N. Vietnam, Tuyen Quang prov., Na Hang distr., Thanh Tuong municipality, near Ban Bung village (22°16′26′'N, 105°25′58′'E). Primary broad-leaved evergreen very dry forest (with Burettiodendron hsienmu as a main dominant) near top of limestone ridge at elev. about 600 m a.s.l. Lithophyte fern on very steep rocky slope composed with slaty stratified limestone. Rare.