Son La Prov., Yen Chau Distr., Muong Lum Municipality, Na Lang Village, around point 21°01′17″N 104°30′47″E.
Broad-leaved evergreen dry forest on steep slopes and on tops of ridge composed with rocky crystalline solid marble-like highly eroded limestone at elev. 900-1000 m a.s.l.
Terrestrial herb up to 1.5 m tall on open rocky slope. Flowers white. Common.
HAL 9472 03 Nov. 2006 Coll.: Nguyen Tien Hiep, L.Averyanov, Pham Van The.