Division Bacillariophyta Engl. & Gilg (1919) see Phylum Bacillariophyta Engl. & Gilg (1919) Class Coscinodiscophyceae Round & R.M. Crawford (1990) - radial centrics Subclass Biddulphiophycidae Round & R.M. Crawford (1990) see Class Mediophyceae Medlin & Kaczmarska (2004) Order Hemiaulales Round & R.M. Crawford (1990) Family Hemiaulaceae Heib. (1863) Genus Baxteriopsis G. Karst. (1928)