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Montana Field Guide

Montana Field Guides

Variegated Horsetail - Equisetum variegatum

Native Species

Global Rank: G5
State Rank: S4

Agency Status
MNPS Threat Rank:
C-value: 5

External Links

General Description
Stems monomorphic with 3 to 12 ridges, evergreen, 6–30 cm × 1–3 mm, branched at the base, erect or ascending. Sheaths green with a terminal black band, teeth white with a black center and hair-like tip. Strobili 5–10 mm long with a sharp-pointed tip, maturing in summer. Our plants are subspecies variegatum (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Diagnostic Characteristics
Stems evergreen, stomata borne in lines, 2 to each furrow. Stems with a central cavity and 5 or more vallecular cavities. Stems 5-12 ridged, teeth of sheaths persistant.

Species Range

Range Comments
Western MT with disjunct occurrences in Phillips and Garfield counties; circumpolar south to OR, UT, IL and NY (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Observations in Montana Natural Heritage Program Database
Number of Observations: 23

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density



(Observations spanning multiple months or years are excluded from time charts)

Wet, often calcareous, gravelly soil along seeps, streams, lakes at all elevations (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

  • Additional ReferencesLegend:   View Online Publication
    Do you know of a citation we're missing?
    • Bissell, J.K. & C.W. Bier. 1987 Dec 30. Presque Isle State Park: Botanical Survey and Natural Community Classification. U87BIS02.
    • Cobb, B. 1963. A Field Guide to the Ferns. Houghton Mifflin Company, Boston, USA. B63COB01PAUS
    • Fernald, M. L. 1950. Gray's manual of botany. Eighth edition. A handbook of the flowering plants and ferns of the central and northeastern United States and Adjacent Canada. American Book Co., New York.
    • Gleason, H.A. 1952. New Britton & Brown. Illustrated Flora. Lancaster Press Inc. Lancaster, Pa. B52GLE01PAUS
    • Hauke, R.L. 1963. A taxonomic Monograph of the Genus Equisetum Subgenus Hippochaete. C.B. Stuttgart. Weinheim GER. B63HAU01PAUS
    • Hauke, R.L. 1983. Horsetails (Equisetums) in North America. Fiddlehead Forum 10:39-43. A83HAU01PAUS
    • Lellinger, D.B. 1985. A Field Manual of the Ferns and Fern-Allies of the United States and Canada. Smithsonian Inst. Press. Washington, D.C. B85LEL01PAUS
    • Lesica, P., M.T. Lavin, and P.F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
    • Montgomery, J.O. 1981. Equisetum variegatum and Equisetum x trachydon. American Fern Journal 71:1-2. A81MON01PAUS
    • Schaffner, J.H. 1921. North American species of Equisetum North of Mexico. American Fern Journal 11:65-75. A21SCH01PAUS
    • Wherry, E.T. 1940-1941. The Ferns and Lycosphenes of Pennsylvania. Bartonia 21:11-37. A40WHE01PAUS
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Citation for data on this website:
Variegated Horsetail — Equisetum variegatum.  Montana Field Guide.  .  Retrieved on , from