N. Vietnam, prov. Cao Bang, distr. Bao Lac, municipality Yen Lac, vicinities of Yen Lac village (N 22°44′ E 105°50′). Primary open broadleaved semideciduous forest on vertical cliffs of karst remnant limestone ridge of N exposition at 1300 m elev. Creeping lithophyte vine up to 6-8 m lg. Not common.
CBL 1585 20 April 1999
International Botanical Expedition of the U.S.A. National Geographic Society (grant No 6300-98)