Kingdom Protoctista Hogg, 1860
Count: [p] 36p;91c;87o;183f;507g;35s;2v
   Phylum Bacillariophyta Engl. & Gilg (1919) - diatoms see [unranked] Diatomea Kütz. (1844)
  Count: [f] 4c;41o;83f;204g
     Class Coscinodiscophyceae Round & R.M. Crawford (1990) - radial centrics
    Count: 20o;33f;85g
       Subclass Biddulphiophycidae Round & R.M. Crawford (1990) see Class Mediophyceae Medlin & Kaczmarska (2004)
      Count: [f] 4o;4f;23g
         1 Order Eupodiscales see Order Triceratiales Round & R.M. Crawford (1990)
        Count: [f] 1f;7g
         2 Order Biddulphiales Willi Krieg. (1954)
        Count: [f] 1f;5g
         3 Order Hemiaulales Round & R.M. Crawford (1990)
        Count: [f] 1f;8g
         4 Order Anaulales Round & R.M. Crawford (1990)
        Count: [f] 1f;3g