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Rhododendron myrtifolium and R. ferrugineum are small, shrubby plant species that are morphologically similar to each other. They both grow on siliceous substrates in the subalpine belt of European mountains. In the present study, leaves and capsules from 11 populations of R. myrtifolium from the Carpathians were compared with those from 13 populations of R. ferrugineum from the Alps, Pyrenees and Sudetes. Fourteen leaf characteristics and 12 capsule characteristics of were analysed using ANOVA, discrimination analysis, principal component analysis and cluster analysis with agglomeration and the K-means method. All of the tested characteristics differed significantly between species, with the highest level of discrimination from the measured leaf traits. Less discriminatory were the proportions of the measured leaf features. According to the analyses, the populations of the two species were clearly separated, but individuals were partially intermixed. The similarities of the species may indicate a late divergence event, probably no earlier than the Pliocene. During the glacial cycles of the Pleistocene, populations of the two species may have mixed again. This may explain the presence of single individuals with R. myrtifolium morphology in some alpine R. ferrugineum populations and vice versa. The two species can be treated as another example of Carpathian–Alpine vicariance.

Vietnam is one of the main centers of generic diversity for Juglandaceae worldwide. In this study, we present for the first time a province-wide distribution of all 3 subfamilies, 7 genera, and 11 Vietnamese species, and give an update on the habitats of all Vietnamese Juglandaceae species, their uses, and current threats. Juglandaceae are found throughout Vietnam. However, most species occur predominantly in the northern part of the country between 600 and 1200 m. Some taxa range is found extensively from sea level up to 2,500 meters above sea level. According to the IUCN Red List, Rhoiptelea chiliantha, Carya sinensis, and Pterocarya tonkinensis are threatened while Engelhardia spicata, E. serrata, Alfaropsis roxburghiana, Pterocarya stenoptera are classified as least concerned. Carya tonkinensis is threatened locally, and Engelhardia spicata var. colebrookiana and Platycarya strobilacea merit “threatened” designation in Vietnam’s Red Data Book. The most frequent threats are logging, land-use change, and habitat destruction due to artificial wood plantations or road construction. Until now, no conservation measures have been applied for any of the species in Vietnam, although some species occur in national parks. Our study gives an important update on the current diversity and distribution of Juglandaceae in Vietnam.We point out the need for a correct assessment of the threat status of various species on a national and international scale to protect the rarest and most endangered of them. Further research, the use of various forms of protection of individual taxa and/or their habitats, and drawing the attention of an international group of researchers to the urgent need to work together to protect biodiversity in Vietnam hot spots are necessary.

Pterocarya fraxinifolia, native to the southern Caucasus and adjacent areas, has been widely introduced in Europe. In this study, we investigate the following: (1) How did its current distribution form? (2) What are the past, current, and future suitable habitats of P. fraxinifolia? (3) What is the best conservation approach? Ecological niche modeling was applied to determine its climatic demands and project the distribution of climatically suitable areas during three periods of past, current, and future (2070) time. Then, an integrated analysis of fossil data was performed. Massive expansion of Pterocarya species between the Miocene and Pliocene facilitated the arrival of P. fraxinifolia to the southern Caucasus. The Last Glacial Maximum played a vital role in its current fragmented spatial distribution in the Euxinian and Hyrcanian regions with lower elevations, and Caucasian and Irano-Turanian regions with higher elevations. Climatic limiting factors were very different across these four regions. Future climate change will create conditions for the expansion of this species in Europe. Human activities significantly decreased the suitable area for P. fraxinifolia, especially in the Euxinian, Hyrcanian, and Irano-Turanian regions. Considering genetic diversity, climate vulnerability, and land utilization, the Euxinian, Hyrcanian, and Irano-Turanian regions have been recognized as conservation priority areas for P. fraxinifolia.

