Aspidium microchlamys H. Christ, Bull. Herb. Boissier 7: 820. 1899

Stems erect. Leaves arching, 3--8 dm; bulblets absent. Petiole 1/8--1/4 length of leaf, densely scaly; scales brown, diminishing in size distally. Blade broadly lanceolate, 1-pinnate-pinnatifid, base slightly narrowed. Pinnae narrowly lanceolate, not overlapping, in 1 plane, 3--13 cm; base oblique, proximal acroscopic segments enlarged; margins incised to costa but segments sessile and adnate to costa for at least 2 mm, segments excised and decurrent, serrulate-spiny with teeth spreading to ascending; apex acute with subapical and apical teeth same size; microscales filiform, dense abaxially, sparse adaxially. Indusia erose-dentate. Spore color unknown.

Terrestrial; 0--100 m; Alaska; Asia in Kamtchatka and Japan.

Polystichum microchlamys is found in the flora only on Attu, at the western tip of the Aleutian Archipelago.