Pterostylis

thumb|right|Labelled diagram of Pterostylis metcalfei thumb|right|Pterostylis coccina, sepals and petals removed(1) - labellum(2) - hinge(3) - stigma(4) - pollinia

Pterostylis is a genus of about 300 species of plants in the orchid family, Orchidaceae. 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 flowers are mostly green, sometimes with brown, reddish or white stripes, and are distinguished from other orchids by their unusual flower structures and pollination mechanism.