Phylum Cyanobacteria Garcia-Pichel et al. (2020) see Phylum Cyanobacteriota Oren et al. 2022
   Class Cyanophyceae Hauck (1885) see Class Chroococcophyceae Hollerbach et al. 1953
     Order Nostocales Borzì (1914) see Order Nostocales corrig. Borzì 1914
       1 Family Capsosiraceae L. Geitler (1925), incertae sedis see Family Capsosiraceae Geitler 1925
       2 Family Geitleriaceae C. Kilgore & J.R.Johans. (2018), incertae sedis [monotypic] see Family Hapalosiphonaceae Elenkin 1917
       3 Family Rhizonemataceae Büdel & Kauff ex Lücking & Barrie (2014), incertae sedis [monotypic] see Family Rhizonemataceae Büdel and Kauff ex Lücking and Barrie 2014
       4.1 Family Rivulariaceae Frank (1886) see Family Rivulariaceae Frank 1886
       4.2.1 Family Scytonemataceae A.B.Frank (1886) see Family Scytonemataceae corrig. Frank 1886
       4.2.2 Family Hapalosiphonaceae Elenkin (1917), nom. cons. see Family Hapalosiphonaceae Elenkin 1917
       5.1.1 Family Heteroscytonemataceae McGregor & Sendall (2018) [monotypic] see Family Heteroscytonemataceae McGregor and Sendall 2018
       5.1.2 Family Stigonemataceae Borzì (1892), nom. cons. see Family Stigonemataceae corrig. (Agardh ex Bornet and Flahault 1886) Borzì 1892 nom. cons.
       5.2.1 Family Tolypotrichaceae Hauer, Bohunická, J.R.Johans., Mareš & Berrendero-Gomez (2014) see Family Tolypotrichaceae corrig. Hauer et al. 2014
       5.2.2.1 Family Leptobasaceae Elenkin (1917), nom. illeg. see Family Nostocaceae Eichler 1886
       5.2.2.2.1.1 Family Nostocaceae Eichler (1886) see Family Nostocaceae Eichler 1886
       5.2.2.2.1.2 Family Aphanizomenonaceae Elenkin (1938), orth. inval. see Family Aphanizomenaceae corrig. Elenkin 1938
       5.2.2.2.2 Family Nodulariaceae Elenkin (1916) see Family Nodulariaceae Elenkin 1916