Equisetum L.
Underground stems creeping, freely branching; aerial stems upright, often bearing whorls of branches, usually with a central hollow surrounded by 2 rings of alternating smaller cavities. Lvs in sheathing whorls at the nodes, small and brownish, toothed at the apices. Several sporangia borne on adaxial surface of heads of sporangiophores. Strobili usually terminal on main aerial stems.
15 spp., cosmopolitan except for Australia and N.Z.; plants of damp or wet habitats. Naturalised sp. 1.
