Prasophyllum dossenum

Prasophyllum dossenum is a species of orchid endemic to a small area of northern New South Wales. It has a single tubular, dark green leaf and up to thirty scented pinkish-white and greenish-brown flowers crowded along an erect flowering stem. It is a rare orchid which grows in grassy places on the Northern Tablelands of New South Wales.

Description
Prasophyllum dossenum is a terrestrial, perennial, deciduous, herb with an underground tuber and which grows to a height of 200-500 mm. It has a single tube-shaped, dark green leaf 200-400 mm long and 5-10 mm wide with a reddish base. Between five and thirty flowers are crowded along a flowering spike 30-80 mm long. The flowers are scented, pinkish-white and greenish-brown. As with others in the genus, the flowers are inverted so that the labellum is above the column rather than below it. The dorsal sepal is egg-shaped to lance-shaped, 7-11 mm long, 4-5 mm wide, dark brown on the lower surface and has three stripes on the upper surface. The lateral sepals are linear to lance-shaped, dark purplish-brown, 7-11 mm long and about 2.5 mm wide with a swollen base then joined for part of their length but with free tips. The petals are linear to lance-shaped, 8-10 mm long, about 3 mm wide and spread widely apart from each other. The labellum is egg-shaped, 9-12 mm long, 5-6 mm wide, swollen near the base and turns upwards at about 90° near its middle. The edge of the labellum flares widely and is wavy near its tip. There is a fleshy, yellowish-green, channelled callus in the centre of the labellum. Flowering occurs from November to January and the flowers remain open for up to two weeks.

Taxonomy and naming
Prasophyllum dossenum was first formally described in 1991 by David Jones from a specimen collected near Guyra and the description was published in Australian Orchid Research. The specific epithet (dossenum) is a Latin word meaning "hunchback" or "humpback", referring to the swollen lateral sepals.

Distribution and habitat
This leek orchid grows in grassy places at altitudes higher than 800 m on the New England Tableland.