Kingdom Plantae Haeckel (1866) - plants
   Subkingdom Rhodoplantae G.W.Saunders & Hommers. (2004)
     Phylum Rhodophyta Wettst. (1901) - red algae
       Subphylum Rhodellophytina Caval.-Sm. (1998) [monotypic]
         Class Rhodellophyceae Caval.-Sm. (1998) [paraphyletic?]
           Order Porphyridiales Kylin ex Skuja (1939)
             .1 Genus Flintiella F.D. Ott (1970)
             .2 Genus Porphyridium Nägeli (1849), nom. cons.
             1 Family Porphyridiaceae Skuja