Scouringrush Horsetail (Equisetum hyemale var. affine)

Horsetail family (Equisetaceae)
Scouringrush Horsetail is an erect, evergreen, reed-like, perennial herb, reaching 5 feet tall and arising from creeping rhizomes. Its green stems are cylindrical, jointed, hollow, and usually unbranched and have rough longitudinal ridges that have silica deposits. At each joint, tiny leaves join together around the stem to create a narrow black-green band or sheath. It reproduces by means of spores from April to September and by vegetative reproduction. Found at the fertile stem’s tip, a dark, solitary, swollen, elliptical, spore-bearing cone releases the spores. Sterile stems look similar, but lack the cone. Found throughout much of the US and Canada. It occurs mainly along streams, and pond margins, in swamps, floodplains, woodlands, and ditches, on moist to wet soils or in shallow water. Prefers full sun to partial shade. Produces dense colonies and spreads aggressively. Historically used to scour floors and cooking pots and as a sandpaper. Has been used as a homeopathic remedy for hemorrhoid symptoms. Equisetum may be the oldest living genus of vascular plants with records as far back as 300 million years. Also known as scouring rush dutch rush, stout scouringrush, tall scouring rush, winter scouring rush, and rough horsetail.

Listed as Species of Special Concern in RI.