Appalachianum is the Latinization of Appalachian, describing a region of the Eastern US.
Rhizome: creeping, branching, whitish pruinose, slender, to 6 mm diam., scales lanceolate, mostly uniformly golden brown.
Frond: 35 cm high by 12 cm wide, evergreen, monomorphic, blade/stipe ratio: 1:1 or a little more.
Stipe: jointed at base, straw-colored, glabrous or scattered with thin light-brown scales, vascular bundles: 3.
Blade: pinnatifid, oblong to narrowly lanceolate, usually widest near the near base, leathery, rachis sparsely scaly below, glabrous above; scales lanceolate-ovate.
Pinnae: linear, entire to slightly dentate, broadest near the base, apex more pointed than virginicum, at least near the base of the the blade; veins free.
Sori: round, discrete, midway between margin and midrib to nearly marginal; on all but the lowest pinnae of fertile fronds, indusium: absent, sporangia: yellow then brown at maturity; paraphyses (branching structures among the sporangia) present, maturity: summer to fall.
Habitat: cliffs and rocky slopes; on a variety of substrates.
Distribution: eastern North America.
Hardy to -35°C, USDA Zone 3.
Distinguished from P. virginianum by being broader near the
base of the blade and stipe scales all golden brown, not bicolored. No
images of the scales could be found. Nonetheless, there is a good deal
of variation, and the taxonomist falls back on spore size and
Polypodium virginianum misapplied
with other species in the Eastern North America Group