Within-species variation among populations of the <i>Carex flava</i> complex as a function of habitat conditions

<p><b><i>Background</i></b>: Variable habitat conditions contribute to morphological variability that plays a substantial part in evolution of plants. Understanding the extent of phenotypic plasticity has important implication for assigning individuals to taxa.</p> <p><b><i>Aims</i></b>: I analysed morphological variability among populations within species of the <i>Carex flava</i> group and tested to what extent morphological variability was associated with habitat conditions.</p> <p><b><i>Methods</i></b>: A total of 571 specimens from 20 populations of four species from the <i>C. flava</i> complex were sampled in Poland and tested by Discriminant Function Analysis (DFA). The relationship between morphological characters and habitat factors was explored by means of the redundancy analysis (RDA).</p> <p><b><i>Results</i></b>: Variability of the generative and vegetative traits was fairly similar in <i>Carex lepidocarpa, C. flava</i> and <i>Carex demissa</i>, while it was somewhat higher in <i>Carex viridula</i>. The morphological traits were mostly related to soil organic matter content, calcium and carbonate, as well as to habitat fertility (C:N ratio), elevation and habitat disturbance. The results obtained do not support the separation of <i>C</i>. <i>viridula</i> var. <i>pulchella</i> from <i>C. viridula</i> var. <i>viridula</i>.</p> <p><b><i>Conclusions</i></b>: Phenotypic variability in the species of the <i>C. flava</i> complex is related to habitat conditions and this can lead to the differentiation of morphotypes within species.