FLORA OF VIETNAM. Elatostema collanieae Gagnep. N. Vietnam, Prov. Cao Bang, distr. Tra Linh, municipalite Quoc Toan,. vicinity of Thang Heng and Lung Tao villages near Thang Heng lake. Remnant closed evergreen primary broadleaved forest in alluvial valley. bottom between limestone ridges and mesas near karst lake at 500 m alt. Terrestrial and epilitic herb on shadow rocky wet lake slopes. Very. common at 500-600 m alt. No VH 4855  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