm Förh. Bd. xxxv. H.
vi. p. 361.
—— (132) Die pflanzenführenden Horizonte innerhalb der Grenzschichten
des Jura und der Kreide Spitzbergens. Geol. Fören. Stockholm Förh.
Bd. xxxv. H. iv. p. 273.
—— (14) Zur Fossilen Flora der Polarländer. Teil i. Lief. iv. Nachträge zur
Pälaozoischen Flora Spitzbergens. Stockholm.
—— (15) Zur Devonflora des westlichen Norwegens. Bergens Mus.
Aarbog, No. 7.
—— (152) Tertiäre Pflanzenreste aus Ellesmere-Land. Rep. second
Norwegian Arct. Exped. in the “Fram” 1898–02, No. 35. Kristiania.
Negri, G. (14) Sopra alcuni legni fossili del Gebel Tripolitano. Boll. Soc.
geol. Ital. vol. xxxiii. p. 321.
Nestler, A. (95) Ein Beitrag zur Anatomie der Cycadeenfiedern.
Pringsheim’s Jahrb. Bd. xxvii. p. 341.
Page 675
Newberry, J. S. (54) New Fossil Plants from Ohio. Annals of Science;
including the Transactions of the American Association for the
Advancement of Science, vol. i. Cleveland, 1853–54, p. 116.
—— (73) Report of the Geological Survey of Ohio, vol. i.
—— (88) Rhaetic Plants from Honduras. Amer. Journ. Sci. vol. xxxvi. p.
342.
Newberry, J. S. and A. Hollick. (95) The Flora of the Amboy clays. U. S.
Geol. Surv. Monographs, vol. xxvi.
Newton, E. T. and J. J. H. Teall. (97) Notes on a collection of rocks and
fossils from Franz Josef Land, made by the Jackson-Harmsworth
Exped. during 1894–96. Quart. Journ. Geol. Soc. vol. liii. p. 477.
—— (98) Additional notes on rocks and fossils from Franz Josef Land.
Ibid. vol. liv. p. 646.
Noack, F. (87) Der Einfluss des Klimas auf die Cuticularisation und
Verholzung der Nadeln einiger Coniferen. Pringsheim’s Jahrb. Bd.
xviii. p. 519.
Noelle, W. (10) Studien zur vergleichenden Anatomie und Morphologie der
Koniferen Wurzeln mit Rücksicht auf die Systematik. Bot. Zeit. p. 169.
Norén, C. O. (08) Zur Kenntniss der Entwickelung von Saxegothaea
conspicua Lind. Svensk. Bot. Tids. Bd. ii. H. ii. p. 101.
Oliver, F. W. (02) On some points of apparent resemblance in certain Fossil
and Recent Gymnosperm seeds. New Phyt. vol. i. p. 145.
—— (03) The ovules of the older Gymnosperms. Ann. Bot. vol. xvii. p. 451.
—— (04) Notes on Trigonocarpus, Brongn. and Polylophospermum,
Brongn., two genera of Palaeozoic seeds. New Phyt. vol. iii. p. 96.
—— (05) Über die neuentdeckten Samen der Steinkohlenfarne. Biolog.
Centralblatt, Bd. xxv. No. 12, p. 401.
—— (06) The seed, a chapter in Evolution. Rep. 76th Meeting Brit. Assoc.
(York), p. 725.
—— (07) Note on the Palaeozoic seeds Trigonocarpus and
Polylophospermum. Ann. Bot. vol. xxi. p. 303.
—— (09) On Physostoma elegans Will. an archaic type of seed from the
Palaeozoic rocks. Ibid. vol. xxiii. p. 73.
—— (13) Makers of Modern Botany. A collection of Biographies by living
Botanists, edited by F. W. Oliver. Cambridge.
Oliver, F. W. and E. J. Salisbury. (11) On the structure and affinities of the
Conostoma group of Palaeozoic seeds. Ann. Bot. vol. xxv. p. 1.
including the Transactions of the American Association for the
Advancement of Science, vol. i. Cleveland, 1853–54, p. 116.
—— (73) Report of the Geological Survey of Ohio, vol. i.
—— (88) Rhaetic Plants from Honduras. Amer. Journ. Sci. vol. xxxvi. p.
342.
Newberry, J. S. and A. Hollick. (95) The Flora of the Amboy clays. U. S.
Geol. Surv. Monographs, vol. xxvi.
Newton, E. T. and J. J. H. Teall. (97) Notes on a collection of rocks and
fossils from Franz Josef Land, made by the Jackson-Harmsworth
Exped. during 1894–96. Quart. Journ. Geol. Soc. vol. liii. p. 477.
—— (98) Additional notes on rocks and fossils from Franz Josef Land.
Ibid. vol. liv. p. 646.
Noack, F. (87) Der Einfluss des Klimas auf die Cuticularisation und
Verholzung der Nadeln einiger Coniferen. Pringsheim’s Jahrb. Bd.
xviii. p. 519.
Noelle, W. (10) Studien zur vergleichenden Anatomie und Morphologie der
Koniferen Wurzeln mit Rücksicht auf die Systematik. Bot. Zeit. p. 169.
Norén, C. O. (08) Zur Kenntniss der Entwickelung von Saxegothaea
conspicua Lind. Svensk. Bot. Tids. Bd. ii. H. ii. p. 101.
Oliver, F. W. (02) On some points of apparent resemblance in certain Fossil
and Recent Gymnosperm seeds. New Phyt. vol. i. p. 145.
—— (03) The ovules of the older Gymnosperms. Ann. Bot. vol. xvii. p. 451.
—— (04) Notes on Trigonocarpus, Brongn. and Polylophospermum,
Brongn., two genera of Palaeozoic seeds. New Phyt. vol. iii. p. 96.
—— (05) Über die neuentdeckten Samen der Steinkohlenfarne. Biolog.
Centralblatt, Bd. xxv. No. 12, p. 401.
—— (06) The seed, a chapter in Evolution. Rep. 76th Meeting Brit. Assoc.
(York), p. 725.
—— (07) Note on the Palaeozoic seeds Trigonocarpus and
Polylophospermum. Ann. Bot. vol. xxi. p. 303.
—— (09) On Physostoma elegans Will. an archaic type of seed from the
Palaeozoic rocks. Ibid. vol. xxiii. p. 73.
—— (13) Makers of Modern Botany. A collection of Biographies by living
Botanists, edited by F. W. Oliver. Cambridge.
Oliver, F. W. and E. J. Salisbury. (11) On the structure and affinities of the
Conostoma group of Palaeozoic seeds. Ann. Bot. vol. xxv. p. 1.
Page 676
Oliver, F. W. and D. H. Scott. (03) On Lagenostoma Lomaxi, the seed of
Lyginodendron. Proc. R. Soc. vol. lxxi. p. 477.
—— (04) On the structure of the Palaeozoic seed Lagenostoma Lomaxi,
with a statement of the evidence upon which it is referred to
Lyginodendron. Phil. Trans. R. Soc. vol. cxcvii. p. 193.
Osborne, T. G. B. (09) The lateral roots of Amyelon radicans Will. and
their Mycorhiza. Ann. Bot. vol. xxiii. p. 603.
Palibin, J. (01) Quelques données relatives aux débris végétaux contenus
dans les sables blancs et les grès quartzeux de la Russie méridionale.
Bull. Com. Geol. tome xx. p. 447.
—— (04) Pflanzenreste vom Sichota-Alin Gebirge. Verhand. K. Russ.
Mineral. Ges. Bd. xlii. Lief. i. p. 31.
Patrick, J. S. (44) On the Fossil vegetables of the Sandstone of Ayrshire.
Ann. Mag. Nat. Hist. vol. xiii. p. 283.
Pavolini, A. F. (09) La Stangeria paradoxa Th. Moore. Nuov. Giorn. Bot.
Italiano [N.S.], vol. xvi. p. 335. Firenze.
Pax, F. (07) Beiträge zur fossilen Flora der Karpathen. Engler’s Bot. Jahrb.
Bd. xxxviii. p. 272.
Pearson, H. H. W. (06) Notes on South African Cycads. I. Trans. S. Afr.
Phil. Soc. vol. xvi. p. 341.
—— (062) Some observations on Welwitschia mirabilis. Phil. Trans. R. Soc.
vol. cxcviii. p. 265.
—— (09) Further observations on Welwitschia. Ibid. vol. cc. p. 331.
—— (12) On the Microsporangium and Microspore of Gnetum, with some
notes on the structure of the Inflorescence. Ann. Bot. vol. xxvi. p. 603.
—— (15) A note on the inflorescence and flower of Gnetum. Ann. Bolus
Herb. vol. i. pt. iv. p. 152.
—— (152) Notes on the Morphology of certain Structures concerned in
Reproduction in the genus Gnetum. Trans. Linn. Soc. vol. viii. pt. viii.
p. 311.
Penhallow, D. P. (91) See Dawson and Penhallow.
—— (97) Myelopteris topekensis n. sp. a new Carboniferous Plant. Bot.
Gaz. vol. xxiii. p. 15.
—— (00) Notes on the North American species of Dadoxylon. Trans. R.
Soc. Canada [2], vol. vi. sect. iv. p. 51.
—— (02) Notes on Cretaceous and Tertiary Plants of Canada. Trans. R.
Soc. Canada [2], vol. viii. sect. iv. p. 31.
Lyginodendron. Proc. R. Soc. vol. lxxi. p. 477.
—— (04) On the structure of the Palaeozoic seed Lagenostoma Lomaxi,
with a statement of the evidence upon which it is referred to
Lyginodendron. Phil. Trans. R. Soc. vol. cxcvii. p. 193.
Osborne, T. G. B. (09) The lateral roots of Amyelon radicans Will. and
their Mycorhiza. Ann. Bot. vol. xxiii. p. 603.
Palibin, J. (01) Quelques données relatives aux débris végétaux contenus
dans les sables blancs et les grès quartzeux de la Russie méridionale.
Bull. Com. Geol. tome xx. p. 447.
—— (04) Pflanzenreste vom Sichota-Alin Gebirge. Verhand. K. Russ.
Mineral. Ges. Bd. xlii. Lief. i. p. 31.
Patrick, J. S. (44) On the Fossil vegetables of the Sandstone of Ayrshire.
Ann. Mag. Nat. Hist. vol. xiii. p. 283.
Pavolini, A. F. (09) La Stangeria paradoxa Th. Moore. Nuov. Giorn. Bot.
Italiano [N.S.], vol. xvi. p. 335. Firenze.
Pax, F. (07) Beiträge zur fossilen Flora der Karpathen. Engler’s Bot. Jahrb.
Bd. xxxviii. p. 272.
Pearson, H. H. W. (06) Notes on South African Cycads. I. Trans. S. Afr.
Phil. Soc. vol. xvi. p. 341.
—— (062) Some observations on Welwitschia mirabilis. Phil. Trans. R. Soc.
vol. cxcviii. p. 265.
—— (09) Further observations on Welwitschia. Ibid. vol. cc. p. 331.
—— (12) On the Microsporangium and Microspore of Gnetum, with some
notes on the structure of the Inflorescence. Ann. Bot. vol. xxvi. p. 603.
—— (15) A note on the inflorescence and flower of Gnetum. Ann. Bolus
Herb. vol. i. pt. iv. p. 152.
—— (152) Notes on the Morphology of certain Structures concerned in
Reproduction in the genus Gnetum. Trans. Linn. Soc. vol. viii. pt. viii.
p. 311.
Penhallow, D. P. (91) See Dawson and Penhallow.
—— (97) Myelopteris topekensis n. sp. a new Carboniferous Plant. Bot.
Gaz. vol. xxiii. p. 15.
—— (00) Notes on the North American species of Dadoxylon. Trans. R.
Soc. Canada [2], vol. vi. sect. iv. p. 51.
—— (02) Notes on Cretaceous and Tertiary Plants of Canada. Trans. R.
Soc. Canada [2], vol. viii. sect. iv. p. 31.
Page 677
—— (03) Notes on Tertiary Plants. Ibid. vol. ix. sect. iv. p. 83.
—— (04) The anatomy of the North American Coniferales together with
certain exotic species from Japan and Australia. Amer. Nat. vol.
xxxviii. pp. 243, 523.
—— (07) A Manual of the North American Gymnosperms. Boston.
—— (08) Report on a collection of Fossil woods from the Cretaceous of
Alberta. The Ottawa Naturalist, vol. xxii. No. iv. p. 82.
Phillips, J. (71) The Geology of Oxford and the valley of the Thames.
Oxford.
Pilger, R. (03) Taxaceae. Das Pflanzenreich (A. Engler), Heft xviii. (iv. 5).
Leipzig.
Platen, P. (08) Untersuchungen fossiler Hölzer aus dem Westen der
Vereinigten Staaten von Nordamerika. Leipzig.
Pomel, A. (49) Matériaux pour servir à la flore fossile des terrains
jurassiques de la France. Amt. Ber. Versam. Ges. deutsch. Naturforsch.
und Ärzte. Aachen.
Porsch, C. (05) Der Spaltöffnungsapparat im Lichte der Phylogenie. Jena.
—— (10) Ephedra campylopoda C. A. Mey. eine entomophile
Gymnosperme. Ber. Deutsch. Bot. Ges. Bd. xxviii. p. 404.
Potonié, H. (88) Die fossile Pflanzen-Gattung Tylodendron. Jahrb. K.
Preuss. geol. Landes. p. 311.
—— (96) Ueber Autochthonie von Carbonkohlen-Flötze und der
Senftenberger Braunkohlen-Flötze. Ibid. (1895), p. 1.
—— (02) Fossile Hölzer aus der oberen Kreide Deutsch-Östafrikas. Die
Reisen des Bergassessors Dr Dantz in Deutsch-Östafrika in den Jahren
1898–00. Mitt. aus den deutschen Schutzgebieten, Bd. xv. Heft iv. p.
227.
—— (03) Pflanzenreste aus der Jura-formation. Durch Asien. Bd. iii. Lief. i.
Berlin.
—— (04) Abbildungen und Beschreibungen fossilen Pflanzen-Reste. Lief.
ii. No. 40. K. Preuss. geol. Landes. Bergakad.
Potonié, H. and C. Bernard. (04) Flore Dévonienne de l’étage H. de
Barrande. Leipzig.
Prankerd, T. L. (12) On the structure of the Palaeozoic seed Lagenostoma
ovoides Will. Journ. Linn. Soc. vol. xl. p. 461.
Prestwich, J. (54) On the structure of the strata between the London Clay
and the Chalk in the London and Hampshire Tertiary systems. Quart.
—— (04) The anatomy of the North American Coniferales together with
certain exotic species from Japan and Australia. Amer. Nat. vol.
xxxviii. pp. 243, 523.
—— (07) A Manual of the North American Gymnosperms. Boston.
—— (08) Report on a collection of Fossil woods from the Cretaceous of
Alberta. The Ottawa Naturalist, vol. xxii. No. iv. p. 82.
Phillips, J. (71) The Geology of Oxford and the valley of the Thames.
Oxford.
Pilger, R. (03) Taxaceae. Das Pflanzenreich (A. Engler), Heft xviii. (iv. 5).
Leipzig.
Platen, P. (08) Untersuchungen fossiler Hölzer aus dem Westen der
Vereinigten Staaten von Nordamerika. Leipzig.
Pomel, A. (49) Matériaux pour servir à la flore fossile des terrains
jurassiques de la France. Amt. Ber. Versam. Ges. deutsch. Naturforsch.
und Ärzte. Aachen.
Porsch, C. (05) Der Spaltöffnungsapparat im Lichte der Phylogenie. Jena.
—— (10) Ephedra campylopoda C. A. Mey. eine entomophile
Gymnosperme. Ber. Deutsch. Bot. Ges. Bd. xxviii. p. 404.
Potonié, H. (88) Die fossile Pflanzen-Gattung Tylodendron. Jahrb. K.
Preuss. geol. Landes. p. 311.
—— (96) Ueber Autochthonie von Carbonkohlen-Flötze und der
Senftenberger Braunkohlen-Flötze. Ibid. (1895), p. 1.
—— (02) Fossile Hölzer aus der oberen Kreide Deutsch-Östafrikas. Die
Reisen des Bergassessors Dr Dantz in Deutsch-Östafrika in den Jahren
1898–00. Mitt. aus den deutschen Schutzgebieten, Bd. xv. Heft iv. p.
227.
—— (03) Pflanzenreste aus der Jura-formation. Durch Asien. Bd. iii. Lief. i.
Berlin.
—— (04) Abbildungen und Beschreibungen fossilen Pflanzen-Reste. Lief.
ii. No. 40. K. Preuss. geol. Landes. Bergakad.
Potonié, H. and C. Bernard. (04) Flore Dévonienne de l’étage H. de
Barrande. Leipzig.
Prankerd, T. L. (12) On the structure of the Palaeozoic seed Lagenostoma
ovoides Will. Journ. Linn. Soc. vol. xl. p. 461.
Prestwich, J. (54) On the structure of the strata between the London Clay
and the Chalk in the London and Hampshire Tertiary systems. Quart.
Page 678
Journ. Geol. Soc. vol. x. p. 75.
Raciborski, M. (91) Flora Retycka Pólnocnego Stoku Gór
Świętokrzyskich. Rozprawy Wydzialu Akad. Umiej. Krakowie, tom.
xxiii.
—— (92) Przyczynek do Flory Retyckiej Polski. Ibid. tom. xxii. p. 1.
—— (922) Cycadeoidea Niedźwiedzkii nov. sp. Akad. wiss. Krak. Oktober
1892.
Radais, M. (94) L’anatomie comparée du fruit des Conifères. Ann. Sci. nat.
[7]
, vol. xix. p. 165.
Ratte, F. (87) Note on two new fossil plants from the Wianametta shales.
Proc. Linn. Soc. N.S.W. [2], vol. i. p. 1078.
—— (88) Additional evidence on Fossil Salisburiae from Australia. Proc.
Linn. Soc. N.S.W. [2], vol. ii. p. 159.
Rattray, C. (13) Notes on the pollination of some South African Cycads.
Trans. R. Soc. S. Africa, vol. iii. p. 259.
Reid, Clement and Eleanor M. Reid. (08) On the Preglacial Flora of
Britain. Journ. Linn. Soc. vol. xxxviii. p. 206.
—— (10) The Lignites of Bovey Tracey. Phil. Trans. R. Soc. vol. cci. p.
161.
—— (15) The Pliocene Floras of the Dutch-Prussian border. Meded.
Rijksopsporing Delfstoffen, No. 6. The Hague.
Renault, B. (79) Sur un nouveau groupe de tiges fossiles silicifiées de
l’époque houillière. Compt. Rend. tome lxxxviii. p. 35.
—— (80) Sur une nouvelle espèce de Poroxylon. Compt. Rend. tome xci. p.
860.
—— (802) Cours de Botanique fossile. Tome i. Paris.
—— (83) Cours de Botanique fossile. Tome iii.
—— (85) Cours de Botanique fossile. Tome iv.
—— (87) Note sur le Clathropodium Morieri. Bull. soc. Linn. Normand. [4],
vol. i. p. 3.
—— (88) Les Plantes fossiles. Paris.
—— (89) Sur un nouveau genre fossile de tige cycadéenne. Compt. Rend.
vol. cix. p. 1173.
—— (96) Note sur le genre Métacordaite. Soc. d’hist. nat. d’Autun.
Renault, B. and R. Zeiller. (85) Sur un nouveau type de Cordaitée. Compt.
Rend. vol. c. p. 867.
—— (86) Sur quelques Cycadées houillières. Ibid. vol. cii. p. 325.
Raciborski, M. (91) Flora Retycka Pólnocnego Stoku Gór
Świętokrzyskich. Rozprawy Wydzialu Akad. Umiej. Krakowie, tom.
xxiii.
—— (92) Przyczynek do Flory Retyckiej Polski. Ibid. tom. xxii. p. 1.
—— (922) Cycadeoidea Niedźwiedzkii nov. sp. Akad. wiss. Krak. Oktober
1892.
Radais, M. (94) L’anatomie comparée du fruit des Conifères. Ann. Sci. nat.
[7]
, vol. xix. p. 165.
Ratte, F. (87) Note on two new fossil plants from the Wianametta shales.
Proc. Linn. Soc. N.S.W. [2], vol. i. p. 1078.
—— (88) Additional evidence on Fossil Salisburiae from Australia. Proc.
Linn. Soc. N.S.W. [2], vol. ii. p. 159.
Rattray, C. (13) Notes on the pollination of some South African Cycads.
Trans. R. Soc. S. Africa, vol. iii. p. 259.
Reid, Clement and Eleanor M. Reid. (08) On the Preglacial Flora of
Britain. Journ. Linn. Soc. vol. xxxviii. p. 206.
—— (10) The Lignites of Bovey Tracey. Phil. Trans. R. Soc. vol. cci. p.
161.
—— (15) The Pliocene Floras of the Dutch-Prussian border. Meded.
Rijksopsporing Delfstoffen, No. 6. The Hague.
Renault, B. (79) Sur un nouveau groupe de tiges fossiles silicifiées de
l’époque houillière. Compt. Rend. tome lxxxviii. p. 35.
—— (80) Sur une nouvelle espèce de Poroxylon. Compt. Rend. tome xci. p.
860.
—— (802) Cours de Botanique fossile. Tome i. Paris.
—— (83) Cours de Botanique fossile. Tome iii.
—— (85) Cours de Botanique fossile. Tome iv.
—— (87) Note sur le Clathropodium Morieri. Bull. soc. Linn. Normand. [4],
vol. i. p. 3.
—— (88) Les Plantes fossiles. Paris.
—— (89) Sur un nouveau genre fossile de tige cycadéenne. Compt. Rend.
vol. cix. p. 1173.
—— (96) Note sur le genre Métacordaite. Soc. d’hist. nat. d’Autun.
Renault, B. and R. Zeiller. (85) Sur un nouveau type de Cordaitée. Compt.
Rend. vol. c. p. 867.
—— (86) Sur quelques Cycadées houillières. Ibid. vol. cii. p. 325.
Page 679
Rendle, A. B. (96) Gymnospermae. The Plants of Milanji, Nyasa-Land,
collected by Mr A. Whyte. Trans. Linn. Soc. vol. iv. [2], p. 60.
—— (04) The Classification of Flowering plants. Vol. i. Cambridge.
Renier, A. (07) Trois espèces nouvelles, Sphenopteris Dumonti, S. Corneti
et Dicranophyllum Richiri du Houiller sans Houille de Baudour,
Hainaut. Ann. soc. géol. Belg. vol. xxxiv. Mém. p. 181.
—— (10) Documents pour l’étude de la paléontologie du terrain houiller.
Liège.
—— (102) Paléontologie du Terrain Houiller. Liège.
Renner, O. (04) Über Zwitterblüthen bei Juniperus communis. Flora, Bd.
xcii. p. 92.
Richards, J. T. (84) On Scottish Fossil Cycadaceous leaves contained in
the Hugh Miller Collection. Proc. R. Phys. Soc. Edinburgh.
Robertson, Agnes. (02) Notes on the anatomy of Macrozamia heteromera
Moore. Proc. Camb. Phil. Soc. vol. xii. pt. i. p. 1.
—— (04) Studies in the Morphology of Torreya californica Torrey. New
Phyt. vol. iii. p. 205.
—— (06) Some points in the Morphology of Phyllocladus alpinus Hook.
Ann. Bot. vol. xx. p. 259.
—— (07) The Taxoideae; a phylogenetic study. New Phyt. vol. vi. p. 92.
Rosen, F. (11) Die biologische Stellung der abessinischen Baumlobelie
(Lobelia Rhynchopetalum). Beit. Biol. Pflanzen. Cohn und Rosen, Bd.
x. Heft ii. p. 265.
Rothert, W. (99) Ueber parenchymatische Tracheiden und Harzgänge im
Mark von Cephalotaxus-Arten. Ber. deutsch. bot. Ges. Bd. xvii. p. 275.
Rushton, W. (15) Structure of the wood of Himalayan Junipers. Journ.
Linn. Soc. vol. xliii. p. 1.
—— (16) The Development of ‘Sanio’s Bars’ in Pinus Inops. Ann. Bot. vol.
xxx. p. 419.
Russow, E. (72) Vergleichende Untersuchungen der Leitbündel-
Kryptogamen. Mém. l’Acad. Imp. Sci. St Pétersbourg [vii], tome xix.
p. 1.
—— (83) Zur Kenntniss des Holzes, insonderheit des Coniferenholzes. Bot.
Cent. Bd. xiii. p. 29.
Salisbury, E. J. (13) Methods of Palaeobotanical reconstruction. Ann. Bot.
vol. xxvii. p. 273.
collected by Mr A. Whyte. Trans. Linn. Soc. vol. iv. [2], p. 60.
—— (04) The Classification of Flowering plants. Vol. i. Cambridge.
Renier, A. (07) Trois espèces nouvelles, Sphenopteris Dumonti, S. Corneti
et Dicranophyllum Richiri du Houiller sans Houille de Baudour,
Hainaut. Ann. soc. géol. Belg. vol. xxxiv. Mém. p. 181.
—— (10) Documents pour l’étude de la paléontologie du terrain houiller.
Liège.
—— (102) Paléontologie du Terrain Houiller. Liège.
Renner, O. (04) Über Zwitterblüthen bei Juniperus communis. Flora, Bd.
xcii. p. 92.
Richards, J. T. (84) On Scottish Fossil Cycadaceous leaves contained in
the Hugh Miller Collection. Proc. R. Phys. Soc. Edinburgh.
Robertson, Agnes. (02) Notes on the anatomy of Macrozamia heteromera
Moore. Proc. Camb. Phil. Soc. vol. xii. pt. i. p. 1.
—— (04) Studies in the Morphology of Torreya californica Torrey. New
Phyt. vol. iii. p. 205.
—— (06) Some points in the Morphology of Phyllocladus alpinus Hook.
Ann. Bot. vol. xx. p. 259.
—— (07) The Taxoideae; a phylogenetic study. New Phyt. vol. vi. p. 92.
Rosen, F. (11) Die biologische Stellung der abessinischen Baumlobelie
(Lobelia Rhynchopetalum). Beit. Biol. Pflanzen. Cohn und Rosen, Bd.
x. Heft ii. p. 265.
Rothert, W. (99) Ueber parenchymatische Tracheiden und Harzgänge im
Mark von Cephalotaxus-Arten. Ber. deutsch. bot. Ges. Bd. xvii. p. 275.
Rushton, W. (15) Structure of the wood of Himalayan Junipers. Journ.
Linn. Soc. vol. xliii. p. 1.
—— (16) The Development of ‘Sanio’s Bars’ in Pinus Inops. Ann. Bot. vol.
xxx. p. 419.
Russow, E. (72) Vergleichende Untersuchungen der Leitbündel-
Kryptogamen. Mém. l’Acad. Imp. Sci. St Pétersbourg [vii], tome xix.
p. 1.
—— (83) Zur Kenntniss des Holzes, insonderheit des Coniferenholzes. Bot.
Cent. Bd. xiii. p. 29.
Salisbury, E. J. (13) Methods of Palaeobotanical reconstruction. Ann. Bot.
vol. xxvii. p. 273.
Page 680
—— (14) On the structure and relationship of Trigonocarpus shorensis.
Ann. Bot. vol. xxviii. p. 39.
Sanday, Elizabeth. (07) See Berridge and Sanday.
Sandberger, F. von. (64) Die Flora der oberen Steinkohlenformation im
badischer Schwarzwalde. Verh. Nat. Ver. Carlsruhe, vol. i. p. 30.
—— (90) Ueber Steinkohlenformation und Rothliegendes im Schwarzwald
und deren Flora. Jahrb. K.k. geol. Reichs. Bd. xl. Heft i. p. 77.
Sanio, K. (74) Anatomie der Gemeinen Kiefer (Pinus silvestris L.).
Pringsheim’s Jahrb. Bd. ix. p. 78.
Saporta, G. de. (62) Études sur la végétation du sud-est de la France à
l’époque Tertiaire. Ann. Sci. Nat. tome xvi. [4], p. 309.
—— (622) Ibid. tome xvii. p. 191.
—— (65) Ibid. tome iii. [5], p. 5.
—— (652) Ibid. tome iv. p. 5.
—— (68) Ibid. tome ix. p. 5.
—— (682) Note sur la flore fossile des regions arctiques. Bull. soc. géol.
France [2], tome xxv. p. 315.
—— (73) Études sur la végétation du sud-est de la France à l’époque
Tertiaire. Ann. Sci. nat. tome xvii. [5], p. 81.
—— (74) Sur la présence d’une Cycadée dans le dépôt Miocène de Koumi
(Eubée). Compt. Rend. vol. lxxviii. p. 1318.
—— (75) Sur la découverte de deux types nouveaux de Conifères dans les
schistes Permiens de Lodève (Hérault). Ibid. vol. lxxx. p. 1017.
—— (78) Observations sur la nature des végétaux réunis dans le groupe des
Noeggerathia; généralités et type du Noeggerathia foliosa Sternb. Ibid.
vol. lxxxvi. p. 746.
—— (782) Ibid. Types du Noeggerathia flabellata L. and H. et du N.
cyclopteroides Goepp. Ibid. vol. lxxxvi. p. 801.
—— (783) Ibid. Type des Noeggerathia expansa et cuneifolia de
Brongniart. Ibid. vol. lxxxvi. p. 860.
—— (784) Sur le nouveau groupe Paléozoique des Dolerophyllées. Ibid.
vol. lxxxvii. p. 393.
—— (82) Sur quelques types de végétaux récemment observés à l’état
fossile. Ibid. vol. xliv. p. 922.
—— (84) Paléontologie Française. Plantes Jurassiques, tome iii.
—— (91) Ibid. tome iv. Types Proangiospermiques.
Ann. Bot. vol. xxviii. p. 39.
Sanday, Elizabeth. (07) See Berridge and Sanday.
Sandberger, F. von. (64) Die Flora der oberen Steinkohlenformation im
badischer Schwarzwalde. Verh. Nat. Ver. Carlsruhe, vol. i. p. 30.
—— (90) Ueber Steinkohlenformation und Rothliegendes im Schwarzwald
und deren Flora. Jahrb. K.k. geol. Reichs. Bd. xl. Heft i. p. 77.
Sanio, K. (74) Anatomie der Gemeinen Kiefer (Pinus silvestris L.).
Pringsheim’s Jahrb. Bd. ix. p. 78.
Saporta, G. de. (62) Études sur la végétation du sud-est de la France à
l’époque Tertiaire. Ann. Sci. Nat. tome xvi. [4], p. 309.
—— (622) Ibid. tome xvii. p. 191.
—— (65) Ibid. tome iii. [5], p. 5.
—— (652) Ibid. tome iv. p. 5.
—— (68) Ibid. tome ix. p. 5.
—— (682) Note sur la flore fossile des regions arctiques. Bull. soc. géol.
France [2], tome xxv. p. 315.
—— (73) Études sur la végétation du sud-est de la France à l’époque
Tertiaire. Ann. Sci. nat. tome xvii. [5], p. 81.
—— (74) Sur la présence d’une Cycadée dans le dépôt Miocène de Koumi
(Eubée). Compt. Rend. vol. lxxviii. p. 1318.
—— (75) Sur la découverte de deux types nouveaux de Conifères dans les
schistes Permiens de Lodève (Hérault). Ibid. vol. lxxx. p. 1017.
—— (78) Observations sur la nature des végétaux réunis dans le groupe des
Noeggerathia; généralités et type du Noeggerathia foliosa Sternb. Ibid.
vol. lxxxvi. p. 746.
—— (782) Ibid. Types du Noeggerathia flabellata L. and H. et du N.
cyclopteroides Goepp. Ibid. vol. lxxxvi. p. 801.
—— (783) Ibid. Type des Noeggerathia expansa et cuneifolia de
Brongniart. Ibid. vol. lxxxvi. p. 860.
—— (784) Sur le nouveau groupe Paléozoique des Dolerophyllées. Ibid.
vol. lxxxvii. p. 393.
—— (82) Sur quelques types de végétaux récemment observés à l’état
fossile. Ibid. vol. xliv. p. 922.
—— (84) Paléontologie Française. Plantes Jurassiques, tome iii.
—— (91) Ibid. tome iv. Types Proangiospermiques.
Page 681
—— (93) Revue des travaux de Paléontologie végétale. Rev. Gén. tome v.
p. 1.
Saporta, G. de and A. F. Marion. (76) Recherches sur les végétaux
fossiles de Meximieux. Arch. Mus. d’hist. nat. de Lyon. Lyon.
—— (78) Révision de la flore Heersienne de Gelinden. Mém. cour. et Mém.
sav. étrang. tome xli. (Acad. roy. sci. etc. Belg.).
—— (85) L’Évolution du Règne végétal. Tome i. Les Phanérogames. Paris.
Saxton, W. T. (10) Contributions to the life-history of Widdringtonia
cupressoides. Bot. Gaz. vol. l. p. 31.
—— (102) Contributions to the life-history of Callitris. Ann. Bot. vol. xxiv.
p. 557.
—— (103) Notes on the anatomy of Widdringtonia and Callitris. S. African
Journ. Sci. p. 282.
—— (104) The development of the embryo of Encephalartos. Bot. Gaz. vol.
xlix. p. 13.
—— (12) Note on an abnormal prothallus of Pinus maritima L. Ann. Bot.
vol. xxvi. p. 943.
—— (13) Contributions to the life-history of Actinostrobus pyramidalis
Miq. Ann. Bot. vol. xxvii. p. 321.
—— (132) The classification of Conifers. New Phyt. vol. xii. p. 242.
—— (133) Contributions to the life-history of Tetraclinis articulata,
Masters, with some notes on the Phylogeny of the Cupressoideae and
the Callitroideae. Ann. Bot. vol. xxvii. p. 577.
Schauroth, C. von. (52) Herr von Schauroth an Herrn Beyrich. Zeit.
Deutsch. geol. Ges. Bd. iv. p. 538.
Schenk, A. (67) Ueber die Flora der schwarzen Schiefer von Raibl.
Würzburg. Naturwiss. Zeitsch. vol. vi. p. 10.
—— (68) Ueber die Pflanzenreste des Muschelkalkes von Recoaro.
Benecke’s Geog.-Pal. Beit. Bd. ii. München.
—— (682) Beiträge zur Flora der Vorwelt. Palaeontol. Bd. xvi. p. 218.
—— (71) Die fossilen Pflanzen der Wernsdorfer Schichten in der
Nordkarpathen. Ibid. Bd. xix. p. 1.
—— (80) Ueber fossile Hölzer aus der Libyschen Wüste. Bot. Zeit. Bd.
xxxviii. p. 657.
—— (82) Ueber Medullosa elegans. Engler’s Jahrb. Bd. iii. p. 156.
—— (822) Die von dem Gebrüdern Schagintweit in Indien gesammelten
fossilen Hölzer. Engler’s Bot. Jahrb. Bd. iii. p. 353.
p. 1.
Saporta, G. de and A. F. Marion. (76) Recherches sur les végétaux
fossiles de Meximieux. Arch. Mus. d’hist. nat. de Lyon. Lyon.
—— (78) Révision de la flore Heersienne de Gelinden. Mém. cour. et Mém.
sav. étrang. tome xli. (Acad. roy. sci. etc. Belg.).
—— (85) L’Évolution du Règne végétal. Tome i. Les Phanérogames. Paris.
Saxton, W. T. (10) Contributions to the life-history of Widdringtonia
cupressoides. Bot. Gaz. vol. l. p. 31.
—— (102) Contributions to the life-history of Callitris. Ann. Bot. vol. xxiv.
p. 557.
—— (103) Notes on the anatomy of Widdringtonia and Callitris. S. African
Journ. Sci. p. 282.
—— (104) The development of the embryo of Encephalartos. Bot. Gaz. vol.
xlix. p. 13.
—— (12) Note on an abnormal prothallus of Pinus maritima L. Ann. Bot.
vol. xxvi. p. 943.
—— (13) Contributions to the life-history of Actinostrobus pyramidalis
Miq. Ann. Bot. vol. xxvii. p. 321.
—— (132) The classification of Conifers. New Phyt. vol. xii. p. 242.
—— (133) Contributions to the life-history of Tetraclinis articulata,
Masters, with some notes on the Phylogeny of the Cupressoideae and
the Callitroideae. Ann. Bot. vol. xxvii. p. 577.
Schauroth, C. von. (52) Herr von Schauroth an Herrn Beyrich. Zeit.
Deutsch. geol. Ges. Bd. iv. p. 538.
Schenk, A. (67) Ueber die Flora der schwarzen Schiefer von Raibl.
Würzburg. Naturwiss. Zeitsch. vol. vi. p. 10.
—— (68) Ueber die Pflanzenreste des Muschelkalkes von Recoaro.
Benecke’s Geog.-Pal. Beit. Bd. ii. München.
—— (682) Beiträge zur Flora der Vorwelt. Palaeontol. Bd. xvi. p. 218.
—— (71) Die fossilen Pflanzen der Wernsdorfer Schichten in der
Nordkarpathen. Ibid. Bd. xix. p. 1.
—— (80) Ueber fossile Hölzer aus der Libyschen Wüste. Bot. Zeit. Bd.
xxxviii. p. 657.
—— (82) Ueber Medullosa elegans. Engler’s Jahrb. Bd. iii. p. 156.
—— (822) Die von dem Gebrüdern Schagintweit in Indien gesammelten
fossilen Hölzer. Engler’s Bot. Jahrb. Bd. iii. p. 353.
Page 682
—— (83) Fossile Hölzer der libyschen Wüste (Die Libysche Wüste, Bd.
iii.).
—— (89) Ueber Medullosa Cotta. Abh. K. Sächs. Ges. Wiss. Bd. xv. p. 523.
Schlechtendal, D. von. (02) Thuja occidentalis thuringiaca. Zeitsch.
Naturwiss. Stuttgart. Bd. lxxv. p. 33.
Schmalhausen, J. (83) Die Pflanzenreste der Steinkohlenformation am
östlichen Abhange des Ural Gebirges. Mém. Acad. S. Pétersbourg, vol.
xxxi. No. 13.
—— (832) Beiträge zur Tertiär Flora süd-west Russlands. Palaeontol. Abh.
(Dames and Kayser), Bd. i. Heft iv. p. 285.
—— (87) Die Pflanzenreste der Artinskischen und Permischen
Ablagerungen im Osten des Europäischen Russlands. Mém. Com. géol.
St Pétersbourg, vol. ii. No. iv. p. 1.
—— (90) Wissenschaftliche Resultate der von der Akad. der Wiss. zur
Erforschung des Janalandes und der Neusibirischen Inseln in den
Jahren 1885, 1886 ausgesandten Expedition. Abt. ii. Tertiäre Pflanzen
der Insel Neusibirien. Mém. l’acad. Imp. Sci. St Pétersbourg [vii], vol.
xxxvii. No. 5.
Schneider, W. (13) Vergleichend-morphologische Untersuchungen über die
Kurztriebe einiger Arten von Pinus. Flora [N.F.], Bd. v. p. 385.
Schroeter, C. (80) Untersuchung über fossile Hölzer aus der arctischen
Zone. (Heer’s Flor. Foss. Arct. vol. vi. 1882.)
—— (97) Ueber die Vielgestaltigkeit der Fichte (Picea excelsa Link.).
Vierteljahr. Naturforsch. Ges. Zürich. Jahrg. xlii. p. 125.
Schuster, J. (11) Ueber Goeppert’s Raumeria im Zwinger zu Dresden.
Sitzber. K. Bayer. Akad. Wiss. p. 489.
—— (112) Weltrichia und die Bennettitales. K. Svensk. Vetenskapsakad.
Hand. Bd. xlvi. No. 11.
—— (113) Pagiophyllum Weismanni im unteren Hauptmuschelkalk von
Würzburg. Geog. Jahresheft, Bd. xiii. p. 149.
—— (114) Bemerkungen über Podozamites. Ber. Deutsch. Bot. Ges. Bd.
xix. Heft 7, p. 450.
Schütze, E. (01) Beiträge zur Kenntniss der Triassischen Koniferen-
Gattungen Pagiophyllum, Voltzia, Widdringtonites. Jahresheft Ver. Vat.
Naturkunde, Stuttgart, p. 256.
Scott, D. H. (97) The anatomical characters presented by the peduncle of
Cycadaceae. Ann. Bot. vol. xi. p. 399.
iii.).
—— (89) Ueber Medullosa Cotta. Abh. K. Sächs. Ges. Wiss. Bd. xv. p. 523.
Schlechtendal, D. von. (02) Thuja occidentalis thuringiaca. Zeitsch.
Naturwiss. Stuttgart. Bd. lxxv. p. 33.
Schmalhausen, J. (83) Die Pflanzenreste der Steinkohlenformation am
östlichen Abhange des Ural Gebirges. Mém. Acad. S. Pétersbourg, vol.
xxxi. No. 13.
—— (832) Beiträge zur Tertiär Flora süd-west Russlands. Palaeontol. Abh.
(Dames and Kayser), Bd. i. Heft iv. p. 285.
—— (87) Die Pflanzenreste der Artinskischen und Permischen
Ablagerungen im Osten des Europäischen Russlands. Mém. Com. géol.
St Pétersbourg, vol. ii. No. iv. p. 1.
—— (90) Wissenschaftliche Resultate der von der Akad. der Wiss. zur
Erforschung des Janalandes und der Neusibirischen Inseln in den
Jahren 1885, 1886 ausgesandten Expedition. Abt. ii. Tertiäre Pflanzen
der Insel Neusibirien. Mém. l’acad. Imp. Sci. St Pétersbourg [vii], vol.
xxxvii. No. 5.
Schneider, W. (13) Vergleichend-morphologische Untersuchungen über die
Kurztriebe einiger Arten von Pinus. Flora [N.F.], Bd. v. p. 385.
Schroeter, C. (80) Untersuchung über fossile Hölzer aus der arctischen
Zone. (Heer’s Flor. Foss. Arct. vol. vi. 1882.)
—— (97) Ueber die Vielgestaltigkeit der Fichte (Picea excelsa Link.).
Vierteljahr. Naturforsch. Ges. Zürich. Jahrg. xlii. p. 125.
Schuster, J. (11) Ueber Goeppert’s Raumeria im Zwinger zu Dresden.
Sitzber. K. Bayer. Akad. Wiss. p. 489.
—— (112) Weltrichia und die Bennettitales. K. Svensk. Vetenskapsakad.
Hand. Bd. xlvi. No. 11.
—— (113) Pagiophyllum Weismanni im unteren Hauptmuschelkalk von
Würzburg. Geog. Jahresheft, Bd. xiii. p. 149.
—— (114) Bemerkungen über Podozamites. Ber. Deutsch. Bot. Ges. Bd.
xix. Heft 7, p. 450.
Schütze, E. (01) Beiträge zur Kenntniss der Triassischen Koniferen-
Gattungen Pagiophyllum, Voltzia, Widdringtonites. Jahresheft Ver. Vat.
Naturkunde, Stuttgart, p. 256.
Scott, D. H. (97) The anatomical characters presented by the peduncle of
Cycadaceae. Ann. Bot. vol. xi. p. 399.
Page 683
—— (99) On the structure and affinities of Fossil Plants from the
Palaeozoic rocks. III. On Medullosa anglica, a new representative of
the Cycadofilices. Phil. Trans. R. Soc. vol. cxci. p. 81.
—— (992) On the primary wood of certain Araucarioxylons. Ann. Bot. vol.
xiii. p. 615.
—— (02) On the Primary structure of certain Palaeozoic stems with the
Dadoxylon type of wood. Trans. R. Soc. vol. xl. p. 331.
—— (03) The origin of seed-bearing plants. R. Instit. Great Brit. Weekly
Evening meeting, Febry. 15.
—— (06) On Sutcliffia insignis, a new type of Medulloseae from the Lower
Coal Measures. Trans. Linn. Soc. vol. vii. pl. iv. p. 45.
—— (09) The Palaeontological Record. II. Plants. Darwin and Modern
Science, Art. xii. Cambridge.
—— (12) The structure of Mesoxylon Lomaxi and M. poroxyloides. Ann.
Bot. vol. xxvi. p. 1011.
—— (11) The Evolution of Plants. London.
—— (14) On Medullosa pusilla. Proc. R. Soc. vol. lxxxvii. p. 221.
—— (15) The Heterangiums of the British Coal Measures. British Assoc.
(Manchester Meeting 1915). (Abstract.)
Scott, D. H. and E. C. Jeffrey. (14) On Fossil Plants showing structure,
from the base of the Waverley shale of Kentucky. Phil. Trans. R. Soc.
vol. 205, p. 315.
Scott, D. H. and A. J. Maslen. (07) The structure of the Palaeozoic seeds
Trigonocarpus Parkinsoni Brongn. and T. Oliveri sp. nov. Ann. Bot.
vol. xxi. p. 89.
—— (10) On Mesoxylon, a new genus of Cordaitales. Ibid. vol. xxiv. p.
236.
Sellards, E. H. (03) Codonotheca, a new type of spore-bearing organ from
the Coal Measures. Amer. Journ. Sci. vol. xvi. p. 87.
—— (07) Notes on the spore-bearing organ Codonotheca and its
relationship with the Cycadofilices. New Phyt. vol. vi. p. 175.
Sernander, R. (93) Die Einwanderung der Fichte in Skandinavien. Engler’s
Bot. Jahrb. Bd. xv. p. 1.
Seward, A. C. (90) Tylodendron Weiss and Voltzia heterophylla Brong.
Geol. Mag. vol. vii. [3], p. 218.
—— (93) On the genus Myeloxylon. Ann. Bot. vol. xxv. p. 1.
Palaeozoic rocks. III. On Medullosa anglica, a new representative of
the Cycadofilices. Phil. Trans. R. Soc. vol. cxci. p. 81.
—— (992) On the primary wood of certain Araucarioxylons. Ann. Bot. vol.
xiii. p. 615.
—— (02) On the Primary structure of certain Palaeozoic stems with the
Dadoxylon type of wood. Trans. R. Soc. vol. xl. p. 331.
—— (03) The origin of seed-bearing plants. R. Instit. Great Brit. Weekly
Evening meeting, Febry. 15.
—— (06) On Sutcliffia insignis, a new type of Medulloseae from the Lower
Coal Measures. Trans. Linn. Soc. vol. vii. pl. iv. p. 45.
—— (09) The Palaeontological Record. II. Plants. Darwin and Modern
Science, Art. xii. Cambridge.
—— (12) The structure of Mesoxylon Lomaxi and M. poroxyloides. Ann.
Bot. vol. xxvi. p. 1011.
—— (11) The Evolution of Plants. London.
—— (14) On Medullosa pusilla. Proc. R. Soc. vol. lxxxvii. p. 221.
—— (15) The Heterangiums of the British Coal Measures. British Assoc.
(Manchester Meeting 1915). (Abstract.)
Scott, D. H. and E. C. Jeffrey. (14) On Fossil Plants showing structure,
from the base of the Waverley shale of Kentucky. Phil. Trans. R. Soc.
vol. 205, p. 315.
Scott, D. H. and A. J. Maslen. (07) The structure of the Palaeozoic seeds
Trigonocarpus Parkinsoni Brongn. and T. Oliveri sp. nov. Ann. Bot.
vol. xxi. p. 89.
—— (10) On Mesoxylon, a new genus of Cordaitales. Ibid. vol. xxiv. p.
236.
Sellards, E. H. (03) Codonotheca, a new type of spore-bearing organ from
the Coal Measures. Amer. Journ. Sci. vol. xvi. p. 87.
—— (07) Notes on the spore-bearing organ Codonotheca and its
relationship with the Cycadofilices. New Phyt. vol. vi. p. 175.
Sernander, R. (93) Die Einwanderung der Fichte in Skandinavien. Engler’s
Bot. Jahrb. Bd. xv. p. 1.
Seward, A. C. (90) Tylodendron Weiss and Voltzia heterophylla Brong.
Geol. Mag. vol. vii. [3], p. 218.
—— (93) On the genus Myeloxylon. Ann. Bot. vol. xxv. p. 1.
Page 684
—— (94) On Rachiopteris Williamsoni sp. nov., a new Fern from the Coal-
Measures. Ibid. vol. viii. p. 207.
—— (96) A new species of Conifer, Pinites Ruffordi, from the English
Wealden formation. Journ. Linn. Soc. vol. xxxii. p. 417.
—— (962) Notes on the geological history of Monocotyledons. Ann. Bot.
vol. x. p. 205.
—— (97) On Encephalartos Ghellinckii Lem., a rare Cycad. Proc. Camb.
Phil. Soc. vol. ix. p. 340.
—— (972) A contribution to our knowledge of Lyginodendron. Ann. Bot.
vol. xi. p. 65.
—— (973) On the association of Sigillaria and Glossopteris in S. Africa.
Quart. Journ. Geol. Soc. vol. liii. p. 315.
—— (974) On the leaves of Bennettites. Proc. Camb. Phil. Soc. vol. ix. p.
273.
—— (00) Notes on some Jurassic plants in the Manchester Museum. Mem.
Proc. Manchester Lit. Phil. Soc. vol. xliv. pt. iii. No. 8.
—— (03) On the occurrence of Dictyozamites in England, with Remarks on
European and Eastern Mesozoic Floras. Quart. Journ. Geol. Soc. vol.
lix. p. 217.
—— (06) Notes on Cycads. Proc. Camb. Phil. Soc. vol. xiii. pt. v. p. 299.
—— (07) Permo-Carboniferous plants from Kashmir. Rec. Geol. Surv.
India, vol. xxxvi. pt. i. p. 57.
—— (072) Jurassic plants from Caucasia and Turkestan. Mém. com. géol. St
Pétersbourg [N.S.], Livr. 38.
—— (10) Article “Gymnosperms,” Encyclop. Brit. edit. 11, vol. xii.
Cambridge.
—— (11) Jurassic plants from Chinese Dzungaria. Mém. com. geol. St
Pétersbourg [N.S.], Livr. 75.
—— (112) The Jurassic Flora of Sutherland. Trans. R. Soc. Edinb. vol. xlvii.
pt. iv. p. 643.
—— (113) Links with the Past in the Plant world. Cambridge.
—— (114) The Jurassic Flora of Yorkshire. The Naturalist, January, 1911.
—— (12) Mesozoic plants from Afghanistan and Afghan-Turkestan. Mem.
Geol. Surv. India, Pal. Ind. [N.S.], vol. iv. mem. No. 4.
—— (122) A petrified Williamsonia from Scotland. Phil. Trans. R. Soc. vol.
cciii. p. 101.
Measures. Ibid. vol. viii. p. 207.
—— (96) A new species of Conifer, Pinites Ruffordi, from the English
Wealden formation. Journ. Linn. Soc. vol. xxxii. p. 417.
—— (962) Notes on the geological history of Monocotyledons. Ann. Bot.
vol. x. p. 205.
—— (97) On Encephalartos Ghellinckii Lem., a rare Cycad. Proc. Camb.
Phil. Soc. vol. ix. p. 340.
—— (972) A contribution to our knowledge of Lyginodendron. Ann. Bot.
vol. xi. p. 65.
—— (973) On the association of Sigillaria and Glossopteris in S. Africa.
Quart. Journ. Geol. Soc. vol. liii. p. 315.
—— (974) On the leaves of Bennettites. Proc. Camb. Phil. Soc. vol. ix. p.
273.
—— (00) Notes on some Jurassic plants in the Manchester Museum. Mem.
Proc. Manchester Lit. Phil. Soc. vol. xliv. pt. iii. No. 8.
—— (03) On the occurrence of Dictyozamites in England, with Remarks on
European and Eastern Mesozoic Floras. Quart. Journ. Geol. Soc. vol.
lix. p. 217.
—— (06) Notes on Cycads. Proc. Camb. Phil. Soc. vol. xiii. pt. v. p. 299.
—— (07) Permo-Carboniferous plants from Kashmir. Rec. Geol. Surv.
India, vol. xxxvi. pt. i. p. 57.
—— (072) Jurassic plants from Caucasia and Turkestan. Mém. com. géol. St
Pétersbourg [N.S.], Livr. 38.
—— (10) Article “Gymnosperms,” Encyclop. Brit. edit. 11, vol. xii.
Cambridge.
—— (11) Jurassic plants from Chinese Dzungaria. Mém. com. geol. St
Pétersbourg [N.S.], Livr. 75.
—— (112) The Jurassic Flora of Sutherland. Trans. R. Soc. Edinb. vol. xlvii.
pt. iv. p. 643.
—— (113) Links with the Past in the Plant world. Cambridge.
—— (114) The Jurassic Flora of Yorkshire. The Naturalist, January, 1911.
—— (12) Mesozoic plants from Afghanistan and Afghan-Turkestan. Mem.
Geol. Surv. India, Pal. Ind. [N.S.], vol. iv. mem. No. 4.
—— (122) A petrified Williamsonia from Scotland. Phil. Trans. R. Soc. vol.
cciii. p. 101.
Page 685
—— (123) Jurassic plants from Amurland. Mém. com. geol. St Pétersbourg
[N.S.], Livr. 81.
—— (13) A contribution to our knowledge of Wealden Floras, with special
reference to a collection of plants from Sussex. Quart. Journ. Geol.
Soc. vol. lxix. p. 85.
—— (14) Antarctic Fossil plants. British Antarctic (Terra Nova) Expedit.
1910. Nat. Hist. Report, Geology, vol. i. No. 1. London.
—— (142) Wealden Floras. Hastings and East Sussex Naturalist, vol. ii. No.
3, p. 126.
Seward, A. C. and N. Bancroft. (13) Jurassic Plants from Cromarty and
Sutherland, Scotland. Trans. R. Soc. Edinb. vol. xlviii. pt. iv. p. 867.
Shaw, F. J. F. (08) A contribution to the anatomy of Ginkgo biloba. New
Phyt. vol. vii. p. 85.
—— (09) The seedling structure of Araucaria Bidwillii. Ann. Bot. vol. xxiii.
p. 321.
Shaw, W. R. (96) Contribution to the life-history of Sequoia sempervirens.
Bot. Gaz. vol. xxi. p. 332.
Shirley, J. (98) Additions to the Fossil Flora of Queensland Geol. Surv.
Bull. No. 7. Brisbane.
Siebold, P. F. von. (70) Flora Japonica, 1842–70. Leipzig.
Sifton, H. B. (15) On the occurrence and significance of “bars” or “rims” of
Sanio in the Cycads. Bot. Gaz. vol. lx. p. 400.
Sigrianski, A. (13) Quelques observations sur l’Ephedra helvetica Mey.
Univ. Genève. Faculté des sciences, Prof. Chodat [8], Fasc. x.
Sinnott, E. W. (09) Paracedroxylon, a new type of Araucarian wood.
Rhodora, vol. ii. No. 129, p. 165.
—— (11) Some features of the anatomy of the foliar bundle. Bot. Gaz. vol.
li. p. 258.
—— (13) The morphology of the reproductive structures in the
Podocarpineae. Ann. Bot. vol. xxvii. p. 39.
Smith, F. G. (07) Morphology of the trunk and development of the
microsporangium of Cycads. Bot. Gaz. vol. xliii. p. 187.
