marsh horsetail

Equisetum palustre has stems growing between 10-60 cm tall. The upright stems are usually scarcely branched with loose green leaf sheaths that have 5-10 narrow, dark teeth. The teeth are light at the edges. The lowest internode of the upright branches are much shorter than the leaf sheath of the stem. The rough, furrowed stem is 1–3 mm diameter, with usually 8–10 ribs, in rare cases, 4–12; it bears a variable number of whorled branches. The spores are spread by the wind (anemochory) and have four long ribbon-like structures attached to them. The spores sit on strobili which are rounded on the top. Marsh horsetails often form runners, with which they also can proliferate vegetatively.

Equisetum palustre is green from spring to autumn and grows spores from June to September. It grows primarily in nutrient-rich wet meadows. It is found in Europe and the circumpolar region up to mountainous heights. Its distribution is declining. In Finland, it has benefited from human action and grows often in road and track sides, ditches and especially peat based fields and pastures. A specific plant association in which E. palustre is found is the Juncus subnodulosus-Cirsium palustre fen-meadow.