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..
Mainly shade-loving species of various habit, commonly epiphytic in the humid tropics, the leaves articulate to the creeping or ascending rhizome at the base of the stipe, the blades ranging from simple to bipinnate or several times pinnatifid, the veins free. Sori round or less commonly oval or elliptical, dorsal or sometimes terminal on the veins. Indusia wanting. [Greek, probably in allusion to the numerous knob-like prominences of the rootstock.]
As here limited to free-veined species, the genus comprises several hundred species, mainly of tropical and subtropical regions. Several additional species occur in the southern and western United States. Type species: Polypodium viilgare L.
Lower surface of the blade densely scaly; plant grayish.
Polypodium vulgare L. Sp. PI. 1085. 1753.
Rootstock slender, widely creeping, densely-covered with cinnamon-colored scales. Stipes light colored, glabrous, 2'-6' long; blades ovate-oblong or narrowly oblong, subcoria-ceous or chartaceous, evergreen, glabrous, 3'-10' long, 1-3' wide, cut nearly to the rachis into entire or slightly toothed, obtuse or subacute, linear or linear-oblong segments; sori large, about midway between the midrib and margins of the segments, upon the anterior branch of the mostly 1-3-forked veins.
On rocks or rocky banks, occasionally on trees, Labrador and Newfoundland to Manitoba and Keewatin, south to Georgia. Alabama and Missouri. Ascends to 5600 ft. in Virginia. The blade varies much in cutting, and numerous forms have been described. One of these, the var. cambricum, is notable for its broad pin-natifid segments. Male polypody, golden locks, golden maiden's-hair. Adder's-, moss-, wood-, male-, sweet-fern; Rock- or Stone-brake.
Acrostichum polypodioides L. Sp. PI. 1068. 1753. P. incanum Sw. Fl. Ind. Occ. 3: 1645. 1806. Polypodium polypodioides A. S. Hitchcock, Rep. Mo. Bot. Gard. 4: 156. 1893.
Rootstock widely creeping, woody, covered with small brown scales. Stipes densely scaly, 1'-4' long; blades oblong-lanceolate, acute, coriaceous, evergreen, 1'-7' long, 1'-2' wide, cut very nearly or quite to the rachis into entire oblong or linear-oblong obtuse segments, glabrous or nearly so on the upper surface, the lower densely covered with gray peltate scales with darker centers, as also the rachises; veins indistinct, unconnected or casually joined.
On trees or less commonly on rocks, Pennsylvania to Florida, west to Iowa, Kansas and Texas. Widely distributed in tropical America. July-Sept. Called also Hoary-, Scaly-, Tree-Polypody; Rock-brake. Resurrection-fern.