Natura - nature
  
 actualia - actual entities
    
 Mundus Plinius - physical world
      
 naturalia - natural bodies
        
 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
                            
 Clade Sar Adl et al. 2012 [Simpson & Dunthorn 2020]
                              
 Infrakingdom Halvaria Cavalier-Smith, 2010
                                
 Superphylum Heterokonta Caval.-Sm. (1986)
                                  
 Phylum Oomycota Arx (1967)
                                    
 Class "Hyphochytrea" Caval.-Sm. (1986), nom. inval.
                                      
 Order Pirsoniales Caval.-Sm. (1998) [monotypic]
                                        
 Family Pirsoniaceaeᵀ Caval.-Sm. (1998) [monotypic]
                                          
 1 Genus Pirsoniaᵀ Schnepf et al. (1990)