N. Vietnam, prov. Cao Bang, distr. Thach An, about 28 km to SE from Cao Bang town (N 22°29′ E 106°28). Primary evergreen broadleaved closed wet forest along deep shadow canyon of remnant limestone ridge at 300-400 m alt. Epilite and terrestrial herb on steep shadow slopes. Flowers blue-violet. Not rare.
CBL 949 06 Dec. 1998
International Botanical Expedition of the U.S.A. National Geographic Society (grant No 6300-98)