Stems annual, monomorphic, hollow, branched or not, with 9 to 25 ridges, up to 1 m long, 2–8 mm wide. Sheaths green with black teeth. Branches with first internode shorter than subtending stem sheath. Strobili blunt, 5–30 mm long, maturing in summer.Unbranched plants resemble Equisetum laevigatum but the sheath teeth are not broken off (
Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).
Shallow water of ponds, lakes, sloughs, marshes, fens; plains, valleys to montane. (
Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).