Division Bacillariophyta Engl. & Gilg (1919) see Phylum Bacillariophyta Engl. & Gilg (1919)
   Class Coscinodiscophyceae Round & R.M. Crawford (1990) - radial centrics
     Subclass Coscinodiscophycidae Round & R.M. Crawford (1990)
       Order Melosirales R.M. Crawford (1990)
         Family Hyalodiscaceae R.M. Crawford (1990)
           1 Genus Hyalodiscusᵀ Ehrenb. (1845)
           2 Genus Podosira Ehrenb. (1840)