Gomphonema acuminatum

Valves are clavate, tumid at the center with two constrictions along the margin; near the headpole the valve broadens and then becomes apiculate at the headpole, the footpole is rounded. The axial area is narrow, straight, until broadening to form an irregular central area. The central area bears a single stigma. The raphe is lateral and undulate. The external proximal raphe ends are dilated. The external distal raphe ends are deflected onto the mantle in the direction opposite the stigma. Striae are radiate, strongly so at the footpole. A bilobed apical pore field is present at the footpole. Septa and pseudosepta are present at the poles.