Equisetum laevigatum

Smooth Scouring Rush

Smooth Scouring Rush
Photo courtesy Wisconsin State Herbarium and Michael Clayton

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

Name:

• Equisetum, from the Latin, equus, "horse", and seta, "bristle, animal hair"
• laevigatum, from the Latin, "smooth, slippery"
• Common name from the surface texture relative to the other Scouring Rushes.
• Other common names include Smooth Horsetail, Bakushi, Kawasíola (Tarahumara), Naks r bhai Baapak (Tepehuán), Cola de caballo, Tuti (Mex)

Taxonomy:

• Kingdom Plantae, the Plants
  • Division Equisetophyta, the Horsetails
    • Class Equisetopsida, the Horsetails
      • Order Equisetales, the Horsetails
        • Family Equisetaceae, the Horsetails
          • Genus Equisetum, the Horsetails
• Taxonomic Serial Number: 17156
• Also known as Equisetum funstonii, Equisetum kansanum, Hippochaete laevigata

Description:

• Stem erect, green, annual, jointed, grooved with 10-32 ridges, smooth, usually unbranched, up to 5' tall.
• Leaf Sheath green, elongate, 7-15×3-9mm; leaves reduced to 10-32 tiny, black teeth with white borders, triangular scales encircling the stem at each joint, usually shed early, leaving dark rim on sheath.
• Cone up to 1" long, somewhat broader than stem, with rounded, blunt tip, capped with small, needle-like point.
• Spores green, spheric.

Identification:

• Identifiable as a Horsetail by the upright, hollow, jointed, cylindrical stems with inconsequential and easily overlooked leaves.
• Distinguished from similar, unbranched Horsetails (Scouring Rushes) by its smooth stems and needle-tipped cones
  • Common Scouring Rush (Equisetum hyemale), also known as Rough Scouring Rush or Rough Horsetail, has a rougher surface and distinctive, ashy grey bands at stem joints.
  • Variegated Scouring Rush (Equisetum variegatum), shows a distinct white margin at the stem joints, hence "variegated"
• Field Marks
  • nearly smooth stems
  • pointed cones

Distribution:

• British Columbia to Québec, south to Baja California, Northern Mexico, Texas, Arkansas, Missouri, Illinois, Indiana, and Ohio.

Habitat:

• Moist prairies, riverbanks, roadsides.
• Typically occurs in wetlands, but occasionally found in non-wetlands

Fire:

Associates:

History:

Uses:

Reproduction:

• By spore and vegetatively by rhizome

Propagation:

• By rhizome division

Cultivation:

• Hardy to USDA Zone 3 (average minimum annual temperature -40ºF)
• Cultural Requirements
• Sun to part shade
• Constantly moist
• Fertilization unnecessary
• Good for bog gardens, pond margins, and naturalizing low, wet areas.
• Can be invasive.
• Available by mail order from specialty suppliers.

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