Pterostylis sargentii

Frog greenhood
File:Pterostylis sargentii - Flickr 003 (1).jpg
Pterostylis sargentii between Williams and Narrogin
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Monocots
Order:	Asparagales
Family:	Orchidaceae
Subfamily:	Orchidoideae
Tribe:	Diurideae
Subtribe:	Pterostylidinae
Genus:	Pterostylis
Species:	P. sargentii
Binomial name
Pterostylis sargentii C.R.P.Andrews
Synonyms
Oligochaetochilus sargentii (C.R.P.Andrews) Szlach. Ranorchis sargentii (C.R.P.Andrews) D.L.Jones & M.A.Clem.

Pterostylis sargentii commonly known as the frog greenhood, is a plant in the orchid family Orchidaceae and is endemic to the south-west of Western Australia. It is a relatively common orchid which has up to six relatively small, white flowers with green or brown stripes and a fleshy, three-part, frog-like labellum. Non-flowering plants have a rosette of leaves on a short stalk.

Description

Pterostylis sargentii, is a terrestrial, perennial, deciduous, herb with an underground tuber. Non-flowering plants have a rosette of between three and six leaves long and wide on a short stalk. Flowering plants lack a rosette but have between three and ten stem leaves which are long and wide on the flowering stem. Up to six white and green or brown striped flowers are borne on the flowering stem which is high. The flowers are long and wide. The dorsal sepal and petals form a hood or "galea" over the column with the dorsal sepal having a thread-like tip long. The lateral sepals turn downwards are joined for about half their length, then suddenly taper to narrow tips long. The labellum is long, about wide, dark brown with three lobes, the side ones with a large, horn-like appendage. Flowering occurs from July to October.

Taxonomy and naming

Pterostylis sargentii was first formally described in 1905 by the British educator, Cecil Rollo Payton Andrews and the description was published in Journal of the West Australian Natural History Society. The specific epithet (sargentii) honours the Western Australian pharmacist Oswald Sargent who collected the type specimen.

Distribution and habitat

The frog greenhood is found in a wide range of habitats throughout the south-west of Western Australia, but especially between Mullewa and Grass Patch.

Conservation

Pterostylis sargentii is classified as "not threatened" by the Western Australian Government Department of Parks and Wildlife.

External links

• Data related to Pterostylis sargentii at Wikispecies
• Media related to Pterostylis sargentii at Wikimedia Commons

• Cecil Rollo Payton Andrews