Caladenia busselliana

Caladenia busselliana is a terrestrial, perennial, deciduous, herb with an underground tuber and a single erect, hairy leaf 20–30 cm (8–10 in) long and 5–10 mm (0.2–0.4 in) wide. There are up to three pale yellow flowers on a stem 20–30 cm (8–10 in) high. The flowers are 6–10 cm (2–4 in) long and 5–8 cm (2–3 in) wide. The lateral sepals and petals spread widely and the sepals are thickened. The labellum is pale yellow to white and lacks the red tip common to similar spider orchids. The sides of the labellum have narrow teeth or calli which have a "clubbed" end. There are four or more rows of red-tipped calli along the centre of the labellum. Flowering occurs between September and October and is followed by a non-fleshy, dehiscent capsule containing a large number of seeds.[2][3][4]

Caladenia busselliana was first formally described by Stephen Hopper and Andrew Brown in 2001 from a specimen collected by Greg Bussell near Quindalup and the description was published in Nuytsia.[1] The specific epithet (busselliana) honours the collector of the type specimen.[2][3]

Bussell's spider orchid grows in swampy jarrah forest and marri woodland, often with green kangaroo paw, (Anigozanthos viridis) and the more common swamp spider orchid (Caladenia paludosa). It is only known from two small areas near Vasse and Yallingup at the northern end of the Leeuwin-Naturaliste ridge in the Swan Coastal Plain biogeographic region.[2][3][5][6]

Caladenia busselliana is classified as "endangered" under the Australian Government Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act) and as "rare flora" under the Western Australian Wildlife Conservation Act 1950.[5][6]