Cao Bang Prov., Thong Nong Distr., Yen Son Municipality, Ngan Vai village, around point 22°46'53"N, 105°52'58.7"E.
Primary fractionaly logged coniferous forest with Pseudotsuga sinensis along highly eroded rocky limestone ridge at elevation about 1300 m a.s.l. Terrestrial and lithophytic herb to 0.5 m tall in shady places on middle part of mountain slope. Flowers white, or with greenishtint. Common.