Morphological variability of leaf and shoot traits of four barberry taxa (Berberis L.) from the Balkan Peninsula and Sicily

Leaf and shoot characteristics of the following four European barberry taxa from the Balkan Peninsula and Sicily were investigated in the present study: Berberis croatica, B. vulgaris, B. aetnensis and B. cretica. Analyses were based on 10 populations of B. croatica, five of B. vulgaris and two populations of both B. aetnensis and B. cretica. Populations were randomly selected within the natural distribution area of these species. Eight leaf traits, three shoot traits and the blade length/width ratio were analysed. Multivariate analysis (principal component analysis, canonical discriminant analysis and cluster analysis) distinguished B. cretica and B. aetnensis populations and, to a lesser extent, the populations of B. croatica and B. vulgaris. ANOVA showed that the analysed populations of both B. aetnensis and B. cretica were homogeneous within the species. All populations of both B. croatica and B. vulgaris showed different degrees of intraspecies variability. Lack of complete separation, the observed grouping of populations and high intraspecies variability in B. vulgaris and B. croatica may reflect the fact that the sampled B vulgaris and B.croatica populations were located at environmentally variable sites (unlike B. aetnensis and B. cretica), resulting in high phenotypic plasticity in those populations. Even though the observed patterns of morphological variation support the idea of four barberry taxa on the Balkan Peninsula and in Sicily, because of suspected adaptive phenotypic plasticity of the analysed Berberis taxa, the true taxonomic status of these taxa needs to be additionally confirmed by molecular methods.