Phylum: Charophyta Family: Desmidiaceae
Cosmarium pseudopyramidatum var. extensum (Nordstedt) Willi Krieger & Gerloff 1965
Since Cosmarium pseudopyramidatum was separated from C. pyramidatum it has spawned several varieties. Kouwets (in manuscript) is currently working to clarify the situation and it’s likely this variety with be elevated to species level. The main distinctions are a truncate apex and a much greater quotient value. Because of confusion with similar species, its distribution is largely unknown.
Krieger, W. & Gerloff, J. (1962-9) Die Gattung Cosmarium
Kouwets, F.A.C. (in manuscript) European Flora of the Desmid Genus Cosmarium