Northern Vietnam, Ha Giang Prov., Quan Ba Distr., Can Ty Municipality, in the vicinity of Lung Vai village at left side of Mien River, around point 23°05′09′'N, 105°03′23′'E. Primary coniferous forest with Pseudotsuga brevifolia and Tsuga chinensis on remnant highly eroded limestone ridge at elev. 1440 m a.s.l. Woody vine 8-12 m lg. Flowers white, later yellowish. Not common.