Polypodium sibiricum Siplivinskij

Polypode de Sibérie, Multileg Siberian, Siberian polypod

Etymology of Siberia
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.
Culture Habitat: cracks and ledges on rock outcrops in boreal areas. Distribution: Greenland, northern Canada, Alaska, northern Asia. Hardy to zone 2, probably not in cultivation.
Distinctive Characteristics Similar to P. virginianum, to which it is a parent, but smaller, paraphyses lacking glands.
Polypodium virginianum misapplied
Polypodium sibiricum
Polypodium sibiricum with superimposed blow-up of sorus containing sporangia mixed with paraphyses (the white bundles); the rhizome scales are clathrate at the center  Flora of North America
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