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 Cycadophyta Bessey (1907) see Subclass Cycadidae Pax (1894) Class †Phasmatocycadopsida Doweld (2001) Order †Gigantopteridales X.X.Li & Z.Q. Yao (1983) Family †Spermopteridaceae Doweld (2001) Genus †Spermopteris Cridland & J.E.Morris (1960)