Contr. U.S. Natl. Herb. 17: 605. 1916.
Stem scales concolored to weakly bicolored, margins usually brown, very narrow and poorly defined, thin, ciliate-denticulate. Leaves 5–15 cm. Petiole brown, equal to or shorter than blade, rounded adaxially, glandular-farinose, bearing scattered hairs and scales. Blade linear-lanceolate, 2-pinnate-pinnatifid, 3–6 times longer than wide, abaxially with conspicuous cream-colored or pale-yellow farina and dull, light-brown, narrowly lanceolate, ciliate scales scattered along rachises and costae, adaxially sparsely glandular and villous with long, multicelled, whitish hairs; basal pinnae equal to or slightly larger than adjacent pair, ± equilateral, proximal basiscopic pinnules not greatly enlarged. Ultimate segments sessile, broadly adnate to costae; segment margins slightly recurved, rarely concealing sporangia. Sporangia containing 16 spores.
Phenology: Sporulating summer–fall.
Habitat: Rocky slopes and cliffs, usually on volcanic substrates
Elevation: 700–1200 m
Notholaena aliena is a rare species closely related to N. grayi. Preliminary studies indicate that N. aliena reproduces by apogamy and is probably triploid.