Pterostylis dubia, commonly known as the blue-tongued greenhood, is a plant in the orchid family Orchidaceae and is endemic to Tasmania. It has a rosette of fleshy leaves at its base and a dark green and white flower with narrow petals and a dark blue-green labellum.
Pterostylis dubia, is a terrestrial, perennial, deciduous, herb with an underground tuber. It has a rosette of leaves which are NaNsigfig=1NaNsigfig=1 long, NaNsigfig=1NaNsigfig=1 wide and have a stalk. Flowering plant have a single dark green and white flower NaNsigfig=1NaNsigfig=1 long and NaNsigfig=1NaNsigfig=1 wide is borne on a flowering stem NaNsigfig=1NaNsigfig=1 tall with stalkless stem leaves. The dorsal sepal and petals are joined, forming a hood called the "galea" over the column. The petals are not flared and are similar in length to the dorsal sepal which ends in a point. There is a wide gap at each side of the flower between the galea and the lateral sepals. The lateral sepals are erect and have a tapering tip, NaNsigfig=1NaNsigfig=1 long, only slightly taller than the galea and there is a notch in the bulging sinus between them. The labellum is NaNsigfig=1NaNsigfig=1 long, about 3sigfig=1NaNsigfig=1 wide, dark bluish-green, curved and protrudes prominently above the sinus. Flowering occurs from November to January.[1] [2]
Pterostylis dubia was first formally described in 1810 by Robert Brown and the description was published in Prodromus Florae Novae Hollandiae et Insulae Van Diemen.[3] [4] The specific epithet (dubia) is a Latin word meaning "wavering", "uncertain" or "doubtful".[5]
The blue-tongued greenhood grows in wet forest at altitudes above 500sigfig=2NaNsigfig=2 in central and southern Tasmania.