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)
           1 Family Cymbellaceae Grev. (1833)
           2 Family Gomphonemataceae Kütz. (1844)
           3 Family Anomoeoneidaceae D.G.Mann (1990)
           4 Family Rhoicospheniaceae Chen & Zhu (1983)