Home / Introductions to both Fossil and Recent Plant Taxa / Pteridospermopsida

A. Abu Hamad et al. (2017): Dicroidium bandelii sp. nov. (corystospermalean foliage) from the Permian of Jordan. In PDF, PalZ, 91: 641–648. See also here.

D. Agnihotri et al. (2024): Satpuraphyllum furcatum—a new genus and species of Peltaspermales foliage from the mid-Permian Barakar Formation of India. Free access, Alcheringa: An Australasian Journal of Palaeontology, DOI: 10.1080/03115518.2024.2415097.

H.M. Anderson-Holmes (2024): The cupule Kannaskoppia from the Upper Triassic, Molteno Flora, Gondwana: Exploring the whole plant and habitat. YouTube video lecture. A paleobotanical online workshop (about half an hour long), followed by a discussion.
Insights into the study of the Molteno flora of South Africa.

H.M. Anderson et al. (2008): Stems with attached Dicroidium leaves from the Ipswich Coal Measures, Queensland, Australia. PDF file, Memoirs of the Queensland Museum 52: 1-12. Snapshot taken by the Internet Archive´s Wayback Machine.

S. Archangelsky (1968): Studies on Triassic fossil plants from Argentina. IV. The leaf genus Dicroidium and its possible relation to Rhexoxylon stems. PDF file, Palaeontology.
The link is to a version archived by the Internet Archive´s Wayback Machine.

S. Archangelsky (1968): Studies on Triassic fossil plants from Argentina. IV. The leaf genus Dicroidium and its possible relation to Rhexoxylon stems. PDF file, Palaeontology.
The link is to a version archived by the Internet Archive´s Wayback Machine.

E. Artabe et al. (1999): Rhexoxylon brunoi Artabe, Brea et Zamuner, sp. nov., a new Triassic corystosperm from the Paramillo de Uspallata, Mendoza, Argentina. In PDF, Rev. Palaeobot. Palynol., 105: 63–74.

Brian J. Axsmith et al. (2007): The "New Approach to Corystospermales" and the Antarctic Fossil Record: A Critique. Ameghiniana, 44. See also here (PDF file).

B.J. Axsmith et al. (2000): New perspectives on the Mesozoic seed fern order Corystospermales based on attached organs from the Triassic of Antarctica. Free access, American Journal of Botany, 87: 757-768.
Note Fig. 21: Reconstruction of an Umkomasia uniramia cupulate organ.

M. Backer et al. (2019): Frond morphology and epidermal anatomy of Compsopteris wongii (T. Halle) Zalessky from the Permian of Shanxi, China. Open access, PalZ.

R. Barboni et al. (2016): Xylopteris (Frenguelli) Stipanicic & Bonetti in the Middle-Upper Triassic (Santa Maria Formation) of Brazil. In PDF, Ameghiniana, 53: 599-622. See also here.

The Museum of Paleontology (UCMP), University of California at Berkeley: Introduction to the Glossopteridales.

B. Bomfleur et al. (2018): Polar Regions of the Mesozoic-Paleogene Greenhouse World as Refugia for Relict Plant Groups. Chapter 24, in PDF, in: M. Krings, C.J. Harper, N.R. Cuneo and G.W. Rothwell (eds.): Transformative Paleobotany Papers to Commemorate the Life and Legacy of Thomas N. Taylor.
Note figure 24.2: Distribution of Dicroidium through space and time.

B. Bomfleur et al. (2012): Modified basal elements in Dicroidium fronds (Corystospermales). In PDF, Review of Palaeobotany and Palynology, 170: 15-26.
See also here.

B. Bomfleur et al. (2011): Systematics and paleoecology of a new peltaspermalean seed fern from the Triassic polar vegetation of Gondwana. In PDF, International Journal of Plant Sciences, 172: 807-835.
See also here.

L.D. Boucher et al. (1995): Dicroidium compression floras from southern Victoria Land. PDF file, Antarctic Journal, 41.
See also here.

Philippe Choler, Laboratoire de Biologie des Populations d'Altitude, Université Joseph Fourier, Grenoble: Biologie Evolutive Végétale. Concepts and methods in evolutionary biology (in French).
Navigate from "Plan du cours" (access to about 335 slides).
Go to: Corystospermaceae, or Caytoniales.
These expired links are available through the Internet Archive´s Wayback Machine.

