N. Vietnam, prov. Cao Bang, distr. Tra Linh, municipality Quang Vinh (N 22°51′ E 106°14′), about 21 km from Cao Bang town to the N. Open secondary broadleaved forest with bamboos along tops of remnant limestone ridge at 800-850 m alt. Epilite herb on open vertical cliffs. Flowers blue-violet. Common.
CBL 1003 09 Dec. 1998
International Botanical Expedition of the U.S.A. National Geographic Society (grant No 6300-98)