Son La Prov., Van Ho Distr., Chieng Xuan Municipality, Co Hong village, territory of Xuan Nha natural reserve, Pha Luong Mountain.
Remnants of primary and secondary broad-leaved evergreen forest on very steep mountain slopes composed by brown sandstone at elevation 700-1000 m a.s.l. around point 20°42′14.2″N 104°43′53.9″E.
Woody vine 3-4 m long on rather open mossy slope. Flowers red, anthers yellow. Rare.