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 and lithophyte herb on wet open places. Flowers yellow. Very common. Commonest weed in the area.
CBL 1606 21 April 1999
International Botanical Expedition of the U.S.A. National Geographic Society (grant No 6300-98)