and see text
Equisetum (pronounced /ˌɛkwɨˈsiːtəm/) (horsetail, snake grass, puzzlegrass) is the only living genus in the Equisetaceae, a family of vascular plants that reproduce by spores rather than seeds. )
Equisetum is a "living fossil", as it is the only living genus of the entire class Equisetopsida, which for over one hundred million years was much more diverse and dominated the understory of late Paleozoic forests. Some Equisetopsida were large trees reaching to 30 meters tall; the genus Calamites of family Calamitaceae for example is abundant in coal deposits from the Carboniferous period.
A superficially similar but entirely unrelated flowering plant genus, mare's tail (Hippuris), is occasionally misidentified and misnamed as "horsetail".
The name "horsetail", often used for the entire group, arose because the branched species somewhat resemble a horse's tail. Similarly, the scientific name Equisetum derives from the Latin equus ("horse") + seta ("bristle").
Other names include candock for branching individuals, and scouring-rush for unbranched or sparsely branched individuals. The latter name refers to the plants' rush-like appearance, and to the fact that the stems are coated with abrasive silicates, making them useful for scouring (cleaning) metal items such as cooking pots or drinking mugs, particularly those made of tin. In German, the corresponding name is Zinnkraut ("tin-herb"). Rough horsetail E. hyemale is still boiled and then dried in Japan, to be used for the final polishing process on woodcraft to produce a smoother finish than any sandpaper.
Full article ▸