Taxonomy and distribution of Lemanea and Paralemanea (Lemaneaceae, Rhodophyta) in the Czech Republic.

Traditionally, all freshwater representatives of red algae with uniaxial cartilagineous and pseudoparenchymatous thalli were placed in the genus Lemanea. Two subgenera of this genus were distinguished, Lemanea and Paralemanea. The recently proposed elevation of these subgenera to genera is fully justified and generally accepted. However, the increasing data from natural populations of Lemanea shows that not all the traditional diacritical features are reliable for distinguishing species. This paper presents the results of a research project on the morphological variability of Lemanea in the Czech Republic. Of the four species Lemanea fluviatilis and L. torulosa appear to be well-defined but there are no clear differences between Paralemanea annulata and P. catenata. A survey of taxa and key to species are presented.