Caladenia verrucosa, commonly known as the mallee spider orchid, is a plant in the orchid family Orchidaceae and is endemic to south-eastern Australia. It is a ground orchid with a single, hairy leaf and usually only one greenish-yellow and red flower.

Description
Caladenia verrucosa is a terrestrial, perennial, deciduous, herb with an underground tuber and a single hairy leaf,  long and  wide with reddish-purple blotches near its base. A single yellowish-green flower about  across and with central red stripes is borne on a spike  tall. The sepals have bright yellow, club-like glandular tips  long. The dorsal sepal is erect,  long and about  wide. The lateral sepals are  long,  wide and suddenly narrow at about half their length. The petals are  long, about  wide, linear to lance-shaped and turn obliquely downwards. The labellum is green with a dark red tip, and is  long and wide. The sides of the labellum turn upwards and have three to five green teeth up to  long and short red teeth on each side. There are four crowded rows of dark red, stalked calli which are up to  long near the base of the labellum but decreasing in size towards its tip. Flowering occurs from September to October.

Taxonomy and naming
Caladenia verrucosa was first formally described in 1991 by Geoffrey Carr and the description was published in Indigenous Flora and Fauna Association Miscellaneous Paper 1. The specific epithet (verrucosa) is a Latin word meaning "full of warts".

Distribution and habitat
The mallee spider orchid is most common in north-western Victoria and south-eastern South Australia where it grows in mallee woodland in sandy soil. In New South Wales it occurs in between Griffith and Rankins Springs.

References 

verrucosa
Plants described in 1991
Endemic orchids of Australia
Orchids of Victoria (state)
Orchids of South Australia
Orchids of New South Wales
Taxa named by David L. Jones (botanist)