N.Vietnam, Cao Bang Prov., Trung Khanh Distr., Ngoc Khe Municipality, Pac Nga village, around point 22°54'59''N, 106°31'44''E, at elevation 700-800 m a.s.l. Closed secondary and remnants of primary broad-leaved evergreen forest on very steep rocky slopes of rocky ridges and mesae composed with light gray solid marble-like highly eroded crystalline limestone. Tree 6-8 m tall on high part of slope. Flowers white. Not common.