Division Bacillariophyta Engl. & Gilg (1919) see Phylum Bacillariophyta Engl. & Gilg (1919)
   Class Bacillariophyceae Haeckel (1878) - pennates
     Subclass Bacillariophycidae D.G.Mann (1990) - raphid diatoms
       Order Surirellales D.G.Mann (1990)
         Family Surirellaceae Kütz. (1844)
           Genus Plagiodiscus Grunow & Eulenst. (1867)