Asplenium pumilum, often called the triangle spleenwort or hairy spleenwort, is a species of fern in the spleenwort family, the Aspleniaceae.
Description
With about 800 accepted species of the genus Asplenium, the spleenworts exhibit a bewildering spectrum of physical features. Here are some of the most distinctive for Asplenium pumilum:
Plant on old stone wall
The species is extremely variable in appearance.
The blades are triangular in shape and range from undivided into segments, to twice pinnately divided.
Blades triangular in shape, up to 16 cm (~
Blade divisions, the pinnae, may number 0-5 pairs, are egg-shaped to triangular, and range from having no indentations or teeth to being lobed or even divided into further divisions at their tips.
petioles up to 16 cm (~6+1⁄3 inches) long are 1-2 times the blade's length; they're green on small leaves but on larger ones they are black on the lower surface and green above.
Sori number 1–35 on each pinna; they are long and slender, occur along veins and range from straight to crescent-shaped; during development they are protected by silvery tissue along their sides, the indusium.
Taxonomy
It has been suggested that extreme forms of Asplenium pumilum are so different from one another that two species may be present.
In the genus name Asplenium, the splen- is based on the Greek splen, meaning 'spleen'; Dioscorides thought spleenworts were useful for treating spleen diseases.
The specific epithet, pumilum, is from the Latin pumilus meaning "dwarfish" or "like a dwarf", probably referring to the species' relatively small size.
Studies of maximum likelihood and Bayesian phylogenetic inference suggest that Asplenium pumilum is sister to the neotropical Asplenium (Schaffneria) nigripes, despite considerable morphological differences between them.
Etymology
In the genus name Asplenium, the splen- is based on the Greek splen, meaning 'spleen'; Dioscorides thought spleenworts were useful for treating...
