Division [Bacillariophyta] Engl. & Gilg (1919) see Phylum Bacillariophyta Engl. & Gilg (1919)
   [Subdivision] Coscinodiscophytina Medlin & Kaczmarska (2004) [monotypic] see Subphylum Coscinodiscophytina Medlin & Kaczmarska (2004)
     Class Coscinodiscophyceae Round & R.M. Crawford (1990) [paraphyletic] - radial centrics
       1 Order Aulacosirales (R.M. Crawford, 1990) see Order Aulacoseirales R.M. Crawford (1990)
       2 Order Rhizosoleniales P.C.Silva (1962)
       3 Order Leptocylindrales Round & R.M. Crawford (1990)
       4 Order Corethrales Round & R.M. Crawford (1990)