N. Vietnam, prov. Cao Bang, distr. Nguyen Binh, municipality Thai Hoc, about 5-6 km to ENE of Nguyen Binh town (N 22°39′ E 105°57′). Secondary open shrubs on steep slopes of karst remnant limestone mesae at 500-550 m elev. Terrestrial herb in wet place along road. Common. Commonest weed in the area.
CBL 1619 21 April 1999
International Botanical Expedition of the U.S.A. National Geographic Society (grant No 6300-98)