Pterostylis barbata


Pterostylis barbata, commonly known as the western bearded greenhood or bird orchid is a species of orchid endemic to the south-west of Western Australia. Flowering plants have a rosette of leaves at the base of the plant and a single translucent white flower with dark green veins on a flowering stem with up to 20 stem leaves. It is one of a number of bearded orchids, some of which have yet to be formally described, all of which have a distinctive feather-like labellum.

Description

Pterostylis barbata is a terrestrial, perennial, deciduous, herb with an underground tuber and when not flowering, a rosette of stalkless, pointed leaves. Flowering plants have a similar rosette and between ten and twenty stem leaves. The leaves are long, wide and dark green with pale areas. There is usually only a single flower long and wide on a flowering stem tall. The flower leans slightly forward and is shiny, pale translucent green with darker green veins and purple-brown markings at the front. The sepal and petals are fused, forming a hood or "galea" over the column and the dorsal sepal has a thin point long. The sepals are joined at their bases which are dark reddish and the free part is narrow, green and long. The labellum is long and feather-like with a few pale yellow, thread-like branches and a dark brown knob on the end. Flowering occurs from July to September.

Taxonomy and naming

Pterostylis barbata was first formally described in 1840 by John Lindley and the description was published in A Sketch of the Vegetation of the Swan River Colony. The specific epithet is a Latin word meaning "bearded".

Distribution and habitat

The western bearded orchid grows in shrubby woodland and forest, often in thick Casuarina leaf litter and often in small clumps. It occurs between Bindoon and Albany and is common in the Darling Range near Perth. Its range includes the Avon Wheatbelt, Esperance Plains, Jarrah Forest, Mallee, Swan Coastal Plain and Warren biogeographic regions.
There are twelve undescribed species of Pterostylis in Western Australia and the range of this species may be redefined when those descriptions are published.

Conservation

Pterostylis barbata is classified as "not threatened" by the Western Australian Government Department of Parks and Wildlife.