N. Vietnam, Prov. Cao Bang, Distr. Tra Linh, Subdistr. Quoc Toan, evergreen forest on slopes of remnant limestone mountains near Thang Heng lake in environs of Thang Hen and Lung Tao villages at 600-700 m alt.
Epilite on limestone open rocks at 600-650 m alt. Flowers light green. Not common.
VH 2462 04.01.1996
International Botanical Expedition of the U.S.A. National Geographic Society (grant No 5094-93)
Participants: L. Averyanov, N.T. Ban, A. Budantzev, L. Budantzev, N.T. Hiep, D.D. Huyen, P.K. Loc, G. Yakovlev