Kingdom Protoctista Hogg, 1860
   Phylum Bacillariophyta Engl. & Gilg (1919) - diatoms see [unranked] Diatomea Kütz. (1844)
     Class Coscinodiscophyceae Round & R.M. Crawford (1990) - radial centrics
       Subclass Rhizosoleniophycidae Round & R.M. Crawford (1990)
         Order Rhizosoleniales P.C.Silva (1962)
           Family Rhizosoleniaceae De Toni (1890)
             Genus Guinardia H. Perag. (1892)