Image © Marien van Westen

Staurastrum crassangulatum. Notice the pentagonal shape of the semicells and the about rectangular lateral angles where cell wall is slightly thickened.
Cell dimensions (L x B): 46 x 34 µm

 

 

Desmid of the month
February 2020

Staurastrum crassangulatum

St. crassangulatum* is a smooth-walled, triradiate Staurastrum species. Main diagnostic feature is in the pentagonal shape of the semicells. Lateral angles are about rectangular and not seldom marked by a somewhat thickened cell wall. In the Netherlands, Staurastrum crassangulatum is of occasional occurence is slightly acidic, mesotrophic habitats, particularly in quaking fen hollows.


* Formerly known as
  St. orbiculare var. angulatum Kaiser and as St. kaiseri Růžička

Cosmarium margaritiferum
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Images © Alfred van Geest

Another cell of St. crassangulatum in frontal view showing its 3-radiate configuration.

 


Image © Alfred van Geest

Semicel van St. crassangulatum in apical view showing a central pyrenoid and in each radius a pair of chloroplast lobes.


Foto © Jan Šťastný

SEM image of St. crassangulatum. Note the scrobiculate cell wall.