Vietnam, Thua Thien – Hue Prov., Nam Dong Distr., Huong Son Municipality, around point 16°09′52′'N, 107°36′22′'E.
Heavily logged primary closed broad-leaved evergreen lowland forest along La Ma River on very steep hill slopes composed with clayey shale at elevation about 300-450 m a.s.l.
Woody vine 5-7 m long in open place. Flowers light blue-violet. Not rare.