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 700-750 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.
Terrestrial herb up to 1.2 m tall on open rocky wet slope. Flowers white, anthers light yellow. Very common.