Natura - nature
   actualia - actual entities
     Mundus Plinius - physical world
       naturalia - natural bodies
         [crown] Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
           Clade neomura Cavalier-Smith, 1987
             Domain Eukaryota Chatton, 1925 - eukaryotes
               Clade discaria Cavalier-Smith, 2021
                 Clade natates Cavalier-Smith, 2021
                   Clade photaria Cavalier-Smith, 2021
                     Clade eucorta Cavalier-Smith, 2021
                       Superkingdom Corticata Lankester, 1878 - corticates
                         Kingdom Chromista Caval.-Sm. (1981) - chromists
                           Subkingdom Harosa Cavalier-Smith, 2010
                             [crown] Clade Sar Adl et al. 2012 [Simpson & Dunthorn 2020]
                               Infrakingdom Halvaria Cavalier-Smith, 2010
                                 Superphylum Heterokonta Caval.-Sm. (1986)
                                   Phylum Ochrophyta Caval.-Sm. (1995)
                                     Subphylum Khakista Caval.-Sm. (2000)
                                       Diatomea Kütz. (1844)
                                         Class Coscinodiscophyceae Round & R.M. Crawford (1990) [paraphyletic] - radial centrics
                                           Subclass Coscinodiscophycidaeᵀ Round & R.M. Crawford (1990)
                                             Order Coscinodiscalesᵀ Round & R.M. Crawford (1990)
                                               Family Hemidiscaceae Hendey (1937)
                                                 Genus Actinocyclus Ehrenb. (1837)
                                                   Actinocyclus cholnokyi VanLand. (1967)
                                                   Actinocyclus curvatulus Janisch, in Schmidt (1878)
                                                   Actinocyclus ehrenbergi
                                                   Actinocyclus kuetzingii (A.Schmidt, 1878) Simonsen (1975)
                                                   Actinocyclus normanii (Gregory ex Grev., 1859) Hustedt (1957)
                                                   Actinocyclus octonarius Ehrenb.
                                                   Actinocyclus ralfsii (W.Sm.) Ralfs, in Pritchard
                                                   Actinocyclus roperi (Bréb.) Grunow, in Van Heurck (1881)