Image © Marien van Westen
Cosmarium conspersum (var. latum). Notice granulate semicells with pentagonal outline, the angles being broadly rounded.
Cell dimensions (L x B): 90 x 75 µm
Empty cell of C. conspersum showing regular, longitudinal series of coarse granules.
Cosmarium conspersum is a rather large-sized species somewhat resembling C. reniforme in that its cell wall is covered with coarse granules disposed in regular rows. Moreover, the apex of the cell sinus is distinctly widened. Whereas, however, semicell outline in C. reniforme is kidney-shaped, in C. conspersum it is subrectangular to (especially in var. latum) pentagonal. In the Netherlands, C. conspersum var. latum is occasionally met with in mesotrophic fens.
Image © Alfred van Geest
Another cell of C. conspersum. Notice cell sinus that is distinctly widened at the isthmus.
Imnge @Jan Šťastný
SEM image of C. conspersum