Canada

Field horsetail

Equisetum arvense

Perennial with a spreading rhizome system that produces numerous shoots and tubers, mainly occurs in moderate areas.

Upright, hollow, jointed, cylindrical stems with inconsequential and easily overlooked leaves.

Stems: Two types of stems: The fertile (reproductive) stems appear in the early spring and are whitish to light brown, unbranched, hollow, 8 mm (0.31 inch) in diameter, cylindrical, leafless, jointed, and 15-30 cm (5.9 - 11.8 inch) long with 8 to 12 teeth.
Sterile stems are green, erect or somewhat prostrate, 15-60 cm (5.9 - 23.62 inch) tall and are composed of slender, grooved, hollow joints, 1 to 1.5 mm (0.039 - 0.059 inch) in diameter .The middle and upper joints have 6 to 12 needle-like branches that are 5-10 cm (1.97 - 3.93 inch) long, jointed but not hollow, 3- or 4-angled with blackened tips. The stems and branches are surrounded by a small, toothed sheath at each node.

Leaves: Leaf sheaths of fertile shoots with ridged, rough textured 8-12 dirty brown teeth. Leaf sheats of sterile shoots triangular-lanceolate, half as long as sheath tube.