Multivariate analysis of qualitative and quantitative data from algal commu
nities, collected at three coastal areas of the Aegean Sea in the upper inf
ralittoral zone, has been carried out using the PRIMER software. The aim wa
s to detect groups of species reflecting differences in environmental condi
tions. A multidimensional scaling of the results demonstrated the presence
of three different groups of Cystoseira species, corresponding to different
hydrodynamic conditions.