Smith, J. E. (1797) Characters of a new genus of plants named Salisburia.
Trans. Linn. Soc. vol. iii. p. 330.
Solereder, H. (99) Systematische Anatomie der Dicotyledonen. Stuttgart.
—— (08) Ibid. Ergänzungaband.
[N.S.], Livr. 81.
—— (13) A contribution to our knowledge of Wealden Floras, with special
reference to a collection of plants from Sussex. Quart. Journ. Geol.
Soc. vol. lxix. p. 85.
—— (14) Antarctic Fossil plants. British Antarctic (Terra Nova) Expedit.
1910. Nat. Hist. Report, Geology, vol. i. No. 1. London.
—— (142) Wealden Floras. Hastings and East Sussex Naturalist, vol. ii. No.
3, p. 126.
Seward, A. C. and N. Bancroft. (13) Jurassic Plants from Cromarty and
Sutherland, Scotland. Trans. R. Soc. Edinb. vol. xlviii. pt. iv. p. 867.
Shaw, F. J. F. (08) A contribution to the anatomy of Ginkgo biloba. New
Phyt. vol. vii. p. 85.
—— (09) The seedling structure of Araucaria Bidwillii. Ann. Bot. vol. xxiii.
p. 321.
Shaw, W. R. (96) Contribution to the life-history of Sequoia sempervirens.
Bot. Gaz. vol. xxi. p. 332.
Shirley, J. (98) Additions to the Fossil Flora of Queensland Geol. Surv.
Bull. No. 7. Brisbane.
Siebold, P. F. von. (70) Flora Japonica, 1842–70. Leipzig.
Sifton, H. B. (15) On the occurrence and significance of “bars” or “rims” of
Sanio in the Cycads. Bot. Gaz. vol. lx. p. 400.
Sigrianski, A. (13) Quelques observations sur l’Ephedra helvetica Mey.
Univ. Genève. Faculté des sciences, Prof. Chodat [8], Fasc. x.
Sinnott, E. W. (09) Paracedroxylon, a new type of Araucarian wood.
Rhodora, vol. ii. No. 129, p. 165.
—— (11) Some features of the anatomy of the foliar bundle. Bot. Gaz. vol.
li. p. 258.
—— (13) The morphology of the reproductive structures in the
Podocarpineae. Ann. Bot. vol. xxvii. p. 39.
Smith, F. G. (07) Morphology of the trunk and development of the
microsporangium of Cycads. Bot. Gaz. vol. xliii. p. 187.
Smith, J. E. (1797) Characters of a new genus of plants named Salisburia.
Trans. Linn. Soc. vol. iii. p. 330.
Solereder, H. (99) Systematische Anatomie der Dicotyledonen. Stuttgart.
—— (08) Ibid. Ergänzungaband.
Page 686
Solms-Laubach, Graf zu. (84) Die Coniferenformen des Deutschen
Kupferschiefers und Zechsteins. Pal. Abhand. (Dames and Kayser),
Bd. ii. Heft ii. p. 81.
—— (90) Die Sprossfolge der Stangeria und der übrigen Cycadeen. Bot.
Zeit. Jahrg. xlviii.
—— (91) On the Fructification of Bennettites Gibsonianus Carr. Ann. Bot.
vol. v. p. 419.
—— (92) See Capellini and Solms-Laubach.
—— (93) Ueber die in den Kalksteinen des Kulm von Glätzisch-Falkenberg
in Schlesien enthaltenen Structur bietenden Pflanzenreste. Bot. Zeit.
Jahrg. li. p. 197.
—— (97) Ueber Medullosa Leuckarti. Ibid. Heft x. p. 175.
—— (99) Das Auftreten und die Flora der rhätischen Kohlenschichten von
La Ternera (Chili). Neues Jahrb. Min. Beilage, Bd. xii. p. 581.
—— (04) Die strukturbietenden Pflanzengesteine von Franz Josefs Land.
K. Svensk. Vetenskapsakad. Hand. Bd. xxxvii. No. 7, p. 3.
—— (06) Die Bedeutung der Palaeophytologie für die systematische
Botanik. Mitt. Philomath. Ges. in Elsass-Lothringen, Bd. iii. p. 353.
—— (10) Über die in den Kalksteinen des Culm von Glätzisch-Falkenberg
in Schlesien erhaltenen structurbietenden Pflanzenreste. IV. Völkelia
refracta, Steloxylon Ludwigii. Zeitsch. Bot. Jahrg. ii. Heft viii. p. 529.
South, F. W. and R. H. Compton. (08) Notes on the anatomy of Dioon
edule Lind. New Phyt. vol. vii. p. 222.
Spiess, Karl von. (02) Ginkgo, Cephalotaxus, und die Taxaceen. Eine
phylogenetische Studie. Öster. Bot. Zeitsch. Jahrg. lii. p. 432.
—— (03) Ibid. Jahrg. liii. p. 1.
Sprecher, A. (07) Le Ginkgo biloba L. Genève.
Squinabol, S. (92) Contribuzioni alla flora fossile dei terreni terziarii della
Liguria. Gênes, 1889–92.
Stapf, O. (89) Die Arten der Gattung Ephedra. Denksch. K. Akad. Wiss.
Wien, Bd. lvi.
—— (96) On the Flora of Mount Kinabalu in North Borneo. Trans. Linn.
Soc. [2], vol. iv. p. 69.
—— (14) Encephalartos Hildebrandtii. Bull. Miscell. Information, R. Bot.
Gard. Kew, No. 10, p. 386.
Starr, Anna M. (10) The microsporophylls of Ginkgo. Bot. Gaz. vol. xlix.
p. 51.
Kupferschiefers und Zechsteins. Pal. Abhand. (Dames and Kayser),
Bd. ii. Heft ii. p. 81.
—— (90) Die Sprossfolge der Stangeria und der übrigen Cycadeen. Bot.
Zeit. Jahrg. xlviii.
—— (91) On the Fructification of Bennettites Gibsonianus Carr. Ann. Bot.
vol. v. p. 419.
—— (92) See Capellini and Solms-Laubach.
—— (93) Ueber die in den Kalksteinen des Kulm von Glätzisch-Falkenberg
in Schlesien enthaltenen Structur bietenden Pflanzenreste. Bot. Zeit.
Jahrg. li. p. 197.
—— (97) Ueber Medullosa Leuckarti. Ibid. Heft x. p. 175.
—— (99) Das Auftreten und die Flora der rhätischen Kohlenschichten von
La Ternera (Chili). Neues Jahrb. Min. Beilage, Bd. xii. p. 581.
—— (04) Die strukturbietenden Pflanzengesteine von Franz Josefs Land.
K. Svensk. Vetenskapsakad. Hand. Bd. xxxvii. No. 7, p. 3.
—— (06) Die Bedeutung der Palaeophytologie für die systematische
Botanik. Mitt. Philomath. Ges. in Elsass-Lothringen, Bd. iii. p. 353.
—— (10) Über die in den Kalksteinen des Culm von Glätzisch-Falkenberg
in Schlesien erhaltenen structurbietenden Pflanzenreste. IV. Völkelia
refracta, Steloxylon Ludwigii. Zeitsch. Bot. Jahrg. ii. Heft viii. p. 529.
South, F. W. and R. H. Compton. (08) Notes on the anatomy of Dioon
edule Lind. New Phyt. vol. vii. p. 222.
Spiess, Karl von. (02) Ginkgo, Cephalotaxus, und die Taxaceen. Eine
phylogenetische Studie. Öster. Bot. Zeitsch. Jahrg. lii. p. 432.
—— (03) Ibid. Jahrg. liii. p. 1.
Sprecher, A. (07) Le Ginkgo biloba L. Genève.
Squinabol, S. (92) Contribuzioni alla flora fossile dei terreni terziarii della
Liguria. Gênes, 1889–92.
Stapf, O. (89) Die Arten der Gattung Ephedra. Denksch. K. Akad. Wiss.
Wien, Bd. lvi.
—— (96) On the Flora of Mount Kinabalu in North Borneo. Trans. Linn.
Soc. [2], vol. iv. p. 69.
—— (14) Encephalartos Hildebrandtii. Bull. Miscell. Information, R. Bot.
Gard. Kew, No. 10, p. 386.
Starr, Anna M. (10) The microsporophylls of Ginkgo. Bot. Gaz. vol. xlix.
p. 51.
Page 687
Staub, M. (85) Pinus palaeostrobus Etting. in der fossilen Flora Ungarns.
Természetrajzi Füzetek, ix. p. 47.
—— (96) Die Fossilen Ctenis-Arten und Ctenis hungarica n. sp. Földtani
Közlöny, vol. xxvi.
Stefani, C. de. (01) Flore Carbonifere e Permiane della Toscana. R. Inst.
Stud. sup. pratici e di perfezionamento in Firenze.
Stenzel, G. (76) Beobachtungen an durchwachsenden Fichtenzapfen. Nov.
Act. Leop. Carol. Bd. xxxviii.
—— (88) See Goeppert and Stenzel.
Sterzel; J. T. (83) Ueber Dicksonia Pluckeneti (Schloth.). Bot. Cent. Bd.
xiii. p. 282.
—— (00) Gruppe verkieselter Araucariten Stämme. Bericht Naturwiss.
Ges. Chemnitz, Bd. xiv.
—— (03) Ein verkieselter Riesenbaum aus dem Rothliegenden von
Chemnitz. Ibid. Bd. xv. p. 23.
—— (07) Die Karbon- und Rotliegendfloren im Grossherzogtum Baden.
Mitt. Badisch. geol. Landes. Bd. v. Heft ii. p. 347.
—— (12) Der “verkieselte Wald” im Garten des König Albert Museums
und des Orth-Denkmal in Chemnitz-Hilbersdorf. Bericht Naturwiss.
Ges. Chemnitz, Bd. xviii. p. 51.
Stiles, W. (08) The anatomy of Saxegothaea conspicua Lind. New Phyt.
vol. vii. p. 209.
—— (12) The Podocarpeae. Ann. Bot. vol. xxvi. p. 443.
Stirling, J. (00) Notes on the Fossil Flora of South Gippsland Jurassic beds.
Rep. on the Vict. coal-fields, No. 7. (Dpt. Mines, Victoria.)
Stokes and Webb. (24) Descriptions of some fossil vegetables of the
Tilgate Forest in Sussex. Trans. Geol. Soc. [2], vol. ii. p. 421.
Stopes, Marie C. (03) On the leaf of Cordaites. New Phyt. vol. ii. p. 91.
—— (04) Beiträge zur Kenntniss der Fortpflanzungsorgane der Cycadeen.
Flora, Bd. xciii. Heft iv. p. 435.
—— (05) On the double nature of the Cycadean integument. Ann. Bot. vol.
xix. p. 561.
—— (07) The Flora of the Inferior Oolite of Brora (Sutherland). Quart.
Journ. Geol. Soc. vol. lxiii. p. 375.
—— (10) Adventitious budding and branching in Cycas. New Phyt. vol. ix.
p. 235.
Természetrajzi Füzetek, ix. p. 47.
—— (96) Die Fossilen Ctenis-Arten und Ctenis hungarica n. sp. Földtani
Közlöny, vol. xxvi.
Stefani, C. de. (01) Flore Carbonifere e Permiane della Toscana. R. Inst.
Stud. sup. pratici e di perfezionamento in Firenze.
Stenzel, G. (76) Beobachtungen an durchwachsenden Fichtenzapfen. Nov.
Act. Leop. Carol. Bd. xxxviii.
—— (88) See Goeppert and Stenzel.
Sterzel; J. T. (83) Ueber Dicksonia Pluckeneti (Schloth.). Bot. Cent. Bd.
xiii. p. 282.
—— (00) Gruppe verkieselter Araucariten Stämme. Bericht Naturwiss.
Ges. Chemnitz, Bd. xiv.
—— (03) Ein verkieselter Riesenbaum aus dem Rothliegenden von
Chemnitz. Ibid. Bd. xv. p. 23.
—— (07) Die Karbon- und Rotliegendfloren im Grossherzogtum Baden.
Mitt. Badisch. geol. Landes. Bd. v. Heft ii. p. 347.
—— (12) Der “verkieselte Wald” im Garten des König Albert Museums
und des Orth-Denkmal in Chemnitz-Hilbersdorf. Bericht Naturwiss.
Ges. Chemnitz, Bd. xviii. p. 51.
Stiles, W. (08) The anatomy of Saxegothaea conspicua Lind. New Phyt.
vol. vii. p. 209.
—— (12) The Podocarpeae. Ann. Bot. vol. xxvi. p. 443.
Stirling, J. (00) Notes on the Fossil Flora of South Gippsland Jurassic beds.
Rep. on the Vict. coal-fields, No. 7. (Dpt. Mines, Victoria.)
Stokes and Webb. (24) Descriptions of some fossil vegetables of the
Tilgate Forest in Sussex. Trans. Geol. Soc. [2], vol. ii. p. 421.
Stopes, Marie C. (03) On the leaf of Cordaites. New Phyt. vol. ii. p. 91.
—— (04) Beiträge zur Kenntniss der Fortpflanzungsorgane der Cycadeen.
Flora, Bd. xciii. Heft iv. p. 435.
—— (05) On the double nature of the Cycadean integument. Ann. Bot. vol.
xix. p. 561.
—— (07) The Flora of the Inferior Oolite of Brora (Sutherland). Quart.
Journ. Geol. Soc. vol. lxiii. p. 375.
—— (10) Adventitious budding and branching in Cycas. New Phyt. vol. ix.
p. 235.
Page 688
—— (102) The internal anatomy of Nilssonia orientalis. Ann. Bot. vol. xxiv.
p. 389.
—— (11) The Dragon tree of the Kentish Rag, with remarks on the
treatment of imperfectly petrified wood. Geol. Mag. [5], vol. viii. p. 55.
—— (112) The name of the Dragon tree. Ibid. p. 468.
—— (11³) A reply to Prof. Jeffrey’s article on Yezonia and Cryptomeriopsis.
Ann. Bot. vol. xxv. p. 269.
—— (114) On the true nature of the Cretaceous plant Ophioglossum
granulatum Hr. Ann. Bot. vol. xxv. p. 903.
—— (14) The “Fern Ledges” Carboniferous Flora of St John, New
Brunswick. Dpt. Mines, Geol. Surv., Canada, Mem. 41, No. 38, Geol.
Ser. Ottawa.
—— (142) A new Araucarioxylon from New Zealand. Ann. Bot. vol. xxviii.
p. 341.
—— (15) Catalogue of the Mesozoic Plants in the British Museum (Nat.
Hist.). The Cretaceous Flora. Pt. ii. Lower Greensand (Aptian) plants
of Britain. London.
—— (16) An early type of the Abietineae(?) from the Cretaceous of New
Zealand. Ann. Bot. vol. xxx. p. 111.
Stopes, M. C. and K. Fujii. (10) Studies on the structure and affinities of
Cretaceous Plants. Phil. Trans. R. Soc. vol. cci. p. 1.
Stopes, M. C. and E. M. Kershaw. (10) The anatomy of Cretaceous Pine
leaves. Ann. Bot. vol. xxiv. p. 395.
Stopes, M. C. and D. M. S. Watson. (08) The present distribution and
origin of the calcareous concretions in coal-seams known as “coal-
balls.” Phil. Trans. R. Soc. vol. cc. p. 167.
Strasburger, E. (66) Ein Beitrag zur Entwickelungsgeschichte der
Spaltöffnungen. Pringsheim’s Jahrb. Bd. v. p. 297.
—— (91) Ueber den Bau und die Verrichtungen der Leitungsbahnen in den
Pflanzen. Histol. Beit. Heft iii. Jena.
Strübing, O. (88) Die Vertheilung der Spaltöffnungen bei den Coniferen.
(Inaug. Diss. Univ. Königsberg.)
Stur, D. (68) Beiträge zur Kenntniss der geologischen Verhältnisse der
Umgegend von Raibl und Kaltwasser. Jahrb. K.k. geol. Reichs. Wien,
Bd. xviii. p. 71.
—— (77) Die Culm Flora. Heft ii. Wien.
p. 389.
—— (11) The Dragon tree of the Kentish Rag, with remarks on the
treatment of imperfectly petrified wood. Geol. Mag. [5], vol. viii. p. 55.
—— (112) The name of the Dragon tree. Ibid. p. 468.
—— (11³) A reply to Prof. Jeffrey’s article on Yezonia and Cryptomeriopsis.
Ann. Bot. vol. xxv. p. 269.
—— (114) On the true nature of the Cretaceous plant Ophioglossum
granulatum Hr. Ann. Bot. vol. xxv. p. 903.
—— (14) The “Fern Ledges” Carboniferous Flora of St John, New
Brunswick. Dpt. Mines, Geol. Surv., Canada, Mem. 41, No. 38, Geol.
Ser. Ottawa.
—— (142) A new Araucarioxylon from New Zealand. Ann. Bot. vol. xxviii.
p. 341.
—— (15) Catalogue of the Mesozoic Plants in the British Museum (Nat.
Hist.). The Cretaceous Flora. Pt. ii. Lower Greensand (Aptian) plants
of Britain. London.
—— (16) An early type of the Abietineae(?) from the Cretaceous of New
Zealand. Ann. Bot. vol. xxx. p. 111.
Stopes, M. C. and K. Fujii. (10) Studies on the structure and affinities of
Cretaceous Plants. Phil. Trans. R. Soc. vol. cci. p. 1.
Stopes, M. C. and E. M. Kershaw. (10) The anatomy of Cretaceous Pine
leaves. Ann. Bot. vol. xxiv. p. 395.
Stopes, M. C. and D. M. S. Watson. (08) The present distribution and
origin of the calcareous concretions in coal-seams known as “coal-
balls.” Phil. Trans. R. Soc. vol. cc. p. 167.
Strasburger, E. (66) Ein Beitrag zur Entwickelungsgeschichte der
Spaltöffnungen. Pringsheim’s Jahrb. Bd. v. p. 297.
—— (91) Ueber den Bau und die Verrichtungen der Leitungsbahnen in den
Pflanzen. Histol. Beit. Heft iii. Jena.
Strübing, O. (88) Die Vertheilung der Spaltöffnungen bei den Coniferen.
(Inaug. Diss. Univ. Königsberg.)
Stur, D. (68) Beiträge zur Kenntniss der geologischen Verhältnisse der
Umgegend von Raibl und Kaltwasser. Jahrb. K.k. geol. Reichs. Wien,
Bd. xviii. p. 71.
—— (77) Die Culm Flora. Heft ii. Wien.
Page 689
Suzuki, Y. (10) On the structure and affinities of two new Conifers and a
new fungus from the Upper Cretaceous of Hokkaido (Yezo). Bot. Mag.
Tokyo, vol. xxiv. No. 284, p. 183.
Sykes, M. G. (10) (See also Thoday, M. G.) The anatomy of Welwitschia
mirabilis Hook. f. in the seedling and adult stages. Trans. Linn. Soc.
vol. vii. pt. ii. p. 327.
—— (102) The anatomy and morphology of the leaves and inflorescences
of Welwitschia mirabilis. Phil. Trans. R. Soc. vol. cci. p. 179.
Takeda, H. (13) A theory of transfusion-tissue. Ann. Bot. vol. xxvii. p. 359.
—— (132) Some points in the anatomy of the leaf of Welwitschia mirabilis.
Ibid. vol. xxvii. p. 347.
Tate, R. (67). On the secondary fossils from S. Africa. Quart. Journ. Geol.
Soc. vol. xxiii. p. 130.
Tenison Woods, J. E. (83) On a species of Brachyphyllum from Mesozoic
coal beds, Ipswich, Queensland. Proc. Linn. Soc. N.S.W. vol. vii. p.
659.
Thibout, E. (96) Recherches sur l’appareil mâle des Gymnospermes. Lille.
Thiselton-Dyer, W. T. (72) On some Coniferous remains from the
Lithographic stone of Solenhofen. Geol. Mag. vol. ix. p. 1.
—— (01) The carpophyll of Encephalartos. Ann. Bot. vol. xv. p. 548.
—— (012) Persistence of the leaf-traces in Araucaria. Ibid. vol. xv. p. 547.
—— (02) Enumeration of the plants known from China proper, Formosa,
etc. Cycadaceae. Journ. Linn. Soc. vol. xxvi. p. 559.
Thoday, Mary G. (Sykes, M. G.). (11) The female inflorescence and
ovules of Gnetum africanum, with notes on G. secundum. Ann. Bot.
vol. xxv. p. 1101.
Thoday, M. G. and Emily M. Berridge. (12) The anatomy and
morphology of the Inflorescences and flowers of Ephedra. Ann. Bot.
vol. xxvi. p. 953.
Thomas, F. (66) Zur vergleichenden Anatomie der Coniferen-Laubblätter.
Pringsheim’s Jahrb. Bd. iv. p. 23.
Thomas, H. Hamshaw. (11) The Jurassic Flora of Kamenka in the district
of Isium. Mém. com. géol. St. Pétersbourg [N.S.], Livr. 71.
—— (12) Note on the occurrence of Whittleseya elegans Newb. in Britain.
Palaeobot. Zeitsch. Bd. i. Heft i. p. 46.
—— (13) On some new and rare Jurassic plants from Yorkshire:
Eretmophyllum, a new type of Ginkgoalean leaf. Proc. Camb. Phil.
new fungus from the Upper Cretaceous of Hokkaido (Yezo). Bot. Mag.
Tokyo, vol. xxiv. No. 284, p. 183.
Sykes, M. G. (10) (See also Thoday, M. G.) The anatomy of Welwitschia
mirabilis Hook. f. in the seedling and adult stages. Trans. Linn. Soc.
vol. vii. pt. ii. p. 327.
—— (102) The anatomy and morphology of the leaves and inflorescences
of Welwitschia mirabilis. Phil. Trans. R. Soc. vol. cci. p. 179.
Takeda, H. (13) A theory of transfusion-tissue. Ann. Bot. vol. xxvii. p. 359.
—— (132) Some points in the anatomy of the leaf of Welwitschia mirabilis.
Ibid. vol. xxvii. p. 347.
Tate, R. (67). On the secondary fossils from S. Africa. Quart. Journ. Geol.
Soc. vol. xxiii. p. 130.
Tenison Woods, J. E. (83) On a species of Brachyphyllum from Mesozoic
coal beds, Ipswich, Queensland. Proc. Linn. Soc. N.S.W. vol. vii. p.
659.
Thibout, E. (96) Recherches sur l’appareil mâle des Gymnospermes. Lille.
Thiselton-Dyer, W. T. (72) On some Coniferous remains from the
Lithographic stone of Solenhofen. Geol. Mag. vol. ix. p. 1.
—— (01) The carpophyll of Encephalartos. Ann. Bot. vol. xv. p. 548.
—— (012) Persistence of the leaf-traces in Araucaria. Ibid. vol. xv. p. 547.
—— (02) Enumeration of the plants known from China proper, Formosa,
etc. Cycadaceae. Journ. Linn. Soc. vol. xxvi. p. 559.
Thoday, Mary G. (Sykes, M. G.). (11) The female inflorescence and
ovules of Gnetum africanum, with notes on G. secundum. Ann. Bot.
vol. xxv. p. 1101.
Thoday, M. G. and Emily M. Berridge. (12) The anatomy and
morphology of the Inflorescences and flowers of Ephedra. Ann. Bot.
vol. xxvi. p. 953.
Thomas, F. (66) Zur vergleichenden Anatomie der Coniferen-Laubblätter.
Pringsheim’s Jahrb. Bd. iv. p. 23.
Thomas, H. Hamshaw. (11) The Jurassic Flora of Kamenka in the district
of Isium. Mém. com. géol. St. Pétersbourg [N.S.], Livr. 71.
—— (12) Note on the occurrence of Whittleseya elegans Newb. in Britain.
Palaeobot. Zeitsch. Bd. i. Heft i. p. 46.
—— (13) On some new and rare Jurassic plants from Yorkshire:
Eretmophyllum, a new type of Ginkgoalean leaf. Proc. Camb. Phil.
Page 690
Soc. vol. xvii. pt. iii. p. 256.
—— (132) The Fossil Flora of the Cleveland district of Yorkshire. I. The
Flora of the Marske quarry. Quart. Journ. Geol. Soc. vol. lxix. p. 223.
—— (15) On some new and rare Jurassic plants from Yorkshire: The male
flower of Williamsonia gigas. Proc. Camb. Phil. Soc. vol. xviii. pt. iii.
p. 105.
—— (152) On Williamsoniella, a New Type of Bennettitalean Flower. Phil.
Trans. R. Soc. vol. 207, p. 113.
Thomas, H. H. and Nellie Bancroft. (13) On the cuticles of some recent
and fossil Cycadean fronds. Trans. Linn. Soc. vol. viii. pt. v. p. 155.
Thompson, W. P. (10) The origin of ray-tracheids in the Coniferae. Bot.
Gaz. vol. l. p. 101.
—— (12) Ray-tracheids in Abies. Ibid. vol. liii. p. 53.
—— (122) The anatomy and relationship of the Gnetales. I. The genus
Ephedra. Ann. Bot. vol. xxvi. p. 1077.
—— (12³) The structure of the stomata of certain Cretaceous Conifers. Bot.
Gaz. vol. liv. p. 63.
—— (16) The Morphology and Affinities of Gnetum. Amer. Journ. Bot. vol
iii. p. 135.
Thomson, R. B. (07) The Araucarineae, a Protosiphonogamic method of
Fertilisation. Science [N.S.], vol. xxv. p. 272.
—— (09) On the pollen of Microcachrys tetragona. Bot. Gaz. vol. xlvii. p.
26.
—— (13) On the comparative anatomy and affinities of the Araucarineae.
Phil. Trans. R. Soc. vol. cciv. p. 1.
—— (14) The spur-shoot of the Pines. Bot. Gaz. vol. lvii. p. 362.
Thomson, R. B. and A. E. Allin. (12) Do the Abietineae extend to the
Carboniferous? Bot. Gaz. vol. liii. p. 339.
Tison, A. (09) Sur le Saxegothaea conspicua Lind. Mém. soc. Linn.
Normand. vol. xxiii. p. 139.
—— (12) Sur la persistance de la nervation dichotomique chez les
Conifères. Bull. soc. Linn. Normandie [vi], vol. iv. p. 30.
—— (122) See Lignier and Tison.
Tupper, W. W. (11) Notes on Ginkgo biloba. Bot. Gaz. vol. li. p. 374.
Tuzson, J. (09) Monographie der fossilen Pflanzenreste der
Balatonseegegend. Result. der Wiss. Erforsch. des Balatonsees, Bd. i.
Teil i. Budapest.
—— (132) The Fossil Flora of the Cleveland district of Yorkshire. I. The
Flora of the Marske quarry. Quart. Journ. Geol. Soc. vol. lxix. p. 223.
—— (15) On some new and rare Jurassic plants from Yorkshire: The male
flower of Williamsonia gigas. Proc. Camb. Phil. Soc. vol. xviii. pt. iii.
p. 105.
—— (152) On Williamsoniella, a New Type of Bennettitalean Flower. Phil.
Trans. R. Soc. vol. 207, p. 113.
Thomas, H. H. and Nellie Bancroft. (13) On the cuticles of some recent
and fossil Cycadean fronds. Trans. Linn. Soc. vol. viii. pt. v. p. 155.
Thompson, W. P. (10) The origin of ray-tracheids in the Coniferae. Bot.
Gaz. vol. l. p. 101.
—— (12) Ray-tracheids in Abies. Ibid. vol. liii. p. 53.
—— (122) The anatomy and relationship of the Gnetales. I. The genus
Ephedra. Ann. Bot. vol. xxvi. p. 1077.
—— (12³) The structure of the stomata of certain Cretaceous Conifers. Bot.
Gaz. vol. liv. p. 63.
—— (16) The Morphology and Affinities of Gnetum. Amer. Journ. Bot. vol
iii. p. 135.
Thomson, R. B. (07) The Araucarineae, a Protosiphonogamic method of
Fertilisation. Science [N.S.], vol. xxv. p. 272.
—— (09) On the pollen of Microcachrys tetragona. Bot. Gaz. vol. xlvii. p.
26.
—— (13) On the comparative anatomy and affinities of the Araucarineae.
Phil. Trans. R. Soc. vol. cciv. p. 1.
—— (14) The spur-shoot of the Pines. Bot. Gaz. vol. lvii. p. 362.
Thomson, R. B. and A. E. Allin. (12) Do the Abietineae extend to the
Carboniferous? Bot. Gaz. vol. liii. p. 339.
Tison, A. (09) Sur le Saxegothaea conspicua Lind. Mém. soc. Linn.
Normand. vol. xxiii. p. 139.
—— (12) Sur la persistance de la nervation dichotomique chez les
Conifères. Bull. soc. Linn. Normandie [vi], vol. iv. p. 30.
—— (122) See Lignier and Tison.
Tupper, W. W. (11) Notes on Ginkgo biloba. Bot. Gaz. vol. li. p. 374.
Tuzson, J. (09) Monographie der fossilen Pflanzenreste der
Balatonseegegend. Result. der Wiss. Erforsch. des Balatonsees, Bd. i.
Teil i. Budapest.
Page 691
—— (092) Beiträge zur fossilen Flora Ungarns. Mitt. Jahrb. K. Ung. Geol.
Reichs. Bd. xxi. Heft viii. p. 233.
—— (14) Beiträge zur fossilen Flora Ungarns. Mitt. Jahrb. K. Ungarisch.
Geol. Reichs. Bd. xxi. Heft viii.
Unger, F. (45) Synopsis Plantarum Fossilium. Leipzig.
—— (47) Chloris Protogaea. Leipzig.
—— (49) Einige interessante Pflanzenabdrücke aus der K.
Petrefactensammlung in München. Bot. Zeit. p. 345.
—— (51) Die Fossile Flora von Sotzka. Denksch. K. Akad. Wiss. Wien, Bd.
ii. Abt. ii. p. 131.
—— (52) Ueber einige fossile Pflanzen aus den lithographischen Schiefer
von Solenhofen. Palaeontograph. Bd. ii. p. 251.
—— (522) Iconographia plantarum fossilium. Abbildungen und
Beschreibungen fossiler Pflanzen. Denksch. K. Akad. Wiss. Wien, Bd.
iv. p. 73.
—— (54) Zur Flora des Cypridinenschiefers. Sitzber. K. Akad. Wiss. Wien,
Bd. xii. p. 595.
—— (542) Jurassische Pflanzenreste. Palaeontograph. Bd. iv. p. 39.
—— (59) Der versteinerte Wald bei Cairo. Sitzber. K. Akad. Wiss. Wien, Bd.
xxxiii. p. 209.
—— (67) Die fossile Flora von Kumi. Denksch. K. Akad. Wiss. Wien, Bd.
xxvii. p. 27.
Veitch’s Manual of the Conifers. (00) London.
Velenovský, J. (81) Die Flora aus den Ausgebrannten Tertiären Letten von
Vršovic bei Laun. Abh. böhm. Ges. [vi], Bd. ii.
—— (87) Neue Beiträge zur Kenntniss der Pflanzen des böhmischen
Cenomans. Sitzber. K. böhm. Ges. Wiss. Jahrg. 1886, p. 633.
—— (88) Ueber einige neue Pflanzenformen der böhmischen
Kreideformation. Ibid. Jahrg. 1887.
—— (89) Květena Českého Cenomanu. Abh. K. böhm. Ges. Wiss. [vii], Bd.
iii.
—— (07) Vergleichende Morphologie der Pflanzen. Teil ii. Prag.
Vernon, R. D. (12) On the geology and palaeontology of the Warwickshire
coalfield. Quart. Journ. Geol. Soc. vol. lxviii. p. 587.
Vetters, K. L. (84) Die Blattstiele der Cycadeen. (Inaug. Diss.) Leipzig.
Vierhapper, F. (10) Entwurf eines neuen Systems der Coniferen. Jena.
Reichs. Bd. xxi. Heft viii. p. 233.
—— (14) Beiträge zur fossilen Flora Ungarns. Mitt. Jahrb. K. Ungarisch.
Geol. Reichs. Bd. xxi. Heft viii.
Unger, F. (45) Synopsis Plantarum Fossilium. Leipzig.
—— (47) Chloris Protogaea. Leipzig.
—— (49) Einige interessante Pflanzenabdrücke aus der K.
Petrefactensammlung in München. Bot. Zeit. p. 345.
—— (51) Die Fossile Flora von Sotzka. Denksch. K. Akad. Wiss. Wien, Bd.
ii. Abt. ii. p. 131.
—— (52) Ueber einige fossile Pflanzen aus den lithographischen Schiefer
von Solenhofen. Palaeontograph. Bd. ii. p. 251.
—— (522) Iconographia plantarum fossilium. Abbildungen und
Beschreibungen fossiler Pflanzen. Denksch. K. Akad. Wiss. Wien, Bd.
iv. p. 73.
—— (54) Zur Flora des Cypridinenschiefers. Sitzber. K. Akad. Wiss. Wien,
Bd. xii. p. 595.
—— (542) Jurassische Pflanzenreste. Palaeontograph. Bd. iv. p. 39.
—— (59) Der versteinerte Wald bei Cairo. Sitzber. K. Akad. Wiss. Wien, Bd.
xxxiii. p. 209.
—— (67) Die fossile Flora von Kumi. Denksch. K. Akad. Wiss. Wien, Bd.
xxvii. p. 27.
Veitch’s Manual of the Conifers. (00) London.
Velenovský, J. (81) Die Flora aus den Ausgebrannten Tertiären Letten von
Vršovic bei Laun. Abh. böhm. Ges. [vi], Bd. ii.
—— (87) Neue Beiträge zur Kenntniss der Pflanzen des böhmischen
Cenomans. Sitzber. K. böhm. Ges. Wiss. Jahrg. 1886, p. 633.
—— (88) Ueber einige neue Pflanzenformen der böhmischen
Kreideformation. Ibid. Jahrg. 1887.
—— (89) Květena Českého Cenomanu. Abh. K. böhm. Ges. Wiss. [vii], Bd.
iii.
—— (07) Vergleichende Morphologie der Pflanzen. Teil ii. Prag.
Vernon, R. D. (12) On the geology and palaeontology of the Warwickshire
coalfield. Quart. Journ. Geol. Soc. vol. lxviii. p. 587.
Vetters, K. L. (84) Die Blattstiele der Cycadeen. (Inaug. Diss.) Leipzig.
Vierhapper, F. (10) Entwurf eines neuen Systems der Coniferen. Jena.
Page 692
Ward, L. F. (85) Synopsis of the Laramie group. 6th Ann. Rep. U. S. Geol.
Surv.
—— (87) Types of the Laramie Flora. Bull. U. S. Geol. Surv. xxxvii.
—— (88) The geographical distribution of Fossil Plants. 8th Ann. Rep. U.
S. Geol. Surv. (1887–88).
—— (94) Fossil Cycadean trunks of North America, with a revision of the
genus Cycadeoidea Buckland. Proc. Biol. Soc. Washington, vol. ix. p.
75.
—— (942) Recent discoveries of Cycadean trunks in the Potomac formation
of Maryland. Bull. Torrey Bot. Club, vol. xxi. No. vii. p. 291.
—— (94³) The Cretaceous Rim of the Black Hills. Journ. Geol. vol. ii. No.
iii. p. 250.
—— (96) Some analogies in the Lower Cretaceous of Europe and America.
16th Ann. Rep. U. S. Geol. Surv.
—— (98) Descriptions of the species of Cycadeoidea or fossil Cycadean
trunks thus far determined from the Lower Cretaceous rim of the Black
Hills. Proc. U. S. Nat. Mus. vol. xxi. p. 21.
—— (00) Elaboration of the Fossil Cycads in the Yale Museum. Amer.
Journ. Sci. vol. x. p. 327.
—— (002) Description of a new genus and 20 new species of fossil
Cycadean trunks from the Jurassic of Wyoming. Proc. Washington
Acad. Sci. vol. i. p. 253.
—— (00³) Report on the petrified forests of Arizona. Depart. of the
Interior, Washington.
—— (04) A famous fossil Cycad. Amer. Journ. Sci. vol. xviii. p. 40.
Warming, E. (77) Recherches et remarques sur les Cycadées. Oversigt K.
D. Vidensk. Selsk. Forh. (Copenhagen), p. 16.
Warren, E. (12) On some specimens of fossil woods in the Natal Museum.
Ann. Natal Mus. vol. ii. pt. iii. p. 345.
Webber, H. J. (01) Spermatogenesis and fecundation of Zamia. U. S. Dpt.
Agric. Bur. Plant Industry, Bull. No. ii.
Weiss, C. E. (72) Fossile Flora der jüngsten Steinkohlen-formation und des
Rothliegenden im Saar-Rhein-Gebiet. Bonn, 1869–72.
—— (74) Note in Zeitsch. Deutsch. Geol. Ges. Bd. xxvi. p. 616.
—— (79) Die Flora des Rothliegenden von Wünschendorf bei Lauban in
Schlesien. Abh. geol. Specialkarte von Preussen Bd. iii. Heft i. p. 1.
Surv.
—— (87) Types of the Laramie Flora. Bull. U. S. Geol. Surv. xxxvii.
—— (88) The geographical distribution of Fossil Plants. 8th Ann. Rep. U.
S. Geol. Surv. (1887–88).
—— (94) Fossil Cycadean trunks of North America, with a revision of the
genus Cycadeoidea Buckland. Proc. Biol. Soc. Washington, vol. ix. p.
75.
—— (942) Recent discoveries of Cycadean trunks in the Potomac formation
of Maryland. Bull. Torrey Bot. Club, vol. xxi. No. vii. p. 291.
—— (94³) The Cretaceous Rim of the Black Hills. Journ. Geol. vol. ii. No.
iii. p. 250.
—— (96) Some analogies in the Lower Cretaceous of Europe and America.
16th Ann. Rep. U. S. Geol. Surv.
—— (98) Descriptions of the species of Cycadeoidea or fossil Cycadean
trunks thus far determined from the Lower Cretaceous rim of the Black
Hills. Proc. U. S. Nat. Mus. vol. xxi. p. 21.
—— (00) Elaboration of the Fossil Cycads in the Yale Museum. Amer.
Journ. Sci. vol. x. p. 327.
—— (002) Description of a new genus and 20 new species of fossil
Cycadean trunks from the Jurassic of Wyoming. Proc. Washington
Acad. Sci. vol. i. p. 253.
—— (00³) Report on the petrified forests of Arizona. Depart. of the
Interior, Washington.
—— (04) A famous fossil Cycad. Amer. Journ. Sci. vol. xviii. p. 40.
Warming, E. (77) Recherches et remarques sur les Cycadées. Oversigt K.
D. Vidensk. Selsk. Forh. (Copenhagen), p. 16.
Warren, E. (12) On some specimens of fossil woods in the Natal Museum.
Ann. Natal Mus. vol. ii. pt. iii. p. 345.
Webber, H. J. (01) Spermatogenesis and fecundation of Zamia. U. S. Dpt.
Agric. Bur. Plant Industry, Bull. No. ii.
Weiss, C. E. (72) Fossile Flora der jüngsten Steinkohlen-formation und des
Rothliegenden im Saar-Rhein-Gebiet. Bonn, 1869–72.
—— (74) Note in Zeitsch. Deutsch. Geol. Ges. Bd. xxvi. p. 616.
—— (79) Die Flora des Rothliegenden von Wünschendorf bei Lauban in
Schlesien. Abh. geol. Specialkarte von Preussen Bd. iii. Heft i. p. 1.
Page 693
Weiss, F. E. (12) Report of the 80th meeting (Portsmouth) of the British
Assoc. for the Advancement of Science, p. 550.
—— (13) The root-apex and young root of Lyginodendron. Mem. Proc.
Manchester Lit. Phil. Soc. vol. lvii. pt. iii.
—— (132) A Tylodendron-like fossil. Ibid. vol. lvii. pt. iii.
Wernham, H. F. (11) Floral Evolution; with particular reference to the
sympetalous Dicotyledons. New Phyt. vol. x. p. 73.
Wettstein, R. V. (90) Die Omorika-Fichte, Picea omorica (Panc.). Sitzber.
K. Akad. Wiss. Wien, Bd. xcviii. Abt. i. p. 503.
—— (11) Handbuch der systematischen Botanik. (Edit. ii.) Leipzig.
Wherry, E. T. (12) Silicified wood from the Triassic of Pennsylvania. Proc.
Acad. Sci. Philadelphia, vol. lxiv. pt. ii. p. 366.
White, D. (90) On Cretaceous Plants from Martha’s Vineyard. Amer. Journ.
Sci. vol. xxxix. p. 93.
—— (01) The Canadian species of the genus Whittleseya and the
systematic relations. The Ottawa Naturalist, vol. xv. No. iv. p. 98.
White, D. and C. Schuchert. (98) Cretaceous series of the West coast of
Greenland. Bull. Geol. Soc. America, vol. ix. p. 343.
Wieland, G. R. (99) A study of some American Fossil Cycads. Pt. ii. The
Leaf structure of Cycadeoidea. Amer. Journ. Sci. vol. vii. p. 305.
—— (02) Notes on living Cycads. I. On the Zamias of Florida. Ibid. vol.
xiii. p. 331.
—— (06) American Fossil Cycads. Washington.
—— (08) Historic Fossil Cycads. Amer. Journ. Sci. vol. xxv. p. 93.
—— (082) Two new Araucarias from the Western Cretaceous. Geol. Surv.
South Dakota.
—— (09) The Williamsonias of the Mixteca Alta. Bot. Gaz. vol. xlviii. p.
427.
—— (11) On the Williamsonia Tribe. Amer. Journ. Sci. vol. xxxii. p. 433.
—— (112) A study of some American Fossil Cycads. Pt. v. Ibid. vol. xxxii.
p. 133.
—— (12) Ibid. pt. vi. On the smaller flower-buds of Cycadeoidea. Ibid. vol.
xxxiii. p. 73.
—— (13) The Liassic Flora of the Mixteca Alta of Mexico, its composition,
age, and source. Ibid. vol. xxxvi. p. 251.
—— (14) A study of some American Fossil Cycads. Pt. vii. Further notes
on disk structure. Ibid. vol. xxxviii. p. 117.
Assoc. for the Advancement of Science, p. 550.
—— (13) The root-apex and young root of Lyginodendron. Mem. Proc.
Manchester Lit. Phil. Soc. vol. lvii. pt. iii.
—— (132) A Tylodendron-like fossil. Ibid. vol. lvii. pt. iii.
Wernham, H. F. (11) Floral Evolution; with particular reference to the
sympetalous Dicotyledons. New Phyt. vol. x. p. 73.
Wettstein, R. V. (90) Die Omorika-Fichte, Picea omorica (Panc.). Sitzber.
K. Akad. Wiss. Wien, Bd. xcviii. Abt. i. p. 503.
—— (11) Handbuch der systematischen Botanik. (Edit. ii.) Leipzig.
Wherry, E. T. (12) Silicified wood from the Triassic of Pennsylvania. Proc.
Acad. Sci. Philadelphia, vol. lxiv. pt. ii. p. 366.
White, D. (90) On Cretaceous Plants from Martha’s Vineyard. Amer. Journ.
Sci. vol. xxxix. p. 93.
—— (01) The Canadian species of the genus Whittleseya and the
systematic relations. The Ottawa Naturalist, vol. xv. No. iv. p. 98.
White, D. and C. Schuchert. (98) Cretaceous series of the West coast of
Greenland. Bull. Geol. Soc. America, vol. ix. p. 343.
Wieland, G. R. (99) A study of some American Fossil Cycads. Pt. ii. The
Leaf structure of Cycadeoidea. Amer. Journ. Sci. vol. vii. p. 305.
—— (02) Notes on living Cycads. I. On the Zamias of Florida. Ibid. vol.
xiii. p. 331.
—— (06) American Fossil Cycads. Washington.
—— (08) Historic Fossil Cycads. Amer. Journ. Sci. vol. xxv. p. 93.
—— (082) Two new Araucarias from the Western Cretaceous. Geol. Surv.
South Dakota.
—— (09) The Williamsonias of the Mixteca Alta. Bot. Gaz. vol. xlviii. p.
427.
—— (11) On the Williamsonia Tribe. Amer. Journ. Sci. vol. xxxii. p. 433.
—— (112) A study of some American Fossil Cycads. Pt. v. Ibid. vol. xxxii.
p. 133.
—— (12) Ibid. pt. vi. On the smaller flower-buds of Cycadeoidea. Ibid. vol.
xxxiii. p. 73.
—— (13) The Liassic Flora of the Mixteca Alta of Mexico, its composition,
age, and source. Ibid. vol. xxxvi. p. 251.
—— (14) A study of some American Fossil Cycads. Pt. vii. Further notes
on disk structure. Ibid. vol. xxxviii. p. 117.
Page 694
—— (16) American Fossil Cycads. Vol. ii. Taxonomy. Washington.
Wiesner, J. (03) Die Rohstoffe des Pflanzenreiches. Bd. ii. Leipzig.
Wild, G. (00) On new and interesting features in Trigonocarpus
olivaeformis. Trans. Manchester Geol. Soc. vol. xxvi. pt. xv. p. 434.
Williamson, W. C. (40) On the Distribution of Fossil remains on the
Yorkshire coast from the Lower Lias to the Bath Oolite inclusive.
Trans. Geol. Soc. [2], vol. v. p. 223.
—— (51) On the structure and affinities of the plants known as
Sternbergiae. Manchester Lit. Phil. Soc. [2], vol. ix. p. 340.
—— (69) On the structure and affinities of some exogens from the Coal
Measures. Monthly Micros. Journ. vol. ii. p. 66.
—— (70) Contributions towards the history of Zamia gigas L. and H.
Trans. Linn. Soc. vol. xxvi. p. 663.
—— (72) Notice of further researches among the plants of the Coal
Measures. Proc. R. Soc. vol. xx. p. 435.
—— (722) On the structure of the Dicotyledons of the Coal Measures. Rep.
41st meeting (Edinburgh) of the Brit. Assoc. p. 111.
—— (74) On the Organisation of the Fossil Plants of the Coal Measures.
VI. Phil. Trans. R. Soc. vol. clxii. p. 675.
—— (76) On some fossil seeds from the Lower Carboniferous beds of
Lancashire. Rep. 45th meeting (Bristol) of the Brit. Assoc. p. 159.
—— (86) On the morphology of Pinites oblongus. Mem. Proc. Manchester
Lit. Phil. Soc. vol. x. [3], p. 189.
—— (87) On the Organisation of the Fossil Plants of the Coal Measures.
XIII. Phil. Trans. R. Soc. vol. 178.
—— (90) Ibid. XVII. Ibid. vol. clxxxi. p. 89.
Wiliamson, W. C. and D. H. Scott. (94) The root of Lyginodendron
oldhamium Will. Proc. R. Soc. vol. lvi. p. 128.
—— (95) Further observations on the Organisation of the Fossil Plants of
the Coal Measures. III. Lyginodendron and Heterangium. Phil. Trans.
R. Soc. vol. clxxxvi. p. 703.
Wills, Lucy. (14) Plant cuticles from the Coal Measures. Geol. Mag. [6], vol.
i. p. 385.
Wills, L. T. (10) The fossiliferous Lower Keuper rocks of Worcestershire.
Proc. Geol. Assoc. vol. xxi. p. 249.
Winkler, C. (72) Zur Anatomie von Araucaria brasiliensis. Bot. Zeit. Jahrg.
xxx. p. 581.
Wiesner, J. (03) Die Rohstoffe des Pflanzenreiches. Bd. ii. Leipzig.
Wild, G. (00) On new and interesting features in Trigonocarpus
olivaeformis. Trans. Manchester Geol. Soc. vol. xxvi. pt. xv. p. 434.
Williamson, W. C. (40) On the Distribution of Fossil remains on the
Yorkshire coast from the Lower Lias to the Bath Oolite inclusive.
Trans. Geol. Soc. [2], vol. v. p. 223.
—— (51) On the structure and affinities of the plants known as
Sternbergiae. Manchester Lit. Phil. Soc. [2], vol. ix. p. 340.
—— (69) On the structure and affinities of some exogens from the Coal
Measures. Monthly Micros. Journ. vol. ii. p. 66.
—— (70) Contributions towards the history of Zamia gigas L. and H.
Trans. Linn. Soc. vol. xxvi. p. 663.
—— (72) Notice of further researches among the plants of the Coal
Measures. Proc. R. Soc. vol. xx. p. 435.
—— (722) On the structure of the Dicotyledons of the Coal Measures. Rep.
41st meeting (Edinburgh) of the Brit. Assoc. p. 111.
—— (74) On the Organisation of the Fossil Plants of the Coal Measures.
VI. Phil. Trans. R. Soc. vol. clxii. p. 675.
—— (76) On some fossil seeds from the Lower Carboniferous beds of
Lancashire. Rep. 45th meeting (Bristol) of the Brit. Assoc. p. 159.
—— (86) On the morphology of Pinites oblongus. Mem. Proc. Manchester
Lit. Phil. Soc. vol. x. [3], p. 189.
—— (87) On the Organisation of the Fossil Plants of the Coal Measures.
XIII. Phil. Trans. R. Soc. vol. 178.
—— (90) Ibid. XVII. Ibid. vol. clxxxi. p. 89.
Wiliamson, W. C. and D. H. Scott. (94) The root of Lyginodendron
oldhamium Will. Proc. R. Soc. vol. lvi. p. 128.
—— (95) Further observations on the Organisation of the Fossil Plants of
the Coal Measures. III. Lyginodendron and Heterangium. Phil. Trans.
R. Soc. vol. clxxxvi. p. 703.
Wills, Lucy. (14) Plant cuticles from the Coal Measures. Geol. Mag. [6], vol.
i. p. 385.
Wills, L. T. (10) The fossiliferous Lower Keuper rocks of Worcestershire.
Proc. Geol. Assoc. vol. xxi. p. 249.
Winkler, C. (72) Zur Anatomie von Araucaria brasiliensis. Bot. Zeit. Jahrg.
xxx. p. 581.
Page 695
Witham, H. (30) On the vegetable fossils from Lennel Braes near
Coldstream, upon the banks of the Tweed in Berwickshire. Phil. Mag.
vol. viii. p. 16.
—— (31) Observations on fossil vegetables accompanied by
representations of their internal structure as seen through the
microscope. Edinb. Journ. Sci. vol. v. p. 183.
Worsdell, W. C. (96) The anatomy of the stem of Macrozamia compared
with that of other genera of Cycadeae. Ann. Bot. vol. x. p. 601.
—— (97) On transfusion-tissue, its origin and function in the leaves of
Gymnospermous plants. Trans. Linn. Soc. vol. v. [2], p. 301.
—— (98) The vascular structure of the sporophylls of the Cycadaceae. Ann.
Bot. vol. xii. p. 203.
—— (982) The comparative anatomy of certain genera of the Cycadaceae.
Journ. Linn. Soc. vol. xxxiii. p. 437.
—— (99) Observations on the vascular system of the female flowers of
Conifers. Ann. Bot. vol. xiii. p. 527.
—— (00) The comparative anatomy of certain species of Encephalartos.
Trans. Linn. Soc. vol. v. pt. xiv. p. 445.
—— (002) The affinities of the Mesozoic fossil Bennettites Gibsonianus
Carr. Ann. Bot. vol. xiv. p. 717.
—— (01) Contributions to the comparative anatomy of the Cycadaceae.
Trans. Linn. Soc. vol. vi. pt. ii. p. 109.
—— (012) The vascular structure of the flowers of the Gnetaceae. Ann. Bot.
vol. xv. p. 766.
—— (04) The structure and morphology of the ovule. Ann. Bot. vol. xviii.
p. 57.
—— (05) Fasciation, its meaning and origin. New Phyt. vol. iv. p. 55.
—— (06) The structure and origin of the Cycadaceae. Ann. Bot. vol. xx. p.
129.
Wright, W. B. (14) The Quaternary Ice Age. London.
Yabe, H. (13) Mesozoische Pflanzen von Omoto. Sci. Rep. of the Tokoku
Imp. Univ. (ser. ii. Geol.), Bd. i. Heft iv. p. 57.
Yates, J. (55) Notice of Zamia gigas. Proc. Yorks. Phil. Soc. vol. i. p. 37.
Yokoyama, M. (94) Mesozoic plants from Kozuke, Kii, Awa, and Tosa.
Journ. Coll. Sci. Imp. Univ. Japan, vol. vii. pt. iii. p. 201.
—— (05) Mesozoic plants from Nagato and Bitchu. Ibid. vol. xx.
Young, J. (69) Trans. Nat. Hist. Soc. Glasgow, vol. i. pl. iv. (No text.)
Coldstream, upon the banks of the Tweed in Berwickshire. Phil. Mag.
vol. viii. p. 16.
—— (31) Observations on fossil vegetables accompanied by
representations of their internal structure as seen through the
microscope. Edinb. Journ. Sci. vol. v. p. 183.
Worsdell, W. C. (96) The anatomy of the stem of Macrozamia compared
with that of other genera of Cycadeae. Ann. Bot. vol. x. p. 601.
—— (97) On transfusion-tissue, its origin and function in the leaves of
Gymnospermous plants. Trans. Linn. Soc. vol. v. [2], p. 301.
—— (98) The vascular structure of the sporophylls of the Cycadaceae. Ann.
Bot. vol. xii. p. 203.
—— (982) The comparative anatomy of certain genera of the Cycadaceae.
Journ. Linn. Soc. vol. xxxiii. p. 437.
—— (99) Observations on the vascular system of the female flowers of
Conifers. Ann. Bot. vol. xiii. p. 527.
—— (00) The comparative anatomy of certain species of Encephalartos.
Trans. Linn. Soc. vol. v. pt. xiv. p. 445.
—— (002) The affinities of the Mesozoic fossil Bennettites Gibsonianus
Carr. Ann. Bot. vol. xiv. p. 717.
—— (01) Contributions to the comparative anatomy of the Cycadaceae.
Trans. Linn. Soc. vol. vi. pt. ii. p. 109.
—— (012) The vascular structure of the flowers of the Gnetaceae. Ann. Bot.
vol. xv. p. 766.
—— (04) The structure and morphology of the ovule. Ann. Bot. vol. xviii.
p. 57.
—— (05) Fasciation, its meaning and origin. New Phyt. vol. iv. p. 55.
—— (06) The structure and origin of the Cycadaceae. Ann. Bot. vol. xx. p.
129.
Wright, W. B. (14) The Quaternary Ice Age. London.
Yabe, H. (13) Mesozoische Pflanzen von Omoto. Sci. Rep. of the Tokoku
Imp. Univ. (ser. ii. Geol.), Bd. i. Heft iv. p. 57.
Yates, J. (55) Notice of Zamia gigas. Proc. Yorks. Phil. Soc. vol. i. p. 37.
Yokoyama, M. (94) Mesozoic plants from Kozuke, Kii, Awa, and Tosa.
Journ. Coll. Sci. Imp. Univ. Japan, vol. vii. pt. iii. p. 201.
—— (05) Mesozoic plants from Nagato and Bitchu. Ibid. vol. xx.
