Chaetoceros is probably the largest genus of marine planktonic diatoms with approximately 400 species described, although many of these descriptions are no longer valid. It is often very difficult to distinguish between different Chaetoceros species. Several attempts have been made to restructure this large genus into subgenera and this work is still in progress. However, most of the effort to describe species has been focused in boreal areas, and the genus is cosmopolitan, so there are probably many tropical species still undescribed. Some species are known from the fossil record, from the Quaternary of Sweden. It is the type genus of its family.
Bacteriastrum is a genus of diatoms in family Chaetocerotaceae. There are more than 30 described species in genus Bacteriastrum, but many of these are not currently accepted, and new species are still added to the genus. The type species for the genus is Bacteriastrum furcatum Shadbolt.
Craticula is a genus of diatom that lies on or in the top layers of sediments in the freshwater to brackish water environments it inhabits. In addition to frustule morphology the genus differs from closely related species by its sexual reproduction and movement in response to light.
Cymbella inelegans is a diatom species in the genus Cymbella. It is a fresh water diatom species found in the United States.
Navicula baardsethii is a species of algae in the genus Navicula.
Navicula depressa is a freshwater species of algae of in the genus Navicula. Navicula depressa occurs in Fennoscandia.
Navicula my is a species of algae in the genus Navicula.
Thalassiothrix is a genus of Chromista belonging to the family Thalassionemataceae.
Achnanthes is a genus of diatoms belonging to the family Achnanthaceae.
Eucocconeis is a genus of diatoms belonging to the family Achnanthidiaceae.
Halamphora is a genus of diatoms belonging to the family Amphipleuraceae.
Cochlodinium is a genus of dinoflagellates belonging to the family Gymnodiniaceae.
Cosmioneis is a genus of diatoms belonging to the family Cosmioneidaceae.
Cymatopleura is a genus of diatoms belonging to the family Surirellaceae.
Detonula is a genus of diatoms belonging to the family Thalassiosiraceae.
Gomphocymbella is a genus of diatoms belonging to the family Cymbellaceae.
