Vietnam, Quang Binh Prov., Quang Ninh Distr., Truong Son municipality, around Chan Trong village at 17°10′49″N 106°29′22″E.
Secondary dry broad-leaved forest on tops and steep slopes of highly eroded karst limestone mountain composed with gray solid marble limestone allied to Long Dai River, at elevation 300-400 m a.s.l.
Lithophytic herb to 1 m tall on vertical cliff. Flowers light violet. Not common.
HAL 11543 13 April 2008 Coll.: L.Averyanov, P.K.Loc, N.T.Vinh, N.S.Khang