[ noun ] horsetails; coextensive with the family Equisetaceae <noun.plant>
Equisetum \Eq`ui*se"tum\, n.; pl. {Equiseta}. [L., the horsetail, fr. equus horse + seta a thick,, stiff hair, bristle.] (Bot.) A genus of vascular, cryptogamic, herbaceous plants; -- also called {horsetails}.
Note: The {Equiseta} have hollow jointed stems and no true leaves. The cuticle often contains siliceous granules, so that one species ({E. hyemale}) is used for scouring and polishing, under the name of {Dutch rush} or {scouring rush}.