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 Chaetocerophycidae see Subclass Chaetocerotophycidae Round & R.M. Crawford (1990) 1 Order Chaetocerotales Round & R.M. Crawford (1990) 2 ?Order Leptocylindrales Round & R.M. Crawford (1990)