engleski

Morphological variability of Ulmus glabra Huds. in Lika and Gorski kotar, Croatia

The wych elm (Ulmus glabra Huds.) is a very valuable, noble hardwood species, taxonomically allocated to Ulmaceae family. It has northernmost distribution in relation to other European species of elm trees. According to phytocoenological determination, it is a typical tree of the zonal, mesophilic and rarely of the thermophilic beech forests, whereas it is a characteristic species in azonal communities of Tilio platyphylli-Acerion pseudoplatani alliance. The wych elm in Croatia occupies a specific ecological niche, and there is no possibility of creating hybrid swarms with the field elm, as is the case in the northern Europe. On the basis of 10 foliar morphological traits, by means of modern statistical methods, our goal was to assess interpopulation and intrapopulation variability of the wych elm. Material for the morphometric analysis was collected in 4 natural populations (Delnice, Vrbovsko, Otočac, Gospić) in the areas of Lika and Gorski kotar in Croatia. Although sampled populations were heavily compromised by the Dutch elm disease, our results suggest high variability of the observed morphological traits. Overall variability coefficient ranged from 11, 94 % for angle between the main leaf vein and the line defined by the leaf base, and the point of the leaf edge where leaf lamina is widest to 52, 94 % for the leaf base asymmetry trait. Partitioning of variance showed that differences among trees in a single population accounted for the most of variability determined, while the remaining component, the amount of variation attributable to differences among populations, was considerably smaller. From the UPGMA dendrogram it was evident that according to the researched leaf traits the most similar populations were Delnice and Vrbovsko, followed by population Otočac. The southernmost and geographically most distant population Gospić proved to be morphologically significantly different from the other three populations, which was particulary evident in relation to Delnice and Vrbovsko population.

Ulmus glabra; morphological variability; foliar traits; Croatia

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