! C.J. Cleal and B.A. Thomas (2023): Taxonomy and nomenclature of Sphenopteris and allied fossil-genera of Carboniferous seed-plant fronds. Free access, Taxon, 72: 862–879.
Note figure 10: Taxonomy and nomenclature of Sphenopteris and allied fossil-genera of Carboniferous seed-plant fronds.
"... Eight fossil-genera of lyginopteridalean fronds are now recognised (Sphenopteris, Calymmotheca, Eusphenopteris, Karinopteris, Mariopteris, Palmatopteris, Spathulopteris, Sphenopteridium) ..."

! C.J. Cleal and B.A. Thomas (2023): Taxonomy and nomenclature of Sphenopteris and allied fossil-genera of Carboniferous seed-plant fronds. Open access, Taxon, 72: 717-964.

C.J. Cleal (2022): The Craigleith Tree. In PDF.
"... The Craigleith Tree (Pitys withamii Tree) was a species of early seed plant, belonging to the general group known as the hydrasperman pteridosperms
[...] which indicate an early Asbian / late Visean age
[...] The trees were at least 20 m tall, with a trunk up to 1 m wide at the base, and were the tallest known woody trees growing anywhere in the world at this time.

C.J. Cleal et al. (2015): Pennsylvanian fossil flora from the Velebit Mountains and Lika region (SW Croatia). In PDF, Bulletin of Geosciences 90: 721-742.

M. Coiro et al. (2024): Parallel evolution of angiosperm-like venation in Peltaspermales: a reinvestigation of Furcula. Open access, New Phytologist, doi: 10.1111/nph.19726.
"... Although a hierarchical-reticulate venation also occurs in some groups of extinct seed plants, it is unclear whether these are stem relatives of angiosperms
[...] We further suggest that the evolution of hierarchical venation systems in the early Permian, the Late Triassic, and the Early Cretaceous represent ‘natural experiments’ that might help resolve the selective pressures enabling this trait to evolve ..."

José Alejandro D´angelo (2006): Analysis by Fourier transform infrared spectroscopy of Johnstonia (Corystospermales, Corystospermaceae) cuticles and compressions from the Triassic of Cacheuta, Mendoza, Argentina. Ameghiniana, 43.

! W.A. DiMichele et al. (2006): Paleoecology of Late Paleozoic pteridosperms from tropical Euramerica. In PDF, The Journal of the Torrey Botanical Society, 133: 83-118. See also here.

W.A. DiMichele et al. (2005): THE PERMIAN PELTASPERM RADIATION: EVIDENCE FROM THE SOUTHWESTERN UNITED STATES. PDF file, p. 67-79, In: Lucas, S.G. and Zeigler, K.E., (eds.): The Nonmarine Permian, New Mexico Museum of Natural History and Science Bulletin No. 30.
See also here.

! A.B. Doweld (2012): Proposals to conserve the name Scytophyllum Bornem. (fossil Pteridospermae, Peltaspermopsida) against Scytophyllum Eckl. & Zeyh. (Celastraceae) and the name S. bergeri with a conserved type. In PDF, Taxon, 61: 1128-1129.

! A. Elgorriaga et al. (2019): Relictual Lepidopteris (Peltaspermales) from the Early Jurassic Cañadón Asfalto Formation, Patagonia, Argentina. Abstract, Int. J. Plant Sci., 180. See also here (in PDF), and there.
"... and its youngest species, Lepidopteris ottonis, has been used as a Rhaetian marker for several European, Greenlandic, and American localities ..."
"... Lepidopteris scassoi represents the youngest occurrence of the genus by more than 20 Myr. Lepidopteris and Dicroidium lineages, dominant in Southern Hemisphere Triassic ecosystems, show a similar overall pattern of origination (Late Permian), diversification (late Early-Middle Triassic), and decline (Late Triassic), with relict occurrences during the Early Jurassic. ..."

