Nitzschia Guide
Credit: Marina Potapova, Sarah Hamsher, Sarah Spaulding
  1. Raphe eccentric, within a keel
  2. Keel supported by internal fibulae
  3. Raphe of each valve on opposite sides of the frustule

The nitzschioid raphe is positioned eccentrically within a keel which is supported by fibulae. Valves lack a sternum. Within the genus, species have a large range in size, from very small to very large.

Nitzschia is a very common genus with a large number of species that are often difficult to identify. Some Nitzschia species reach great abundance in waters high in organic pollution.