Son La Prov., Moc Chau Distr., Chieng Son comm., Pha Luong village, Pha Luong Mountains.
Open secondary forest on foothills of highly eroded red-brown sandstone mountains at elevation 1200-1300 m a.s.l. around point 20°41′33.2N 104°37′37.0E.
Herbaceous vine 10 m long in open place. Very common, particularly in secondary open forests and shrubs.