Cell of Euastrum didelta. Notice large dimensions, pyramidal outline of semicells and undivided, basal lobes.
Cell dimensions (L x B): ca 140 x 80 µm


Desmid of the month
January 2024

Euastrum didelta

Euastrum didelta should be compared with E. humerosum. Both species are rather large-sized, with pyramidal semicells that are markedly undulate in outline and provided with a deep, closed apical invagination. Main difference is in de shape of the basal lobes: entire in Eu. didelta, incurved (showing two lobules) in Eu. humerosum. Sometimes, however, intermediate cell forms are encountered rendering identification problematic. In the Netherlands, Euastrum didelta is of incidental occurrence in various oligo-mesotrophic pools.

Same cell of Eu. didelta but focussed on cell surface (showing a distinct supraisthmial tubercle).

Another cell of Eu. didelta in which the semicell outline is less pyramidal (a bit resembling that in Eu. humerosum).