Caladenia australis


Caladenia australis, commonly known as southern spider orchid, is a plant in the orchid family Orchidaceae and is endemic to Victoria, although it was also found on one Bass Strait island on one occasion in 1968. It has a single hairy leaf and usually only one creamy-yellow flower with red streaks, the flower on a hairy stalk.

Description

Caladenia australis is a terrestrial, perennial, deciduous, herb with an underground tuber and a single hairy leaf, long and wide.
There is usually only a single flower on a thin, wiry, sparsely hairy spike high, each flower wide. The dorsal sepal curves forward or droops over the rest of the flower. All three sepals are long, wide and taper to a thin end with dark red, club-like glands. The petals are a similar size and shape to the sepals but lack glandular ends. The petal and sepals spread widely, sometimes drooping near their ends and are a creamy-yellow colour, often with red streaks. The labellum is shiny, yellowish with a maroon tip and curves forward, with the tip rolled under at the end. It is egg-shaped, long and about wide. The edges of the labellum have many teeth up to long and there are 4 to 6 rows of dark red calli along the labellum mid-line, decreasing in size towards the front. Flowering occurs between September and November and is strongly enhanced by fires the previous summer.

Taxonomy and naming

The species was first formally described by Geoffrey Carr in 1991 and the description was published in Indigenous Flora and Fauna Association Miscellaneous Paper 1. The type specimen was collected on Wilsons Promontory. The specific epithet is a Latin word meaning "southern".

Distribution and habitat

Caladenia australis mostly grows in near-coastal areas of Victoria and although widespread, is also uncommon. It grows in heath and woodland, usually on sandy soil. There is a single record from the southern part of Flinders Island in 1968.

Conservation

There are insufficient data to make an assessment of the conservation status of southern spider orchid in Victoria but it is listed as "Endangered" under the Tasmanian "Threatened Species Protection Act 1995".