Class Conjugatophyceae Engl. (1892) see Class Zygnematophyceae Round ex Guiry (2013) Order Zygnematales - filamentous conjugates and saccoderm desmids Family Zygnemataceae (Meneghini) Kützing (1843) Genus Mougeotia C.Agardh (1824), nom. cons. Mougeotia calcarea (Cleve) Wittrock