Ophiorrhiza dianguiensis (Rubiaceae), a new species from southwestern China

Ophiorrhiza dianguiensis (Rubiaceae), a new species known from Guangxi and Yunnan provinces, China, along the China–Vietnam border, is described and illustrated. This species is morphologically similar to O. petrophila, but differs by its persistently erect inflorescences, distinctly longer corolla tubes that are swollen at the base, and narrower, subulate-linear bracts. Micromorphologically, O. dianguiensis has more sinuous leaf epidermal cell walls and a denser covering of tubercles on the testa. According to the IUCN Red List Categories and Criteria, its conservation status is assessed as “Least Concern” (LC).