Equisetum fluviatile
Sp. Pl. 2: 1062. 1753.
Aerial stems monomorphic, green, unbranched or branched, 35–115 cm; hollow center large, to 9/10 stem diam.; vallecular canals absent. Sheaths squarish in face view, ca. 4–10 × 4–10 mm; teeth black, occasionally with narrow white border, 12–24, narrow, 2–3 mm. Branches when present only from midstem nodes, spreading, hollow, ridges 4–6, valleys rounded; 1st internode of each branch shorter than subtending stem sheath; sheath teeth narrow. 2n =216.
Phenology: Cones maturing in summer.
Habitat: Standing in water, in ponds, ditches, marshes, swales
Elevation: 0–1500 m
Distribution
St. Pierre and Miquelon, Alta., B.C., Man., N.B., Nfld. and Labr. (Nfld.), N.W.T., N.S., Ont., P.E.I., Que., Sask., Yukon, Alaska including the Aleutian Islands, Conn., Del., D.C., Idaho, Ill., Ind., Iowa, Maine, Md., Mass., Mich., Minn., Mont., Nebr., N.H., N.J., N.Y., N.Dak., Ohio, Oreg., Pa., R.I., S.Dak., Vt., Va., Wash., W.Va., Wis., Wyo., Eurasia s to n Italy, China, Korea, Japan
Discussion
Selected References
None.