Bossiaea walkeri, commonly known as cactus bossiaea, cactus pea, or Walker's stick bush is a species of flowering plant in the pea family (Fabaceae) and is endemic to southern mainland Australia. It is a rigid, much-branched shrub with flattened, winged cladodes and red, pea-like flowers between July and November in the species' native range. Description Bossiaea walkeri is a rigid, much-branched shrub that grows up to high and wide and is more or less glabrous. The stems and branches are flattened and winged, ending in cladodes wide. The leaves, when present, are reduced to scales about long, occasionally more or less round and up to long near the base or on young plants. The flowers are long and are borne singly at nodes on the cladodes on a pendent pedicel up to long with overlapping, broadly egg-shaped bracts up to long at the base. There are egg-shaped bracteoles long on the pedicel, but that fall off as the flower opens. The five sepals are about long and joined at the base, forming a tube long, the two upper lobes long and much longer than the lower three. The standard petal is usually red, long and shorter than the wings and keel that are each about long. The wings are salmon pink and the keel is deep red. Flowering occurs between July and November and the fruit is an oblong pod about long. Taxonomy Bossiaea walkeri was first formally described in 1861 by Ferdinand von Mueller in Fragmenta Phytographiae Australiae from specimens collected by Alexander Walker on hills between the Lachlan and Murrumbidgee Rivers. The specific epithet (walkeri) honours the collector of the type specimens. Distribution and habitat Cactus bossiaea grows in mallee, low open woodland, creek beds and rocky outcrops and occurs in Western Australia, South Australia, Victoria and New South Wales. It is found from near Shark Bay in Western Australia, through the south-west of the state to southern South Australia, the Murray River and Wyperfeld National Park in Victoria, and to inland New South Wales. The species is rare in Victoria, where it is listed as "endangered" under the Victorian Government Flora and Fauna Guarantee Act 1988. Ecology The pendent flowers and the unusual shape of the flower parts of B. walkeri suggest that it is bird-pollinated. Honeyeaters and blue wrens have been observed visiting the flowers. Reproduction The 2cm flowers are produced between July and November. They