Distribution
United States of America

Native to: Alabama, Arizona, Arkansas, Cape Provinces, Colorado, Connecticut, Delaware, District of Columbia, Free State, Georgia, Illinois, Indiana, Iowa, Kansas, Kentucky, KwaZulu-Natal, Lesotho, Louisiana, Maine, Maryland, Masachusettes, Michigan, Minnesota, Mississippi, Missouri, Nebraska, New Hampshire, New Jersey, New Mexico, New York, North Carolina, Northern Provinces, Ohio, Oklahoma, Ontario, Pennsylvania, Québec, Rhode I., South Carolina, Tennessee, Texas, Vermont, Virginia, West Virginia, Wisconsin.

Roots not proliferous. Stems short-creeping, unbranched; scales dark brown to black throughout, narrowly linear-deltate, 2-4 × 0.3-0.6 mm, margins entire. Leaves ± dimorphic; fertile leaves taller and more erect than sterile leaves. Petiole reddish brown throughout, lustrous, 1-10 cm, 1/4-1/3 length of blade; indument of dark brown to black, filiform scales at base. Blade lustrous, linear to narrowly oblanceolate, 1-pinnate throughout, 4-50 × 2-5(-7) cm, thin, glabrous, or occasionally sparsely pubescent; base gradually tapered; apex acute, not rooting. Rachis reddish or purplish brown throughout, lustrous, glabrous. Pinnae in 15-45 pairs, oblong to quadrangular; medial pinnae 1-2.5 × 0.3-0.5 cm; base with conspicuous acroscopic and sometimes basiscopic auricle, this overlapping rachis; margins crenate to serrulate, sometimes more deeply incised in robust specimens; apex acute to obtuse. Veins free, evident. Sori 1-12 pairs per pinna, on both basiscopic and acroscopic sides. Spores 64 per sporangium. 2 n = 72.
Forest floor or on rocks, often invading masonry and disturbed soils; 0-1300 m.