{{Short description|Extinct class of vascular plants}} {{Paraphyletic group | auto = yes | fossil_range = {{Geological range|Middle Devonian|Lopingian}} | image = Archaeopteris.JPG | image_caption = ''Archaeopteris'' fossil leaves | taxon = Progymnospermopsida | authority = | subdivision_ranks = Orders | subdivision = *†Aneurophytales *†Archaeopteridales *†Noeggerathiales *†Protopityales }}
The '''progymnosperms''' are an extinct group of woody, spore-bearing plants that is presumed to have evolved from the trimerophytes, and eventually gave rise to the spermatophytes, ancestral to both gymnosperms and angiosperms (flowering plants).<ref name=gk>{{cite book| vauthors = Stewart WN, Rothwell GW |title=Paleobiology and the evolution of plants|year=1993|publisher = Cambridge University Press|page=521pp}}</ref> They have been treated formally at the rank of division '''Progymnospermophyta''' or class '''Progymnospermopsida''' (as opposite). The stratigraphically oldest known examples belong to the Middle Devonian order the Aneurophytales, with forms such as ''Protopteridium'', in which the vegetative organs consisted of relatively loose clusters of axes.<ref name="Lang">{{cite journal| vauthors = Lang WH | title = II.—Contributions to the Study of the Old Red Sandstone Flora of Scotland. I. On Plant-Remains from the Fish-Beds of Cromarty. II. On a Sporangium-bearing Branch-System from the Stromness Beds. | journal = Earth and Environmental Science Transactions of the Royal Society of Edinburgh | date = 1926 | volume = 54 | issue = 2 | pages = 253–79 | doi = 10.1017/S0080456800027599 | s2cid = 131163187 }}</ref> ''Tetraxylopteris'' is another example of a genus lacking leaves. In more advanced aneurophytaleans such as ''Aneurophyton'' these vegetative organs started to look rather more like fronds,<ref name="Serlinbanks">{{cite journal | vauthors = Serlin BS, Banks HP | date = 1979 | title = Morphology and anatomy of ''Aneurophyton'', a progymnosperm from the Late Devonian of New York. | journal = Palaeontographica Americana | volume = 8 | pages = 343–359 | doi = }}</ref> and eventually during Late Devonian times the aneurophytaleans are presumed to have given rise to the pteridosperm order, the Lyginopteridales. In Late Devonian times, another group of progymnosperms gave rise to the first really large trees known as ''Archaeopteris''. The latest surviving group of progymnosperms is the Noeggerathiales, which persisted until the end of the Permian.<ref>{{cite journal| vauthors = Wang J, Hilton J, Pfefferkorn HW, Wang S, Zhang Y, Bek J, Pšenička J, Seyfullah LJ, Dilcher D | display-authors = 6 | title = Ancient noeggerathialean reveals the seed plant sister group diversified alongside the primary seed plant radiation | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 118 | issue = 11 | article-number = e2013442118 | date = March 2021 | pmid = 33836571 | pmc = 7980368 | doi = 10.1073/pnas.2013442118 | doi-access = free | bibcode = 2021PNAS..11813442W }}</ref>
Other characteristics: *Vascular cambium with unlimited growth potential is present as well as xylem and phloem. *Ancestors of the earliest seed plants as well as the first true trees. <!--*Superficially conifer/spruce-like in appearance. NOT ALL, REVISE --> *Strong monopodial growth is exhibited. <!--*Macrophylls present as well as simple leaves. NOT ALL, REVISE --> *Aneurophytales was homosporous, while the remaining groups were heterosporous.<ref name="Wood">[https://pmc.ncbi.nlm.nih.gov/articles/PMC7980368/ Ancient noeggerathialean reveals the seed plant sister group diversified alongside the primary seed plant radiation]</ref> *Pycnoxylic wood was found in both Archaeopteridales and Noeggerathiales.<ref name="Wood"/>
==Phylogeny== Progymnosperms are a paraphyletic grade of plants.<ref>{{cite journal| vauthors = Crane PR, Herendeen P, Friis EM | title = Fossils and plant phylogeny | journal = American Journal of Botany | volume = 91 | issue = 10 | pages = 1683–99 | date = October 2004 | pmid = 21652317 | doi = 10.3732/ajb.91.10.1683 | name-list-style = amp | doi-access = free }}</ref><ref>{{cite book | author=Pelletier | year=2012 | title=Empire biota: taxonomy and evolution 2nd ed | page=354 | publisher=Lulu.com| isbn=978-1-329-87400-8 }}</ref><ref>{{cite journal | vauthors = Wang J, Hilton J, Pfefferkorn HW, Wang S, Zhang Y, Bek J, Pšenička J, Seyfullah LJ, Dilcher D | display-authors = 6 | title = Ancient noeggerathialean reveals the seed plant sister group diversified alongside the primary seed plant radiation | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 118 | issue = 11 | article-number = e2013442118 | date = March 2021 | pmid = 33836571 | pmc = 7980368 | doi = 10.1073/pnas.2013442118 | doi-access = free | bibcode = 2021PNAS..11813442W }}</ref>
{{barlabel |size=1 |at=3 |label=Progymnosperms|cladogram= {{clade| style=font-size:100%;line-height:80% |label1=Tracheophyta |1={{Clade |1=†Rhyniopsida |2={{Clade |1=Lycopodiophytina (Clubmosses, Spikemosses & Quillworts) |2={{Clade |1=†''Eophyllophyton'' |2={{Clade |1=†Trimerophytopsida |2={{Clade |label1=Moniliformopses |1=Polypodiophytina (Ferns) |label2=Radiatopses |2={{Cladex |1=†''Pertica'' |label2=Lignophytes |2={{Cladex |barbegin1=darkgreen |1=†Aneurophytopsida |label2=Metalignophytes |2={{Cladex |1={{Cladex |1=†Protopityales <small>Nemejc 1963</small> |2={{Cladex |1=†Archaeopteridales |2=†Noeggerathiales <small>Nemejc emend. J. Wang ''et al''. 2021</small> }} }}|barend1=darkgreen |2=Spermatophytina (Seed plants) }} }} }} }} }} }} }} }} }} }}
== References == {{Reflist}}
== External links == *[http://comenius.susqu.edu/biol/202/ARCHAEPLASTIDA/VIRIDIPLANTAE/Vascular%20Cryptogams/PROGYMNOSPERMOPHYTA/default.htm Progymnospermophyta] {{Webarchive|url=https://web.archive.org/web/20150402154657/http://comenius.susqu.edu/biol/202/archaeplastida/viridiplantae/vascular%20cryptogams/progymnospermophyta/default.htm |date=2015-04-02 }} *[https://books.google.com/books?id=0DfYJsVRmUcC&dq=Progymnospermophyta&pg=PA723 Botany: an introduction to plant biology]
{{Plant classification}} {{Taxonbar|from1=Q2032825|from2=Q18657593}}
Category:Middle Devonian first appearances Category:Middle Devonian plants Category:Mississippian plants Category:Mississippian extinctions Category:Late Devonian plants Category:Paraphyletic groups Category:Prehistoric plant taxa
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