No evidence of coordination between leaf hydraulic function and stomatal characteristics was observed in young hybrid aspen stands attributable to the near-anisohydric behaviour and the fast-growing nature of this species. Within forest canopies, there are environmental gradients that enhance water losses in the direction of treetops. Therefore, the foliar morpho-anatomical plasticity, which allows plant acclimation to environmental variations, is of great importance, but empirical information about the relationship between leaf structural and functional traits is inconsistent, varying with ecological requirements and the life strategy of the species. In this study, leaf hydraulic conductance, anatomical structure, and stomatal morphology were investigated in young hybrid aspen (Populus tremula × P. tremuloides) stands to elucidate the coordination between structural and hydraulic traits within the canopy. Stomatal size and density demonstrated opposite trends with respect to leaf location, leading to a relatively uniform spatial distribution of potential gas exchange capacity in the canopy. The hydraulic system of branches was adjusted to maximise the potential water supply in the midcanopy, containing nearly half of the trees’ total photosynthetic surface. Most vascular traits in both the petioles and laminae demonstrated stronger development towards the treetop that should enhance the water supply of the upper foliage, which is exposed to higher irradiance and atmospheric evaporative demand. Small increases in the total vein density expressed per unit lamina area in the upper canopy could not compensate for substantial leaf thickening, resulting in decreased vein density expressed per unit lamina volume and increasing the resistance of the leaf extravascular pathway. No solid evidence of coordination was found between leaf hydraulic function and stomatal characteristics attributable to the near-anisohydric behaviour and the fast-growing nature of this species.

Pinus sylvestris from the Iberian Peninsula was biometrically compared, using needle morphological and anatomical characteristics from 15, and cone morphological characteristics from nine natural populations. Samples of Scots pine represent subspecies nevadensis and varieties pyrenaica, catalaunica, and iberica. Analyses included 25 needle and 17 cone characteristics and numerical methods (principal component analysis, discrimination analysis, agglomeration on Euclidean/Mahalanobis¿ distances). A strong differences were detected between P. sylvestris subsp. nevadensis when compared to varieties pyrenaica and iberica, and a closer relationship to var. catalaunica in needle characteristics. In cone characteristics, the differences were at a similar level. Alien individuals were found within every taxon and population. Samples from the southern part of Sistema Central had the highest level of alien individuals. The geographic pattern of differentiation resembles patterns previously revealed using molecular and isoenzymatic markers. We could not detect characteristics specific to either P. sylvestris subsp. nevadensis or varieties of P. sylvestris subsp. sylvestris., This research was financially supported by the Polish Ministry of Science and Higher Education (Contr. No. NN303 360535) and partly by the Institute of Dendrology PAS under statutory activity., Introduction Material and methods Material Measurement procedures Statitstical analyses Results Variation and correlation of characteristics Differences between taxa Discusion Conclusion Supplemental material Disclosure statement Additional information References

The relict tree species Zelkova abelicea and Z. sicula (Ulmaceae) occur in Crete and Sicily, respectively. Zelkova abelicea grows in approximately 40 localities in the mountains of Crete, while Z. sicula has been found in only two stands in Sicily. We compared 25 morphological characters of the leaves of both species and used statistical methods (Tukey’stest, discrimination analysis, principal component analysis, agglomeration) to reveal the differences between these two species, their relation to Z. carpinifolia (the third Zelkova south-west Eurasian species), and between the leaves from different shoot types. Our study represents the first comparative biometric analysis of the three Zelkova species localized in the western edge of the current geographic range of the genus. We found that the species differed from each other both, in terms of leaf form characters and level of leaf variation. Zelkova carpinifolia was clearly different from Z. abelicea, while the two populations of Z. sicula, SIB and SIA, were more similar to Z. carpinifolia and Z. abelicea, respectively. The latter finding supports the results of recent molecular studies suggestingt he hybrid origin of Z. sicula. Zelkova abelicea, Z. sicula and Z. carpinifolia differ each other in the leaf characteristics and level of phenotypic variation.

