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

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 epiphytic. 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 still uncertain.

Fragilariophyceae is a group of pennate diatoms lacking a raphe.

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

Fragilariophyceae is a group of pennate diatoms lacking a raphe.

Tabellaria is a genus of freshwater diatoms (Bacillariophyta). They are cuboid in shape, and the frustules are attached at the corners so that the colonies assume a zigzag shape.

Thalassionema is a genus of Chromista belonging to the family Thalassionemataceae.

Thalassionema nitzschioides is a type of phytoplankton belonging to the pennate diatom group.