Division Bacillariophyta Engl. & Gilg (1919) see Phylum Bacillariophyta Engl. & Gilg (1919) 1 Class Coscinodiscophyceae Round & R.M. Crawford (1990) - radial centrics 2 Class Fragilariophyceae Round (1990) - araphid, pennate diatoms see Class Bacillariophyceae Haeckel (1878) 3 Class Bacillariophyceae Haeckel (1878) - pennates