Prasophyllum calcicola

Prasophyllum calcicola, commonly known as limestone leek orchid, is a species of orchid endemic to Australia. It has a single, smooth, tube-shaped leaf and up to twelve yellowish-green flowers on an erect flowering stem. It is found in coastal areas of Western Australia and South Australia growing on soils derived from limestone.

Description
Prasophyllum calcicola is a terrestrial, perennial, deciduous, herb with an underground tuber and a single smooth, tube-shaped leaf which is 50-150 mm long and about 2 mm in diameter near the reddish base. Between three and twelve or more flowers are arranged on a flowering spike. The flowers are yellowish-green, about 4 mm long and 3 mm wide. 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, about 2 mm long, 2-3 mm wide and green with a red edge. The lateral sepals are lance-shaped, 2-4 mm long and joined to each other for about half their length. The petals are triangular in shape, about 2 mm long and 1 mm wide. The labellum is 2-3 mm long, oblong to lance-shaped and turns upward at 90° about half-way along. Flowering occurs in September and October.

Taxonomy and naming
Prasophyllum calcicola was first formally described in 1989 by Robert Bates and the description was published in Journal of the Adelaide Botanic Garden from a specimen he collected in the Warrenben Conservation Park. The specific epithet (calcicola) is derived from the Latin words calx meaning "limestone"  and -cola meaning "dweller",  referring to the usual habitat of this species.

Distribution and habitat
The limestone leek orchid grows in coastal areas in calcareous sand and near limestone. It occurs between north of Geraldton and Israelite Bay in Western Australia and in the south-east of South Australia.

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