A. Elgorriaga et al. (2019): Southern Hemisphere Caytoniales: vegetative and reproductive remains from the Lonco Trapial Formation (Lower Jurassic), Patagonia. Open access, Journal of Systematic Palaeontology, DOI: 10.1080/14772019.2018.1535456

A. Hamad et al. (2008): A Late Permian flora with Dicroidium from the Dead Sea region, Jordan. In PDF, Review of Palaeobotany & Palynology 149: 85-130.

! T.M. Harris (1933): A new member of the Caytoniales. New Phytologist, 32: 97–114. In PDF, See also here (abstract).

X. He et al. (2017): Peltaspermalean seed ferns with preserved cuticle from the Upper Triassic Karamay Formation in the Junggar Basin, northwestern China. Abstract, Review of Palaeobotany and Palynology, 247: 68-82. See also here (in PDF).

Monte Hieb and Harrison Hieb, Plant Fossils of West Virginia: Ferns and Seed Ferns. Fossil Plants of the Middle Pennsylvanian Period.

! J. Hilton and R.M. Bateman (2006): Pteridosperms are the backbone of seed-plant phylogeny. In PDF, Journal of the Torrey Botanical Society, 133: 119-168.
See also here.

E.V. Karasev (2009): A New Genus Navipelta (Peltaspermales, Pteridospermae) from the Permian/Triassic Boundary Deposits of the Moscow Syneclise. PDF file, Paleontological Journal, 43: 1262-1271.

H. Kerp et al. (2006): Typical Triassic Gondwanan floral elements in the Upper Permian of the paleotropics. In PDF.

Hans Kerp, Abdallah Abu Hamad, Klaus Bandel & Birgit Niemann: A new Upper Permian flora from the Middle East with typical Triassic Gondwana elements. Abstract, The 15th Plant Taphonomy Meeting, Naturalis, National Museum of Natural History, Leiden, The Netherlands, 12-13th November 2004. Provided by the Internet Archive´s Wayback Machine.

! S.D. Klavins et al. (2002): Anatomy of Umkomasia (Corystospermales) from the Triassic of Antarctica. Free access, American Journal of Botany, 89: 664-676.

A.A. Klymiuk et al. (2022): A novel cupulate seed plant, Xadzigacalix quatsinoensis gen. et sp. nov., provides new insight into the Mesozoic radiation of gymnosperms. In PDF, American Journal of Botany. See also here.
Note figure 30: Cupulate Mesozoic gymnosperms.

M. Krings et al. (2006): Frond architecture of Odontopteris brardii (Pteridospermopsida, ?Medullosales): new evidence from the Upper Pennsylvanian of Missouri, U.S.A. Journal of the Torrey Botanical Society, 133: 33-45.
See also here.

! E. Kustatscher and J.H.A. van Konijnenburg-van Cittert (2013): Seed ferns from the European Triassic - an overview. In PDF, In: Tanner, L.H., Spielmann, J.A. and Lucas, S.G., (eds.): The Triassic System. New Mexico Museum of Natural History and Science, Bulletin 61.

E. Kustatscher et al. (2011): Scytophyllum waehneri (Stur) nov. comb., the correct name for Scytophyllum persicum (Schenk) Kilpper, 1975. In PDF, Zitteliana, A 51.

! F. Löcse et al. (2021): Paläobotanische Kostbarkeiten aus den Versteinerten Wäldern von Nová Paka (Tschechien) und Chemnitz (Deutschland)&xnbsp;– Originale zu Stenzel (1889, 1906) und Rudolph (1906) in der paläobotanischen Sammlung der Geologischen Bundesanstalt in Wien. PDF file, in German. Jb. Geol. B.-A., 159: 289–313. See also here.
About old findings of Psaronius tree ferns and Medullosa seed ferns: Ankyropteris brongniartii, Asterochlaena laxa, Asterochlaena ramosa.

! L. Luthardt et al. (2021): Medullosan seed ferns of seasonally-dry habitats: old and new perspectives on enigmatic elements of Late Pennsylvanian–early Permian intramontane basinal vegetation. In PDF, Review of Palaeobotany and Palynology, 288.
See also here.
Note figure 1: Stratigraphy and fossil record of the Medullosales in the context of palaeogeographic and palaeoclimatic developments in the late Paleozoic.
Figure 2: Transverse sections of stem taxa of medullosans with information on their stratigraphy, (palaeo-) geographic origin, taphonomy and palaeo-environment.
Also of interest in this context:
Pflanzliche Botschaften aus der Urzeit (by Tamara Worzewski, November 08, 2022, Spektrum.de, in German).

