EQUISETUM
Equisetum, genus Equisetum
(noun) horsetails; coextensive with the family Equisetaceae
Source: WordNet® 3.1
Etymology
Noun
equisetum (plural equisetums or equiseta)
The horsetail (plant of genus Equisetum)
Source: Wiktionary
Eq`ui*se"tum, n.; pl. Equiseta. Etym: [L., the horsetail, fr. equus
horse + seta a thick,, stiff hair, bristle.] (Bot.)
Definition: 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 Unabridged Dictionary 1913 Edition