Microtis alba

Microtis alba, commonly known as the white mignonette orchid or slender onion-orchid, is a species of orchid endemic to the south-west of Western Australia. It has a single hollow, onion-like leaf and up to sixty small, green and white flowers with a strong musky fragrance. It is much more common after a fire the previous summer than in unburned country.

Description
Microtis alba is a terrestrial, perennial, deciduous, herb with an underground tuber and a single erect, smooth, tubular leaf 100-500 mm long and 7-10 mm wide. Between ten and sixty green and white flowers are arranged along a flowering stem 200-800 mm tall. The flowers have a strong musky fragrance, lean downwards and are 5-8 mm long and 3-4 mm wide. The dorsal sepal is 4-5 mm long, about 2 mm wide and forms a hood over the column. The lateral sepals are 3-4 mm long, about 1 mm wide with their tips rolled under. The petals are 3-4 mm long, about 1 mm wide and often curved. The labellum is oblong to wedge-shaped, 4-7 mm long, 1-2 mm wide with wrinkled edges and a notched tip. Flowering occurs from October to January but much more prolifically after fire the previous summer.

Taxonomy and naming
Microtis alba was first formally described by Robert Brown in 1810 and the description was published in Prodromus Florae Novae Hollandiae et Insulae Van Diemen. The specific epithet (alba) is a Latin word meaning "white".

Distribution and habitat
The white mignonette orchid grows in a range of habitats from seasonally wet flats to forest and occurs between Dongara and Israelite Bay.

Conservation
Microtis alba is classified as "not threatened" by the Western Australian Government Department of Parks and Wildlife.