Son La Prov., Yen Chau Distr., Muong Lum Municipality, Na Hat village, around point 21°00′37″N 104°30′06″E.
Broad-leaved (and former coniferous forest with Calocedrus rupestris) evergreen forest on steep slopes and on tops of ridge composed with rocky crystalline solid marble-like highly eroded limestone at elev. 900 m a.s.l.
Terrestrial fern with fronds up to 2 m long on wet travertine slope in wet shady stream valley. Common.
HAL 9535 05 Nov. 2006 Coll.: Nguyen Tien Hiep, L.Averyanov, Pham Van The.