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Crossotheca

Extinct genus of seed ferns From Wikipedia, the free encyclopedia

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]

Quick facts Scientific classification, Species ...
Crossotheca
Temporal range: Carboniferous-Triassic,
318.1–235.0 Ma
Specimen P 30369 (left) and the pollen bearing organs of C. hughesiana from Dudley, England
Reconstruction of C. höninghausi
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Division: †Pteridospermatophyta
Class: †Lyginopteridopsida
Order: †Lyginopteridales
Genus: †Crossotheca
Zeiller (1883)[1]
Species
  • †C. boulayi Zeiller (1883)[1]
  • †C. communis Lesquererfx
  • †C. crepini Zeiller (1883)
  • †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
  • †C. reniformis
  • †C. trichomanoides
  • †C. trisecta Sellards
Synonyms
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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).

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