N. Vietnam, Hoa Binh prov., Da Bac distr., near Doan Ket village (20º54'58''N, 105º03'51''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). Lithophyte on shady rocky very steep slope. Rare.