Microtis rara, commonly known as the scented onion orchid, is a species of orchid endemic to Australia, with the exception of the Northern Territory. It has a single hollow, onion-like leaf and up to fifty small green or yellowish-green, scented flowers. It is similar to Microtis oblonga and some authorities regard the two as being one species.
Microtis rara is a terrestrial, perennial, deciduous, herb with an underground tuber and a single erect, tapering, tubular leaf NaNsigfig=1NaNsigfig=1 long and NaNsigfig=1NaNsigfig=1 wide. Between ten and fifty green or greenish-yellow flowers are well spaced along a flowering stem NaNsigfig=1NaNsigfig=1 tall. The flowers sweetly scented, NaNsigfig=2NaNsigfig=2 long and NaNsigfig=1NaNsigfig=1 wide. The dorsal sepal is egg-shaped, NaNsigfig=1NaNsigfig=1 long, NaNsigfig=1NaNsigfig=1 wide with a dished lower surface. The lateral sepals are linear to oblong, NaNsigfig=1NaNsigfig=1 long, about 1sigfig=1NaNsigfig=1 wide with their tips rolled under. The petals are a curved lance shape, NaNsigfig=1NaNsigfig=1 long, about 1sigfig=1NaNsigfig=1 wide and spread widely apart. The labellum is more or less oblong, NaNsigfig=1NaNsigfig=1 long, NaNsigfig=1NaNsigfig=1 wide with notched edges and a narrowed middle section. There are dark green calli in the centre of the labellum. Flowering occurs from November to January and is stimulated by fire the previous summer.[1] [2] [3] [4]
Microtis rara was first formally described in 1810 by Robert Brown and the description was published in Prodromus Florae Novae Hollandiae et Insulae Van Diemen.[5] [6] The specific epithet (rara) is a Latin word meaning "scarce", "scattered" or "dispersed".[7]
Some authorities regard Microtis oblonga as being a race of M. rara.[8]
The scented onion orchid grows swamps and wet forests and is widespread but not common, occurring in all states but not the Northern Territory.