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 †Lyginopteridophyta Doweld (2001) [monotypic] see Division Pteridospermatophyta Meyen
             Class †Lyginopteridopsida Novák (1961)
               Order †Hexapterospermales Doweld (2001)
                 Family †Hexapterospermaceae Doweld (2001), nom. cons. prop. [monotypic]
                   1 Genus †Hexapterospermum Brongn. (1874)