N. Vietnam, prov. Cao Bang, distr. Bao Lac, municipality Dinh Phung, Man Lung ridge (N 22°47′ E 105°49′). Primary wet broadleaved evergreen forest on steep slopes of remnant karst limestone Man Lung ridge at 1400-1500 m elev. Creeping terrestrial herb. Flowers greenish outside, dirty brownish inside. Not common.
CBL 1535 18 April 1999
International Botanical Expedition of the U.S.A. National Geographic Society (grant No 6300-98)