Young, J. (69) Trans. Nat. Hist. Soc. Glasgow, vol. i. pl. iv. (No text.)
Page 696
—— (76) Catalogue of the Western Scottish fossils. Glasgow.
Young, Mary S. (07) The male gametophyte of Dacrydium. Bot. Gaz. vol.
xliv. p. 189.
—— (10) The morphology of the Podocarpineae. Ibid. vol. l. p. 81.
Zalessky, M. (05) Über Früchte aus den Untercarbon-Ablagerungen des
Mstabeckens in Nord Russland. Bull. acad. Imp. sci. St. Pétersbourg,
tome xxii. No. iii. p. 113.
—— (052) Notiz über die obercarbonische Flora des Steinkohlenreviers von
Jantai in der südlichen Mandshurei. Verhand. K. Russ. Min. Ges. St.
Pétersbourg [2], Bd. xlii. p. 385.
—— (09) Communication préliminaire sur un nouveau Dadoxylon
provenant du Dévonien supérieur du bassin du Donetz. Bull. acad.
Imp. sci. St. Pétersbourg.
—— (10) On the discovery of the calcareous concretions known as coal
balls in one of the seams of the Carboniferous strata of the Donetz
basin. Ibid. p. 477.
—— (11) Étude sur l’anatomie du Dadoxylon Tchihatcheffi Goepp. sp.
Mém. com. géol. St. Pétersb. [N.S.], Livr. 68, p. 1.
—— (112) Note préliminaire sur le Coenoxylon Scotti, nov. gen. et sp.
Études Paléobotaniques, pt. i. St. Petersburg.
—— (12) Sur le Cordaites aequalis Goepp. sp. de Sibérie et sur son identité
avec la Noeggerathiopsis Hislopi Bunb. sp. de la Flore du Gondwana.
Mém. com. géol. St. Pétersb. [N.S.], Livr. 86.
—— (122) On the impressions of plants from the coal-bearing deposits of
Sudženka, Siberia. Bull. soc. Natural. Orel. pt. iv.
—— (13) Flore Gondwanienne du Bassin de la Pétchora. I. Rivière Adzva.
Bull. soc. Oural. d’amis des Sci. Nat. à Ekatérinebourg, vol. xxxiii.
Zang, W. (04) Die Anatomie der Kiefernadel und ihre Verwendung zur
systematischen Gliederung der Gattung Pinus. (Diss. Inaug.) Giessen.
Zeiller, R. (78) Sur une nouvelle espèce de Dicranophyllum. Bull. soc.
géol. France [3], vol. vi. p. 611.
—— (80) Note sur quelques plantes fossiles du terrain permien de la
Corrèze. Ibid. vol. viii. [3], p. 196.
—— (96) Le Marquis G. de Saporta, sa vie et ses travaux. Bull. soc. géol.
France [3], vol. xxiv. p. 197.
—— (00) Sur les végétaux fossiles recueillis par M. Villiaume dans les
gîtes charbonneux du Nord-ouest de Madagascar. Compt. Rend. Jun. 5.
Young, Mary S. (07) The male gametophyte of Dacrydium. Bot. Gaz. vol.
xliv. p. 189.
—— (10) The morphology of the Podocarpineae. Ibid. vol. l. p. 81.
Zalessky, M. (05) Über Früchte aus den Untercarbon-Ablagerungen des
Mstabeckens in Nord Russland. Bull. acad. Imp. sci. St. Pétersbourg,
tome xxii. No. iii. p. 113.
—— (052) Notiz über die obercarbonische Flora des Steinkohlenreviers von
Jantai in der südlichen Mandshurei. Verhand. K. Russ. Min. Ges. St.
Pétersbourg [2], Bd. xlii. p. 385.
—— (09) Communication préliminaire sur un nouveau Dadoxylon
provenant du Dévonien supérieur du bassin du Donetz. Bull. acad.
Imp. sci. St. Pétersbourg.
—— (10) On the discovery of the calcareous concretions known as coal
balls in one of the seams of the Carboniferous strata of the Donetz
basin. Ibid. p. 477.
—— (11) Étude sur l’anatomie du Dadoxylon Tchihatcheffi Goepp. sp.
Mém. com. géol. St. Pétersb. [N.S.], Livr. 68, p. 1.
—— (112) Note préliminaire sur le Coenoxylon Scotti, nov. gen. et sp.
Études Paléobotaniques, pt. i. St. Petersburg.
—— (12) Sur le Cordaites aequalis Goepp. sp. de Sibérie et sur son identité
avec la Noeggerathiopsis Hislopi Bunb. sp. de la Flore du Gondwana.
Mém. com. géol. St. Pétersb. [N.S.], Livr. 86.
—— (122) On the impressions of plants from the coal-bearing deposits of
Sudženka, Siberia. Bull. soc. Natural. Orel. pt. iv.
—— (13) Flore Gondwanienne du Bassin de la Pétchora. I. Rivière Adzva.
Bull. soc. Oural. d’amis des Sci. Nat. à Ekatérinebourg, vol. xxxiii.
Zang, W. (04) Die Anatomie der Kiefernadel und ihre Verwendung zur
systematischen Gliederung der Gattung Pinus. (Diss. Inaug.) Giessen.
Zeiller, R. (78) Sur une nouvelle espèce de Dicranophyllum. Bull. soc.
géol. France [3], vol. vi. p. 611.
—— (80) Note sur quelques plantes fossiles du terrain permien de la
Corrèze. Ibid. vol. viii. [3], p. 196.
—— (96) Le Marquis G. de Saporta, sa vie et ses travaux. Bull. soc. géol.
France [3], vol. xxiv. p. 197.
—— (00) Sur les végétaux fossiles recueillis par M. Villiaume dans les
gîtes charbonneux du Nord-ouest de Madagascar. Compt. Rend. Jun. 5.
Page 697
—— (02) Nouvelles observations sur la flore fossile du bassin de
Kousnetzk (Sibérie). Ibid. tome cxxxiv. p. 887.
—— (05) Sur les plantes Rhétiennes de la Perse recueillies par M. J. de
Morgan. Bull. soc. géol. France [4], tome v. p. 190.
—— (052) Sur quelques empreintes végétales de la formation charbonneuse
supracrétacée des Balkans. Ann. Mines.
—— (08) See Douvillé and Zeiller.
—— (11) Note sur quelques végétaux infraliasiques des environs de Niort.
Bull. soc. géol. France [4], tome xi. p. 321.
—— (112) Sur une flore triasique découverte à Madagascar. Compt. Rend.
vol. cliii. p. 230.
—— (12) Sur quelques végétaux fossiles de la Grande Oolite de Marquise.
Bull. soc. acad. Boulogne-sur-mer, tome ix. p. 5.
—— (N.D.) See Malloizel and Zeiller.
Zeiller, R. and P. Fliche. (04) Découverte de strobiles de Sequoia et de Pin
dans le Portlandien des environs de Boulogne-sur-mer. Compt. Rend.
tome cxxxvii. p. 1020.
Zeiller, R. and L. M. Vidal. (02) Sobre algunas impresiones vegetales del
Kimeridgense de Santa María de Meyá. Mem. Real Acad. Cienc. y
Artes Barcelona, vol. iv. No. 26.
Zigno, A. de. (53) Découverte d’une flore Jurassique analogue à celle de
Scarborough dans les couches oolitiques des Alpes Vénitiennes. Bull.
soc. géol. France [2], vol. x. p. 268.
—— (73–85) Flora fossilis formationis Oolithicae. Vol. ii. Padua, 1873–85.
Zopf, W. (92) Ueber einige niedere Algenpilze (Phycomyceten) und eine
neue Methode ihre Keime aus dem Wasser zu isoliren. Abh.
Naturforsch. Ges. Halle, Bd. xvii. p. 79.
ERRATUM For Elwes, H. J. and A. Henry (60)
read (06)
Kousnetzk (Sibérie). Ibid. tome cxxxiv. p. 887.
—— (05) Sur les plantes Rhétiennes de la Perse recueillies par M. J. de
Morgan. Bull. soc. géol. France [4], tome v. p. 190.
—— (052) Sur quelques empreintes végétales de la formation charbonneuse
supracrétacée des Balkans. Ann. Mines.
—— (08) See Douvillé and Zeiller.
—— (11) Note sur quelques végétaux infraliasiques des environs de Niort.
Bull. soc. géol. France [4], tome xi. p. 321.
—— (112) Sur une flore triasique découverte à Madagascar. Compt. Rend.
vol. cliii. p. 230.
—— (12) Sur quelques végétaux fossiles de la Grande Oolite de Marquise.
Bull. soc. acad. Boulogne-sur-mer, tome ix. p. 5.
—— (N.D.) See Malloizel and Zeiller.
Zeiller, R. and P. Fliche. (04) Découverte de strobiles de Sequoia et de Pin
dans le Portlandien des environs de Boulogne-sur-mer. Compt. Rend.
tome cxxxvii. p. 1020.
Zeiller, R. and L. M. Vidal. (02) Sobre algunas impresiones vegetales del
Kimeridgense de Santa María de Meyá. Mem. Real Acad. Cienc. y
Artes Barcelona, vol. iv. No. 26.
Zigno, A. de. (53) Découverte d’une flore Jurassique analogue à celle de
Scarborough dans les couches oolitiques des Alpes Vénitiennes. Bull.
soc. géol. France [2], vol. x. p. 268.
—— (73–85) Flora fossilis formationis Oolithicae. Vol. ii. Padua, 1873–85.
Zopf, W. (92) Ueber einige niedere Algenpilze (Phycomyceten) und eine
neue Methode ihre Keime aus dem Wasser zu isoliren. Abh.
Naturforsch. Ges. Halle, Bd. xvii. p. 79.
ERRATUM For Elwes, H. J. and A. Henry (60)
read (06)
Page 698
INDEX
Abies magnifica 75
Acanthocarpus 305
A. xanthioides 305
Acrostichum crinitum 568
Adiantides 173
Adiantites 173
A. bellidulus 173, 174, 307
Aetheotesta 304, 319, 331, 332
A. elliptica 138, 330–332
A. subglobosa 331
Agathis 221, 222, 250, 283
A. australis 221
A. macrophyllus 221
A. vitiensis 221
Alethopteris 86, 89, 93, 106, 109, 111, 113, 115, 329
A. aquilina 108
A. decurrens 95
A. Grandini 108, 117, 144, 325
A. lonchitica 93, 108, 117
A. Serlii 117
Alnus 263
Alstroemeria 304
Amphibennettites 418
A. Bleicheri 418
A. Renaulti 418
Amyelon 261
A. radicans 261
Andrews, E. B. 305
Abies magnifica 75
Acanthocarpus 305
A. xanthioides 305
Acrostichum crinitum 568
Adiantides 173
Adiantites 173
A. bellidulus 173, 174, 307
Aetheotesta 304, 319, 331, 332
A. elliptica 138, 330–332
A. subglobosa 331
Agathis 221, 222, 250, 283
A. australis 221
A. macrophyllus 221
A. vitiensis 221
Alethopteris 86, 89, 93, 106, 109, 111, 113, 115, 329
A. aquilina 108
A. decurrens 95
A. Grandini 108, 117, 144, 325
A. lonchitica 93, 108, 117
A. Serlii 117
Alnus 263
Alstroemeria 304
Amphibennettites 418
A. Bleicheri 418
A. Renaulti 418
Amyelon 261
A. radicans 261
Andrews, E. B. 305
Page 699
Androstrobus 496, 505, 506
A. Balduini 505
A. borealis 505
A. Guerangeri 505
A. Nathorsti 506
A. Scotti 506
A. sibirica 505
A. zamioides 505
Aneimia rotundifolia 539
Aneimites 173
A. fertilis 169, 172
Angiopteris 87, 88, 107
Anomozamites 464, 465, 473, 548–551
A. Balli 586
A. minor 465, 466
A. Muelleri 510, 551
A. Schmidtii 574
Antarcticoxylon 294–299
A. Priestleyi 296–299
Antherangiopsis rediviva 503
Anthodiopsis Beinertiana 126
Antholithes liliacea 264
Antholithus 224, 264
A. Pitcairniae 264
Anthrophyopsis 578, 579
A. crassinervis 581
A. Nilssoni 581
A. obovata 581
Araucaria 222, 250, 251, 299
A. Bidwillii 160
A. imbricata 221
Araucarioxylon 224, 248–250, 295
A. antiquum 285
A. australe 255
A. Balduini 505
A. borealis 505
A. Guerangeri 505
A. Nathorsti 506
A. Scotti 506
A. sibirica 505
A. zamioides 505
Aneimia rotundifolia 539
Aneimites 173
A. fertilis 169, 172
Angiopteris 87, 88, 107
Anomozamites 464, 465, 473, 548–551
A. Balli 586
A. minor 465, 466
A. Muelleri 510, 551
A. Schmidtii 574
Antarcticoxylon 294–299
A. Priestleyi 296–299
Antherangiopsis rediviva 503
Anthodiopsis Beinertiana 126
Antholithes liliacea 264
Antholithus 224, 264
A. Pitcairniae 264
Anthrophyopsis 578, 579
A. crassinervis 581
A. Nilssoni 581
A. obovata 581
Araucaria 222, 250, 251, 299
A. Bidwillii 160
A. imbricata 221
Araucarioxylon 224, 248–250, 295
A. antiquum 285
A. australe 255
Page 700
A. Beinertianum 199
A. saxonicum 253
Araucarites 240, 295, 504
A. Beinertianus 199
A. Brandlingii 254
A. Buchianus 210
A. Oldhami 245
A. Tchihatcheffi 248
Arber, A. 308, 345, 346
Arber, E. A. N. Passim
Arberia, 352
Archaeopitys 290
A. Eastmanni 288, 290
Arctopodium 200–204, 207
A. insigne 201
A. radiatum, 201
Artis, F. E., 247
Artisia, 246–251, 253, 256
A. alternans, 248
A. transversa, 231, 247
Aspleniopteris Nilssoni, 558
Asplenium nidus, 581
Asterochlaena, 203, 205, 207
A. kirgisica, 165
Asterophyllites, 261
Asteropteris noveboracensis, 203
Asterotheca, 168
Attolia speciosa, 327
Aulacopteris, 106
Bambusium, 277
B. Imhofi, 280
Bancroft, N., 147, 446, 455, 489
Beania, 502, 503, 512, 568
A. saxonicum 253
Araucarites 240, 295, 504
A. Beinertianus 199
A. Brandlingii 254
A. Buchianus 210
A. Oldhami 245
A. Tchihatcheffi 248
Arber, A. 308, 345, 346
Arber, E. A. N. Passim
Arberia, 352
Archaeopitys 290
A. Eastmanni 288, 290
Arctopodium 200–204, 207
A. insigne 201
A. radiatum, 201
Artis, F. E., 247
Artisia, 246–251, 253, 256
A. alternans, 248
A. transversa, 231, 247
Aspleniopteris Nilssoni, 558
Asplenium nidus, 581
Asterochlaena, 203, 205, 207
A. kirgisica, 165
Asterophyllites, 261
Asteropteris noveboracensis, 203
Asterotheca, 168
Attolia speciosa, 327
Aulacopteris, 106
Bambusium, 277
B. Imhofi, 280
Bancroft, N., 147, 446, 455, 489
Beania, 502, 503, 512, 568
Page 701
B. Carruthersi, 502, 503
B. gracilis, 502, 503
Bennettites, 367–371
B. dacotensis, 403–408
B. Gibsonianus, 370, 386, 448. See also Cycadeoidea Gibsoniana
B. Morierei, 383, 384, 429, 447. See also Cycadeoidea Morierei
B. portlandicus, 368
B. Saxbyanus, 386
Benson, M., 54, 55, 61–63, 71, 78–81, 125, 226, 228, 275, 313
Berger, R., 335, 341, 342, 349, 354
Berry, E. W., 575
Bertrand, C. E., 214, 267–269, 306, 340
Bertrand and Renault, 219
Bertrand, P., 110–116, 140, 165, 200–205, 210, 323, 335, 342, 348,
357
Bignonia, 336
Binney, E. W., 35, 36, 39, 105
Blastolepis, 460
B. acuminata, 460
B. falcata, 460
B. Otozamitis, 460
Boissier, E., 336
Bolpopodium, 479
Boroviczia, 358, 360, 363
B. Karpinskii, 358–360
Botryoconus, 264, 265
Bowenia, 4, 7–9, 20, 27–29, 87, 139, 315
B. serrulata, 27
B. spectabilis, 20
B. spectabilis var. serrata, 20
Bower, F. O., 12, 196, 475
Braun, A., 12
Braun, F., 475, 477, 537
Brenchley, W. E., 46, 47
B. gracilis, 502, 503
Bennettites, 367–371
B. dacotensis, 403–408
B. Gibsonianus, 370, 386, 448. See also Cycadeoidea Gibsoniana
B. Morierei, 383, 384, 429, 447. See also Cycadeoidea Morierei
B. portlandicus, 368
B. Saxbyanus, 386
Benson, M., 54, 55, 61–63, 71, 78–81, 125, 226, 228, 275, 313
Berger, R., 335, 341, 342, 349, 354
Berry, E. W., 575
Bertrand, C. E., 214, 267–269, 306, 340
Bertrand and Renault, 219
Bertrand, P., 110–116, 140, 165, 200–205, 210, 323, 335, 342, 348,
357
Bignonia, 336
Binney, E. W., 35, 36, 39, 105
Blastolepis, 460
B. acuminata, 460
B. falcata, 460
B. Otozamitis, 460
Boissier, E., 336
Bolpopodium, 479
Boroviczia, 358, 360, 363
B. Karpinskii, 358–360
Botryoconus, 264, 265
Bowenia, 4, 7–9, 20, 27–29, 87, 139, 315
B. serrulata, 27
B. spectabilis, 20
B. spectabilis var. serrata, 20
Bower, F. O., 12, 196, 475
Braun, A., 12
Braun, F., 475, 477, 537
Brenchley, W. E., 46, 47
Page 702
Brongniart, A., Passim
Brown, R., 368, 448, 480
Buckland, W., 367–371, 448
Bucklandia, 372, 368, 408, 425, 426, 478–490, 523, 524, 531, 546
B. anomala, 481–483
B. buzzardensis, 486
B. indica, 488, 489
B. Mantelli, 481
B. Milleriana, 483, 484
B. (Fittonia) Rigauxi, 496
B. Ruffordi, 496
B. Saportana, 481, 569
B. (Fittonia) squamata, 487, 496
B. squamosa, 487
B. Yatesii, 484–86
Buckman, J., 588
Bulbopodium, 368, 369, 479
B. micromerum, 417
Bunbury, C. E. F., 240
Burlingame, L., 62, 312
Calamarieae, 190
Calamopitys, 190–197, 200, 248
C. americana, 193, 200
C. annularis, 193, 194, 198, 199
C. Beinertiana, 199
C. Saturni, 190–194, 198
Calamopteris, 190, 196
C. Hippocrepis, 196
Calamosyrix, 190
Calamoxyleae, 190
Callipteris, 109, 142, 169
Callixylon, 290–293
C. Trifilievi, 291–293
Brown, R., 368, 448, 480
Buckland, W., 367–371, 448
Bucklandia, 372, 368, 408, 425, 426, 478–490, 523, 524, 531, 546
B. anomala, 481–483
B. buzzardensis, 486
B. indica, 488, 489
B. Mantelli, 481
B. Milleriana, 483, 484
B. (Fittonia) Rigauxi, 496
B. Ruffordi, 496
B. Saportana, 481, 569
B. (Fittonia) squamata, 487, 496
B. squamosa, 487
B. Yatesii, 484–86
Buckman, J., 588
Bulbopodium, 368, 369, 479
B. micromerum, 417
Bunbury, C. E. F., 240
Burlingame, L., 62, 312
Calamarieae, 190
Calamopitys, 190–197, 200, 248
C. americana, 193, 200
C. annularis, 193, 194, 198, 199
C. Beinertiana, 199
C. Saturni, 190–194, 198
Calamopteris, 190, 196
C. Hippocrepis, 196
Calamosyrix, 190
Calamoxyleae, 190
Callipteris, 109, 142, 169
Callixylon, 290–293
C. Trifilievi, 291–293
Page 703
Calymmatotheca, 50, 51
C. acuta, 67
C. Stangeri, 50, 57
Cambier and Renier, 235
Cardiocarpon, 264
C. acutum, 169, 337
C. anomalum, 264
C. barcellosum, 351
C. Branneri, 348
C. compressum, 345
C. emarginatum, 335, 389
C. triangulare, 338
Cardiocarpum fluitans, 348
Cardiocarpus, 171, 224, 265, 302, 303, 307, 333–345, 354
C. angustodunensis, 336, 341
C. areolatus, 355
C. bicaudata, 348
C. (Philocarpus) bicornutus, 349
C. cornutus, 350
C. drupaceus, 334, 338
C. drupaceus var. expansus, 339
C. indicus, 140, 141, 352
C. ingens, 353
C. nummularis, 339
C. sclerotesta, 334, 338–340, 356
C. tenuis, 339, 341
Cardiopteris, 136, 360
Carpentier, A., 65–67, 81, 110–113, 365
Carpolites, 363, 364
C. sulcatus, 362
Carpolithes, 353, 497
C. alata, 118
C. conica, 498
C. granulatus, 168
C. acuta, 67
C. Stangeri, 50, 57
Cambier and Renier, 235
Cardiocarpon, 264
C. acutum, 169, 337
C. anomalum, 264
C. barcellosum, 351
C. Branneri, 348
C. compressum, 345
C. emarginatum, 335, 389
C. triangulare, 338
Cardiocarpum fluitans, 348
Cardiocarpus, 171, 224, 265, 302, 303, 307, 333–345, 354
C. angustodunensis, 336, 341
C. areolatus, 355
C. bicaudata, 348
C. (Philocarpus) bicornutus, 349
C. cornutus, 350
C. drupaceus, 334, 338
C. drupaceus var. expansus, 339
C. indicus, 140, 141, 352
C. ingens, 353
C. nummularis, 339
C. sclerotesta, 334, 338–340, 356
C. tenuis, 339, 341
Cardiopteris, 136, 360
Carpentier, A., 65–67, 81, 110–113, 365
Carpolites, 363, 364
C. sulcatus, 362
Carpolithes, 353, 497
C. alata, 118
C. conica, 498
C. granulatus, 168
Page 704
C. Lindleyi, 264
C. membranaceus, 355
C. Milleri, 141
C. nitidulus, 174
C. samaroides, 356
C. sulcata, 359, 362
Carpolithus, 326, 363–365, 497–500
C. bivalvis, 365
C. Bucklandi, 498
C. conicus, 365, 498, 499
C. Nathorsti, 66
C. Pomelii, 499
C. Wildii, 325, 365
Carruthers, W., Passim
Cassytha, 302
Caulopteris Adamsi, 245
Cephalotaxus, 346
C. pedunculata, 222
Ceratozamia, 6, 9, 10, 19, 24, 28, 409, 507, 529
Ceratozamia Hofmanni, 508
C. mexicana, 16, 19, 21, 22, 30, 281, 536
Ceropegia peltata, 247
Chamberlain, C. J., 9, 29, 391
Cheilanthites elegans, 72
Chodat, R., 53, 54, 60, 116, 161
Cladoxyleae, 200–210
Cladoxylon, 165, 200–207, 209, 210
C. dubium, 201, 202
C. Kidstoni, 149, 205, 206, 213
C. mirabile, 201–203, 206
C. taeniatum, 202, 205
Clathraria, 480, 490
C. anomala, 481, 491
C. Lyelli, 480, 481
C. membranaceus, 355
C. Milleri, 141
C. nitidulus, 174
C. samaroides, 356
C. sulcata, 359, 362
Carpolithus, 326, 363–365, 497–500
C. bivalvis, 365
C. Bucklandi, 498
C. conicus, 365, 498, 499
C. Nathorsti, 66
C. Pomelii, 499
C. Wildii, 325, 365
Carruthers, W., Passim
Cassytha, 302
Caulopteris Adamsi, 245
Cephalotaxus, 346
C. pedunculata, 222
Ceratozamia, 6, 9, 10, 19, 24, 28, 409, 507, 529
Ceratozamia Hofmanni, 508
C. mexicana, 16, 19, 21, 22, 30, 281, 536
Ceropegia peltata, 247
Chamberlain, C. J., 9, 29, 391
Cheilanthites elegans, 72
Chodat, R., 53, 54, 60, 116, 161
Cladoxyleae, 200–210
Cladoxylon, 165, 200–207, 209, 210
C. dubium, 201, 202
C. Kidstoni, 149, 205, 206, 213
C. mirabile, 201–203, 206
C. taeniatum, 202, 205
Clathraria, 480, 490
C. anomala, 481, 491
C. Lyelli, 480, 481
Page 705
Clathropodium foratum, 479
C. sarlatense, 479
Clepsydropsis, 204, 205
Codonospermum, 138, 304, 319, 330, 331, 361
C. anomalum, 330, 331, 359
C. olivaeforme, 330, 331
Codonotheca, 67, 124–126, 128
C. caduca, 67, 124, 125
C. pusilla, 126
Coenoxylon, 252, 293, 294
C. Scotti, 293
Colpospermum, 362, 363
Colpoxylon, 109, 142–145, 283
C. aeduense, 109, 142, 143
Colymbetes, 491–494
C. Edwardsi, 491–494
Compsotesta, 333, 347
C. Brongniarti, 347
Compter, G., 280, 500
Condylites, 467
C. squamatus, 467
Conites Bucklandi, 487
Conostoma, 64, 71, 79, 81, 303, 306, 309, 312–317, 326
C. anglo-germanicum, 315
C. intermedianum, 79
C. oblongum, 308, 313–315
C. ovale, 79
Corda, A. J., 70, 200, 223, 281, 504, 505
Cordaianthus, 142, 220, 224, 264–270
C. acicularis, 267
C. Grand’Euryi, 268, 269
C. Lacattii, 268
C. Minieri, 279
C. Pitcairniae, 232, 233, 266, 267
C. sarlatense, 479
Clepsydropsis, 204, 205
Codonospermum, 138, 304, 319, 330, 331, 361
C. anomalum, 330, 331, 359
C. olivaeforme, 330, 331
Codonotheca, 67, 124–126, 128
C. caduca, 67, 124, 125
C. pusilla, 126
Coenoxylon, 252, 293, 294
C. Scotti, 293
Colpospermum, 362, 363
Colpoxylon, 109, 142–145, 283
C. aeduense, 109, 142, 143
Colymbetes, 491–494
C. Edwardsi, 491–494
Compsotesta, 333, 347
C. Brongniarti, 347
Compter, G., 280, 500
Condylites, 467
C. squamatus, 467
Conites Bucklandi, 487
Conostoma, 64, 71, 79, 81, 303, 306, 309, 312–317, 326
C. anglo-germanicum, 315
C. intermedianum, 79
C. oblongum, 308, 313–315
C. ovale, 79
Corda, A. J., 70, 200, 223, 281, 504, 505
Cordaianthus, 142, 220, 224, 264–270
C. acicularis, 267
C. Grand’Euryi, 268, 269
C. Lacattii, 268
C. Minieri, 279
C. Pitcairniae, 232, 233, 266, 267
Page 706
C. Volkmanni, 266, 267
C. Williamsoni, 267, 268
C. Zeilleri, 268
Cordaicarpon, 334
C. Cordai, 334, 335
Cordaicarpus, 220, 224, 240, 266, 333, 334, 335, 337, 342, 364
C. Cordai, 232, 350, 354, 355
C. ingens, 353
Cordaicladus, 220, 224, 245
Cordaioxylon, 220, 223, 248, 250
C. Brandlingii, 254
Cordaispermum, 335
Cordaitales, 214–299
Cordaiteae, 219–284
Cordaites, 137, 175, 176, 211, 214–217, 219–283 (passim), 294, 299,
335
C. aequalis, 238, 239, 243
C. australis, 240
C. borassifolius, 233, 236, 281
C. circularis, 139, 237, 276
C. Clerci, 239, 243
C. communis, 233
C. crassifolius, 226, 237
C. crassus, 226
C. Delvali, 235
C. Felicis, 226, 228, 230, 275
C. gracilis, 236
C. grandifolius, 235, 276
C. (Noeggerathiopsis) Hislopi, 238–245, 262
C. Lacoei, 237
C. lancifolius, 233
C. linearis, 236
C. lingulatus, 227, 229, 233–235
C. Mansfieldi, 232
C. Williamsoni, 267, 268
C. Zeilleri, 268
Cordaicarpon, 334
C. Cordai, 334, 335
Cordaicarpus, 220, 224, 240, 266, 333, 334, 335, 337, 342, 364
C. Cordai, 232, 350, 354, 355
C. ingens, 353
Cordaicladus, 220, 224, 245
Cordaioxylon, 220, 223, 248, 250
C. Brandlingii, 254
Cordaispermum, 335
Cordaitales, 214–299
Cordaiteae, 219–284
Cordaites, 137, 175, 176, 211, 214–217, 219–283 (passim), 294, 299,
335
C. aequalis, 238, 239, 243
C. australis, 240
C. borassifolius, 233, 236, 281
C. circularis, 139, 237, 276
C. Clerci, 239, 243
C. communis, 233
C. crassifolius, 226, 237
C. crassus, 226
C. Delvali, 235
C. Felicis, 226, 228, 230, 275
C. gracilis, 236
C. grandifolius, 235, 276
C. (Noeggerathiopsis) Hislopi, 238–245, 262
C. Lacoei, 237
C. lancifolius, 233
C. linearis, 236
C. lingulatus, 227, 229, 233–235
C. Mansfieldi, 232
Page 707
C. microstachys, 236
C. Newberryi, 293
C. Ottonis, 232
C. palmaeformis, 235
C. principalis, 226, 229–233, 266, 335
C. Robbii, 233, 350
C. robustus, 227
Cordaixylon, 223
Cornucarpus, 337
C. acutus, 337
Corylus colurna, 60
Corypha, 381
Cotta, C. B., 89, 96, 105
Crié, L., 255
Crossotheca, 52–54, 113
C. Hoeninghausi, 53, 54, 57
C. Hughesiana, 52
Crossozamia, 368, 500, 529
C. Hennocquei, 500
C. Moraeana, 500
Ctenidopsis, 580
Ctenis, 511, 512, 532, 578–583
C. asplenioides, 581, 582
C. falcata, 532, 580, 582
C. fallax, 581
C. hungarica, 580, 581
C. Kaneharai, 582
C. latifolia, 583
C. lunzensis, 580
C. orovillensis, 582, 583
C. Potocki, 580, 582–584
C. remotinervis, 582
C. sulcicaulis, 580, 582–584, 586, 587
C. Zeyschneri, 580, 582
C. Newberryi, 293
C. Ottonis, 232
C. palmaeformis, 235
C. principalis, 226, 229–233, 266, 335
C. Robbii, 233, 350
C. robustus, 227
Cordaixylon, 223
Cornucarpus, 337
C. acutus, 337
Corylus colurna, 60
Corypha, 381
Cotta, C. B., 89, 96, 105
Crié, L., 255
Crossotheca, 52–54, 113
C. Hoeninghausi, 53, 54, 57
C. Hughesiana, 52
Crossozamia, 368, 500, 529
C. Hennocquei, 500
C. Moraeana, 500
Ctenidopsis, 580
Ctenis, 511, 512, 532, 578–583
C. asplenioides, 581, 582
C. falcata, 532, 580, 582
C. fallax, 581
C. hungarica, 580, 581
C. Kaneharai, 582
C. latifolia, 583
C. lunzensis, 580
C. orovillensis, 582, 583
C. Potocki, 580, 582–584
C. remotinervis, 582
C. sulcicaulis, 580, 582–584, 586, 587
C. Zeyschneri, 580, 582
Page 708
Ctenophyllum, 528
C. angustifolium, 556
C. grandifolium, 585
C. latifolium, 585
C. pecten, 528
C. Wardi, 585
Ctenopsis, 585
Ctenopteris, 511, 512
Cyathea, 88
Cycadales, 1–34
Cycadeae, 8
Cycadella, 374, 385, 417, 418
C. ramentosa, 379, 417
C. wyomingensis, 418
Cycadeoidea, 282, 367–417
C. buzzardensis, 372, 486
C. colossalis, 382, 408–410
C. dacotensis, 403–408, 434, 449
C. Dartoni, 380, 384
C. etrusca, 384, 438
C. excelsa, 374
C. Gibsoniana, 374, 377, 386–395, 411, 420, 455, 456, 470
C. gigantea, 372, 380, 411–416, 478
C. ingens, 378
C. Jenneyana, 372, 375, 412, 416
C. McBridei, 403
C. Marshiana, 372, 408, 409, 412
C. marylandica, 373
C. megalophylla, 367
C. micromyela, 369, 374, 376, 415, 418, 456, 488
C. microphylla, 367, 371
C. montiana, 384
C. Morierei, 395–403, 456, 456, 478
C. nana, 372
C. angustifolium, 556
C. grandifolium, 585
C. latifolium, 585
C. pecten, 528
C. Wardi, 585
Ctenopsis, 585
Ctenopteris, 511, 512
Cyathea, 88
Cycadales, 1–34
Cycadeae, 8
Cycadella, 374, 385, 417, 418
C. ramentosa, 379, 417
C. wyomingensis, 418
Cycadeoidea, 282, 367–417
C. buzzardensis, 372, 486
C. colossalis, 382, 408–410
C. dacotensis, 403–408, 434, 449
C. Dartoni, 380, 384
C. etrusca, 384, 438
C. excelsa, 374
C. Gibsoniana, 374, 377, 386–395, 411, 420, 455, 456, 470
C. gigantea, 372, 380, 411–416, 478
C. ingens, 378
C. Jenneyana, 372, 375, 412, 416
C. McBridei, 403
C. Marshiana, 372, 408, 409, 412
C. marylandica, 373
C. megalophylla, 367
C. micromyela, 369, 374, 376, 415, 418, 456, 488
C. microphylla, 367, 371
C. montiana, 384
C. Morierei, 395–403, 456, 456, 478
C. nana, 372
Page 709
C. Niedźwiedzkii, 412
C. nigra, 374
C. Peachiana, 388
C. pumila, 369, 372, 417
C. pygmaea, 368, 417
C. Reichenbachiana, 409–412, 416
C. Saxbyana, 386, 388
C. Stilwelli, 374
C. superba, 372, 408
C. Wielandi, 375, 376
C. Yatesii, 371, 372, 484
Cycadeomyelon, 481, 490, 491
C. Apperti, 490, 491
C. densicristatum, 491
Cycadeorachis, 591
Cycadeospermum, 496, 497
C. Pomelii, 499
Cycadeostrobus, 503, 504
C. Brunonis, 504
C. elegans, 504
C. sphaericus, 504
C. truncatus, 504
Cycadinocarpus, 333, 334, 336, 341, 496, 497
C. angustodunensia, 326, 341
Cycadites, 367, 368, 529, 558–672
C. Blandfordianus, 561
C. confertus, 561
C. constrictus, 561
C. gramineus, 561
C. gyrosus, 509, 562
C. pecten, 520, 522
C. pectinoides, 520, 522
C. rajmahalensis, 571, 572
C. rectangularis, 501, 565, 566
C. nigra, 374
C. Peachiana, 388
C. pumila, 369, 372, 417
C. pygmaea, 368, 417
C. Reichenbachiana, 409–412, 416
C. Saxbyana, 386, 388
C. Stilwelli, 374
C. superba, 372, 408
C. Wielandi, 375, 376
C. Yatesii, 371, 372, 484
Cycadeomyelon, 481, 490, 491
C. Apperti, 490, 491
C. densicristatum, 491
Cycadeorachis, 591
Cycadeospermum, 496, 497
C. Pomelii, 499
Cycadeostrobus, 503, 504
C. Brunonis, 504
C. elegans, 504
C. sphaericus, 504
C. truncatus, 504
Cycadinocarpus, 333, 334, 336, 341, 496, 497
C. angustodunensia, 326, 341
Cycadites, 367, 368, 529, 558–672
C. Blandfordianus, 561
C. confertus, 561
C. constrictus, 561
C. gramineus, 561
C. gyrosus, 509, 562
C. pecten, 520, 522
C. pectinoides, 520, 522
C. rajmahalensis, 571, 572
C. rectangularis, 501, 565, 566
Page 710
C. Renaulti, 566
C. Roemeri, 559
C. Saladini, 565
C. Saportae, 14, 559
C. sibiricus, 561
C. Steenstrupi, 559
C. sulcicaulis, 578
C. taxodinus, 509, 562
C. tenuisectus, 563, 576
Cycadocephalus, 473–477
C. Sewardi, 473–475
Cycadolepis, 482, 494–496
C. pilosa, 494
C. villosa, 494
Cycadorachis, 590, 591
C. abscissa, 590
C. armata, 590
C. tuberculata, 591
Cycadospadix, 141, 494, 500, 501, 504
C. Hennocquei, 501
C. integer, 501
C. Milleryensis, 338
C. Pasinianus, 500
Cycadoxylon, 185–187
C. Fremyi, 186, 187
C. robustum, 186, 187
Cycas, 4–13, 27, 29, 34, 89, 94, 109, 157, etc.
C. angulata, 21
C. Beddomei, 13
C. Cairnsiana, 14
C. circinalis, 4, 13, 16, 20, 21, 24, 25, 27
C. media, 30, 33
C. Micholitzii, 13, 14, 33
C. pectinata, 21, 22
C. Roemeri, 559
C. Saladini, 565
C. Saportae, 14, 559
C. sibiricus, 561
C. Steenstrupi, 559
C. sulcicaulis, 578
C. taxodinus, 509, 562
C. tenuisectus, 563, 576
Cycadocephalus, 473–477
C. Sewardi, 473–475
Cycadolepis, 482, 494–496
C. pilosa, 494
C. villosa, 494
Cycadorachis, 590, 591
C. abscissa, 590
C. armata, 590
C. tuberculata, 591
Cycadospadix, 141, 494, 500, 501, 504
C. Hennocquei, 501
C. integer, 501
C. Milleryensis, 338
C. Pasinianus, 500
Cycadoxylon, 185–187
C. Fremyi, 186, 187
C. robustum, 186, 187
Cycas, 4–13, 27, 29, 34, 89, 94, 109, 157, etc.
C. angulata, 21
C. Beddomei, 13
C. Cairnsiana, 14
C. circinalis, 4, 13, 16, 20, 21, 24, 25, 27
C. media, 30, 33
C. Micholitzii, 13, 14, 33
C. pectinata, 21, 22
Page 711
C. revoluta, 5, 7, 10, 22, 27, 30
C. Ruiminiana, 21, 22
C. Rumphii, 20
C. Rumphii var. bifida, 13
C. siamensis, 11, 12, 27, 30, 160
Cyclocarpon, 334–336, 349
C. nummularium, 335
C. tenue, 335
Cyclocarpus, 340, 346
C. nummularis, 341
Cyclopteris, 109, 130, 136, 139, 276, 496
C. Jenksiniana, 496
C. Klipsteinii, 544
Cyclospermum, 333, 335, 340, 341
Cyclozamia, 541
Cylindropodium, 368, 386, 478, 479
Dadoxylon, 223, 248–260, 289–295
D. australe, 252, 255, 256
D. Brandlingii, 251, 254, 260
D. Buchianum, 220
D. Kayi, 256, 258
D. materiarum, 252, 256, 257
D. medullaris, 254
D. meridionale, 255
D. Newberryi, 252
D. Nicoli, 255
D. nummularium, 255
D. oldhamium, 35, 38
D. ouangonidium, 252
D. Pedroi, 252, 258, 259, 275
D. permiense, 259
D. protopityoides, 255
D. Spenceri, 294
C. Ruiminiana, 21, 22
C. Rumphii, 20
C. Rumphii var. bifida, 13
C. siamensis, 11, 12, 27, 30, 160
Cyclocarpon, 334–336, 349
C. nummularium, 335
C. tenue, 335
Cyclocarpus, 340, 346
C. nummularis, 341
Cyclopteris, 109, 130, 136, 139, 276, 496
C. Jenksiniana, 496
C. Klipsteinii, 544
Cyclospermum, 333, 335, 340, 341
Cyclozamia, 541
Cylindropodium, 368, 386, 478, 479
Dadoxylon, 223, 248–260, 289–295
D. australe, 252, 255, 256
D. Brandlingii, 251, 254, 260
D. Buchianum, 220
D. Kayi, 256, 258
D. materiarum, 252, 256, 257
D. medullaris, 254
D. meridionale, 255
D. Newberryi, 252
D. Nicoli, 255
D. nummularium, 255
D. oldhamium, 35, 38
D. ouangonidium, 252
D. Pedroi, 252, 258, 259, 275
D. permiense, 259
D. protopityoides, 255
D. Spenceri, 294
Page 712
D. spetzbergense, 260
Dammara albens, 281
Dammarites Bayeri, 283
Danaea elliptica, 475
Davallia aculeata, 48
D. tenuifolia, 77
Dawes, J. S., 247
Dawson, Sir J. W., 173, 203, 238, 247, 256, 277, 463
Dawson and Matthew, 252
Dawson and Penhallow, 196
De la Beche, 540
Decagonocarpus, 357
D. olivaeformis, 357
Depape and Carpentier, 317
Desmiophyllum, 236, 278
D. Solmsi, 282
Dicksonites, 167
Dicranophyllum, 246
Dictyo-Cordaites Lecoi, 238
Dictyopteris, 546
D. falcata, 546
D. Schützii, 113
Dictyothalamus, 127
D. Schrollianus, 113, 127
Dictyoxylon, 35, 36, 72
D. Grievii, 72
D. oldhamium, 38
D. radicans, 261
Dictyozamites, 379, 511, 546–548
D. falcatus, 546
D. falcatus var. distans, 547
D. falcatus var. grossinervis, 547
D. falcatus var. obtusa, 546
D. grossinervis, 547
Dammara albens, 281
Dammarites Bayeri, 283
Danaea elliptica, 475
Davallia aculeata, 48
D. tenuifolia, 77
Dawes, J. S., 247
Dawson, Sir J. W., 173, 203, 238, 247, 256, 277, 463
Dawson and Matthew, 252
Dawson and Penhallow, 196
De la Beche, 540
Decagonocarpus, 357
D. olivaeformis, 357
Depape and Carpentier, 317
Desmiophyllum, 236, 278
D. Solmsi, 282
Dicksonites, 167
Dicranophyllum, 246
Dictyo-Cordaites Lecoi, 238
Dictyopteris, 546
D. falcata, 546
D. Schützii, 113
Dictyothalamus, 127
D. Schrollianus, 113, 127
Dictyoxylon, 35, 36, 72
D. Grievii, 72
D. oldhamium, 38
D. radicans, 261
Dictyozamites, 379, 511, 546–548
D. falcatus, 546
D. falcatus var. distans, 547
D. falcatus var. grossinervis, 547
D. falcatus var. obtusa, 546
D. grossinervis, 547
Page 713
D. Hawelli, 547, 548
D. indicus, 346
D. Johnstrupi, 547, 548
Dioon, 8, 9, 19, 29, 30, 455
D. edule, 10, 15, 16, 19, 27, 28, 34, 464
D. Purpusii, 19
D. spinulosum, 10, 19, 23, 25, 417
Dioonites, 509, 528, 556, 572
D. Buchianus, 537
D. saxonicus, 537
D. spectabilis, 367
Diplopterotesta, 360, 361
D. spitzbergensis, 359, 360
Diplotesta, 265, 333, 346, 347
D. avellana, 322
D. Grand’Euryana, 322, 346
Diplotmema, 77
D. elegans, 72
Dolerophylleae, 132
Dolerophyllum, 124, 130–139, 229, 237, 276, 331, 332
D. Berthieri, 130, 133, 136–138
D. fertile, 130, 131, 137, 138
D. Goepperti, 132–134, 137, 138
D. pseudopeltatum, 136, 137
Doleropteris, 136
Doleropteroideae, 132
Dorety, H. A., 30, 162
Dorrien-Smith, A. A., 25
Dory-Cordaites, 224, 227, 265, 321
Dory-Cycadolepis, 494
Dunker, W., 528, 529, 544, 558
Duns, J., 170
Echinostipes, 368
D. indicus, 346
D. Johnstrupi, 547, 548
Dioon, 8, 9, 19, 29, 30, 455
D. edule, 10, 15, 16, 19, 27, 28, 34, 464
D. Purpusii, 19
D. spinulosum, 10, 19, 23, 25, 417
Dioonites, 509, 528, 556, 572
D. Buchianus, 537
D. saxonicus, 537
D. spectabilis, 367
Diplopterotesta, 360, 361
D. spitzbergensis, 359, 360
Diplotesta, 265, 333, 346, 347
D. avellana, 322
D. Grand’Euryana, 322, 346
Diplotmema, 77
D. elegans, 72
Dolerophylleae, 132
Dolerophyllum, 124, 130–139, 229, 237, 276, 331, 332
D. Berthieri, 130, 133, 136–138
D. fertile, 130, 131, 137, 138
D. Goepperti, 132–134, 137, 138
D. pseudopeltatum, 136, 137
Doleropteris, 136
Doleropteroideae, 132
Dorety, H. A., 30, 162
Dorrien-Smith, A. A., 25
Dory-Cordaites, 224, 227, 265, 321
Dory-Cycadolepis, 494
Dunker, W., 528, 529, 544, 558
Duns, J., 170
Echinostipes, 368
Page 714
Edraxylon, 38, 47
Edwards, W. N., 343
Eichwald, E., 132
Elkins and Wieland, 292
Encephalartopsis, 508
E. nervosa, 508, 580
Encephalartos, 6–10, 14, 23, 28, 29, 34, 158, 372, 487, 507, 508, 529,
587
E. Altensteinii, 14, 15, 21, 25, 27, 412
E. Barteri, 9, 27, 30, 158
E. caffer, 14, 16
E. cretaceus, 508
E. denticulatus, 507
E. Fredericki-Guilielmi, 14, 16
E. Ghellinckii, 11, 14, 529, 561
E. Gorciexianus, 508, 510
E. Hildebrandti, 9
E. horridus, 27
E. Laurentianus, 14
E. Lehmanni, 14, 320
E. longifolia, 14, 536
E. villosus, 22
Endlicher, S., 285, 503
Endolepis vogesiacus, 278
Eolirion primigenium, 282
Eremopteris, 169–172
E. artemisaefolia, 169–171
E. Macconchii, 172
E. Neesii, 169
Eriotesta, 319, 332
E. vetutina, 332
Eristophyton, 194, 197, 200, 248
E. Beinertianum, 199, 295
E. fasciculare, 197–199
Edwards, W. N., 343
Eichwald, E., 132
Elkins and Wieland, 292
Encephalartopsis, 508
E. nervosa, 508, 580
Encephalartos, 6–10, 14, 23, 28, 29, 34, 158, 372, 487, 507, 508, 529,
587
E. Altensteinii, 14, 15, 21, 25, 27, 412
E. Barteri, 9, 27, 30, 158
E. caffer, 14, 16
E. cretaceus, 508
E. denticulatus, 507
E. Fredericki-Guilielmi, 14, 16
E. Ghellinckii, 11, 14, 529, 561
E. Gorciexianus, 508, 510
E. Hildebrandti, 9
E. horridus, 27
E. Laurentianus, 14
E. Lehmanni, 14, 320
E. longifolia, 14, 536
E. villosus, 22
Endlicher, S., 285, 503
Endolepis vogesiacus, 278
Eolirion primigenium, 282
Eremopteris, 169–172
E. artemisaefolia, 169–171
E. Macconchii, 172
E. Neesii, 169
Eriotesta, 319, 332
E. vetutina, 332
Eristophyton, 194, 197, 200, 248
E. Beinertianum, 199, 295
E. fasciculare, 197–199
Page 715
Erodium, 304, 364
Ettingshausen, C. von, 529, 551, 578, 581
Eu-Cordaites, 224
Eu-Ctenis, 580
Euphorbia, 247
Eury-Cycadolepis, 494–496
E. Jenkinsiana, 496
Euryphyllum, 238, 245
Eu-Zamites, 521, 531
Feistmantel, O., 240, 443, 445, 494, 514–517, 546, 561, 572, 574, 577,
586
Feistmantelia, 139, 491
F. bengalensis, 139
F. oblonga, 491
Felix, J., 67, 70, 227, 250
Fiedler, H., 123, 335, 336, 349, 351
Filicites Bechei, 539, 540
F. Bucklandi, 537
F. (Sphenopteris) elegans, 72
F. Pluckeneti, 166
Fittonia, 478, 487
F. Brongniarti, 395
F. insignis, 487
F. Rigauxi, 487
F. Ruffordi, 483
F. squamata, 487
Flabellaria, 223, 233
F. chamaeropifolia, 281
Fliche, P., 278, 279, 280, 368, 504
Fontaine, W. M., 385, 500, 508, 578, 580, 582
Fraine, E. de, 95, 96, 149, 153, 155, 161
Fričia nobilis, 505
Fries, E., 566
Fumaria officinalis, 72
Ettingshausen, C. von, 529, 551, 578, 581
Eu-Cordaites, 224
Eu-Ctenis, 580
Euphorbia, 247
Eury-Cycadolepis, 494–496
E. Jenkinsiana, 496
Euryphyllum, 238, 245
Eu-Zamites, 521, 531
Feistmantel, O., 240, 443, 445, 494, 514–517, 546, 561, 572, 574, 577,
586
Feistmantelia, 139, 491
F. bengalensis, 139
F. oblonga, 491
Felix, J., 67, 70, 227, 250
Fiedler, H., 123, 335, 336, 349, 351
Filicites Bechei, 539, 540
F. Bucklandi, 537
F. (Sphenopteris) elegans, 72
F. Pluckeneti, 166
Fittonia, 478, 487
F. Brongniarti, 395
F. insignis, 487
F. Rigauxi, 487
F. Ruffordi, 483
F. squamata, 487
Flabellaria, 223, 233
F. chamaeropifolia, 281
Fliche, P., 278, 279, 280, 368, 504
Fontaine, W. M., 385, 500, 508, 578, 580, 582
Fraine, E. de, 95, 96, 149, 153, 155, 161
Fričia nobilis, 505
Fries, E., 566
Fumaria officinalis, 72
Page 716
Gangamopteris, 258, 338, 352
G. Seixasi, 351
Gaudrya, 319, 332
G. lagenaria, 332
G. trivalvis, 332
Geinitz, H. B., 334, 365, 552
Gibbs, L. S., 61
Ginkgo biloba, 7, 61, 62, 119, 135, 139, 173, 222, 251, 266, 294, 301,
306, 327, 333, 338, 339, 398, 499, 502
Gleichenia, 74, 88
Glossopteris, 141, 354
G. indica, 140
Glossozamites, 530
G. brevis, 530
G. Schenkii, 541
G. Stoliczanus, 530
Glyptostrobus, 127
Gnetales, 160
Gnetopsis, 304, 309, 314, 317, 318
G. anglica, 318
G. elliptica, 314, 317, 318, 359
Gnetum, 401
G. africanum, 401
G. Gnemon, 63
Goeppert, H. R., 96, 126, 127, 173, 210, 264, 285, 289, 295, 305, 336,
411, 412, 527
Goeppert and Stenzel, 86, 96, 102, 163, 252, 295
Goldenburg, F., 236
Gomphostrobus, 253
Gordon, W. T., 181, 183, 288, 312
Gothan, W., 51, 248–252
Gourlie, W., 36, 37
Grand’Eury, C., Passim
Grieve, G., 72
G. Seixasi, 351
Gaudrya, 319, 332
G. lagenaria, 332
G. trivalvis, 332
Geinitz, H. B., 334, 365, 552
Gibbs, L. S., 61
Ginkgo biloba, 7, 61, 62, 119, 135, 139, 173, 222, 251, 266, 294, 301,
306, 327, 333, 338, 339, 398, 499, 502
Gleichenia, 74, 88
Glossopteris, 141, 354
G. indica, 140
Glossozamites, 530
G. brevis, 530
G. Schenkii, 541
G. Stoliczanus, 530
Glyptostrobus, 127
Gnetales, 160
Gnetopsis, 304, 309, 314, 317, 318
G. anglica, 318
G. elliptica, 314, 317, 318, 359
Gnetum, 401
G. africanum, 401
G. Gnemon, 63
Goeppert, H. R., 96, 126, 127, 173, 210, 264, 285, 289, 295, 305, 336,
411, 412, 527
Goeppert and Stenzel, 86, 96, 102, 163, 252, 295
Goldenburg, F., 236
Gomphostrobus, 253
Gordon, W. T., 181, 183, 288, 312
Gothan, W., 51, 248–252
Gourlie, W., 36, 37
Grand’Eury, C., Passim
Grieve, G., 72
Page 717
Griffith, W., 28, 302
Guilelmites, 365
Halle, T. G., 280, 443, 457, 473, 517, 518, 521, 522, 527, 540, 547,
550, 563, 565, 575
Haplocalamus, 190
Heer, O., 174, 280, 336, 358, 360, 462, 520, 525, 530, 541, 549, 563
Helmacher, R., 349
Hemingway, W., 94, 317
Hemitelia, 48
Heterangium, 51, 70–85, 86–94, 98, 109, 156, 157, 162, 168, 179–183,
193, 194, 214, 309, 312, 316
H. alatum, 84
H. Andrei, 84
H. bibractense, 84
H. bohemicum, 84
H. cylindricum, 83
H. Duchartrei, 83
H. Grievii, 71–73, 79–82
H. hibernicum, 84
H. Lomaxi, 72, 83
H. minimum, 83
H. paradoxum, 72
H. polystichum, 84
H. punctatum, 84
H. Renaulti, 84
H. Sturi, 84, 183
H. tiliaeoidea, 71, 81–84
Hexagonocarpus, 116, 303, 322, 323, 356
H. crassus, 356
H. Hookeri, 357
H. Noeggerathi, 359
Hexapterospermum, 116, 119, 140, 319, 321–323, 348, 356
H. modestae, 357
H. Noeggerathii, 322, 357
Guilelmites, 365
Halle, T. G., 280, 443, 457, 473, 517, 518, 521, 522, 527, 540, 547,
550, 563, 565, 575
Haplocalamus, 190
Heer, O., 174, 280, 336, 358, 360, 462, 520, 525, 530, 541, 549, 563
Helmacher, R., 349
Hemingway, W., 94, 317
Hemitelia, 48
Heterangium, 51, 70–85, 86–94, 98, 109, 156, 157, 162, 168, 179–183,
193, 194, 214, 309, 312, 316
H. alatum, 84
H. Andrei, 84
H. bibractense, 84
H. bohemicum, 84
H. cylindricum, 83
H. Duchartrei, 83
H. Grievii, 71–73, 79–82
H. hibernicum, 84
H. Lomaxi, 72, 83
H. minimum, 83
H. paradoxum, 72
H. polystichum, 84
H. punctatum, 84
H. Renaulti, 84
H. Sturi, 84, 183
H. tiliaeoidea, 71, 81–84
Hexagonocarpus, 116, 303, 322, 323, 356
H. crassus, 356
H. Hookeri, 357
H. Noeggerathi, 359
Hexapterospermum, 116, 119, 140, 319, 321–323, 348, 356
H. modestae, 357
H. Noeggerathii, 322, 357
Page 718
H. pachypterum, 321
H. stenopterum, 321, 322
Hick, T., 67
Hierogramma, 200–204
H. mysticum, 201
Hisingera, 569
Holcospermum, 343, 361–363
H. dubium, 363
H. sulcatum, 357, 359, 361–363
Holden, H. S., 109
Holden, R., 243, 559, 560, 563, 565
Hollick, A., 461
Hollick and Jeffrey, 491
Hooker, Sir J., 10, 60
Hooker and Binney, 118, 301
Howse, R., 170, 232
Hysterites Cordaitis, 233
Iodes, 46
Johnson, T., 51, 52, 84
Jordania, 334, 336
J. bignonioides, 336, 351
J. moravica, 347
Juglans, 222
J. regia, 246
Kaloxylon, 67
K. Hookeri, 38, 67
Kalymma, 190, 192, 194–196
K. grandis, 192, 195, 196
K. striata, 196
Karsten, G., 30
Kershaw, E. M., 28, 61
Kidston, R., 51–53, 56, 110, 112, 168
H. stenopterum, 321, 322
Hick, T., 67
Hierogramma, 200–204
