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 Gnetophyta Bessey (1907) see Subclass Gnetidae Pax (1894)
             Class Welwitschiopsida Boivin (1956) [monotypic]
               1 Order Welwitschiales Skottsb. ex Reveal (1993) [monotypic]