Swainsona oligophylla



Swainsona oligophylla is a species of flowering plant in the family Fabaceae and is endemic to central Australia. It is usually a prostrate perennial plant with imparipinnate leaves with 5 to 7 egg-shaped leaflets, the narrower end towards the base, and racemes of 3 to 7 purple flowers.

Description
Swainsona oligophylla is a prostrate or occasionally ascending annual perennial plant, that typically grows to a height of about 15 cm and has many stems. The leaves are imparipinnate, mostly 10–40 mm long with 5 to 7 egg-shaped leaflets with the narrower end towards the base, mostly 2–15 mm long and 1–8 mm wide with stipules about 3 mm long at the base of the petioles. The flowers are purple, arranged in racemes of 3 to 7, 20–100 mm long, on a peduncle up to 0.5 mm long. The sepals are joined at the base to form a tube about 1.5 mm long, with lobes 3 or 4 times longer than the tube. The standard petal is 8–10 mm long, the wings about 7 mm long and the keel about 8–9 mm long and 2 mm deep. Flowering usually occurs from August to October, and the fruit is a cylindrical pod 12–15 mm long on a stalk about 1 mm long, with the remains of the strongly curved style about 4 mm long.

Taxonomy and naming
Swainsona oligophylla was first formally described in 1864 by George Bentham in Flora Australiensis from an unpublished description by Ferdinand von Mueller. The specific epithet (oligophylla) means "few-leaved".

Distribution
This species of swainsona is widespread in the south of the Northern Territory, north-eastern South Australia, south-western Queensland and north-western New South Wales, where it grows on clay-loam soils in well-watered areas.