In this study, Ophiorrhiza guizhouensis, a new species of Rubiaceae from south-western China, is described and illustrated. The new species is morphologically similar to O. japonica, but differs from the latter by having terete stems which are densely hirtellous, usually persistent ciliate stipules with well-developed colleters inside the base of the stipule, shorter corolla tubes and shorter stamens and styles.
Keywords: China; Guizhou; Ophiorrhiza; distyly; new taxa.