Synedra Ehrenberg


Frustules araphid, symmetrical to the apical and transapical axes (except several species, e.g. S. cyclopum Brutschy, are asymmetrical to the apical axis). Cells single, in spray-like clusters or in small chains (the result of rapid vegetative cell division), but never occur in long filamentous/ribbon-like chains. Lack of a filamentous growth habit distinguishes Synedra from Fragilaria.

We have followed the classical circumscription of Synedra, although the genus has been split into several others by Williams and Round (198x) and lumped into Fragilaria by Krammer and Lange-Bertalot (1991). The question of araphid diatom interrelationships (and thus the assignment of species to genera) is still a vexing one, and until additional observations/arguments are made, we prefer, for the sake of stability, to continue to follow the classical interpretations.

Light Microscope Image(s)

Each image is accompanied by the genus and species, California Academy of Sciences slide number (ie. CAS 612010), location of the specimen on the slide, and dimension in microns.