Equisetum is a genus of vascular plants that reproduce by spores rather than seeds. The genus includes 15 species commonly known as horsetails and scouring rushes . It is the only living genus in class Equisetopsida , formerly of the division Equisetophyta (Arthrophyta in older works), though recent molecular analyses place the genus within the ferns ( Pteridophyta ). [1] Other classes and orders of Equisetopsida are known from the fossil record, where they were important members of the world flora during the Carboniferous period.