I find Sporotetras polydermatica regularly but rarely in the Simmelried. The colonies should be about 20 X 30 µm according to Hindák (1978). This is also about the size of the colonies in my population with diameters of 20–70 µm (not squashed). The cells in my population were mostly between 8–10 µm long and oval. The chloroplast is cup-shaped (s. fig. 4) and I could observe one pyrenoid (s. figs. 1 and 4). The cells were irregularly distributed in the colony and surrounded by a concentrically layered envelope (s. figs. 3 and 4). Thus, all features agree with the descriptions of Kostikov et al. and of Hindak (who described it as Gloeocystis polydermatica).