Five species of Mallomonas (Synurophyceae) new to the algal flora of the Czech Republic.

Five new records of the scale-bearing chrysophytes Mallomonas multiunca, M. paxillata, M. portae-ferreae, M. prora and M. retifera are reported for the Czech Republic. M. multiunca was found in a mesotrophic oxbowlake of the river Vltava. M. paxillata, M. portae-ferreae and M. prora were found in a mesotrophic to eutrophic floodplain pool of the river Lužnice. M. retifera was recorded from alluvial pools associated with the Vltava and Lužnice rivers, respectively. Autecology and distribution of the species are discussed. Three of the species occur in temperate and subarctic regions, M. paxillata probably has a cosmopolitan distribution and M. portae-ferreae prefers warmer water, occurring most frequently in tropical to subtropical regions.