Domain Eucaryota
   Subdomain Chlorota Doweld (2001)
     Kingdom Chlorobiota C.Jeffrey ex Doweld (2001) - plants see Subkingdom Viridiplantae Caval.-Sm. (1981)
       Subkingdom Pteridobiotina Britton & A. Br. (1896)
         Superphylum Cycadophytanae Doweld (2001)
           Phylum Cycadophyta Bessey (1907) see Subclass Cycadidae Pax (1894)
             1 Class †Pachytestopsida Doweld (2001)
             2 Class †Phasmatocycadopsida Doweld (2001)
             3 Class Cycadopsida Brongn. (1843)