Phylum: Charophyta   Family: Desmidiaceae

Cosmarium cedercreutzii R.L. Grönblad 1921

Since Grönblad (1921: p. 27, pl. 6:12-13) first described this desmid from Finland, it has been difficult to determine its distribution owing to probable confusion with Cosmarium crenatum and its varieties. It occurs with moss on wet rocks and similar habitats. In one cell, each semicell has a small scrobiculus centrally placed. This can only be observed in empty cells at deep focus so easily overlooked. Not previously reported. SEM imaging would be required to see it clearly.

References: 
Grönblad, R. (1921) New Desmids from Finland and Northern Russia with critical remarks on some known species
Kouwets, F.A.C. (in manuscript) European Flora of the Desmid Genus Cosmarium