Equisetum praealtum, the scouringrush horsetail, is a species of Equisetum (horsetail) native to North America and northeastern Asia. It was formerly widely treated as a subspecies or variety of the European and west Asian species Equisetum hyemale (rough horsetail), and still is by some authorities.
It is an evergreen herbaceous perennial plant, with green stems, each stem usually topped by a spore-bearing strobilus. The stems, produced in late spring and dying down a year and a half or two years later, are (occasionally to ) tall and diameter, usually unbranched; they are ridged, with 14âÂÂ50 ridges, and bear whorls of blackish bracts. The young stems are produced in spring and develop an apical spore-bearing strobilus in summer; sometimes, in the second year, the stem will produce a few side branches tipped with further strobili. It also spreads by means of rhizomes, which form clonal colonies.
It is found in wet places, including roadside ditches, along rivers, lake shores, and in wet woods.