Polypodium virginianum

Common Polypody

Polypodium virginiana, Rock Fern
Common Polypody
Boulder Lake, BWCAW
Photo © by Earl J.S. Rook

Flora, fauna, earth, and sky...
The natural history of the northwoods


  • Polypodium, from the Greek, polus (polus), "many", podos (podos), "foot"; "many footed"
  • virginianum, from the Latin, "of Virginia"
  • Common Name, from the generic name
  • Other common names include Rock Polypody, Rock Cap Fern, Polypode de Virginie, Tripes-de-roches (Qué), Senikaladabagw (Abenaki), Ezodenda (Jpn)


  • Kingdom Plantae, the Plants
    • Division Polypodiophyta, the True Ferns
      • Class Filicopsida
        • Order Polypodiales
          • Family Polypodiaceae, the Polypod Ferns
            • Genus Polypodium, the Polypod Ferns
  • Taxonomic Serial Number: 17242
  • Also known as Polypodium vulgare, Polypodium vulgare var. virginianum


  • A small evergreen fern of rock crevices, 4"-12"
  • Fronds spreading, compound with 10-20 alternate leaflets; lance-shaped; square base, pointed tip; 2"-10" long and 1¼"-2½" wide.
  • Stem ungrooved; scattered, with thin light-brown scales or smooth
  • Root System
  • Fruiting structure: Large dot-like reddish-brown spore clusters in 2 rows on underside of leaves.
  • Stems often whitish pruinose, slender, to 6 mm diam., acrid-tasting; scales weakly bicolored, lanceolate, contorted distally, base and margins light brown, sometimes with dark central stripe, margins denticulate.
  • Leaves to 40 cm.
  • Petiole slender, to 2 mm diam.
  • Blade oblong to narrowly lanceolate, pinnatifid, usually widest near middle, occasionally at or near base, to 7 cm wide, somewhat leathery;
  • rachis sparsely scaly to glabrescent abaxially, glabrous adaxially; scales lanceolate-ovate, usually more than 6 cells wide. Segments oblong, less than 8 mm wide; margins entire to crenulate; apex rounded to broadly acute; midrib glabrous adaxially. Venation free. Sori midway between margin and midrib to nearly marginal, less than 3 mm diam., circular when immature. Sporangiasters present, usually less than 40 per sorus, heads covered with glandular hairs. Spores more than 52 µm, tuberculate, surface projections more than 3 µm tall.


  • Identifiable as
  • Distinguished from
  • Field Marks


  • Alaska to Newfoundland, south to South Dakota, Arkansas, Alabama, and Georgia.


  • Rocks, boulders, cliffs, and ledges
  • Cliffs and rocky slopes; on a variety of substrates
  • Mats on dry rocky outcrops in deciduous and coniferous forests.
  • Rich woods and open woods; often on rocks or boulders



  • Mosses and lichen




  • Reproduces by spores and vegetatively by rhizomes


  • By rhizome division,


  • Hardy to USDA Zone 3 (average minimum annual temperature -40ºF)
  • Available by mail order from specialty suppliers



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Last Updated on 26 February, 2004