Leaves monomorphic, green through winter, 32--90 × 10--20 cm. Petiole 1/3 length of leaf, scaly at least at base; scales scattered, tan. Blade green, ovate, 3-pinnate-pinnatifid, herbaceous, glandular. Pinnae ± in plane of blade, lanceolate-oblong; basal pinnae lanceolate, not reduced, basal pinnules longer than adjacent pinnules, basal basiscopic pinnule longer than basal acroscopic pinnule; pinnule margins serrate, teeth spiny. Sori midway between midvein and margin of segments. Indusia with minute glandular hairs. 2 n = 82. Moist rocky woods, especially hemlock hardwoods, ravines, and edges of swamps; 0--2000 m; N.B., Nfld., N.S., Ont., P.E.I., Que.; Ala., Conn., Del., Ga., Ill., Ind., Iowa, Ky., Maine, Md., Mass., Mich., Minn., Mo., N.H., N.J., N.Y., N.C., Ohio, Pa., R.I., Tenn., Vt., Va., W.Va., Wis. A related taxon, Dryopteris intermedia subsp. maderensis (J. Milde ex Alston) Fraser-Jenkins, occurs on eastern Atlantic islands.

Rhizome ±ascending or erect; lvs evergreen; petiole, rachis, costae, and indusia bearing minute stalked glands; petiole 1-3 dm, its broad, pale brown scales with an irregular darker area; blade 2-5 נ1-2 dm, broadest just above the obtuse base, abruptly tapered below the acuminate tip, bipinnate-pinnatifid to tripinnate-pinnatifid, the lowest pinnae usually with the lowest pair of pinnules shorter than the next pair, the lowest basal pinnule only slightly or not at all larger than the subopposite acroscopic one, the ultimate segments finely spinulose-toothed; sori midway between the midvein and the margins of the ultimate segments; 2n=82. Moist woods and swamps; Nf. to Ga., w. to Minn. and Ark. (D. austriaca var. i.; D. spinulosa var. i.)

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

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