Cell of Staurastrum pyramidatum in frontal view. Notice conical spines arranged in dense, concentric series around the basal semicell angles.
Cell dimensions (L x B): ca 65 x 55 µm
St. pyramidatum is a rather large-sized, solid built Staurastrum species. Its name suggests a pyramidal shape but actually the outline of the semicells is rounded trapezoid rather than pyramidal. The cell wall is densely and evenly beset with short, conical spines that are often locally doubled. In the Netherlands, Staurastrum pyramidatum is very rare, being only known from a single oligo-mesotrophic site in the province of Drenthe. Its distribution in Europe is mainly in upland and mountainous regions.
Image © Alfred van Geest
Cell of St. pyramidatum in rear view. Notice that part of the spines are doubled.
Image © Marien van Westen
Cell of St. pyramidatum in apical view. Notice straight sides and broadly rounded angles.