Botrychium simplex

Small Grape Fern

Small Grape Fern
Photo courtesy Wisconsin State Herbarium and Andrew Meeks

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

Name:

• Botrychium, from the Greek botrus (botrys), "grape"; the Grape Ferns
• simplex, from the Latin, "simple, undivided, unbranched"
• Common Name, from its size relative to the other Grape Ferns
• Other common names include Little Grape Fern, Dwarf Grape Fern, Least Moonwort, Yosemite Moonwort, Botryche simple (Qué), Pikkunoidanlukko (Fin), Dvärglåsbräken (Swe), Dvergmarinøkkel (Nor), Enkelt Månerude (Dan), Einfache Mondraute, Einfacher Rautenfarn (Ger)

Taxonomy:

• 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: 17190
• Also known as Botrychium tenebrosum
• Twelve species of Grape Fern (Botrychium spp.) occur in Canoe Country, all but Rattlesnake Fern (Botrychium virginianum) being rare or extremely rare. These are woodland jewels, rarely seen.

Description:

• A very small and highly variable grape fern, growing 2¾"-5½" tall. Individuals tend to be inconspicuous and scattered.
• Sterile Frond a single leaf pale green, smooth and fleshy, about 1½" long, simply compound, and close to stem; often clasping. Position on leaf stalk variable.
• Fertile frond rises above leaf as a single, unbranched stalk with prominent spore cases.
• Stem pale green, slender, succulent, and fragile; about ¾" long
• Rootstalk small, upright.
  • Roots few; smooth, fleshy, and spreading; about 2" below the surface.
• Our typical Botrychium simplex has a common woodland and swamp shade form that appears to be a persistent juvenile.

Identification:

• Identifiable as a Grape Fern by its diminutive size, succulent stem, and single leaf.
• Highly variable; absolutely distinguished from other small Grape Ferns only by its larger spores (0.035mm - 0.050mm), something not easily done in the field. However, in our area, the combination of very small size, unbranched fertile frond, and clasping, simply compound leaf (undivided lobes) strongly suggests this species.
• Field Marks
  • diminutive size
  • succulent stem
  • single compound leaf, often clasping
  • unbranched fertile frond

Distribution:

• Ontario to Newfoundland, south to Iowa, Illinois, Indiana, Ohio, and North Carolina. In the West, British Columbia to Alberta, south to California, Nevada, Utah, and Colorado.
• Also Europe.

Habitat:

• Dry fields, marshes, bogs, swamps, roadside ditches

Fire:

Associates:

History:

Uses:

Reproduction:

• Reproduces by spores

Propagation:

• By spores (difficult)

Cultivation:

• Hardy to USDA Zone 3 (average minimum annual temperature -40ºF)
• Not generally cultivated

Links:

• Den Virtuella Floran, Naturhistoriska riksmuseet, Stockholm

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