Symmetric Biraphid
Envekadea
- Raphe straight
- Distal raphe ends deflected to opposite sides
Species within the genus Envekadea are naviculoid, with a sigmoid raphe. The areolae are large and composed of rectangular to irregular polygons. Externally, the areolae are occluded by hymenes. The copulae are unoramented. A single chloropolast is present, which is H-shaped in valve view. Envekadea includes the former Navicula hedinii...