Ptisana purpurascens

Ptisana purpurascens
Conservation status
Near Threatened (IUCN 3.1)
Scientific classification
Kingdom:	Plantae
Division:	Pteridophyta
Class:	Marattiopsida
Order:	Marattiales
Family:	Marattiaceae
Genus:	Ptisana
Species:	P. purpurascens (de Vries) Murdock]
Binomial name
Ptisana purpurascens

Ptisana purpurascens is a large fern belonging to the botanical family Marattiaceae. It has a globular rhizome with stipule-like fleshy outgrowths. The leaves are dark green, twice pinnate and up to 1 metre long. Every pinnule has up to six pairs of leaflets. The petioles are dark-purplish, hence the name 'purpurascens' meaning 'becoming purple'. The sporangia are fused in all Ptisana into a bivalvate synangium.

Conservation plans have been proposed for Ptisana purpurascens, an endemic of the distant Ascension Island in the South Atlantic, where a single population remains on Green Mountain. This population is now believed to be more stable than previously feared, but long-term threats to its survival do exist, in the form of competition with alien invasive species like introduced plants such as Lantana camara and grazing by sheep.

See also

• Ptisana salicina, a related plant from New Zealand.
• Danaea kalevala, a related plant from the Caribbean.

References

• Gray, A., Palembe, T., Stroud, S. 2005. The conservation of the endemic vascular flora of Ascension Island and threats from alien species. Oryx 39: 449-453. [1]
• See the ARKive site for additional information [2]