An uncontrolled, natural episode of flooding with waters contaminated with As-rich pyrite (FeAsS) particles caused serious ecological damage leading to necrosis of plants growing in a fresh wet meadow located in an area characterized by unique geological structures rich in arsenopyrites. One of the few plant species capable of surviving this event was Salix aurita L., which grew in numbers in the analyzed area, but individual plants were affected differently by toxic flooding. No significant phenotypic changes (Group I), through partial leaf and/or stem necrosis (Group II) up to necrosis of the whole parental plant and root suckers (Group III), were observed for various willow clumps. These varied phenotypic responses of S. aurita to As-rich sediments were compared with the biochemical status of the foliage of willow trees, and with their rhizosphere physiological parameters. Our in situ study revealed that the biochemical status of leaves reflects the phenotypic damage incurred by adult willows growing in their natural environment and affected by the flooding. In leaves of willows with increasingly negative phenotypic changes (Groups I → II → III) as well as increasing levels of reactive oxygen species, malondialdehyde and decreased levels of glutathione and thiol groups were detected. Phytochelatins, commonly considered major As chelators, were not detected in S. aurita leaves. Despite a decrease in the size of leaves with the intensity of tree damage, all leaves expressed a normal level of leaf pigments. Phenotypic changes observed for particular willow clumps were only partly related to soil As levels. Moreover, As and S (but not Fe) foliar levels were related but did not correspond strictly with foliar biochemical features, or with soil As levels, soil pH or soil microorganismal activity, with the latter two drastically decreased in the rhizospheres of willows from Groups II and III.

The genus Zelkova (Ulmaceae) has occurred in Europe and Southwest Asia since the Eocene represented mostly by the fossil-species Z. zelkovifolia. Currently, relict populations of Z. abelicea, Z. sicula and Z. carpinifolia can be found in Crete, Sicily and the Euxino-Hyrcanian province, respectively. To reveal relationships between extinct and extant Zelkova species, we compared fossil Miocene leaves of Z. zelkovifolia and leaves of extant species using morphological leaf characteristics and statistical methods (Tukey’s test, discrimination analysis, principal component analysis, agglomeration). The fossil leaves of Z. zelkovifolia appeared more variable and generally intermediate between all three extant species. The lowest level of significant differences was found between Z. zelkovifolia and Z. abelicea in the leaves from fertile shoots and between Z. zelkovifolia and Z. sicula leaves from vegetative long shoots. The intermediate positions of fossil leaves of Z. zelkovifolia between leaves of Z. abelicea, Z. sicula and Z. carpinifolia could indicate that the extinct species was an ancestor of all three extant taxa. Consequently, this result suggests divergence between Z. abelicea, Z. sicula and Z. carpinifolia no earlier than the late Miocene and/or during the Pliocene. Supplemental data for this article is available online at https://doi.org/10.1080/11263504.2022.2036849.

Pterocarya fraxinifolia (Poir.) Spach (Juglandaceae) is a model relict tree species native to South Caucasus and is a typical element of threatened riparian forests. Intensive land transformations, which are common in Transcaucasia, have resulted in loss of natural habitat and population decline of the species. One of the methods of ex situ conservation is seed banking. Cryopreservation in liquid nitrogen (−196 °C) is of particular interest, as it allows safe preservation of valuable plant genetic resources. However, the feasibility of seed cryopreservation is related to the desiccation tolerance and intrinsic composition of the seeds. In this study, we examined the physiological traits of Pterocarya fraxinifolia seeds, for which desiccation tolerance is unknown or controversial, and their feasibility for cryopreservation. Additionally, we tested stratification methods for dormancy assessment. Results showed that seeds survived desiccation to a moisture content of 2.8% with a germination rate of 64%. Stratification at a temperature of 3 °C for 8 weeks proved to be both fast and effective. Seed moisture content ranging from 2.8% to 18.1% was determined to be safe for cryopreservation. There was no difference in seedling emergence in seeds stored for 1 year regardless of the storage temperature (−3, −18, or −196 °C). Based on our results, Pterocarya fraxinifolia seeds can be classified as orthodox. This study demonstrates for the first time the feasibility of cryopreserving Pterocarya fraxinifolia seeds.