L. Mander and H.T.P. Williams (2024): The robustness of some Carboniferous fossil leaf venation networks to simulated damage. Open access, R. Soc. Open Sci. 11: 240086. https://doi.org/10.1098/rsos.240086.
"... We attacked fossil venation networks with simulated damage to individual vein segments and leaf blades. For both types of attack, branched venation networks are the least robust to damage, with greater robustness shown by the net-like reticulate networks
[...] A living angiosperm Betula alba was the most robust in our analysis ..."

! S. McLoughlin (2021): Gymnosperms: History of Life: Plants: Gymnosperms. PDF file, in: Elias, S. and Alderton, D. (eds): Encyclopedia of Geology. See also here.

C. Mays and S. McLoughlin (2019): Caught between mass extinctions - the rise and fall of Dicroidium. In PDF.

! S. McLoughlin and R. Prevec (2021): The reproductive biology of glossopterid gymnosperms—A review. Free access, Review of Palaeobotany and Palynology, 295. See also here (in PDF).
! Note fig. 2: Diagramatic reconstructions of glossopterid pollen-bearing organs.

S. McLoughlin et al. (2018): Pachytestopsis tayloriorum gen. et sp. nov., an anatomically preserved glossopterid seed from the Lopingian of Queensland, Australia. Chapter 9, in PDF, in: M. Krings, C.J. Harper, N.R. Cuneo and G.W. Rothwell (eds.): Transformative Paleobotany Papers to Commemorate the Life and Legacy of Thomas N. Taylor.

S. McLoughlin (2017): Antarctica’s Glossopteris forests. In PDF, In: 52 More Things You Should Know About Palaeontology,eds. A. Cullum, A.W. Martinius. Nova Scotia: Agile Libre, p. 22-23. See also here.

S. McLoughlin (2011): Glossopteris - insights into the architecture and relationships of an iconic Permian Gondwanan plant. In PDF, J. Botan. Soc. Bengal 65: 1-14.

S. McLoughlin et al. (2008): Seed ferns survived the end-Cretaceous mass extinction in Tasmania. Open access, American Journal of Botany, 95: 465-471.

B. Meyer-Berthaud et al. (1993): Petrified Stems Bearing Dicroidium Leaves from the Triassic of Antarctica. Palaeontology, 36.

John M. Miller (gigantopteroid.org), University of California, Berkeley: Origin of Angiosperms. See also here or navigate from essay contents.
These expired links are now available through the Internet Archive´s Wayback Machine.

V. Mosbrugger, Institut für Geologie und Paläontologie, Eberhard-Karls-Universität Tübingen: Lecture notes about plant palaeobiology. PDF files, in German. Go to:
Introduction, Progymnosperms.
Provided by the Internet Archive´s Wayback Machine.

! Palaeobotanical Research Group, Münster, Westfälische Wilhelms University, Münster, Germany. History of Palaeozoic Forests, PTERIDOSPERMS OR SEED FERNS. Link list page with rankings and brief explanations. Images of Lyginopteris, Lagenostoma, Sphenopteris crepinii, Lagenostoma lomaxii, Pachytesta, Trigonocarpus, Bernaultia, Schopfipollenites, Bernaultia formosa, Whittleseya microphylla, Medullosa noei, Myeloxyleon, Neuropteris, Alethopteris, Sphenopteris, Alethopteris decurrens, Alethopteris lonchitica, Alethopteris sullivantii, Neuropteris obliqua, Eusphenopteris, Mariopteris, Mariopteris muricata, Reticulopteris, Cyclopteris, Lescuropteris genuina, Alethopteris zeilleri.
Still available via Internet Archive Wayback Machine.

! Palaeobotanical Research Group, Münster, Westfälische Wilhelms University, Münster, Germany. History of Palaeozoic Forests, CALLIPTERIDS. Link list page with rankings and brief explanations. Images of Autunia conferta, Rhachiphyllum schenkii.
This expired link is available through the Internet Archive´s Wayback Machine.

