Survey of genera Desmidiaceae (except Cosmarium) in a tributary of Itaipu Reservoir. It carried out it qualitative analysis of 60 samples collected in the period from July 2003 to June 2004. Forty-one species, ten varieties which are not the typical of its respective species and an another not typical species were also identified. The Desmidiaceae were represented by the genera: Actinotaenium (1), Closterium (3), Euastrum (5), Micrasterias (5), Octacanthium (1), Onychonema (1), Penium (1), Pleurotaenium (2), Spondylosium (2), Staurastrum (14), Staurodesmus (5) and Xanthidium (1). Staurastrum was the most presented genus, contributing with 34% of the total wealth. The least presented genera were: Actinotaenium, Octacanthium, Onychonema, Penium and Xanthidium, with one species each totaling 12%. Micrasterias truncata (Corda) Brébisson ex Ralfs var. pusila G.S. West was found in all stations of collection.
Brazil; desmids; taxonomy; Zygnemaphyceae
