Freshwater Algae of North America
   Class Zygnematophyceae C.Hoek, D.G.Mann & H.M. Jahns (1995), nom. inval. - conjugating green algae see Class Zygnematophyceae Round ex Guiry (2013)
     Order Zygnematales [paraphyletic] - filamentous conjugates and saccoderm desmids
       .1 Family Mesotaeniaceae [polyphyletic]
       .2 Family Zygnemataceae (Meneghini) Kützing (1843) [polyphyletic]
       01 Genus Ancylonema Berggr. (1871) [monotypic]
       02 Genus Cylindrocystis Meneghini ex de Bary (1858)
       03 Genus Geniculus Prescott (1967) [monotypic]
       04 Genus Mesotaenium Nägeli (1849)
       05 Genus Mougeotia C.Agardh (1824), nom. cons.
       06 Genus Mougeotiopsis Palla (1894) [monotypic]
       07 Genus Netrium (Nägeli) Itzigs. & Rothe (1856)
       08 Genus Nucleotaenium A.A. Gontcharov & M. Melkonian (2010)
       09 Genus Planotaenium (Ohtani) Petlovany & Palamar-Mordvintseva (2009)
       10 Genus Pleurodiscus Lagerh. (1895)
       11 Genus Spirogyra Link (1820), nom. cons.
       12 Genus Spirotaenia Bréb. ex Ralfs (1848)
       13 Genus Temnogametum West & G.S.West (1897)
       14 Genus Tortitaenia (Brook) Brook
       15 Genus Transeauina Guiry (2013)
       16 Genus Zygnema C.Agardh (1817), nom. cons.
       17 Genus Zygnemopsis (Skuja) Transeau (1934)
       18 Genus Zygogonium Kütz. (1843), nom. cons.