Diuris alba, commonly called the white donkey orchid, is a species of orchid which is endemic to eastern Australia. It has up to three leaves, and a flowering stem with up to seven white flowers with purplish markings.
Diuris alba is a tuberous, perennial herb, usually growing to a height of NaNsigfig=1NaNsigfig=1. There are up to three linear leaves arising from the base of the plant, each leaf NaNsigfig=1NaNsigfig=1 long, NaNsigfig=1NaNsigfig=1 wide and rolled so that the sides of the leaf face each other. There are between two and seven white flowers with lilac or purple markings arranged on a flowering stem, each flower about 20sigfig=1NaNsigfig=1 wide. The dorsal sepal is egg-shaped, NaNsigfig=1NaNsigfig=1 long and NaNsigfig=1NaNsigfig=1 wide with its margins turned downwards. The lateral sepals are linear to lance-shaped, NaNsigfig=1NaNsigfig=1 long, NaNsigfig=1NaNsigfig=1 wide and turned downwards, either parallel to each other or crossed. The petals are erect, ear-like above the flower, NaNsigfig=1NaNsigfig=1 long and NaNsigfig=1NaNsigfig=1 wide with a dark-coloured, stalk-like "claw" NaNsigfig=2NaNsigfig=2 long. The labellum is NaNsigfig=1NaNsigfig=1 long and has three lobes. The central lobe is a broad egg shape to almost circular, NaNsigfig=1NaNsigfig=1 wide with a raised midline. The lateral lobes are linear to lance-shaped with the narrower end towards the base, NaNsigfig=1NaNsigfig=1 long and NaNsigfig=1NaNsigfig=1 wide. There are two broad calli NaNsigfig=2NaNsigfig=2 long. Flowering occurs from August to November.[1]
Diuris alba was first formally described in 1810 by Robert Brown and the description was published in Prodromus florae Novae Hollandiae.[2] [3] The specific epithet (alba) is a Latin word meaning "white".[4]
The white donkey orchid occurs on the coast and nearby ranges of New South Wales and Queensland north from the Central Coast. It grows with grasses in forest.