N. Vietnam, prov. Lai Chau, about 50 km downstream along Black river (Song Da), from Lai Chau town (N 22°03′ E 103°09′) to Nam Ma village (distr. Sin Ho). Open shale and limestone rocks on steep slopes of the river at elev. about 220 m. Forb vine 3-4 m lg on open shrubs along river slope. Common.
NTH 2732 24 May 1999
International Botanical Expedition of the U.S.A. National Geographic Society (grant No 6300-98)