Redefinition of Tephrosia supina (Fabaceae: Millettiae), a north-west Western Australian endemic, and description of two similar species

The application of the name Tephrosia supina Domin is clarified herein, with this species determined as being a north-west Western Australian endemic subshrub with pink-purple flowers; T. supina s. str. is differentiated from two similar taxa, which also occur in the Northern Territory and Queensland. These are described herein as T. insolens R.Butcher & Cowie and T. lithosperma R.Butcher & Cowie, and T. supina is lectotypified. Full descriptions and images are provided for these three species and their histories and affinities are discussed.