Division Bacillariophyta Engl. & Gilg (1919) see Phylum Bacillariophyta Engl. & Gilg (1919) Class Coscinodiscophyceae Round & R.M. Crawford (1990) - radial centrics Subclass Coscinodiscophycidae Round & R.M. Crawford (1990) Order Orthoseirales R.M. Crawford (1990) Family Orthoseiraceae R.M. Crawford (1990) 1 Genus Orthoseira Thwaites (1848)