Swainsona formosa is a prostrate annual or short lived perennial herb, with several densely softly-hairy stems mostly 4–8 mm (0.16–0.31 in) wide.

[3][4][5][6] Most forms of the plant are low-growing or prostrate, however in the Pilbara region of north-western Australia varieties growing as tall as 2 metres have been observed.

[7] Specimens of Sturt's desert pea were first collected by William Dampier who recorded his first sighting on 22 August 1699 on Rosemary Island.

[8][9] The first formal description of the species was in 1832 by George Don, who gave it the name Donia formosa in his A General History of the Dichlamydeous Plants.

[12] In 1950, Neridah Clifton Ford and Joyce Winifred Vickery transferred Don's Donia formosa to Clianthus as C. formosus in Contributions from the New South Wales National Herbarium, with a description of the genus, the type species endemic to New Zealand.

[8] Sturt's desert pea (described as Clianthus formosus) was adopted as the floral emblem of the state of South Australia on 23 November 1961.