Siratro is a perennial twining plant in the pea family, developing stems up to 3 m long. The leaves have 3 ovate leaflets up to 7 cm long, with the two laterals ones markedly asymmetric, with a lobe on the base. The flowers are borne on slender racemes up to 40 cm long. The typical pea flowers are about 2 cm long and are dark reddish-black. Seed pods are pubescent, up to 10 cm long by 5 mm wide, with about 12 seeds to a pod.

flowering branch
North-eastern New South Wales, 4th January 1992

Siratro is native to Central and North America and is introduced in farm land and along roadsides in New South Wales north of Sydney, Queensland and the Northern Territory.

The foliage is food for some Caterpillars, for example :

Euchrysops cnejus (Cupid) LYCAENIDAE

Lampides boeticus (Pea Blue) LYCAENIDAE