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 Gnetophyta Bessey (1907) [monotypic]
         Class Gnetopsida Eichler ex Kirpot. (1884)
           Order Ephedrales Dumort. (1829) [monotypic]
             Family Ephedraceae Dumort. (1829), nom. cons. - Mormon-tea family
               Genus †Siphonospermum Rydin & E.M.Friis (2010)