N.Vietnam, Cao Bang Prov., Trung Khanh Distr., Ngoc Khe Municipality, Pac Nga village, around point 22є54'59''N, 106є31'44''E, at elevation 700-750 m a.s.l. Secondary wet closed evergreen forest on steep rocky slopes of rocky ridges and mesae composed with light gray solid marble-like highly eroded crystalline limestone. Lithophytic herb on shady vertical cliffs. Common.