Dennis C. Murphy, ("Devonian Times", a paleontology web site featuring Red Hill): Who's Who at Red Hill, Early Seed Plants (lyginopterids).

S.V. Naugolnykh (2012): A new Carboniferous pteridosperm of Angaraland: Angaranthus victorii Naugolnykh, gen. et spec. nov.(Angaranthaceae, fam. nov., Callistophytales). In PDF, Wulfenia. See also here.
Note figure 9: Reconstructions of Gondwanotheca sibirica reproductive organs.

S.V. Naugolnykh (2012): Vetlugospermum and Vetlugospermaceae: A new genus and family of peltasperms from the Lower Triassic of Moscow syneclise (Russia). In PDF, Geobios, 45: 451–462.
! Note fig. 4 and 7: The phyto-taphonomical pathway of Vetlugospermum rombicum. Explanatory line drawings.

H. Nishida, K.B. Pigg and J. F. Rigby, Swimming sperm in an extinct Gondwanan plant. Glossopteris´ simple mode of reproduction. PDF file, Nature, 422: 396-397; 2003. G.A. Pattemore (2016): The structure of umkomasiacean fructifications from the Triassic of Queensland. In PDF, Acta Palaeobotanica, 56: 17–40.

G.A. Pattemore et al. (2015): Triassic-Jurassic pteridosperms of Australasia: speciation, diversity and decline. In PDF, Boletín Geológico y Minero, 126: 689-722.

G.A. Pattemore et al. (2015): The Mesozoic megafossil genus Linguifolium Arber 1917. In PDF, Acta Palaeobotanica, 55: 123-147.

Kathleen B. Pigg, Department of Plant Biology, Arizona State University:
Plant Fossils and Evolution.
! Go to: Laboratory 11. Paleozoic Seed Ferns, Cordaites & Early Conifers, Gondwana groups.
Websites outdated. Links lead to versions archived by the Internet Archive´s Wayback Machine.

K.P. Pigg and S. McLoughlin (1997): Anatomically preserved Glossopteris leaves from the Bowen and Sydney Basins, Australia. PDF file, Rev. Palaeobot. Palynol. 97: 339-359.

R. Prevec (2011): A structural re-interpretation and revision of the type material of the glossopterid ovuliferous fructification Scutum from South Africa. In PDF, Palaeont. afr., 46: 1–19.
See also here and there (abstract).
Please take notice of the sketch in fig 3 on PDF page 6, showing depressed seed scars of the apical portion of a Scutum leslii fructification.

Rosemary Prevec, Geology Department Rhodes University, South Africa (website by Science in Africa): The power of plants: how ancient forests drive SA´s economy. About Glossopteris forests and coal. This expired link is available through the Internet Archive´s Wayback Machine.

R. Prevec et al. (2009): Portrait of a Gondwanan ecosystem: A new late Permian fossil locality from KwaZulu-Natal, South Africa. Abstract, Review of Palaeobotany and Palynology, 156: 454-493. See also here (PDF file). About Glossopteris.

G.J. Retallack (2002): Lepidopteris callipteroides, an earliest Triassic seed fern of the Sydney Basin, southeastern Australia. In PDF, Alcheringa, Alcheringa 26:475–500.

! G.J. Retallack and D.L. Dilcher (1988): Reconstructions of Selected Seed Ferns. In PDF, Annals of the Missouri Botanical Garden. 75: 1010–1057. See also here.
! Note fig. 1: Reconstructions of Stamnostoma huttense.
! Note fig. 3: Reconstructions of Lyrasperma scotia.
! Note fig. 4: Reconstructions of Calathospermum fimbriatum.
! Note fig. 5: Reconstructions of Lagenostoma lomaxii.
! Note fig. 6: Reconstructions of Pachytesta illionensis.
! Note fig. 7: Reconstructions of Callospermanion pusillum.
! Note fig. 8: Reconstructions of Dictyopteridium sporiferum.
! Note fig. 9: Reconstructions of Peltaspermum thomasii, Triassic.
! Note fig. 10: Reconstructions of Umkomasia cranulata, Triassic.
! Note fig. 11: Reconstructions of Caytonia nathorstii.
Excellent!