H. mysticum, 201
Hisingera, 569
Holcospermum, 343, 361–363
H. dubium, 363
H. sulcatum, 357, 359, 361–363
Holden, H. S., 109
Holden, R., 243, 559, 560, 563, 565
Hollick, A., 461
Hollick and Jeffrey, 491
Hooker, Sir J., 10, 60
Hooker and Binney, 118, 301
Howse, R., 170, 232
Hysterites Cordaitis, 233
Iodes, 46
Johnson, T., 51, 52, 84
Jordania, 334, 336
J. bignonioides, 336, 351
J. moravica, 347
Juglans, 222
J. regia, 246
Kaloxylon, 67
K. Hookeri, 38, 67
Kalymma, 190, 192, 194–196
K. grandis, 192, 195, 196
K. striata, 196
Karsten, G., 30
Kershaw, E. M., 28, 61
Kidston, R., 51–53, 56, 110, 112, 168
Page 719
Kidston and Gwynne-Vaughan, 185
Klein, L., 145
Knorria taxina, 232
Kosmovsky, C., 238
Krammera, 277, 281
K. mirabilis, 280
Krasser, F., 420, 553, 576, 580
Kraus, G., 28, 210, 295
Kubart, B., 70, 71, 84, 183
Kurtz, F., 589
Kutorga, S., 132
Lagenidium, 62
Lagenospermum, 64–66, 174, 309
L. Arberi, 173, 307
L. glandiforme, 360
L. nitidulum, 174
L. oblongum, 65, 66
L. Sinclairi, 57, 64, 66, 81
Lagenostoma, 55–66, 71, 81, 116, 122, 125, 160, 173, 303, 307–317,
325, 326, 329, 497
L. Kidstoni, 64
L. Lomaxi, 51, 55–62, 311
L. oblonga, 65
L. ovoides, 55, 62–64, 311
L. physoides, 62, 301
L. Sinclairi, 64, 65
L. urceolaris, 65
Leckenby, J., 421
Lepidanthium, 477
Lepidocaryon, 265, 333, 346, 347
L. avellana, 346
Lepidodendron, 125, 212, 271
Leslie, T. N., 242, 256
Lesquereux, L., 110, 123, 131, 156, 232, 235, 305, 326
Klein, L., 145
Knorria taxina, 232
Kosmovsky, C., 238
Krammera, 277, 281
K. mirabilis, 280
Krasser, F., 420, 553, 576, 580
Kraus, G., 28, 210, 295
Kubart, B., 70, 71, 84, 183
Kurtz, F., 589
Kutorga, S., 132
Lagenidium, 62
Lagenospermum, 64–66, 174, 309
L. Arberi, 173, 307
L. glandiforme, 360
L. nitidulum, 174
L. oblongum, 65, 66
L. Sinclairi, 57, 64, 66, 81
Lagenostoma, 55–66, 71, 81, 116, 122, 125, 160, 173, 303, 307–317,
325, 326, 329, 497
L. Kidstoni, 64
L. Lomaxi, 51, 55–62, 311
L. oblonga, 65
L. ovoides, 55, 62–64, 311
L. physoides, 62, 301
L. Sinclairi, 64, 65
L. urceolaris, 65
Leckenby, J., 421
Lepidanthium, 477
Lepidocaryon, 265, 333, 346, 347
L. avellana, 346
Lepidodendron, 125, 212, 271
Leslie, T. N., 242, 256
Lesquereux, L., 110, 123, 131, 156, 232, 235, 305, 326
Page 720
Leuthardt, F., 280, 550, 553
Lignier, O., 34, 63, 217, 229, 247, 386, 415, 428, 432–434, 455
Lindley and Hutton, Passim
Linnaeus, 363, 364
Linopteris, 86, 109, 113
L. obliqua, 111, 113
Lobelia Rhynchopetalum, 12
Loddiges, C., 368
Lomax, J., 46, 90
Lotsy, J., 86, 117
Lycostrobus, 506
Lyginodendron, 36
L. anomalum, 289
L. Landsburgii, 36, 37
L. oldhamium, 38, 70. See also Lyginopteris oldhamia
L. robustum, 187
L. Sverdrupi, 38
Lyginopterideae, 35–85, 89, 162
Lyginopteris, 35–70, 74–78, 84, 86–94, 98, 109, 186, 189–191, 194,
198, 214, 273, 293, 295, 309, 316, 369
L. lacunosum, 70
L. oldhamia, 38–51, 56, 72
L. tristichum, 70
Lygodium, 88, 180
McBride, T. H., 403
McCoy, Sir F., 240
McLean, R. C., 59
Macropterygium, 554
Macrozamia, 7, 9, 10, 19, 24, 28, 29, 100, 157, 158, 391, 529, 531
M. Denisoni, 16, 28
M. Fraseri, 16, 28, 499
M. gibba, 504
M. heteromera, 19, 27, 33
M. Macleayi, 536
Lignier, O., 34, 63, 217, 229, 247, 386, 415, 428, 432–434, 455
Lindley and Hutton, Passim
Linnaeus, 363, 364
Linopteris, 86, 109, 113
L. obliqua, 111, 113
Lobelia Rhynchopetalum, 12
Loddiges, C., 368
Lomax, J., 46, 90
Lotsy, J., 86, 117
Lycostrobus, 506
Lyginodendron, 36
L. anomalum, 289
L. Landsburgii, 36, 37
L. oldhamium, 38, 70. See also Lyginopteris oldhamia
L. robustum, 187
L. Sverdrupi, 38
Lyginopterideae, 35–85, 89, 162
Lyginopteris, 35–70, 74–78, 84, 86–94, 98, 109, 186, 189–191, 194,
198, 214, 273, 293, 295, 309, 316, 369
L. lacunosum, 70
L. oldhamia, 38–51, 56, 72
L. tristichum, 70
Lygodium, 88, 180
McBride, T. H., 403
McCoy, Sir F., 240
McLean, R. C., 59
Macropterygium, 554
Macrozamia, 7, 9, 10, 19, 24, 28, 29, 100, 157, 158, 391, 529, 531
M. Denisoni, 16, 28
M. Fraseri, 16, 28, 499
M. gibba, 504
M. heteromera, 19, 27, 33
M. Macleayi, 536
Page 721
M. Moorei, 6
M. Preissii, 23
M. spiralis, 19
Malacotesta, 363
M. oblonga, 363
Manoxylic, 7
Mantell, G., 478, 480, 481
Mantellia, 367, 368
M. nidiformis, 367
Marattia, 107
Mariopteris, 111
Marsh, A. S., 385
Masculostrobus, 505
Maslen, A. J., 271
Matonia, 88, 190
Matte, H., 30, 159, 160
Medullosa, 86–110, 119, 144, 149–157, 161, 164, 165, 183, 190, 196,
207, 209, 319
M. anglica, 87–98, 102, 105, 107, 108, 145–158, 161, 180, 219
M. centrofilis, 95–97, 157
M. elegans, 105–107
M. gigas, 100
M. Leuckarti, 87, 102–105, 108, 142–145, 154–159, 165
M. Ludwigii, 163
M. porosa, 89, 92, 157
M. pusilla, 94–96
M. Solmsi, 92, 148, 157
M. Solmsi var. gigantea, 100, 101, 158
M. Solmsi var. lignosa, 92
M. Solmsi var. typica, 101
M. stellata, 87, 89, 96, 97, 100–103, 157, 158, 164
M. stellata var. corticata, 92, 99, 100, 158
M. stellata var. gigantea, 92, 100
M. stellata var. lignosa, 100
M. Preissii, 23
M. spiralis, 19
Malacotesta, 363
M. oblonga, 363
Manoxylic, 7
Mantell, G., 478, 480, 481
Mantellia, 367, 368
M. nidiformis, 367
Marattia, 107
Mariopteris, 111
Marsh, A. S., 385
Masculostrobus, 505
Maslen, A. J., 271
Matonia, 88, 190
Matte, H., 30, 159, 160
Medullosa, 86–110, 119, 144, 149–157, 161, 164, 165, 183, 190, 196,
207, 209, 319
M. anglica, 87–98, 102, 105, 107, 108, 145–158, 161, 180, 219
M. centrofilis, 95–97, 157
M. elegans, 105–107
M. gigas, 100
M. Leuckarti, 87, 102–105, 108, 142–145, 154–159, 165
M. Ludwigii, 163
M. porosa, 89, 92, 157
M. pusilla, 94–96
M. Solmsi, 92, 148, 157
M. Solmsi var. gigantea, 100, 101, 158
M. Solmsi var. lignosa, 92
M. Solmsi var. typica, 101
M. stellata, 87, 89, 96, 97, 100–103, 157, 158, 164
M. stellata var. corticata, 92, 99, 100, 158
M. stellata var. gigantea, 92, 100
M. stellata var. lignosa, 100
Page 722
M. stellata var. typica, 97–99
Medulloseae, 86–165
Megadendron saxonicum, 253
Megalorhachis, 204
M. elliptica, 204
Megalospermum, 326
Megaloxylon, 175–180, 182, 183, 198, 297
M. Scotti, 175–180
Mesopitys, 248, 294–296
M. Tchihatcheffi, 293–296, 299
Mesoxylon, 214, 217, 220, 225, 226, 246, 248, 253, 256, 262, 266,
270–276, 294, 295, 299
M. Lomaxi, 274, 275, 297
M. poroxyloides, 274, 275
M. Sutcliffi, 271–274
Metacordaites, 260
M. Rigolloti, 254, 260
Mettenius, G., 30
Microcycas, 6, 7, 10, 19, 23, 30, 62, 162, 163
M. Calocoma, 27
Microspermum, 343, 365
Miller, H. 449, 536, 584
Miquel, F. A. W., 528, 569
Mitrospermum, 307, 333, 336, 345, 346
M. compressum, 314, 338, 345
Mittagia, 63, 64
M. seminiformis, 63
Morière, J., 369, 395, 415
Morris, J., 264, 512, 514, 528
Mougeot, A., 99
Musocarpus, 361
M. difformis, 361
M. prismaticus, 361
Myelopteris, 106, 154
Medulloseae, 86–165
Megadendron saxonicum, 253
Megalorhachis, 204
M. elliptica, 204
Megalospermum, 326
Megaloxylon, 175–180, 182, 183, 198, 297
M. Scotti, 175–180
Mesopitys, 248, 294–296
M. Tchihatcheffi, 293–296, 299
Mesoxylon, 214, 217, 220, 225, 226, 246, 248, 253, 256, 262, 266,
270–276, 294, 295, 299
M. Lomaxi, 274, 275, 297
M. poroxyloides, 274, 275
M. Sutcliffi, 271–274
Metacordaites, 260
M. Rigolloti, 254, 260
Mettenius, G., 30
Microcycas, 6, 7, 10, 19, 23, 30, 62, 162, 163
M. Calocoma, 27
Microspermum, 343, 365
Miller, H. 449, 536, 584
Miquel, F. A. W., 528, 569
Mitrospermum, 307, 333, 336, 345, 346
M. compressum, 314, 338, 345
Mittagia, 63, 64
M. seminiformis, 63
Morière, J., 369, 395, 415
Morris, J., 264, 512, 514, 528
Mougeot, A., 99
Musocarpus, 361
M. difformis, 361
M. prismaticus, 361
Myelopteris, 106, 154
Page 723
Myeloxylon, 89, 93, 96, 99, 105–108, 119, 123, 139, 144, 154, 155,
196,207, 329
M. Landrioti, 93, 102, 105, 108
M. radiatum, 103, 105, 107, 108
M. topekense, 108
Myrica, 262
M. Gale, 61, 318
Naiadea obtusa, 588
Nathorst, A. G., Passim
Nephrolepis Duffi, 543
Neuropterideae, 87
Neuropteridophylla, 86
Neuropteris, 56, 86, 89, 106, 109–112, 115, 117, 126, 130, 139, 342,
357
N. auriculata, 116
N. Carpentieri, 112
N. gigantea, 110–113, 116, 140
N. heterophylla, 110, 111, 113–117
N. obliqua, 115, 116, 124
N. pseudogigantea, 112
N. Schlehani, 116
Neuropterocarpus, 116
N. Kidstoni, 114
Neuropteromedullosa, 156
Neurospermum, 116, 344
Neurotheca, 110
Newberry, J. S., 128, 131, 320, 507, 589
Nilssonia, 511, 512, 548, 549, 551, 555, 566–578
N. bohemica, 576
N. brevis, 567–571
N. compta, 555, 569, 573, 574, 576, 578
N. densinervis, 575
N. elongata, 566
N. Johnstrupi, 575
196,207, 329
M. Landrioti, 93, 102, 105, 108
M. radiatum, 103, 105, 107, 108
M. topekense, 108
Myrica, 262
M. Gale, 61, 318
Naiadea obtusa, 588
Nathorst, A. G., Passim
Nephrolepis Duffi, 543
Neuropterideae, 87
Neuropteridophylla, 86
Neuropteris, 56, 86, 89, 106, 109–112, 115, 117, 126, 130, 139, 342,
357
N. auriculata, 116
N. Carpentieri, 112
N. gigantea, 110–113, 116, 140
N. heterophylla, 110, 111, 113–117
N. obliqua, 115, 116, 124
N. pseudogigantea, 112
N. Schlehani, 116
Neuropterocarpus, 116
N. Kidstoni, 114
Neuropteromedullosa, 156
Neurospermum, 116, 344
Neurotheca, 110
Newberry, J. S., 128, 131, 320, 507, 589
Nilssonia, 511, 512, 548, 549, 551, 555, 566–578
N. bohemica, 576
N. brevis, 567–571
N. compta, 555, 569, 573, 574, 576, 578
N. densinervis, 575
N. elongata, 566
N. Johnstrupi, 575
Page 724
N. mediana, 551
N. nipponensis, 574
N. orientalis, 568, 572, 575, 576
N. ozvana, 576
N. polymorpha, 567–573
N. princeps, 576, 577
N. pterophylloides, 367, 567, 572, 573
N. rajmahalensis, 571
N. saighensis, 570
N. Schaumburgensis, 578
N. Schmidti, 574
N. Sturii, 576
N. taeniopteroides, 575
N. tenuicaulis, 556, 576
N. tenuinervis, 569, 575
Nilssoniales, 511, 566–587
Nilssoniopteris, 569
Niponophyllum, 282, 283
N. cordaitiforme, 282
Noeggerathia, 589, 590
N. crassa, 227
N. cyclopteroides, 132
N. foliosa, 588
N. Goepperti, 132
N. palmaeformis, 235, 238
Noeggerathianthus, 264
Noeggerathiopsis, 220, 238–243
N. Hislopi, 238, 241, 276, 277. See also Cordaites (Noeggerathiopsis)
Hislopi,
Odontopteris, 86, 106, 109
Oldham and Morris, 443, 488, 514, 561, 572, 574, 576, 577
Oliver, F. W., 55, 61–64, 79, 119, 122, 301, 306–309, 321–326, 329
Oliver and Salisbury, 308, 313, 317
Oliver and Scott, 56, 60
N. nipponensis, 574
N. orientalis, 568, 572, 575, 576
N. ozvana, 576
N. polymorpha, 567–573
N. princeps, 576, 577
N. pterophylloides, 367, 567, 572, 573
N. rajmahalensis, 571
N. saighensis, 570
N. Schaumburgensis, 578
N. Schmidti, 574
N. Sturii, 576
N. taeniopteroides, 575
N. tenuicaulis, 556, 576
N. tenuinervis, 569, 575
Nilssoniales, 511, 566–587
Nilssoniopteris, 569
Niponophyllum, 282, 283
N. cordaitiforme, 282
Noeggerathia, 589, 590
N. crassa, 227
N. cyclopteroides, 132
N. foliosa, 588
N. Goepperti, 132
N. palmaeformis, 235, 238
Noeggerathianthus, 264
Noeggerathiopsis, 220, 238–243
N. Hislopi, 238, 241, 276, 277. See also Cordaites (Noeggerathiopsis)
Hislopi,
Odontopteris, 86, 106, 109
Oldham and Morris, 443, 488, 514, 561, 572, 574, 576, 577
Oliver, F. W., 55, 61–64, 79, 119, 122, 301, 306–309, 321–326, 329
Oliver and Salisbury, 308, 313, 317
Oliver and Scott, 56, 60
Page 725
Oreodoxites Martianus, 338
Osborne, T. G. B., 261, 262
Otopteris mediana, 541
O. tenuata, 543
Otozamites, 460, 467, 500, 511, 514, 517, 521, 522, 528, 530, 537–
545, 546, 587, 589
O. abbreviatus, 521, 522
O. angustatus, 514–516
O. Beani, 541–544, 587, 588
O. Bechei, 538–541, 544
O. bengalensis, 542
O. bengalensis var. obtusa, 543
O. brevifolius, 447
O. Bucklandi, 541
O. Bunburyanus, 542, 543
O. contiguus, 543
O. decorus, 544
O. distans, 515
O. Feistmanteli, 539, 543
O. giganteus, 544
O. Goeppertianus, 483, 538, 544
O. gracilis, 515, 516
O. graphicus, 540
O. groenlandica, 537
O. Hennocquei, 540
O. Hislopi, 515, 516, 521, 522
O. indosinensis, 541
O. Izuimensis, 544
O. Klipsteini, 530, 543, 544
O. lagotis, 544
O. linearis, 541, 544
O. molianus, 541
O. obtusus, 537–541
O. obtusus var. ooliticus, 540
Osborne, T. G. B., 261, 262
Otopteris mediana, 541
O. tenuata, 543
Otozamites, 460, 467, 500, 511, 514, 517, 521, 522, 528, 530, 537–
545, 546, 587, 589
O. abbreviatus, 521, 522
O. angustatus, 514–516
O. Beani, 541–544, 587, 588
O. Bechei, 538–541, 544
O. bengalensis, 542
O. bengalensis var. obtusa, 543
O. brevifolius, 447
O. Bucklandi, 541
O. Bunburyanus, 542, 543
O. contiguus, 543
O. decorus, 544
O. distans, 515
O. Feistmanteli, 539, 543
O. giganteus, 544
O. Goeppertianus, 483, 538, 544
O. gracilis, 515, 516
O. graphicus, 540
O. groenlandica, 537
O. Hennocquei, 540
O. Hislopi, 515, 516, 521, 522
O. indosinensis, 541
O. Izuimensis, 544
O. Klipsteini, 530, 543, 544
O. lagotis, 544
O. linearis, 541, 544
O. molianus, 541
O. obtusus, 537–541
O. obtusus var. ooliticus, 540
Page 726
O. oregonensis, 544
O. Polakii, 541
O. tenuissimus, 543
O. Terquemi, 540
O. vicetinus, 540
Ottokaria, 124, 139–141
O. bengalensis, 116, 139, 140
Pachytesta, 90, 115–117, 144, 304, 319, 323–236
P. gigantea, 323, 325
P. incrassata, 324, 325
Palaeanthus problematica, 461
Palaeopitys, 210
P. Milleri, 210
Palaeospathe aroidea, 132
Palaeoxylon, 100, 289
Palaeoxyris, 477
P. microrhombea, 477
Palaeozamia, 442, 443, 513, 514
P. acutifolia, 514
P. affinis, 514, 515
P. bengalensis, 514
P. cutchensis, 514, 515
P. longifolia, 281
P. pecten, 421
P. recta, 534
P. rigida, 514, 515
P. Rubidgei, 585
Palmacites, 118
Parapitys, 294, 295
P. Spenceri, 294, 295
Parkinson, J., 367
Paullinia, 88
Pearson, H. H. W., 28, 402
O. Polakii, 541
O. tenuissimus, 543
O. Terquemi, 540
O. vicetinus, 540
Ottokaria, 124, 139–141
O. bengalensis, 116, 139, 140
Pachytesta, 90, 115–117, 144, 304, 319, 323–236
P. gigantea, 323, 325
P. incrassata, 324, 325
Palaeanthus problematica, 461
Palaeopitys, 210
P. Milleri, 210
Palaeospathe aroidea, 132
Palaeoxylon, 100, 289
Palaeoxyris, 477
P. microrhombea, 477
Palaeozamia, 442, 443, 513, 514
P. acutifolia, 514
P. affinis, 514, 515
P. bengalensis, 514
P. cutchensis, 514, 515
P. longifolia, 281
P. pecten, 421
P. recta, 534
P. rigida, 514, 515
P. Rubidgei, 585
Palmacites, 118
Parapitys, 294, 295
P. Spenceri, 294, 295
Parkinson, J., 367
Paullinia, 88
Pearson, H. H. W., 28, 402
Page 727
Pecopteris Pluckeneti, 166–168, 171, 308
P. Sterzeli, 168
Pecopteromedullosa, 156
Pelourdea, 277–281
P. hadroclada, 280
P. Imhofi, 280
P. keuperiana, 280
P. megaphylla, 281
P. mirabilis, 281
P. vogesiaca, 278, 279, 281
Penhallow, D. P., 108, 251
Phillips, J., 281, 520, 522, 558, 578
Phoenicopsis, 236, 278, 280
Phylladoderma, 244
P. Arberi, 244
Phyllocladus, 122
Phyllotaenia, 280
P. hadroclada, 280
P. longifolia, 280
Physostoma, 62, 64, 125, 304, 309–316, 326, 329, 359
P. elegans, 62, 309, 311, 314
Pilularia, 58, 64, 327
Pinites, 35
P. Brandlingii, 254
P. Goepperti, 210
P. medullaris, 289
P. Withami, 289
Pissadendron, 285
Pitcairnia, 264
Pityeae, 285–299
Pityoxylon chasense, 251
Pitys, 183, 285–289, 290
P. antiqua, 285–291
P. Dayii, 288
P. Sterzeli, 168
Pecopteromedullosa, 156
Pelourdea, 277–281
P. hadroclada, 280
P. Imhofi, 280
P. keuperiana, 280
P. megaphylla, 281
P. mirabilis, 281
P. vogesiaca, 278, 279, 281
Penhallow, D. P., 108, 251
Phillips, J., 281, 520, 522, 558, 578
Phoenicopsis, 236, 278, 280
Phylladoderma, 244
P. Arberi, 244
Phyllocladus, 122
Phyllotaenia, 280
P. hadroclada, 280
P. longifolia, 280
Physostoma, 62, 64, 125, 304, 309–316, 326, 329, 359
P. elegans, 62, 309, 311, 314
Pilularia, 58, 64, 327
Pinites, 35
P. Brandlingii, 254
P. Goepperti, 210
P. medullaris, 289
P. Withami, 289
Pissadendron, 285
Pitcairnia, 264
Pityeae, 285–299
Pityoxylon chasense, 251
Pitys, 183, 285–289, 290
P. antiqua, 285–291
P. Dayii, 288
Page 728
P. primaeva, 287–289
P. Withami, 286, 289
Plagiozamites, 530, 589, 590
P. carbonarius, 590
P. Planchardi, 509, 589, 590
Platylepis, 369, 415, 478
P. micromyela, 479
Platypterygium, 586
P. Balli, 555, 556
P. densinerve, 575
P. Rogersianum, 576
Platyspermum, 114, 343, 362, 363
P. sulcatum, 362
Poa-Cordaites, 224, 227, 236, 280, 283
P. tenuifolius, 236
Podocarpus, 61, 262
Podocarya, 386, 449
Podozamites, 281, 529, 588
P. Milleri, 536
P. Zitteli, 530
Polylophospermum, 319, 322, 329, 330
P. stephanense, 322, 329
Polypodioides pecteniformis, 522, 523
Polypodium heracleum, 145, 190
P. irioides, 566
P. quercifolium, 145, 190
Polypterocarpus, 357, 358, 361
P. anglicus, 321, 324, 357
Polypterospermum, 319, 323
P. Renaulti, 322, 323
Pomel, A., 368, 497, 500, 529, 541
Poroxyleae, 214–219
Poroxylon, 83, 142, 214–219, 226, 262, 270, 275, 276, 295, 343
P. Boysseti, 214, 218, 219
P. Withami, 286, 289
Plagiozamites, 530, 589, 590
P. carbonarius, 590
P. Planchardi, 509, 589, 590
Platylepis, 369, 415, 478
P. micromyela, 479
Platypterygium, 586
P. Balli, 555, 556
P. densinerve, 575
P. Rogersianum, 576
Platyspermum, 114, 343, 362, 363
P. sulcatum, 362
Poa-Cordaites, 224, 227, 236, 280, 283
P. tenuifolius, 236
Podocarpus, 61, 262
Podocarya, 386, 449
Podozamites, 281, 529, 588
P. Milleri, 536
P. Zitteli, 530
Polylophospermum, 319, 322, 329, 330
P. stephanense, 322, 329
Polypodioides pecteniformis, 522, 523
Polypodium heracleum, 145, 190
P. irioides, 566
P. quercifolium, 145, 190
Polypterocarpus, 357, 358, 361
P. anglicus, 321, 324, 357
Polypterospermum, 319, 323
P. Renaulti, 322, 323
Pomel, A., 368, 497, 500, 529, 541
Poroxyleae, 214–219
Poroxylon, 83, 142, 214–219, 226, 262, 270, 275, 276, 295, 343
P. Boysseti, 214, 218, 219
Page 729
P. Duchartrei, 214
P. Edwardsii, 216–219
P. stephanense, 217, 219
Potonié, H., 38, 111, 112, 166, 249, 549, 590
Potoniea, 113, 116, 117, 128, 129
P. adiantiformis, 111, 112, 131
Prankerd, T. L., 62, 63
Priestley, R., 296
Primula auricula, 91
Protocycadaceae, 161
Protopityeae, 210–213
Protopitys, 207, 209–213, 255
P. Buchiana, 210–213
Psaronius, 88, 168, 253
Pseudoctenis, 528, 556, 584–587
P. Balli, 586
P. crassinervis, 585
P. eathiensis, 584, 585
P. ensiformis, 585
P. Lanei, 586
Pseudocycas, 14, 511, 558–565
P. insignis, 560, 562, 565
P. Roemeri, 560, 564
P. Saportae, 560, 563, 564
P. Steenstrupi, 560, 561, 563
Psygmophyllum, 276
P. Delvali, 235
P. flabellatum, 238
P. majus, 235
Pteridotheca Butterworthi, 54
Pterispermostrobus, 66, 67, 126
P. bifurcates, 65, 66, 126
Pterophyllum, 511, 548–558
P. aequale, 556
P. Edwardsii, 216–219
P. stephanense, 217, 219
Potonié, H., 38, 111, 112, 166, 249, 549, 590
Potoniea, 113, 116, 117, 128, 129
P. adiantiformis, 111, 112, 131
Prankerd, T. L., 62, 63
Priestley, R., 296
Primula auricula, 91
Protocycadaceae, 161
Protopityeae, 210–213
Protopitys, 207, 209–213, 255
P. Buchiana, 210–213
Psaronius, 88, 168, 253
Pseudoctenis, 528, 556, 584–587
P. Balli, 586
P. crassinervis, 585
P. eathiensis, 584, 585
P. ensiformis, 585
P. Lanei, 586
Pseudocycas, 14, 511, 558–565
P. insignis, 560, 562, 565
P. Roemeri, 560, 564
P. Saportae, 560, 563, 564
P. Steenstrupi, 560, 561, 563
Psygmophyllum, 276
P. Delvali, 235
P. flabellatum, 238
P. majus, 235
Pteridotheca Butterworthi, 54
Pterispermostrobus, 66, 67, 126
P. bifurcates, 65, 66, 126
Pterophyllum, 511, 548–558
P. aequale, 556
Page 730
P. angustifolium, 576
P. Bavieri, 555
P. blechnoides, 509, 552
P. Braunianum, 554, 556, 558
P. Bronni, 553, 554
P. Buchianum, 529
P. Cambryi, 509, 552
P. Carterianum, 586
P. concinnum, 549
P. Cottaeanum, 509, 552
P. crassinerve, 550
P. distans, 557
P. Dunkerianum, 527, 528, 557
P. Fayoli, 509, 551, 552
P. Footeanum, 557
P. Goeppertianum, 544
P. gonorrachis, 509
P. Grand’Euryanum, 509, 552
P. inconstans, 555
P. inflexum, 509
P. Jaegeri, 548–550, 553
P. longifolium, 553
P. Lyellianum, 557, 558
P. majus, 548
P. marginatum, 550
P. medianum, 576
P. minus, 548
P. Morrisianum, 578, 586
P. Nathorsti, 556
P. Nilssoni, 551, 557, 558
P. oblongifolium, 530
P. pecten, 512, 517
P. princeps, 573, 576, 586
P. rigidum, 523
P. Bavieri, 555
P. blechnoides, 509, 552
P. Braunianum, 554, 556, 558
P. Bronni, 553, 554
P. Buchianum, 529
P. Cambryi, 509, 552
P. Carterianum, 586
P. concinnum, 549
P. Cottaeanum, 509, 552
P. crassinerve, 550
P. distans, 557
P. Dunkerianum, 527, 528, 557
P. Fayoli, 509, 551, 552
P. Footeanum, 557
P. Goeppertianum, 544
P. gonorrachis, 509
P. Grand’Euryanum, 509, 552
P. inconstans, 555
P. inflexum, 509
P. Jaegeri, 548–550, 553
P. longifolium, 553
P. Lyellianum, 557, 558
P. majus, 548
P. marginatum, 550
P. medianum, 576
P. minus, 548
P. Morrisianum, 578, 586
P. Nathorsti, 556
P. Nilssoni, 551, 557, 558
P. oblongifolium, 530
P. pecten, 512, 517
P. princeps, 573, 576, 586
P. rigidum, 523
Page 731
P. Rogersianum, 554, 575
P. saxonicum, 537
P. Schaumburgense, 578
P. Schenki, 555
P. Tietzei, 554, 555
P. Williamsonis, 573
Pterospermum, 343, 357
P. anglicum, 357
Pterozamites, 529
Ptilophyllum, 379, 512–529, 539
P. acutifolium, 446, 517, 521, 522
P. acutifolium var. maximum, 515
P. Anderssoni, 525, 527
P. antarcticum, 525, 527
P. boreale, 525–527, 530
P. cutchense, 478, 514–517, 521, 522, 524
P. cutchense var. curvifolium, 515
P. Dunkerianum, 527
P. hirsutum, 520
P. pecten, 437–440, 443, 445, 512–525
Ptilozamites, 511, 512
Ptychotesta, 319, 321, 322, 348
P. pachypterum, 322
P. tenuis, 321, 322
Ptychoxylon, 142, 145, 186–190
P. Levyi, 187–190
Pychnoxylic, 7
Pycnophyllum, 223
Rachiopteris aspera, 47
R. Williamsoni, 154, 155
Raciborski, M., 412, 578, 581, 582
Radiculites reticulatus, 217
Radiospermum, 64
P. saxonicum, 537
P. Schaumburgense, 578
P. Schenki, 555
P. Tietzei, 554, 555
P. Williamsonis, 573
Pterospermum, 343, 357
P. anglicum, 357
Pterozamites, 529
Ptilophyllum, 379, 512–529, 539
P. acutifolium, 446, 517, 521, 522
P. acutifolium var. maximum, 515
P. Anderssoni, 525, 527
P. antarcticum, 525, 527
P. boreale, 525–527, 530
P. cutchense, 478, 514–517, 521, 522, 524
P. cutchense var. curvifolium, 515
P. Dunkerianum, 527
P. hirsutum, 520
P. pecten, 437–440, 443, 445, 512–525
Ptilozamites, 511, 512
Ptychotesta, 319, 321, 322, 348
P. pachypterum, 322
P. tenuis, 321, 322
Ptychoxylon, 142, 145, 186–190
P. Levyi, 187–190
Pychnoxylic, 7
Pycnophyllum, 223
Rachiopteris aspera, 47
R. Williamsoni, 154, 155
Raciborski, M., 412, 578, 581, 582
Radiculites reticulatus, 217
Radiospermum, 64
Page 732
R. ornatum, 323
Rattray, C., 28
Raumeria, 409
R. Reichenbachiana, 384, 385
R. Schulziana, 412
Reichenbach, —, 253
Reid, Mr and Mrs Clement, 300
Renault, B., Passim
Renier, A., 116
Retinodendron, 181
Rhabdocarpos Mansfieldi, 326
Rhabdocarpus, 90, 115, 116, 215, 333, 341–344, 362, 364
R. Boschianus, 320
R. elongatus, 174
R. Lilleanus, 342
R. Mansfieldi, 326
R. multistriatus, 362, 363
R. Oliveri, 344
R. orientalis, 174
R. ovoides, 354
R. subtunicatus, 115, 342
R. tunicatus, 115, 341, 342, 362
Rhabdospermum, 116, 307, 333, 335, 339–344, 347
R. cyclocaryon, 340, 344
Rhetinangium, 85, 181–183
R. Arberi, 181–183
Rhexoxylon, 87, 101, 146–149, 207
R. africanum, 146–149
Rhipidopsis ginkgoides, 140
Rhiptozamites Goepperti, 238, 244, 245
Rhizo-Cordaites, 224, 237
Rhizophidium, 62
Rhynchogonium, 358–363
R. costatum, 358, 359
Rattray, C., 28
Raumeria, 409
R. Reichenbachiana, 384, 385
R. Schulziana, 412
Reichenbach, —, 253
Reid, Mr and Mrs Clement, 300
Renault, B., Passim
Renier, A., 116
Retinodendron, 181
Rhabdocarpos Mansfieldi, 326
Rhabdocarpus, 90, 115, 116, 215, 333, 341–344, 362, 364
R. Boschianus, 320
R. elongatus, 174
R. Lilleanus, 342
R. Mansfieldi, 326
R. multistriatus, 362, 363
R. Oliveri, 344
R. orientalis, 174
R. ovoides, 354
R. subtunicatus, 115, 342
R. tunicatus, 115, 341, 342, 362
Rhabdospermum, 116, 307, 333, 335, 339–344, 347
R. cyclocaryon, 340, 344
Rhetinangium, 85, 181–183
R. Arberi, 181–183
Rhexoxylon, 87, 101, 146–149, 207
R. africanum, 146–149
Rhipidopsis ginkgoides, 140
Rhiptozamites Goepperti, 238, 244, 245
Rhizo-Cordaites, 224, 237
Rhizophidium, 62
Rhynchogonium, 358–363
R. costatum, 358, 359
Page 733
R. sulcatum, 358, 360
Rhynchopetalum montanum, 12
Richards, J. T., 536, 584
Richter, P. B., 200
Roehl, von, 136
Salisbury, E. J., 122, 307, 320
Samaropsis, 168–171, 236, 245, 265–267, 303, 333–338, 345–354
S. acuta, 167–171
S. alata, 351
S. Baileyi, 351
S. barcellosus, 350, 351
S. bicaudata, 348, 350
S. bignonioides, 350
S. Crampii, 349
S. emarginata, 337, 349, 350
S. fluitans, 142, 338, 348, 350
S. indica, 352, 353
S. Leslii, 352, 353
S. marginata, 337
S. Milleri, 353
S. moravica, 349, 352
S. Newberryi, 350
S. Pitcairniae, 266
S. Seixasi, 350, 351
S. spitzbergensis, 360
S. ulmiformis, 336
Saporta, G. de, 368, 369, 422, 429, 434, 449, 477–479, 494, 499, 500,
589
Saporta and Marion, 132, 137, 138, 317, 395, 501, 505
Sarcotaxus, 265
S. angulosus, 347
S. avellana, 346
S. olivaeformis, 347
Schenk, A., 97, 164, 282, 336, 529, 550, 554, 555, 568, 578, 581
Rhynchopetalum montanum, 12
Richards, J. T., 536, 584
Richter, P. B., 200
Roehl, von, 136
Salisbury, E. J., 122, 307, 320
Samaropsis, 168–171, 236, 245, 265–267, 303, 333–338, 345–354
S. acuta, 167–171
S. alata, 351
S. Baileyi, 351
S. barcellosus, 350, 351
S. bicaudata, 348, 350
S. bignonioides, 350
S. Crampii, 349
S. emarginata, 337, 349, 350
S. fluitans, 142, 338, 348, 350
S. indica, 352, 353
S. Leslii, 352, 353
S. marginata, 337
S. Milleri, 353
S. moravica, 349, 352
S. Newberryi, 350
S. Pitcairniae, 266
S. Seixasi, 350, 351
S. spitzbergensis, 360
S. ulmiformis, 336
Saporta, G. de, 368, 369, 422, 429, 434, 449, 477–479, 494, 499, 500,
589
Saporta and Marion, 132, 137, 138, 317, 395, 501, 505
Sarcotaxus, 265
S. angulosus, 347
S. avellana, 346
S. olivaeformis, 347
Schenk, A., 97, 164, 282, 336, 529, 550, 554, 555, 568, 578, 581
Page 734
Schimper, W. P., 127, 477, 500, 501, 505, 530, 554
Schimper and Mougeot, 278
Schizodendron, 250
Schizopodium, 369
S. Renaulti, 369
Schizospermum, 319
Schizoxylon, 200, 203
S. taeniatum, 201
Schlotheim, E. F. von, 166
Schmaulhausen, J., 174, 233, 238, 244, 245
Schuster, J., 411, 412, 477
Schützia, 124–127
S. anomala, 126, 127
S. Bennieana, 127
S. permiensis, 127
Scolopteris, 168
Scott, D. H., Passim
Scott and Jeffrey, 191, 196
Scott and Maslen, 119, 122, 330
Scuto-Cordaites, 237
S. Grand’Euryi, 238
Sellards, E. H., 126
Senecio praecox, 287
Senftenbergia, 63
Sequoia, 217
Serjania, 88
Sewardia latifolia, 589, 591
Shaw, F. J. F., 160
Shirley, J., 255
Sigillaria, 214
Sigillariopsis, 214
Solms-Laubach, Graf zu., Passim
Sorocladus stellata, 110
Sparganum, 93, 105, 184, 191
Schimper and Mougeot, 278
Schizodendron, 250
Schizopodium, 369
S. Renaulti, 369
Schizospermum, 319
Schizoxylon, 200, 203
S. taeniatum, 201
Schlotheim, E. F. von, 166
Schmaulhausen, J., 174, 233, 238, 244, 245
Schuster, J., 411, 412, 477
Schützia, 124–127
S. anomala, 126, 127
S. Bennieana, 127
S. permiensis, 127
Scolopteris, 168
Scott, D. H., Passim
Scott and Jeffrey, 191, 196
Scott and Maslen, 119, 122, 330
Scuto-Cordaites, 237
S. Grand’Euryi, 238
Sellards, E. H., 126
Senecio praecox, 287
Senftenbergia, 63
Sequoia, 217
Serjania, 88
Sewardia latifolia, 589, 591
Shaw, F. J. F., 160
Shirley, J., 255
Sigillaria, 214
Sigillariopsis, 214
Solms-Laubach, Graf zu., Passim
Sorocladus stellata, 110
Sparganum, 93, 105, 184, 191
Page 735
Spencer, J., 294
Sphaereda paradoxa, 502
Sphaerostoma, 71, 78–81, 307, 309, 316, 319
S. ovale, 79, 80, 312, 313
Sphenophyllum, 110
Sphenopteridophylla, 86
Sphenopteris, 109
S. artemisaefolia, 169
S. crithmifolia, 169, 170
S. dissecta, 77, 81
S. Dubuissonis, 56
S. elegans, 72, 75, 77, 78, 81
S. Hoeninghausi, 47–53, 56, 70
S. Linkii, 51
S. obtusifolia, 81
S. obtusiloba, 65
S. refracta, 208
S. Schaumberg-Lippeana, 66
Sphenozamites, 587–589
S. Belli, 588, 589
S. Geinitzianus, 589
S. Geylerianus, 588
S. robustus, 589
S. Rochei, 509, 587
S. Rossii, 588
Sporocarpon ornatum, 309
Stangeria paradoxa, 8, 9, 12, 16, 19–22, 29, 30, 32, 34, 159, 160, 312,
386
Staub, M., 578
Steloxylon, 163–165
S. Ludwigii, 163, 164
Stenomyelon, 182–185
S. tuedianum, 183–185
Stenorrachis, 503
Sphaereda paradoxa, 502
Sphaerostoma, 71, 78–81, 307, 309, 316, 319
S. ovale, 79, 80, 312, 313
Sphenophyllum, 110
Sphenopteridophylla, 86
Sphenopteris, 109
S. artemisaefolia, 169
S. crithmifolia, 169, 170
S. dissecta, 77, 81
S. Dubuissonis, 56
S. elegans, 72, 75, 77, 78, 81
S. Hoeninghausi, 47–53, 56, 70
S. Linkii, 51
S. obtusifolia, 81
S. obtusiloba, 65
S. refracta, 208
S. Schaumberg-Lippeana, 66
Sphenozamites, 587–589
S. Belli, 588, 589
S. Geinitzianus, 589
S. Geylerianus, 588
S. robustus, 589
S. Rochei, 509, 587
S. Rossii, 588
Sporocarpon ornatum, 309
Stangeria paradoxa, 8, 9, 12, 16, 19–22, 29, 30, 32, 34, 159, 160, 312,
386
Staub, M., 578
Steloxylon, 163–165
S. Ludwigii, 163, 164
Stenomyelon, 182–185
S. tuedianum, 183–185
Stenorrachis, 503
Page 736
S. scanicus, 503, 568
Stenzel, G., 165
Stenzelia, 106
Stephanospermum, 302–304, 307, 323, 326–329, 345, 497
S. akenioides, 311, 314, 319, 326–328
S. caryoides, 328, 329
Sternberg, C. von, 118, 362, 487, 522, 555
Sternbergia, 247
Sterzel, J. T., 105, 167, 168
Stigmaria, 193
Stokes and Webb, 480, 481, 491, 497
Stopes, M. C., Passim
Strobilites, 124, 141, 142, 500
S. Milleryensis, 141, 142, 338
Stur, D., 70, 77, 167
Sub-Zamites, 521, 530, 531
Sutcliffe, W. H., 149, 161, 162
Sutcliffia, 87, 149–156, 182–185
S. insignis, 149–156
S. Williamsoni, 154
Syncardia, 200, 205
S. pusilla, 201, 202
Taeniopteris, 1, 86, 511, 568, 576, 583
T. asplenioides, 581
T. vittata, 467, 470, 472, 508, 569
Tate, R., 534
Taxospermum, 265, 333, 346, 347
T. Grüneri, 322, 347
Taxus, 306, 347, 396
Teconia, 46
Telangium, 54, 55, 125
T. Scotti, 54, 311
Thinouia scandens, 88
Stenzel, G., 165
Stenzelia, 106
Stephanospermum, 302–304, 307, 323, 326–329, 345, 497
S. akenioides, 311, 314, 319, 326–328
S. caryoides, 328, 329
Sternberg, C. von, 118, 362, 487, 522, 555
Sternbergia, 247
Sterzel, J. T., 105, 167, 168
Stigmaria, 193
Stokes and Webb, 480, 481, 491, 497
Stopes, M. C., Passim
Strobilites, 124, 141, 142, 500
S. Milleryensis, 141, 142, 338
Stur, D., 70, 77, 167
Sub-Zamites, 521, 530, 531
Sutcliffe, W. H., 149, 161, 162
Sutcliffia, 87, 149–156, 182–185
S. insignis, 149–156
S. Williamsoni, 154
Syncardia, 200, 205
S. pusilla, 201, 202
Taeniopteris, 1, 86, 511, 568, 576, 583
T. asplenioides, 581
T. vittata, 467, 470, 472, 508, 569
Tate, R., 534
Taxospermum, 265, 333, 346, 347
T. Grüneri, 322, 347
Taxus, 306, 347, 396
Teconia, 46
Telangium, 54, 55, 125
T. Scotti, 54, 311
Thinouia scandens, 88
Page 737
Thiselton-Dyer, W. T., 467
Thlaspi arvense, 303
Thoday, Mrs, 28, 160, 161
Thomas, H. H., Passim
Thomas and Bancroft, 560
Thomson, R. B., 252, 254
Thomson and Allin, 251
Thysanotesta, 304, 364
T. sagittula, 304, 314, 359, 364
Thysopteris elegans, 65
Titanophyllum, 283, 284
T. Brittsi, 284
T. Grand’Euryi, 283, 284
Torreya, 301, 325, 347
Trigonocarpon, 117, 118
Trigonocarpus, 61, 90, 94, 115–123, 162, 301, 303, 307, 316–329,
345, 499
T. actaeonelloides, 354
T. corrugatus, 124
T. Dawesi, 123, 320
T. Moyseyi, 122
T. multicarinatus, 320
T. olivaeformis, 119
T. Oliveri, 122
T. Parkinsoni, 118–123, 319–321, 329
T. pusillus, 122, 319, 320
T. rostratum, 321
T. schizocarpoides, 319
T. shorensis, 121–124, 319, 320
T. sporites, 320
Trigonocarpum gloagianum, 358, 360
Tripterospermum, 119, 321, 358, 369
T. ellipticum, 321, 357
Tsuga, 127, 315
Thlaspi arvense, 303
Thoday, Mrs, 28, 160, 161
Thomas, H. H., Passim
Thomas and Bancroft, 560
Thomson, R. B., 252, 254
Thomson and Allin, 251
Thysanotesta, 304, 364
T. sagittula, 304, 314, 359, 364
Thysopteris elegans, 65
Titanophyllum, 283, 284
T. Brittsi, 284
T. Grand’Euryi, 283, 284
Torreya, 301, 325, 347
Trigonocarpon, 117, 118
Trigonocarpus, 61, 90, 94, 115–123, 162, 301, 303, 307, 316–329,
345, 499
T. actaeonelloides, 354
T. corrugatus, 124
T. Dawesi, 123, 320
T. Moyseyi, 122
T. multicarinatus, 320
T. olivaeformis, 119
T. Oliveri, 122
T. Parkinsoni, 118–123, 319–321, 329
T. pusillus, 122, 319, 320
T. rostratum, 321
T. schizocarpoides, 319
T. shorensis, 121–124, 319, 320
T. sporites, 320
Trigonocarpum gloagianum, 358, 360
Tripterospermum, 119, 321, 358, 369
T. ellipticum, 321, 357
Tsuga, 127, 315
Page 738
Tylodendron, 250, 253, 491
Tyson, P., 385
Tysonia marylandica, 385
Ullmannites Beinertianus, 199
Ulospermum, 497
Unger, F., 190, 194, 196, 200, 201, 203, 204, 285, 449
Vectia, 419, 420
V. luccombensis, 419
Velenovský, J., 281, 504, 505
Völkelia, 208–210
V. refracta, 208, 209
Vries, H. de, 10
Walch, J. E. J., 497
Walchia, 253, 338
Ward, L. F., 368, 369, 385, 409, 417, 491, 497, 582
Wardia, 172–174
W. fertilis, 171, 172
Warming, E., 25
Warren, E., 256
Watson, D. M. S., 68
Weber and Sterzel, 97, 99, 101, 104, 108
Weiss, C. E., 264, 338
Weiss, F. E., 54, 68
Welsford, E. J., 61
Weltrichia, 475–477
W. Fabrei, 477
W. mirabilis, 476
W. oolithica, 477
Welwitschia, 160, 161, 336, 380, 403
Wettstein, R. V., 403
White, D., 169, 172, 173, 192, 243, 255, 258, 284, 326
Whittleseya, 124–131
Tyson, P., 385
Tysonia marylandica, 385
Ullmannites Beinertianus, 199
Ulospermum, 497
Unger, F., 190, 194, 196, 200, 201, 203, 204, 285, 449
Vectia, 419, 420
V. luccombensis, 419
Velenovský, J., 281, 504, 505
Völkelia, 208–210
V. refracta, 208, 209
Vries, H. de, 10
Walch, J. E. J., 497
Walchia, 253, 338
Ward, L. F., 368, 369, 385, 409, 417, 491, 497, 582
Wardia, 172–174
W. fertilis, 171, 172
Warming, E., 25
Warren, E., 256
Watson, D. M. S., 68
Weber and Sterzel, 97, 99, 101, 104, 108
Weiss, C. E., 264, 338
Weiss, F. E., 54, 68
Welsford, E. J., 61
Weltrichia, 475–477
W. Fabrei, 477
W. mirabilis, 476
W. oolithica, 477
Welwitschia, 160, 161, 336, 380, 403
Wettstein, R. V., 403
White, D., 169, 172, 173, 192, 243, 255, 258, 284, 326
Whittleseya, 124–131
Page 739
W. brevifolia, 128
W. concinna, 131
W. elegans, 128–131
W. fertilis, 129, 130
W. integrifolia, 131
W. undulata, 131
Wieland, G. R., Passim
Wielandia, 463
Wielandiella, 454, 463–467, 472, 473, 478, 481, 550
W. angustifolia, 464, 466, 467, 470
W. punctata, 446
Wild, G., 119
Williamson, W. C., Passim
Williamson and Scott, 42–46, 67, 69, 74, 75, 77
Williamsonia, 372, 386, 409, 412, 421–463, 494, 516, 517, 520, 524,
531–534, 538, 546
W. angustifolia, 463
W. Bibbinsi, 462
W. bituberculata, 457
W. Blandfordi, 445, 446, 517
W. Bucklandi, 386, 448, 449
W. Carruthersi, 439, 447, 448
W. cretacea, 461, 462
W. Cuauhtemoc, 446
W. elongata, 462
W. Forchammeri, 461
W. gallinacea, 462
W. gigas, 421–436, 443–447, 451, 457, 460, 472, 483
W. hastula, 422
W. Haydeni, 460
W. indica, 446
W. Leckenbyi, 439, 440, 448, 473
W. Lignieri, 472
W. mexicana, 459, 460
W. concinna, 131
W. elegans, 128–131
W. fertilis, 129, 130
W. integrifolia, 131
W. undulata, 131
Wieland, G. R., Passim
Wielandia, 463
Wielandiella, 454, 463–467, 472, 473, 478, 481, 550
W. angustifolia, 464, 466, 467, 470
W. punctata, 446
Wild, G., 119
Williamson, W. C., Passim
Williamson and Scott, 42–46, 67, 69, 74, 75, 77
Williamsonia, 372, 386, 409, 412, 421–463, 494, 516, 517, 520, 524,
531–534, 538, 546
W. angustifolia, 463
W. Bibbinsi, 462
W. bituberculata, 457
W. Blandfordi, 445, 446, 517
W. Bucklandi, 386, 448, 449
W. Carruthersi, 439, 447, 448
W. cretacea, 461, 462
W. Cuauhtemoc, 446
W. elongata, 462
W. Forchammeri, 461
W. gallinacea, 462
W. gigas, 421–436, 443–447, 451, 457, 460, 472, 483
W. hastula, 422
W. Haydeni, 460
W. indica, 446
W. Leckenbyi, 439, 440, 448, 473
W. Lignieri, 472
W. mexicana, 459, 460
Page 740
W. microps, 445
W. minima, 461
W. Morieri, 395
W. oregonensis, 461
W. Otozamitis, 460
W. pecten, 422, 426, 440–442, 445, 456
W. phoenicopsoides, 462
W. problematica, 461, 462
W. pyramidalis, 457
W. recentior, 463
W. Riesii, 461
W. scotica, 374, 391, 396, 403, 415, 440, 447, 449–456, 465, 478, 489
W. setosa, 436, 443–445
W. Smockii, 461
Williamsonia sp., 443–446, 460
W. spectabilis, 435–442, 457, 445, 459, 460, 473, 476
W. virginiensis, 462
W. whitbiensis, 435, 438–442, 457, 458, 460
Williamsoniella, 434, 454, 467–473
W. coronata, 467–472
W. Lignieri, 472
Wills, L. T., 278
Witham, H., 35, 254, 285, 289
Worsdell, W. C., 30, 33, 34, 46, 155, 159, 160, 162, 403
Xenoxylon phyllocladoides, 213
Yabe, H., 578
Yates, J., 421
Yatesia, 386, 478
Y. crassa, 483
Y. gracilis, 483
Y. Joassiana, 483
Y. Morrisii, 484
Y. vogesiacus, 277, 278, 483
W. minima, 461
W. Morieri, 395
W. oregonensis, 461
W. Otozamitis, 460
W. pecten, 422, 426, 440–442, 445, 456
W. phoenicopsoides, 462
W. problematica, 461, 462
W. pyramidalis, 457
W. recentior, 463
W. Riesii, 461
W. scotica, 374, 391, 396, 403, 415, 440, 447, 449–456, 465, 478, 489
W. setosa, 436, 443–445
W. Smockii, 461
Williamsonia sp., 443–446, 460
W. spectabilis, 435–442, 457, 445, 459, 460, 473, 476
W. virginiensis, 462
W. whitbiensis, 435, 438–442, 457, 458, 460
Williamsoniella, 434, 454, 467–473
W. coronata, 467–472
W. Lignieri, 472
Wills, L. T., 278
Witham, H., 35, 254, 285, 289
Worsdell, W. C., 30, 33, 34, 46, 155, 159, 160, 162, 403
Xenoxylon phyllocladoides, 213
Yabe, H., 578
Yates, J., 421
Yatesia, 386, 478
Y. crassa, 483
Y. gracilis, 483
Y. Joassiana, 483
Y. Morrisii, 484
Y. vogesiacus, 277, 278, 483
Page 741
Y. Yatesii, 484
Yokoyama, M., 537, 578, 582
Young, G., 421
Young, J., 358
Yucca, 277
Yuccites, 277, 278
Y. Schimperianus, 281
Zalessky, M., 70, 191, 194, 197, 198, 238, 243, 244, 291–295, 358,
359, 590
Zalesskya gracilis, 180
Zamia, 11, 12, 16, 24, 30, 62, 139, 507
Z. angustifolia, 16
Z. Brongniarti, 395
Z. crassa, 504
Z. floridana, 16, 24, 25
Z. furfuracea, 19
Z. gigas, 421
Z. Goldiei, 522
Z. integrifolia, 16, 76
Z. linifolia, 16
Z. Loddigesii, 5, 16, 18
Z. macrocephala, 503
Z. muricata, 587
Z. pectinata, 522
Z. praecedens, 510
Z. pseudoparasitica, 19
Z. pumila, 9
Z. pygmaea, 4
Z. Skinneri, 587
Z. Wallisii, 16, 17
Zamieae, 8
Zamiophyllum, 529–531
Zamiopsis, 512
Zamiostrobus, 496, 503
Yokoyama, M., 537, 578, 582
Young, G., 421
Young, J., 358
Yucca, 277
Yuccites, 277, 278
Y. Schimperianus, 281
Zalessky, M., 70, 191, 194, 197, 198, 238, 243, 244, 291–295, 358,
359, 590
Zalesskya gracilis, 180
Zamia, 11, 12, 16, 24, 30, 62, 139, 507
Z. angustifolia, 16
Z. Brongniarti, 395
Z. crassa, 504
Z. floridana, 16, 24, 25
Z. furfuracea, 19
Z. gigas, 421
Z. Goldiei, 522
Z. integrifolia, 16, 76
Z. linifolia, 16
Z. Loddigesii, 5, 16, 18
Z. macrocephala, 503
Z. muricata, 587
Z. pectinata, 522
Z. praecedens, 510
Z. pseudoparasitica, 19
Z. pumila, 9
Z. pygmaea, 4
Z. Skinneri, 587
Z. Wallisii, 16, 17
Zamieae, 8
Zamiophyllum, 529–531
Zamiopsis, 512
Zamiostrobus, 496, 503
Page 742
Z. Loppineti, 504
Z. orientalis, 504
Z. Saportana, 505
Zamites, 281, 378, 379, 507, 512, 517, 520, 521, 525, 527, 529–537,
589, 590
Z. Anderssoni, 521
Z. antarcticus, 521, 527
Z. bohemicus, 534
Z. borealis, 521, 525, 530, 531
Z. brevipennis, 521, 525
Z. Buchianus, 531, 535–537
Z. carbonarius, 590
Z. Carruthersi, 535, 536
Z. claravallensis, 534
Z. eathiensis, 584
Z. epibius, 510
Z. familiaris, 505
Z. Feneonis, 533
Z. gigas, 422–426, 443, 510, 521, 530–534
Z. iburgensis, 534
Z. Mantelli, 532
Z. Moreaui, 533
Z. palaeocenicus, 510
Z. pusillus, 521
Z. recta, 534
Z. Renevieri, 533
Z. Schmiedelii, 534
Zamites sp., 585
Z. speciosus, 521, 525
Z. truncatus, 532
Z. Zitteli, 535
Zeiller, R., Passim
Zigno, A. de, 281, 460, 587, 588
Zopf, W., 62, 538
Z. orientalis, 504
Z. Saportana, 505
Zamites, 281, 378, 379, 507, 512, 517, 520, 521, 525, 527, 529–537,
589, 590
Z. Anderssoni, 521
Z. antarcticus, 521, 527
Z. bohemicus, 534
Z. borealis, 521, 525, 530, 531
Z. brevipennis, 521, 525
Z. Buchianus, 531, 535–537
Z. carbonarius, 590
Z. Carruthersi, 535, 536
Z. claravallensis, 534
Z. eathiensis, 584
Z. epibius, 510
Z. familiaris, 505
Z. Feneonis, 533
Z. gigas, 422–426, 443, 510, 521, 530–534
Z. iburgensis, 534
Z. Mantelli, 532
Z. Moreaui, 533
Z. palaeocenicus, 510
Z. pusillus, 521
Z. recta, 534
Z. Renevieri, 533
Z. Schmiedelii, 534
Zamites sp., 585
Z. speciosus, 521, 525
Z. truncatus, 532
Z. Zitteli, 535
Zeiller, R., Passim
Zigno, A. de, 281, 460, 587, 588
Zopf, W., 62, 538
Page 743
FOOTNOTES:
[1] Wieland (06) p. 190.
