Commonly called greenhood orchids, they are terrestrial, deciduous, perennial, tuberous, herbs found in Australia, New Zealand, New Guinea, New Caledonia and one Indonesian island.

The galea curves forward, covers the sexual parts of the flower, is important in the pollination process and is about as long as the two petals.

[3][5] The first observation of Pterostylis by European botanists was probably by Joseph Banks when HMS Endeavour visited Botany Bay in 1770 but any specimens collected were lost later in the voyage.

The first formal description of a greenhood was by Jacques Labillardière who collected a specimen from Bruny Island and gave it the name Disperis alata.

John White, the first surgeon-general of the colony of New South Wales collected several species and George Caley collected 208 greenhood specimens from 16 species and described them in great detail, including details of their habitat and gave them names like Druids Cap patersoni but did not publish his work.

The species he described were collected from the east coast of the mainland and from Tasmania and the descriptions were published in Prodromus Florae Novae Hollandiae.

The following year, David Jones and Mark Clements proposed further separating Pterostylis into sixteen genera based on a combination of molecular and morphological characters: the genera Bunochilus, Crangonorchis, Diplodium, Eremorchis, Hymenochilus, Linguella, Oligochaetochilus, Petrorchis, Pharochilum, Plumatichilos, Ranorchis, Speculantha, Stamnorchis, Taurantha and Urochilus.

They grow in a wide range of habitats, especially in temperate zones and are found in grassland, heath, scrub, woodland and forest, including rainforest.

(In the case of Pterostylis sanguinea, the pollinator is a male fungus gnat of the genus Mycomya which attempts to copulate with the labellum, which produces the chemical attractant.