N. Vietnam, Lang Son prov., Huu Lung distr., Huu Lien municipality (N 21°40′ E 106°22′). Primary dry evergreen broadleaved forest along tops of remnant karst limestone ridge at elev. 270 m a.s.l. Shrub up to 3 m hg on open rocks. Flowers violet-lilac. Very common. Usual codominanthe of shrub forest stratum on mt tops.
NTH 3269 02 Oct. 1999
Collectors: N.T. Hiep, N.Q. Binh, L. Averyanov, P. Cribb.