Phylum: Charophyta   Family: Desmidiaceae

Cosmarium trilobulatum f. retusum Gutwinski 1890

The original description and figures of the nominate variety lacks clarity and there is some doubt as to its true identity. The forma retusum is thought by Kouwets (in manuscript) not to belong here and he is proposing elevating it to species rank. Dutch material has be found occurring atmophytically on wet sand. The Haclait finds (confirmed by Frans Kouwets) were from a shall boggy pool.

References: 
Kouwets, F.A.C. (in manuscript) European Flora of the Desmid Genus Cosmarium
Coesel, P.F.M. & Meesters, K.J. (2007) Mesotaeniaceae and Desmidiaceae of the European Lowlands
Prescott, W.G., et al. (2001 reprint) A Synopsis of North American Desmids. Part II, Desmidiaceae: Placodermae, Section 3