inner cells cylindrical with tapered and rounded ends.
at the apices of the inner cells with two spines diagonally opposed to each other
marginal cells slightly convex on contour side
marginal cells with a curved spine at each apex
in the equatorial zone of each cell an additional spine on one side of coenobium
cell wall smooth, without ornamentation
each cell with one pyrenoid
I have found Desmodesmus asymmetricus so far exclusively in the Simmelried. The species occurs regularly, but never in large numbers. Mostly I find single, isolated specimens. Desmodesmus asymmetricus can be identified by the spines in the equatorial zone of the coenobium (s. fig. 1b) and by the convex shape of the outer cells (s. fig. 1a).
Fig. 1 a-b:Desmodesmus asymmetricus. L = 12 µm (of coenobia). Two focal planes of a slighty squashed specimen. Note the convex contour of the marginal cells (arrow). ES = equatorial spines, DS = diagonally arranged spines of the inner cells. PY = pyrenoid. Obj. 100 X.