Division Bacillariophyta Engl. & Gilg (1919) see Phylum Bacillariophyta Engl. & Gilg (1919)
   Class Coscinodiscophyceae Round & R.M. Crawford (1990) - radial centrics
     Subclass Biddulphiophycidae Round & R.M. Crawford (1990) see Class Mediophyceae Medlin & Kaczmarska (2004)
       Order Anaulales Round & R.M. Crawford (1990)
         Family Anaulaceae Lemmerm. (1899)
           Genus Porpeia Bailey ex Ralfs (1861)