{{Short description|Extinct genus of seed ferns}} {{automatic taxobox | fossil_range = Carboniferous-Triassic, <br>{{fossilrange|318.1|235.0|earliest=388.1}} | image = Crossotheca.jpg | image_caption = Specimen P 30369 (left) and the pollen bearing organs of ''C. hughesiana'' from Dudley, England | image2 = EB1911 Palaeobotany - Crossotheca Höninghausi.jpg | image2_caption = Reconstruction of ''C. höninghausi'' | taxon = Crossotheca | authority = Zeiller (1883)<ref name=Zeiller83>Zeiller, R. (1883). Fruitifications de Fougèred du Terrain Houiller. ''Ann. Sci. Nat. 6e sèr. Bot.'' XVI, pp. 177-209</ref> | subdivision_ranks = Species | subdivision = *{{extinct}}''C. boulayi'' <small>Zeiller (1883)<ref name=Zeiller83 /></small> *{{extinct}}''C. communis'' <small>Lesquererfx</small> *{{extinct}}''C. crepini'' <small>Zeiller (1883)</small> *{{extinct}}''C. fimbriata'' <small>Kidston (1906)<ref name=Kid06 /></small> *{{extinct}}''C. grievii'' <small>Potonie (1954)<ref>Potonie, R. (1954). Position of the Paleozoic spore genera in the natural system.</ref></small> *{{extinct}}''C. höninghausi'' <small>Johnson & Kidston (1911)<ref name=Kidston1911>F. L. S., Johnson, T. D. (1911). A seed-bearing Irish Pteridosperm, ''Crossotheca Höninghausi'', Kidston (''Lyginodendron oldhamium'', Williamson). ''Royal Dublin Society''</ref><ref name=Scott1911 /> [originally ''Sphenopteris'']</small> *{{extinct}}''C. hughesiana'' <small>Kidston (1906)<ref name=Kid06 >{{cite journal|last1=Kidston|first1=Robert |year=1906|title=On the microsporangia of the pteridosperms |journal= Proceedings of the Royal Society of London. Series B, Containing Papers of a Biological Character|volume=77 |issue=515 |pages=161–162 |doi=10.1098/rspb.1906.0005|bibcode=1906RSPSB..77..161K |doi-access= }}</ref></small> *{{extinct}}''C. kentuekiensis'' <small>Stubbefield, Taylor & Daghlian (1982)<ref>Stubblefield, S.P., Taylor, T.N. and Daghlian, C.P., (1982). Compressed plants from the Lower Pennsylvanian of Kentucky (U.S.A.). I. ''Crossotheca kentuekiensis'' n. sp. ''Rev. Palaeobot. Palynol.'', 36: 197--204.</ref></small> *{{extinct}}''C. kidstom''? <small>(''nomen dubium'')</small> *{{extinct}}''C. kidstoni'' <small>Crookall</small> *{{extinct}}''C. pinnatifida'' <small>Gutbier</small> *{{extinct}}''C. sagittata'' <small>Lesquererfx</small> *{{extinct}}''C. schatzlarensis'' *{{extinct}}''C. reniformis'' *{{extinct}}''C. trichomanoides'' *{{extinct}}''C. trisecta'' <small>Sellards</small> | synonyms = *''Sphenopteris höninghausi'' <small>Brongniart (1849)<ref>Brongniart, A.T. (1849). Tableau des genres de végétaux fossiles considérés sous le point de vue de leur classification botanique et de leur distribution géologique. ''Dictionnaire Universel d'Histoire Naturelle.'' 13. 1-127.</ref></small> }} '''''Crossotheca''''' is an extinct genus of seed ferns (Pteridospermatophyta) widespread in coal measures of Carboniferous, Permian and Triassic age,<ref name=Andrews70>Andrews, N. H. (1970). Index of Generic Names of Fossil Plants, 1820-1965. ''Geological Survey Bulletin'' 1-354</ref> with possible Devonian remains known from Belgium.<ref name=Andrews70 /><ref name=Jud11 /> The type species is '''''C. crepini''''', named and described in 1883 by R. Zeiller,<ref name=Zeiller83 /> and the genus is known from fossils found in Belgium (?), Canada, China, England, France, Hungary, Ireland, Poland and the United States.<ref name=Andrews70 />
One species, ''C. höninghausi'', is the male fructification of ''Lyginodendron oldhami''<ref name=Scott1911>"Palaeobotany," ''Encyclopædia Britannica'' (11th ed.), v. 21, 1911, p. 536, fig. 28.</ref><ref name=Jud11>Jud, N. A. (2011). Unpublished taxonomic opinions.</ref> and the same species is the microsporangia-bearing member of ''Lyginopteris''.<ref name=Scott1911 />
==Description== A fertile ''Crossotheca'' branch shows the following features:<ref name=Kid06 /><ref name=Andrews70 />
*The branch tips are slightly expanded into a circular or paddle-shaped limb. *At the tip of each branch there are a few bilocular sporangia attached together. *Each sporangium contains a number of microspores (pollens).
== References == {{reflist}}
{{Taxonbar|from=Q108387589}}
Category:Pteridospermatophyta Category:Carboniferous plants Category:Permian plants Category:Triassic plants Category:Prehistoric plants Category:Prehistoric plant genera Category:Fossil taxa described in 1883
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