N. Vietnam, prov. Cao Bang, distr. Thach An, municipality Thuy Hung, vicinities of Na Lit village (N 22°30′ E 106°27′), about 27 km to SE from Cao Bang town. Secondary closed evergreen broadleaved forest between remnant limestone ridges on alluvial valley along stream at about 100 m alt. Terrestrial erect and climbing herb up to 3 m hg in open place. Flowers dull violet. Commonest very aggressive weed all over the area.
CBL 870 04 Dec. 1998
International Botanical Expedition of the U.S.A. National Geographic Society (grant No 6300-98)