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 Desmidiales - placoderm desmids
       Family Desmidiaceae Kützing ex Ralfs (1845)
         01 Genus Actinotaenium (Nägeli) Schellenb. (1897)
         02 Genus Bambusina Kütz. ex Kütz. (1849), nom. cons.
         03 Genus Cosmarium Corda ex Ralfs (1848)
         04 Genus Cosmocladium Bréb. (1856)
         05 Genus Desmidium C.Agardh ex Ralfs (1848)
         06 Genus Didymoprium Kütz. ex Ralfs (1848)
         07 Genus Docidium Bréb. ex Ralfs (1848)
         08 Genus Euastrum Ehrenb. ex Ralfs (1848)
         09 Genus Groenbladia Teiling (1952)
         10 Genus Haplotaenium Bando
         11 Genus Heimansia Coesel
         12 Genus Hyalotheca Ehrenb. ex Ralfs (1848)
         13 Genus Mateola Salisb.
         14 Genus Micrasterias C.Agardh ex Ralfs (1848)
         15 Genus Octacanthium (Hansgirg) Compère
         16 Genus Oocardium Nägeli (1849) [monotypic]
         17 Genus Phymatodocis Nordst. (1877)
         18 Genus Pleurotaenium Nägeli (1849)
         19 Genus Sphaerozosma Ralfs (1848)
         20 Genus Spinocosmarium Prescott & A.M.Scott (1942)
         21 Genus Spondylosium Bréb. ex Kütz. (1849)
         22 Genus Staurastrum Meyen ex Ralfs (1848)
         23 Genus Staurodesmus Teiling (1948)
         24 Genus Teilingia Bourr. (1964)
         25 Genus Tetmemorus Ralfs (1848)
         26 Genus Triploceras Bailey (1851)
         27 Genus Xanthidium Ehrenb. ex Ralfs (1848)