The
fern genus ''Todea'' is known from only two living species. Species in the genus ''Todea'', as ''
Leptopteris'', are distinct from other in
Osmundaceae in that
sporangia are born on laminar pinnules.
Description
The species in the genus have a sub-erect stem and coarse,
pinnate leaves. Many large sporangia are located on the bottoms of the leaves and are not arranged in sori or covered by an
indusium
A sorus (pl. sori) is a cluster of sporangia (structures producing and containing spores) in ferns and fungi. A coenosorus (plural coenosori) is a compound sorus composed of multiple, fused sori.
Etymology
This New Latin word is from Ancient ...
.
Species
Only two extant species are currently recognised. ''
Todea barbara
''Todea barbara'' is known as the king fern. Occurring in moist areas of south eastern Australia, and also indigenous to New Zealand and South Africa.
Taxonomy
Carl Linnaeus described the king fern in volume II of his '' Species Plantarum'' as ...
'' L., known as the king fern, is native to
South Africa,
New Zealand, and
Australia
Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...
while ''
Todea papuana'' H. is known only from
Papua New Guinea.
So far the fossil record of the genus ''Todea'' consists only of the permineralized rhizome ''
Todea tidwellii'' from the Lower
Cretaceous of
Vancouver Island, Canada and the species ''Todea amissa'', known from the Eocene of
Patagonia,
Argentina.
''Todea minutacaulis'' has also been described from the Lower Cretaceous of Vancouver Island and represents the first anatomically preserved fossil fern sporeling from the fossil record.
References
Bibliography
* Nathan Jud, Gar W.Rothwell and Ruth A. Stockey. 2008. "''Todea'' from the Lower Cretaceous of western North America: implications for the phylogeny, systematics, and evolution of modern Osmundaceae."
American Journal of Botany, 95:330-339.
* E.Hennipman. 1968. A new ''Todea'' from New Guinea, with remarks on the generic delimitation of recent Osmundaceae.
Blumea 16: 105-108
* C.Michael Hogan. 2010
''Fern''. Encyclopedia of Earth. eds. Saikat Basu and C.Cleveland. National Council for Science and the Environment Washington DC.
* Walker, Z., Rothwell, G. W., & Stockey, R. A. 2023
Fossil evidence for sporeling development of a Mesozoic osmundaceous fern ''American Journal of Botany'', 110: e16210-n/a.
https://doi.org/10.1002/ajb2.16210
External links
- ''includes photos'' (author: David Nicholls, January 1998).''
Osmundales
Ferns of Australasia
Fern genera
{{Polypodiidae-stub