Northern Vietnam, Ha Tinh Prov., Huong Son Distr., Son Kim Municipality, in the vicinity of Rao An village, around point 18°24′30′'N, 105°13′13′'E. Remnants of primary evergreen lowland seasonal broad-leaved forest on very steep granite/shale slopes of rocky river canyon at 180-200 m a.s.l. Terrestrial herb up to 0.3 m hg in shady place. Flowers pink-purple. Leaves above deep uniform green, below uniform light green with green nerves. Not common.