Genus termed monotypic as it only contains 1 species of annual, aromatic, herbaceous plant, B. polystachyon. It has an erect growth habit and foliage with smooth to symmetrically toothed margins. These leaves are ovate to triangular in shape and flowers are produced in unbranched raceme structures measuring around 5-6cm long. These are small, measuring around 2.5-3mm in length, coloured mauve-pink with velvety hairs on the inner flower surface. This genus is found in Africa, Madagascar, Southern Asia, New Guinea, Australia and numerous Pacific and Indian Oceanic islands.