N. Vietnam, Prov. Thai Nguyen, distr. Dai Tu, vicinities of Tam Dao town, NE macroslope of Tam Dao ridge at 950-1000 m alt. (N 21°27′ E 105°38′). Closed wet evergreen broad-leaved primary forest on very steep mt slope. Terrestrial herb on rocky steep shadow slopes. Flowers black with dirty yellow tops of tepals. Very common. VH 5036 31.05.1997 International Botanical Expedition of the U.S.A. National Geographic Society (grant No 5803-96)