N. Vietnam, Thanh Hoa prov., Ba Thuoc distr., Eo Dieu municipality, territory of Pu Luong protected area, near Eo Dieu village (20°25′48′'N, 105°14′13′'E). Primary wet broad-leaved evergreen forest along tops of remnant highly eroded karst limestone ridge at elev. 850-900 m a.s.l. Terrestrial herb 1-1.5 m on rocky slope. Flowers: tepals white, central petal deep purple, apex yellow with red-purple stripes. Common.