Morphology of the marine benthic diatom Achnanthes pseudogroenlandica hendey (Bacillariophyceae)

A marine benthic diatom Achnanthes pseudogroenlandica Hendey was observed with light microscope and scanning electron microscope. The following morphological characteristics are revealed through this study; i) two plastids, each consisting of two girdle-appressed plates connected by a narrow bridge; ii) lanceolate to slightly clavate valve shape, which is heteropolar in the breadth of valve face and the length of raphe branch; iii) uniseriate striae consisting of round areolae occluded by rota supported by two pegs, and iv) the mature cingula consisted of at least three open bands, a broad valvocopula, the fimbriate second band with ligula, and the third band with ligula. This taxon forms colonies composed of two to four cells and attaches to substrata by the mucilage pad secreted from part of the raphe near both poles.