Observations on Euastrum gemmatum

Description: The cells are 1.25–1.55–(1.7) times longer than wide and.squarely shaped in the center section. Due to an emargination the lateral line of the shape shows two lobes. The vertex lobes are broadened towards the periphery, rounded on the lateral line and slightly concave in the center of the lobe. The cut in the middle of the cell is deep and peripherally widened. In the center of the cell halves there is a clear hump with small verrucae, on both sides of this hump there is a further, flat hump. This area together with the lateral lobes and the vertex lobes are clearly covered with tiny warts.

Dimension: Length 50–65–(70) µm, width 35–48–(52) µm.

Occurrence: Not rare also in weakly acidic ponds in the alpine regions up to an altitude of 2000 m.

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.