Diversity of Salix reticulata L. (Salicaceae) leaf traits in Europe and its relation to geographical position

Abstract

Leaves of 279 individuals of Salix reticulata, collected from eight populations in contemporary isolated parts of the species range in Europe, and for comparison, from one population in the Rocky Mountains, were measured and analysed statistically. The characters describing the leaf size were more variable than the shape characters. All size characters were statistically significantly correlated, as well as they positively correlated to the northern latitude and eastern longitude, and negatively related to the altitude. The shape describing characters were assumed to be independent of the environmental conditions. Relations between samples based on multivariate analyses showed that the biogeographical structure of the studied S. reticulata populations is not quite clear. The present results suggest early transatlantic migrations of the species, possibly at least two migration routes to Scandinavia, and close relations between the Tatra Mountains, the Alps and the Western Scandinavia.

Keywords:

• Arctic-alpine plants
• leaf shape
• leaf size
• morphological variability
• Salix reticulate
• statistical analyses

Acknowledgements

I would like to thank Amelia Lewandowska for her great help in the measurement procedures and Adam Boratyński, Krystyna Boratyńska, Anna Ronikier and Michał Ronikier for the material collection. I am also grateful to Jason Sinicki and Alison Cowper for proofreading. The collection of the part of the material was possible thanks to the financial support of Kazimierz Wielki University in Bydgoszcz, Poland.