[2] Botanical Magazine, Tab. 1741.
[3] Matte (04) Pl. xi. fig. 185 (Microcycas).
[4] Thibout (96).
[5] Thibout (96) Pl. iv. fig. 3. A branched microstrobilus of a Macrozamia is exhibited in
the Botanical Department of the British Museum.
[6] Pearson (06).
[7] Sohns-Laubach (90); South and Compton (08); Smith, F. G. (07).
[8] Chamberlain (13).
[9] Lang (97); (00).
[10] Chamberlain (09) p. 410.
[11] Caldwell (07).
[12] For figures and references, see Coulter and Chamberlain (10).
[13] Chamberlain (12) p. 11.
[14] Saxton (104).
[15] For an explanation of the occurrence of a single cotyledon in Ceratozamia, see
Dorety (08).
[16] Worsdell (00); (01); Chamberlain (11).
[17] μανός, porous, loose in texture; πυκνόϛ, compact.
[18] Sifton (15).
[19] Worsdell (00); (06). See postea, Chap. xxx.
[20] Worsdell (982).
[21] For figures, see Mettenius (60) B.; de Bary (84) A.; le Goc (14); Marsh (14).
[22] Wieland (06) pp. 62, 63.
[23] Matte (04) Pl. vii. fig. 111.
[24] Scott (97); Matte (04) p. 164.
[25] The species Cycas taiwanensis was founded by Mr Carruthers (93) on material from
Formosa, and C. revoluta has also been recorded from Formosa [Thiselton-Dyer (02) p.
559], but according to Mr Elwes it is very doubtful whether any native Cycad occurs on
the island.
[26] Engler (95) p. 92; Stapf (14).
[27] Gard. Chron. June 11, 1904, p. 370.
[28] Bot. Mag. 1909, Tab. 8232.
[1] Wieland (06) p. 190.
[2] Botanical Magazine, Tab. 1741.
[3] Matte (04) Pl. xi. fig. 185 (Microcycas).
[4] Thibout (96).
[5] Thibout (96) Pl. iv. fig. 3. A branched microstrobilus of a Macrozamia is exhibited in
the Botanical Department of the British Museum.
[6] Pearson (06).
[7] Sohns-Laubach (90); South and Compton (08); Smith, F. G. (07).
[8] Chamberlain (13).
[9] Lang (97); (00).
[10] Chamberlain (09) p. 410.
[11] Caldwell (07).
[12] For figures and references, see Coulter and Chamberlain (10).
[13] Chamberlain (12) p. 11.
[14] Saxton (104).
[15] For an explanation of the occurrence of a single cotyledon in Ceratozamia, see
Dorety (08).
[16] Worsdell (00); (01); Chamberlain (11).
[17] μανός, porous, loose in texture; πυκνόϛ, compact.
[18] Sifton (15).
[19] Worsdell (00); (06). See postea, Chap. xxx.
[20] Worsdell (982).
[21] For figures, see Mettenius (60) B.; de Bary (84) A.; le Goc (14); Marsh (14).
[22] Wieland (06) pp. 62, 63.
[23] Matte (04) Pl. vii. fig. 111.
[24] Scott (97); Matte (04) p. 164.
[25] The species Cycas taiwanensis was founded by Mr Carruthers (93) on material from
Formosa, and C. revoluta has also been recorded from Formosa [Thiselton-Dyer (02) p.
559], but according to Mr Elwes it is very doubtful whether any native Cycad occurs on
the island.
[26] Engler (95) p. 92; Stapf (14).
[27] Gard. Chron. June 11, 1904, p. 370.
[28] Bot. Mag. 1909, Tab. 8232.
Page 744
[29] Pearson (06).
[30] Chamberlain (122).
[31] Chamberlain (06).
[32] Webber (01).
[33] Chamberlain (09).
[34] Hooker, J. D. (91) A. p. 98 (footnote).
[35] Pearson (06).
[36] Prof. de Vries kindly informed me in a letter that this estimate is not to be regarded
as anything more than a rough guess.
[37] Stopes (10).
[38] Caldwell (07).
[39] Bower (84).
[40] Rosen (11).
[41] Seward (95) A. pp. 15 et seq.
[42] Braun, A. (75).
[43] Thiselton-Dyer (65) B.; Bot. Mag. 1909, Tab. 8242.
[44] Thiselton-Dyer (02) p. 560.
[45] Gard. Chron. 1904, June 11, p. 370.
[46] Seward (97).
[47] Braun, A. (752) p. 376.
[48] Bot. Mag. 1818, Tab. 1969.
[49] Matte (04) p. 34.
[50] Seward (95) A. p. 5; Robertson (02) fig. 4.
[51] Vol. ii. fig. 287, p. 389.
[52] Chamberlain (09).
[53] Braun, A. (75); Bornemann (56) A. Pl. x.
[54] Caldwell (07); Caldwell and Baker (07).
[55] Bot. Mag. 1859, Tab. 5121.
[56] Vol. ii. p. 485.
[57] Lignier (94).
[58] Chamberlain (123).
[59] For information on the anatomy of reproductive shoots, see Thibout (96); Scott
(97); Worsdell (98); Matte (04).
[60] Thiselton-Dyer (01); Bot. Mag. 1915, Tab. 8592, 8593. For instances of monstrous
cones, see Miquel (69), Wieland (02).
[61] Chamberlain (09).
[62] Dorrien-Smith (11) p. 287.
[63] Stopes (04) p. 467.
[30] Chamberlain (122).
[31] Chamberlain (06).
[32] Webber (01).
[33] Chamberlain (09).
[34] Hooker, J. D. (91) A. p. 98 (footnote).
[35] Pearson (06).
[36] Prof. de Vries kindly informed me in a letter that this estimate is not to be regarded
as anything more than a rough guess.
[37] Stopes (10).
[38] Caldwell (07).
[39] Bower (84).
[40] Rosen (11).
[41] Seward (95) A. pp. 15 et seq.
[42] Braun, A. (75).
[43] Thiselton-Dyer (65) B.; Bot. Mag. 1909, Tab. 8242.
[44] Thiselton-Dyer (02) p. 560.
[45] Gard. Chron. 1904, June 11, p. 370.
[46] Seward (97).
[47] Braun, A. (752) p. 376.
[48] Bot. Mag. 1818, Tab. 1969.
[49] Matte (04) p. 34.
[50] Seward (95) A. p. 5; Robertson (02) fig. 4.
[51] Vol. ii. fig. 287, p. 389.
[52] Chamberlain (09).
[53] Braun, A. (75); Bornemann (56) A. Pl. x.
[54] Caldwell (07); Caldwell and Baker (07).
[55] Bot. Mag. 1859, Tab. 5121.
[56] Vol. ii. p. 485.
[57] Lignier (94).
[58] Chamberlain (123).
[59] For information on the anatomy of reproductive shoots, see Thibout (96); Scott
(97); Worsdell (98); Matte (04).
[60] Thiselton-Dyer (01); Bot. Mag. 1915, Tab. 8592, 8593. For instances of monstrous
cones, see Miquel (69), Wieland (02).
[61] Chamberlain (09).
[62] Dorrien-Smith (11) p. 287.
[63] Stopes (04) p. 467.
Page 745
[64] Stopes (04) p. 438, fig. 1; Warming (77) Pl. iii.
[65] Chamberlain (06).
[66] Kershaw (12).
[67] Stopes (04).
[68] Oliver (13).
[69] Thoday (Sykes) (11); Sykes (10); Thoday (Sykes) and Berridge (12).
[70] Salisbury (14) p. 72.
[71] Kraus (96).
[72] Pearson (06).
[73] Rattray (13).
[74] Worsdell (96); (01).
[75] See ante, p. 5.
[76] Chamberlain (11); Wieland (06).
[77] Pavolini (09); Marsh (14).
[78] Matte (08).
[79] Dorety (082); (09).
[80] Worsdell (96).
[81] Matte (04) especially pp. 185–202. See also Worsdell (00); (06) etc.
[82] Matte (04) p. 210.
[83] Worsdell (982).
[84] Caldwell (07).
[85] Carano (04); le Goc (14); Marsh (14).
[86] Le Goc (14); Marsh (14).
[87] Seward (06).
[88] Robertson (02).
[89] Seward (122).
[90] Worsdell (98).
[91] Lignier (92).
[92] Nestler (95); Porsch (05); Thomas and Bancroft (13); Dušánek (13).
[93] Binney (66).
[94] Unger (50) A. p. 378.
[95] Williamson (69).
[96] Williamson (73) A.
[97] Gourlie (44).
[98] See page 186.
[99] Solms-Laubach (91) A. pp. 8, 217, 218.
[100] Solms-Laubach (91) A. pp. 8, 217, 218.
[65] Chamberlain (06).
[66] Kershaw (12).
[67] Stopes (04).
[68] Oliver (13).
[69] Thoday (Sykes) (11); Sykes (10); Thoday (Sykes) and Berridge (12).
[70] Salisbury (14) p. 72.
[71] Kraus (96).
[72] Pearson (06).
[73] Rattray (13).
[74] Worsdell (96); (01).
[75] See ante, p. 5.
[76] Chamberlain (11); Wieland (06).
[77] Pavolini (09); Marsh (14).
[78] Matte (08).
[79] Dorety (082); (09).
[80] Worsdell (96).
[81] Matte (04) especially pp. 185–202. See also Worsdell (00); (06) etc.
[82] Matte (04) p. 210.
[83] Worsdell (982).
[84] Caldwell (07).
[85] Carano (04); le Goc (14); Marsh (14).
[86] Le Goc (14); Marsh (14).
[87] Seward (06).
[88] Robertson (02).
[89] Seward (122).
[90] Worsdell (98).
[91] Lignier (92).
[92] Nestler (95); Porsch (05); Thomas and Bancroft (13); Dušánek (13).
[93] Binney (66).
[94] Unger (50) A. p. 378.
[95] Williamson (69).
[96] Williamson (73) A.
[97] Gourlie (44).
[98] See page 186.
[99] Solms-Laubach (91) A. pp. 8, 217, 218.
[100] Solms-Laubach (91) A. pp. 8, 217, 218.
Page 746
[101] Vol. ii. p. 220.
[102] Nathorst (14) Pl. vii. fig. 1.
[103] Nathorst (04) B. p. 11.
[104] Potonié (99) B. p. 171.
[105] Arber, E. A. N. (02).
[106] Williamson and Scott (95).
[107] Williamson and Scott (95) p. 720.
[108] Williamson (90) Pl. xii. fig. 6.
[109] Williamson (90) Pl. xiii. fig. 3, b.
[110] Williamson and Scott (95) Pl. xxiii. fig. 8.
[111] Ibid. p. 722.
[112] Worsdell (06) pp. 140 et seq.
[113] Lomax (02).
[114] Brenchley (13).
[115] For a description of the method, see Salisbury (13).
[116] Williamson (73) A. p. 403.
[117] Williamson (90).
[118] Vol. ii. p. 299, fig. 232.
[119] Bower (12) Pls. xxx. xxxiii.
[120] Höhlke (02).
[121] Williamson (74) Pl. li. fig. 1.
[122] Scott (09) B. fig. 139, p. 375.
[123] Brongniart (28) A. p. 199, Pl. lii. For synonymy, see Kidston (11) p. 42.
[124] Zeiller (88) A. p. 82, Pl. vi.
[125] See also Kidston (06) B, fig. 5, p. 417; Renier (102), Pls. 60, 70.
[126] Kidston (06) B.
[127] Stur (77) p. 257, Pls. xxv. xxvi.
[128] Oliver (05) fig. 6.
[129] Gothan (13) p. 40.
[130] Johnson (11).
[131] Kidston (05).
[132] Kidston (06) B.
[133] Zeiller (83) B.
[134] Gothan (13) p. 49.
[135] Chodat (08) B.
[136] Scott (08) B. p. 292.
[137] Weiss, F. E. (12).
[102] Nathorst (14) Pl. vii. fig. 1.
[103] Nathorst (04) B. p. 11.
[104] Potonié (99) B. p. 171.
[105] Arber, E. A. N. (02).
[106] Williamson and Scott (95).
[107] Williamson and Scott (95) p. 720.
[108] Williamson (90) Pl. xii. fig. 6.
[109] Williamson (90) Pl. xiii. fig. 3, b.
[110] Williamson and Scott (95) Pl. xxiii. fig. 8.
[111] Ibid. p. 722.
[112] Worsdell (06) pp. 140 et seq.
[113] Lomax (02).
[114] Brenchley (13).
[115] For a description of the method, see Salisbury (13).
[116] Williamson (73) A. p. 403.
[117] Williamson (90).
[118] Vol. ii. p. 299, fig. 232.
[119] Bower (12) Pls. xxx. xxxiii.
[120] Höhlke (02).
[121] Williamson (74) Pl. li. fig. 1.
[122] Scott (09) B. fig. 139, p. 375.
[123] Brongniart (28) A. p. 199, Pl. lii. For synonymy, see Kidston (11) p. 42.
[124] Zeiller (88) A. p. 82, Pl. vi.
[125] See also Kidston (06) B, fig. 5, p. 417; Renier (102), Pls. 60, 70.
[126] Kidston (06) B.
[127] Stur (77) p. 257, Pls. xxv. xxvi.
[128] Oliver (05) fig. 6.
[129] Gothan (13) p. 40.
[130] Johnson (11).
[131] Kidston (05).
[132] Kidston (06) B.
[133] Zeiller (83) B.
[134] Gothan (13) p. 49.
[135] Chodat (08) B.
[136] Scott (08) B. p. 292.
[137] Weiss, F. E. (12).
Page 747
[138] Vol. ii. p. 532.
[139] Scott (09) B. p. 400.
[140] Kidston (06) B.
[141] Benson (04) B.
[142] In his account of the ovule of Stangeria Lang (00) discusses the possibility of
homologising the ovule with a sorus consisting of one sporangium.
[143] Williamson (77) B. p. 234.
[144] Oliver and Scott (03): (04).
[145] Hörich (06) p. 48.
[146] Kidston (052) B.
[147] Grand’Eury (052) B.
[148] Oliver and Scott (04) Pl. x. fig. 28; McLean (12).
[149] Williamson (76).
[150] Oliver (03) p. 462.
[151] Benson (08).
[152] McLean (12).
[153] For figure, see Lotsy (09) p. 714.
[154] Scott (11) p. 105.
[155] Chodat (08) B.
[156] Scott (03).
[157] Scott (09) B. p. 220. See also Oliver (05); Oliver and Scott (04) p. 231.
[158] Gibbs (12) p. 46.
[159] Oliver (06).
[160] Stopes(05); Prankerd (12).
[161] Sykes (10) p. 219; Thoday (Sykes, M. G.) (11) p. 1124.
[162] Shaw (08).
[163] Benson and Welsford (09) p. 633.
[164] Kershaw (09) p. 359.
[165] Benson (08).
[166] Zopf (92) Pls. i. ii.
[167] Burlingame (15).
[168] Williamson (77) B.
[169] Williamson (76) p. 160.
[170] Butterworth (97).
[171] Oliver (09) p. 74.
[172] Prankerd (12).
[173] Vol. ii. p. 364, fig. 270.
[139] Scott (09) B. p. 400.
[140] Kidston (06) B.
[141] Benson (04) B.
[142] In his account of the ovule of Stangeria Lang (00) discusses the possibility of
homologising the ovule with a sorus consisting of one sporangium.
[143] Williamson (77) B. p. 234.
[144] Oliver and Scott (03): (04).
[145] Hörich (06) p. 48.
[146] Kidston (052) B.
[147] Grand’Eury (052) B.
[148] Oliver and Scott (04) Pl. x. fig. 28; McLean (12).
[149] Williamson (76).
[150] Oliver (03) p. 462.
[151] Benson (08).
[152] McLean (12).
[153] For figure, see Lotsy (09) p. 714.
[154] Scott (11) p. 105.
[155] Chodat (08) B.
[156] Scott (03).
[157] Scott (09) B. p. 220. See also Oliver (05); Oliver and Scott (04) p. 231.
[158] Gibbs (12) p. 46.
[159] Oliver (06).
[160] Stopes(05); Prankerd (12).
[161] Sykes (10) p. 219; Thoday (Sykes, M. G.) (11) p. 1124.
[162] Shaw (08).
[163] Benson and Welsford (09) p. 633.
[164] Kershaw (09) p. 359.
[165] Benson (08).
[166] Zopf (92) Pls. i. ii.
[167] Burlingame (15).
[168] Williamson (77) B.
[169] Williamson (76) p. 160.
[170] Butterworth (97).
[171] Oliver (09) p. 74.
[172] Prankerd (12).
[173] Vol. ii. p. 364, fig. 270.
Page 748
[174] Berridge (11).
[175] Lignier (132).
[176] Nathorst (14) p. 29.
[177] Arber (05).
[178] Oliver (09).
[179] Arber (14) p. 102.
[180] Vol. ii. pp. 294, 295.
[181] Vol. ii. p. 529, fig. 352.
[182] Carpentier (11) p. 3.
[183] See page 66.
[184] Kidston (14) p. 160, Pl. vii. figs. 1, 2.
[185] Ibid. p. 161, Pl. xvi. figs. 9, 10.
[186] Grand’Eury (052) B.
[187] Carpentier (11).
[188] Arber, E. A. N. (08).
[189] Nathorst (08) p. 10, Pl. ii. figs. 19–21.
[190] Stopes (14) p. 74, Pls. xvii. fig. 45, xxv. fig. 69, text-fig. 15.
[191] See page 124.
[192] Nathorst (14) p. 23, Pl. xv. fig. 43.
[193] Carpentier (13) p. 391.
[194] Williamson (76) B.
[195] Williamson (87) p. 297.
[196] Felix (86) A. p. 51.
[197] Williamson and Scott (94).
[198] Hick (95) p. 114.
[199] Stopes and Watson (08) Pl. xvii. fig. 1.
[200] Weiss, F. E. (13).
[201] Williamson and Scott (95) p. 739.
[202] White (99) B. p. 40.
[203] Felix (86) A.
[204] Zalessky (10).
[205] Kubart (14); (11).
[206] Corda (45) A. Pl. xvi.
[207] Kubart (08) fig. 3.
[208] Vol. ii. p. 310, fig. 237, C; p. 311, fig. 238.
[209] Williamson (73) A. p. 403.
[210] Benson (14).
[175] Lignier (132).
[176] Nathorst (14) p. 29.
[177] Arber (05).
[178] Oliver (09).
[179] Arber (14) p. 102.
[180] Vol. ii. pp. 294, 295.
[181] Vol. ii. p. 529, fig. 352.
[182] Carpentier (11) p. 3.
[183] See page 66.
[184] Kidston (14) p. 160, Pl. vii. figs. 1, 2.
[185] Ibid. p. 161, Pl. xvi. figs. 9, 10.
[186] Grand’Eury (052) B.
[187] Carpentier (11).
[188] Arber, E. A. N. (08).
[189] Nathorst (08) p. 10, Pl. ii. figs. 19–21.
[190] Stopes (14) p. 74, Pls. xvii. fig. 45, xxv. fig. 69, text-fig. 15.
[191] See page 124.
[192] Nathorst (14) p. 23, Pl. xv. fig. 43.
[193] Carpentier (13) p. 391.
[194] Williamson (76) B.
[195] Williamson (87) p. 297.
[196] Felix (86) A. p. 51.
[197] Williamson and Scott (94).
[198] Hick (95) p. 114.
[199] Stopes and Watson (08) Pl. xvii. fig. 1.
[200] Weiss, F. E. (13).
[201] Williamson and Scott (95) p. 739.
[202] White (99) B. p. 40.
[203] Felix (86) A.
[204] Zalessky (10).
[205] Kubart (14); (11).
[206] Corda (45) A. Pl. xvi.
[207] Kubart (08) fig. 3.
[208] Vol. ii. p. 310, fig. 237, C; p. 311, fig. 238.
[209] Williamson (73) A. p. 403.
[210] Benson (14).
Page 749
[211] Williamson (722).
[212] Williamson (73) A.
[213] Williamson (90).
[214] Williamson and Scott (95).
[215] Scott (15).
[216] Scott (15).
[217] Jeffrey (05) Pl. iii. fig. 21.
[218] Kidston (912) B. p. 49.
[219] Williamson and Scott (95) p. 753.
[220] Williamson and Scott (95) Pl. xxvii. fig. 28.
[221] Stur (77) p. 236, Pls. xiii. xiv.
[222] Benson (14).
[223] Oliver (09) p. 111.
[224] Grand’Eury (052).
[225] Carpentier (11) Pl. xii. fig. 1.
[226] For a fuller description, see Williamson and Scott (95).
[227] Scott (09) B. p. 410; (15).
[228] Scott (15).
[229] Renault (79) B. p. 276, Pl. xiv. figs. 4–8; (96) A. p. 251, Pl. lxv. figs. 1, 2.
[230] Renault (96) A. pp. 253, 255.
[231] Ibid. p. 252, Pl. lxv. figs. 3, 6.
[232] Kubart (14).
[233] Dr. Scott who has seen sections of this species tells me that it is a striking
intermediate form.
[234] Johnson (12).
[235] Scott (15).
[236] Goeppert and Stenzel (81).
[237] Lotsy (09) p. 723.
[238] Zeiller (05) B. p. 725.
[239] Schenck (93) B. Pls. i–v, etc.
[240] White, D. (052) B. p. 389.
[241] Solms-Laubach (97) Pl. vi. fig. 3.
[242] Penhallow (97).
[243] Cotta (32) B. p. 59.
[244] Brongniart (49) A. p. 57.
[245] Scott (99).
[246] Arber, E. A. N. (03).
[212] Williamson (73) A.
[213] Williamson (90).
[214] Williamson and Scott (95).
[215] Scott (15).
[216] Scott (15).
[217] Jeffrey (05) Pl. iii. fig. 21.
[218] Kidston (912) B. p. 49.
[219] Williamson and Scott (95) p. 753.
[220] Williamson and Scott (95) Pl. xxvii. fig. 28.
[221] Stur (77) p. 236, Pls. xiii. xiv.
[222] Benson (14).
[223] Oliver (09) p. 111.
[224] Grand’Eury (052).
[225] Carpentier (11) Pl. xii. fig. 1.
[226] For a fuller description, see Williamson and Scott (95).
[227] Scott (09) B. p. 410; (15).
[228] Scott (15).
[229] Renault (79) B. p. 276, Pl. xiv. figs. 4–8; (96) A. p. 251, Pl. lxv. figs. 1, 2.
[230] Renault (96) A. pp. 253, 255.
[231] Ibid. p. 252, Pl. lxv. figs. 3, 6.
[232] Kubart (14).
[233] Dr. Scott who has seen sections of this species tells me that it is a striking
intermediate form.
[234] Johnson (12).
[235] Scott (15).
[236] Goeppert and Stenzel (81).
[237] Lotsy (09) p. 723.
[238] Zeiller (05) B. p. 725.
[239] Schenck (93) B. Pls. i–v, etc.
[240] White, D. (052) B. p. 389.
[241] Solms-Laubach (97) Pl. vi. fig. 3.
[242] Penhallow (97).
[243] Cotta (32) B. p. 59.
[244] Brongniart (49) A. p. 57.
[245] Scott (99).
[246] Arber, E. A. N. (03).
Page 750
[247] Renault (76) B.
[248] Arber, E. A. N. (03).
[249] Kidston (052) B.
[250] Scott (09) B. p. 441 (footnote).
[251] Scott (14).
[252] De Fraine (14).
[253] De Fraine (14) p. 259. See also Kisch (13).
[254] Cotta (32) B. p. 66, Pl. xiii. The well-preserved specimen figured by Cotta in his
Pl. xiii. fig. 2 is in the Dresden Museum.
[255] Goeppert (65) A. p. 209, Pls. xl.–xliii.
[256] Goeppert and Stenzel (81).
[257] Weber and Sterzel (96) B.
[258] Schenk (89).
[259] Weber and Sterzel (96) B. p. 51; Schenk (89).
[260] No. V. 8093.
[261] Schenk (82). See also Zeiller (90) B. p. 286.
[262] No. 13767, probably identical with M. stellata var. lignosa Weber and Sterzel.
[263] Mougeot (52) A. p. 36, Pl. iii. figs. 8–10.
[264] Weber and Sterzel (96) B. p. 108.
[265] Ibid. p. 56.
[266] Weber and Sterzel (96) B. p. 63.
[267] Ibid. p. 66.
[268] Renault (96) A. p. 297; (93) A. Pl. lxxi. figs. 1–6.
[269] Brongniart (49) A. p. 77.
[270] Cotta (32) B. p. 63, Pl. xii. figs. 6, 7.
[271] Schenk (89) p. 339.
[272] Weber and Sterzel (96) B. p. 541, Pls. ii. iii.
[273] Goeppert and Stenzel (81) p. 123, Pl. xvi. figs. 13–15; Solms-Laubach (97); Weber
and Sterzel (96) B. p. 79, Pls. iv. v. ix.
[274] Goeppert and Stenzel (81) Pl. iii. fig. 15.
[275] Solms-Laubach (97) p. 179.
[276] Scott (99) p. 90.
[277] Weber and Sterzel (96) B. p. 95, Pl. ix.
[278] Solms-Laubach (97).
[279] Renault (76) B. p. 7.
[280] Grand’Eury (77) A. p. 122; (90) A. p. 287.
[281] Seward (93).
[282] Penhallow (97).
[248] Arber, E. A. N. (03).
[249] Kidston (052) B.
[250] Scott (09) B. p. 441 (footnote).
[251] Scott (14).
[252] De Fraine (14).
[253] De Fraine (14) p. 259. See also Kisch (13).
[254] Cotta (32) B. p. 66, Pl. xiii. The well-preserved specimen figured by Cotta in his
Pl. xiii. fig. 2 is in the Dresden Museum.
[255] Goeppert (65) A. p. 209, Pls. xl.–xliii.
[256] Goeppert and Stenzel (81).
[257] Weber and Sterzel (96) B.
[258] Schenk (89).
[259] Weber and Sterzel (96) B. p. 51; Schenk (89).
[260] No. V. 8093.
[261] Schenk (82). See also Zeiller (90) B. p. 286.
[262] No. 13767, probably identical with M. stellata var. lignosa Weber and Sterzel.
[263] Mougeot (52) A. p. 36, Pl. iii. figs. 8–10.
[264] Weber and Sterzel (96) B. p. 108.
[265] Ibid. p. 56.
[266] Weber and Sterzel (96) B. p. 63.
[267] Ibid. p. 66.
[268] Renault (96) A. p. 297; (93) A. Pl. lxxi. figs. 1–6.
[269] Brongniart (49) A. p. 77.
[270] Cotta (32) B. p. 63, Pl. xii. figs. 6, 7.
[271] Schenk (89) p. 339.
[272] Weber and Sterzel (96) B. p. 541, Pls. ii. iii.
[273] Goeppert and Stenzel (81) p. 123, Pl. xvi. figs. 13–15; Solms-Laubach (97); Weber
and Sterzel (96) B. p. 79, Pls. iv. v. ix.
[274] Goeppert and Stenzel (81) Pl. iii. fig. 15.
[275] Solms-Laubach (97) p. 179.
[276] Scott (99) p. 90.
[277] Weber and Sterzel (96) B. p. 95, Pl. ix.
[278] Solms-Laubach (97).
[279] Renault (76) B. p. 7.
[280] Grand’Eury (77) A. p. 122; (90) A. p. 287.
[281] Seward (93).
[282] Penhallow (97).
Page 751
[283] Williamson (76) B. p. 8.
[284] Zeiller (90) B.
[285] Weber and Sterzel (96) B. p. 102, fig. 26.
[286] Seward (93).
[287] Renault (76) B.
[288] Penhallow (97).
[289] Weber and Sterzel (96) B. p. 139.
[290] Page 142.
[291] Holden, H. S. (10).
[292] Vol. ii. p. 568, fig. 371.
[293] Kidston (87) B.
[294] Bertrand, P. (13) p. 117.
[295] Carpentier (11) p. 10.
[296] Lesquereux (80) A. p. 328, Pl. xlviii.
[297] Bertrand, P. (13) p. 120.
[298] Zeiller (99) B. p. 52, Pl. iv. fig. 19.
[299] Carpentier (11) p. 12, Pls xvi. xvii.
[300] Carpentier (13) p. 387, Pl. x. figs. 1–6.
[301] Bertrand, P. (13) p. 125.
[302] Kidston (14) p. 108.
[303] Ibid. p. 112, Pl. viii. figs. 1–7.
[304] Carpentier (11) p. 13, Pl. xvi. fig. 1.
[305] See page 127.
[306] Renault and Zeiller (88) A. p. 273, Pl. xxxi. figs. 2, 4.
[307] Zeiller (90) B. Pl. xi. fig. 9; (00)2 B. p. 108, fig. 83. See Vol. ii. p. 572.
[308] Bertrand, P. (13) p. 132, Pl. vi. fig. 7.
[309] Carpentier (13) p. 375, Pl. viii. fig. 1.
[310] Bertrand, P. (13) p. 135, pl. vi. figs. 2–4.
[311] Kidston (04); (042); (14) p. 107, fig. 5.
[312] Renault and Zeiller (88) A. Pl. lxxii. fig. 19.
[313] Grand’Eury (90) A. Pl. vi. fig. 6.
[314] Kidston and Jongmans (11).
[315] Grand’Eury (04); (042).
[316] Cf. also Rhabdocarpus conicus and other forms figured by Renault (93) A. Pl.
lxxxvi.
[317] Brongniart (74) Pl. xxi.; (81) Pls. ix.–xi.
[318] See Chapter xxxv.
[284] Zeiller (90) B.
[285] Weber and Sterzel (96) B. p. 102, fig. 26.
[286] Seward (93).
[287] Renault (76) B.
[288] Penhallow (97).
[289] Weber and Sterzel (96) B. p. 139.
[290] Page 142.
[291] Holden, H. S. (10).
[292] Vol. ii. p. 568, fig. 371.
[293] Kidston (87) B.
[294] Bertrand, P. (13) p. 117.
[295] Carpentier (11) p. 10.
[296] Lesquereux (80) A. p. 328, Pl. xlviii.
[297] Bertrand, P. (13) p. 120.
[298] Zeiller (99) B. p. 52, Pl. iv. fig. 19.
[299] Carpentier (11) p. 12, Pls xvi. xvii.
[300] Carpentier (13) p. 387, Pl. x. figs. 1–6.
[301] Bertrand, P. (13) p. 125.
[302] Kidston (14) p. 108.
[303] Ibid. p. 112, Pl. viii. figs. 1–7.
[304] Carpentier (11) p. 13, Pl. xvi. fig. 1.
[305] See page 127.
[306] Renault and Zeiller (88) A. p. 273, Pl. xxxi. figs. 2, 4.
[307] Zeiller (90) B. Pl. xi. fig. 9; (00)2 B. p. 108, fig. 83. See Vol. ii. p. 572.
[308] Bertrand, P. (13) p. 132, Pl. vi. fig. 7.
[309] Carpentier (13) p. 375, Pl. viii. fig. 1.
[310] Bertrand, P. (13) p. 135, pl. vi. figs. 2–4.
[311] Kidston (04); (042); (14) p. 107, fig. 5.
[312] Renault and Zeiller (88) A. Pl. lxxii. fig. 19.
[313] Grand’Eury (90) A. Pl. vi. fig. 6.
[314] Kidston and Jongmans (11).
[315] Grand’Eury (04); (042).
[316] Cf. also Rhabdocarpus conicus and other forms figured by Renault (93) A. Pl.
lxxxvi.
[317] Brongniart (74) Pl. xxi.; (81) Pls. ix.–xi.
[318] See Chapter xxxv.
Page 752
[319] See Chapter xxxv.
[320] P. Bertrand (13) p. 129, Pl. vii. figs. 1, 2, 7.
[321] See Chapter xxxv.
[322] See page 139.
[323] Arber (14) pp. 93, 103, Pl. viii. fig. 47.
[324] P. Bertrand (13) p. 121.
[325] Grand’Eury (042) p. 785 (footnote).
[326] Chodat (08) B. p. 33, fig. 15.
[327] Lotsy (09) p. 72.
[328] Grand’Eury (04); (04) B.
[329] Brongniart (28) A. p. 137.
[330] Williamson (77) B.; Scott and Maslen (07) p. 90 (footnote) also refer to
Trigonocarpon as having been used by Brongniart in 1849.
[331] Brongniart (49) A. p. 91.
[332] Lindley and Hutton (35) A. p. 172.
[333] Hooker and Binney (55).
[334] Lindley and Hutton (33) A. Pl. 87.
[335] Wild (00).
[336] Scott and Maslen (07) p. 96.
[337] Scott and Maslen (07).
[338] Arber, A (14).
[339] Oliver (04) p. 97.
[340] Salisbury (14) p. 65.
[341] Arber, E. A. N. (14) p. 95, Pl. vi. fig. 1.
[342] Lindley and Hutton (37) A. Pl. 221; Arber loc. cit. p. 95, Pl. vi. fig. 8.
[343] Fiedler (57) Pl. xxvii. fig. 39.
[344] Lesquereux (80) A. Pl. 85; (84) A. Pl. iii.
[345] Salisbury (14).
[346] See page 115.
[347] Renault (96) A. p. 399; (93) A. Pl. lxxxv. fig. 9; Salisbury (14) p. 66.
[348] Sellards (03) p. 90; (07).
[349] Lesquereux (80) A. p. 93; (84) A. p. 733, Pl. xciv. figs. 1, 2.
[350] Stopes (14) p. 74. See page 66.
[351] Nathorst (14) p. 23. See page 67.
[352] Geinitz (63) p. 525, Pl. vi.
[353] Goeppert (65) p. 161, Pls. xxiii–iv. The specimens figured by Goeppert, which I
saw some years ago in the Breslau Museum, do not show the finer characters very
clearly.
[320] P. Bertrand (13) p. 129, Pl. vii. figs. 1, 2, 7.
[321] See Chapter xxxv.
[322] See page 139.
[323] Arber (14) pp. 93, 103, Pl. viii. fig. 47.
[324] P. Bertrand (13) p. 121.
[325] Grand’Eury (042) p. 785 (footnote).
[326] Chodat (08) B. p. 33, fig. 15.
[327] Lotsy (09) p. 72.
[328] Grand’Eury (04); (04) B.
[329] Brongniart (28) A. p. 137.
[330] Williamson (77) B.; Scott and Maslen (07) p. 90 (footnote) also refer to
Trigonocarpon as having been used by Brongniart in 1849.
[331] Brongniart (49) A. p. 91.
[332] Lindley and Hutton (35) A. p. 172.
[333] Hooker and Binney (55).
[334] Lindley and Hutton (33) A. Pl. 87.
[335] Wild (00).
[336] Scott and Maslen (07) p. 96.
[337] Scott and Maslen (07).
[338] Arber, A (14).
[339] Oliver (04) p. 97.
[340] Salisbury (14) p. 65.
[341] Arber, E. A. N. (14) p. 95, Pl. vi. fig. 1.
[342] Lindley and Hutton (37) A. Pl. 221; Arber loc. cit. p. 95, Pl. vi. fig. 8.
[343] Fiedler (57) Pl. xxvii. fig. 39.
[344] Lesquereux (80) A. Pl. 85; (84) A. Pl. iii.
[345] Salisbury (14).
[346] See page 115.
[347] Renault (96) A. p. 399; (93) A. Pl. lxxxv. fig. 9; Salisbury (14) p. 66.
[348] Sellards (03) p. 90; (07).
[349] Lesquereux (80) A. p. 93; (84) A. p. 733, Pl. xciv. figs. 1, 2.
[350] Stopes (14) p. 74. See page 66.
[351] Nathorst (14) p. 23. See page 67.
[352] Geinitz (63) p. 525, Pl. vi.
[353] Goeppert (65) p. 161, Pls. xxiii–iv. The specimens figured by Goeppert, which I
saw some years ago in the Breslau Museum, do not show the finer characters very
clearly.
Page 753
[354] Goeppert (65) p. 164, Pls. xxiv–v.
[355] Schimper (72) A. p. 358.
[356] Kidston (84) Pl. v. fig. 2.
[357] Renault (96) A. p. 379, fig. 73.
[358] Zeiller in Douvillé and Zeiller (08).
[359] See page 124.
[360] Newberry (54).
[361] Lesquereux (80) A. p. 523, Pl. iv; (84). For other references see Potonié (04).
[362] White, D. (01).
[363] Thomas, H. H. (12); Kidston (14) p. 166.
[364] Renault (93) A. Pl. lxxii; (96) A. p. 268. See page 137.
[365] Page 111.
[366] White (01) p. 108.
[367] Ibid. p. 104, Pl. vii. figs. 3, 3a.
[368] Matthew (10).
[369] Stopes (14) p. 78.
[370] Kidston (14) p. 166, Pl. xv. figs. 1–10.
[371] Saporta (78).
[372] Eichwald (55) Pl. xviii. fig. 18; (60) p. 252.
[373] Goeppert (65) p. 157, Pl. xxi. fig. 4.
[374] Saporta (782).
[375] Saporta and Marion (85) pp. 16, 68.
[376] Grand’Eury (77) A. p. 192.
[377] Zeiller (002) B. p. 217.
[378] Kutorga (42).
[379] Unger (50) A. p. 334.
[380] Renault (96) A. p. 262.
[381] No. V. 8114.
[382] A specimen from Orenburg in the Dresden Museum shows the same surface-
features as the British Museum specimen and agrees with the originals of Goeppert’s
figures which are in the Breslau University Museum.
[383] Renault (96) A. p. 265, fig. 43.
[384] Renault (96) A. p. 262, Pl. xxii. fig. 1.
[385] Grand’Eury (77) A. p. 196, Pl. xvi; (90) A. Pl. viii. fig. 1; Zeiller (06) B. p. 192.
[386] Renault and Zeiller (90) A. p. 556, Pl. lvii.
[387] Grand’Eury (04).
[388] Roehl (69) B. Pl. xvii.
[355] Schimper (72) A. p. 358.
[356] Kidston (84) Pl. v. fig. 2.
[357] Renault (96) A. p. 379, fig. 73.
[358] Zeiller in Douvillé and Zeiller (08).
[359] See page 124.
[360] Newberry (54).
[361] Lesquereux (80) A. p. 523, Pl. iv; (84). For other references see Potonié (04).
[362] White, D. (01).
[363] Thomas, H. H. (12); Kidston (14) p. 166.
[364] Renault (93) A. Pl. lxxii; (96) A. p. 268. See page 137.
[365] Page 111.
[366] White (01) p. 108.
[367] Ibid. p. 104, Pl. vii. figs. 3, 3a.
[368] Matthew (10).
[369] Stopes (14) p. 78.
[370] Kidston (14) p. 166, Pl. xv. figs. 1–10.
[371] Saporta (78).
[372] Eichwald (55) Pl. xviii. fig. 18; (60) p. 252.
[373] Goeppert (65) p. 157, Pl. xxi. fig. 4.
[374] Saporta (782).
[375] Saporta and Marion (85) pp. 16, 68.
[376] Grand’Eury (77) A. p. 192.
[377] Zeiller (002) B. p. 217.
[378] Kutorga (42).
[379] Unger (50) A. p. 334.
[380] Renault (96) A. p. 262.
[381] No. V. 8114.
[382] A specimen from Orenburg in the Dresden Museum shows the same surface-
features as the British Museum specimen and agrees with the originals of Goeppert’s
figures which are in the Breslau University Museum.
[383] Renault (96) A. p. 265, fig. 43.
[384] Renault (96) A. p. 262, Pl. xxii. fig. 1.
[385] Grand’Eury (77) A. p. 196, Pl. xvi; (90) A. Pl. viii. fig. 1; Zeiller (06) B. p. 192.
[386] Renault and Zeiller (90) A. p. 556, Pl. lvii.
[387] Grand’Eury (04).
[388] Roehl (69) B. Pl. xvii.
Page 754
[389] Saporta and Marion (85) fig. 29.
[390] Renault (96) A, p. 267, Pl. lxxii.
[391] Solms-Laubach (91) A. p. 126.
[392] See Chapter xxxv.
[393] Zeiller (06) B. p. 227.
[394] Saporta and Marion (85) fig. 37, p. 76.
[395] Schmalhausen (87) Pl. v. figs. 7–9: this specimen, figured as Dolerophyllum
Goepperti, is very similar to Cordaites circularis [Grand’Eury (90) A. Pl. vi. fig. 15].
[396] Zeiller (02) B. p. 34, Pl. iv. figs. 9, 10.
[397] Bertrand, P. (13) p. 131, Pl. vii. fig. 6.
[398] Zeiller, loc. cit. p. 37.
[399] Feistmantel (79) B. p. 30; (81) A. p. 59, Pl. xxx. fig. 14; (82) B. p. 43, Pl. xv. figs.
5–12. Dr Arber [(05) B. p. 205] has substituted for Carpolithes the more appropriate
designation Cardiocarpus.
[400] Renault (96) A. p. 329; (93) A. Pl. lxxiii.
[401] Schimper and Mougeot (44) A. p. 31. Seward (08) B. p. 101.
[402] Brongniart (49) A. p. 60.
[403] Renault (96) A. p. 299; (93) A. Pls. 66, 67.
[404] Grand’Eury (08) B. p. 1242.
[405] Goeppert and Stenzel (81) p. 125; Weber and Sterzel (96) B. p. 79. Solms-Laubach
[(97) p. 196] draws attention to the resemblances between the leaf-scars of Colpoxylon
and Medullosa.q
[406] Klein (81) Pls. xxii.–xxiv.
[407] Bancroft (13).
[408] Page 205.
[409] Scott (06).
[410] de Fraine (12).
[411] Scott (06) p. 53.
[412] de Fraine (12).
[413] Reference should be made to the helpful drawings of models of the vascular
system in Miss de Fraine’s paper.
[414] For additional figures of the principal types of Medullosa, see Miss Bancroft’s
paper (14).
[415] Lotsy (09) p. 719.
[416] Scott (14) p. 998.
[417] Scott (99) p. 89.
[418] Worsdell (96); (98); (00); (06) etc.
[419] Matte (04); (08). See also Bancroft (14); Dorety (09).
[420] Scott (97).
[390] Renault (96) A, p. 267, Pl. lxxii.
[391] Solms-Laubach (91) A. p. 126.
[392] See Chapter xxxv.
[393] Zeiller (06) B. p. 227.
[394] Saporta and Marion (85) fig. 37, p. 76.
[395] Schmalhausen (87) Pl. v. figs. 7–9: this specimen, figured as Dolerophyllum
Goepperti, is very similar to Cordaites circularis [Grand’Eury (90) A. Pl. vi. fig. 15].
[396] Zeiller (02) B. p. 34, Pl. iv. figs. 9, 10.
[397] Bertrand, P. (13) p. 131, Pl. vii. fig. 6.
[398] Zeiller, loc. cit. p. 37.
[399] Feistmantel (79) B. p. 30; (81) A. p. 59, Pl. xxx. fig. 14; (82) B. p. 43, Pl. xv. figs.
5–12. Dr Arber [(05) B. p. 205] has substituted for Carpolithes the more appropriate
designation Cardiocarpus.
[400] Renault (96) A. p. 329; (93) A. Pl. lxxiii.
[401] Schimper and Mougeot (44) A. p. 31. Seward (08) B. p. 101.
[402] Brongniart (49) A. p. 60.
[403] Renault (96) A. p. 299; (93) A. Pls. 66, 67.
[404] Grand’Eury (08) B. p. 1242.
[405] Goeppert and Stenzel (81) p. 125; Weber and Sterzel (96) B. p. 79. Solms-Laubach
[(97) p. 196] draws attention to the resemblances between the leaf-scars of Colpoxylon
and Medullosa.q
[406] Klein (81) Pls. xxii.–xxiv.
[407] Bancroft (13).
[408] Page 205.
[409] Scott (06).
[410] de Fraine (12).
[411] Scott (06) p. 53.
[412] de Fraine (12).
[413] Reference should be made to the helpful drawings of models of the vascular
system in Miss de Fraine’s paper.
[414] For additional figures of the principal types of Medullosa, see Miss Bancroft’s
paper (14).
[415] Lotsy (09) p. 719.
[416] Scott (14) p. 998.
[417] Scott (99) p. 89.
[418] Worsdell (96); (98); (00); (06) etc.
[419] Matte (04); (08). See also Bancroft (14); Dorety (09).
[420] Scott (97).
Page 755
[421] Worsdell (06).
[422] Shaw (09).
[423] de Fraine (12) p. 1060.
[424] Sykes, M. G. (102); (10).
[425] Matte (04) Pls. xv. xvi.
[426] de Fraine (12).
[427] Scott (06) p. 64.
[428] Chodat (08) B. p. 38.
[429] Worsdell (06) pp. 140 et seq.
[430] Scott (09) B. p. 464.
[431] For a general summary of ‘Pteridosperm anatomy and its relation to that of the
Cycads’ see Bancroft (14).
[432] See p. 6.
[433] Dorety (092) p. 144.
[434] Goeppert and Stenzel (81) p. 126, Pl. xvii.
[435] Schenk (89) p. 525, Pl. i. figs. 1–16.
[436] Solms-Laubach (96) B. p. 62; (97) p. 197; (10) p. 542, Pl. iii. fig. 9.
[437] P. Bertrand (08); (11) p. 47 (footnote).
[438] In a recent note on Steloxylon to which Dr Scott has drawn my attention Bertrand
records the genus from Saalfeld (Upper Devonian) and expresses the opinion that
Steloxylon may be a condition of Cladoxylon and not a distinct type—P. Bertrand (14) p.
448.
[439] Vol. ii. p. 576.
[440] Schlotheim (04) A. Pl. x, fig. 19.
[441] For synonymy, see Kidston (86) A. p. 125 and Potonié (93) A. p. 81.
[442] Sterzel (83); (862) B.; Zeiller (06) B. p. 60.
[443] Stur (85) B. p. 293.
[444] Grand’Eury (05).
[445] See also Zeiller (05) B. p. 725.
[446] Grand’Eury (77) A. Pl. xxxiii. fig. 7.
[447] Vol. ii. p. 419, fig. 297.
[448] Zeiller (06) B. p. 63.
[449] For a more complete synonymy, see Kidston (03) B. p. 770.
[450] Brongniart (282) A. Pls. xlvi., xlvii.; Lebour (77) Pls. xxxiii.–iv.
[451] Kidston (14) p. 156; Duns (72).
[452] Howse (88) p. 45.
[453] Arber, E. A. N. (14) p. 97; (09) p. 29, Pl. i. fig. 5.
[454] Kidston (83) B. p. 540, Pl. xxxii. fig. 3.
[422] Shaw (09).
[423] de Fraine (12) p. 1060.
[424] Sykes, M. G. (102); (10).
[425] Matte (04) Pls. xv. xvi.
[426] de Fraine (12).
[427] Scott (06) p. 64.
[428] Chodat (08) B. p. 38.
[429] Worsdell (06) pp. 140 et seq.
[430] Scott (09) B. p. 464.
[431] For a general summary of ‘Pteridosperm anatomy and its relation to that of the
Cycads’ see Bancroft (14).
[432] See p. 6.
[433] Dorety (092) p. 144.
[434] Goeppert and Stenzel (81) p. 126, Pl. xvii.
[435] Schenk (89) p. 525, Pl. i. figs. 1–16.
[436] Solms-Laubach (96) B. p. 62; (97) p. 197; (10) p. 542, Pl. iii. fig. 9.
[437] P. Bertrand (08); (11) p. 47 (footnote).
[438] In a recent note on Steloxylon to which Dr Scott has drawn my attention Bertrand
records the genus from Saalfeld (Upper Devonian) and expresses the opinion that
Steloxylon may be a condition of Cladoxylon and not a distinct type—P. Bertrand (14) p.
448.
[439] Vol. ii. p. 576.
[440] Schlotheim (04) A. Pl. x, fig. 19.
[441] For synonymy, see Kidston (86) A. p. 125 and Potonié (93) A. p. 81.
[442] Sterzel (83); (862) B.; Zeiller (06) B. p. 60.
[443] Stur (85) B. p. 293.
[444] Grand’Eury (05).
[445] See also Zeiller (05) B. p. 725.
[446] Grand’Eury (77) A. Pl. xxxiii. fig. 7.
[447] Vol. ii. p. 419, fig. 297.
[448] Zeiller (06) B. p. 63.
[449] For a more complete synonymy, see Kidston (03) B. p. 770.
[450] Brongniart (282) A. Pls. xlvi., xlvii.; Lebour (77) Pls. xxxiii.–iv.
[451] Kidston (14) p. 156; Duns (72).
[452] Howse (88) p. 45.
[453] Arber, E. A. N. (14) p. 97; (09) p. 29, Pl. i. fig. 5.
[454] Kidston (83) B. p. 540, Pl. xxxii. fig. 3.
Page 756
[455] White refers some fronds from the Missouri Coal Measures to Eremopteris, but
their generic identity with the type-species is open to doubt. White (99) B. p. 16.
[456] White (04) B.
[457] Vol. ii. p. 376.
[458] Goeppert (362) A. p. 216.
[459] See page 64.
[460] Nathorst (14) p. 30, Pl. xv. figs. 18, 60–68.
[461] Schmalhausen (83) Pl. iv. figs. 13–15.
[462] Heer (77) A. Pl. v. pp. 23–25.
[463] Nathorst (14) p. 30, Pl. xv. fig. 59.
[464] Kidston (86) p. 70, Pl. iii. fig. 6.
[465] Arber, E. A. N. (14) p. 96, Pl. vi. fig. 12.
[466] Seward (99) B.
[467] For additional figures, see Seward (99) B.
[468] Vol. ii. p. 326.
[469] Scott (09) B. p. 476.
[470] Gordon (12). The rich development of secretory tissue suggested the name
Rhetinangium (ῥητίνη, resinous gum): the same prefix had previously been adopted by
Renault in his genus Retinodendron [Renault (96) A. p. 365].
[471] Scott (15).
[472] Page 90.
[473] Kubart (14).
[474] Kidston and Gwynne-Vaughan (12).
[475] Similar to the Dictyoxylon type except in the independent and not anastomosing
course of the stereome strands.
[476] Kidston and Gwynne-Vaughan (12) p. 269.
[477] Renault (96) A. p. 307.
[478] Renault (96) A. p. 308, figs. 55, 56.
[479] Seward (972).
[480] Scott (00) B. p. 364.
[481] A second band is sometimes present. Scott (00) B. p. 484.
[482] πτύξ, a fold.
[483] Renault (89); (96) A; (93) A. Pl. lxix.
[484] Scott (09) B. p. 492.
[485] Klein (81).
[486] Richter and Unger (56) B.
[487] Unger (54) p. 599.
[488] Solms-Laubach (96) B.
their generic identity with the type-species is open to doubt. White (99) B. p. 16.
[456] White (04) B.
[457] Vol. ii. p. 376.
[458] Goeppert (362) A. p. 216.
[459] See page 64.
[460] Nathorst (14) p. 30, Pl. xv. figs. 18, 60–68.
[461] Schmalhausen (83) Pl. iv. figs. 13–15.
[462] Heer (77) A. Pl. v. pp. 23–25.
[463] Nathorst (14) p. 30, Pl. xv. fig. 59.
[464] Kidston (86) p. 70, Pl. iii. fig. 6.
[465] Arber, E. A. N. (14) p. 96, Pl. vi. fig. 12.
[466] Seward (99) B.
[467] For additional figures, see Seward (99) B.
