Division [Bacillariophyta] Engl. & Gilg (1919) see Phylum Bacillariophyta Engl. & Gilg (1919)
   [Subdivision] Bacillariophytina Medlin & Kaczmarska (2004) see Subphylum Bacillariophytina Medlin & Kaczmarska (2004)
     Class Mediophyceae Medlin & Kaczmarska (2004) [paraphyletic] - bipolar centrics
       1 Order Thalassiosirales Glezer & I.V. Makarova (1986)