Siberian Polypody

Description

Rhizome: long-creeping, producing rows of fronds, occasionally branching, whitish pruinose, slender, to 6 mm diam., at the surface, scales lanceolate, brown, clathrate at the center.Frond: 25 cm high by 4 cm wide,evergreen, last year's fronds withering as this year's appear in early summer, monomorphic, blade/stipe ratio: 2:1 to 3:1.Stipe: jointed at base, straw-colored, glabrous or scattered with thin light-brown scales, vascular bundles: 3.Blade: pinnatifid, cut almost to the rachis, oblong-linear, usually widest at or near middle, leathery, rachis sparsely scaly below, glabrous above; scales lanceolate-ovate.Pinnae: 12 to 18 pair, oblong; margins entire to crenulate; apex rounded to broadly acute; veins free, forked, obscure.Sori: round, discrete, midway between margin and midrib to nearly marginal, at vein ends; on all but the lowest pinnae of fertile fronds, indusium: absent, sporangia: yellow to brown at maturity; non-glandular paraphyses (branching structures among the sporangia) present, maturity: summer-early fall.