Diuris drummondii


Diuris drummondii, commonly known as the tall donkey orchid is a species of orchid which is endemic to the south-west of Western Australia. It is the tallest Diuris and is distinguished from the similar Diuris emarginata by its larger, more widely spaced flowers. The flowers are pale yellow with brown markings.

Description

Diuris drummondii is a tuberous, perennial herb, growing to a height of with between three and six leaves, each long and wide. There are between three and seven pale yellow flowers with brown markings and wide. The sepal is erect, long, wide. The sepals are long, wide and turned downwards. The petals are held ear-like above the rest of the flower with the blade long and wide on a blackish stalk long. The labellum is long and has three lobes. The centre lobe is broadly egg-shaped, long and wide and the side lobes are long and wide. There are two parallel callus ridges long and edged with brown in the mid-line of the labellum. Flowering occurs from November to January and is enhanced by fire the previous summer followed by heavy winter rains.

Taxonomy and naming

Diuris drummondii was first formally described in 1840 by John Lindley and the description was published in A Sketch of the Vegetation of the Swan River Colony as an appendix to Edwards's Botanical Register. The specific epithet honours James Drummond who collected the type specimen.

Distribution and habitat

The tall donkey orchid grows in winter-wet depressions that retain at least some moisture until summer, and often flowers with its base submerged. It is found between Northampton and Mount Barker in the Avon Wheatbelt, Jarrah Forest, Swan Coastal Plain and Warren biogeographic regions.

Conservation

Diuris drummondii is classified as "Threatened Flora " by the Western Australian Government Department of Parks and Wildlife.