Division [Bacillariophyta] Engl. & Gilg (1919) see Phylum Bacillariophyta Engl. & Gilg (1919)
   [Subdivision] Bacillariophytina Medlin & Kaczmarska (2004) see Subphylum Bacillariophytina Medlin & Kaczmarska (2004)
     Class Bacillariophyceae Haeckel (1878) - pennates
       1 Subclass Urneidophycidae Medlin (2016) - basal araphid diatoms
       2.1 Subclass Fragilariophycidae Round (1990) - core araphid diatoms
       2.2 Subclass Bacillariophycidae D.G.Mann (1990) - raphid diatoms