Caladenia rileyi

Caladenia rileyi, commonly known as the Gillenbah spider orchid, is a plant in the orchid family Orchidaceae and is endemic to New South Wales. It is a ground orchid with a single leaf and a single yellowish-green and red flower.

Description
Caladenia rileyi is a terrestrial, perennial, deciduous, herb with an underground tuber and a single leaf, 40-100 mm long and 6-8 mm wide. A single yellowish-green and red flower is borne on a spike 80-250 mm tall. The sepals and petals have thick, brownish, club-like glandular tips 6-25 mm long. The dorsal sepal is erect, 40-55 mm long and 2-3 mm wide. The lateral sepals are 40-55 mm long, 3-4 mm wide and are parallel to each other and held below horizontal. The petals are 30-40 mm long, about 2 mm wide and also turned slightly downwards. The labellum is 17-20 mm long and 18-20 mm wide and greenish-white with a dark red tip. The sides of the labellum turn upwards and have between four and six teeth up to 6 mm long. The tip of the labellum curls downwards and there are four rows of crowded calli up to 3 mm long, along its mid-line. Flowering occurs from September to October.

Taxonomy and naming
Caladenia rileyi was first formally described in 1997 by David Jones and the description was published in The Orchadian from a specimen collected in the Gillenbah State Forest near Narrandera.

Distribution and habitat
The Gillenbah spider orchid grows in Callitris woodland between Narrandera and Jerilderie on the south-west slopes of New South Wales.