Pterostylis depauperata, commonly known as the keeled greenhood, is a species of orchid endemic to Queensland. Flowering plants have a rosette of leaves at the base of a flowering stem with a single small white flower with pale green marks, and a few small stem leaves. Non-flowering plants only have a rosette of leaves. All three sepals on the flower have relatively long, thread-like tips.
Pterostylis depauperata is a terrestrial, perennial, deciduous, herb with an underground tuber and which often grows in colonies. Non-flowering plants have a rosette of between three and seven egg-shaped, greyish green leaves lying flat on the ground. Each leaf is NaNsigfig=1NaNsigfig=1 long and NaNsigfig=1NaNsigfig=1 wide. Flowering plants have a single flower NaNsigfig=1NaNsigfig=1 long and NaNsigfig=1NaNsigfig=1 wide on a flowering stem NaNsigfig=1NaNsigfig=1 high with a few small stem leaves. The flowers are white with pale green striations. The dorsal sepal and petals are fused, forming a hood or "galea" over the column. The dorsal sepal has a thread-like tip NaNsigfig=1NaNsigfig=1 long and lateral sepals are erect, held closely against the galea and have thread-like tips NaNsigfig=1NaNsigfig=1 long. The labellum is NaNsigfig=1NaNsigfig=1 long, about 3sigfig=1NaNsigfig=1 wide, dark brown and curved, and just protrudes above the sinus. Flowering occurs from March to August.[1] [2]
Pterostylis depauperata was first formally described in 1943 by Frederick Bailey from a specimen collected near Cairns. The description was published in the Botany Bulletin of the Queensland Department of Agriculture.[3]
The keeled greenhood grows with grasses and small shrubs in woodland and forest between Cooktown and Ravenshoe at altitudes above 500sigfig=2NaNsigfig=2.