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. Terrestrial and epilitic herb or shrublet up to 1.5 m hg on wet rocky slopes. Leaves green above, deep purple below, strongly urticate. Very common, and often abundant in mt forests at 500-600 m alt. VH 4844 25-27.05.1997 International Botanical Expedition of the U.S.A. National Geographic Society (grant No 5803-96)