Houphan Prov., Hem Distr., Khon Ngua village, around point 19°55'53.2''N 103°16'24.2''E. Secondary broad-leaved evergreen open dry forest with bamboo on very steep rocky mountain slopes composed by solid marble like highly eroded limestone at elev. 700-950 m a.s.l. Shrub about 4 m tall on steep rocky slope. Flowers white. Common.