Description: The cells are 5–7 times longer than they are wide, uniformly curved and gradually narrow towards the broadly rounded cell ends, sometimes slightly swollen in the middle on the ventral side. The cell wall is very fine, sometimes barely noticeably striped and without girdle bands. The pyrenoids are numerous and, as one of the distinguishing features from the morphologically similar Closterium moniliferum (in which they are arranged in a row in smaller numbers along the cell axis), are scattered. The terminal vacuole contains numerous small crystals.

Dimension: Length (450)–500–800–(1100) µm, width (80)–85–100–(175) µm.

Occurrence:  Widely distributed in both slightly acidic and slightly polluted waters of all kinds, sometimes also in plankton.

Left: Original graphic by Prof. Lenzenweger.
Right: Photomicrograph by Prof. Lenzenweger. For microphotography, the microscope illumination was adjusted in such a way that as many features as possible that are important for species identification are prominently displayed.

Copyright by Prof. Rupert Lenzenweger, Ried im Innkreis, Austria.