Scots pine (Pinus sylvestris L.) and the taxa from the P. mugo complex can hybridize in the contact zones and produce fertile hybrids. A unique example of an early Holocene relict population of P. sylvestris and P. uliginosa (a taxon from the P. mugo complex) growing on the tops of Jurassic sandstone rocks is located in Błędne Skały (Sudetes). Phenotypically, there are trees resembling P. sylvestris, P. uliginosa and intermediate forms between them. We expected that some of P. sylvestris and/or P. uliginosa-like trees could be in fact cryptic hybrids resembling one of the parental phenotypes. To address this question, we examined randomly sampled individuals, using a set of plastid (cpDNA), nuclear (nDNA) and mitochondrial (mtDNA) markers as well as biometric characteristics of needles and cones. The results were compared to the same measurements of allopatric reference populations of the P. sylvestris and the P. mugo complex (Pinus mugo s.s, P. uncinata and P. uliginosa). We detected cpDNA barcodes of the P. mugo complex in most individuals with the P. sylvestris phenotype, while we did not detect cpDNA diagnostic of P. sylvestris within P. uliginosa-like trees. These results indicate the presence of cryptic hybrids of the P. sylvestris phenotype. We found only three typical P. sylvestris individuals that were clustered with the species reference populations based on needle and cone characteristics. Most trees showed intermediate characteristics between P. sylvestris and P. uliginosa-like trees, indicating intensive and probably long-lasting hybridization of the taxa at this area and subsequent gene erosion of parental species.

We used 39 morphological and anatomical needle traits in the biometric comparisons Abies nebrodensis with A. alba and A. cephalonica. The multivariate analyses were utilised and a closer relationship of A. nebrodensis to A. cephalonica than to A. alba was detected, in contrast to what has been shown for cone characteristics.

Aim: To establish a complete database of Juglandaceae at a spatiotemporal scale and develop a phylogeographic framework with which to elucidate the distributional patterns, diversity patterns, origins, evolution, and conservation priority regions of this family. Location: Worldwide. Taxon: Walnut family (Juglandaceae). Methods: Data on the distribution of all the extant and fossil species of Juglandaceae were collected, followed by analyses of its latitudinal distribution, elevational distribution, and species and generic diversity. Furthermore, based on all genera and 87% of the species, we reconstructed phylogenetic relationships, estimated divergence times, calculated phylogenetic diversity and inferred ancestral distributions. Results: Extant Juglandaceae (10 genera and 60 species) are mainly distributed in eastern Asia and North America (principally between 20 and 40°N). Tropical Juglandaceae mainly inhabit mountainous areas higher than 1,000 m, especially in the New World. Southwest China and northern Vietnam are characterized by high species, generic and phylogenetic diversity. The United States of America has only high species diversity. The area of origin of Juglandaceae was North America and Europe in the early Eocene, and its widespread dispersal mainly occurred between 13 and 26 Ma. Main conclusions: The members of Juglandaceae inhabit areas with temperate climatic conditions. The diversification centre has shifted intercontinentally from North America and Europe to Southwest China and northern Vietnam, which are identified as conservation priority regions. The high-latitude cooling during the Oligocene followed by a long-term stable warmer climate in the early and middle Miocene drove the southward translocation of the family. © 2019 John Wiley and Sons Ltd

