Division Bacillariophyta Engl. & Gilg (1919) see Phylum Bacillariophyta Engl. & Gilg (1919) Class Fragilariophyceae Round (1990) - araphid, pennate diatoms see Class Bacillariophyceae Haeckel (1878) Subclass Fragilariophycidae Round (1990) - core araphid diatoms Order Fragilariales P.C.Silva (1962) 1 Family Fragilariaceae Grev. (1833)