Coelastrum pascheri sp. n., a new green alga from lakes of the Bohemian Forest

Coelastrum pascheri sp. n. is described. It is similar to Coelastrum morus W. et G. S. West sensu Skuja (1930) in the morphology of the free processes, but differs from it in cell size (it is significantly smaller, 13–16 µm) and in the number of cells in a cenobium (usually 4). The new alga was found in the littoral of some lakes: ?erné jezero (?erné Lake), Grosser Arbersee and Kleiner Arbersee in the Bohemian Forest (?umava, Böhmerwald) and also in Sphagnum within a small puddle in the Upolínová meadow in the Slavkovský les Mts.