Image © Alfred vanGeest
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
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.
Image Frans Kouwets © Rijkswaterstaat
SEM picture of Cosmarium amoenum showing cell wall pores that are arranged in circles around the granules.