Sample populations of Usnea subfloridana and explanatory variables mean annual air temperature (‘Temp’) and geographical longitude of populations (‘Long’) in the bi-plot of the redundancy analysis (RDA) of the first and second axes. The shape of symbols indicates the geographical location of studied populations (square – south-eastern region of mainland, circle - western island and diamond – north-eastern region) and the size of symbols indicates the number of different alleles found in the studied populations.