Begonia rubinea (sect. Platycentrum, Begoniaceae), a new species from Guizhou, China

Begonia rubinea (sect. Platycentrum), a new species from Guizhou Province, China, is described and illustrated. Its chromosome number (2n = 22) and pollen morphology are reported. Begonia rubinea was collected from a small damp cliff in Changqiangou, Xishui National Reserve of Evergreen Arbor Forest, in Guizhou. It resembles B. smithiana T.T. Yu ex Irmsch. in aspect, but is distinct by the combination of the following characters: leaves thinly coriaceous and glossy, sparsely hispidulous; leaf margin entire or remotely shallowly denticulate; petioles glabrous; androecium zygomorphic, stamens few (15-30), androphore distinct, 2-3 mm long; and ovary glabrous or nearly so. Line drawings of B. rubinea and color photographs of both B. rubinea and B. smithiana are presented to aid in identification.