G. Shi et al. (2022): Silicified cupulate seed-bearing structures from the Early Cretaceous of eastern Inner Mongolia, China: rethinking the corystosperm concept. Abstract, Journal of Systematic Palaeontology, 20.
"... together with information on other corystosperm ovulate organs from the Northern Hemisphere, significantly expands our understanding of this key group of extinct plants, suggests that the cupules of the Early Cretaceous and Triassic corystosperms are homologous, and raises critical questions about the definition and phylogenetic circumscription of the corystosperms ..."

G. Shi et al. (2021): Mesozoic cupules and the origin of the angiosperm second integument. Abstract, Nature, 594: 223–226. See also here (in PDF).

G. Shi et al. (2019): Diversity and homologies of corystosperm seed-bearing structures from the Early Cretaceous of Mongolia. Abstract, See also here (in PDF).
Note figure 12: Reconstruction of a shoot of Umkomasia mongolica.
Note figure 13: Reconstructions of the seed-bearing units of Umkomasia mongolica, Umkomasia corniculata and Umkomasia trilobata.

! G. Shi et al. (2016): Early Cretaceous Umkomasia from Mongolia: implications for homology of corystosperm cupules. In PDF, New Phytologist, 210: 1418–1429. See also here.

M. Slodownik et al. (2023): Chasing a ghost through Gondwana's history–the fossil record of the 'seed fern' Komlopteris. Open access, Australasian Systematic Botany Society Newsletter, 196: 9-12.
Note figure 2: Geochronological scale indicating the range of Southern Hemisphere Komlopteris species.
"Pteridosperms, also known as 'seed ferns', represent an extinct polyphyletic group of plants with fern like fronds. Unlike true ferns, which reproduce with spores, pteridosperms reproduce with seeds. They were particularly common in the Paleozoic and Mesozoic, but declined noticeably with the diversification of angiosperms
[...] we noticed striking macromorphological similarities with the umkomasialean (or ‘corystospermalean') leaf taxa Kurtziana and Dicroidium which were common in the Triassic ..."

! M. Slodownik et al. (2023): Komlopteris: A persistent lineage of post-Triassic corystosperms in Gondwana. Free access, Review of Palaeobotany and Palynology, 317.
Note figure 1A: Geochronological scale indicating the range of Southern Hemisphere Komlopteris species.
"... Komlopteris is a genus that includes the youngest representative of the so-called ‘seed ferns’
[...] we review the representatives of Komlopteris from Gondwana, emend the genus, establish three new species, and propose five new combinations based on macro-morphological traits ..."

M. Slodownik et al. (2021): Fossil seed fern Lepidopteris ottonis from Sweden records increasing CO₂ concentration during the end-Triassic extinction event. Open access, Palaeogeography, Palaeoclimatology, Palaeoecology, 564. See also here (in PDF).

D. Soltis et al. (2017): Phylogeny and Evolution of the Angiosperms. Book announcement. See also here (Google books). Worth checking out:
! Relationships of Angiosperms to Other Seed Plants. In PDF.
Note figure 1.12: Reconstructions of Caytoniales.
Note figure 1.13: Reconstruction of Bennettitales.
Note figure 1.14: Reconstructions of Pentoxylon plants.
Note figure 1.15: Reconstructions of glossopterids.

A.K. Srivastava and R. Srivastava (2016): Glossopteridales: An intricate group of plants. In PDF, The Palaeobotanist, 65: 159–167.

A.K. Srivastava et al. (2010): Dicroidium: no more a Triassic Gondwana index fossil. PDF file.

Hans Steur, Ellecom, The Netherlands: Hans´ Paleobotany Pages. Plant life in the Silurian, Devonian, Carboniferous, Permian and Cretaceous. Go to: Seed ferns from the Piesberg and Ibbenbüren. See also: The Permian flora of Lodève (France), The seed ferns.

! G.W. Stull et al. (2012): Palaeoecology of Macroneuropteris scheuchzeri, and its implications for resolving the paradox of "xeromorphic" plants in Pennsylvanian wetlands. In PDF, Palaeogeography, Palaeoclimatology, Palaeoecology, 331-332: 162-176.
See also here.