[468] Vol. ii. p. 326.
[469] Scott (09) B. p. 476.
[470] Gordon (12). The rich development of secretory tissue suggested the name
Rhetinangium (ῥητίνη, resinous gum): the same prefix had previously been adopted by
Renault in his genus Retinodendron [Renault (96) A. p. 365].
[471] Scott (15).
[472] Page 90.
[473] Kubart (14).
[474] Kidston and Gwynne-Vaughan (12).
[475] Similar to the Dictyoxylon type except in the independent and not anastomosing
course of the stereome strands.
[476] Kidston and Gwynne-Vaughan (12) p. 269.
[477] Renault (96) A. p. 307.
[478] Renault (96) A. p. 308, figs. 55, 56.
[479] Seward (972).
[480] Scott (00) B. p. 364.
[481] A second band is sometimes present. Scott (00) B. p. 484.
[482] πτύξ, a fold.
[483] Renault (89); (96) A; (93) A. Pl. lxix.
[484] Scott (09) B. p. 492.
[485] Klein (81).
[486] Richter and Unger (56) B.
[487] Unger (54) p. 599.
[488] Solms-Laubach (96) B.
Page 757
[489] Zalessky (11).
[490] Scott and Jeffrey (14).
[491] κάλυμμα, a veil or covering.
[492] White (052) B. p. 384.
[493] Richter and Unger (56) B. p. 174, Pl. x. figs. 1–3; Solms-Laubach (96) B. p. 73;
Scott (12) p. 1027.
[494] Scott and Jeffrey (14) p. 326.
[495] Ibid. p. 317, Pls. 27, 28, 30, 31.
[496] Scott (02).
[497] Scott and Jeffrey (14) p. 328, refer to a specimen over 6 cm. in diameter: these
authors give several excellent figures of Kalymma.
[498] Dawson and Penhallow (91).
[499] ἐριστός, to be disputed.
[500] Zalessky (11).
[501] Scott (992).
[502] Scott (02).
[503] Scott (02) p. 336.
[504] Page 175.
[505] Scott (12) p. 1027.
[506] Tuzson (09).
[507] Unger and Richter (56) B. p. 178.
[508] Scott and Jeffrey (14) p. 364.
[509] Solms-Laubach (96) B.
[510] P. Bertrand (08).
[511] Unger and Richter (56) B. p. 179, Pl. xii. figs. 6, 7; Solms-Laubach (96) B. p. 52,
Pl. ii. figs. 11, 13(?).
[512] Unger and Richter, Pl. xii. figs. 3, 4; Solms-Laubach (96) B. Pl. xi. fig. 10.
[513] See footnote 3, p. 205.
[514] Solms (96) B. p. 53.
[515] Dawson (81) A. p. 299, Pl. xii. figs. 1–9; Solms-Laubach (91) A. pp. 173, 188.
[516] This type is represented in the Geological Survey Collection (No. 15871).
[517] For figures, see Solms-Laubach (96) B. Pl. ii.
[518] No. 15870. Unger and Richter (56) B. Pl. vii. figs. 19–21.
[519] Page 472, fig. 324.
[520] Solms-Laubach (10) p. 540.
[521] Bertrand, P. (11) p. 47.
[522] Since this account was printed my attention has been drawn by Dr Scott to a note
by Bertrand in which he considerably modifies his views. He finds that Hierogramma
[490] Scott and Jeffrey (14).
[491] κάλυμμα, a veil or covering.
[492] White (052) B. p. 384.
[493] Richter and Unger (56) B. p. 174, Pl. x. figs. 1–3; Solms-Laubach (96) B. p. 73;
Scott (12) p. 1027.
[494] Scott and Jeffrey (14) p. 326.
[495] Ibid. p. 317, Pls. 27, 28, 30, 31.
[496] Scott (02).
[497] Scott and Jeffrey (14) p. 328, refer to a specimen over 6 cm. in diameter: these
authors give several excellent figures of Kalymma.
[498] Dawson and Penhallow (91).
[499] ἐριστός, to be disputed.
[500] Zalessky (11).
[501] Scott (992).
[502] Scott (02).
[503] Scott (02) p. 336.
[504] Page 175.
[505] Scott (12) p. 1027.
[506] Tuzson (09).
[507] Unger and Richter (56) B. p. 178.
[508] Scott and Jeffrey (14) p. 364.
[509] Solms-Laubach (96) B.
[510] P. Bertrand (08).
[511] Unger and Richter (56) B. p. 179, Pl. xii. figs. 6, 7; Solms-Laubach (96) B. p. 52,
Pl. ii. figs. 11, 13(?).
[512] Unger and Richter, Pl. xii. figs. 3, 4; Solms-Laubach (96) B. Pl. xi. fig. 10.
[513] See footnote 3, p. 205.
[514] Solms (96) B. p. 53.
[515] Dawson (81) A. p. 299, Pl. xii. figs. 1–9; Solms-Laubach (91) A. pp. 173, 188.
[516] This type is represented in the Geological Survey Collection (No. 15871).
[517] For figures, see Solms-Laubach (96) B. Pl. ii.
[518] No. 15870. Unger and Richter (56) B. Pl. vii. figs. 19–21.
[519] Page 472, fig. 324.
[520] Solms-Laubach (10) p. 540.
[521] Bertrand, P. (11) p. 47.
[522] Since this account was printed my attention has been drawn by Dr Scott to a note
by Bertrand in which he considerably modifies his views. He finds that Hierogramma
Page 758
and Syncardia are probably different states of the petiole of Cladoxylon and while
agreeing with Solms-Laubach’s conclusions he has been able to add important new facts.
Bertrand has now given up the opinion that Clepsydropsis is the petiole of Cladoxylon.
For further details students should consult the preliminary note which it is hoped will be
followed by a fully illustrated memoir [Bertrand, P. (14)].
[523] Solms-Laubach (10) p. 537, Pl. iii. figs. 7, 11, 13.
[524] Bancroft (13).
[525] After the late Herr Völkel of Neurode.
[526] Solms-Laubach (10), Pl. iii. figs. 1–4.
[527] Goeppert (52) Pl. xii.
[528] Solms-Laubach (91) A. p. 164.
[529] P. Bertrand (08).
[530] The name Palaeopitys, with which Protopitys might be confused, was used by
McNab for an imperfect specimen from the Old Red Sandstone of Scotland described as
Palaeopitys Milleri; McNab (70).
[531] Kraus (92).
[532] Solms-Laubach (93).
[533] Vol. ii. p. 212, fig. 200, A, B.
[534] See page 206.
[535] In the form of the pits on the tracheids and in the structure of the medullary rays
the English species (as represented in Dr Kidston’s Collection) agrees very closely with
Goeppert’s type.
[536] Gothan (072) p. 10.
[537] Renault (79) B. p. 272, Pls. xiii, xiv.
[538] Bertrand and Renault (82); Bertrand, C. E. (89); Renault (96) A. p. 279, (93) A.
Pls. lxxiv. lxxv; Scott (09) B. p. 500. See also Scott and Maslen (10) Maslen (11) p.
409.
[539] Grand’Eury (05).
[540] Lignier (112).
[541] Renault (80).
[542] Renault (93) A. Pl. lxxiv. fig. 8.
[543] See page 270.
[544] See Vol. i. p. 76, fig. 13.
[545] See Vol. iv.
[546] For restorations, see Grand’Eury (77) A. Pl. d; good examples of foliage-shoots
are figured by Renault and Zeiller (88) A. Pls. lxvi. lxxxi.; Grand’Eury (90) A. Pl. lxiv.;
Kidston (02) B. Pl. lxiv. fig. 2.
[547] Renault (79) B. Pl. xvi. fig. 1; Lignier (132). Cf. Dolerophyllum, p. 133.
[548] Sternberg (23) A. Pl. xviii.
[549] Brongniart (49) A. p. 65.
agreeing with Solms-Laubach’s conclusions he has been able to add important new facts.
Bertrand has now given up the opinion that Clepsydropsis is the petiole of Cladoxylon.
For further details students should consult the preliminary note which it is hoped will be
followed by a fully illustrated memoir [Bertrand, P. (14)].
[523] Solms-Laubach (10) p. 537, Pl. iii. figs. 7, 11, 13.
[524] Bancroft (13).
[525] After the late Herr Völkel of Neurode.
[526] Solms-Laubach (10), Pl. iii. figs. 1–4.
[527] Goeppert (52) Pl. xii.
[528] Solms-Laubach (91) A. p. 164.
[529] P. Bertrand (08).
[530] The name Palaeopitys, with which Protopitys might be confused, was used by
McNab for an imperfect specimen from the Old Red Sandstone of Scotland described as
Palaeopitys Milleri; McNab (70).
[531] Kraus (92).
[532] Solms-Laubach (93).
[533] Vol. ii. p. 212, fig. 200, A, B.
[534] See page 206.
[535] In the form of the pits on the tracheids and in the structure of the medullary rays
the English species (as represented in Dr Kidston’s Collection) agrees very closely with
Goeppert’s type.
[536] Gothan (072) p. 10.
[537] Renault (79) B. p. 272, Pls. xiii, xiv.
[538] Bertrand and Renault (82); Bertrand, C. E. (89); Renault (96) A. p. 279, (93) A.
Pls. lxxiv. lxxv; Scott (09) B. p. 500. See also Scott and Maslen (10) Maslen (11) p.
409.
[539] Grand’Eury (05).
[540] Lignier (112).
[541] Renault (80).
[542] Renault (93) A. Pl. lxxiv. fig. 8.
[543] See page 270.
[544] See Vol. i. p. 76, fig. 13.
[545] See Vol. iv.
[546] For restorations, see Grand’Eury (77) A. Pl. d; good examples of foliage-shoots
are figured by Renault and Zeiller (88) A. Pls. lxvi. lxxxi.; Grand’Eury (90) A. Pl. lxiv.;
Kidston (02) B. Pl. lxiv. fig. 2.
[547] Renault (79) B. Pl. xvi. fig. 1; Lignier (132). Cf. Dolerophyllum, p. 133.
[548] Sternberg (23) A. Pl. xviii.
[549] Brongniart (49) A. p. 65.
Page 759
[550] Unger (50) A. p. 277.
[551] Tuzson (09) p. 18.
[552] Grand’Eury (77) A. p. 257.
[553] Schenk in Schimper and Schenk (90) A. p. 243.
[554] Endlicher (47) p. 298.
[555] Scott (12) p. 1024.
[556] Grand’Eury (05).
[557] Benson (12).
[558] Scott (12) p. 1022.
[559] Grand’Eury (77) A. p. 208.
[560] Grand’Eury (90) A. p. 321.
[561] Renault (79) A. Pl. xvi. fig. 7.
[562] Lesquereux (78) p. 318.
[563] Felix (86) A. Pl. iii. fig. 1.
[564] Renault (79) A. Pl. xvi. fig. 11 bis; Wills, L. (14).
[565] Renault (79) A. Pl. xvi. fig. 5; Stopes (03) Pl. ix. fig. 1; Lignier (132).
[566] Benson (12).
[567] Lignier (132).
[568] Germar (48) B. p. 55, Pl. xxiii.
[569] Kidston (93) A. Pl. iv. fig. 16; (02) B. Pl. lxiv. fig. 3.
[570] Kidston (93) A. p. 352.
[571] Lindley and Hutton (33) A. Pl. 95.
[572] Howse (88) p. 112, fig. 7.
[573] Geinitz (55) A. p. 40, Pl. xxi. figs. 7–16.
[574] Kidston (93) A. p. 355.
[575] Lesquereux (80) A. p. 537, Pl. lxxviii.
[576] Geinitz (62) p. 148, Pl. xxxv.
[577] Sternberg (23) A. Pl. xviii.
[578] Corda (45) A. Pl. xxiv. fig. 8.
[579] Feistmantel (72) p. 293.
[580] Lesquereux (78).
[581] White (99) B. p. 260, Pls. iii. xvi. xlvi.
[582] Zeiller records the same fungus on leaves of Cordaites (Noeggerathiopsis) Hislopi
from Tonkin; Zeiller (03) B. p. 151.
[583] Stopes (14) p. 82.
[584] Schmalhausen (87) Pl. vi.
[585] Grand’Eury (77) A. p. 218, Pl. xx. figs. 1–4.
[551] Tuzson (09) p. 18.
[552] Grand’Eury (77) A. p. 257.
[553] Schenk in Schimper and Schenk (90) A. p. 243.
[554] Endlicher (47) p. 298.
[555] Scott (12) p. 1024.
[556] Grand’Eury (05).
[557] Benson (12).
[558] Scott (12) p. 1022.
[559] Grand’Eury (77) A. p. 208.
[560] Grand’Eury (90) A. p. 321.
[561] Renault (79) A. Pl. xvi. fig. 7.
[562] Lesquereux (78) p. 318.
[563] Felix (86) A. Pl. iii. fig. 1.
[564] Renault (79) A. Pl. xvi. fig. 11 bis; Wills, L. (14).
[565] Renault (79) A. Pl. xvi. fig. 5; Stopes (03) Pl. ix. fig. 1; Lignier (132).
[566] Benson (12).
[567] Lignier (132).
[568] Germar (48) B. p. 55, Pl. xxiii.
[569] Kidston (93) A. Pl. iv. fig. 16; (02) B. Pl. lxiv. fig. 3.
[570] Kidston (93) A. p. 352.
[571] Lindley and Hutton (33) A. Pl. 95.
[572] Howse (88) p. 112, fig. 7.
[573] Geinitz (55) A. p. 40, Pl. xxi. figs. 7–16.
[574] Kidston (93) A. p. 355.
[575] Lesquereux (80) A. p. 537, Pl. lxxviii.
[576] Geinitz (62) p. 148, Pl. xxxv.
[577] Sternberg (23) A. Pl. xviii.
[578] Corda (45) A. Pl. xxiv. fig. 8.
[579] Feistmantel (72) p. 293.
[580] Lesquereux (78).
[581] White (99) B. p. 260, Pls. iii. xvi. xlvi.
[582] Zeiller records the same fungus on leaves of Cordaites (Noeggerathiopsis) Hislopi
from Tonkin; Zeiller (03) B. p. 151.
[583] Stopes (14) p. 82.
[584] Schmalhausen (87) Pl. vi.
[585] Grand’Eury (77) A. p. 218, Pl. xx. figs. 1–4.
Page 760
[586] Zeiller (06) B. p. 182, Pl. xlvi.; Grand’Eury (90) A. Pl. vii. figs. 1, 2.
[587] Lignier (132).
[588] Lesquereux (78) p. 318; (80) A. Pl. lxxvii.
[589] Cambier and Renier (10); Renier (102) Pl. 118.
[590] See postea.
[587] Lignier (132).
[588] Lesquereux (78) p. 318; (80) A. Pl. lxxvii.
[589] Cambier and Renier (10); Renier (102) Pl. 118.
[590] See postea.
Page 761
[591] Goeppert (64) A. Pl. xxii. fig. 2.
[592] Weiss, C. E. (72) p. 199.
[593] Grand’Eury (77) A. Pl. xviii.; Renault and Zeiller (88) A. Pl. lxvi.
[594] Weiss, C. E. (72) p. 195.
[595] Kidston (02) B. Pl. lxiv. fig. 2.
[596] Zeiller (80) A. p. 146, Pl. clxxv. fig. 1; Grand’Eury (77) A. p. 225; (90) A. Pl. vii.
fig. 5; Renault and Zeiller (88) A. Pl. lxvii. figs. 1, 2.
[597] Lesquereux (80) A. p. 539.
[598] Lesquereux (78) p. 322.
[599] Schmalhausen (87) Pl. vi. figs. 4–6.
[600] Grand’Eury (90) A. p. 325, Pl. vi. fig. 15.
[601] Schmalhausen (87) Pl. v. figs. 7–9.
[602] Lesquereux (80) A. p. 535, Pl. lxxxvii. figs. 2–4.
[603] Grand’Eury, loc. cit. p. 324, Pl. iv. fig. 14.
[604] Renault and Zeiller (88) A. p. 603, Pl. lxiii. fig. 6.
[605] Dawson (90) p. 3.
[606] Goeppert (452) p. 7, Pls. xxvii. xxviii.
[607] Zalessky (12) p. 36; (122). See also Gothan (11).
[608] Kosmovsky (92).
[609] Schmalhausen (79) A. p. 32; Zeiller (96) A.
[610] Zeiller (03) B. For other references see Seward (14).
[611] Wieland (13).
[612] McCoy (74) B. Decade iv. p. 22.
[613] Wieland (13).
[614] Newberry (88) p. 350.
[615] Feistmantel (792) p. 23; (802).
[616] Bunbury (61) B. p. 334.
[617] Mellor and Leslie (06) B.
[618] White (08) B. p. 549.
[619] Arber (03) B. p. 178, gives references to other authors.
[620] Zeiller (03) B. p. 149, Pl. xl.
[621] Zalessky (12).
[622] White (08) B. p. 549.
[623] Seward and Leslie (08) B. p. 120.
[592] Weiss, C. E. (72) p. 199.
[593] Grand’Eury (77) A. Pl. xviii.; Renault and Zeiller (88) A. Pl. lxvi.
[594] Weiss, C. E. (72) p. 195.
[595] Kidston (02) B. Pl. lxiv. fig. 2.
[596] Zeiller (80) A. p. 146, Pl. clxxv. fig. 1; Grand’Eury (77) A. p. 225; (90) A. Pl. vii.
fig. 5; Renault and Zeiller (88) A. Pl. lxvii. figs. 1, 2.
[597] Lesquereux (80) A. p. 539.
[598] Lesquereux (78) p. 322.
[599] Schmalhausen (87) Pl. vi. figs. 4–6.
[600] Grand’Eury (90) A. p. 325, Pl. vi. fig. 15.
[601] Schmalhausen (87) Pl. v. figs. 7–9.
[602] Lesquereux (80) A. p. 535, Pl. lxxxvii. figs. 2–4.
[603] Grand’Eury, loc. cit. p. 324, Pl. iv. fig. 14.
[604] Renault and Zeiller (88) A. p. 603, Pl. lxiii. fig. 6.
[605] Dawson (90) p. 3.
[606] Goeppert (452) p. 7, Pls. xxvii. xxviii.
[607] Zalessky (12) p. 36; (122). See also Gothan (11).
[608] Kosmovsky (92).
[609] Schmalhausen (79) A. p. 32; Zeiller (96) A.
[610] Zeiller (03) B. For other references see Seward (14).
[611] Wieland (13).
[612] McCoy (74) B. Decade iv. p. 22.
[613] Wieland (13).
[614] Newberry (88) p. 350.
[615] Feistmantel (792) p. 23; (802).
[616] Bunbury (61) B. p. 334.
[617] Mellor and Leslie (06) B.
[618] White (08) B. p. 549.
[619] Arber (03) B. p. 178, gives references to other authors.
[620] Zeiller (03) B. p. 149, Pl. xl.
[621] Zalessky (12).
[622] White (08) B. p. 549.
[623] Seward and Leslie (08) B. p. 120.
Page 762
[624] Zalessky (13) p. 20, Pl. ii. figs. 4–6.
[625] The results have not yet been published (September, 1915).
[626] Zalessky (13) p. 23, Pls. i. fig. 4; ii. figs. 7, 9; iii. figs. 3, 5–8, 10, 11.
[627] Schmalhausen (79) A. p. 29.
[628] Zeiller (96) A. (02).
[629] Schmalhausen (87) B. p. 37.
[630] Feistmantel (792) p. 26; Arber (05) B. p. 186.
[631] Feistmantel (82) p. 42, Pl. xiv.; White (08) B. Pl. x; Schmalhausen (87) B.
[632] Schmalhausen (87) B. Pls. v., vii.
[633] Zeiller (03) B. Pl. xl.
[634] Feistmantel (792) Pl. xiii. fig. 6.
[635] Feistmantel (90) A. Pl. xxi. figs. 1, 2.
[636] Zeiller (02) B. Pl. vii. fig. 6.
[637] Renault (79) B. p. 287.
[638] Renault and Zeiller (88) A. Pl. lxxi.
[639] Harshberger (98).
[640] Artis (25) A. Pl. viii.
[641] Sternberg (38) A. p. 192. For examples of Artisia, see also Renault and Zeiller (88)
A. p. 581, Pl. lxv.
[642] Zeiller (06) B. p. 189.
[643] Dawson (46) p. 135.
[644] Williamson (51).
[645] Lignier (95) Pl. vii. fig. 13.
[646] Gothan (05) p. 28.
[647] See page 199.
[648] Renault (79) B. p. 288.
[649] See page 295.
[650] Felix (86) A. p. 56; Knowlton (90); Zeiller (95) B. p. 627; Penhallow (00) p. 54.
[651] Potonié (02) p. 229.
[652] Gothan (05) p. 13.
[653] Gothan (05) p. 15.
[654] Sterzel (03).
[655] See Chap. xlv.
[656] Williamson (77) A. p. 226, Pls. vii.–ix.; (80) A. p. 516, Pl. xx. fig. 16; (832) A. p.
470.
[657] Thomson and Allin (12); Thomson (13) p. 14.
[658] Penhallow (00) p. 76.
[625] The results have not yet been published (September, 1915).
[626] Zalessky (13) p. 23, Pls. i. fig. 4; ii. figs. 7, 9; iii. figs. 3, 5–8, 10, 11.
[627] Schmalhausen (79) A. p. 29.
[628] Zeiller (96) A. (02).
[629] Schmalhausen (87) B. p. 37.
[630] Feistmantel (792) p. 26; Arber (05) B. p. 186.
[631] Feistmantel (82) p. 42, Pl. xiv.; White (08) B. Pl. x; Schmalhausen (87) B.
[632] Schmalhausen (87) B. Pls. v., vii.
[633] Zeiller (03) B. Pl. xl.
[634] Feistmantel (792) Pl. xiii. fig. 6.
[635] Feistmantel (90) A. Pl. xxi. figs. 1, 2.
[636] Zeiller (02) B. Pl. vii. fig. 6.
[637] Renault (79) B. p. 287.
[638] Renault and Zeiller (88) A. Pl. lxxi.
[639] Harshberger (98).
[640] Artis (25) A. Pl. viii.
[641] Sternberg (38) A. p. 192. For examples of Artisia, see also Renault and Zeiller (88)
A. p. 581, Pl. lxv.
[642] Zeiller (06) B. p. 189.
[643] Dawson (46) p. 135.
[644] Williamson (51).
[645] Lignier (95) Pl. vii. fig. 13.
[646] Gothan (05) p. 28.
[647] See page 199.
[648] Renault (79) B. p. 288.
[649] See page 295.
[650] Felix (86) A. p. 56; Knowlton (90); Zeiller (95) B. p. 627; Penhallow (00) p. 54.
[651] Potonié (02) p. 229.
[652] Gothan (05) p. 13.
[653] Gothan (05) p. 15.
[654] Sterzel (03).
[655] See Chap. xlv.
[656] Williamson (77) A. p. 226, Pls. vii.–ix.; (80) A. p. 516, Pl. xx. fig. 16; (832) A. p.
470.
[657] Thomson and Allin (12); Thomson (13) p. 14.
[658] Penhallow (00) p. 76.
Page 763
[659] White (08) B. p. 583.
[660] Seward and Ford (06) B. p. 341.
[661] Penhallow (00) p. 64, fig. 12.
[662] See page 293.
[663] Gothan (05) p. 16.
[664] See page 259.
[665] Thomson (13) p. 19.
[666] Arber (05) B. p. 191. See postea, p. 255.
[667] An account of this wood is being published by Miss Holden.
[668] Matthew (10) p. 77, Pls. i., ii.
[669] Goeppert and Stenzel (88) p. 10.
[670] Penhallow (00) p. 67.
[671] Sterzel (00); (03); (12). See also Goeppert (80).
[672] Goeppert and Stenzel (88) Pl. ii. fig. 14.
[673] Witham (33) A.
[674] Scott (09) B. p. 528, fig. 190. See also Penhallow (00) p. 62, with references to
literature.
[675] Thomson (13) p. 19.
[676] Ibid. p. 16.
[677] Felix (86) A. Pl. v. fig. 4.
[678] White (08) B. p. 579, Pl. xiii.
[679] Ibid. p. 583, Pl. xiv.
[680] Arber (05) B. p. 191, figs. 40–43.
[681] Crié (89).
[682] Shirley (98) p. 14; Arber (05) B. p. 201.
[683] Warren (12).
[684] Dawson (632).
[685] Penhallow (00) figs. 13, 14, 17.
[686] Arber, E. A. N. (132).
[687] Zeiller (95) B. p. 619, Pl. ix. figs. 8–19.
[688] White (08) B. p. 577.
[689] Renault (96) A. p. 350; (93) A. Pl. lxxvii.
[690] Gothan (10) p. 5, Pl. i. figs. 1–3.
[691] Nathorst (113) p. 222.
[692] Renault (96).
[693] Williamson (722).
[694] Williamson (74) A. p. 67.
[660] Seward and Ford (06) B. p. 341.
[661] Penhallow (00) p. 64, fig. 12.
[662] See page 293.
[663] Gothan (05) p. 16.
[664] See page 259.
[665] Thomson (13) p. 19.
[666] Arber (05) B. p. 191. See postea, p. 255.
[667] An account of this wood is being published by Miss Holden.
[668] Matthew (10) p. 77, Pls. i., ii.
[669] Goeppert and Stenzel (88) p. 10.
[670] Penhallow (00) p. 67.
[671] Sterzel (00); (03); (12). See also Goeppert (80).
[672] Goeppert and Stenzel (88) Pl. ii. fig. 14.
[673] Witham (33) A.
[674] Scott (09) B. p. 528, fig. 190. See also Penhallow (00) p. 62, with references to
literature.
[675] Thomson (13) p. 19.
[676] Ibid. p. 16.
[677] Felix (86) A. Pl. v. fig. 4.
[678] White (08) B. p. 579, Pl. xiii.
[679] Ibid. p. 583, Pl. xiv.
[680] Arber (05) B. p. 191, figs. 40–43.
[681] Crié (89).
[682] Shirley (98) p. 14; Arber (05) B. p. 201.
[683] Warren (12).
[684] Dawson (632).
[685] Penhallow (00) figs. 13, 14, 17.
[686] Arber, E. A. N. (132).
[687] Zeiller (95) B. p. 619, Pl. ix. figs. 8–19.
[688] White (08) B. p. 577.
[689] Renault (96) A. p. 350; (93) A. Pl. lxxvii.
[690] Gothan (10) p. 5, Pl. i. figs. 1–3.
[691] Nathorst (113) p. 222.
[692] Renault (96).
[693] Williamson (722).
[694] Williamson (74) A. p. 67.
Page 764
[695] Renault (79) B. p. 294, Pl. xv. figs. 13–17. See also Scott (09) B. p. 531, fig. 191.
[696] Osborne (09).
[697] Williamson (74) A. Pl. ix. fig. 56.
[698] Mellor and Leslie (06) B.
[699] Brongniart (22) A. Pl. xiv. fig. 7.
[700] Renault and Zeiller (90) A. p. 593.
[701] Lindley and Hutton (33) A. Pl. lxxxii.
[702] Morris (40) A. Pl. xxviii. fig. 5.
[703] Carruthers (723) B.
[704] Goeppert (65) p. 152.
[705] Weiss, C. E. (69) B. p. 201.
[706] Grand’Eury (77) A. p. 299; (90) A. p. 330.
[707] Zeiller (002) B. p. 211.
[708] See Chap. xxxv.
[709] Lindley and Hutton (33) A. Pl. lxxxii.; Carruthers (723) B. p. 7; Kidston (03) B. p.
782; (11) p. 235.
[710] Renault and Zeiller (90) A. p. 592, Pl. lxxiii. fig. 31.
[711] Ettingshausen (522) p. 5, Pl. v.
[712] Renault (79) B. p. 304.
[713] Bertrand, C. E. (11).
[714] Scott and Maslen (10); Scott (12).
[715] Scott (09) B. pp. 511, 526.
[716] Maslen (11).
[717] Maslen (11) Pl. xxxiii. figs. 3–5.
[718] Scott (12) p. 1012, Pls. lxxxvii., lxxxix.
[719] Scott (12) p. 1017, Pls. lxxxviii., xc.q
[720] Benson (12).
[721] See page 270.
[722] See page 132.
[723] See page 238.
[724] Stopes (14); Kidston (02) B. p. 363.
[725] Zeiller (002) B. p. 213.
[726] Schimper and Mougeot (44) A. p. 42, Pl. xxi.
[727] Fliche (10) p. 218, Pl. xx. fig. 2.
[728] See postea.
[729] Wills, L. T. (10), p. 296, fig. 26.
[730] Arber (07) Pls. xvii.–xix.
[696] Osborne (09).
[697] Williamson (74) A. Pl. ix. fig. 56.
[698] Mellor and Leslie (06) B.
[699] Brongniart (22) A. Pl. xiv. fig. 7.
[700] Renault and Zeiller (90) A. p. 593.
[701] Lindley and Hutton (33) A. Pl. lxxxii.
[702] Morris (40) A. Pl. xxviii. fig. 5.
[703] Carruthers (723) B.
[704] Goeppert (65) p. 152.
[705] Weiss, C. E. (69) B. p. 201.
[706] Grand’Eury (77) A. p. 299; (90) A. p. 330.
[707] Zeiller (002) B. p. 211.
[708] See Chap. xxxv.
[709] Lindley and Hutton (33) A. Pl. lxxxii.; Carruthers (723) B. p. 7; Kidston (03) B. p.
782; (11) p. 235.
[710] Renault and Zeiller (90) A. p. 592, Pl. lxxiii. fig. 31.
[711] Ettingshausen (522) p. 5, Pl. v.
[712] Renault (79) B. p. 304.
[713] Bertrand, C. E. (11).
[714] Scott and Maslen (10); Scott (12).
[715] Scott (09) B. pp. 511, 526.
[716] Maslen (11).
[717] Maslen (11) Pl. xxxiii. figs. 3–5.
[718] Scott (12) p. 1012, Pls. lxxxvii., lxxxix.
[719] Scott (12) p. 1017, Pls. lxxxviii., xc.q
[720] Benson (12).
[721] See page 270.
[722] See page 132.
[723] See page 238.
[724] Stopes (14); Kidston (02) B. p. 363.
[725] Zeiller (002) B. p. 213.
[726] Schimper and Mougeot (44) A. p. 42, Pl. xxi.
[727] Fliche (10) p. 218, Pl. xx. fig. 2.
[728] See postea.
[729] Wills, L. T. (10), p. 296, fig. 26.
[730] Arber (07) Pls. xvii.–xix.
Page 765
[731] Seward (04) B. p. 111.
[732] Arber (092).
[733] Fliche (10) p. 264, Pl. xxvii. fig. 2.
[734] Halle (10).
[735] Salfeld (09) B. p. 26.
[736] Saporta (94) B. p. 216, Pl. xxxviii.
[737] Velenovský (85) B. p. 1, Pls. i., iv.
[738] See postea.
[739] Heer (76) A. p. 86, Pl. xxx. fig. 10.
[740] Leuthardt (03), p. 6, Pl. i.
[741] Fliche (10) p. 175, Pls. xvi., xvii.
[742] Compter, G. (94), Pl. iv. fig. 9.
[743] Phillips (71) p. 169.
[744] Seward (04) B. p. 110; Arber, E. A. N. (07) p. 117.
[745] Zigno (85), p. 7, Pl. xxvi.
[746] Velenovský (85) B. Pls. i.–iii.
[747] Stopes and Fujii (10) p. 16, Pl. iii. figs. 14–16.
[748] See postea.
[749] Schenk (71) p. 20, Pl. vii. fig. 4.
[750] Zeiller (052) p. 17, Pl. vii. figs. 8–11.
[751] Renault and Zeiller (90) A. p. 627, Pl. lxix. figs. 1–4.
[752] White (99) B. p. 271.
[753] Witham (33) A. pp. 37, 71.
[754] Witham (30).
[755] Goeppert (81) p. 403.
[756] Endlicher (47) p. 297.
[757] Scott (02) p. 346.
[758] See footnote p. 288.
[759] Scott (992); Witham (33) A. Pls. iii.–viii. xvi.
[760] Scott (02), p. 346, Pls. i., ii., v., vi.
[761] Scott (02) p. 355.
[762] Witham (33) A. Pl. viii. fig. 2.
[763] Ibid. p. 39, Pls. viii., xvi.; Scott (02) p. 355, Pls. ii., vi.
[764] Since this chapter was written Prof. W. T. Gordon has kindly supplied the
following summary of his unpublished work on the genus Pitys.
‘The re-examination of Pitys primaeva and P. antiqua in the light of the structure
exhibited by numerous specimens of a new species recently discovered in
Haddingtonshire has shown that all three types are similar as regards the structure of the
[732] Arber (092).
[733] Fliche (10) p. 264, Pl. xxvii. fig. 2.
[734] Halle (10).
[735] Salfeld (09) B. p. 26.
[736] Saporta (94) B. p. 216, Pl. xxxviii.
[737] Velenovský (85) B. p. 1, Pls. i., iv.
[738] See postea.
[739] Heer (76) A. p. 86, Pl. xxx. fig. 10.
[740] Leuthardt (03), p. 6, Pl. i.
[741] Fliche (10) p. 175, Pls. xvi., xvii.
[742] Compter, G. (94), Pl. iv. fig. 9.
[743] Phillips (71) p. 169.
[744] Seward (04) B. p. 110; Arber, E. A. N. (07) p. 117.
[745] Zigno (85), p. 7, Pl. xxvi.
[746] Velenovský (85) B. Pls. i.–iii.
[747] Stopes and Fujii (10) p. 16, Pl. iii. figs. 14–16.
[748] See postea.
[749] Schenk (71) p. 20, Pl. vii. fig. 4.
[750] Zeiller (052) p. 17, Pl. vii. figs. 8–11.
[751] Renault and Zeiller (90) A. p. 627, Pl. lxix. figs. 1–4.
[752] White (99) B. p. 271.
[753] Witham (33) A. pp. 37, 71.
[754] Witham (30).
[755] Goeppert (81) p. 403.
[756] Endlicher (47) p. 297.
[757] Scott (02) p. 346.
[758] See footnote p. 288.
[759] Scott (992); Witham (33) A. Pls. iii.–viii. xvi.
[760] Scott (02), p. 346, Pls. i., ii., v., vi.
[761] Scott (02) p. 355.
[762] Witham (33) A. Pl. viii. fig. 2.
[763] Ibid. p. 39, Pls. viii., xvi.; Scott (02) p. 355, Pls. ii., vi.
[764] Since this chapter was written Prof. W. T. Gordon has kindly supplied the
following summary of his unpublished work on the genus Pitys.
‘The re-examination of Pitys primaeva and P. antiqua in the light of the structure
exhibited by numerous specimens of a new species recently discovered in
Haddingtonshire has shown that all three types are similar as regards the structure of the
Page 766
primary wood. In each case the primary cylinder is comparable with that in Archaeopitys
Eastmanii [see p. 290], i.e., there are medullary as well as circummedullary xylem-
strands. In certain specimens of the new species, Pitys Dayii, the bark and leaves are
preserved and thus the details of leaf-trace emission from the stem have been
determined. The leaves are short and stout and taper gradually to a point, quite distinct
from the long, thin, spatulate Cordaitean foliage. The internal structure of the leaf
renders it easily distinguishable from the Cordaites type while it tends to accentuate the
possible relationship of Pitys with the Lyginodendreae.’
[765] Williamson (78) A. p. 352, Pl. xxv. figs. 90–92; Williamson and Scott (95) p. 770;
Seward (972) p. 80.
[766] Witham (31) A.
[767] Goeppert (50) p. 251; (81).
[768] Brongniart (49) A. 77.
[769] Scott (02) p. 354.
[770] Scott and Jeffrey (14) p. 345, Pl. xxxi. figs. 31–36; text-figs. 4, 5.
[771] Zalessky (09); (11) p. 29, Pl. iv.
[772] Zalessky (11) Pl. iv. fig. 3.
[773] Scott (12) p. 1024.
[774] Elkins and Wieland (14).
[775] Penhallow (00) pp. 64, Pl. xii.
[776] Zalessky (112) p. 13, figs. 1–4.
[777] See page 295.
[778] Zalessky (11) p. 28.
[779] Williamson (80) A. p. 516, Pl. xx. fig. 60.
[780] Scott (02) p. 357, Pls. ii., vi.
[781] Scott (12) p. 1028.
[782] Goeppert (452) p. 11, Pls. xxix.–xxxv.; Zalessky (11).
[783] Goeppert and Stenzel (88) p. 33, Pls. v., vi.
[784] Kraus in Schimper (72) A. p. 381.
[785] Seward (14) p. 17, Pls. iv.–viii.
[786] Scott (12).
[787] See page 175.
[788] De Bary (84) A. p. 492; Grossenbacher (15).
[789] See Scott, Nature, August 26, 1915.
[790] See Vol. ii. p. 56.
[791] Oliver (06) p. 726.
[792] Hooker and Binney (55).
[793] Oliver (03).
[794] Worsdell (05) p. 58; Salisbury (14) p. 67.
Eastmanii [see p. 290], i.e., there are medullary as well as circummedullary xylem-
strands. In certain specimens of the new species, Pitys Dayii, the bark and leaves are
preserved and thus the details of leaf-trace emission from the stem have been
determined. The leaves are short and stout and taper gradually to a point, quite distinct
from the long, thin, spatulate Cordaitean foliage. The internal structure of the leaf
renders it easily distinguishable from the Cordaites type while it tends to accentuate the
possible relationship of Pitys with the Lyginodendreae.’
[765] Williamson (78) A. p. 352, Pl. xxv. figs. 90–92; Williamson and Scott (95) p. 770;
Seward (972) p. 80.
[766] Witham (31) A.
[767] Goeppert (50) p. 251; (81).
[768] Brongniart (49) A. 77.
[769] Scott (02) p. 354.
[770] Scott and Jeffrey (14) p. 345, Pl. xxxi. figs. 31–36; text-figs. 4, 5.
[771] Zalessky (09); (11) p. 29, Pl. iv.
[772] Zalessky (11) Pl. iv. fig. 3.
[773] Scott (12) p. 1024.
[774] Elkins and Wieland (14).
[775] Penhallow (00) pp. 64, Pl. xii.
[776] Zalessky (112) p. 13, figs. 1–4.
[777] See page 295.
[778] Zalessky (11) p. 28.
[779] Williamson (80) A. p. 516, Pl. xx. fig. 60.
[780] Scott (02) p. 357, Pls. ii., vi.
[781] Scott (12) p. 1028.
[782] Goeppert (452) p. 11, Pls. xxix.–xxxv.; Zalessky (11).
[783] Goeppert and Stenzel (88) p. 33, Pls. v., vi.
[784] Kraus in Schimper (72) A. p. 381.
[785] Seward (14) p. 17, Pls. iv.–viii.
[786] Scott (12).
[787] See page 175.
[788] De Bary (84) A. p. 492; Grossenbacher (15).
[789] See Scott, Nature, August 26, 1915.
[790] See Vol. ii. p. 56.
[791] Oliver (06) p. 726.
[792] Hooker and Binney (55).
[793] Oliver (03).
[794] Worsdell (05) p. 58; Salisbury (14) p. 67.
Page 767
[795] Brongniart (81) p. 31.
[796] For an account of the work of this author see Lang in Oliver (13) p. 178.
[797] See Scott (09) B. p. 543.
[798] Mirande (05).
[799] For definition of Cardiocarpus, see page 338.
[800] See page 25.
[801] Solms-Laubach (91) A. p. 118.
[802] Goeppert (65) p. 177, Pl. xxvi. figs. 27, 28.
[803] Williamson (77) B. p. 262.
[804] Zeiller (88) A. p. 642.
[805] Brongniart (74).
[806] Brongniart (81).
[807] Oliver (04) B. p. 389.
[808] Affourtit and La Rivière (15).
[809] Nathorst (14) p. 32.
[810] See page 173.
[811] Salisbury (14) p. 71.
[812] Salisbury (14).
[813] Oliver (04) B. p. 392.
[814] Oliver (07).
[815] Arber, A. (10) p. 505.
[816] See Chapter xxxi.
[817] Oliver and Salisbury (11).
[818] Salisbury (14) p. 67.
[819] Oliver (09) p. 99.
[820] Nathorst (14) p. 29.
[821] φυσάω, to blow; φϋσα, a bladder.
[822] Williamson (76) p. 160; (17) B. p. 241, Pl. xi. figs. 77, 78; Pl. xii. fig. 79.
[823] Oliver (09); Oliver and Salisbury (11) passim; Salisbury (14) p. 74.
[824] Williamson (80) A. Pl. xvii. figs. 24–28; (832) A. Pl. xxxi. fig. 27 (called in this
case Sporocarpon anomalum, no doubt a slip of the pen).
[825] Oliver (09) p. 75.
[826] Williamson (76) p. 160.
[827] Oliver (09) p. 106.
[828] Lang (00) p. 288.
[829] Burlingame (15) p. 19.
[830] Gordon, W. T. (10).
[796] For an account of the work of this author see Lang in Oliver (13) p. 178.
[797] See Scott (09) B. p. 543.
[798] Mirande (05).
[799] For definition of Cardiocarpus, see page 338.
[800] See page 25.
[801] Solms-Laubach (91) A. p. 118.
[802] Goeppert (65) p. 177, Pl. xxvi. figs. 27, 28.
[803] Williamson (77) B. p. 262.
[804] Zeiller (88) A. p. 642.
[805] Brongniart (74).
[806] Brongniart (81).
[807] Oliver (04) B. p. 389.
[808] Affourtit and La Rivière (15).
[809] Nathorst (14) p. 32.
[810] See page 173.
[811] Salisbury (14) p. 71.
[812] Salisbury (14).
[813] Oliver (04) B. p. 392.
[814] Oliver (07).
[815] Arber, A. (10) p. 505.
[816] See Chapter xxxi.
[817] Oliver and Salisbury (11).
[818] Salisbury (14) p. 67.
[819] Oliver (09) p. 99.
[820] Nathorst (14) p. 29.
[821] φυσάω, to blow; φϋσα, a bladder.
[822] Williamson (76) p. 160; (17) B. p. 241, Pl. xi. figs. 77, 78; Pl. xii. fig. 79.
[823] Oliver (09); Oliver and Salisbury (11) passim; Salisbury (14) p. 74.
[824] Williamson (80) A. Pl. xvii. figs. 24–28; (832) A. Pl. xxxi. fig. 27 (called in this
case Sporocarpon anomalum, no doubt a slip of the pen).
[825] Oliver (09) p. 75.
[826] Williamson (76) p. 160.
[827] Oliver (09) p. 106.
[828] Lang (00) p. 288.
[829] Burlingame (15) p. 19.
[830] Gordon, W. T. (10).
Page 768
[831] κώνοϛ, a cone.
[832] Williamson (77) B. p. 241, Pls. xi., xii.e
[833] Page 79.
[834] Oliver and Salisbury (11).
[835] For a detailed account of the plinth see Oliver and Salisbury (11).
[836] Page 27.
[837] Page 55.
[838] Renault (84) Pls. xix.–xxii.
[839] Saporta and Marion (85) p. 181.
[840] Oliver and Salisbury (11).
[841] Renault (96) A. p. 85, Pl. xlii.
[842] Renault and Zeiller (88) A. p. 640, Pls. 72, 82.
[843] Grand’Eury (90) A. Pl. vi. fig. 6.
[844] Depape and Carpentier (13) Pl. xii. figs. 1–3.
[845] Kidston (90) p. 64.
[846] Oliver (02) p. 146.
[847] Kershaw (09).
[848] Oliver (04) B. p. 376.
[849] Renault (96) A. p. 272.
[850] Arber, E. A. N. (14) p. 103, Pl. viii. figs. 48–50.
[851] Brongniart (81) Pl. B. fig. 3.
[852] Grand’Eury (77) A. Pl. xv. fig. 1.
[853] Newberry (73).
[854] Ibid. Pl. xlii. fig. 8.
[855] Page 123.
[856] Oliver (042) B. See also Renault (96) A. p. 398.
[857] Zeiller (88) A. p. 652, Pl. 94, fig. 17.
[858] Salisbury (14).
[859] Brongniart (74) p. 252, Pl. xxii. figs. 6–8.
[860] Oliver (04) B. p. 391.
[861] Renault (96) A. p. 404.
[862] Kidston (14) p. 157.
[863] πτύξ, a plate or fold.
[864] Brongniart (74) p. 253, Pl. xxii. figs. 9–11; (81) p. 26.
[865] Ibid. p. 254, Pl. xxii. figs. 12–14; (81) p. 26.
[866] Williamson (77) B. p. 253.
[867] See page 356.
[832] Williamson (77) B. p. 241, Pls. xi., xii.e
[833] Page 79.
[834] Oliver and Salisbury (11).
[835] For a detailed account of the plinth see Oliver and Salisbury (11).
[836] Page 27.
[837] Page 55.
[838] Renault (84) Pls. xix.–xxii.
[839] Saporta and Marion (85) p. 181.
[840] Oliver and Salisbury (11).
[841] Renault (96) A. p. 85, Pl. xlii.
[842] Renault and Zeiller (88) A. p. 640, Pls. 72, 82.
[843] Grand’Eury (90) A. Pl. vi. fig. 6.
[844] Depape and Carpentier (13) Pl. xii. figs. 1–3.
[845] Kidston (90) p. 64.
[846] Oliver (02) p. 146.
[847] Kershaw (09).
[848] Oliver (04) B. p. 376.
[849] Renault (96) A. p. 272.
[850] Arber, E. A. N. (14) p. 103, Pl. viii. figs. 48–50.
[851] Brongniart (81) Pl. B. fig. 3.
[852] Grand’Eury (77) A. Pl. xv. fig. 1.
[853] Newberry (73).
[854] Ibid. Pl. xlii. fig. 8.
[855] Page 123.
[856] Oliver (042) B. See also Renault (96) A. p. 398.
[857] Zeiller (88) A. p. 652, Pl. 94, fig. 17.
[858] Salisbury (14).
[859] Brongniart (74) p. 252, Pl. xxii. figs. 6–8.
[860] Oliver (04) B. p. 391.
[861] Renault (96) A. p. 404.
[862] Kidston (14) p. 157.
[863] πτύξ, a plate or fold.
[864] Brongniart (74) p. 253, Pl. xxii. figs. 9–11; (81) p. 26.
[865] Ibid. p. 254, Pl. xxii. figs. 12–14; (81) p. 26.
[866] Williamson (77) B. p. 253.
[867] See page 356.
Page 769
[868] P. Bertrand (13) Pl. vii.
[869] Brongniart (74) p. 255, Pl. xxiii. figs. 1–3; (81) p. 27, Pl. C, figs. 1–3.
[870] Arber, E. A. N. (14) p. 102, Pl. vii. figs. 38–41.
[871] Kidston (14) p. 158, Pl. x. figs. 6, 7; Pl. xiv. figs. 5–9.
[872] Brongniart (74) p. 249, Pl. xxii. figs. 4, 5; (81) Pls. xvii.–xxi.
[873] Renault (96) A. p. 389, Pls. 83, 84.
[874] Oliver (02).
[875] Grand’Eury (04).
[876] Grand’Eury (90) A. Pl. viii. fig. 3; (77) A. Pl. xvi. fig. 5.
[877] Renault and Zeiller (88) A. Pl. 73.
[878] Zeiller (06) B. p. 229.
[879] Kidston (92) p. 8.
[880] Arber, E. A. N. (14) p. 91, Pl. vii. fig. 28.
[881] See page 364.
[882] White (99) B. p. 267; Lesquereux (79) A. Pl. 85, fig. 21.
[883] Brongniart (74) p. 259, Pl. xxiii. figs. 12–15; (81) p. 29, Pl. xvi.
[884] Renault (802).
[885] Oliver (04) B.
[886] Russow (72) Pls. iii., iv.
[887] στέφανοϛ, a crown.
[888] Oliver (04) B. p. 395.
[889] Brongniart (81) Pl. xvi. figs. 4, 6.
[890] Ibid. p. 373, Pl. xlii. figs. 17–20; xliv. figs. 36–43.
[891] λόφοϛ, a ridge.
[892] Brongniart (74) p. 256, Pl. xxiii. figs. 6–8; (81) Pl. C, figs. 6–8.
[893] Oliver (042) B. Pl. ii. figs. 5–10; (07) fig. 1.
[894] Scott and Maslen (07) Pl. xiii. fig. 19.
[895] Salisbury (14).
[896] κώδων, a bell.
[897] Brongniart (74) p. 257, Pl. xxiii. figs. 9–12; (81) p. 28, Pl. C, figs. 9–12.
[898] Renault (93) A. Pl. lxxxvii.; (96) A. p. 393.
[899] Renault and Zeiller (88) A. p. 659, Pl. 83, figs. 10–26.
[900] Grand’Eury (77) A. p. 184, Pl. xv. fig. 5; (90) A. p. 311, Pl. iii. fig. 6.
[901] Zeiller (06) B. p. 227.
[902] See also Grand’Eury (052) B.
[903] Brongniart (74) p. 260, Pl. xxiii. pp. 16–18; (81) p. 30.
[904] Renault 96 A. p. 272.
[869] Brongniart (74) p. 255, Pl. xxiii. figs. 1–3; (81) p. 27, Pl. C, figs. 1–3.
[870] Arber, E. A. N. (14) p. 102, Pl. vii. figs. 38–41.
[871] Kidston (14) p. 158, Pl. x. figs. 6, 7; Pl. xiv. figs. 5–9.
[872] Brongniart (74) p. 249, Pl. xxii. figs. 4, 5; (81) Pls. xvii.–xxi.
[873] Renault (96) A. p. 389, Pls. 83, 84.
[874] Oliver (02).
[875] Grand’Eury (04).
[876] Grand’Eury (90) A. Pl. viii. fig. 3; (77) A. Pl. xvi. fig. 5.
[877] Renault and Zeiller (88) A. Pl. 73.
[878] Zeiller (06) B. p. 229.
[879] Kidston (92) p. 8.
[880] Arber, E. A. N. (14) p. 91, Pl. vii. fig. 28.
[881] See page 364.
[882] White (99) B. p. 267; Lesquereux (79) A. Pl. 85, fig. 21.
[883] Brongniart (74) p. 259, Pl. xxiii. figs. 12–15; (81) p. 29, Pl. xvi.
[884] Renault (802).
[885] Oliver (04) B.
[886] Russow (72) Pls. iii., iv.
[887] στέφανοϛ, a crown.
[888] Oliver (04) B. p. 395.
[889] Brongniart (81) Pl. xvi. figs. 4, 6.
[890] Ibid. p. 373, Pl. xlii. figs. 17–20; xliv. figs. 36–43.
[891] λόφοϛ, a ridge.
[892] Brongniart (74) p. 256, Pl. xxiii. figs. 6–8; (81) Pl. C, figs. 6–8.
[893] Oliver (042) B. Pl. ii. figs. 5–10; (07) fig. 1.
[894] Scott and Maslen (07) Pl. xiii. fig. 19.
[895] Salisbury (14).
[896] κώδων, a bell.
[897] Brongniart (74) p. 257, Pl. xxiii. figs. 9–12; (81) p. 28, Pl. C, figs. 9–12.
[898] Renault (93) A. Pl. lxxxvii.; (96) A. p. 393.
[899] Renault and Zeiller (88) A. p. 659, Pl. 83, figs. 10–26.
[900] Grand’Eury (77) A. p. 184, Pl. xv. fig. 5; (90) A. p. 311, Pl. iii. fig. 6.
[901] Zeiller (06) B. p. 227.
[902] See also Grand’Eury (052) B.
[903] Brongniart (74) p. 260, Pl. xxiii. pp. 16–18; (81) p. 30.
[904] Renault 96 A. p. 272.
Page 770
[905] Brongniart (74) p. 256, Pl. xxiii. figs. 4, 5; (81) p. 27, Pl. C, figs. 4, 5.
[906] ἔριον, wool.
[907] Grand’Eury (90) A. p. 308, Pls. iv. fig. 12, vi. fig. 5.
[908] See page 264.
[909] Brongniart (28) A. p. 87.
[910] Brongniart (74) p. 245 (81).
[911] Geinitz (62) p. 150; Kidston (11) p. 240; Geinitz (55) A. Pl. xxi. figs. 7–16.
[912] Kidston (94) B. p. 263.
[913] Renault (802), p. 102.
[914] Fiedler (57) p. 291.
[915] Brongniart (81) Pls. iv., v.
[916] Bertrand, C. E. (082).
[917] Renault (96) A. p. 385.
[918] Bertrand, C. E. (08).
[919] Fiedler (57) p. 288, Pl. xxviii.
[920] Schenk (80) p. 660.
[921] Ward (88) p. 802.
[922] Goeppert (65) p. 177, Pl. xxviii. figs. 10, 11.
[923] Ibid. fig. 19.
[924] Heer (77) ii. Pl. xix. See also Nathorst (86) Pl. xxv. figs. 10–14.
[925] Arber, E. A. N. (14) p. 97.
[926] Arber, E. A. N. (09) Pl. i. fig. 5.
[927] Feistmantel (792)
[928] Schenk (83) A. Pl. xliv. fig. 8.
[929] Seward (972) A.
[930] White (08) B.
[931] Feistmantel (90) A. p. 164.
[932] Geinitz (80) p. 22, Pl. iii. figs. 11–15.
[933] Weiss, C. E. (72) p. 208.
[934] See page 141.
[935] White (08) B. p. 563. See also Vol. ii. p. 517.
[936] Goeppert (65) p. 146, Pl. xxvi. fig. 5.
[937] Heer (77) ii. Pl. xiv.
[938] See page 345.
[939] Brongniart (81) p. 20, Pl. ii.
[940] Bertrand, C. E. (082); (083).
[941] Bertrand, C. E. (08).
[906] ἔριον, wool.
[907] Grand’Eury (90) A. p. 308, Pls. iv. fig. 12, vi. fig. 5.
[908] See page 264.
[909] Brongniart (28) A. p. 87.
[910] Brongniart (74) p. 245 (81).
[911] Geinitz (62) p. 150; Kidston (11) p. 240; Geinitz (55) A. Pl. xxi. figs. 7–16.
[912] Kidston (94) B. p. 263.
[913] Renault (802), p. 102.
[914] Fiedler (57) p. 291.
[915] Brongniart (81) Pls. iv., v.
[916] Bertrand, C. E. (082).
[917] Renault (96) A. p. 385.
[918] Bertrand, C. E. (08).
[919] Fiedler (57) p. 288, Pl. xxviii.
[920] Schenk (80) p. 660.
[921] Ward (88) p. 802.
[922] Goeppert (65) p. 177, Pl. xxviii. figs. 10, 11.
[923] Ibid. fig. 19.
[924] Heer (77) ii. Pl. xix. See also Nathorst (86) Pl. xxv. figs. 10–14.
[925] Arber, E. A. N. (14) p. 97.
[926] Arber, E. A. N. (09) Pl. i. fig. 5.
[927] Feistmantel (792)
[928] Schenk (83) A. Pl. xliv. fig. 8.
