Equisetum arvense is our most common species of horsetail. The stems are erect and usually bear many branches in whorls. There are conspicuous sheaths at the nodes, above the whorled branches, giving the stems a somewhat "jointed" appearance.

In our other species of Equisetum the spores are produced in a cone-like strobilus at the tip of the stem, but in Equisetum arvense the spores are produced by a separate fertile stem that is brown rather than green and is much shorter than the non-flowering green stems. Both fertile and sterile stems arise from wide-ranging, horizontal, underground stems called rhizomes. The rhizomes provide a means of rapid spread in much the same way that quack-grass spreads in gardens and Equisetum arvense can be an aggressive invader of sunny sites.