FLORA OF VIETNAM. Pellionia macroceras Gagnep. N. Vietnam, Prov. Cao Bang, distr. Tra Linh, municipalite Quoc Toan,. vicinity of Thang Heng and Lung Tao villages near Thang Heng lake. Closed evergreen broadleaved primary forest on steep slopes and bluffs. of limestone ridges and mesas at 600-650 m alt. Terrestrial and epilitic herb on rocky steep shadow slopes. Common. No VH 4949  25-27.05.1997. International Botanical Expedition of the U.S.A. National Geographic. Society (grant No 5803-96). . Collectors: L. Averyanov, N.T. Hiep