organisms see Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
   Domain Eukaryota Chatton, 1925 - eukaryotes
     Kingdom Chromista Caval.-Sm. (1981) - chromists
       Phylum Oomycota Arx (1967)
         Class Oomycetes G.Winter (1880) - oomycetes see Class Peronosporea
           Order Pythiales
             Family Pythiaceae
               Genus Pythium Pringsh. (1858), nom. cons.