Phu Tho Prov., Tan Son Distr., Xuan Son Municipality, Du village, around point 21°02′55”N 104°56′51”E.
Primary broad-leaved forest on very steep rocky slopes and cliffs of Svoi Lap remnant mountain composed with highly eroded solid marble-like limestone at elevation 500-600 m a.s.l.
Terrestrial and lithophytic herb to 0.5 m tall on wet shady rocky slope. Locally very common.
HAL 12722 17 February 2009 Coll.: L.Averyanov, P.K.Loc, N.T.Vinh, L.T.Son.