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
       Family Hapalosiphonaceae Elenkin (1917), nom. cons. see Family Hapalosiphonaceae Elenkin 1917
         01 Form genus Albrightia Copel. (1936) see Genus Albrightia Copeland 1936
         02 Form genus Brachytrichiopsis Jao (1944) see Genus Brachytrichiopsis Jao 1944
         03 Form genus Chondrogloea W. Schmidle (1901) see Genus Chondrogloea Schmidle 1901
         04 Genus Fischerella (Bornet & Flahault) Gomont (1895) see Genus Fischerella (Bornet and Flahault 1886) Gomont 1895
         05 Genus Hapalosiphon C. Nägeli ex Bornet & Flahault (1886) see Genus Hapalosiphon Nägeli ex Bornet and Flahault 1886
         06 Form genus Leptopogon Borzì (1907) see Genus Leptopogon Borzì 1907
         07 Form genus Loefgrenia Gomont (1896) see Genus Loefgrenia Gomont 1896
         08 Genus Mastigocladus F.J. Cohn ex O. Kirchner (1898) see Genus Mastigocladus Cohn ex Kirchner 1898
         09 Form genus Matteia A. Borzì (1907) see Genus Matteia Borzì 1907
         10 Form genus Mastigocoleopsis Geitler (1925) see Genus Mastigocoleopsis Geitler 1925
         11 Form genus Mastigocoleus G. Lagerheim ex Bornet & Flahault (1886) see Genus Mastigocoleus Lagerheim ex Bornet and Flahault 1886
         12 Genus Nostochopsis Wood ex Bornet & Flahault (1886) see Genus Nostochopsis Wood ex Bornet and Flahault 1886
         13 Form genus Parthasarathiella N. Suba Raju (1962) see Genus Parthasarathiella Suba Raju 1962
         14 Form genus Thalpophila Borzì (1907) see Genus Thalpophila Borzì 1907
         15 Form genus Westiella Borzì (1907) see Genus Westiella Borzì 1907
         16 Genus Westiellopsis Janet (1941) see Genus Westiellopsis Janet 1941
         17 "T-Stigonematales"