N. Vietnam, Hoa Binh prov., Mai Chau distr., Hang Kia municipality, near Hang Kia village (20°43′39′'N, 104°53′43′'E). Primary broad-leaved evergreen wet forest on slopes of remnant limestone highly eroded ridge near ridge tops at elev. 1100-1300 m a.s.l. Shrub 2-3 m hg on tops of ridge. Flowers white. Not rare.