The firs (genus Abies, Pinaceae) species are a diverse and ecologically and economically important forest trees. In the Mediterranean and Central Europe, the genus Abies comprises twelve taxa with only partially resolved systematic statuses, and it has been classically divided into the sections Piceaster (fir-type `ancestral¿ group) and Abies (fir-type `modern¿ group). We expected that the simultaneous use of nuclear microsatellite (nSSR) markers and a set of morphological and anatomical needle characteristics would clarify the taxonomy and biogeographical history of the genus. Additionally, the level of genetic diversity for particular taxa was estimated. The highest level of genetic diversity was observed in the Balkans. The hypothesis of a decreasing level of diversity from east to west was confirmed. According to our results, the `ancestral¿ section Piceaster is well distinguished from the `modern¿ section Abies. The differentiation of `modern¿ Abies indicated the separation of A. alba, A. nebrodensis, A. cephalonica and A. cilicica, supporting the species status of these taxa. However, admixture between populations and taxa was detected, possibly because of crossbreeding between firs and ancient hybridization events. Anatolian A. equi-trojani, A. bornmuelleriana and A. nordmanniana were closely related and exhibited the highest level of admixture within populations, possibly because of intensive past migrations and crossing, supporting their subspecies taxonomic status. Gene exchange was also detected for some populations of A. cilicica, which are currently spatially isolated from taxa of the A. nordmanniana group. The differentiation detected within A. cilicica supported its subdivision into subsp. cilicica and subsp. isaurica. The same processes are responsible for differences between populations of A. cilicica subsp. cilicica from the Taurus and Lebanon Mountains., This research was funded by the National Science Centre (NCN) of Poland (project number N N303 412136) and partly by the Institute of Dendrology, Polish Academy of Science., Keywords 1. Introduction 2. Materials and methods 3. Results 4. Discussion 5. Conclusion Author contributions Declaration of Competing Interest Acknowledgements Appendix A. Supplementary material References

Juniperus drupacea is a unique relict species found in the mountains of southern Greece, southern Turkey, and western Syria and Lebanon. The aim of this study was to describe the natural range of this juniper by determining the current locations of its populations and to predict a theoretical range for the species based on current, past, and future climatic conditions. We used data from the literature, herbarium materials, and our unpublished field notes (about 500 georeferenced points in total) to determine the current natural distribution of J. drupacea (realized niche). To predict suitable conditions with the program MaxEnt, we used data from the WordClim database, which allowed estimation of the potential niche. The potential niche of J. drupacea was much wider during the Last Glacial Maximum (LGM) and was severely restricted during the Eemian interglacial period. Depending on the climate scenario, this species could become endangered in the future due to climate changes. Considering the relatively restricted geographic range of J. drupacea and the decreasing numbers of localities where it is found, conservation strategies should be adopted to allow for preservation of its genetic and morphological diversity., The study was financially supported by the Institute of Dendrology of the Polish Academy of Sciences, Kórnik, Poland, and by the Polish Ministry of Science under grant no. NN303153037.

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 co...

The study investigated the effects of exposure to increased relative air humidity (RH) on stomatal morphology and sensitivity to stomata closure inducing stimulus (low RH) in hybrid aspen (Populus tremula L. × P. tremuloides Michx.) coppice growing in field conditions. Artificially elevated RH reduced air vapour pressure deficit by 5%–10% and altered stomatal sensitivity; trees grown under high RH exhibited stronger stomatal response to decreasing air humidity. We found no difference in mean stomatal pore length between treatments and a small decline in stomatal density under humidification. The lack of correlation between stomatal sensitivity and morphological traits suggests that stomatal sensitivity was unaffected by stomatal morphology. In light of rising atmospheric humidity predicted for high latitudes, strict stomatal control over water loss might be beneficial for trees if drought events become more frequent in the future. However, our experiment revealed that about two-thirds of the leaf-to-air vapour pressure difference (VPDL) response curves demonstrated the opposite pattern, i.e., stomatal opening in response to increasing VPDL. Strict stomatal regulation is probably not beneficial to fast-growing aspen coppice under low RH, as this trait may restrict their carbon gain and growth rate.