[929] Seward (972) A.
[930] White (08) B.
[931] Feistmantel (90) A. p. 164.
[932] Geinitz (80) p. 22, Pl. iii. figs. 11–15.
[933] Weiss, C. E. (72) p. 208.
[934] See page 141.
[935] White (08) B. p. 563. See also Vol. ii. p. 517.
[936] Goeppert (65) p. 146, Pl. xxvi. fig. 5.
[937] Heer (77) ii. Pl. xiv.
[938] See page 345.
[939] Brongniart (81) p. 20, Pl. ii.
[940] Bertrand, C. E. (082); (083).
[941] Bertrand, C. E. (08).
Page 771
[942] This name has been used for a section of a genus of recent Umbelliferae but not as
a generic name (De Candolle’s ‘Prodromus,’ Pars iv. p. 105, 1830).
[943] Bertrand (083) p. 454; (082) p. 392.
[944] Brongniart (81) Pls. iv. v.
[945] Schimper (72) A. p. 208.
[946] Brongniart (81) Pl. iii.; Bertrand, C. E. (08).
[947] ῥάβδοϛ, a rod.
[948] Berger (48) p. 20, Pl. i. fig. 8.
[949] Renault and Zeiller (88) A. p. 635.
[950] Bertrand, P. (13).
[951] Arber (14) p. 103.
[952] See page 116.
[953] Arber (14) p. 87.
[954] Zeiller (922) A. Pl. xv. fig. 11.
[955] Arber (14) Pl. vii. fig. 21.
[956] In selecting a generic name for a fossil plant or part of a plant it has not been the
universal practice to avoid the use of a designation previously employed for a recent
plant. It is clearly in accordance with the Rules adopted by the International Botanical
Congress and with general convenience to avoid the employment of the same name for
two different generic types even if one is known only in a fossil state. My attention has
been called by Mr W. N. Edwards of the British Museum to the fact that the names
Platyspermum, Microspermum, and Pterospermum recently proposed by Dr Arber for
Palaeozoic seeds have previously been given to recent flowering plants. Though I have
often neglected to consult the Index Kewensis and the Genera Siphonogamarum before
proposing a ‘new’ generic term, I fully recognise the importance of avoiding the
employment of names in current use or names which have ‘lapsed into synonymy[966].’
[957] See page 361.
[958] Brongniart (74) p. 246; (81) p. 21, Pls. ix.–xi.
[959] Bertrand, C. E. (07).
[960] Grand’Eury (05).
[961] Kidston (14) Pl. xvi. figs. 6–8.
[962] Lesquereux (80) A. p. 574.
[963] White (99) B. p. 267.
[964] Grand’Eury (77) A. Pl. xv.
[965] Renault (93) A. Pl. lxxxvi.
[966] Règles internationales de la nomenclature botanique adoptées par le Cong.
Internat. Bot. de Vienne, 1905, etc. T. Briquet, Jena, 1912, p. 37.
[967] See page 314.
[968] Arber, A. (10).
[969] μίτρα, a Persian cap.
a generic name (De Candolle’s ‘Prodromus,’ Pars iv. p. 105, 1830).
[943] Bertrand (083) p. 454; (082) p. 392.
[944] Brongniart (81) Pls. iv. v.
[945] Schimper (72) A. p. 208.
[946] Brongniart (81) Pl. iii.; Bertrand, C. E. (08).
[947] ῥάβδοϛ, a rod.
[948] Berger (48) p. 20, Pl. i. fig. 8.
[949] Renault and Zeiller (88) A. p. 635.
[950] Bertrand, P. (13).
[951] Arber (14) p. 103.
[952] See page 116.
[953] Arber (14) p. 87.
[954] Zeiller (922) A. Pl. xv. fig. 11.
[955] Arber (14) Pl. vii. fig. 21.
[956] In selecting a generic name for a fossil plant or part of a plant it has not been the
universal practice to avoid the use of a designation previously employed for a recent
plant. It is clearly in accordance with the Rules adopted by the International Botanical
Congress and with general convenience to avoid the employment of the same name for
two different generic types even if one is known only in a fossil state. My attention has
been called by Mr W. N. Edwards of the British Museum to the fact that the names
Platyspermum, Microspermum, and Pterospermum recently proposed by Dr Arber for
Palaeozoic seeds have previously been given to recent flowering plants. Though I have
often neglected to consult the Index Kewensis and the Genera Siphonogamarum before
proposing a ‘new’ generic term, I fully recognise the importance of avoiding the
employment of names in current use or names which have ‘lapsed into synonymy[966].’
[957] See page 361.
[958] Brongniart (74) p. 246; (81) p. 21, Pls. ix.–xi.
[959] Bertrand, C. E. (07).
[960] Grand’Eury (05).
[961] Kidston (14) Pl. xvi. figs. 6–8.
[962] Lesquereux (80) A. p. 574.
[963] White (99) B. p. 267.
[964] Grand’Eury (77) A. Pl. xv.
[965] Renault (93) A. Pl. lxxxvi.
[966] Règles internationales de la nomenclature botanique adoptées par le Cong.
Internat. Bot. de Vienne, 1905, etc. T. Briquet, Jena, 1912, p. 37.
[967] See page 314.
[968] Arber, A. (10).
[969] μίτρα, a Persian cap.
Page 772
[970] Williamson (77) B. p. 257, Pls. xv. xvi.
[971] Bertrand, C. E. (082).
[972] Brongniart (74) p. 247, Pl. xxi. figs. 12–14; (81) p. 21, Pl. A. fig. 12; Pl. xiv;
Renault (802) p. 106, Pl. xv. figs. 12, 13; Grand’Eury (77) A. p. 239, Pl. xxvi. fig. 27.
[973] Bertrand, C. E. (072).
[974] Brongniart (74) p. 248, Pl. xxi. fig. 17; (81) p. 22, Pl. A. fig. 17; Pl. vi.
[975] Bertrand, C. E. (073) compares Leptocaryon with Diplotesta as regards various
structural features.
[976] Renault (802) p. 108.
[977] Brongniart (74) p. 249, Pl. xxi. figs. 18–20; (81) p. 23, Pl. A. figs. 18–20; Pl. xv.
[978] Oliver (03) p. 457.
[979] Bertrand, C. E. (074).
[980] Bertrand, C. E. (075).
[981] Brongniart (74) p. 247.
[982] κομψόϛ, elegant.
[983] Bertrand, C. E. (09).
[984] Dawson (66) A. p. 165, Pl. xii. fig. 74; Zeiller (06) B. p. 226; Kidston (11) p. 236.
[985] Zeiller (88) A. p. 644.
[986] White (99) B. p. 266, Pls. lxi. fig. 12, lxxii. fig. 3.
[987] Weiss, C. E. (72) Pl. xviii.
[988] Kidston (94) B. Pl. vi. fig. 3; (02) B. Pl. lviii. figs. 5, 6.
[989] Lesquereux (80) A. Pl. lxxxv. fig. 51.
[990] Helmhacher (71).
[991] Zeiller (922) A. Pl. xv. figs. 9, 10.
[992] Geinitz (75) Pl. i. figs. 10, 11; Weiss, C. E. (79) Pl. iii. figs. 17–19.
[993] Potonié (93) A. Pl. xxxii. figs. 12, 13.
[994] Stopes (14) Pl. xxv. fig. 68.
[995] Arber (14) Pl. vi. figs. 19, 20; (142) Pl. xi. fig. 5.
[996] For synonymy, see Kidston (11) p. 238, Pl. xxii. figs. 3, 3a.
[997] Fiedler (57) p. 291.
[998] Stopes (14) p. 89, Pls. xxi.–xxiii.
[999] Andrews (75) p. 425, Pl. xlvi. fig. 2.
[1000] Kidston (11) p. 239, Pl. xii. fig. 1.
[1001] Dawson (71) A. Pl. xix. fig. 219; Stopes (14) p. 92.
[1002] Fiedler (57) Pl. xxviii. fig. 36.
[1003] White (08) B. p. 567, Pl. x. fig. 11.
[1004] Newberry (73) Pl. xliii. fig. 8; Lesquereux (80) A Pl. lxxxv. figs. 36, 37.
[971] Bertrand, C. E. (082).
[972] Brongniart (74) p. 247, Pl. xxi. figs. 12–14; (81) p. 21, Pl. A. fig. 12; Pl. xiv;
Renault (802) p. 106, Pl. xv. figs. 12, 13; Grand’Eury (77) A. p. 239, Pl. xxvi. fig. 27.
[973] Bertrand, C. E. (072).
[974] Brongniart (74) p. 248, Pl. xxi. fig. 17; (81) p. 22, Pl. A. fig. 17; Pl. vi.
[975] Bertrand, C. E. (073) compares Leptocaryon with Diplotesta as regards various
structural features.
[976] Renault (802) p. 108.
[977] Brongniart (74) p. 249, Pl. xxi. figs. 18–20; (81) p. 23, Pl. A. figs. 18–20; Pl. xv.
[978] Oliver (03) p. 457.
[979] Bertrand, C. E. (074).
[980] Bertrand, C. E. (075).
[981] Brongniart (74) p. 247.
[982] κομψόϛ, elegant.
[983] Bertrand, C. E. (09).
[984] Dawson (66) A. p. 165, Pl. xii. fig. 74; Zeiller (06) B. p. 226; Kidston (11) p. 236.
[985] Zeiller (88) A. p. 644.
[986] White (99) B. p. 266, Pls. lxi. fig. 12, lxxii. fig. 3.
[987] Weiss, C. E. (72) Pl. xviii.
[988] Kidston (94) B. Pl. vi. fig. 3; (02) B. Pl. lviii. figs. 5, 6.
[989] Lesquereux (80) A. Pl. lxxxv. fig. 51.
[990] Helmhacher (71).
[991] Zeiller (922) A. Pl. xv. figs. 9, 10.
[992] Geinitz (75) Pl. i. figs. 10, 11; Weiss, C. E. (79) Pl. iii. figs. 17–19.
[993] Potonié (93) A. Pl. xxxii. figs. 12, 13.
[994] Stopes (14) Pl. xxv. fig. 68.
[995] Arber (14) Pl. vi. figs. 19, 20; (142) Pl. xi. fig. 5.
[996] For synonymy, see Kidston (11) p. 238, Pl. xxii. figs. 3, 3a.
[997] Fiedler (57) p. 291.
[998] Stopes (14) p. 89, Pls. xxi.–xxiii.
[999] Andrews (75) p. 425, Pl. xlvi. fig. 2.
[1000] Kidston (11) p. 239, Pl. xii. fig. 1.
[1001] Dawson (71) A. Pl. xix. fig. 219; Stopes (14) p. 92.
[1002] Fiedler (57) Pl. xxviii. fig. 36.
[1003] White (08) B. p. 567, Pl. x. fig. 11.
[1004] Newberry (73) Pl. xliii. fig. 8; Lesquereux (80) A Pl. lxxxv. figs. 36, 37.
Page 773
[1005] Lesquereux (84) A Pl. cix. figs. 13, 15.
[1006] Seward (972) A p. 332; Arber (05) B. pp. 206, 207.
[1007] White (08) B. p. 559, Pl. x. figs. 5–8.
[1008] Vol. ii. p. 517.
[1009] Seward and Leslie (08) B.
[1010] Zeiller (02) B. p. 37, Pl. vii. figs. 7, 8; Arber (05) B. p. 205, fig. 44.
[1011] Lesquereux (80) A. Pl. 85, figs. 34, 35.
[1012] Feistmantel (792) p. 30; (812) p. 59, Pl. xxx. fig. 14; (82) p. 43, Pl. xv. figs. 5–12.
[1013] Arber (05) B. p. 205.
[1014] Vol. ii. p. 500.
[1015] Geinitz (71) p. 174, Pl. iii. figs. 10, 11.
[1016] Ibid. (55) A. Pl. xxi.; Zeiller (88) A. Pl. xciv. fig. 13; (06) B. p. 224; Kidston (11)
p. 240; Arber (14) p. 100.
[1017] Boulay (79) p. 34.
[1018] Zeiller (88) A. Pl. xciv. fig. 12; Kidston (11) Pl. v. figs. 5–7; Arber (14) p. 100.
[1019] Berger (48) Pl. ii. figs. 19, 20.
[1020] Renault and Zeiller (88) A. Pl. lxxii. fig. 3.
[1021] Ibid. p. 649.
[1022] Ibid. Pl. lxxii. figs. 53–55.
[1023] Williamson (77) B. p. 253, Pl. xvi. figs. 115 a, 115 b
[1024] Kidston (14) p. 165.
[1025] Bertrand, P. (13) Pl. vii.
[1026] Renault and Zeiller (88) A. p. 651, Pl. lxxii. fig. 56.
[1027] Grand’Eury (77) A. p. 185, Pls. xv., xvi.
[1028] Arber (14) pp. 93, 104, Pl. viii. figs. 51, 52.
[1029] Kidston (14) p. 157, Pl. xiv. figs. 1, 2.
[1030] See page 321.
[1031] Arber, loc. cit. p. 102.
[1032] Kidston, loc. cit. p. 158.
[1033] Heer (77) i. p. 19, Pl. v. figs. 1–11.
[1034] Nathorst (94) A. p. 48, Pl. iv. figs. 7, 8.
[1035] Young (69) Pl. iv. figs. 9, 10; (76) p. 36.
[1036] Zalessky (05).
[1037] Nathorst (14) p. 23, Pl. xv. figs. 44–51.
[1038] Lindley and Hutton (37) A. Pl. 220.
[1039] Zalessky (05).
[1040] For this information I am indebted to Dr Kidston.
[1006] Seward (972) A p. 332; Arber (05) B. pp. 206, 207.
[1007] White (08) B. p. 559, Pl. x. figs. 5–8.
[1008] Vol. ii. p. 517.
[1009] Seward and Leslie (08) B.
[1010] Zeiller (02) B. p. 37, Pl. vii. figs. 7, 8; Arber (05) B. p. 205, fig. 44.
[1011] Lesquereux (80) A. Pl. 85, figs. 34, 35.
[1012] Feistmantel (792) p. 30; (812) p. 59, Pl. xxx. fig. 14; (82) p. 43, Pl. xv. figs. 5–12.
[1013] Arber (05) B. p. 205.
[1014] Vol. ii. p. 500.
[1015] Geinitz (71) p. 174, Pl. iii. figs. 10, 11.
[1016] Ibid. (55) A. Pl. xxi.; Zeiller (88) A. Pl. xciv. fig. 13; (06) B. p. 224; Kidston (11)
p. 240; Arber (14) p. 100.
[1017] Boulay (79) p. 34.
[1018] Zeiller (88) A. Pl. xciv. fig. 12; Kidston (11) Pl. v. figs. 5–7; Arber (14) p. 100.
[1019] Berger (48) Pl. ii. figs. 19, 20.
[1020] Renault and Zeiller (88) A. Pl. lxxii. fig. 3.
[1021] Ibid. p. 649.
[1022] Ibid. Pl. lxxii. figs. 53–55.
[1023] Williamson (77) B. p. 253, Pl. xvi. figs. 115 a, 115 b
[1024] Kidston (14) p. 165.
[1025] Bertrand, P. (13) Pl. vii.
[1026] Renault and Zeiller (88) A. p. 651, Pl. lxxii. fig. 56.
[1027] Grand’Eury (77) A. p. 185, Pls. xv., xvi.
[1028] Arber (14) pp. 93, 104, Pl. viii. figs. 51, 52.
[1029] Kidston (14) p. 157, Pl. xiv. figs. 1, 2.
[1030] See page 321.
[1031] Arber, loc. cit. p. 102.
[1032] Kidston, loc. cit. p. 158.
[1033] Heer (77) i. p. 19, Pl. v. figs. 1–11.
[1034] Nathorst (94) A. p. 48, Pl. iv. figs. 7, 8.
[1035] Young (69) Pl. iv. figs. 9, 10; (76) p. 36.
[1036] Zalessky (05).
[1037] Nathorst (14) p. 23, Pl. xv. figs. 44–51.
[1038] Lindley and Hutton (37) A. Pl. 220.
[1039] Zalessky (05).
[1040] For this information I am indebted to Dr Kidston.
Page 774
[1041] Nathorst (14) p. 32, Pl. xv. fig. 58.
[1042] Zalessky (05).
[1043] Nathorst (14) p. 27, Pl. v. figs. 19–22; Pl. xv. fig.
[1044] Heer (77) i. p. 24, Pl. v. figs. 18–22.
[1045] Nathorst (14) p. 35, Pl. xv. figs. 77–82.
[1046] Grand’Eury (77) A. Pl. xvi. figs. 2–4.
[1047] Brongniart (28) A. p. 137.
[1048] Grand’Eury (77) A. p. 184, Pl. xv. fig. 3.
[1049] See page 330.
[1050] Sternberg (38) A. Pl. x. fig. 3.
[1051] Lindley and Hutton (37) A. Pl. 220.
[1052] Zalessky (05) p. 119.
[1053] Renault and Zeiller (88) A. p. 652, Pl. lxxii. figs. 63–66; Renault (96) A. p. 400;
(93) A. Pl. lxxxiv. fig. 3.
[1054] Arber (14) p. 95, Pl. vi. fig. 11.
[1055] Kidston (88) B. Pl. xxiii. fig. 4.
[1056] Nathorst (14) p. 28.
[1057] Ibid. Pl. xv. figs. 53, 54.
[1058] Williamson (77) B. p. 246, Pl. xiii. figs. 88–93.
[1059] Nathorst (14) p. 33. Pl. xv. figs. 69, 70.
[1060] See page 304.
[1061] Nathorst (14) p. 33.
[1062] Seward (95) A. p. 101.
[1063] Kidston (92) p. 8; Arber (14) Pl. vii. fig. 28.
[1064] Kidston (864) B. Pl. iii. figs. 7 a–c; Berger (48) Pl. ii. figs. 30, 31.
[1065] See postea.
[1066] Arber (14) pp. 90, 100, Pl. vii. figs. 22–27.
[1067] Carpentier (11) p. 7, Pl. xiv. fig. 3.
[1068] Geinitz (62) p. 145, Pl. xxv. figs. 7–9; Goeppert (64) A. p. 145.
[1069] Nathorst (02) p. 3.
[1070] Carruthers (70) p. 694.
[1071] Nathorst (02) p. 23.
[1072] Ibid. (092) pp. 21, 23.
[1073] Thomas and Bancroft (13) p. 196.
[1074] Buckland (27) Proc. Geol. Soc. London, Vol. i. No. 8, p. 80; (28).
[1075] Brongniart (28) A. p. 96.
[1076] Ibid. (49) A. p. 59.
[1042] Zalessky (05).
[1043] Nathorst (14) p. 27, Pl. v. figs. 19–22; Pl. xv. fig.
[1044] Heer (77) i. p. 24, Pl. v. figs. 18–22.
[1045] Nathorst (14) p. 35, Pl. xv. figs. 77–82.
[1046] Grand’Eury (77) A. Pl. xvi. figs. 2–4.
[1047] Brongniart (28) A. p. 137.
[1048] Grand’Eury (77) A. p. 184, Pl. xv. fig. 3.
[1049] See page 330.
[1050] Sternberg (38) A. Pl. x. fig. 3.
[1051] Lindley and Hutton (37) A. Pl. 220.
[1052] Zalessky (05) p. 119.
[1053] Renault and Zeiller (88) A. p. 652, Pl. lxxii. figs. 63–66; Renault (96) A. p. 400;
(93) A. Pl. lxxxiv. fig. 3.
[1054] Arber (14) p. 95, Pl. vi. fig. 11.
[1055] Kidston (88) B. Pl. xxiii. fig. 4.
[1056] Nathorst (14) p. 28.
[1057] Ibid. Pl. xv. figs. 53, 54.
[1058] Williamson (77) B. p. 246, Pl. xiii. figs. 88–93.
[1059] Nathorst (14) p. 33. Pl. xv. figs. 69, 70.
[1060] See page 304.
[1061] Nathorst (14) p. 33.
[1062] Seward (95) A. p. 101.
[1063] Kidston (92) p. 8; Arber (14) Pl. vii. fig. 28.
[1064] Kidston (864) B. Pl. iii. figs. 7 a–c; Berger (48) Pl. ii. figs. 30, 31.
[1065] See postea.
[1066] Arber (14) pp. 90, 100, Pl. vii. figs. 22–27.
[1067] Carpentier (11) p. 7, Pl. xiv. fig. 3.
[1068] Geinitz (62) p. 145, Pl. xxv. figs. 7–9; Goeppert (64) A. p. 145.
[1069] Nathorst (02) p. 3.
[1070] Carruthers (70) p. 694.
[1071] Nathorst (02) p. 23.
[1072] Ibid. (092) pp. 21, 23.
[1073] Thomas and Bancroft (13) p. 196.
[1074] Buckland (27) Proc. Geol. Soc. London, Vol. i. No. 8, p. 80; (28).
[1075] Brongniart (28) A. p. 96.
[1076] Ibid. (49) A. p. 59.
Page 775
[1077] Carruthers (70) p. 678.
[1078] Buckland (37) p. 496, Pls. lx., lxi.
[1079] Ibid. (28), Pl. lxi. fig. 1. A specimen in the Oxford Museum may be the original
of Buckland’s figure.
[1080] Carruthers (70).
[1081] Pomel (49) p. 16.
[1082] Carruthers (70) p. 690.
[1083] Saporta (75) A. pp. 256, 265, Pls. 118, 119.
[1084] Lindley and Hutton (35) A. Pl. 143.
[1085] Ward (94).
[1086] Fliche and Zeiller (04).
[1087] Saporta (75) A. p. 276, Pl. 120.
[1088] Lignier (01).
[1089] Ibid. (13) p. 93.
[1090] Solms-Laubach (91).
[1091] Seward (95) A. p. 139.
[1092] Ibid. (04) B. p. 44.
[1093] Wieland (06).
[1094] Stopes (15) p. 309.
[1095] Buckland (37) A. Vol. ii. p. 98, Pl. lxi. fig. 1.
[1096] Ibid. (28) Pl. xlix.
[1097] Seward (95) A. p. 166.
[1098] Stopes (15) p. 309.
[1099] See page 425.
[1100] Wieland (06) Pls. vi.–xiii.
[1101] Ibid. (12) p. 88, fig. 10.
[1102] Wieland (06) p. 63, fig. 33.
[1103] See Wieland (06) for additional facts and illustrations.
[1104] See page 417.
[1105] Wieland (06) p. 76; Capellini and Solms-Laubach (92) Pl. v. fig. 6.
[1106] Capellini and Solms-Laubach (92) Pl. v. fig. 2.
[1107] See Chapter xxxix.
[1108] See page 489.
[1109] Wieland (99); (06) p. 87.
[1110] Wieland in Ward (05) B. p. 200, Pl. lxiii.
[1111] Wieland (14).
[1112] The flowers are frequently described as protandrous but, as Dr Scott pointed out
to me, we have no definite evidence on this point.
[1078] Buckland (37) p. 496, Pls. lx., lxi.
[1079] Ibid. (28), Pl. lxi. fig. 1. A specimen in the Oxford Museum may be the original
of Buckland’s figure.
[1080] Carruthers (70).
[1081] Pomel (49) p. 16.
[1082] Carruthers (70) p. 690.
[1083] Saporta (75) A. pp. 256, 265, Pls. 118, 119.
[1084] Lindley and Hutton (35) A. Pl. 143.
[1085] Ward (94).
[1086] Fliche and Zeiller (04).
[1087] Saporta (75) A. p. 276, Pl. 120.
[1088] Lignier (01).
[1089] Ibid. (13) p. 93.
[1090] Solms-Laubach (91).
[1091] Seward (95) A. p. 139.
[1092] Ibid. (04) B. p. 44.
[1093] Wieland (06).
[1094] Stopes (15) p. 309.
[1095] Buckland (37) A. Vol. ii. p. 98, Pl. lxi. fig. 1.
[1096] Ibid. (28) Pl. xlix.
[1097] Seward (95) A. p. 166.
[1098] Stopes (15) p. 309.
[1099] See page 425.
[1100] Wieland (06) Pls. vi.–xiii.
[1101] Ibid. (12) p. 88, fig. 10.
[1102] Wieland (06) p. 63, fig. 33.
[1103] See Wieland (06) for additional facts and illustrations.
[1104] See page 417.
[1105] Wieland (06) p. 76; Capellini and Solms-Laubach (92) Pl. v. fig. 6.
[1106] Capellini and Solms-Laubach (92) Pl. v. fig. 2.
[1107] See Chapter xxxix.
[1108] See page 489.
[1109] Wieland (99); (06) p. 87.
[1110] Wieland in Ward (05) B. p. 200, Pl. lxiii.
[1111] Wieland (14).
[1112] The flowers are frequently described as protandrous but, as Dr Scott pointed out
to me, we have no definite evidence on this point.
Page 776
[1113] Wieland (112) p. 134; Coulter and Chamberlain (10) p. 67, fig. 55.
[1114] Wieland (06) p. 160, fig. 84.
[1115] Ibid. (14).
[1116] See also Wieland (112) p. 152, fig. 9.
[1117] Capellini and Solms-Laubach (92); Ward (96) p. 505.
[1118] Ward (96) Pl. civ.
[1119] Ward (04); Wieland (08).
[1120] Fontaine (89) B. p. 193, Pls. clxxiv.–clxxx.
[1121] Ward (942).
[1122] For an account of the stratigraphy, see Ward (943).
[1123] Ward (05) B.
[1124] Ibid. (00).
[1125] Coemans (66).
[1126] Wieland (13).
[1127] Carruthers (70).
[1128] Lignier (942).
[1129] See page 395.
[1130] Wieland (06).
[1131] Buckland (37).
[1132] See page 448.
[1133] Carruthers (70).
[1134] Ibid. p. 698; for other references, see Seward (95) A. 139.
[1135] Carruthers (70) Pls. lvii., lviii.
[1136] Capellini and Solms-Laubach (92) Pl. v. fig. 2.
[1137] See also Stopes (15) p. 47.
[1138] Chamberlain (13). See Chapter xxviii., page 6.
[1139] Solms-Laubach (91).
[1140] See page 449.
[1141] Scott (09) B, p. 571.
[1142] It is possible that, as Scott suggests, a small patch of endosperm is represented in
a seed of this species figured by him. Scott (09) B. p. 569, fig. 203, D, e.
[1143] See page 396.
[1144] The age was at first believed to be Oxfordian, but Lignier subsequently (09)
referred the rocks to a Lower Cretaceous horizon.
[1145] Morière (69).
[1146] Saporta and Marion (81) A.; (85) p. 244; Saporta (91) p. 168, Pls. 148, 149.
[1147] Lignier (942); (04); (09); (11).
[1114] Wieland (06) p. 160, fig. 84.
[1115] Ibid. (14).
[1116] See also Wieland (112) p. 152, fig. 9.
[1117] Capellini and Solms-Laubach (92); Ward (96) p. 505.
[1118] Ward (96) Pl. civ.
[1119] Ward (04); Wieland (08).
[1120] Fontaine (89) B. p. 193, Pls. clxxiv.–clxxx.
[1121] Ward (942).
[1122] For an account of the stratigraphy, see Ward (943).
[1123] Ward (05) B.
[1124] Ibid. (00).
[1125] Coemans (66).
[1126] Wieland (13).
[1127] Carruthers (70).
[1128] Lignier (942).
[1129] See page 395.
[1130] Wieland (06).
[1131] Buckland (37).
[1132] See page 448.
[1133] Carruthers (70).
[1134] Ibid. p. 698; for other references, see Seward (95) A. 139.
[1135] Carruthers (70) Pls. lvii., lviii.
[1136] Capellini and Solms-Laubach (92) Pl. v. fig. 2.
[1137] See also Stopes (15) p. 47.
[1138] Chamberlain (13). See Chapter xxviii., page 6.
[1139] Solms-Laubach (91).
[1140] See page 449.
[1141] Scott (09) B, p. 571.
[1142] It is possible that, as Scott suggests, a small patch of endosperm is represented in
a seed of this species figured by him. Scott (09) B. p. 569, fig. 203, D, e.
[1143] See page 396.
[1144] The age was at first believed to be Oxfordian, but Lignier subsequently (09)
referred the rocks to a Lower Cretaceous horizon.
[1145] Morière (69).
[1146] Saporta and Marion (81) A.; (85) p. 244; Saporta (91) p. 168, Pls. 148, 149.
[1147] Lignier (942); (04); (09); (11).
Page 777
[1148] Saporta (75) A. p. 328, Pl. 123.
[1149] Lignier (94) p. 57; (12).
[1150] Lignier (11).
[1151] Berridge (11); Thoday, M. G. (11).
[1152] Lignier (04).
[1153] Solms-Laubach (91).
[1154] Pearson (09).
[1155] Wettstein (11) p. 388.
[1156] Worsdell (002).
[1157] McBride (93).
[1158] Ward (98) p. 205.
[1159] Wieland (06) p. 185. See Wieland’s description for further details.
[1160] Ward (98) p. 208.
[1161] Wieland (06) Pls. vii.–ix., xii., xiii.
[1149] Lignier (94) p. 57; (12).
[1150] Lignier (11).
[1151] Berridge (11); Thoday, M. G. (11).
[1152] Lignier (04).
[1153] Solms-Laubach (91).
[1154] Pearson (09).
[1155] Wettstein (11) p. 388.
[1156] Worsdell (002).
[1157] McBride (93).
[1158] Ward (98) p. 205.
[1159] Wieland (06) p. 185. See Wieland’s description for further details.
[1160] Ward (98) p. 208.
[1161] Wieland (06) Pls. vii.–ix., xii., xiii.
Page 778
[1162] Ibid. Pl. xix. fig. 5.
[1163] Ibid. passim; (12).
[1164] Wieland (14).
[1165] This subject is more fully dealt with by Wieland in the Volume published since
the above was written [Wieland (16)].
[1166] Goeppert (53).
[1167] Solms-Laubach (91) A. p. 100.
[1168] Schuster (11). An excellent photograph of the stem is reproduced in this paper.
[1169] Wieland (08) p. 96.
[1170] Raciborski (922).
[1171] Seward (97) A.
[1172] Wieland (06) Pl. xix. fig. 5.
[1173] Seward (97) A. figs. 3, 4, pp. 24, 32.
[1174] Lignier (01).
[1175] Lignier (01).
[1176] Morière (69).
[1177] Saporta (75) A. Pl. l.
[1178] Ward (94) p. 87; (98) p. 216.
[1179] Wieland (06) p. 79, Pl. xiv.
[1180] Chamberlain (09).
[1181] Fliche and Zeiller (04) p. 789, Pl. xix.
[1182] Saporta (75) A. p. 262, Pl. 118.
[1183] Ward (99) B. p. 639, Pls. clvi., clvii.
[1184] Lindley and Hutton (35) A. Pl. 143. (I have not seen the actual specimen.—A. C.
S.)
[1185] Ward (002), Pls. xiv.–xxi.
[1186] Ibid. (05) B. p. 198, Pls. xlvi.–lxiii.
[1187] Wieland (06) p. 101.
[1188] Fliche (96) p. 48, Pl. v. figs. 2, 3; Pl. xiv. fig. 1.
[1189] Ibid. Pl. v. fig. 3.
[1190] Stopes (15) p. 247, Pls. xxiii.–xxv., text-figs. 72–75.
[1191] Solms-Laubach (04) p. 12, Pl. ii. figs. 5, 6.
[1192] Young and Bird (22) A. For a fuller account of the history of our knowledge of
Williamsonia, see Seward (95) A. p. 146.
[1193] Williamson (40) p. 230.
[1163] Ibid. passim; (12).
[1164] Wieland (14).
[1165] This subject is more fully dealt with by Wieland in the Volume published since
the above was written [Wieland (16)].
[1166] Goeppert (53).
[1167] Solms-Laubach (91) A. p. 100.
[1168] Schuster (11). An excellent photograph of the stem is reproduced in this paper.
[1169] Wieland (08) p. 96.
[1170] Raciborski (922).
[1171] Seward (97) A.
[1172] Wieland (06) Pl. xix. fig. 5.
[1173] Seward (97) A. figs. 3, 4, pp. 24, 32.
[1174] Lignier (01).
[1175] Lignier (01).
[1176] Morière (69).
[1177] Saporta (75) A. Pl. l.
[1178] Ward (94) p. 87; (98) p. 216.
[1179] Wieland (06) p. 79, Pl. xiv.
[1180] Chamberlain (09).
[1181] Fliche and Zeiller (04) p. 789, Pl. xix.
[1182] Saporta (75) A. p. 262, Pl. 118.
[1183] Ward (99) B. p. 639, Pls. clvi., clvii.
[1184] Lindley and Hutton (35) A. Pl. 143. (I have not seen the actual specimen.—A. C.
S.)
[1185] Ward (002), Pls. xiv.–xxi.
[1186] Ibid. (05) B. p. 198, Pls. xlvi.–lxiii.
[1187] Wieland (06) p. 101.
[1188] Fliche (96) p. 48, Pl. v. figs. 2, 3; Pl. xiv. fig. 1.
[1189] Ibid. Pl. v. fig. 3.
[1190] Stopes (15) p. 247, Pls. xxiii.–xxv., text-figs. 72–75.
[1191] Solms-Laubach (04) p. 12, Pl. ii. figs. 5, 6.
[1192] Young and Bird (22) A. For a fuller account of the history of our knowledge of
Williamsonia, see Seward (95) A. p. 146.
[1193] Williamson (40) p. 230.
Page 779
[1194] Yates (55).
[1195] Leckenby, A. (64). See also Seward (00) B. p. 190.
[1196] Williamson (70).
[1197] Carruthers (70).
[1198] Saporta (91).
[1199] Seward (974).
[1200] Wieland (11).
[1201] Wieland (13).
[1202] Nathorst (13).
[1203] See page 480.
[1204] Williamson (70) Pl. liii. fig. 5; Seward (974).
[1205] Saporta (75) A. Pl. xi. fig. 1.
[1206] Ibid. Pl. xv.
[1207] Wieland (11) p. 448, fig. 6.
[1208] Seward (95) A. p. 146.
[1209] Nathorst (09) (11).
[1210] Lignier (07).
[1211] Saporta (91) Pl. 248.
[1212] Nathorst (09) Pl. iii.
[1213] Krasser (12).
[1214] Lignier (03).
[1215] Wieland (06) p. 152.
[1216] Lignier (07); Wieland (11) p. 462.
[1217] Nathorst (11) Pl. ii.
[1218] Thomas (152).
[1219] Thomas (15).
[1220] Nathorst (09) p. 6, Pls. i., ii.; (11) p. 5, Pls. i., iii.; (12).
[1221] Thomas (132) p. 230, Pl. xxiv. figs. 1–3.
[1222] Capellini and Solms-Laubach (92) Pl. v. fig. 7.
[1223] Nathorst (09) Pl. i. figs. 1–3.
[1224] Ibid. (80) p. 39. See also Saporta (91) p. 161, Pl. 248.
[1225] Seward (00) B. p. 201, fig. 35.
[1226] Nathorst (09) p. 14, Pls. ii., iii.
[1227] Carruthers (70) p. 694.
[1228] Nathorst (11) p. 19.
[1229] Nathorst (11) p. 9, Pls. ii., iii. See also Nathorst (09) p. 8, Pls. i., ii.
[1230] Leckenby (64) A.
[1195] Leckenby, A. (64). See also Seward (00) B. p. 190.
[1196] Williamson (70).
[1197] Carruthers (70).
[1198] Saporta (91).
[1199] Seward (974).
[1200] Wieland (11).
[1201] Wieland (13).
[1202] Nathorst (13).
[1203] See page 480.
[1204] Williamson (70) Pl. liii. fig. 5; Seward (974).
[1205] Saporta (75) A. Pl. xi. fig. 1.
[1206] Ibid. Pl. xv.
[1207] Wieland (11) p. 448, fig. 6.
[1208] Seward (95) A. p. 146.
[1209] Nathorst (09) (11).
[1210] Lignier (07).
[1211] Saporta (91) Pl. 248.
[1212] Nathorst (09) Pl. iii.
[1213] Krasser (12).
[1214] Lignier (03).
[1215] Wieland (06) p. 152.
[1216] Lignier (07); Wieland (11) p. 462.
[1217] Nathorst (11) Pl. ii.
[1218] Thomas (152).
[1219] Thomas (15).
[1220] Nathorst (09) p. 6, Pls. i., ii.; (11) p. 5, Pls. i., iii.; (12).
[1221] Thomas (132) p. 230, Pl. xxiv. figs. 1–3.
[1222] Capellini and Solms-Laubach (92) Pl. v. fig. 7.
[1223] Nathorst (09) Pl. i. figs. 1–3.
[1224] Ibid. (80) p. 39. See also Saporta (91) p. 161, Pl. 248.
[1225] Seward (00) B. p. 201, fig. 35.
[1226] Nathorst (09) p. 14, Pls. ii., iii.
[1227] Carruthers (70) p. 694.
[1228] Nathorst (11) p. 19.
[1229] Nathorst (11) p. 9, Pls. ii., iii. See also Nathorst (09) p. 8, Pls. i., ii.
[1230] Leckenby (64) A.
Page 780
[1231] Nathorst (12) p. 7.
[1232] Williamson (70) Pl. lii. fig. 1; Pl. liii. fig. 2.
[1233] Seward (00) B. p. 201, Pl. ii. fig. 7.
[1234] Nathorst (11) p. 19, Pl. v. figs. 1–8; Pl. vi. figs. 1–3. The name Palaeozamia
pecten was applied by Leckenby [Leckenby (64) A. p. 77, Pl. ix. fig. 47] both to the
fronds and an associated flower which is now recognised as a whorl of
microsporophylls. I formerly employed the name Williamsonia pecten for fronds and
flowers, but in view of Nathorst’s work it is advisable to follow his example and to use
separate names for male and female flowers when there is no proof that they belong to
one type; similarly the fronds may conveniently be spoken of as Ptilophyllum pecten.
[1235] Nathorst (11) p. 17, Pl. iv.
[1236] Nathorst (09) Pl. vii. fig. 1.
[1237] See page 444.
[1238] Oldham and Morris (63) B. Pl. xxxii. fig. 2.
[1239] Feistmantel (772) p. 76; (775) Pl. ii. fig. 5.
[1240] Ibid. (772) Pl. xliv. fig. 2.
[1241] Feistmantel (772) Pl. xliv. figs. 3, 4.
[1242] Williamson (70) Pl. lii. fig. 1.
[1243] Wieland (11) p. 460, fig. 16 B.
[1244] Nathorst (09) p. 6.
[1245] Feistmantel (772) Pl. xli. fig. 4; (77) Pl. i. fig. 6; Pl. ii. fig. 4.
[1246] Ibid. (762) p. 52, Pl. xii. figs. 5–7; (775) Pl. i. figs. 4, 5; Pl. ii. fig. 6.
[1247] Feistmantel (773) p. 181, Pl. vii. figs. 1–4; (771) Pl. ii. figs. 1–3.
[1248] My thanks are due to Mr Wieland for a photograph of this species that is
mentioned but not figured in his paper on the Mexican Flora, Wieland (13).
[1249] Bancroft (13) p. 76, Pl. vii. figs. 1–5.
[1250] Seward (95) A. p. 157, Pls. x., xi.
[1251] Buckland (37) Vol. i. p. 505, Vol. ii. p. 101, Pl. lxiii. figs. 2–10.
[1252] Unger (50) A. p. 327.
[1253] Brongniart (49) A. p. 88.
[1254] Saporta (91) p. 127, Pls. 238, 239.
[1255] For other references, see Seward (04) B. p. 105.
[1256] Miller (57) B. p. 480. For a detailed description and illustrations, see Seward
(122).
[1257] Thomas and Bancroft (13) p. 184.
[1258] Bancroft (13).
[1259] Lignier (01).
[1260] Nathorst (11) p. 24, Pl. v. figs. 9–11.
[1232] Williamson (70) Pl. lii. fig. 1; Pl. liii. fig. 2.
[1233] Seward (00) B. p. 201, Pl. ii. fig. 7.
[1234] Nathorst (11) p. 19, Pl. v. figs. 1–8; Pl. vi. figs. 1–3. The name Palaeozamia
pecten was applied by Leckenby [Leckenby (64) A. p. 77, Pl. ix. fig. 47] both to the
fronds and an associated flower which is now recognised as a whorl of
microsporophylls. I formerly employed the name Williamsonia pecten for fronds and
flowers, but in view of Nathorst’s work it is advisable to follow his example and to use
separate names for male and female flowers when there is no proof that they belong to
one type; similarly the fronds may conveniently be spoken of as Ptilophyllum pecten.
[1235] Nathorst (11) p. 17, Pl. iv.
[1236] Nathorst (09) Pl. vii. fig. 1.
[1237] See page 444.
[1238] Oldham and Morris (63) B. Pl. xxxii. fig. 2.
[1239] Feistmantel (772) p. 76; (775) Pl. ii. fig. 5.
[1240] Ibid. (772) Pl. xliv. fig. 2.
[1241] Feistmantel (772) Pl. xliv. figs. 3, 4.
[1242] Williamson (70) Pl. lii. fig. 1.
[1243] Wieland (11) p. 460, fig. 16 B.
[1244] Nathorst (09) p. 6.
[1245] Feistmantel (772) Pl. xli. fig. 4; (77) Pl. i. fig. 6; Pl. ii. fig. 4.
[1246] Ibid. (762) p. 52, Pl. xii. figs. 5–7; (775) Pl. i. figs. 4, 5; Pl. ii. fig. 6.
[1247] Feistmantel (773) p. 181, Pl. vii. figs. 1–4; (771) Pl. ii. figs. 1–3.
[1248] My thanks are due to Mr Wieland for a photograph of this species that is
mentioned but not figured in his paper on the Mexican Flora, Wieland (13).
[1249] Bancroft (13) p. 76, Pl. vii. figs. 1–5.
[1250] Seward (95) A. p. 157, Pls. x., xi.
[1251] Buckland (37) Vol. i. p. 505, Vol. ii. p. 101, Pl. lxiii. figs. 2–10.
[1252] Unger (50) A. p. 327.
[1253] Brongniart (49) A. p. 88.
[1254] Saporta (91) p. 127, Pls. 238, 239.
[1255] For other references, see Seward (04) B. p. 105.
[1256] Miller (57) B. p. 480. For a detailed description and illustrations, see Seward
(122).
[1257] Thomas and Bancroft (13) p. 184.
[1258] Bancroft (13).
[1259] Lignier (01).
[1260] Nathorst (11) p. 24, Pl. v. figs. 9–11.
Page 781
[1261] Wieland (11) p. 462.
[1262] Nathorst (09) p. 10; (11) p. 14.
[1263] Nathorst (09) p. 10.
[1264] Williamson (70) Pl. lii.: see also Seward (00) B, Pl. viii. fig. 1.
[1265] Nathorst (09) p. 12, fig. 2.
[1266] Lignier (032) p. 34.
[1267] In addition to the papers already quoted, reference should also be made to
Thomas (152).
[1268] Wieland (09) p. 430 (the species is here referred to as the ‘El consuelo
Williamsonia’); (11) p. 461, fig. 17 C.
[1269] Zigno (85) Pl. xlii.
[1270] Seward (12) p. 26, Pl. iii. fig. 44; Pl. vii. fig. 86.
[1271] Zigno (85) p. 173, Pl. xlii. figs. 9–11.
[1272] Seward (112) p. 691, Pl. v. fig. 99.
[1273] Fontaine in Ward (05) B. p. 118, Pl. xxix. fig. 6.
[1274] Nathorst (80) p. 41, Pl. viii. fig. 7.
[1275] Saporta (94) B. p. 105, Pl. xix. fig. 9.
[1276] Newberry and Hollick (95) p. 125, Pl. xxxv. figs. 1–9.
[1277] Hollick (06) p. 107, Pl. v. figs. 27–32; (12) p. 156, Pl. clxiii. fig. 4.
[1278] Newberry and Hollick (95) p. 127, Pl. xxxvi. figs. 1–8.
[1279] Hollick (06) p. 107, Pl. v. figs. 25, 26.
[1280] Ward (99) B. p. 668, Pl. clxii. fig. 20.
[1281] Lesquereux (91) p. 87, Pl. ii. fig. 9.
[1282] Fontaine (89) B. p. 273, Pls. 133, 165.
[1283] Fontaine in Ward (05) B. p. 485, Pl. cvii. fig. 4.
[1284] Ward (05) B. p. 554, Pl. cxv. fig. 11.
[1285] Berry (11) p. 405, Pl. lxvii. figs. 1–4.
[1286] Heer (82) B, p. 59, Pls. xii., xiii.
[1287] Dawson (85) p. 12, Pl. iv. fig. 1.
[1288] Nathorst (80) p. 50.
[1289] Ibid. (88); (02) p. 9, Pls. i.–iii.
[1290] Ibid. (09) p. 22, Pls. v., vi.
[1291] Ibid. p. 33.
[1292] South and Compton (08) p. 225, fig. 36.
[1293] For figures of the stem and flowers, see Nathorst (02); (09).
[1294] Thomas (152).
[1262] Nathorst (09) p. 10; (11) p. 14.
[1263] Nathorst (09) p. 10.
[1264] Williamson (70) Pl. lii.: see also Seward (00) B, Pl. viii. fig. 1.
[1265] Nathorst (09) p. 12, fig. 2.
[1266] Lignier (032) p. 34.
[1267] In addition to the papers already quoted, reference should also be made to
Thomas (152).
[1268] Wieland (09) p. 430 (the species is here referred to as the ‘El consuelo
Williamsonia’); (11) p. 461, fig. 17 C.
[1269] Zigno (85) Pl. xlii.
[1270] Seward (12) p. 26, Pl. iii. fig. 44; Pl. vii. fig. 86.
[1271] Zigno (85) p. 173, Pl. xlii. figs. 9–11.
[1272] Seward (112) p. 691, Pl. v. fig. 99.
[1273] Fontaine in Ward (05) B. p. 118, Pl. xxix. fig. 6.
[1274] Nathorst (80) p. 41, Pl. viii. fig. 7.
[1275] Saporta (94) B. p. 105, Pl. xix. fig. 9.
[1276] Newberry and Hollick (95) p. 125, Pl. xxxv. figs. 1–9.
[1277] Hollick (06) p. 107, Pl. v. figs. 27–32; (12) p. 156, Pl. clxiii. fig. 4.
[1278] Newberry and Hollick (95) p. 127, Pl. xxxvi. figs. 1–8.
[1279] Hollick (06) p. 107, Pl. v. figs. 25, 26.
[1280] Ward (99) B. p. 668, Pl. clxii. fig. 20.
[1281] Lesquereux (91) p. 87, Pl. ii. fig. 9.
[1282] Fontaine (89) B. p. 273, Pls. 133, 165.
[1283] Fontaine in Ward (05) B. p. 485, Pl. cvii. fig. 4.
[1284] Ward (05) B. p. 554, Pl. cxv. fig. 11.
[1285] Berry (11) p. 405, Pl. lxvii. figs. 1–4.
[1286] Heer (82) B, p. 59, Pls. xii., xiii.
[1287] Dawson (85) p. 12, Pl. iv. fig. 1.
[1288] Nathorst (80) p. 50.
[1289] Ibid. (88); (02) p. 9, Pls. i.–iii.
[1290] Ibid. (09) p. 22, Pls. v., vi.
[1291] Ibid. p. 33.
[1292] South and Compton (08) p. 225, fig. 36.
[1293] For figures of the stem and flowers, see Nathorst (02); (09).
[1294] Thomas (152).
Page 782
[1295] Nathorst retains the name Anomozamites minor for the leaves, restricting
Wielandiella to the plant as a whole including strobili and stems which usually occur in
organic union [Nathorst (13)].
[1296] Nathorst (09) p. 25, Pl. vii. figs. 14–22.
[1297] Thomas (132), p. 239.
[1298] Nathorst (02) p. 16.
[1299] Thiselton-Dyer (72).
[1300] Wieland (11) p. 458.
[1301] Thomas (152).
[1302] See page 449.
[1303] See page 463.
[1304] Seward (00) B. xvi. fig. 1; Thomas, H. H. (152) Pl. xiv. fig. 26.
[1305] Nathorst (02) p. 7, Pl. 1.
[1306] Ibid. (09) p. 27, Pl. viii.; (122) Pls. i., ii.; (12).
[1307] See the photographs reproduced in Nathorst’s latest and most complete account
(122).
[1308] Bower (97) B.
[1309] Braun (49). (I have not seen this paper.)
[1310] Saporta (91) p. 191, Pls. 253–255.
[1311] See page 428.
[1312] Nathorst (09) p. 28.
[1313] Ibid. (112); (122).
[1314] Schuster (112).
[1315] Schimper (72) A. p. 200.
[1316] Zeitsch. f. Bot. 1912, p. 456.
[1317] Saporta (91) pp. 204, 206, Pls. 254, 255.
[1318] Mantell (27).
[1319] See page 463.
[1320] Carruthers (70).
[1321] Saporta (75) A. pp. 256 et seq.
[1322] Saporta (75) A. p. 293, Pls. 123, 124.
[1323] See p. 415.
[1324] Saporta (75) A. p. 256.
[1325] Presl in Sternberg (25) A. p. xxxiii.
[1326] Mantell (27).
[1327] Stokes and Webb (24).
[1328] Brongniart (22) A. p. 209; (28) A. p. 128.
Wielandiella to the plant as a whole including strobili and stems which usually occur in
organic union [Nathorst (13)].
[1296] Nathorst (09) p. 25, Pl. vii. figs. 14–22.
[1297] Thomas (132), p. 239.
[1298] Nathorst (02) p. 16.
[1299] Thiselton-Dyer (72).
[1300] Wieland (11) p. 458.
[1301] Thomas (152).
[1302] See page 449.
[1303] See page 463.
[1304] Seward (00) B. xvi. fig. 1; Thomas, H. H. (152) Pl. xiv. fig. 26.
[1305] Nathorst (02) p. 7, Pl. 1.
[1306] Ibid. (09) p. 27, Pl. viii.; (122) Pls. i., ii.; (12).
[1307] See the photographs reproduced in Nathorst’s latest and most complete account
(122).
[1308] Bower (97) B.
[1309] Braun (49). (I have not seen this paper.)
[1310] Saporta (91) p. 191, Pls. 253–255.
[1311] See page 428.
[1312] Nathorst (09) p. 28.
[1313] Ibid. (112); (122).
[1314] Schuster (112).
[1315] Schimper (72) A. p. 200.
[1316] Zeitsch. f. Bot. 1912, p. 456.
[1317] Saporta (91) pp. 204, 206, Pls. 254, 255.
[1318] Mantell (27).
[1319] See page 463.
[1320] Carruthers (70).
[1321] Saporta (75) A. pp. 256 et seq.
[1322] Saporta (75) A. p. 293, Pls. 123, 124.
[1323] See p. 415.
[1324] Saporta (75) A. p. 256.
[1325] Presl in Sternberg (25) A. p. xxxiii.
[1326] Mantell (27).
[1327] Stokes and Webb (24).
[1328] Brongniart (22) A. p. 209; (28) A. p. 128.
Page 783
[1329] Carruthers (70) p. 682.
[1330] Carruthers (67); (70) p. 688.
[1331] Stopes (15) p. 309. See postea, p. 486.
[1332] Nathorst (86) Pl. xviii. fig. 5.
[1333] Stokes and Webb (24) Pls. xiv.–xvii.
[1334] Carruthers (70) p. 686, Pl. liv. See also Seward (95) A. p. 123.
[1335] Seward (95) A. p. 132, Pl. ix. fig. 6; (13) p. 101.
[1336] Ibid. Pl. i. fig. 2.
[1337] Carruthers (70) p. 689, Pl. lv. fig. 2.
[1338] Seward (04) B. p. 45.
[1339] Carruthers (70) p. 687, Pl. lv. fig. 1.
[1340] Carruthers, p. 689, Pl. lv. figs. 7–9.
[1341] Carruthers (67); (70) p. 688, Pl. lv. figs. 3–6. See also Seward (95) A. p. 166.
[1342] Stopes (15) p. 299, text-figs. 93–97.
[1343] Stopes (15) p. 309, text-figs. 98–100.
[1344] Sternberg (25) A. Pl. 30.
[1345] Brongniart (28) A. p. 128.
[1346] Carruthers (70) p. 686.
[1347] Ibid. (70) p. 690, Pl. lvi.
[1348] Saporta (75) A. p. 308, Pls. 125, 126.
[1349] Ibid. p. 322, Pl. 127, figs. 1–3.
[1350] Oldham and Morris (63) B. Pl. xxxiv.
[1351] Feistmantel (772) p. 78.
[1352] Wieland (11) p. 440.
[1353] Seward (00) B. p. 194.
[1354] Bancroft (13).
[1355] For illustrations and further details see Bancroft (13).
[1356] Saporta (75) A. p. 331, Pl. 119, fig. 3.
[1357] Lignier (95) p. 11, fig. 1.
[1358] Ibid. p. 15, fig. 2.
[1359] Stokes and Webb (24) Pl. xlv.; Mantell (27), etc. See Seward (95) A. pp. 126,
130, etc., for other references.
[1360] Ward (99) B. p. 693, Pl. 169, fig. 19.
[1361] Feistmantel (762) Pl. x. fig. 2.
[1362] Hollick and Jeffrey (09) B. p. 17.
[1363] Stopes (15) p. 314, Pls. xxxi., xxxii., text-figs. 101–111.
[1364] Saporta (75) A. p. 200, Pl. 114, figs. 4–6.
[1330] Carruthers (67); (70) p. 688.
[1331] Stopes (15) p. 309. See postea, p. 486.
[1332] Nathorst (86) Pl. xviii. fig. 5.
[1333] Stokes and Webb (24) Pls. xiv.–xvii.
[1334] Carruthers (70) p. 686, Pl. liv. See also Seward (95) A. p. 123.
[1335] Seward (95) A. p. 132, Pl. ix. fig. 6; (13) p. 101.
[1336] Ibid. Pl. i. fig. 2.
[1337] Carruthers (70) p. 689, Pl. lv. fig. 2.
[1338] Seward (04) B. p. 45.
[1339] Carruthers (70) p. 687, Pl. lv. fig. 1.
[1340] Carruthers, p. 689, Pl. lv. figs. 7–9.
[1341] Carruthers (67); (70) p. 688, Pl. lv. figs. 3–6. See also Seward (95) A. p. 166.
[1342] Stopes (15) p. 299, text-figs. 93–97.
[1343] Stopes (15) p. 309, text-figs. 98–100.
[1344] Sternberg (25) A. Pl. 30.
[1345] Brongniart (28) A. p. 128.
[1346] Carruthers (70) p. 686.
[1347] Ibid. (70) p. 690, Pl. lvi.
[1348] Saporta (75) A. p. 308, Pls. 125, 126.
[1349] Ibid. p. 322, Pl. 127, figs. 1–3.
[1350] Oldham and Morris (63) B. Pl. xxxiv.
[1351] Feistmantel (772) p. 78.
[1352] Wieland (11) p. 440.
[1353] Seward (00) B. p. 194.
[1354] Bancroft (13).
