Taxonomic and biogeographical notes on Okavango desmids (Zygnematophyceae, Streptophyta)

In October 2007, a selection of water bodies in the Okavango Delta (Botswana) and the southwestern part of the Zambezi Basin (Namibia) were sampled for desmid algae. In this paper 27 taxa belonging to the genera Penium, Closterium, Pleurotaenium, Triplastrum, Tetmemorus, Euastrum and Micrasterias are separately discussed and figured. Five taxa are newly described: Closterium okavangicum, Tetmemorus euastroides var. africanus, Euastrum attenuatum var. groenbladii, Euastrum okavangicum and Euastrum sudanense. The names of five taxa are newly given or recombined: Euastrum africanum, Euastrum compereanum, Euastrum fritschii, Euastrum scottii and Micrasterias schmidleana. The majority of the taxa discussed can be characterized as African endemics.