This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol1", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
1801. Dryopteris spinulosa Kuntze, Rev. Gen. PI. 2: 813. 1891.
Rootstock stout, creeping, chaffy. Leaves in an incomplete crown, the taller erect, the others spreading; stipes 4'-14' long, with pale brownish scales; blades 1/2°-1 1/2° long, 3 1/2'-9' broad, ovate-lanceolate to oblong, acuminate, deeply 2-pinnatifid; pinnae usually oblique, pinnately divided, the lower ones unequally deltoid, those above lanceolate from a broad base, acuminate; pinnules flat, oblong to lanceolate, acute, decurrent, pinnately cut, segments incised, teeth mucronate, falcate, appressed; sori submarginal, terminal on veinlets; indusia without glands.
1830. Dryopteris spinulosa var. dilatata Underw. Nat. Ferns, ed.
4, 116. 1893.
Rootstock creeping, or ascending. Leaves equal, spreading, in a complete crown; stipes 1/2°-1 1/2° long, with dark brownish often darker-centered scales; blades 3/4°-2 3/4° long, 4'-16' broad, triangular to ovate or broadly oblong, acuminate, 3-pinnatifid; pinnae variable, the lower ones broadly and unequally ovate or triangular, those above lanceolate to oblong, acute or acuminate, the lowermost at least pinnately divided; pinnules convex, oblong to lanceolate, acute, the largest not decurrent, pinnately divided, segments pinnately lobed, teeth mucronate, straight or falcate, usually not appressed; sori mostly subterminal; indusia glabrous, or with a few glands.
A high mountain species of rocky woods, Newfoundland to Alaska, California, Idaho, Tennessee and North Carolina, Greenland. Also in Eurasia, Japan and the Madeira Islands. Broad Prickly-toothed Wood-fern.
Polypodium intermedium Muhl.; Willd. Sp. PI. 5: 262.
1810. Aspidium americanum Davenp. Am. Nat. 12: 714. 1878. Dryopteris spinulosa var. intermedia Underw. Nat. Ferns, ed. 4, 116. 1893.
Rootstock creeping. Leaves equal, spreading in a complete crown; stipes 4'-14' long, with light brownish or darker-centered scales; blades similar in size and shape to those of D. spinulosa, glandular-pubescent when young; pinnae usually at right angles to the rachis, the lower ones at least pinnate, unequally lanceolate to ovate-lanceolate; the upper ones lanceolate to oblong, acuminate; pinnules convex, oblong or lanceolate, acute, the largest not decurrent, pinnately divided, nearly at right angles; segments dentate, usually straight; sori sub-marginal, subterminal; indusia glandular.
In moist woods, Newfoundland to Wisconsin, south to North Carolina and Tennessee. Known only from eastern North America. Called also Common Wood-fern.