Woodsia ilvensis

Rusty Woodsia

Rusty Woodsia, Jap Lake, BWCAW, Photo © 2001 by Earl J.S. Rook
Rusty Woodsia
Jap Lake, BWCAW
Photo © 2001 by Earl J.S. Rook

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


Name:

  • Woodsia, for English botanist Joseph Woods (1776-1864).
  • ilvensis, from the Latin name for the island of Elba, best known for its Napoleonic associations.
  • Common name from the abundant hair and scales borne by this species.
  • Other common names include Rusty Cliff Fern, Oblong Woodsia (UK), Woodsie de l'île d'Elbe (Qué), Hällebräken, Vanlig Hällebräken (Swe), Lodnebregne (Nor), Almindelig Frynsebregne (Dan), Karvakiviyrtti (Fin), Liðfætla (Is), Südlicher Wimperfarn (Ger), Északi Szirtipáfrány (Hun),

Taxonomy:

  • Kingdom Plantae, the Plants
    • Division Polypodiophyta, the True Ferns
      • Class Filicopsida
        • Order Polypodiales
          • Family Dryopteridaceae, the Wood Ferns
            • Genus Woodsia, the Cliff Ferns
  • Taxonomic Serial Number: 17741
  • Also known as Acrostichum ilvense

Description:

  • A small, coarse fern of rocky places and our most common Woodsia.
  • Fronds light green with silver/white undersides, turning rusty colored in fall and dry seasons. Greens up when rains return, yielding its other common name of Resurrection Fern.
    • Petiole (leaf stalk) usually brown or dark purple when mature, segmented above base at swollen node; relatively brittle and easily shattered.
    • Blade narrowly lanceolate, usually twice-cut toward the base, ½"-1½" × 1¾"-9¾"
    • Rachis (axis) green, usually with abundant hairs and scales.
    • Pinnae (primary leaflets) crudely triangular, longer than wide, abruptly tapered to a rounded or broadly pointed tip; largest pinnae typically subdivided into 7 pinnules; underside has mixture of hairs and linear-lanceolate scales while upper surface has hairs concentrated along midrib.
    • Pinnules (secondary leaflets) smooth edged or crinkled, rarely shallowly lobed; edges thin and ciliate with hairs. Vein tips frequently enlarged to form whitish hydathodes visible from above.
  • Rootstalk short, compact, erect, with abundant persistent petiole bases of more or less equal length; scales abundant, dark brown, toothed, and pointed.
    • Roots fine, lacy, and black, with many tiny rootlets.
    • Fiddleheads silver/white and visible throughout the growing season.
  • Sori small, round, in single row between midrib and margin on ultimate segments, with distinct indusium. Often hidden by the abundant hair and scales.

Identification:

  • Identifiable as Woodsia by
    • articulate bases to the petioles and the accumulation of petiole bases that have broken off below the articulation.
    • relatively small size for our area
    • affinity for rocky habitats
    • twice-cut fronds
  • Distinguished from
    • Smooth Woodsia (Woodsia glabella) by its hairs and scales
    • Alpine Woodsia (Woodsia alpina) by its abundant hairs and scales and the greater number of pinnules, 4-9 pairs on each pinna (leaflet).
    • Rocky Mountain Woodsia (Woodsia scopulina) and Oregon Woodsia (Woodsia oregana) by its articulated or segmented leaf stalk (petiole).
  • Field Marks
    • hairs and scales on fronds and leafstalks
    • presence or absence of stem segmentation or articulation
    • color of mature leaf stalk

Distribution:

  • Alaska to Newfoundland and Greenland, south to British Columbia, Alberta, Saskatchewan, Manitoba, Minnesota, Iowa, Illinois, Ohio,West Virginia, and North Carolina.
  • Also northern Eurasia.

Habitat:

  • Sunny, exposed cliffs and rocky slopes
  • Thin, dry, acidic soils on many different rock types.

Fire:

Associates:

History:

Uses:

Reproduction:

  • By spore

Propagation:

  • By spore; difficult.

Cultivation:

  • Hardy to USDA Zone 3 (average minimum annual temperature -40ºF)
  • Generally not available commercially.

Links:

Comments:

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Last Updated on 26 February, 2004