[Class] Cyanobacteria "Stanier (1974)", nom. inval. - cyanoprokaryotes see Class Cyanophyceae Hauck (1885)
   Order Oscillatoriales Schaffner (1922) [paraphyletic] see Order Oscillatoriales Schaffner 1922
     Family Oscillatoriaceae Engl. (1898), nom. cons. see Family Oscillatoriaceae Engler 1898 nom. cons.
       Genus Phormidium Kütz. ex Gomont (1892) see Genus Phormidium Kützing ex Gomont 1892