A morphometric study on Senecio erucifolius (Asteraceae) from Poland and its taxonomic implications

Abstract

Twenty-three populations of <em>Senecio erucifolius</em> were sampled to study morphological diversity of the species in Poland. A total of 690 shoots, leaves, capitula, flowers, and fruits were characterized in respect to 27 quantitative traits and were subjected to morphometric analyses. Principal component analysis made it possible to distinguish two groups of individuals, corresponding to two infraspecific taxa – <em>S. erucifolius</em> subsp. <em>tenuifolius</em> (19 populations) and <em>S. erucifolius</em> subsp. <em>erucifolius</em> (four populations). The characters of the greatest importance in differentiating these two subspecies included the length of the upper lobe of the middle leaf, the width of the upper lobe, the width of the longest lateral lobe, the width of the upper lobe at the base, and the length of the tubular flower. Six of the 27 morphological features significantly differentiated populations within subspecies <em>erucifolius</em> according to a stepwise discriminant analysis. The length of the middle leaf, length of the tubular flower and width of the upper lobe at the base contributed most to the discrimination between the investigated populations. The discriminant analysis also showed considerable morphological heterogeneity of the 19 populations classified as subspecies <em>tenuifolius</em>. Seventeen characters significantly differentiated the populations, with the length of the achene and the ratio between the length and the width of the achene as the most important ones.