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 spiralling chains. Reproduction The silica skeleton of a diatom cell (called the frustule) consists of an epitheca and an hypotheca. The hypotheca is slightly smaller than the epitheca. During asexual reproduction both thecae form the epitheca of the new daughter cell and each daughter produces a new hypotheca. Therefore one daughter cell is always smaller than the original cell. In order to regain their original size, it is usually assumed diatoms have to reproduce sexually, although this has not yet been obs ...
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Asterionella Formosa
''Asterionella formosa'' is a species of diatom belonging to the family Tabellariaceae. It has cosmopolitan distribution In biogeography, cosmopolitan distribution is the term for the range of a taxon that extends across all or most of the world in appropriate habitats. Such a taxon, usually a species, is said to exhibit cosmopolitanism or cosmopolitism. The ext .... References {{Taxonbar, from=Q49600081 Fragilariophyceae ...
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