Natural and cultivated poplars of Irkutsk Province and Buryat Republic

The study aimed at supposed area contact zone of Populus laurifolia and P. suaveolens. We looked for evidence of natural hybridization of the two species, along with the description of local ornamental cultivars which may be involved in these hybridizations, too. Species, cultivars and hybrids we identified by morphological characters traditionally used in poplar taxonomy. We found out that P. laurifolia did not grow in the studied area. Instead, we revealed a westward clinal variability of P. suaveolens characters towards P. laurifolia. Hybrids of three Siberian poplars, P. laurifolia, P. suaveolens and P. nigra dominate among cultivars. We found no evidence of numerous hybridization events between these cultivars and natural species in the area studied.

Morphological variability of leaves of Sorbus domestica L. in Croatia

The paper studies the morphological variability of the service tree populations in the continental and Mediterranean regions of Croatia. The inter- and intra-population variability, as well as eco-geographic population differentiation, was established on the basis of eight measured morphological characteristics of two types of leaflets (lateral and terminal) and two derived ratios, using descriptive and multivariate statistical methods. The conducted research established a high variability of morphological characteristics. In comparison with lateral leaflets, terminal leaflets showed a higher degree of variability for the majority of the studied variables. The differences between the trees within populations, as well as the differences between populations, were confirmed for all studied characteristics. The study also confirmed a trend of population variations according to the eco-geographic principle. Populations from climatically different and geographically distant habitats, in other words from the Mediterranean and the continental region, differed in the majority of studied characteristics. In addition to the established pattern of ecotypical variability between the continental and the Mediterranean regions, the clinal variability with regard to altitude and mean annual temperature was also confirmed. Small, although statistically significant clinal variability with regard to the longitude was recorded for two measured characteristics. The conducted study provided insights into the variability of the service tree populations in Croatia, which is a basis for further research that should be implemented in order to produce guidelines for the breeding and conservation of genetic resources of this rare and endangered noble hardwood species.