Phylum: Charophyta Family: Desmidiaceae
Staurastrum anatinum var. denticulatum G.M. Smith
The cell body and processes have pronounced spines, many bifurcate. Apparently this variety is more often found in circumneutral waters. Status unclear
References:
Smith, G.M. (1924) Phytoplankton of the Inland Lakes of Wisconsin, Part II: Desmidiaceae
Coesel, P.F.M. & Meesters, K.J. (2013) European Flora of the Desmid Genera Staurastrum and Staurodesmus