Riparian trees, especially relict trees, are attractive and important for research to understand both past and recent biogeographical and evolutionary processes. Our work is the first study to elucidate the genetic diversity and spatial genetic structure of the canopy-dominating riparian (Juglandaceae) along two altitudinal gradients in different river systems of the Hyrcanian forest, which is one of the most important refugium of relict trees in Western Eurasia. Altitudinal gradients were chosen along two river systems at 100, 400 and 900 m a.s.l. Leaf samples were collected from 116 trees, and the genetic diversity was evaluated with eight SSR markers. Overall, 39 alleles were identified for all of the populations studied. The observed heterozygosity (Ho) varied from 0.79 to 0.87 (with a mean of 0.83). The results of the AMOVA analysis indicated that the variation within populations was 88%, whereas the variation among populations was 12% for all of the gradients. A structure analysis indicated that 93% of the trees were grouped in the same gradient. The genetic distance based on Fst confirmed the structure result and indicated a high rate of gene flow among the investigated populations. Based on high gene flow (low differentiation of the population along the same river) and the clearly distinct genetic structure of the investigated gradients, it can be concluded that rivers are the main seed dispersal vector among populations. The genetic diversity of did not show any trend from upstream to downstream. The high level of gene flow and uniform genetic diversity along each river suggest the “classical” metapopulation structure of the species. Pterocarya fraxinifoliaP. fraxinifoliaP. fraxinifolia

Divergence in genetic as well as phenotypic structures can be expected in species with disjunctive geographic ranges and restricted gene flow among isolated populations. Dwarf mountain pine has such a disjunctive geographic range in the mountains of Central Europe. We hypothesised that populations of Pinus mugo from the Giant Mts. differ from Alpine and Carpathian populations to a greater extent than differentiation within these regions; furthermore, these differences would be detectable at both the genetic and phenotypic levels. To verify this hypothesis, the diversity and differentiation within and among eleven populations from the Giant Mts., Carpathians and Alps were analysed using 19 isozyme isozyme loci, 17 needle and 15 cone morphological characters. Moreover, the data on 10 chloroplast microsatellites used in the previous study, were reanalysed. The differences between the three regions were greater than among populations within them. The microsatellites and isozymes clearly differentiated between regions, while in the multivariate analyses of cone and needle characters the Alpine and Carpathian populations were intermingled but distinct from those sampled in the Giant Mts. The significant genetic structuring among regions may result from an ancient fragmentation and long lasting geographic isolation between the Giant Mts., Alps and Tatras. The populations from the Giant Mts., the northernmost within the geographic range of P. mugo, presented lower level of genetic variation then those from the Alps and Carpathians. The pattern of genetic structure observed in dwarf mountain pine may be characteristic of wind-pollinated trees with a disjunctive geographic distribution

Despite Juniperus spp. being an important component of Mediterranean arid and semi-arid ecosystems, there is a lack of complex studies on their biogeographical patterns. Using 16 morphological cone and seed traits and three nuclear microsatellite markers, we investigated the morphological and genetic variability of seven Mediterranean and Macaronesian Juniperus taxa (J. oxycedrus ssp. oxycedrus, J. oxycedrus ssp. badia, J. brevifolia, J. cedrus, J. deltoides, J. macrocarpa and J. navicularis) to identify biogeographical trends and interspecific genetic relationships. The highest gene diversity was measured in J. oxycedrus ssp. oxycedrus (HE = 0.716) and the lowest in J. brevifolia (HE = 0.441). The west Mediterranean was characterized by a higher level of genetic diversity than the east Mediterranean. A lack of significant genetic differences between European and African populations of J. oxycedrus suggests that the Strait of Gibraltar was not a significant barrier to gene flow, but has promoted some morphological differentiation. The genetic and morphological results strongly support the recognition of J. macrocarpa, J. navicularis and J. deltoides at the species rank, whereas J. oxycedrus ssp. badia should be included in J. oxycedrus. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 174, 637–653.

