Phylum: Charophyta   Family: Desmidiaceaa

Cosmarium suborthogonum Raciborski

This was made a variety of Cosmarium impressulum by Taft (1945) based on the papillae in the centre of the semicells. It has little in common with that species, including being of a smaller size, hence Kouwets (in manuscript) proposes reinstating it as a separate species. Found in circumneutral waters, its status in largely unknown

References: 
Kouwets, F.A.C. (in manuscript) European Flora of the Desmid Genus Cosmarium
John, D.M. & Williamson, D.B. (2009) A Practical Guide to the Desmids of the West of Ireland