Class Conjugatophyceae Engl. (1892) see Class Zygnematophyceae Round ex Guiry (2013)
   Order Zygnematales - filamentous conjugates and saccoderm desmids
     Family Zygnemataceae (Meneghini) Kützing (1843)
       Genus Zygnema C.Agardh (1817), nom. cons.
         1 Zygnema cruciatum (Vaucher) C.Agardh
         2 Zygnema stellinum (O.F.Müll.) C.Agardh
         3 Zygnema pectinatum (Vaucher) C.Agardh
         4 Zygnema purpureum Wolle see Pleurodiscus purpureus (Wolle) Lagerh.