Coiled Cassia

The Coiled Cassia (Senna circinnata) is a shrubby legume in the family Fabaceae, native to inland arid and semi-arid regions of Australia, particularly the mulga woodlands and shrublands of Queensland, New South Wales, South Australia, and the Northern Territory. The common name 'coiled cassia' refers to the distinctive spirally coiled seed pods that develop after flowering—a morphological feature unique among Australian Senna species and immediately recognisable in the field. Plants typically grow 0.5–2 metres tall, with pinnate leaves and bright yellow flowers characteristic of the genus Senna. Like other acacias and legumes in arid Australian landscapes, Senna circinnata contributes to nitrogen fixation in nutrient-poor desert soils through root nodule symbiosis with rhizobia bacteria, benefiting the broader plant community. The species is drought-tolerant and well-adapted to the seasonal rainfall and thin soils of inland Australia, regenerating vigorously after fire and disturbance. It is assessed as Least Concern by the IUCN given its stable populations across a wide extent of occurrence within Australia's arid interior. Coiled Cassia provides browse for kangaroos and other herbivores and cover for small reptiles and birds in shrubland habitats.