Swainsona microphylla



Swainsona microphylla, commonly known as small-leaf swainson-pea, small-leaf swainsona, or poison swainson-pea is a species of flowering plant in the family Fabaceae and is endemic to mainland Australia. It is a prostrate or low-growing, sometimes erect perennial herb, with imparipinnate leaves with mostly 21 to 41 broadly wedge-shaped to round leaflets and racemes of 5 to 10 white, pink or purple flowers.

Description
Swainsona microphylla is a prostrate or low-growing, sometimes erect perennial herb that typically grows to a height of up to 60 cm long and sometimes has softly-hairy branches. The leaves are imparipinnate, mostly 50–150 mm long with mostly broadly wedge-shaped to round leaflets, the leaflets 1–5 mm long and wide with stipules 1–4 mm long at the base of the petioles. The flowers are white, pink or purple, arranged in racemes of 10 to 25, on a peduncle 10–30 mm wide, each flower 6–10 mm long on a pedicel 1–2 mm long. The sepals are joined at the base to form a tube about 1 mm long, with teeth much shorter than the tube. The standard petal is 6–8 mm long and 6–9 mm wide, the wings 6–7 mm long and the keel 4.5–7 mm long and 2–3 mm broad. The fruit is an almost spherical pod 5–10 mm long and 3–9 mm wide with the remains of the style 2–4 mm long.

Taxonomy and naming
Swainsona microphylla was first formally described in 1854 by Asa Gray in the United States Exploring Expedition Phanerogamia. The specific epithet (microphylla) means "small-leaved".

Distribution
This species of pea grows in sandy soils on sandplains and sand hills, and is found in all mainland Australian states and the Northern Territory. In Victoria, it is mainly restricted to the far north-west of that state. In New South Wales, it is found on the western slopes and plains. In Western Australia it is widespread in inland areas. In South Australia, the species is widespread in scattered areas and in the Northern Territory it occurs in the south.