New and rare species of Volvocaceae (Chlorophyta) in the Polish phycoflora

Seven species of Volvocaceae were recorded in the lower Vistula River and its oxbow lakes, including Pleodorina californica for the first time in Poland. Three species – Eudorina cylindrica, E. illinoisensis and E. unicocca – were found in the Polish Vistula River in the 1960s and 1970s, as well as at present. They are rare species in the Polish aquatic ecosystems. Three species are common both in the oxbow lakes and in the Vistula River: Eudorina elegans, Pandorina morum and Volvox aureus. New and rare Volvocaceae species were described in terms of morphology and ecology; also photographic documentation (light microscope microphotographs) was completed.