Erythrina vespertilio is a small, straggly tree, with thorns on the trunk and branches.
Leaves are bifoliolate or trifoliolate, 3-5in long with leaflets broadly wedge-shaped or 3-lobed, resembling a bat's open wings. The plant is deciduous in the dry season. Scarlet to orange-red pea flowers are borne in terminal racemes 2-20in long. Flowering usually occurs when the tree is leafless. The seeds are orange to dark yellow in color, bean-like. The species will grow in a wide range of soils as long as drainage is good and it has plenty of sun. Propagation is from seed or cuttings. Generally no seed treatment is required but light scarification may assist germination.
The species was first formally described by the botanist George Bentham in 1848 as part of Thomas Mitchell's work Journal of an Expedition into the Interior of Tropical Australia.
It was widely traditionally used by Aboriginal Australians in Central Australia for making woomeras and coolamons. The Warlpiri, among others, would use the wood to make shields, used either for warfare or ceremonially. These shields could then be used for making fire with the friction method. The bark is also considered to have traditional medicinal uses. The seeds are used to make decorations.