Pterostylis

Pterostylis is a terrestrial deciduous genus of some 200 or so species of orchids found in central and eastern Indonesia, New Zealand, Australia, New Guinea and New Caledonia. The common name of this orchid is greenhood - a number of species have green flowers with the dorsal sepal forming a "hood" over the rest of the flower. The name Pterostylis is based on the Greek words meaning winged column (pteron - a wing, stylis - a column). In a number of species, the flower has a hinged lip that swings backwards when touched by an insect, forming a tube with the column and wings. The trapped insect is then forced to crawl out of the tube, removing the pollinia in the process.