N. Vietnam, prov. Cao Bang, distr. Tra Linh, municipality Co Muoi, vicinities of Lung Dat village (N 22°51′ E 106°14′), about 22 km from Cao Bang town to the N. Primary mixed semideciduous forest (with Pseudotsuga brevifolia) along tops of limestone ridge at 900-1000 m alt. Herb vine up to 3 m lg. Very common on steep slopes and vertical cliffs.
CBL 1128 12 Dec. 1998
International Botanical Expedition of the U.S.A. National Geographic Society (grant No 6300-98)