Equisetum(redirected from Horse-tail)
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Equisetumany pteridophyte plant of the genus Equisetum, comprising the horsetails. The plant is herbaceous, has rhizomes and a vertical stem with whorls of scale leaves, and is often found growing in water and damp conditions. It is the last living representative of the order Equisetales, members of which, during the time of the dinosaurs, grew as high as trees and were probably a major food source.
genus of the fern ally family Equisetaceae. These plants have a high content of thiaminase, and horses which eat a lot of them, usually in their hay, develop thiamin deficiency. This is characterized by incoordination, falling, bradycardia and severe cardiac irregularity. Response to treatment with thiamin is rapid and complete.
Includes E. arvense, E. hyemale, E. laevigatum, E. limosum, E. palustre, E. ramosissimum. Called also horsetails, foxtails, marestails.