N. Vietnam, prov. Cao Bang, distr. Ha Lang, municipality Dong Loan, vicinities of Ban Lung and Lung Phuc (N 22°46′ E 106°44′), about 50 km to E from Cao Bang town. Open primary evergreen broadleaved closed
forest on steep slopes and cliffs of limestone ridge at 500-600 m alt. Shrublet up to 1 m hg in shadow canyon. Flowers dirty violet. Not common.
CBL 616 25 Nov. 1998
International Botanical Expedition of the U.S.A. National Geographic