Crossotheca

Crossotheca is an extinct genus of seed ferns (Pteridospermatophyta) widespread in coal measures of Carboniferous, Permian and Triassic age,[8] with possible Devonian remains known from Belgium.[8][9] The type species is C. crepini, named and described in 1883 by R. Zeiller,[1] and the genus is known from fossils found in Belgium (?), Canada, China, England, France, Hungary, Ireland, Poland and the United States.[8]

Crossotheca
Temporal range: Carboniferous-Triassic,
Specimen P 30369 (left) and the pollen bearing organs of C. hughesiana from Dudley, England
Reconstruction of C. höninghausi
Scientific classification
Kingdom:
Plantae
Division:
†Pteridospermatophyta
Class:
†Lyginopteridopsida
Order:
†Lyginopteridales
Genus:
†Crossophyta

Zeiller, 1883[1]
Binomial name
†Crossophyta crepini
Zeiller, 1883[1]
Other species
  • †C. boulayi Zeiller, 1883[1]
  • †C. communis Lesquererfx
  • †C. fimbriata Kidston, 1906[2]
  • †C. grievii Potonie, 1954[3]
  • †C. höninghausi Johnson & Kidston, 1911[4][5] [originally Sphenopteris]
  • †C. hughesiana Kidston, 1906[2]
  • †C. kentuekiensis Stubbefield, Taylor & Daghlian, 1982[6]
  • †C. kidstom? (nomen dubium)
  • †C. kidstoni Crookall
  • †C. pinnatifida Gutbier
  • †C. sagittata Lesquererfx
  • †C. schatzlarensis Stur. (Kidston, 1906[2])
  • †C. reniformis (Brongniart)
  • †C. trichomanoides (Sternberg)
  • †C. trisecta Sellards
Synonyms

One species, C. höninghausi, is the male fructification of Lyginodendron oldhami[5][9] and the same species is the microsporangia-bearing member of Lyginopteris.[5]

Description

A fertile Crossotheca branch shows the following features:[2][8]

  • 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
  1. Zeiller, R. (1883). Fruitifications de Fougèred du Terrain Houiller. Ann. Sci. Nat. 6e sèr. Bot. XVI, pp. 177-209
  2. Kidston, Robert (1906). "On the microsporangia of the pteridosperms". The Royal Society Publishing. 77 (515): 161–162. Bibcode:1906RSPSB..77..161K. doi:10.1098/rspb.1906.0005.
  3. Potonie, R. (1954). Position of the Paleozoic spore genera in the natural system.
  4. F. L. S., Johnson, T. D. (1911). A seed-bearing Irish Pteridosperm, Crossotheca Höninghausi, Kidston (Lyginodendron oldhamium, Williamson). Royal Dublin Society
  5. "Palaeobotany," Encyclopædia Britannica (11th ed.), v. 21, 1911, p. 536, fig. 28.
  6. 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.
  7. 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.
  8. Andrews, N. H. (1970). Index of Generic Names of Fossil Plants, 1820-1965. Geological Survey Bulletin 1-354
  9. Jud, N. A. (2011). Unpublished taxonomic opinions.


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