Microtis arenaria, commonly known as the notched onion orchid[1] or pale onion orchid,[2] is a species of orchid native to south-eastern Australia and New Zealand. It has a single hollow, onion-like leaf and up to sixty scented, crowded yellowish-green flowers. It is widespread and common, growing in a wide variety of habitats.
Microtis arenaria is a terrestrial, perennial, deciduous, herb with an underground tuber and a single erect, smooth, tubular leaf NaNsigfig=1NaNsigfig=1 long and NaNsigfig=1NaNsigfig=1 wide. Between ten and sixty yellowish-green, fragrant flowers are crowded along a flowering stem NaNsigfig=1NaNsigfig=1 tall. The flowers are NaNsigfig=2NaNsigfig=2 long and NaNsigfig=1NaNsigfig=1 wide. The dorsal sepal is egg-shaped, 2.5sigfig=1NaNsigfig=1 long and wide with its tip turned slightly upwards. The lateral sepals are 2.5sigfig=1NaNsigfig=1 long, about 1sigfig=1NaNsigfig=1 wide with their tips rolled under. The petals are lance-shaped but curved, about 2sigfig=1NaNsigfig=1 long, 1sigfig=1NaNsigfig=1 wide and are held under the dorsal sepal. The labellum curves downwards and is NaNsigfig=1NaNsigfig=1 long, about 1.3sigfig=1NaNsigfig=1 wide with scalloped edges and a shallow notch at the tip between two prominent lobes. There is an irregularly-shaped callus in the centre of the labellum. Flowering occurs from September to January.[3]
Microtis arenaria was first formally described in 1840 by John Lindley and the description was published in The Genera and Species of Orchidaceous Plants.[4] [5] The specific epithet (arenaria) is a Latin word meaning "sandy".[6]
The pale onion orchid is widespread and common in south-eastern New South Wales, throughout Victoria, Tasmania and south-eastern South Australia. It grows in a range of habitats from sandhills to rocky inland outcrops but is most common in coastal sand.[7] Microtis arenaria also occurs on the North Island of New Zealand.[8] [9]