Ralph E. Taggart, Department of Botany and Plant Pathology/Department of Geological Sciences at Michigan State University, East Lansing:
! BOT335 Lecture Schedule. Some interesting chapters in terms of palaeobotany, e.g.
The First Vascular Land Plants;
Carboniferous Forests;
Arborescent Lycopods;
Psaronius: a Carboniferous tree-fern;
Carboniferous Horsetails;
Carboniferous Seed Ferns;
The Evolution of Conifers;
Cycadophytes, the True Cycads;
Mesozoic Cycadeoids;
Ginkgophytes;
North American Redwoods, Past and Present.
These expired links are available through the Internet Archive´s Wayback Machine.

! E.L. Taylor and T.N. Taylor (2009): Seed ferns from the late Paleozoic and Mesozoic: Any angiosperm ancestors lurking there? Open access, American Journal of Botany, 96: 237-251.
! "... In our opinion, it will be more productive to attempt to solve Darwin’s mystery if there were greater attention directed at mining the rock record in the hope of discovering more informative and new specimens, than to continue to construct new phylogenies using the same, often ambiguous characters. ..."
Worth checking out: Glossopterid vegetative and reproductive organs:
Note fig. 2: Suggested reconstruction of Ottokaria zeilleri.
Fig. 10: Suggested reconstruction of a Glossopteris megasporophyll with seeds attached to adaxial surface.
12: Diagrammatic reconstruction of Denkania indica.
Reproductive organs of Caytoniales and Corystospermales:
15. Suggested reconstruction of Caytonia cupule showing attachment of seeds and “stigmatic lip”.
16. Reconstruction of Caytonanthus arberi.
19. Suggested reconstruction of Umkomasia asiatica.
21. Diagrammatic reconstruction of Umkomasia uniramia.
Reproductive organs of Corystosperms and Petriellales:
25. Suggested reconstruction of Pilophorosperma geminatum.
28. Suggested reconstruction of Pteruchus fremouwensis.
30. Suggested reconstruction of Petriellaea triangulata.
32. Diagrammatic cutaway of Petriellaea triangulata cupule.
Reproductive organs of peltasperms:
34. Suggested reconstruction of Autunia conferta ovuliferous organ.
36. Suggested reconstruction of two Autunia conferta megasporophylls.
37. Suggested reconstruction of Peltaspermum rotula megasporophyll showing several ovules.
39. Suggested reconstruction of Peltaspermum thomasii axis bearing numerous megasporophylls.
40. Suggested reconstruction of Peltaspermopsis polyspermis.
41. Suggested reconstruction of Lepidopteris frond with pollen organs of the Antevsia-type at the tip.
42. Suggested reconstruction of Antevsia zeilleri pollen organ showing pinnate axis bearing clusters of pollen sacs.

E.L. Taylor et al. (2006): Mesozoic seed ferns: Old paradigms, new discoveries. PDF file, Journal of the Torrey Botanical Society, 133: 62-82.
See also here.

E.L. Taylor (1996): Enigmatic gymnosperms? Structurally preserved Permian and Triassic seed ferns from Antarctica. PDF file, Review of Palaeobotany and Palynology.
Still available through the Internet Archive´s Wayback Machine.
See also here (abstract).

R. Tewari et al. (2017): The Glossopteris flora of Manuguru Area, Godavari Graben, Telangana, India. In PDF, Palaeobotanist, 66: 17–36.

! H.H. Thomas(1933): On some pteridospermous plants from the Mesozoic rocks of South Africa. Open access, Philosophical Transactions of the Royal Society, B. 222: 193–265.

! J.A. Townrow (1966): The Peltaspermaceae, a pteridosperm family of Permian and Triassic age. PDF file, Palaeontology, 3: 333–361.
Website outdated, download a version archived by the Internet Archive´s Wayback Machine.

J. Unverfärth et al. (2022): Mummified Dicroidium (Umkomasiales) leaves and reproductive organs from the Upper Triassic of South Australia. In PDF, Palaeontographica, B, 304: 49-225. See also here.
Note figure 4: Schematic key to the Dicroidium GOTHAN 1912 taxa.

