There are many thin teeth up to 7 mm (0.3 in) long along the sides of the labellum, but which decrease in size towards its tip and four or more rows of yellowish to reddish calli along its centre line.

[2][3][4] Caladenia ferruginea was first described by William Nicholls in 1947 and the description was published in The Victorian Naturalist.

[1] The specific epithet (ferruginea) is a Latin word meaning "rust-coloured"[5] referring to the colour of the flowers of this orchid.

[3] Rusty spider orchid is found between Perth and Albany in the Jarrah Forest, Swan Coastal Plain and Warren biogeographic regions where grows in a variety of habitats ranging from well-drained soil in woodlands to swamps which are flooded in winter.

[2][3][4][6] Caladenia ferruginea is classified as "not threatened" by the Western Australian Government Department of Parks and Wildlife.