Horsetail (Equisetum Hyemale) 10 Spores Scouring rush (also commonly called rough horsetail) is a non-flowering, rush-like, rhizomatous, evergreen perennial which typically grows 3-5 tall and is native to large portions of Eurasia, Canada and the U.S., including Missouri. It typically occurs in wet woods, moist hillsides and peripheries of water bodies (lakes, rivers, ponds). This species features rigid, rough, hollow, vertically-ridged, jointed-and-segmented, bamboo-like, dark green stems (to 1/2 diameter at the base) which rise up from the plant rhizomes. Each stem node (joint) is effectively marked by a whorl of tiny, stem-clasping, scale-like leaves which are fused into an ash-gray sheath (1/4 long) ending in a fringe of teeth. Teeth are usually shed during the growing season. Each sheath is set off and accentuated, both above and below, by thin, stem-ringing, black bands. Photosynthesis is basically carried on by the stems of this plant. Vegetative and fertile stems are alike in this species, with some vegetative stems bearing, at the stem tips, pine cone-like fruiting heads (to 1 long) which contain numerous spores. The evergreen stems are particularly noticeable in winter and can provide significant interest to the landscape. Stems have a high silica content and were used by early Americans for polishing pots and pans, hence the common name of scouring rush. Equisetum is not a rush however. Nor is it a fern. Equisetum is the single surviving genus of a class of primitive vascular plants that dates back to the mid-Devonian period (350 + million years ago). Today, the equisetums are categorized as fern allies in large part because they, like the ferns, are non-flowering, seedless plants which reproduce by spores.