Image © Marien van Westen
Staurastrum hirsutum. Notice spiny semicells, about trapeziform in outline.
Cell dimensions (L x B): ca 45 x 35 µm
St. hirsutum is a triradiate, spinous Staurastrum species that somewhat resembles St. brebissonii but differs in having relatively longer cells and semicells that are trapeziform instead of elliptic-rhomboid. Moreover the two species differ in ecology. Where St. brebissonii is characteristic of various mesotrophic, circumneutral to slightly acidic habitats, St. hirsutum is mainly encountered in oligotrophic, distinctly acidic bog pools. In the Netherlands, St. hirsutum is rather widely distributed in the eastern and southern part of the country.
Another cell of Staurastrum hirsutum showing its 3-radiate configuration, cell surface being equally set with rather short spines.