- Rotational symmetry of cell face outline 180 degrees, one end is a reflection of the other
- Raphe absent
In this section
Pennate diatom, valves boat-shaped in valve view, cruciform (cross-like) or with an undulate outline in some species; rectangular in girdle view. Valves identical, neither possessing a raphe (genus is araphid). Striae do not meet in centre of the valve, where there is a thickened central sternum. Chloroplasts golden brown.