Diuris palustris
Diuris palustris, commonly known as the swamp doubletail or swamp diuris is a species of orchid which is endemic to south-eastern Australia. It has a tuft of between eight and ten twisted leaves and up to four yellow flowers with brown spots and blotches marks and blotches.

Description
Diuris palustris is a tuberous, perennial herb with a tuft of between eight and ten twisted, linear leaves  long,  wide and folded lengthwise. Up to four flowers  wide are borne on a flowering stem  tall. The flowers are yellow with dark brown spots and blotches. The dorsal sepal is erect, curved backwards near the tip, egg-shaped,  long and  wide. The lateral sepals are green,  long, about  wide, turned downwards and parallel to each other. The petals are erect to curved backwards, with an egg-shaped blade  long and  wide on a dark reddish brown stalk  long. The labellum is  long and has three lobes. The centre lobe is spatula-shaped,  wide and the side lobes are erect, oval,  long and  wide with rounded teeth near the tip. There are two ridged calli  long in the mid-line of the labellum. Flowering occurs from August to October.

Taxonomy and naming
Diuris palustris was first formally described in 1840 by John Lindley and the description was published in his book, The Genera and Species of Orchidaceous Plants. The specific epithet (palustris) is a Latin word meaning "marshy" or "boggy".

Distribution and habitat
The swamp doubletail is found in New South Wales, Victoria, Tasmania and South Australia where it is most common. It grows in moist or wet soil in forest, Callitris woodland and grassland.

Conservation
Diuris palustris is classed as "vulnerable" under the Victorian Flora and Fauna Guarantee Act 1988 and as "endangered" under the Tasmanian Threatened Species Protection Act 1995.

References

palustris
Orchids of South Australia
Orchids of Tasmania
Orchids of Victoria (state)
Endemic orchids of Australia
Plants described in 1840