Dr Abe V Rotor
Equisetum is a "living fossil" as it is the only living genus in Equisetaceae, a family of vascular plants that reproduce by spores rather than seeds, and the only living member of the entire class Equisetopsida. It is also called horsetail, snake grass, puzzle grass, scouring-rush, candock, and other local names.
All horsetails today are distinctly and unmistakably the same morphologically and genetically. (A superficially similar but entirely unrelated flowering plant genus, mare's tail (Hippuris), is occasionally misidentified as "horsetail", and adding to confusion, the name mare's tail is sometimes applied to Equisetum.)
"The young plants are eaten cooked or raw. The fertile stems bearing strobili (spore casing) of some species are cooked and eaten like asparagus (a dish called tsukushi) in Japan. The people of ancient Rome would eat meadow horsetail in a similar manner, and they also used it to make tea as well as a thickening powder. Native Americans in the Pacific Northwest eat the young shoots of this plant raw. The plants are used as a dye and give a soft green colour. An extract is often used to provide silica for supplementation. Horsetail was often used by Indians to polish wooden tools. Equisetum species are often used to analyze gold concentrations in an area due to their ability to take up the metal when it is in a solution." (Wikipedia, citations and more data needed)