Botrychium virginianum

Rattlesnake Fern

Rattlesnake Fern, Photo Courtesy USDA Plants Database
Rattlesnake Fern
Photo Courtesy USDA Plants Database

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


  • Botyrichium, from the Greek botrus (botrys), "grape"; the Grape Ferns
  • virginianum, from the Latin, "of Virginia". Like many North American species, it was named for the place where it was first identified.
  • Rattlesnake Fern, from the resemblance of the clustered sporangia to a snake's rattle.
  • Other common names include Virginia Grape Fern, Masasizikwa (Abenaki), Botryche de Virginie (Qué), Lehtonoidanlukko (Fin), Stor Låsbräken, Hundlokelåsbräken (Swe), Stormarinøkkel (Nor), Virginische Mondraute (Ger), Virginiai Holdruta (Hun)


    • Kingdom Plantae, the Plants
    • Division Polypodiophyta, the True Ferns
      • Class Filicopsida
        • Order Ophioglossales
          • Family Ophioglossaceae, the Adder's Tongue or Succulent Ferns
            • Genus Botrychium, the Grape Ferns
  • Taxonomic Serial Number: 17173
  • Twelve species of Grape Fern (Botrychium spp.) occur in Canoe Country, all but Rattlesnake Fern being rare or extremely rare.


  • Largest and most common Grape Fern in our area, 12"-18" tall.
  • Sterile Frond a single leaf bright green, membranous, and lacy; large and broadly triangular, 10" long and 12" wide, divided into leaflets on short stems.
    • Petiole (leaf stalk) erect, smooth, succulent, and round; 12" long; pink at base.
    • Pinnae (leaflets) oblong, cut, and toothed.
  • Fertile frond arising from base of leaf on slender 12" stalk, branched, bearing many spherical, bright yellow spore cases. Appears early summer and soon withers.
  • Rootstock small, upright.
    • Roots stout, fleshy, and tangled; branching and spreading, 2" or deeper, with numerous vertical, bud-like appendages.


  • Recognized as a Grape Fern by its large, single leaf and, in early summer, the single fertile stem arching above it.
  • Distinguished from other northern Grape Ferns by its much larger size and the lacy, thin textured, non-leathery leaf.
  • Field Marks
    • Single leaf paired (in season) with single fertile frond
    • Broad, lacy, triangular leaf


  • Labrador to British Columbia; south to Florida and Mexico. Also Eurasia.


  • Rich woods, moist or dry; moist thickets, higher spots in bogs.
  • Acid soils.
  • Shaded areas; soon disappears from sunny locations.






  • Reproduces by spores


  • By spore (difficult)


  • Hardy to USDA Zone 2 (average minimum annual temperature -50ºF)
  • Cultural Requirements
    • Must have shade
    • Prefers rich, moist woodland soils
  • A difficult plant for the garden
  • Occasionally available by mail order from specialty suppliers



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Last Updated on 26 February, 2004