9 p., The aim of this study was the biometrical comparison of Abies pinsapo Boiss., Abies maroccana Trab. and Abies tazaotana Côzar ex Villar from Spain and Morocco. The morphological and anatomical analysis of the needle characters of these firs revealed significant taxonomic differences. The results showed considerable distances between regions and very small differences among the Moroccan fir taxa. The examination of the needles and earlier genetic analysis did not provide evidence for distinguishing A. tazaotana at the species level

Zelkova carpinifolia is a relict tree occurring in refugial zones of south-western Eurasia. The main aim of the study was the biometrical comparison of the leaf characteristics of the species sampled in three regions of Transcaucasia. We aimed to test the hypotheses that (1) leaves from vegetative (L) shoots would be larger and more variable than those from fertile (S) shoots, (2) the leaves from the same shoot type express geographic patterns of morphological differentiation, similar to pattern described for genetic markers and (3) to verify the systematic position of Z. hyrcana and Z. carpinifolia subsp. yomraensis. The plant material was collected from 5 populations of Z. carpinifolia, one of Z. hyrcana and one of Z. carpinifolia subsp. yomraensis. The total 1482 leaves, 713 from L- and 769 S-type were measured using 26 characters. Our results show very high level of differences between leaves from the L- and S-type of shoots. The majority of leaf characters did not reveal dependence neither on geographic latitude, longitude and altitude nor on the basic climatic data. The results of multivariate analyses of S leaves revealed three group of populations, namely from (1) Colchis, (2) eastern Caucasus (3) Talysh. Thus, our biometric analyses revealed similar pattern to the haplotypic differentiation of Z. carpinifolia detected using chloroplast markers described in the literature. We did not detected significant differences in the leaf characters between supposed Z. hyrcana and/or Z. carpinifolia subsp. yomraensis, when compared to Z. carpinifolia, thus not confirming their separate taxonomic status.

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. © 2012 The Author(s)., The collection of the majority of the material used in the present study was made possible through bilateral cooperation between the Polish Academy of Sciences and the Consejo Superior de Investigaciones Científicas (Spain) and unofficial cooperation between the Institute of Dendrology and the Faculty of Forestry of Kahramanmaraş Sutcu Imam University in Turkey. The study was partly sponsored by the Institute of Dendrology of the Polish Academy of Sciences.

We tested the performance of molecular markers and biometric traits in the identification of hybrids between closely related mountain pine (Pinus uncinata) and Scots pine (Pinus sylvestris). A plastid DNA marker and a set of morphological and anatomical needle traits were applied in analyses of individuals from several sympatric stands of the species and a single-species' population from southern Europe, used as a reference. A polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) marker from the plastid trnL–trnF region and morphological and anatomical traits clearly discriminated between the pure species. Significant differences were found between P. uncinata and P. sylvestris, mostly in the shape of epidermal cells and the number of stomata. Four putative hybrids with P. sylvestris morphology, but with P. uncinata plastid DNA haplotypes, were found in a population from Sierra de Gudar near Valdelinares, the southernmost locality of the latter species in eastern Spain. Discrimination analyses between and within populations placed these individuals on the edge of an agglomeration of P. sylvestris individuals. The results suggest that hybridization between the species is rare, but can result in cryptic hybrids morphologically similar to the maternal species. © 2010 The Linnean Society of London, Botanical Journal of the Linnean Society, 2010, 163, 473–485.

Differences in morphological and anatomical characters of needles between seedlings, saplings and adult trees of the endangered Pinus uliginosa from the Wegliniec Nature Reserve in SW Poland were examined biometrically and statistically assessed using the Student's t -test, Tukey–Kramer test, step-wise discrimination and agglomeration on Euclidean distances according to Ward's method. Pinus sylvestris adults and seedlings were used as comparative material. The results show that needles of all three P. uliginosa generations differ significantly from each other. In seedling needles, several anatomical characters were similar to those of P. sylvestris growing in the vicinity of the reserve. However, P. uliginosa had a lower number of resin canals, lower frequency of fibre-like sclerenchyma cells and higher frequency of thin-walled sclerenchyma cells with large lumens in the spaces between vascular bundles. Needle characters of saplings and adult trees of both species were distinctly more different than it was the case in the seedling stage.

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.

