Equisetum fluviatile

Kırkboğum

Stems up to 150 cm, erect, green, simple, or with whorls of branches in the middle and upper parts; grooves shallow, 10-30. Sheaths green; teeth as many as the grooves, black, not ribbed, subulate. Central hollow  ½ the stem diameter. Branches ascending, 5-angled, the lowest internode equalling or shorter than the stem sheath. Cone 1-2 cm. River banks, etc., up to 1500 m.

Temperate Eurasia, N. America.