Swainsona formosa

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 4–8 mm (0.16–0.31 in) wide. The leaves are mostly 100–150 mm (3.9–5.9 in) long with about 15 elliptic to egg-shaped leaflets 100–300 mm (3.9–11.8 in) long and 5–12 mm (0.20–0.47 in) wide, the end leaflet slightly longer. There are broad, densely hairy stipules, sometimes 15 mm (0.59 in) or more at the base of the petiole.

The flowers are borne in racemes about 100–150 mm (3.9–5.9 in) long with 2 to 6 usually red flowers, sometimes white or other colours, on a peduncle 50–150 mm (2.0–5.9 in) long, each flower on a shaggy-hairy pedicel 5–20 mm (0.20–0.79 in) long. The sepals are joined at the base, forming a bell-shaped tube 5–6 mm (0.20–0.24 in) long with narrowly egg-shaped lobes with thread-like tips, the lobes twice as long as the tube. The standard petal is 40–60 mm (1.6–2.4 in) long and very narrow, the base domed into a usually black, shiny boss. The wings are 35–40 mm (1.4–1.6 in) long, tapering to a narrow point, and the keel 50–60 mm (2.0–2.4 in) long and 12–15 mm (0.47–0.59 in) deep with a narrow tip. Flowering occurs from June to October, and the fruit is a hairy pod or follicle 40–90 mm (1.6–3.5 in) long, 10–12 mm (0.39–0.47 in) wide and round in cross-section, with a stalk 5–15 mm (0.20–0.59 in) long and the remains of the style about 30–40 mm (1.2–1.6 in) long.