[1355] For illustrations and further details see Bancroft (13).
[1356] Saporta (75) A. p. 331, Pl. 119, fig. 3.
[1357] Lignier (95) p. 11, fig. 1.
[1358] Ibid. p. 15, fig. 2.
[1359] Stokes and Webb (24) Pl. xlv.; Mantell (27), etc. See Seward (95) A. pp. 126,
130, etc., for other references.
[1360] Ward (99) B. p. 693, Pl. 169, fig. 19.
[1361] Feistmantel (762) Pl. x. fig. 2.
[1362] Hollick and Jeffrey (09) B. p. 17.
[1363] Stopes (15) p. 314, Pls. xxxi., xxxii., text-figs. 101–111.
[1364] Saporta (75) A. p. 200, Pl. 114, figs. 4–6.
Page 784
[1365] Seward (95) A. p. 96.
[1366] Feistmantel (762) Pl. vii. fig. 5.
[1367] Seward (95) A. p. 98, Pl. v. figs. 2, 6; (03) B. p. 31.
[1368] Ibid. (13) p. 101, Pl. xii. figs. 3, 4; Pl. xiv. fig. 6.
[1369] Saporta (75) A. Pl. 127.
[1370] Carruthers (70) Pl. lvi.
[1371] I am indebted to Mr Edwards of the Geological Department of the British
Museum for making a preparation of the cuticle.
[1372] Tate (67) Pl. vi. fig. 4; Seward (03) B. p. 29, Pl. iv. figs. 3–6.
[1373] For further reference to this generic name, as applied to Palaeozoic seeds, see
page 364.
[1374] Nathorst (14) p. 33.
[1375] Ward (00) B. p. 363.
[1376] Pomel (49) p. 16.
[1377] Lindley and Hutton (36) A. Pl. 189. See also Seward (04) B. p. 124.
[1378] Lindley and Hutton (36) A. Pl. 189, figs. 3, 5.
[1379] Seward (95) A. p. 105, fig. 7.
[1380] Saporta (75) A. p. 242, Pl. 117, fig. 9.
[1381] Fontaine (89) B. p. 270, Pls. 135, 136.
[1382] Compter, G. (03).
[1383] Schimper (72) A. p. 207, Pl. lxxii. figs. 18–23.
[1384] Pomel (49) p. 13.
[1385] Schenk (67) A. p. 150, Pl. xxxiii. fig. 10.
[1386] See page 141.
[1387] Zigno (85) p. 156, Pl. xlii.
[1388] Saporta (91) p. 466, Pl. 298.
[1389] Seward (112) p. 699, Pl. vii. fig. 18.
[1390] Saporta (75) A. Pl. 116; (91) Pl. 298.
[1391] Saporta and Marion (85) p. 111.
[1392] Nathorst (86) p. 80, Pl. xvii. fig. 7.
[1393] Ibid. (02) p. 6, Pl. i. fig. 11.
[1394] Carruthers (69).
[1395] Lindley and Hutton (35) A. Pl. 159.
[1396] Seward and Gowan (00) B. p. 143; Seward (00) B. p. 275, Pl. ix. fig. 11.
[1397] Nathorst (02) p. 21, Pl. i. figs. 14, 15.
[1398] Nathorst (02) p. 20, Pl. i. figs. 22, 23.
[1399] Ibid. (092) p. 23.
[1366] Feistmantel (762) Pl. vii. fig. 5.
[1367] Seward (95) A. p. 98, Pl. v. figs. 2, 6; (03) B. p. 31.
[1368] Ibid. (13) p. 101, Pl. xii. figs. 3, 4; Pl. xiv. fig. 6.
[1369] Saporta (75) A. Pl. 127.
[1370] Carruthers (70) Pl. lvi.
[1371] I am indebted to Mr Edwards of the Geological Department of the British
Museum for making a preparation of the cuticle.
[1372] Tate (67) Pl. vi. fig. 4; Seward (03) B. p. 29, Pl. iv. figs. 3–6.
[1373] For further reference to this generic name, as applied to Palaeozoic seeds, see
page 364.
[1374] Nathorst (14) p. 33.
[1375] Ward (00) B. p. 363.
[1376] Pomel (49) p. 16.
[1377] Lindley and Hutton (36) A. Pl. 189. See also Seward (04) B. p. 124.
[1378] Lindley and Hutton (36) A. Pl. 189, figs. 3, 5.
[1379] Seward (95) A. p. 105, fig. 7.
[1380] Saporta (75) A. p. 242, Pl. 117, fig. 9.
[1381] Fontaine (89) B. p. 270, Pls. 135, 136.
[1382] Compter, G. (03).
[1383] Schimper (72) A. p. 207, Pl. lxxii. figs. 18–23.
[1384] Pomel (49) p. 13.
[1385] Schenk (67) A. p. 150, Pl. xxxiii. fig. 10.
[1386] See page 141.
[1387] Zigno (85) p. 156, Pl. xlii.
[1388] Saporta (91) p. 466, Pl. 298.
[1389] Seward (112) p. 699, Pl. vii. fig. 18.
[1390] Saporta (75) A. Pl. 116; (91) Pl. 298.
[1391] Saporta and Marion (85) p. 111.
[1392] Nathorst (86) p. 80, Pl. xvii. fig. 7.
[1393] Ibid. (02) p. 6, Pl. i. fig. 11.
[1394] Carruthers (69).
[1395] Lindley and Hutton (35) A. Pl. 159.
[1396] Seward and Gowan (00) B. p. 143; Seward (00) B. p. 275, Pl. ix. fig. 11.
[1397] Nathorst (02) p. 21, Pl. i. figs. 14, 15.
[1398] Nathorst (02) p. 20, Pl. i. figs. 22, 23.
[1399] Ibid. (092) p. 23.
Page 785
[1400] See Vol. iv.
[1401] Endlicher (40) p. 72. See also Schimper (72) A. p. 201.
[1402] Lindley and Hutton (35) A. Pl. 125.
[1403] Carruthers (673) p. 104.
[1404] Heer (77) ii. p. 47, Pl. xiii. fig. 10.
[1405] Fliche (96) p. 27, Pl. i. fig. 3.
[1406] Seward (95) A. pp. 113 et seq.; (96) A. p. 215; (04) B. pp. 138, 150.
[1407] Solms-Laubach (91) A. p. 92.
[1408] Lindley and Hutton (35) A. Pl. 136.
[1409] Corda in Reuss (46) B. Pl. xlvi.
[1410] Velenovský (85) B. Pl. 6, Pls. iii.–v.
[1411] Carruthers (70) Pl. liv. fig. 6.
[1412] Saporta and Marion (85) p. 116, fig. 61, B.
[1413] Schimper (72) A. p. 199.
[1414] See Vol. iv.
[1415] Saporta (75) A. p. 209, Pl. 115, figs. 1, 2.
[1416] Heer (77) ii. p. 47, Pl. iv. figs. 14, 15.
[1417] Nathorst (782) B. p. 49, Pl. ii. figs. 15, 16.
[1418] Corda in Reuss (46) B. p. 86, Pl. xlix. figs. 10, 11.
[1419] Carruthers (672) p. 6.
[1420] Velenovský (85) B. p. 8, Pl. iii. figs. 1–3, 6, 11.
[1421] Vol. ii. p. 88.
[1422] Seward (95) A. p. 110, Pl. ix. figs. 1–4.
[1423] I am indebted to Mr W. N. Edwards of the British Museum for the cuticular
preparations.
[1424] Newberry (88) p. 346, Pl. viii. fig. 5.
[1425] Lesquereux (91) p. 29, Pl. i. fig. 12.
[1426] Fontaine (89) B. p. 174, Pl. lxx. fig. 4; Pl. lxxi. figs. 3, 4, etc.
[1427] Saporta (74); Saporta and Marion (85) p. 116, fig. 61 C.
[1428] Ettingshausen (882) p. 272, Pl. iii. fig. 10.
[1429] Thomas, H. H. (152).
[1430] Gutbier (49) Pl. viii. fig. 7. For a fuller account of Palaeozoic records, see Seward
(95) A. p. 9.
[1431] Eichwald (55) Vol. i. Pl. xv. figs. 5, 6; Zeiller (96) A. p. 474.
[1432] Sandberger (64) Pl. ii. figs. 1–4.
[1433] Saporta and Marion (85) p. 109; Zeiller (06) B. p. 194.
[1434] Goeppert (44) Pl. i. fig. 6.
[1401] Endlicher (40) p. 72. See also Schimper (72) A. p. 201.
[1402] Lindley and Hutton (35) A. Pl. 125.
[1403] Carruthers (673) p. 104.
[1404] Heer (77) ii. p. 47, Pl. xiii. fig. 10.
[1405] Fliche (96) p. 27, Pl. i. fig. 3.
[1406] Seward (95) A. pp. 113 et seq.; (96) A. p. 215; (04) B. pp. 138, 150.
[1407] Solms-Laubach (91) A. p. 92.
[1408] Lindley and Hutton (35) A. Pl. 136.
[1409] Corda in Reuss (46) B. Pl. xlvi.
[1410] Velenovský (85) B. Pl. 6, Pls. iii.–v.
[1411] Carruthers (70) Pl. liv. fig. 6.
[1412] Saporta and Marion (85) p. 116, fig. 61, B.
[1413] Schimper (72) A. p. 199.
[1414] See Vol. iv.
[1415] Saporta (75) A. p. 209, Pl. 115, figs. 1, 2.
[1416] Heer (77) ii. p. 47, Pl. iv. figs. 14, 15.
[1417] Nathorst (782) B. p. 49, Pl. ii. figs. 15, 16.
[1418] Corda in Reuss (46) B. p. 86, Pl. xlix. figs. 10, 11.
[1419] Carruthers (672) p. 6.
[1420] Velenovský (85) B. p. 8, Pl. iii. figs. 1–3, 6, 11.
[1421] Vol. ii. p. 88.
[1422] Seward (95) A. p. 110, Pl. ix. figs. 1–4.
[1423] I am indebted to Mr W. N. Edwards of the British Museum for the cuticular
preparations.
[1424] Newberry (88) p. 346, Pl. viii. fig. 5.
[1425] Lesquereux (91) p. 29, Pl. i. fig. 12.
[1426] Fontaine (89) B. p. 174, Pl. lxx. fig. 4; Pl. lxxi. figs. 3, 4, etc.
[1427] Saporta (74); Saporta and Marion (85) p. 116, fig. 61 C.
[1428] Ettingshausen (882) p. 272, Pl. iii. fig. 10.
[1429] Thomas, H. H. (152).
[1430] Gutbier (49) Pl. viii. fig. 7. For a fuller account of Palaeozoic records, see Seward
(95) A. p. 9.
[1431] Eichwald (55) Vol. i. Pl. xv. figs. 5, 6; Zeiller (96) A. p. 474.
[1432] Sandberger (64) Pl. ii. figs. 1–4.
[1433] Saporta and Marion (85) p. 109; Zeiller (06) B. p. 194.
[1434] Goeppert (44) Pl. i. fig. 6.
Page 786
[1435] Ibid. (66) Pl. ii.
[1436] Saporta and Marion (78) Pl. i. figs. 4, 5.
[1437] Ibid. (85) fig. 61, A, p. 116.
[1438] Krasser (03) p. 852.
[1439] Ettingshausen (86) Pl. viii. figs. 19–21; (88) Pl. viii. figs. 19–21.
[1440] Nathorst (123) p. 36.
[1441] Thomas and Bancroft (13).
[1442] The genus Ptilozamites described briefly in Volume ii. has recently been fully
investigated by Antevs[1443] who had access to the rich material in the Stockholm
Museum from the Rhaetic beds of Scania. He thinks that the genus is intermediate
between Anomozamites and Ctenopteris; its systematic position has not been definitely
established but, as Antevs says, there seems to be no reason why it should not be a
member of the Cycadophyta. In some species, e.g. Ptilozamites fallax Nath. and P.
Nilssoni Nath., the rachis is forked, while in P. Heeri Nath. with linear fronds reaching a
length of 53 cm. the rachis is undivided.
[1443] Antevs (142).
[1444] See page 502.
[1445] Nathorst (08) Pl. i. figs. 3–5; Thomas and Bancroft (13) p. 194, Pl. xx. fig. 12.
[1446] Fontaine (89) B. p. 160, Pls. lxi.–lxvi.; Berry (11) p. 354.
[1447] Morris (40) Pl. xxi. figs. 1–4.
[1448] Lindley and Hutton (34) A. Pl. cii.
[1449] Morris (41) p. 116.
[1450] Ibid. (54) p. 15.
[1451] Oldham and Morris (63) B. p. 27.
[1452] Feistmantel (762).
[1453] Ibid. (762) p. 42.
[1454] Ibid. (772) Pl. xl. figs. 1, 2.
[1455] Ibid. (772) p. 94, Pls. v. vi.
[1456] Ibid. (79).
[1457] Ibid. (774).
[1458] Seward (00) B. p. 193.
[1459] Ibid. (03) p. 227.
[1460] Halle (132).
[1461] Halle (132).
[1462] Thomas and Bancroft (13) p. 184.
[1463] Phillips (29) A. Pl. vii. fig. 22; Pl. x. fig. 4.
[1464] Heer (75) ii.
[1465] Halle (132).
[1436] Saporta and Marion (78) Pl. i. figs. 4, 5.
[1437] Ibid. (85) fig. 61, A, p. 116.
[1438] Krasser (03) p. 852.
[1439] Ettingshausen (86) Pl. viii. figs. 19–21; (88) Pl. viii. figs. 19–21.
[1440] Nathorst (123) p. 36.
[1441] Thomas and Bancroft (13).
[1442] The genus Ptilozamites described briefly in Volume ii. has recently been fully
investigated by Antevs[1443] who had access to the rich material in the Stockholm
Museum from the Rhaetic beds of Scania. He thinks that the genus is intermediate
between Anomozamites and Ctenopteris; its systematic position has not been definitely
established but, as Antevs says, there seems to be no reason why it should not be a
member of the Cycadophyta. In some species, e.g. Ptilozamites fallax Nath. and P.
Nilssoni Nath., the rachis is forked, while in P. Heeri Nath. with linear fronds reaching a
length of 53 cm. the rachis is undivided.
[1443] Antevs (142).
[1444] See page 502.
[1445] Nathorst (08) Pl. i. figs. 3–5; Thomas and Bancroft (13) p. 194, Pl. xx. fig. 12.
[1446] Fontaine (89) B. p. 160, Pls. lxi.–lxvi.; Berry (11) p. 354.
[1447] Morris (40) Pl. xxi. figs. 1–4.
[1448] Lindley and Hutton (34) A. Pl. cii.
[1449] Morris (41) p. 116.
[1450] Ibid. (54) p. 15.
[1451] Oldham and Morris (63) B. p. 27.
[1452] Feistmantel (762).
[1453] Ibid. (762) p. 42.
[1454] Ibid. (772) Pl. xl. figs. 1, 2.
[1455] Ibid. (772) p. 94, Pls. v. vi.
[1456] Ibid. (79).
[1457] Ibid. (774).
[1458] Seward (00) B. p. 193.
[1459] Ibid. (03) p. 227.
[1460] Halle (132).
[1461] Halle (132).
[1462] Thomas and Bancroft (13) p. 184.
[1463] Phillips (29) A. Pl. vii. fig. 22; Pl. x. fig. 4.
[1464] Heer (75) ii.
[1465] Halle (132).
Page 787
[1466] Ibid.
[1467] Heer (75) ii. Pls. xiv.–xvi.
[1468] Phillips (29) A. Pl. vii. fig. 22; Pl. x. fig. 4.
[1469] Sternberg (23) A. Pl. xxxiii. fig. 1. For other references, see Seward (00) B. p.
190; (04) B. p. 106.
[1470] Brongniart (28) A. p. 94.
[1471] Lindley and Hutton (35) A. Pl. 172.
[1472] Brongniart (28) A. p. 94.
[1473] Andrae (53) A. Pl. xi. fig. 1.
[1474] Seward (072) p. 29.
[1475] Nathorst (042) B; Halle (132).
[1476] Halle (13).
[1477] Heer (75) ii. p. 66, Pls. xiv., xv.
[1478] Halle (132) p. 58, Pl. vii.
[1479] Ibid. p. 56, Pl. vii.
[1480] Goeppert (44) p. 52.
[1481] Dunker (46) A. p. 14, Pl. ii. fig. 3; Pl. vi. fig. 4.
[1482] Miquel (51) p. 212.
[1483] Seward (95) A. p. 38.
[1484] Schimper (70) A. p. 127.
[1485] Schenk (71) B. Pl. xxxvi.
[1486] Brongniart (28) A. p. 94.
[1487] Schenk (71) B. p. 8.
[1488] Schenk (67) A. Pls. xxxvi.—vii.
[1489] Goeppert (44) p. 122.
[1490] Pomel (47) p. 342.
[1491] Bornemann (56) A. p. 54.
[1492] Nathorst (90) A. p. 46.
[1493] Seward (95) A. p. 75.
[1494] Zeiller (03) B. p. 165.
[1495] Halle (132) p. 55.
[1496] Schimper (72) A. pp. 128, 163.
[1497] Kurr, J. G. (45) B. Pl. i. fig. 5.
[1498] Schenk (71) B. p. 8, Pl. i. fig. 8.
[1499] Saporta (94) B. Pl. xvi.
[1500] Yokoyama (94) Pl. xxi. fig. 5.
[1467] Heer (75) ii. Pls. xiv.–xvi.
[1468] Phillips (29) A. Pl. vii. fig. 22; Pl. x. fig. 4.
[1469] Sternberg (23) A. Pl. xxxiii. fig. 1. For other references, see Seward (00) B. p.
190; (04) B. p. 106.
[1470] Brongniart (28) A. p. 94.
[1471] Lindley and Hutton (35) A. Pl. 172.
[1472] Brongniart (28) A. p. 94.
[1473] Andrae (53) A. Pl. xi. fig. 1.
[1474] Seward (072) p. 29.
[1475] Nathorst (042) B; Halle (132).
[1476] Halle (13).
[1477] Heer (75) ii. p. 66, Pls. xiv., xv.
[1478] Halle (132) p. 58, Pl. vii.
[1479] Ibid. p. 56, Pl. vii.
[1480] Goeppert (44) p. 52.
[1481] Dunker (46) A. p. 14, Pl. ii. fig. 3; Pl. vi. fig. 4.
[1482] Miquel (51) p. 212.
[1483] Seward (95) A. p. 38.
[1484] Schimper (70) A. p. 127.
[1485] Schenk (71) B. Pl. xxxvi.
[1486] Brongniart (28) A. p. 94.
[1487] Schenk (71) B. p. 8.
[1488] Schenk (67) A. Pls. xxxvi.—vii.
[1489] Goeppert (44) p. 122.
[1490] Pomel (47) p. 342.
[1491] Bornemann (56) A. p. 54.
[1492] Nathorst (90) A. p. 46.
[1493] Seward (95) A. p. 75.
[1494] Zeiller (03) B. p. 165.
[1495] Halle (132) p. 55.
[1496] Schimper (72) A. pp. 128, 163.
[1497] Kurr, J. G. (45) B. Pl. i. fig. 5.
[1498] Schenk (71) B. p. 8, Pl. i. fig. 8.
[1499] Saporta (94) B. Pl. xvi.
[1500] Yokoyama (94) Pl. xxi. fig. 5.
Page 788
[1501] Feistmantel (792) p. 18. This statement is based on an examination of the
specimen.
[1502] Zeiller (94) B. p. 174.
[1503] Halle (132) p. 55.
[1504] See page 525.
[1505] Thomas and Bancroft (13) p. 184.
[1506] Zeiller (03) B. p. 166, Pl. xliii. figs. 3–6.
[1507] Brongniart (28) A. p. 94. See Seward (00) B. p. 178.
[1508] Lindley and Hutton (38) A. Pl. clxv.
[1509] Saporta (75) A. Pls. lxxxvii–xcii.
[1510] Ibid. Pls. lxxxiv., lxxxv.
[1511] Ibid. Pl. xciii.
[1512] Saporta (75) A. Pl. xciii.
[1513] Andrae (53) A. Pl. ix.
[1514] Frič and Bayer (01) B. fig. 43, p. 92.
[1515] Hosius and von der March (80) B. Pl. xliv. fig. 202.
[1516] Tate (67) Pl. v. fig. 7.
[1517] Seward (03) B. p. 21, Pls. iii. v.
[1518] No. 11117.
[1519] Seward (95) A. p. 86, Pl. vi.
[1520] Ibid. (112) p. 694, Pl. x. fig. 43.
[1521] Miller (57) B. fig. 136.
[1522] Richards (84) p. 120.
[1523] Ettingshausen (52) B. p. 21, Pl. i. fig. 1; Seward (95) A. p. 79, Pls. iii., iv., viii.
[1524] Goeppert (47) Pl. xxxviii.
[1525] Fontaine (89) B. p. 182, Pls. lxviii.–lxxiv., etc.
[1526] Yokoyama (94) p. 223, Pls. xx., xxiii., etc.
[1527] Nathorst (90) A. Pls. ii., iii., v.
[1528] Braun in Münster (42) B. p. 36.
[1529] Seward (95) A. p. 56.
[1530] Heer (75) ii. Pl. xxvi. fig. 2; the specimen is in the Stockholm Museum.
[1531] Halle (132) p. 55.
[1532] Zigno (85) Pl. xlii. fig. 9.
[1533] Wieland (13).
[1534] Schenk (67) A. Pl. xxxiv. fig. 7.
[1535] Thomas and Bancroft (13) p. 186, Pl. xix. figs. 3, 4.
[1536] Seward (95) A. Pl. i. figs. 1, 2.
specimen.
[1502] Zeiller (94) B. p. 174.
[1503] Halle (132) p. 55.
[1504] See page 525.
[1505] Thomas and Bancroft (13) p. 184.
[1506] Zeiller (03) B. p. 166, Pl. xliii. figs. 3–6.
[1507] Brongniart (28) A. p. 94. See Seward (00) B. p. 178.
[1508] Lindley and Hutton (38) A. Pl. clxv.
[1509] Saporta (75) A. Pls. lxxxvii–xcii.
[1510] Ibid. Pls. lxxxiv., lxxxv.
[1511] Ibid. Pl. xciii.
[1512] Saporta (75) A. Pl. xciii.
[1513] Andrae (53) A. Pl. ix.
[1514] Frič and Bayer (01) B. fig. 43, p. 92.
[1515] Hosius and von der March (80) B. Pl. xliv. fig. 202.
[1516] Tate (67) Pl. v. fig. 7.
[1517] Seward (03) B. p. 21, Pls. iii. v.
[1518] No. 11117.
[1519] Seward (95) A. p. 86, Pl. vi.
[1520] Ibid. (112) p. 694, Pl. x. fig. 43.
[1521] Miller (57) B. fig. 136.
[1522] Richards (84) p. 120.
[1523] Ettingshausen (52) B. p. 21, Pl. i. fig. 1; Seward (95) A. p. 79, Pls. iii., iv., viii.
[1524] Goeppert (47) Pl. xxxviii.
[1525] Fontaine (89) B. p. 182, Pls. lxviii.–lxxiv., etc.
[1526] Yokoyama (94) p. 223, Pls. xx., xxiii., etc.
[1527] Nathorst (90) A. Pls. ii., iii., v.
[1528] Braun in Münster (42) B. p. 36.
[1529] Seward (95) A. p. 56.
[1530] Heer (75) ii. Pl. xxvi. fig. 2; the specimen is in the Stockholm Museum.
[1531] Halle (132) p. 55.
[1532] Zigno (85) Pl. xlii. fig. 9.
[1533] Wieland (13).
[1534] Schenk (67) A. Pl. xxxiv. fig. 7.
[1535] Thomas and Bancroft (13) p. 186, Pl. xix. figs. 3, 4.
[1536] Seward (95) A. Pl. i. figs. 1, 2.
Page 789
[1537] Brongniart (25) Pl. xix. fig. 4; Seward (00) B. p. 219; (04) B. p. 39.
[1538] Lindley and Hutton (34) A. Pl. cxxviii.
[1539] Zeiller (12) p. 6; Halle (132) p. 63 (footnote).
[1540] Seward (00) B. p. 218.
[1541] Leckenby (64) A. Pl. viii. fig. 5; Seward (00) B. p. 213, Pls. i., ii.
[1542] Zigno (81) Pl. xxxiii. figs. 3, 4.
[1543] Saporta (75) A. PL. 101.
[1544] Ibid. Pl. 99.
[1545] Halle (132) Pl. vii.
[1546] Heer (75) ii. Pl. xvi. figs. 5–8.
[1547] Schenk (67) A. Pls. xxxiii., xxxiv.
[1548] Zeiller (03) B. Pl. xliii. fig. 1.
[1549] Krasser (91) p. 12.
[1550] Zeiller (05).
[1551] Lindley and Hutton (32) A. Pl. xliv.
[1552] Leckenby (64) A. Pl. x. fig. 2.
[1553] Zigno (85) Pls. xxxv.–xxxvi.
[1554] Zigno (53) p. 11; Seward (00) B. p. 211.
[1555] Leckenby (64) A. Pl. ix. fig. 3.
[1556] Feistmantel (79) Pls. vii., xvi.
[1557] Möller (03) Pl. i.
[1558] Zigno (81) Pl. xxiv.; Thomas and Bancroft (13) p. 186; Seward (00) B. p. 221.
[1559] Oldham and Morris (63) B. p. 27, Pl. xix.; Feistmantel (762) Pl. vii. fig. 4.
[1560] Dunker (46) A. p. 11, Pl. ix. figs. 6, 7; Seward (95) A. p. 60.
[1561] Saporta (75) A. Pls. cx., cxi.
[1562] Ibid. Pl. cx.
[1563] Thomas (11) p. 83, Pls. v., vi.
[1564] Fontaine in Ward (05) B. Pl. xxxviii.
[1565] Nathorst (13) p. 279.
[1566] Dunker (46) A. p. 14, Pl. ii. fig. 5; Seward (95) A. p. 70, Pl. i.
[1567] Oldham and Morris (63) B. p. 37.
[1568] Seward (03).
[1569] Yabe (05) B. Pl. ii. figs. 2–7.
[1570] Halle (12); (13) p. 9, Pl. v. figs. 29–33.
[1571] Bancroft (13).
[1572] Oldham and Morris (63) B. Pl. xxiv. figs. 1, 2; Feistmantel (762) Pls. iv.–vi.; (77)
Pl. ii.
[1538] Lindley and Hutton (34) A. Pl. cxxviii.
[1539] Zeiller (12) p. 6; Halle (132) p. 63 (footnote).
[1540] Seward (00) B. p. 218.
[1541] Leckenby (64) A. Pl. viii. fig. 5; Seward (00) B. p. 213, Pls. i., ii.
[1542] Zigno (81) Pl. xxxiii. figs. 3, 4.
[1543] Saporta (75) A. PL. 101.
[1544] Ibid. Pl. 99.
[1545] Halle (132) Pl. vii.
[1546] Heer (75) ii. Pl. xvi. figs. 5–8.
[1547] Schenk (67) A. Pls. xxxiii., xxxiv.
[1548] Zeiller (03) B. Pl. xliii. fig. 1.
[1549] Krasser (91) p. 12.
[1550] Zeiller (05).
[1551] Lindley and Hutton (32) A. Pl. xliv.
[1552] Leckenby (64) A. Pl. x. fig. 2.
[1553] Zigno (85) Pls. xxxv.–xxxvi.
[1554] Zigno (53) p. 11; Seward (00) B. p. 211.
[1555] Leckenby (64) A. Pl. ix. fig. 3.
[1556] Feistmantel (79) Pls. vii., xvi.
[1557] Möller (03) Pl. i.
[1558] Zigno (81) Pl. xxiv.; Thomas and Bancroft (13) p. 186; Seward (00) B. p. 221.
[1559] Oldham and Morris (63) B. p. 27, Pl. xix.; Feistmantel (762) Pl. vii. fig. 4.
[1560] Dunker (46) A. p. 11, Pl. ix. figs. 6, 7; Seward (95) A. p. 60.
[1561] Saporta (75) A. Pls. cx., cxi.
[1562] Ibid. Pl. cx.
[1563] Thomas (11) p. 83, Pls. v., vi.
[1564] Fontaine in Ward (05) B. Pl. xxxviii.
[1565] Nathorst (13) p. 279.
[1566] Dunker (46) A. p. 14, Pl. ii. fig. 5; Seward (95) A. p. 70, Pl. i.
[1567] Oldham and Morris (63) B. p. 37.
[1568] Seward (03).
[1569] Yabe (05) B. Pl. ii. figs. 2–7.
[1570] Halle (12); (13) p. 9, Pl. v. figs. 29–33.
[1571] Bancroft (13).
[1572] Oldham and Morris (63) B. Pl. xxiv. figs. 1, 2; Feistmantel (762) Pls. iv.–vi.; (77)
Pl. ii.
Page 790
[1573] Yokoyama (89) B, Pl. vii. fig. 10; Pls. x., xi.
[1574] Seward (03) p. 217.
[1575] The statement made by me [Seward (114) p. 3] that Dictyozamites occurs in the
Falklands is incorrect.
[1576] Nathorst (89); Möller (03) p. 25, Pl. v.
[1577] Nathorst (072) Pl. iii. figs. 2–8.
[1578] Seward (03); Thomas (132) p. 238; Thomas and Bancroft (13) p. 186, Pl. xix.
figs. 6–8.
[1579] Brongniart (25).
[1580] Nathorst (81) p. 61.
[1581] Brongniart (28) A. p. 95.
[1582] Heer (75) ii. Pl. xv. fig. 11.
[1583] Schimper (72) A. p. 140.
[1584] Potonié (99) B. p. 281.
[1585] Zeiller (03) B. p. 174.
[1586] Halle (15) p. 515, Pl. xiii. figs. 18–20, 22.
[1587] Heer (76) A. Pl. xxxv. fig. 3.
[1588] Leuthardt (03) p. 20.
[1589] See page 463.
[1590] Thomas (132) p. 237.
[1591] Schenk (67) A. Pls. xxxvii.–viii.
[1592] Ibid. Pl. xxxix. fig. 7.
[1593] Thomas and Bancroft (13) Pl. xix. fig. 5.
[1594] Ettingshausen (86) Pl. viii. figs. 19–21.
[1595] Renault and Zeiller (88) A. p. 619, Pl. lxviii.
[1596] Arber, E. A. N. (122).
[1597] Sandberger (64) Pl. ii. figs. 1–4.
[1598] Renault (96) A. p. 322, fig. 64.
[1599] Saporta and Marion (85) p. 109, fig. 58 A.
[1600] Sandberger (64) Pl. ii. figs. 1–4.
[1601] Geinitz (73) Pl. iii. fig. 9.
[1602] Geinitz fig. 8.
[1603] Brongniart (28) p. 95.
[1604] Leuthardt (03) p. 14, Pl. v.
[1605] Ibid. p. 16, Pl. v.
[1606] Ibid. Pl. vii. fig. 4; Pl. viii. figs. 3–5.
[1607] Krasser (09).
[1574] Seward (03) p. 217.
[1575] The statement made by me [Seward (114) p. 3] that Dictyozamites occurs in the
Falklands is incorrect.
[1576] Nathorst (89); Möller (03) p. 25, Pl. v.
[1577] Nathorst (072) Pl. iii. figs. 2–8.
[1578] Seward (03); Thomas (132) p. 238; Thomas and Bancroft (13) p. 186, Pl. xix.
figs. 6–8.
[1579] Brongniart (25).
[1580] Nathorst (81) p. 61.
[1581] Brongniart (28) A. p. 95.
[1582] Heer (75) ii. Pl. xv. fig. 11.
[1583] Schimper (72) A. p. 140.
[1584] Potonié (99) B. p. 281.
[1585] Zeiller (03) B. p. 174.
[1586] Halle (15) p. 515, Pl. xiii. figs. 18–20, 22.
[1587] Heer (76) A. Pl. xxxv. fig. 3.
[1588] Leuthardt (03) p. 20.
[1589] See page 463.
[1590] Thomas (132) p. 237.
[1591] Schenk (67) A. Pls. xxxvii.–viii.
[1592] Ibid. Pl. xxxix. fig. 7.
[1593] Thomas and Bancroft (13) Pl. xix. fig. 5.
[1594] Ettingshausen (86) Pl. viii. figs. 19–21.
[1595] Renault and Zeiller (88) A. p. 619, Pl. lxviii.
[1596] Arber, E. A. N. (122).
[1597] Sandberger (64) Pl. ii. figs. 1–4.
[1598] Renault (96) A. p. 322, fig. 64.
[1599] Saporta and Marion (85) p. 109, fig. 58 A.
[1600] Sandberger (64) Pl. ii. figs. 1–4.
[1601] Geinitz (73) Pl. iii. fig. 9.
[1602] Geinitz fig. 8.
[1603] Brongniart (28) p. 95.
[1604] Leuthardt (03) p. 14, Pl. v.
[1605] Ibid. p. 16, Pl. v.
[1606] Ibid. Pl. vii. fig. 4; Pl. viii. figs. 3–5.
[1607] Krasser (09).
Page 791
[1608] Schenk (67) Pl. ii. There are some fine examples from the Raibl beds in the
Vienna Geological Survey Collection.
[1609] Arber (07).
[1610] Fontaine (83) B. p. 80, Pls. xliii.–v.
[1611] Schimper (72) A. pp. 127, 132.
[1612] Schenk (67) Pl. ii.
[1613] Goeppert (44); Schenk (67) A. p. 164, Pl. xxxviii.
[1614] Schenk (87) B. p. 6, Pls. vi., ix.
[1615] Zeiller (03) B. p. 189, Pl. xlvii. fig. 1.
[1616] Zeiller (03) B. p. 198, Pl. xlix. figs. 1–3.
[1617] Ibid. (05) p. 194.
[1618] Braun, F. (43).
[1619] Zeiller (03) B. p. 177, Pl. xliii. fig. 8; Pl. xliv. figs. 1–5.
[1620] Schenk (67) A. Pl. xxxviii. figs. 5–9.
[1621] Zeiller (03) B. Pl. xliii. fig. 7.
[1622] Feistmantel (86) Pl. ii. A. figs. 4–8.
[1623] Seward (00) B. p. 239.
[1624] Seward (112) p. 694, Pls. iv., v. etc.
[1625] Zeiller (03) B. Pl. xix.
[1626] Fontaine in Ward (05) B. Pl. xxii.
[1627] Schenk (71) B. Pl. xxiv. fig. 5.
[1628] Oldham and Morris (63) B. Pl. ix.; Feistmantel (773) Pls. v., vi.
[1629] Phillips (29) A. Pl. viii. fig. 4.
[1630] See Seward (00) B. p. 204.
[1631] Dunker (46) A. p. 14, Pl. vi. figs. 1, 2.
[1632] Seward (95) A. p. 91; see also Schenk (71) Pl. xxxiv.
[1633] Sternberg (25) A. p. xxxii.
[1634] Brongniart (28) A. p. 93. Specimens named by Brongniart Cycadites Nilssoniana
are probably fragments of Dicotyledonous leaves [Nathorst (81) p. 83].
[1635] Holden, R. (142).
[1636] Nathorst (073).
[1637] Halle (15).
[1638] Pls. xii., xiii.
[1639] Thomas and Bancroft (13).
[1640] Heer (82) B. Pl. v.
[1641] Ibid. (78) ii. Pl. iv. fig. 1; Nathorst (972) p. 387.
[1642] Heer (77) ii. Pls. viii., xxiii., xxv.
Vienna Geological Survey Collection.
[1609] Arber (07).
[1610] Fontaine (83) B. p. 80, Pls. xliii.–v.
[1611] Schimper (72) A. pp. 127, 132.
[1612] Schenk (67) Pl. ii.
[1613] Goeppert (44); Schenk (67) A. p. 164, Pl. xxxviii.
[1614] Schenk (87) B. p. 6, Pls. vi., ix.
[1615] Zeiller (03) B. p. 189, Pl. xlvii. fig. 1.
[1616] Zeiller (03) B. p. 198, Pl. xlix. figs. 1–3.
[1617] Ibid. (05) p. 194.
[1618] Braun, F. (43).
[1619] Zeiller (03) B. p. 177, Pl. xliii. fig. 8; Pl. xliv. figs. 1–5.
[1620] Schenk (67) A. Pl. xxxviii. figs. 5–9.
[1621] Zeiller (03) B. Pl. xliii. fig. 7.
[1622] Feistmantel (86) Pl. ii. A. figs. 4–8.
[1623] Seward (00) B. p. 239.
[1624] Seward (112) p. 694, Pls. iv., v. etc.
[1625] Zeiller (03) B. Pl. xix.
[1626] Fontaine in Ward (05) B. Pl. xxii.
[1627] Schenk (71) B. Pl. xxiv. fig. 5.
[1628] Oldham and Morris (63) B. Pl. ix.; Feistmantel (773) Pls. v., vi.
[1629] Phillips (29) A. Pl. viii. fig. 4.
[1630] See Seward (00) B. p. 204.
[1631] Dunker (46) A. p. 14, Pl. vi. figs. 1, 2.
[1632] Seward (95) A. p. 91; see also Schenk (71) Pl. xxxiv.
[1633] Sternberg (25) A. p. xxxii.
[1634] Brongniart (28) A. p. 93. Specimens named by Brongniart Cycadites Nilssoniana
are probably fragments of Dicotyledonous leaves [Nathorst (81) p. 83].
[1635] Holden, R. (142).
[1636] Nathorst (073).
[1637] Halle (15).
[1638] Pls. xii., xiii.
[1639] Thomas and Bancroft (13).
[1640] Heer (82) B. Pl. v.
[1641] Ibid. (78) ii. Pl. iv. fig. 1; Nathorst (972) p. 387.
[1642] Heer (77) ii. Pls. viii., xxiii., xxv.
Page 792
[1643] Oldham and Morris (63) B. Pls. vii., viii.; Feistmantel (772) Pl. xlviii. fig. 1; the
drawing is very inaccurate.
[1644] Oldham and Morris (63) B. Pl. ix.
[1645] Feistmantel (79) Pl. vii. fig. 10; Nathorst (09) p. 5, note 2.
[1646] Goeppert (66).
[1647] Zeiller (02) B. Pl. vii. fig. 4.
[1648] Nathorst (073) Pls. i.–iii.
[1649] Seward (95) A. p 29, Pl. ii. fig. 7; Pl. vi. fig. 5; Pl. viii. fig. 2.
[1650] Saporta (94) B. p. 171, Pl. xxxii.
[1651] Holden, R. (142).
[1652] Halle (55), p. 502.
[1653] Schenk (71) B. Pl. xxxii. fig. 1.
[1654] Seward (95) A. pp. 2–7.
[1655] Halle (15), Pl. xii. fig. 12.
[1656] Zeiller (03) B. p. 155, Pl. xli.
[1657] Brauns (66) p. 56, Pl. xiv. fig. 7; Schenk (67) A. Pl. xxxv. fig. 11; Seward (04) B.
p. 37, Pl. iv. fig. 4; Pl. ii. fig. 1.
[1658] Lignier (13) p. 90, Pl. ix. figs. 18, 19.
[1659] Brongniart (25).
[1660] Nathorst (092).
[1661] Pages 13, 16.
[1662] Nathorst (092); Thomas and Bancroft (13).
[1663] Stopes (102).
[1664] Schenk (67) A. Pl. xxix. figs. 1, 2.
[1665] See vol. iv.
[1666] Nathorst (86) Pl. xviii. fig. 5.
[1667] Ibid. (092) p. 28.
[1668] Thomas (132) p. 241; Thomas and Bancroft (13) p. 193.
[1669] Miquel (42) p. 61.
[1670] Schenk (67) A. p. 127, Pls. xxix., xxx.; Nathorst (092) p. 10, Pl. v. figs. 9–13, etc.
[1671] For other references see Nathorst (092) p. 10.
[1672] Brongniart (25) p. 218.
[1673] Nathorst (092) p. 12, Pl. i. figs. 2–35, etc.
[1674] Oldham and Morris (63) Pls. vii., viii.
[1675] Feistmantel (773) p. 124.
[1676] Schenk (67) A. Pl. xxix. fig. 10.
drawing is very inaccurate.
[1644] Oldham and Morris (63) B. Pl. ix.
[1645] Feistmantel (79) Pl. vii. fig. 10; Nathorst (09) p. 5, note 2.
[1646] Goeppert (66).
[1647] Zeiller (02) B. Pl. vii. fig. 4.
[1648] Nathorst (073) Pls. i.–iii.
[1649] Seward (95) A. p 29, Pl. ii. fig. 7; Pl. vi. fig. 5; Pl. viii. fig. 2.
[1650] Saporta (94) B. p. 171, Pl. xxxii.
[1651] Holden, R. (142).
[1652] Halle (55), p. 502.
[1653] Schenk (71) B. Pl. xxxii. fig. 1.
[1654] Seward (95) A. pp. 2–7.
[1655] Halle (15), Pl. xii. fig. 12.
[1656] Zeiller (03) B. p. 155, Pl. xli.
[1657] Brauns (66) p. 56, Pl. xiv. fig. 7; Schenk (67) A. Pl. xxxv. fig. 11; Seward (04) B.
p. 37, Pl. iv. fig. 4; Pl. ii. fig. 1.
[1658] Lignier (13) p. 90, Pl. ix. figs. 18, 19.
[1659] Brongniart (25).
[1660] Nathorst (092).
[1661] Pages 13, 16.
[1662] Nathorst (092); Thomas and Bancroft (13).
[1663] Stopes (102).
[1664] Schenk (67) A. Pl. xxix. figs. 1, 2.
[1665] See vol. iv.
[1666] Nathorst (86) Pl. xviii. fig. 5.
[1667] Ibid. (092) p. 28.
[1668] Thomas (132) p. 241; Thomas and Bancroft (13) p. 193.
[1669] Miquel (42) p. 61.
[1670] Schenk (67) A. p. 127, Pls. xxix., xxx.; Nathorst (092) p. 10, Pl. v. figs. 9–13, etc.
[1671] For other references see Nathorst (092) p. 10.
[1672] Brongniart (25) p. 218.
[1673] Nathorst (092) p. 12, Pl. i. figs. 2–35, etc.
[1674] Oldham and Morris (63) Pls. vii., viii.
[1675] Feistmantel (773) p. 124.
[1676] Schenk (67) A. Pl. xxix. fig. 10.
Page 793
[1677] Stopes (102).
[1678] Nathorst (86) p. 72.
[1679] Ibid. (02) p. 18, Pl. i.
[1680] Ibid. (092) p. 21, Pls. vi., vii.
[1681] Phillips (29) A. p. 148, Pl. vii. fig. 20. See Seward (00) B, p. 223, Pl. iv. fig. 5;
text figs. 39, 40.
[1682] Thomas and Bancroft (13) p. 191.
[1683] A specimen in the Natural History Museum, Paris, labelled N. Williamsonis is
probably that mentioned by Brongniart.
[1684] Oldham and Morris (63) B. Pls. x.–xiii.; Feistmantel (77) Pl. xlvii.
[1685] Heer (78) ii. Pls. xxiii., xxiv.; Seward (123) p. 27, Pl. ii.
[1686] Nathorst (97) p. 13.
[1687] Yokoyama (89) B. Pls. v., vii., xii., xiii.; Ward (05) B. Pl. xvii.
[1688] Heer (78) ii. p. 18, Pl. iv. figs. 5–9.
[1689] Seward (00) B. p. 230, fig. 41.
[1690] Heer (82) B. Pl. vi.
[1691] For figures and references, see Seward (112) p. 695; Thomas (11) p. 86.
[1692] Halle (132) p. 47, Pls. v., vi.
[1693] Fontaine (89) B. Pls. xxx.–xxxv.
[1694] Berry (11) p. 362, Pls. lvii., lviii.
[1695] Seward (00) B. p. 224.
[1696] Nathorst (97) Pl. i. fig. 18.
[1697] Seward (12) p. 30.
[1698] Yokoyama (89) B.; Nathorst (90) A.
[1699] Stopes (102).
[1700] Salfield (09) B. Pl. iii. figs. 5–7.
[1701] For references, see Seward (12) p. 31.
[1702] Phillips (29) A. p. 148, Pl. vii. fig. 19.
[1703] Leckenby (64) A. p. 77; Seward (00) B. p. 227, Pl. iv. figs. 1–4.
[1704] Seward (00) B. p. 227.
[1705] Krasser (09) p. 120.
[1706] Seward (112) p. 697.
[1707] Oldham and Morris (63) B. p. 23, Pls. x.–xiii.; Feistmantel (77) Pl. xlvii.
[1708] Oldham and Morris (63) B. Pl. xv. fig. 1.
[1709] Dunker (46) A. p. 15, Pl. i. fig. 7, etc.; Seward (95) A. p. 53.
[1710] Schenk (71) B.; Nathorst (90) A.; Yokoyama (94); Fontaine in Ward (05) B.; Yabe
(13).
[1678] Nathorst (86) p. 72.
[1679] Ibid. (02) p. 18, Pl. i.
[1680] Ibid. (092) p. 21, Pls. vi., vii.
[1681] Phillips (29) A. p. 148, Pl. vii. fig. 20. See Seward (00) B, p. 223, Pl. iv. fig. 5;
text figs. 39, 40.
[1682] Thomas and Bancroft (13) p. 191.
[1683] A specimen in the Natural History Museum, Paris, labelled N. Williamsonis is
probably that mentioned by Brongniart.
[1684] Oldham and Morris (63) B. Pls. x.–xiii.; Feistmantel (77) Pl. xlvii.
[1685] Heer (78) ii. Pls. xxiii., xxiv.; Seward (123) p. 27, Pl. ii.
[1686] Nathorst (97) p. 13.
[1687] Yokoyama (89) B. Pls. v., vii., xii., xiii.; Ward (05) B. Pl. xvii.
[1688] Heer (78) ii. p. 18, Pl. iv. figs. 5–9.
[1689] Seward (00) B. p. 230, fig. 41.
[1690] Heer (82) B. Pl. vi.
[1691] For figures and references, see Seward (112) p. 695; Thomas (11) p. 86.
[1692] Halle (132) p. 47, Pls. v., vi.
[1693] Fontaine (89) B. Pls. xxx.–xxxv.
[1694] Berry (11) p. 362, Pls. lvii., lviii.
[1695] Seward (00) B. p. 224.
[1696] Nathorst (97) Pl. i. fig. 18.
[1697] Seward (12) p. 30.
[1698] Yokoyama (89) B.; Nathorst (90) A.
[1699] Stopes (102).
[1700] Salfield (09) B. Pl. iii. figs. 5–7.
[1701] For references, see Seward (12) p. 31.
[1702] Phillips (29) A. p. 148, Pl. vii. fig. 19.
[1703] Leckenby (64) A. p. 77; Seward (00) B. p. 227, Pl. iv. figs. 1–4.
[1704] Seward (00) B. p. 227.
[1705] Krasser (09) p. 120.
[1706] Seward (112) p. 697.
[1707] Oldham and Morris (63) B. p. 23, Pls. x.–xiii.; Feistmantel (77) Pl. xlvii.
[1708] Oldham and Morris (63) B. Pl. xv. fig. 1.
[1709] Dunker (46) A. p. 15, Pl. i. fig. 7, etc.; Seward (95) A. p. 53.
[1710] Schenk (71) B.; Nathorst (90) A.; Yokoyama (94); Fontaine in Ward (05) B.; Yabe
(13).
Page 794
[1711] Lindley and Hutton (34) A. Pl. ciii.; Phillips (29) A. Pl. vii. fig. 21.
[1712] Zeiller (00) B. p. 115; Krasser (09) p. 113.
[1713] Ettingshausen (51).
[1712] Zeiller (00) B. p. 115; Krasser (09) p. 113.
[1713] Ettingshausen (51).
Page 795
[1714] Schenk (682).
[1715] Raciborski (94) A. Pls. xvii.–xix.
[1716] Staub (96).
[1717] Nathorst (86) p. 43.
[1718] Seward (00) p. 21; (00) B. p. 232, figs. 42, 43.
[1719] Raciborski (94) A. Pl. xvi.
[1720] Fontaine (89) B. p. 174, Pls. lxx.–lxxii.
[1721] Krasser (09) p. 113.
[1722] Nathorst (86) p. 89, Pls. vii., viii., xi., xix.
[1723] Raciborski (92) Pl. ii. fig. 2.
[1724] Staub (96)
[1725] Ettingshausen (51) Pls. xi., xii.
[1726] Schenk (682).
[1727] Raciborski (92) Pl. ii. fig. 2.
[1728] Ibid. (94) A. Pl. xviii. fig. 2.
[1729] Yokoyama (06) B. Pl. ix.
[1730] Phillips (29) A. p. 148, Pl. vii. fig. 21.
[1731] Lindley and Hutton (34) A. Pl. ciii.
[1732] Ward (05) B. p. 113.
[1733] Seward (00) B. p. 235, Pl. viii. fig. 2; Zigno (56) A. Pl. xxiv.
[1734] Fontaine in Ward (05) B. Pls. xxvii.–xxviii.
[1735] Seward (12) Pl. iii. fig. 43.
[1736] Seward (04) B. p. 115.
[1737] Ibid. (00) p. 21.
[1738] Seward (112) p. 691.
[1739] Ibid. p. 792, Pls. iv., vii., viii., x.
[1740] Miller (57) B. figs. 133, 135.
[1741] Richards (84) p. 117.
[1742] Seward (95) A. p. 89, fig. 5.
[1743] Tate (67) Pl. v. fig. 3; Seward (03) B. Pl. v. fig. 3.
[1744] Fontaine (83) B. Pls. xxxix.–xlii.
[1745] Fontaine in Ward (05) B. Pl. xxiii.
[1746] Seward (112) Pls. iv., vii.
[1747] Halle (132) p. 51, Pl. vi. fig. 8.
[1715] Raciborski (94) A. Pls. xvii.–xix.
[1716] Staub (96).
[1717] Nathorst (86) p. 43.
[1718] Seward (00) p. 21; (00) B. p. 232, figs. 42, 43.
[1719] Raciborski (94) A. Pl. xvi.
[1720] Fontaine (89) B. p. 174, Pls. lxx.–lxxii.
[1721] Krasser (09) p. 113.
[1722] Nathorst (86) p. 89, Pls. vii., viii., xi., xix.
[1723] Raciborski (92) Pl. ii. fig. 2.
[1724] Staub (96)
[1725] Ettingshausen (51) Pls. xi., xii.
[1726] Schenk (682).
[1727] Raciborski (92) Pl. ii. fig. 2.
[1728] Ibid. (94) A. Pl. xviii. fig. 2.
[1729] Yokoyama (06) B. Pl. ix.
[1730] Phillips (29) A. p. 148, Pl. vii. fig. 21.
[1731] Lindley and Hutton (34) A. Pl. ciii.
[1732] Ward (05) B. p. 113.
[1733] Seward (00) B. p. 235, Pl. viii. fig. 2; Zigno (56) A. Pl. xxiv.
[1734] Fontaine in Ward (05) B. Pls. xxvii.–xxviii.
[1735] Seward (12) Pl. iii. fig. 43.
[1736] Seward (04) B. p. 115.
[1737] Ibid. (00) p. 21.
[1738] Seward (112) p. 691.
[1739] Ibid. p. 792, Pls. iv., vii., viii., x.
[1740] Miller (57) B. figs. 133, 135.
[1741] Richards (84) p. 117.
[1742] Seward (95) A. p. 89, fig. 5.
[1743] Tate (67) Pl. v. fig. 3; Seward (03) B. Pl. v. fig. 3.
[1744] Fontaine (83) B. Pls. xxxix.–xlii.
[1745] Fontaine in Ward (05) B. Pl. xxiii.
[1746] Seward (112) Pls. iv., vii.
[1747] Halle (132) p. 51, Pl. vi. fig. 8.
Page 796
[1748] Berry (11) p. 349.
[1749] Oldham and Morris (63) Pl. xv. fig. 4.
[1750] Ibid. Pl. xv. fig. 1.; Feistmantel (77) Pl. xliii. fig. 1.
[1751] Thomas (132) p. 242, Pls. xxiv., xxvi.
[1752] Ibid. Pl. xxvi.
[1753] Feistmantel (86) Pl. ii. A. figs. 4–8.
[1754] Brongniart (49) A. p. 61.
[1755] Zigno (85) p. 105.
[1756] Seward (00) B. p. 215.
[1757] Renault (96) A. p. 327; (93) A. Pl. lxxxi. fig. 1.
[1758] Seward (04) B. p. 119, Pl. xi. fig. 4, text-fig. 12.
[1759] Buckman (45) Pl. i. fig. 2.
[1760] Zigno (85) Pls. xxxix., xl.
[1761] Newberry (88) Pl. viii. fig. 14.
[1762] See vol. iv.
[1763] Bodenbender (02) p. 40 of the reprint.
[1764] Zeiller (94) B. p. 174, Pls. viii., ix.
[1765] Renault and Zeiller (88) A. p. 614, Pl. lxvii. fig. 8.
[1766] Zalessky (052) p. 401, fig. 13.
[1767] Potonié (93) A. p. 210, Pl. xxix. fig. 5.
[1768] Zalessky (052) p. 403, figs. 14, 15.
[1769] Bassler (16).
[1770] Saporta (75) A. p. 193, Pl. 114, fig. 3; Pl. 117, fig. 1.
[1771] Fliche and Bleicher (82) p. 21, fig. 4.
[1772] Stopes (15) p. 53.
[1749] Oldham and Morris (63) Pl. xv. fig. 4.
[1750] Ibid. Pl. xv. fig. 1.; Feistmantel (77) Pl. xliii. fig. 1.
[1751] Thomas (132) p. 242, Pls. xxiv., xxvi.
[1752] Ibid. Pl. xxvi.
[1753] Feistmantel (86) Pl. ii. A. figs. 4–8.
[1754] Brongniart (49) A. p. 61.
[1755] Zigno (85) p. 105.
[1756] Seward (00) B. p. 215.
[1757] Renault (96) A. p. 327; (93) A. Pl. lxxxi. fig. 1.
[1758] Seward (04) B. p. 119, Pl. xi. fig. 4, text-fig. 12.
[1759] Buckman (45) Pl. i. fig. 2.
[1760] Zigno (85) Pls. xxxix., xl.
[1761] Newberry (88) Pl. viii. fig. 14.
[1762] See vol. iv.
[1763] Bodenbender (02) p. 40 of the reprint.
[1764] Zeiller (94) B. p. 174, Pls. viii., ix.
[1765] Renault and Zeiller (88) A. p. 614, Pl. lxvii. fig. 8.
[1766] Zalessky (052) p. 401, fig. 13.
[1767] Potonié (93) A. p. 210, Pl. xxix. fig. 5.
[1768] Zalessky (052) p. 403, figs. 14, 15.
[1769] Bassler (16).
[1770] Saporta (75) A. p. 193, Pl. 114, fig. 3; Pl. 117, fig. 1.
[1771] Fliche and Bleicher (82) p. 21, fig. 4.
[1772] Stopes (15) p. 53.
Page 797
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