Kingdom Chlorobiota C.Jeffrey ex Doweld (2001) - plants see Subkingdom Viridiplantae Caval.-Sm. (1981)
   Subkingdom Pteridobiotina Britton & A. Br. (1896)
     Superdivision Pteridophytanae Doweld (2001) [monotypic] see Superphylum Pteridophytanae Doweld (2001)
       Division Monilophyta Cantino & Donoghue
         Class Equisetopsida C.Agardh (1825) - horsetails see Subclass Equisetidae Warm. (1883)
           Order †Cladoxylales W.Zimm. (1930)
             Family †Iridopteridaceae C.A.Arnold (1940)
               1 Genus †Arachnoxylon Read (1939)
               2 Genus †Iridopteris C.A.Arnold (1940)