V. Vajda et al. (2024): Confirmation that Antevsia zeilleri microsporangiate organs associated with latest Triassic Lepidopteris ottonis (Peltaspermales) leaves produced Cycadopites-Monosulcites-Chasmatosporites- and Ricciisporites-type monosulcate pollen. Abstract, Palaeogeography, Palaeoclimatology, Palaeoecology, 640.

! V. Vajda et al. (2023): The ‘seed-fern’ Lepidopteris mass-produced the abnormal pollen Ricciisporites during the end-Triassic biotic crisis. Free access, Palaeogeography, Palaeoclimatology, Palaeoecology, 627.
Note figure 4: Microsporophyll Antevsia zeilleri and microsporangia (pollen sacs) with contained pollen linked to the Lepidopteris ottonis plant.
! Figure 10C: Reconstruction of branch of male plant with short shoots bearing Lepidopteris ottonis foliage and Antevsia zeilleri microsporophylls.
"... We show that R. tuberculatus is a large, abnormal form of the small smooth-walled monosulcate pollen traditionally associated with L. ottonis, which disappeared at the ETE [end-Triassic mass extinction], when volcanism induced cold-spells followed by global warming. We argue that the production of aberrant R. tuberculatus resulted from ecological pressure in stressed environments that favoured asexual reproduction in peltasperms ..."

M. Wan et al. (2016): A typical Euramerican floral element from the Shanxi Formation (Cisuralian, lower Permian) in the Wuda Coal Field, Inner Mongolia, North China. Palaeobiodiversity and Palaeoenvironments, 96: 507–515.
Provided by the Internet Archive´s Wayback Machine.
See also here.

J. Wang et al. (2003): Discovery of organic connection of Chiropteris Kurr and Nystroemia Halle from Early Permian of western Henan, China. Abstract, Chinese Science Bulletin, 48: 2248-2252.

K.Y. Wang et al. (2022): Anatomically preserved cordaitalean trees from the Pennsylvanian of Yangquan City, Shanxi Province, and their implication for a perhumid climate in North China Block. In PDF, Palaeoworld, 31: 294-310.
See also here.

Wikipedia, the free encyclopedia:
Petriellales (in German).

Wikipedia, the free encyclopedia:
! Pteridospermatophyta.
Samenfarne (in German).
! Caytoniales.
Caytoniales (in German).

Y. Xu et al. (2023): How similar are the venation and cuticular characters of Glossopteris, Sagenopteris and Anthrophyopsis? In PDF, Review of Palaeobotany and Palynology, 316.
See likewise here.
Note figure 1: Geologic ranges of some representative reticulate taxa.
"... Considering the putatively close relationship of glossopterids (Glossopteris), Caytoniales (Sagenopteris) and Bennettitales (here encompassing Anthrophyopsis) resolved as members of the ‘glossophyte’ clade in some past phylogenetic studies, cuticular features suggest that these groups are not closely related. In addition, anastomosing venation, superficially similar to that of Glossopteris, Sagenopteris and Anthrophyopsis appears to have arisen independently in numerous other plant groups ..."

N. Zavialova (2024): Comment on “The ‘seed-fern’ Lepidopteris mass-produced the abnormal pollen Ricciisporites during the end-Triassic biotic crisis” by V. Vajda, S. McLoughlin, S. M. Slater, O. Gustafsson, and A. G. Rasmusson [Palaeogeography, Palaeoclimatology, Palaeoecology, 627 (2023), 111,723]. Abstract, Review of Palaeobotany and Palynology, 322.
"... Recently, Ricciisporites Lundblad and Cycadopites Wodehouse (= Monosulcites Cookson) pollen types have been found cooccurring in Antevsia zeilleri
[...] the two pollen types are too dissimilar by their exine ultrastructure as well as by the general morphology and exine sculpture.
[...] Another explanation should be found for the presence of Ricciisporites tetrads in these pollen sacs ..."

N. Zavialova and J.H.A. van Konijnenburg-van Cittert (2011): Exine ultrastructure of in situ peltasperm pollen from the Rhaetian of Germany and its implications. In PDF, Review of Palaeobotany and Palynology, 168: 7-20.
See also here.