Ophiorrhiza bibracteata (Rubiaceae), a new species from Guangxi, China

Ophiorrhiza bibracteata (Rubiaceae), a new species from northwest Guangxi, China, is described and illustrated. It can be distinguished from its allies O. mitchelloides, O. nanlingensis and O. grandibracteolata by the shape and size of the bracts (ovate, 8–11 mm long) and the shape and size of the calyx lobes (triangular, 0.8–1.0 mm long, glabrous, with glands between the lobes). According to the IUCN Red List Categories and Criteria, the new species is assessed as Data Deficient (DD) until more information becomes available.