general characters of equisetum
Answers
The leaves of horsetails are arranged in whorls fused into nodal sheaths. The stems are usually green and photosynthetic, and are distinctive in being hollow, jointed and ridged (with sometimes 3 but usually 6–40 ridges).
Answer:
Equisetum is the only living genus in Equisetaceae, a family of vascular plants that reproduce by spores rather than seeds.[2]
Equisetum
Temporal range: Callovian[1]-Holocene
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Equisetopsida.jpg
"Candocks" of the great horsetail (Equisetum telmateia subsp. telmateia), showing whorls of branches and the tiny dark-tipped leaves.
Scientific classificatione
Kingdom:Plantae
Class:Polypodiopsida
Order:Equisetales
Family:Equisetaceae
Genus:EquisetumL.
Equisetum is a "living fossil", the only living genus of the entire class Equisetopsida, which for over 100 million years was much more diverse and dominated the understory of late Paleozoic forests. Some Equisetopsida were large trees reaching to 30 meters tall.[3] The genus Calamites of the family Calamitaceae, for example, is abundant in coal deposits from the Carboniferous period. The pattern of spacing of nodes in horsetails, wherein those toward the apex of the shoot are increasingly close together, inspired John Napier to invent logarithms.[4]
A superficially similar but entirely unrelated flowering plant genus, mare's tail (Hippuris), is occasionally referred to as "horsetail", and adding to confusion, the name mare's tail is sometimes applied to Equisetum.[5]
Despite centuries of use in traditional medicine, there is no evidence that Equisetum has any medicinal properties.