The influence of different salinities on growth and morphological variability of a number of Phormidium strains (Cyanophyceae) in culture

Phormidium strains from freshwater- and marine habitats were submitted to culture experiments in media with different concentrations of seawater. The marine strains showed a greater halotolerance and less morphological variability than the freshwater ones. The results are discussed with regard to Drouets species concept within the Cyanophyceae.