It is a prostrate or climbing perennial growing up to 3 m high, with purple-blue-pink flowers from February to November.[2] Juvenile form is a vine, maturing into a woody-stemmed shrub with vine-like stems. Leaves are broad and leathery, 4-9 cm long.[4] Tubers are rounded, 12-20 cm long by 5-18 cm wide, with a single plant potentially having up to twenty tubers.[6]
Habitat
It occurs on sandy or rocky soils, often over limestone,[2] and on spinifex sand plains in northern Australia.[4]
Uses
It is the source of bush potato, a bush tucker food for Aboriginal people.[4] Bush potatoes are cooked on the warm earth under coals, and are peeled when cooked.[6]
Aboriginal names
In Central Australia, I. costata is also known to Aboriginal people by the following names:[7]
