Euastrum ansatum. Cell in frontal view. Notice pyramidal outline of the semicells with a deep, median incision at the apex and rudimentarily developed lateral lobes in between the apical lobe and the basal lobes. Chloroplast with a single, central pyrenoid.

Cell dimensions (L x B): 80 x 40 µm

Euastrum ansatum. Cell in lateral view. Notice inflation in about the middle of the semicells.

Image © Jan Šťastný

Another SEM picture of Eu. ansatum showing cell wall pores among the wrinkles.



Desmid of the month
June 2020

Euastrum ansatum

Eu. ansatum is a rather large-sized Euastrum species from the group characterized by a deep, narrow median incision at the apex. Semicells are about pyramidal in outline with concave lateral sides. Just above the basal lobes there is often a rudimentary lateral lobe. The semicell centre is slightly inflated and the base of the semicell is marked by a distinct tubercle just above the isthmus. The chloroplast is provided with a single, central pyrenoid. In the Netherlands, Euastrum ansatum is of rather common occurrence in various kinds of acidic, oligo- to mesotrophic water bodies.

Empty cell of Euastrum ansatum in frontal view showing cell wall pores as well as a prominent supraisthmial tubercle at the base of each semicell.

Image © Marien van Westen.

SEM picture of Euastrum ansatum showing a finely wrinkled cell wall.