Son La Prov., Moc Chau Distr., Chieng Son comm., Hin Pen village, around point 20°42’36.7N 104°35’11.0E. Primary and secondary evergreen broad-leaved forest on very steep slopes and cliffs of highly eroded red-brown sandstone at elevation about 1200 m a.s.l. Shrub 2 m tall in shady place on middle part of mountain slope. Flowers white. Not common.