Pterostylis pyramidalis

Pterostylis pyramidalis
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Monocots
Order:	Asparagales
Family:	Orchidaceae
Subfamily:	Orchidoideae
Tribe:	Diurideae
Subtribe:	Pterostylidinae
Genus:	Pterostylis
Species:	P. pyramidalis
Binomial name
Pterostylis pyramidalis Lindl.

Pterostylis pyramidalis, commonly known as the Tall snail orchid or Leafy snail orchid is a species of orchid which is endemic to the south–west of Western Australia. As suggested by one of its common names, it can be distinguished from other snail orchids by its height (up to 35 cm).

Description

P. pterostylis has 3 or 4 leaves bunched near the base and 6 or 7 scattered up the flower stalk, with those near the base having a petiole (stalk) and those further up sessile (stalkless). The leaves are 8–23 mm long and 8–12 mm wide. The flower stem is 100–350 mm tall and smooth. The flowers appear from August to October and are green and white, 16–20 mm x 6–8 mm. Flowering is stimulated by summer fires.^[1]

Distribution and habitat

The Tall snail orchid grows on grey-black peaty sand on the margins of swamps. It sometimes forms large colonies often with the flowers partly submerged. It occurs in the Avon Wheatbelt, Esperance Plains, Jarrah Forest, Mallee, Swan Coastal Plain and Warren biogeographic regions of Western Australia.^[2]

Taxonomy and naming

P. pyramidalis was first described by John Lindley in A Sketch of the Vegetation of the Swan River Colony (Appendix liii) in 1840.^[3] The genus Pterostylis has been reviewed by Jones et al. and P. pyramidalis has been renamed Linguella pyramidalis (Lindl.) D.L.Jones & M.A.Clem.^[4][5] The specific epithet (pyramidalis) is the Latin word meaning pyramid-shaped or tetragonal.^[6]

Conservation status

This species is classified as Not Threatened.^[2]

References