Class Conjugatophyceae Engl. (1892) see Class Zygnematophyceae Round ex Guiry (2013) Order Desmidiales - placoderm desmids Family Closteriaceae A. Pritch. (1872) 1 Genus Closterium Nitzsch ex Ralfs (1848) 2 Genus Spinoclosterium C.Bernard (1909)