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. Herb or shrublet up to 1.5 m hg on open wet rocks. Flowers blue-violet with whitish tepal tips. Not common.
CBL 652 25 Nov. 1998
International Botanical Expedition of the U.S.A. National Geographic Society (grant No 6300-98)