Fragilariophyceae

Asterionella is a genus of pennate freshwater diatoms. They are frequently found in star-shaped colonies of individuals.

Fragilariophyceae is a group of pennate diatoms lacking a raphe.

Fragilaria is a genus of freshwater and saltwater diatoms. It is usually a colonial diatom, forming filaments of cells mechanically joined by protrusions on the face and in the center of their valves. The individual diatoms appear swollen in their centers where they are joined to the colonial ribbon. The genus grows as both plankton and benthic species, free living in colonies or as epiphytes. Some species are bloom forming diatoms in eutrophic lakes. The type species is Fragilaria pectinalis Lyngbye from designating a lectotype from Conferva pectinalis O.F.Müller. The taxonomy of the genus is

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Meridion is a genus of diatoms belonging to the family Fragilariaceae.