Image © Henk Schulp
St. diacanthum belongs to the section of Staurastrum species characterized by arm-like cell processes. It is closely related to St. paradoxum * , the type species of the genus Staurastrum. In apical view, the semicell body is 3- or 4-radiate, each of the angles being attenuated to form a rather long, dentate process tipped with some four stout spines. Characteristic of St. diacanthum is the presence of two extra large, spiny, dorsal dentations near the base of each process. In the Netherlands, St. diacanthum is of rather rare occurrence in acidic, oligotrophic bogs and moorland pools.
Image © Henk Schulp
Cell of St. diacanthum in apical view. Note the pair of furcate spines near the base of each of the three processes.
* Some authors consider St. diacanthum a variety of St. paradoxum