Pennate diatoms. The cells are enclosed in siliceous valves. There are typically two valves - a top one and a lower one, and they are joined together with fine bands or girdle strips. With plastids containing chlorophylls a and c (they are stramenopiles after all). Genera and species distinguished largely by the shape of the organism and the pattern of pores and sculptings of the siliceous shell or frustule. This pennate diatom is seen in valve view, there is an H shaped zone without sculptings in the frustule. Large plastids. The raphe is the two-part line running axially along the centre of the valve. Differential interference contrast.
