Pterostylis allantoidea

Pterostylis allantoidea, is a terrestrial, perennial, deciduous, herb with an underground tuber and which usually grows in colonies. It has a rosette of large, dark green leaves with wrinkled edges, each leaf 5–15 mm (0.2–0.6 in) long and 1–10 mm (0.04–0.4 in) wide. When flowering, there is usually only a single, white flower with green or reddish-brown stripes. The flowers lean forwards and are 12–15 mm (0.5–0.6 in) long, 6–8 mm (0.2–0.3 in) wide and borne on a flowering spike 80–100 mm (3–4 in) tall. The dorsal sepal and petals form a hood over the column. The dorsal sepal is longer than the petals and has a thread-like tip 6–8 mm (0.2–0.3 in) long. The lateral sepals are erect with thread-like tips 10–14 mm (0.4–0.6 in) long with a bulging sinus between them. The labellum is egg-shaped, 4–5 mm (0.16–0.20 in) long, about 1 mm (0.04 in) wide, thick, fleshy, dark brown and curved and protrudes above the sinus. Flowering occurs from August to September.[3][4][5]

Pterostylis allantoidea was first formally described in 1940 by Richard Sanders Rogers in Transactions of the Royal Society of South Australia.[1][6] The specific epithet (allantoidea) is from the Latin allantoideus, 'sausage-shaped', referring to the shape of the labellum.[4]

The shy greenhood grows on and near granite outcrops under shrubs between Coolgardie, Ravensthorpe and Israelite Bay in the Coolgardie and Esperance Plains biogeographic regions of Western Australia.[4][5][7]

Pterostylis allantoidea is classified as "not threatened" by the Government of Western Australia Department of Parks and Wildlife.[7]