Kingdom Chlorobiota C.Jeffrey ex Doweld (2001) - plants see Subkingdom Viridiplantae Caval.-Sm. (1981)
   Subkingdom Pteridobiotina Britton & A. Br. (1896)
     Superdivision Cycadophytanae Doweld (2001) see Superphylum Cycadophytanae Doweld (2001)
       Division Cycadophyta Bessey (1907)
         Class Cycadopsida Brongn. (1843)
           Subclass Zamiidae Doweld (2001)
             b Order †Nilsoniales (1935), orth. inval. [monotypic] see Order Nilssoniales W.Zimm. (1930)
             c Order Zamiales Burnett (1835) [monotypic]