Aquatic and Wetland Vascular Plants of the Northern Great Plains
1. Equisetaceae, the Horsetail Family
1. Equisetum L. -- Horsetail, scouring rush1. Equisetum arvense L. -- Common horsetail
Stems dimorphic, annual, erect or decumbent. Sterile stem green, regularly branched, 1-6 dm tall, mostly 10- or 12-ridged, the ridges usually roughened but lacking spicules of silica deposit; central cavity ca. 1/4 the stem diameter; main stem sheaths 5-10 mm long, the teeth free or partly fused, with long-acuminate tips, brown to blackish, 1.5-2 mm long. Branches numerous, simple, ascending to occasionally recurved, 3- or 4-angled; sheaths on the first internodes of the branches with 3 or 4 teeth. Fertile stem unbranched, brownish, to 2 dm tall, appearing in early spring (late Apr--early May) and soon withering; sheaths 10-20 mm long, the teeth of the lower sheaths dark brown to blackish, mostly separate with long, acuminate tips, 4-9 mm long. Cone terminal, blunt, long-stalked. Stream banks, meadows, ditches and moist woods; common; (Cosmopolitan).
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| Equisetum arvense, vegetative stem. The green vegetative stems are conspicuous throughout summer after the nongreen cone-bearing stems have withered. |
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Return to Family -- Equisetaceae - The Horsetail Family
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