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 fern on shadow wet steep rocky slopes. Not rare. VH 5018 31.05.1997 International Botanical Expedition of the U.S.A. National Geographic Society (grant No 5803-96)