N. Vietnam, prov. Lao Cai, distr. Sa Pa, near Tram Tau village, N slope of Hoang Lien Son ridge at 1950-2000 m elev. (N 22°20′ E 103°50′). Secondary broadleaved evergreen wet forest with remnants of primary elements on shales. Shrub 1.5-2.5 m hg on open mossy wet rocks along stream. Marginal flowers white, central flower buds blue. Not rare.
NTH 2659 18 May 1999
International Botanical Expedition of the U.S.A. National Geographic Society (grant No 6300-98)