N. Vietnam, Hoa Binh prov., Da Bac distr., near Doan Ket village (20°54′58′'N, 105°03′51′'E). Primary broad-leaved evergreen wet forest on steep slopes of remnant highly eroded limestone ridge at elev. 750-900 m a.s.l., White Rock mt. (Nui Da Trang). Terrestrial and lithophyte herb up to 0.6 m hg on shady rocky slopes. Flowers greenish. Common.