Luang Prabang prov., Ngoy distr., Don Khun village, near waterfall, around point 20°31′36.9′'N 102°35′15.8′'E.
Remnants of primary evergreen forest on very steep rocky mountain slopes composed by solid marble like highly eroded limestone at elev. 450-550 m a.s.l. along mountain stream.
Herbaceous vine 3-4 m long in open secondary forest. Flowers white. Very common.