N. Vietnam, prov. Cao Bang, distr. Tra Linh, municipality Luu Ngoc, vicinities of Lung Mu village (N 22°47′ E 106°18′), about 14 km from Cao Bang town to the N. Secondary evergreen broadleaved closed forest on steep slopes and bluffs of remnant limestone ridge at 650-800 m alt. Epilite herb on shadow rocks. Leaves below violet. Not common.
CBL 1206 13 Dec. 1998
International Botanical Expedition of the U.S.A. National Geographic Society (grant No 6300-98)
Collectors: N.T.Hiep, N.Q.Binh, P.K.Loc, N.X.Tam, Averyanov L.