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)