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.

Source: Webster's Revised Unabridged Dictionary (1913)