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 Genus Cylindrocystis Meneghini ex de Bary (1858) Cylindrocystis brebissonii (Meneghini ex Ralfs) de Bary 1 Cylindrocystis brebissonii f. cryophila Kol