Swainsona formosa, commonly known as Sturt's desert pea or Sturt pea, is a species of flowering plant in the family Fabaceae and is native to the Northern Territory and all continental states of Australia, with the exception of Victoria. It is a prostrate annual or short lived perennial herb with imparipinnate leaves with about 15 elliptic to egg-shaped leaflets with the narrower end towards the base, and presents two to six racemes of usually red flowers.
Description
Swainsona formosa is a prostrate annual or short lived perennial herb, with several densely softly-hairy stems mostly wide. The leaves are mostly long with about 15 elliptic to egg-shaped leaflets long and wide, the end leaflet slightly longer. There are broad, densely hairy stipules, sometimes or more at the base of the petiole.
The flowers are borne in racemes about long with 2 to 6 usually red flowers, sometimes white or other colours, on a peduncle long, each flower on a shaggy-hairy pedicel long. The sepals are joined at the base, forming a bell-shaped tube long with narrowly egg-shaped lobes with thread-like tips, the lobes twice as long as the tube. The standard petal is long and very narrow, the base domed into a usually black, shiny boss. The wings are long, tapering to a narrow point, and the keel long and deep with a narrow tip. Flowering occurs from June to October, and the fruit is a hairy pod or follicle long, wide and round in cross-section, with a stalk long and the remains of the style about long.
Taxonomy and naming
Specimens of Sturt's desert pea were first collected by William Dampier who recorded his first sighting on 22 August 1699 on Rosemary Island. These specimens are today in the Fielding-Druce Herbarium at the University of Oxford in England.
thumb|Sturt's Desert Peas at The [[Australian Inland Botanic Gardens.]]
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. In 1835, John Lindley transferred the species to Clianthus as C. dampieri, but that name was illegitimate because there was no formal description of the genus. 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. In 1990, Joy Thompson transferred the species to Swainsona as S. formosa, and the name is accepted by both Plants of the World Online The specific epithet (formosa) means "finely formed", "handsome" or "beautiful".
In 1999, Alex George proposed to transfer the species to the monotypic genus Willdampia, but the move was not accepted.
Common names
The first recorded uses of common names for Swainsona formosa (Author/publication and year of first use).: