This paper represents a floristic survey of the algal species in the order Chlorococcales (Chlorophyceae) from the São João River, Iguaçu National Park, Foz do Iguaçu, Paraná, Brazil. Samples were collected from June 2008 to May 2009 at three sampling stations along the riverbed. The phytoplankton material obtained with a 25 µm nylon plankton net was immediately fixed on Transeau solution. The qualitative analyses of the samples resulted in the identification of 28 taxa distributed among the families Hydrodictyaceae, Oocystaceae, and Scenedesmaceae. The most representative genus was Desmodesmus An, Friedl & Hegewald, with ten taxa. Chlorococcum Meneghini, nom. cons., Coelastrum Nägeli in Kützing and Sorastrum Kützing were the genera that least contributed toward the biodiversity, with only one taxon each.
Chlorococcales; Paraná State; river; taxonomy
