Prasophyllum rostratum
Prasophyllum rostratum, commonly known as the slaty leek orchid, is a species of orchid endemic to Tasmania. It has a single tubular leaf and up to twenty five well-spaced, greenish-brown flowers. It is similar to P. pyriforme from mainland Australia but lacks that species' white to pinkish labellum.
Description
Prasophyllum rostratum is a terrestrial, perennial, deciduous, herb with an underground tuber and a single tube-shaped leaf which is long and wide. Between ten and twenty five greenish to greenish-brown flowers are loosely arranged along a flowering spike which is long reaching to a height of. The flowers are long and wide and as with other leek orchids, are inverted so that the labellum is above the column rather than below it. The dorsal sepal is long, about wide and the lateral sepals are long, about wide, curve backwards and are free from each other. The petals are long, about wide and curve forwards and slightly upwards. The labellum is long, about wide and turns sharply upwards near its middle. There is a raised, fleshy, more or less bulbous callus in its centre. The labellum has a tail-like tip. Flowering occurs from October to December and is strongly promoted by fires the previous summer.
Prasophyllum rostratum was first formally described in 1840 by John Lindley and the description was published in The Genera and Species of Orchidaceous Plants. The specific epithet is a Latin word meaning "beaked" or "curved", referring to the tail-like tip of the labellum.
Distribution and habitat
The slaty leek orchid grows in a range of heath and sedge habitats, mainly in the north and north-west of Tasmania.