Kingdom Protoctista Hogg, 1860 Phylum Bacillariophyta Engl. & Gilg (1919) - diatoms see [unranked] Diatomea Kütz. (1844) 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) 2 Family Tabellariaceae Kütz. (1844) 3 Family Licmophoraceae Kütz. (1844)