Green algae - Conjugate algae - Cosmarium
The genus Cosmarium is one of the largest genera of desmids. Over 2000 species have been described.
They are most abundant in water that is poor in salts of calcium, usually acid water with pH like 7.0-5,0 The cells are deeply incised with clear distinction into two halves. Under the cell division the two semi-cells separates, and each semi-cell then buds forth a new semicell. The cell wall is ornamented in different patterns, according to the species.
The size is about 60 my.