Prasophyllum truncatum, commonly known as the truncate leek orchid, is a species of orchid endemic to Tasmania. It has a single tubular, dark green leaf and up to twenty whitish flowers with purplish and greenish-brown markings. It is a late-flowering leek orchid and its flowering is stimulated by earlier fire.
Prasophyllum truncatum is a terrestrial, perennial, deciduous, herb with an underground tuber and a single dark green, tube-shaped leaf which is NaNsigfig=1NaNsigfig=1 long and NaNsigfig=2NaNsigfig=2 wide near its red to purple base. Between ten and twenty whitish flowers with purplish and greenish-brown markings are loosely arranged along a flowering spike which is NaNsigfig=1NaNsigfig=1 long, reaching to a height of NaNsigfig=1NaNsigfig=1. The flowers are NaNsigfig=1NaNsigfig=1 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 lance-shaped to narrow egg-shaped, about NaNsigfig=2NaNsigfig=2 long, about 4sigfig=1NaNsigfig=1 wide with five purplish striations. The lateral sepals are linear to lance-shaped, NaNsigfig=2NaNsigfig=2 long, 1.5sigfig=1NaNsigfig=1 wide and free from each other. The petals are narrow linear, NaNsigfig=2NaNsigfig=2 long, about 1sigfig=1NaNsigfig=1 wide and white with a purplish central line. The labellum is white, oblong to elliptic in shape, about 8sigfig=1NaNsigfig=1 long, about 4sigfig=1NaNsigfig=1 wide and turns sharply backwards on itself near its middle. The edges of the upturned part of the labellum have crinkled edges and there is a greenish-yellow, fleshy, raised callus in its centre extending just past the bend. Flowering occurs from November to March, more prolifically after fire.[1] [2]
Prasophyllum truncatum was first formally described in 1840 by John Lindley from a specimen collected near Stanley and the description was published in The genera and species of Orchidaceous plants.[3] [4] The specific epithet (truncatum) is a Latin word meaning "maimed" or "cut off".[5]
The truncate leek orchid widely distributed but uncommon, growing with shrubs and herbs in woodland in both the north and south of Tasmania.