Equisetum arvense, L.

Tutin, T. G., Heywood, V. H., Burges, N. A., Moore, D. M., Valentine, D. H., Walters, S. M. & Webb, D. A., 1964, Flora Europaea - Volume 1. Lycopodiaceae to Platanaceae, Cambridge University Press : 8

9. E. arvense L. , Sp. Pl. 1061 (1753).

Rhizome pubescent. Sterile stems 10-80 cm x (1—)3—5 mm, usually regularly and abundantly branched; branches ascending or suberect, simple; ridges nearly smooth; grooves (4—)6— 19; sheaths green; teeth as many as grooves; central hollow less than diameter of main stem. Fertile stems appearing before the sterile, usually shorter, simple, pale brown, dying after the spores are shed; sheaths 4-6, pale brown, with darker teeth. Cone (4-) 10-40 mm. 2n —c. 216. Throughout Europe. All except Az.

A serious weed in some areas. In small arctic plants, the fertile stems become green, at least below, and branch irregularly after the spores are shed.