Vietnam, Thua Thien – Hue Prov., A Luoi Distr., Huong Nguyen Municipality, about 8 km to the N of Tra Ve forest protection station, around point 16°17'17''N, 107°26'40''E at elevation about 240 m a.s.l. Secondary closed evergreen broad-leaved forest on steep hill and mountain slopes composed with shale along stream valley. Lithophyte on vertical shady cliffs along deep narrow stream canyon. Flower buds white. Locally abundant.