by Nathaniel Lord Britton & Addison Brown

“ Rootstock slender, widely creeping, the leaves few and distant. Stipes 6′–9′ long, slender; blades broadly deltoid-ovate, 3-4-pinnate, about 4′–6′ long and broad, the basal pinnae much the largest, unequally deltoidovate, their inferior pinnules 1′–2′ long; pinnules deeply divided into oblong or ovateoblong lobes, these deeply toothed or again pinnate; sori numerous; indusia ovate, deeply convex, delicate, very early thrust back and concealed or evanescent.
On rocks, Labrador and Quebec to British Columbia and Alaska, south to the northern shore of Lake Superior. ”

“ Coarse and usually rigid erect ferns of harsh texture, with pinnatifid to quadripinnatifid leaves borne typically in a crown upon a suberect or decumbent rootstock, the stipe not jointed to it. Sterile and fertile leaves similar, the vascular parts usually chaffy ”

“ Leaves equal, spreading, in a complete crown; stipes 1⁄2°–11⁄2° long, with dark brownish often darker-centered scales; blades 3⁄4°–23⁄4° 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 ”

“ Rootstock slender, creeping, blackish. Leaves long-stipitate, the blades lanceolate or oblong-lanceolate, scarcely narrowed at base, 1°-21⁄2° long, 4'-6' wide, short-acuminate, membranous, once pinnate; pinnae 11⁄2'-3' long, linear-lanceolate, short-stalked or sessile, horizontal or decurved, broadest at the base, shortacuminate, pubescent or pilose beneath, deeply pinnatifid; segments oblong, obtuse or appearing acute from the strongly revolute margins; veins regularly once or twice forked; sori nearly medial, crowded; indusia small, glabrous. ”

“ Indusium membranous, hood-like, attached by a broad base on its inner side and partly under the sorus, early thrust back by the expanding sporanges and at least partly concealed by them, withering, the sori thus appearing naked with age. Veins free.
About 10 species mainly natives of temperate regions; the following in North America. Type species: Polypodium bulbiferum L.
•Blades lanceolate, broadly lanceolate, or narrowly deltoid-lanceolate, 2-3-pinnate. •Blades broadest at base, long-tapering, bearing bulblets beneath.style="vertical-align:bottom; text-align:right ”

“ In rocky woods, Nova Scotia to Alaska, to northern New England, the mountains of Pennsylvania, to Michigan and British Columbia. Ascends to 5000 ft. in Vermont. Aug.
7.0
7. Dryópteris Adans. Fam. Pl. 2: 20, 550. 1763.
[Aspidium Sw. Schrad. Journ. Bot. 18002: 29, in part. 1801.] .
Mainly woodland ferns, commonly of upright habit, the fertile and sterile leaves usually similar, not jointed to the rootstock. Blades 1-3-pinnate or dissected, with veins free in northern species, uniting occasionally or even freely in some of the southern. ”

“ Rootstock stout, short, chaffy ; leaves clustered, the fertile ones surpassing the sterile. Stipes 2'-6' long, chaffy below, those of the sterile leaves slender, greenish and of the fertile stouter and stramineous; blades ovate or ovate-lanceolate, thin, glabrous, 2-3-pinnate, the sterile ones with the ultimate segments and pinnules crowded, ovate, oblong or obovate, obtuse, crenate or incised ; fertile blades with segments 3"-6" long, 1" or less wide, the thin margins involute to the midrib at first, at maturity expanded, exposing the sporanges. ”

“ A single species, O. sensibilis L.
1. Onoclea sensíbilis L.
Sensitive Fern. Fig. 21. Onoclea sensibilis L. Sp. Pl. 1062. 1753.
Rootstock rather slender, copiously rooting. Fertile leaves 1°–21⁄2° high. persistent over winter, the fertile portion bipinnate, much contracted, the short pinnules rolled up into closed berry-like bodies and forming a narrow close panicle. Sterile leaves 1°–41⁄2° high, the blades broadly triangular, deeply pinnatifid, the rachis winged; pinnae lanceolate-oblong, entire, undulate, or the lower and sometimes the middle ones sinuate-pinnatifid ”

“ Alpine Woodsia. Fig. 24. Acrostichum alpinum Bolton, Fil. Brit. 76. 1790.
Acrostichum hyperboreum Liljeb. Kgl. Vetensk. Akad. Nya Handl. 14: 201. 1793.
Woodsia hyperborea R. Br. Prodr. Fl. Nov. Holl. 1: 158. ”