Cell of Micrasterias oscitans (sampled in the Czech Republic). Notice the broad, domed apical lobe and the undivided lateral lobes. The bidentate lateral lobes often have an additional dentation  at their upper margin.

Cell dimensions (L x B): ca 150 x 130 µm

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Desmid of the month
January 2008

Micrasterias oscitans

M. oscitans is a characteristically shaped Micrasterias species with an amphi-atlantic distribution (Europe and North America, in particular in the Atlantic climate region). Obviously it is nowhere common. In the Netherlands, M. oscitans is characteristic of acidic, ombrotrophic peat bog vegetation, with a slight input of minerals from the surroundings. The latest record (of living cells) dates from  1977. Possibly, its going down has to do with the industrial acidification of precipation in the second half of the 20th century.