Vascular Plants - Equisetaceae - Equisetum:
Equisetum arvense
Page Author: Don Knoke
field horsetail, common horsetail 
Habit: herb
Duration: perennial
Origin: Native
Distribution: Cosmopolitan; throughout the Pacific Northwest
Habitat: Moist to moderately dry areas
Species Description:

General: : Rhizomatous annual, the stems dimorphic; sterile stems 1.5-6 dm. tall and 1.5-5 mm. thick, prominently 10- to 12-ridged, the central cavity about 1/4 the diameter of the stem; stomates in 2 broad bands in the furrows; sheath 5-10 mm. long, greenish, with teeth 1-3 mm. long, free, firm and brown; fertile stems brownish to whitish, soon withering, simple, up to 3 dm. tall and 8 mm. thick, with sheaths 14-20 mm. long, and large teeth 5-9 mm. long.
Leaves: Branches only on sterile stems, whorled, ascending, 3- or 4-angled, solid, 1-1.5 mm. thick, sometimes again branched.
Spores: Cone 0.5-3.5 cm. long, long-pedunculate, blunt.
Accepted Name:
Equisetum arvense L.
Synonyms:
Equisetum arvense L. var. boreale Bongard

Treated in Flora of the PNW as:
Equisetum arvense
Additional Resources:

PNW Herbaria Specimens: View list of all Equisetum arvense specimens in the Consortium of Pacific Northwest Herbaria database.

WTU Herbarium Specimens: View list of Equisetum arvense specimens in the WTU Herbarium database.

Washington Flora Checklist: Equisetum arvense treatment.

E-Flora BC: Equisetum arvense atlas page.

CalPhotos: Equisetum arvense images.

USDA Plants Database: Equisetum arvense.
Additional photographs of Equisetum arvense:
(click on a thumbnail to view larger photo)

Ben Legler, 2004

Ben Legler, 2004

Ben Legler, 2004

Ben Legler, 2004

Ben Legler, 2004

Ben Legler, 2004

Bud Kovalchik

G. D. Carr, 1996

G. D. Carr, 1996

G. D. Carr, 1996

G. D. Carr, 1996

Sandie Durand, 2010

Sandie Durand, 2010

Sandie Durand, 2010

G. D. Carr, 2010

G. D. Carr, 2010

G. D. Carr, 2010

G. D. Carr, 2010

G. D. Carr, 2010

G. D. Carr, 2010

Robert L. Carr, 2010

Robert L. Carr, 2010

Susan McDougall, 2014

Susan McDougall, 2014

Roger T. George, 2016

Roger T. George, 2016
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Washington Native Plant Society
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