N. Vietnam, prov. Lai Chau, about 50 km downstream along Black river (Song Da), from Lai Chau town (N 22°03′ E 103°09′) to Nam Ma village (distr. Sin Ho). Open shale and limestone rocks on steep slopes of the river at elev. about 220 m. Prostrate forb up to 20 cm hg on open wet sandy place along river side. Flowers white-blue. Very common.
NTH 2731 24 May 1999
International Botanical Expedition of the U.S.A. National Geographic Society (grant No 6300-98)