Cosmarium notabile
image © Alfred van Geest

Cosmarium notabile. Notice trapeziform semicells with some 14 marginal crenations. Cell dimensions (L x B): 36 x 27 µm.



Cosmarium notabile
image © Alfred van Geest (mouse-over)

Empty semicell of C. notabile showing some intramarginal series of granules.



 


Desmid of the Month
April 2026

Cosmarium notabile


Cosmarium notabile is a little characteristic, so easy to confuse Cosmarium species. In a way, it may be considered an impoverished form of C. rostafinskii . As compared to that latter species, cells of C. notabile are smaller and cell wall ornamentation is less pronounced. In particular, a supraisthmial band of longitudinal series of granules, characteristic of C. rostafinskii, is hardly or not developed. In the Netherlands, C. notabile is of occasional occurrence on wet substrates and in ephemeral puddles.

Cosmarium notabile
image © Alfred van Geest

Semicell of Cosmarium notabile in apical view showing a slight median inflation.


Cosmarium notabile
image © Alfred van Geest

SEM picture of Cosmarium notabile Notice slight traces of a transversal, supraisthmial band of granules only being present in the lower semicell.