Class Cyanoprokaryota Komárek & Golubić 1990 nom. nud. - cyanoprokaryotes
   Subclass Nostocophycidae Hoffmann, Komárek & Kaštovský (2005), nom. inval. [monotypic]
     Order Nostocales Borzì (1914) see Order Nostocales corrig. Borzì 1914
       01 Family Scytonemataceae A.B.Frank (1886) see Family Scytonemataceae corrig. Frank 1886
       02 Family "Symphyonemataceae" Hoffmann, Komárek & Kaštovský (2005), nom. inval. see Family Scytonemataceae A.B.Frank (1886)
       03 Family Borzinemataceae L. Geitler (1942) see Family Borzinemataceae Geitler 1942
       04 Family Rivulariaceae Frank (1886) see Family Rivulariaceae Frank 1886
       05 Family Microchaetaceae Lemmermann (1907) see Family Rivulariaceae Frank (1886)
       06 Family Nostocaceae Eichler (1886) see Family Nostocaceae Eichler 1886
       07 Family Chlorogloeopsidaceae Mitra & Pandey (1967) [monotypic] see Family Chlorogloeopsidaceae Mitra and Pandey 1967
       08 Family Hapalosiphonaceae Elenkin (1917), nom. cons. see Family Hapalosiphonaceae Elenkin 1917
       09 Family Loriellaceae Geitler (1925) see Family Hapalosiphonaceae Elenkin 1917
       10 Family Stigonemataceae Borzì (1892), nom. cons. see Family Stigonemataceae corrig. (Agardh ex Bornet and Flahault 1886) Borzì 1892 nom. cons.