Class Conjugatophyceae Engl. (1892) see Class Zygnematophyceae Round ex Guiry (2013) Genus Spirotaenia Bréb. ex Ralfs (1848), incertae sedis Spirotaenia closteridia (Bréb. ex Kützing) Rabenh. (1868) Spirotaenia obscura Ralfs 2 Spirotaenia condensata Bréb. ex Ralfs