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 †Pteridospermatophyta Meyen
         Class †Lyginopteridopsida Novák (1961)
           Order †Hexapterospermales Doweld (2001)
             Family †Hexapterospermaceae Doweld (2001), nom. cons. prop.
               1 Genus †Hexapterospermum Brongn. (1874)
               2 Genus †Potoniea Zeiller (1899)