Phylum: Charophyta   Family: Desmidiaceae

Staurastrum crenulatum (Nägeli) Delponte 1877

Found in circumneutral, mesotrophic waters. Coesel & Meesters (2013) note the taxonomic concept of S. crenulatum is rather obscure, due to a lack of clarity of the illustrations by the original authors, and therefore have adopted the West's (1899) concept. Due to this lack of clarity, distribution is unclear.

References: 
Delponte, G.B. (1873, 1877) Specimen Desmidiacearum Subalpinarum.
West, G.S. (1899) On Variation in the Desmidieæ, and its Bearings on their Classification.
Coesel, P.F.M. & Meesters, K.J. (2013) European Flora of the Desmid Genera Staurastrum and Staurodesmus.