N. Vietnam, prov. Cao Bang, distr. Nguyen Binh, municipality Nguyen Binh (N 22°37′ E 105°52′), about 41 km to W from Cao Bang town. Elevation from Le A pass to Na Ni mt. peak at 1400-1900 m alt. Old secondary closed evegreen wet mountain forest. On open wet steep slopes. Rare. CBL 145 11-12 Nov. 1998 International Botanical Expedition of the U.S.A. National Geographic Society (grant No 6300-98)