Kingdom Protoctista Hogg, 1860
   Phylum Bacillariophyta Engl. & Gilg (1919) - diatoms see [unranked] Diatomea Kütz. (1844)
     Class Bacillariophyceae Haeckel (1878) - pennates
       Subclass Bacillariophycidae D.G.Mann (1990) - raphid diatoms
         Order Cymbellales D.G.Mann (1990)
           Family Cymbellaceae Grev. (1833)
             1 Genus Cymbella C.Agardh (1830)
             2 Genus Brebissonia Grunow (1860)
             3 Genus Encyonema Kütz. (1833)
             4 Genus Placoneis Mereschk. (1903)