Staurastrum tetracerum
Image © Alfred van Geest

Staurastrum tetracerum. Notice four, strongly divergent processes only one of which is in full focus indicating a twisted isthmus.

Cell dimensions (L x B): ca 30 x 30 µm


Image © Alfred van Geest

Another picture of St. tetracerum showing the torsion between the semicells even better.

 

 

Desmid of the month
November 2020

Staurastrum tetracerum

 St. tetracerum is a rather small-sized Staurastrum species marked by some four, divergent processes produced from the apical angles of a bowl-shaped to rectangular semicell body. Most characteristic is the torsion of the isthmus between the two semicells as a consequence of which the four processes are but seldom in focus at the same time. Both semicell body and processes are furnished with widely placed, tiny denticulations. In the Netherlands, Staurastrum tetracerum is fairly common in various meso-eutrophic water bodies.

Image Hanny Kooijman née Van Blokland © IBED 

SEM picture of St. tetracerum

 

Image Hanny Kooijman née Van Blokland © IBED 

 

SEM picture of St. tetracerum in more detail. Notice scattered denticulations.