Salix

by | Mar 13, 2018 | Salix

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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]

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. ^ a b c Zeiller, R. (1883). Fruitifications de Fougèred du Terrain Houiller. Ann. Sci. Nat. 6e sèr. Bot. XVI, pp. 177-209
  2. ^ a b c 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. ^ a b c "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. ^ a b c d Andrews, N. H. (1970). Index of Generic Names of Fossil Plants, 1820-1965. Geological Survey Bulletin 1-354
  9. ^ a b Jud, N. A. (2011). Unpublished taxonomic opinions.


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