Pteridospermatophyta

Taxobox
name = Pteridospermatophyta
fossil_range = Devonian-Eocene


image_width = 250px
image_caption =
domain = Eukaryota
unranked_regnum = Archaeplastida
regnum = Plantae
divisio = †Pteridospermatophyta
subdivision_ranks = Orders
subdivision =
* Arberiales
* Calamopityales
* Callistophytales
* Corystospermales
* Gigantonomiales
* Glossopteridales
* Leptostrobales
* Peltaspermales

Pteridospermatophyta, also called seed ferns, is an extinct spermatophyte group of the Plantae kingdom. Members of this division were predominant at the late Devonian, declined some ma|250, and mostly disappeared by the Cretaceous, though fossil evidence indicates that they survived into the Eocene in Tasmania.McLoughlin, S., R.J. Carpenter, G.J. Jordan, & R.S. Hill. (2008). "Seed ferns survived the end-Cretaceous mass extinction in Tasmania." "American Journal of Botany," 95: 465-471.] The Pteridospermatophyta have not yet acquired a clear position in botanical systematics and indeed appear to be a paraphyletic form taxon. Some appear to be allied or ancestral to the gymnosperms, others seem to be closer to angiosperms.

The seeds of seed ferns develop differently from the other seed plants, as they are believed to grow inside a cupule.

Orders often united in the seed ferns are:
* Arberiales
* Calamopityales
* Callistophytales
* Corystospermales
* Gigantopteridales (= "Gigantonomiales")
* Glossopteridales
* Leptostrobales
* Peltaspermales

References

External links

* [http://taggart.glg.msu.edu/bot335/sfern.htm Seed fern paleontology]
* [http://www.uni-muenster.de/GeoPalaeontologie/Palaeo/Palbot/seite9.html Seed ferns]