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 Cystosiphon Roze & Cornu (1869)
               Genus Diasporangium Höhnk (1936)
               Genus Halophytophthora H.H. Ho & S.C. Jong (1990)
               Genus Lagenidium Schenk (1857)
               Genus Lucidium Lohde (1874), nom. dub.
               Genus Myzocytium Schenk (1858)
               Genus Phytophthora de Bary (1876)
               Genus Pythium Pringsh. (1858), nom. cons.
               Genus Trachysphaera Tabor & Bunting (1923)
               Genus Peronophythora C.C. Chen ex W.H. Ko, H.S. Chang, H.J. Su, C.C. Chen & L.S. Leu (1978)