N. Vietnam, Prov. Cao Bang, distr. Tra Linh, municipalite Quoc Toan, vicinity of Thang Heng and Lung Tao villages near Thang Heng lake. Broadleaved evergreen closed primary forest on steep slopes and bluffs of limestone mesas and ridges at 500-650 m alt. Tree up to 12 m hg. Not rare. Usual codominante in 1 forest stratum on and near tops of ridges and mesas at 700-1000 m alt. VH 4871 25-27.05.1997 International Botanical Expedition of the U.S.A. National Geographic Society (grant No 5803-96)