Cosmarium hostensiense. Notice elliptic cell outline and coarsely pitted cell wall.
Cell dimensions (L x B): 65 x 35 µm



SEM picture of C. hostensiense showing scrobiculae in detail.


SEM picture of C. hostensiense in (oblique) apical view. Notice that each scrobicle is provided with a single, central pore.



 


Desmid of the Month
October 2024

Cosmarium hostensiense


Cosmarium hostensiense a little bit resembles given forms of
C. pseudopyramidatum (desmid of June 2021) but semicells of C. hostensiense are semi-elliptic rather than pyramidal in outline. Most important differentiating characteristic in C. hostensiense is its coarsely pitted cell wall sculpturing. In the Netherlands, C. hostensiense is only known from a single, subatmophytic moorland site in the province of Drenthe. In 2024 it was encountered in a suchlike habitat in Belgian Flanders.


Another cell of C. hostensiense, basal angles in one of the semicells being a bit protracted.

Empty cell of C. hostensiense showing pattern of cell wal pits (scrobiculae).