So far I have found Desmodesmus opoliensis in the plankton of the Oder only once, in May 2026. In the samples the specimens were only sparsely present. The species can be very easily recognized by the obliquely positioned middle cells. These bear only small spines or warts on their apices, while the apices of the outer cells are slightly bent outward and carry long, often curved spines. In my specimens the cells were about 25 µm long. The outer flanks of the cells were described as smooth by Komarek & Fott (1983). In my population, however, I was able to observe short sections of ribs near the cell ends. These were always shorter than 5 µm and in no case continuous over the entire cell length.