Like other diatoms, Gyrosigma has a siliceouscell wall called a frustule. The frustule is composed of two sections called valves, with one valve fitting inside the other valve similar to the two halves of a Petri dish.[2]Gyrosigma has valves with a central slit called a raphe, a structure that allows movement of these diatoms.[3]
The valves of Gyrosigma are sigmoid in outline, as well as the raphe. Striations could be parallel or perpendicular to the raphe. This contrasts to a similar genus Pleurosigma, which has striations that lie diagonally to the raphe.[3]
Species
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^Kociolek, J. Patrick; Theriot, Edward C.; Williams, David M.; Julius, Matthew; Stoermer, Eugene F.; Kingston, John C. (2014). "Chapter 15. Centric and Araphid Diatoms". In Wehr, John D.; Sheath, Robert G.; Kociolek, J. Patrick (eds.). Freshwater Algae of North America: Ecology and Classification (2 ed.). Elsevier Inc. ISBN978-0-12-385876-4.
^ abKociolek, J. Patrick; Spaulding, S. A.; Lowe, R. L. (2014). "Chapter 16. Bacillariophyceae: The Raphid Diatoms". In Wehr, John D.; Sheath, Robert G.; Kociolek, J. Patrick (eds.). Freshwater Algae of North America: Ecology and Classification (2 ed.). Elsevier Inc. ISBN978-0-12-385876-4.