Marginal wood fern, dryoptère à sores marginaux

Polypodium marginale Linnaeus, Sp. Pl. 2: 1091. 1753

Leaves monomorphic, green through winter, 30--100 × 10--25 cm. Petiole 1/4--1/3 length of leaf, scaly at base; scales in dense tuft, pale tawny. Blade bluish green, ovate-lanceolate, pinnate-pinnatifid to 2-pinnate at base, leathery, not glandular. Pinnae ± in plane of blade, lanceolate; basal pinnae lanceolate, slightly reduced, basal pinnules longer than adjacent pinnules, basal basiscopic pinnule longer than basal acroscopic pinnule; pinnule margins shallowly crenate to nearly entire. Sori near margin of segments. Indusia lacking glands. 2 n = 82.

Rocky, wooded slopes and ravines, edges of woods, stream banks and roadbanks, and rock walls; 50--1500 m; Greenland; N.B., Nfld, N.S., Ont., Que.; Ala., Ark., Conn., Del., Ga., Ill., Ind., Iowa, Kans., Ky., Maine, Md., Mass., Mich., Miss., Mo., N.H., N.J., N.Y., N.C., Ohio, Okla., Pa., R.I., S.C., Tenn., Vt., Va., W.Va., Wis.

Dryopteris marginalis is an eastern North America endemic. Even though this species hybridizes with 10 other species, and some of these hybrids are fairly common, D . marginalis is not known to be involved in the formation of any fertile polyploid. Hybrids can be detected by malformed spores and the nearly marginal sorus position.