Three cells of Cosmocladium constrictum interconnected by fibrillar strands. Notice the Actinotaenium-like, lobostelloid chloroplasts.

Cell size (L x B): 14 x 9 µm



Desmid of the month
February 2008

Cosmocladium constrictum

Unlike in Cosmocladium saxonicum colonies of C. constrictum usually number but a few cells. Obviously, the intercellular strands are extremely delicate so that large colonies are seldom built up. Separate cells of C. constrictum may be easily confused with those of given Actinotaenium species, in particular A. perminutum. From the Netherlands only a few records are known (some moorland pools in the province of Noord Brabant)  but likely, if only separate cells are encountered, it will be readily overlooked.  The herewith reproduced colonies originate from Thai samples.

A four cell colony of C. constrictum. Next to the (relatively thick) interconnecting strands numerous thinner, extracellular fibrils are to be observed, presumably mucilage extrusions from the cell wall pores.

Exceptionally large colony of Cosmocladium constrictum clearly showing some of the interconnecting strands.