Fragilariopsis oceanica

Forms ribbon-shaped colonies that can be straight, curved or twisted about the apical axis showing some cells in broad girdle view and some in narrow girdle view. There is no interspace between adjacent cells. The cells are rectangular in girdle view. Each cell contains two chloroplasts located along the girdle. The valves are isopolar, subcircular to elliptical with outlines varying according to length of the valves. Valves have an eccentric raphe with a central nodule, the raphe running along the bend between valve and mantle and approximately same number of striae and fibulae.