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′). Terrestrial herb in open grasslands among limestone rocks at about 500 m elev. Flowers whitish. Very common. Commonest weed in the area.
CBL 1597 21 April 1999
International Botanical Expedition of the U.S.A. National Geographic Society (grant No 6300-98)