Euastrum lacustre. Notice cell shape resembling that of Euastrum insulare.

Cell dimensions (L x B): 30 x 20 µm

 

* This taxon was originally described as Euastrum insulare var. lacustre, see:
Coesel, P.F.M., 1984. Taxonomic implications of SEM revealed cell wall sculpturing in some small-sized desmid species. Acta Botanica Neerlandica 33: 385-398.

 

 

Desmid of the month
August 2016

Euastrum lacustre

Euastrum lacustre* resembles Eu. insulare albeit that the sides of the basal part of the semicell usually are deeper incurved, thus giving rise to an extra lateral lobe. The most essential difference, however, is to be found in the sculpture of the cell wall. Whereas the cell wall of Eu. insulare shows fine pores often in combination with one or more scattered large pits, the cell wall in Eu. lacustre is distinctly scrobiculate (usually masking the proper pores). In the Netherlands, Eu. lacustre is of occasional occurrence in mesotrophic, sandy habitats, particularly in coastal regions.


Image © Alfred van Geest

Same cell of Eu. lacustre in lateral view showing semicells with a weak median protrusion.


Image © Alfred van Geest

Cell of Eu. lacustre in frontal view showing cell wall scrobicles in empty part of the semicell near the apex.

 

Image Hanny Kooijman née Van Blokland © IBED

SEM picture of Eu. lacustre. Notice coarse scrobiculation of the cell wall.

Image Hanny Kooijman née Van Blokland © IBED

SEM picture of the apex of Eu. lacustre in larger magnification showing cell wall pores among the scrobicles.