Cosmarium caelatum. Notice a more or less quadrate cell shape with four marked crenations at the apices. Each lateral semicell side with an upper and a (much larger) lower crenation.

Cell dimensions (L x B): 47 x 41 µm

Cosmarium caelatum, as found in the Netherlands (2004)




Desmid of the month
June 2019

Cosmarium caelatum

Cosmarium caelatum is a typical species of mountainous regions. It is readily to be recognized by its more or less quadrate cell shape, deeply crenate margins and supraisthmial inflation decorated with longitudinal rows of granules. In particular the series of four papillate, marked crenations at the truncate apex is most characteristic. In the Netherlands, Cosmarium caelatum is of very rare occurrence in the eastern part of the country.

Empty cell of Cosmarium caelatum showing pattern of cell wall granulation.
Notice marked, conical papillae at the crenate margins and curved, longitudinal series of granules on the supraisthmial inflation.

Image © Jan Šťastný

SEM-image of Cosmarium caelatum