N. Vietnam, prov. Son La, distr. Moc Chau, municipality Chieng Hac, vicinities of Co Liu village (N 20°51′ E 104°38′). Primary evergreen broadleaved wet forest on very steep slopes and bluffs of remnant karst limestone ridge at 1100-1200 m elev. Lithophyte forb on mossy wet rocks. Flowers white-greenish. Not common.
NTH 2963 29 May 1999
International Botanical Expedition of the U.S.A. National Geographic Society (grant No 6300-98)