Phylum [Tracheophyta] Sinnott ex Caval.-Sm. (1998) - vascular plants Subphylum Polypodiophytina Reveal (1996) [monotypic] Class Polypodiopsida Cronquist, Takht. & Zimmerm. (1966) - ferns Subclass Equisetidae Warm. (1883) [monotypic] Order Equisetales DC. ex Bercht. & J.Presl (1829) [monotypic] 4 Family Equisetaceae Michx. ex DC. (1804) [monotypic] - horsetails