Sex ratio and sexual dimorphism were studied in the dioecious tree Taxus baccata. We examined five populations of T. baccata in Poland and Ukraine to identify the differences between male and female individuals. The sex of all individuals, height and diameter, needle length and area, specific leaf area (SLA), the number of stomata rows, stomatal density, and content of carbon and nitrogen were measured to identify the differences between male and female individuals. The relationship between sex ratio and climatic conditions, age and population size were analysed using data collected from the field and the literature. Female trees were shorter than males, but needles of females were longer and had larger area. Although there were no differences among sexes in SLA, nitrogen and carbon concentration, we found a positive correlation between nitrogen concentration and SLA among females. The sex ratio changed with tree height within populations, and taller height classes were biased in favour of males. Regardless of population age, the percentage of females within populations was positively correlated with precipitation. Probably high reproductive effort caused female trees to lose in competition with males, and this loss may also be enhanced by lower drought tolerance in females and could contribute to risk of extinction for T. baccata. The continental geographic range of T. baccata may be restricted by limited occurrence of females, which demand higher water resources than males.

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Juniperus excelsa constitutes a precious woody species of high ecological value able to grow up to Mountain treeline around the Mediterranean. Nuclear microsatellites were used to shed light on genetic diversity and differentiation of different Mediterranean populations. This information is essential in planning conservation strategies and reforestation programs.

The phenotypic differentiation of Pinus mugo complex was verified using 31 populations of P. mugo sensu stricto, 11 of P. uncinata, five of P. uliginosa, one of the potential hybrids P. uliginosa £ P. mugo and three of P. sylvestris, the latter as a control. The 22 morphological and anatomical needle characteristics were measured and statistically examined to describe the taxa and the population within the taxa differentiation. All the taxa of the P. mugo complex differed significantly from P. sylvestris in most of the verified needle characteristics. Within P. mugo complex, populations of P. uncinata were clearly distinguished from P. mugo s. s. The population of potential hybrid origin was the most similar to P. uliginosa. Populations of the latter taxon were strongly differentiated; some of them were closer to P. uncinata, and others to P. mugo s. s. Within the whole sampled data, three geographic groups of populations were detected: the first included P. uncinata and two of P. uliginosa, the second contained East and South Carpathian P. mugo s. s. with the presumed hybrid population, and the third contained all the other populations of P. mugo s. s. and P. uliginosa. Within P. mugo s. s., the Sudetan populations formed a separate group. Pinus uncinata from the Pyrenees reflected a high level of differentiation. The marginal populations of this taxon (Cebollera, G udar, Massif Central) also differed from those in the Pyrenees. The phenotypic differentiation of taxa and populations appeared similar to that which was detected based on cpDNA markers.

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The main aim of the present study was testing the value of the morphological and anatomical characteristics of the needles in distinguishing Cedrus atlantica, C. libani and C. brevifolia. Nine populations were sampled in their natural habit and 25 characters were used to describe the variation of the brachyblast needles and to analyze the differences between species. The results indicated that morphological and anatomical needle characters provide valuable tools in discrimination of the taxa. The scored differences were statistically significant, as revealed in the Tukey's t test, discrimination analysis and hierarchical analysis of variation. The results support treating C. libani, C. atlantica and C. brevifolia as independent species.