\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}.