Cell of Cosmarium amoenum in frontal view. Notice roughly elliptic cell outline and rather shallow sinus. Semicells with firm-lined cell wall and evenly distributed granules.

Cell dimensions (L x B): ca 50 x 30 µm



Desmid of the month
March 2015

Cosmarium amoenum

Cosmarium amoenum belongs to the group of Cosmaria characterized by a firm-lined cell wall fairly evenly provided with granules. Just above the isthmus those granules are usually arranged in two transversal series. Cell outline in C. amoenum is about elliptic with a rather shallow, narrowly open to almost closed sinus. In the Netherlands, C. amoenum is occasionally encountered in acidic bogs and moorland pools.

Cell of Cosmarium amoenum in apical view showing a broadly elliptic outline.

Cell of Cosmarium amoenum showing pattern of cell wall granules in more detail. Notice arrangement of isthmial granules in two transversal series.



SEM picture of Cosmarium amoenum showing cell wall pores that are arranged in circles around the granules.