N.Vietnam, Thanh Hoa Prov., Ba Thuoc Distr., Co Lung Municipality, Khuyn village, around point 20o26′50′'N, 105o14′37′'E. Primary evergreen seasonal broad-leaved lowland forest on crystalline marble-like highly eroded limestone, steep rocky slope of limestone ridge at elev. 50-100 m. Herb or semishrub up to 1,5 m hg in open place. Flowers white. Occasional.