Vietnam, Quang Binh Prov., Minh Hoa Distr., Dan Hoa municipality, Vietnam-Laotian border, about 3 km to S of Bai Dinh village, around point 17°44′46″N 105°46′28″E.
Primary and secondary broad-leaved evergreen forest on very steep slopes and on tops on remnant hills composed with highly eroded solid crystalline marble-like gray limestone at elevation 350-450 m a.s.l.
Lithophytic herb on shady wet mossy rocks. Leaves dark uniform green, flower buds pinkish-red. Common.
HAL 11843 23 April 2008 Coll.: L.Averyanov, P.K.Loc, N.T.Vinh, N.S.Khang