Staurastrum retusum W.B.Turner 1893

    Cells as long as broad, deeply constricted, sinus closed to major part widely opening from an acute-angled apex. Cells measure 22-29 µm in length, 24-27 µm in breadth, 5-8 µm broad at isthmus. Semicells more or less trapeziform, with straight to slightly concave apex and broadly rounded apices; cell wall finely scrobiculate, more at angles, triangular in apical view; chloroplast axile, one per semi cell with a central pyrenoid.