Asplenium pinnatifidum Muhl.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Rhizome 1 mm thick, its scales 4–6 mm; lvs spreading, 1–3 dm, the petiole to 12 cm, brown basally or throughout; blade firm, lance-linear, to 2.5 cm wide, deeply pinnatifid or pinnate at the base, merely lobed above, the caudate-attenuate tip wavy or entire; rachis green; pinnate or lobed to 7 pairs or more, the basal ones mostly subrotund to ovate, bluntly toothed; 2n=144, believed to be an alloploid from spp. 2 and 9. Crevices in noncalcareous rocks, and in acid soil; N.J. and Pa. to Ga., w. to Ill., Mo., and Okla.