Pterostylis

Pterostylis R.Br.

Greenhoods, Shell, Bird, Snail Orchids

Robert Brown in Prodr.Fl.Nov.Holland. 326 (1810)

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Pterostylis species generally have a smooth flowering stem (there are a few with hairy flower stems) and up to 25 translucent, dull green, brown or reddish-brown and white to greenish-white flowers on an erect inflorescence. The dorsal sepal and petals are united and form a hood over the column. The two lower sepals are united at the base and the labellum is usually irritable, small and tongue like with a spur at its base. With the exception of the Snail Orchids (Pterostylis nana complex) and Jug Orchid (P. recurva) the labellum often protrudes through the enclosure formed by the sepals and petals. Unlike most Western Australian geophytic orchids which have a solitary leaf, Pterostylis species have multiple leaves. These can be a flattened to slightly ascending rosette of up to 20 or more leaves encircling the base of the flowering stem or several cauline leaves. In some species a basal rosette is found in both flowering and non-flowering plants while in others the rosette is present only in non-flowering plants.