Observations on Cosmarium protractum var. procerum

Description: The cells are only little longer than wide. The cell halves form three lobes, the lateral lobes are unequally rounded off, whereby they appear gently rolling. The vertex lobes are slightly widened outwards, rounded off laterally and slightly concave in the center. The central cuts are deep and outward extended. At the basis of both cell halves there is a hump, which is covered with larger verrucae. The remaining cell wall is covered with smaller warts. The vertex view is oblong oval with one distinct surface bulg each at the sides.

Dimension: Length 87–90 µm, width 70–75 µm.

Occurrence: Well-known only from Greenland so far.

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.