Houphan Prov., Viengxay Distr., Xieng Luong village, around point 20°22′06.1′'N 104°17′18.6′'E.
Primary and secondary broad-leaved evergreen dry forest on very steep rocky slopes of highly eroded mountains composed by solid marble-like limestone at elev. 600-700 m a.s.l.
Herbaceous vine 4-5 m long in alluvial valley between limestone mountains among open secondary scrub. Flowers pale pink-purple. Occasional.