Polypodium virginianum L.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Rhizome 1.5–3 mm thick, the scales 2.5–5 mm, basally cordate, apically filiform-attenuate, entire, concolorous, light brown; lvs 8–40 cm, the petiole mostly 3–15 cm, scaly only at the very base; blade narrowly oblong, mostly 3–6 cm wide, narrowed to an acuminate tip, the rachis sparsely scaly beneath; segments mostly 12–20 pairs, 3–7 mm wide, slightly denticulate, apically obtuse, glabrous; veins evident, free, mostly twice-forked, terminating in hydathodes; sori superficial, borne close to the midvein of the segments, the sporangia intermingled with long glandular golden hairs; 2n=74, 111, 148. On rocks and banks in circumneutral soil, or seldom on tree-trunks; Nf. to Yukon, s. to Ga., Ala., Ark., and S.D. Perhaps equally well treated as var. virginianum (L.) D. C. Eaton of a broadly defined, circumboreal P. vulgare L.