Desmid of the month
July 2018

Staurastrum margaritaceum

Cell of S. margaritaceum somewhat resemble those of S. sexcostatum (desmid of December 2011) but are a bit smaller whereas their ornamentation is less marked. Moreover, the arm-like processes are inserted near the semicell apex giving rise to a more or less campanulate outline of the semicell body (versus about elliptic in S. sexcostatum). In apical view, semicells are 4- to 6-radiate. Processes are relatively short and ornamented with concentric series of granules. Semicells at their base often with a supraisthmial whorl of granules. In the Netherlands, S. margaritaceum is a common inhabitant of acidic, oligotrophic bogs and moorland pools.