Distribution: Occurring east of the Cascades crest in northeastern Washington; Alaska to Idaho, east across northern U.S. and Canada to eastern North America; also in Europe.
Habitat: Moist woods and thickets at middle elevations in the mountains.
Conservation Status: Sensitive in Washington (WANHP)
Perennial with stems creeping to erect, lacking stolons.
Leaves dimorphic, 35-70 cm long and 8-12 cm broad; fertile leaves dying back each winter; sterile leaves several and small, forming rosette, evergreen; petiole 1/4-1/3 length of leaf; scales found at least at base, scattered, tan; blade green, narrow-lanceolate or with parallel sides, pinnate-pinnafitid, eglandular; pinnae of fertile leaves turned to nearly right angles to blade plane, deltate, basal pinnae deltate and slightly reduced, basal pinnules longer than others, basal basiscopic pinnule equal to basal acroscopic pinnule, pinnule margins distantly serrate with spiny teeth.
Sori halfway between midvein and segment margins; indusia glands absent, round-reniform, attached at narrow sinus; spores brownish.