Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east across northern North America to New England and the Canadian Maritimes; circumboreal.
Habitat: Cliff crevices, especially on limestone, often near or above timberline.
Conservation Status: Not of concern
Perennial from fibrous roots not proliferous; stems short-creeping to ascending, often branched; scales completely blackish to dark reddish brown, narrowly deltate, 2-4 mm long and 0.2-0.4 mm broad, margins entire or undulate or widely spaced shallow teeth.
Leaves monomorphic; petiole reddish brown at base and green distally, somewhat shiny, 1-5 cm, 1/4 to 1/2 length of blade, covered with dark reddish brown to black narrowly deltate scales transitioning into glandular hairs; blade linear, 1-pinnate, 2-13 cm long and 0.6-1.2 cm broad, thin, sparsely covered with minute hairs or not, base tapering slightly or truncate, apex acute, not rooting; rachis completely green and dull, mostly glabrous; pinnae in 6-21 pairs, deltate to rhombic, medial pinnae 5-6 mm long and 4-5 mm broad, base obtuse and frequently inequilateral, distal margins crenate, apex rounded to acute.
Sori in 2-4 pairs per pinna; spores 64 per sporangium.