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 Bacillariophyceae Haeckel (1878) - pennates
                                           Subclass Fragilariophycidae Round (1990) - core araphid diatoms
                                             Order Fragilarialesᵀ P.C.Silva (1962) [monotypic]
                                               Family Fragilariaceaeᵀ Grev. (1833)
                                                 Genus Fragilariforma D.M. Williams & F.E. Round (1988)
                                                   Fragilariforma constricta (Ehrenberg, 1843) D.M. Williams & Round (1988)
                                                     Fragilariforma constricta f. stricta (A.Cleve, 1895) B. Hartley et al. (1996)