Marginalis means margined, referring to the position of the sori.
Rhizome: erect, soft, brown, chaffy scales.
Frond: 70 cm high by 20 cm wide, evergreen, monomorphic, blade/stipe ratio: 2:1 to 3:1.
Stipe: grooved, reddish brown at swollen base, becoming brownish green above, scaly at base; scales in dense tuft, pale tawny, vascular bundles: 7 in a c-shaped arc, sometimes fewer at the stipe apex.
Blade: 2-pinnate, ovate-lanceolate, leathery, deep green to felty blue-green, linear to ovate scales below, absent above.
Pinnae: 12 to 16 pair, in plane of blade, lanceolate; basal pinnae slightly reduced; pinnules basal pinnules longer than adjacent pinnules, basal basiscopic pinnule longer than basal acroscopic pinnule; costae grooved above, continuous from rachis to costae; margins shallowly crenate to nearly entire; veins free, forked.
Sori: round, in 1 row near the margin on the top two-thirds of the blade, indusium: reniform, silvery, attached at a sinus, sporangia: lead gray, then maturing to dark brown, maturity: midsummer.
Habitat: rocky, wooded slopes and ravines, edges of woods, stream banks and roadbanks, and rock walls .
Distribution: eastern North America, southern tip of Greenland.
Hardy to -40°C, USDA Zone 2.
sori neatly arranged along the margins
Polypodium marginale L.
Aspidium filix-mas var. marginale Chr.
Filix-Mas marginalis Farwell
Lastrea marginalis Presl
Nephrodium marginale Michx.
Polystichum marginale Keys.
Thelypteris marginalis Nieuwl.
Illustration from The Cultivated Species of the Fern Genus Dryopteris in the United States, Barbara Joe Hoshizaki and Kenneth A. Wilson, American Fern Journal, 89, 1, (1999), with permission.