Northern Vietnam, Ha Giang Prov., Quan Ba Distr., Thanh Van Municipality, in the vicinity of Lung Cung village, around 1 km to the E from point 23°05′32′'N, 105°00′10′'E. Primary coniferous forest with Pseudotsuga brevifolia on remnant highly eroded limestone ridge at elev. 900-1000 m a.s.l. Creeping woody vine 3-4 m lg on open mossy rocks. Flowers white with yellow tint. Not rare.