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]
           Domain Bacteria Woese et al. 1990 [paraphyletic?]
             Superphylum Terrabacteria Battistuzzi et al. 2004
               Phylum Cyanobacteria (ex Stanier 1974) Cavalier-Smith 2002 - cyanobacteria
                 Class "Cyanobacteria" Cavalier-Smith, 2002
                   Subclass Nostocophycideae
                     Order Nostocalesᵀ Borzì (1914)
                       Family Nostocaceaeᵀ Eichler (1886)
                         Subfamily Nostocoideaeᵀ
                           Genus Trichormus (J. Ralfs ex E. Bornet & C. Flahault) J. Komárek & K. Anagnostidis (1989)
                             Trichormus azollae (E.A. Strasburger ex Wittrock et al.) J. Komárek and K. Anagnostidis 1989
                             Trichormus variabilis (F.T. Kützing ex E. Bornet and C. Flahault 1888) J. Komárek and K. Anagnostidis 1989