Crossotheca | |
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Specimen P 30369 (left) and the pollen bearing organs of C. hughesiana from Dudley, England | |
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Reconstruction of C. höninghausi | |
Scientific classification ![]() | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Division: | †Pteridospermatophyta |
Class: | †Lyginopteridopsida |
Order: | †Lyginopteridales |
Genus: | †Crossotheca Zeiller (1883)[1] |
Species | |
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Synonyms | |
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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
[edit]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
[edit]- ^ a b c Zeiller, R. (1883). Fruitifications de Fougèred du Terrain Houiller. Ann. Sci. Nat. 6e sèr. Bot. XVI, pp. 177-209
- ^ 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.
- ^ Potonie, R. (1954). Position of the Paleozoic spore genera in the natural system.
- ^ F. L. S., Johnson, T. D. (1911). A seed-bearing Irish Pteridosperm, Crossotheca Höninghausi, Kidston (Lyginodendron oldhamium, Williamson). Royal Dublin Society
- ^ a b c "Palaeobotany," Encyclopædia Britannica (11th ed.), v. 21, 1911, p. 536, fig. 28.
- ^ 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.
- ^ 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.
- ^ a b c d Andrews, N. H. (1970). Index of Generic Names of Fossil Plants, 1820-1965. Geological Survey Bulletin 1-354
- ^ a b Jud, N. A. (2011). Unpublished taxonomic opinions.
Well, that’s interesting to know that Psilotum nudum are known as whisk ferns. Psilotum nudum is the commoner species of the two. While the P. flaccidum is a rare species and is found in the tropical islands. Both the species are usually epiphytic in habit and grow upon tree ferns. These species may also be terrestrial and grow in humus or in the crevices of the rocks.
View the detailed Guide of Psilotum nudum: Detailed Study Of Psilotum Nudum (Whisk Fern), Classification, Anatomy, Reproduction