Kingdom [Plantae] Haeckel (1866) - plants
   Division Pteridophyta Schimp. (1879) see Subphylum Pteridophytina (Eichler) Cavalier-Sm. (1998)
     Class Equisetopsida C.Agardh (1825) - horsetails see Subclass Equisetidae Warm. (1883)
       Order Equisetales DC. ex Bercht. & J.Presl (1829)
         1 Family †Archaeocalamitaceae Stur see Family Calamostachyaceae S.V.Meyen (1978), nom. cons. prop.
         2 Family †Calamostachyaceae S.V.Meyen (1978), nom. cons. prop.
         3 Family †Tchernoviaceae S.V.Meyen (1983)
         4 Family †Gondwanostachyaceae S.V.Meyen (1983), nom. cons. prop.
         5 Family Equisetaceae Michx. ex DC. (1804) - horsetails
         6 Family †Echinostachyaceae Grauvogel-Stamm (1978), nom. cons. prop.