Asterionella

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

== Description == Asterionella average cell size is 60–85 micrometers long and 2–4 micrometers wide. It forms colonies that often consist of eight cells, but can vary up to 20 cells. The cells in the colony are attached by the apex by extracellular matter. By the way the cells are attached to each other, the colonies often look like stars or spiraling chains.