21 p., tablas, gráf., mapas, Juniperus drupacea is an eastern Mediterranean mountain tree with a disjunct geographical range. We hypothesized that this disjunct occurrence (the Peloponnese in Europe and the Taurus and Lebanon Mountains in Asia) should be reflected in the patterns of genetic and morphological diversity and differentiation. Nuclear microsatellite markers (nSSR) and biometric variables of the cones and seeds were examined on material sampled from four populations in Europe and eight in Asia. The Asian populations were characterized by a higher level of genetic diversity than the European populations. The genetic differentiation among populations was moderate but significant (FST = 0.101, P < 0.001). According to the clustering performed with BAPS, six genetically and geographically groups of populations were found: I and II from the Peloponnese; III from the Taurus Mountains; IV and V from the Anti-Taurus Mountains; and VI from the Lebanon Mountains. The level of genetic differentiation among these six groups (4.30%, P = 0.012) probably reflects long-lasting genetic isolation during the Pleistocene, as limited genetic admixture was found. In accordance with genetic analysis, the biometric investigations indicated a high level of morphological divergence between the European and Asian populations of the species, with further differentiation between the populations from the Taurus and Lebanon Mountains., The research was financially supported partly by the Polish Ministry of Science (under grant no. NN303 153037) and partly by the Institute of Dendrology (Poland) (under statutory activity).

Juniperus excelsa and J. thurifera are considered to originate from the same ancestor. As a result of occurring in geographically isolated refuges –J. excelsa in SE Europe and SW Asia and J. thurifera in SW Europe and NW Africa – their divergence could have taken place at the end of the Tertiary, with the climate cooling. Juniperus foetidissima occurs in SE Europe and SW Asia in territories shared with J. excelsa and is similar to and sometimes misidentified with it. The occurrence of the latter two species over the same area suggests they should be more similar to each other than to the geographically distant J. thurifera. Four populations of J. excelsa ssp. excelsa, four of J. thurifera and two of Juniperus foetidissima were examined on the basis of features of 10 cones and 10 shoots of 18–36 specimens each. Results of discrimination analysis, Mahalanobis distances and cluster analysis showed great similarity to J. excelsa and J. thurifera, while J. foetidissima was more distant. The results support the hypothesis of a common ancestor of J. excelsa and J. thurifera, but suggest another origin of J. foetidissima. © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society, 2007, 155, 483–495.

We studied the physicochemical properties of stemwood in saplings of silver birch ( Roth) and hybrid aspen ( L. × Michx.), grown for four years under artificially elevated relative air humidity (on average by 7%) in field conditions, using the Free Air Humidity Manipulation (FAHM) research facility in Estonia. Altogether 91 sample trees from three experimental plots with manipulated air humidity and from three control plots were cut in the dormant season and sampled for the analysis of cellulose, hemicellulose, acid detergent lignin, macronutrients (N, P, K), ash content, density, and calorific value of wood. The analysed trees grew significantly more slowly under elevated humidity conditions, with a more pronounced effect on aspens. Significantly higher concentrations of N and P were observed in the stemwood of both aspens and birches grown under elevated humidity. This could be the result of a change in the content of living parenchyma cells and/or enhanced retranslocation of nutrients into wood parenchyma. Additionally, humidification resulted in a significantly higher concentration of cellulose and a lower concentration of hemicellulose in aspen stemwood, and in significantly lower concentrations of cellulose and K in birch stemwood. Elevated humidity did not affect lignin concentration, ash content, basic density and calorific value of stemwood. Results from the FAHM experiment suggest that the increasing air humidity accompanying global warming at northern latitudes will affect the growth and functioning of deciduous trees and forests, with obvious consequences also for forest management and industry.Betula pendulaPopulus tremulaP. tremuloides

16 p., mapas, tablas, gráf., The phenotypic differentiation of relic P. sylvestris in southern Europe and southwestern Asia was verified using thirty-two populations sampled from the Iberian Peninsula, Massif Central, Balkan Peninsula, Crimea and Anatolia. Twenty-one morphological and anatomical needle traits and 18 cone morphological characteristics were examined to describe the population diversity and differentiation. The needle characters were not correlated to those of cone. The differences between regions were significant based on 12 needle and 9 cone characteristics, suggesting spatial isolation. The differentiation between the Iberian and Anatolian populations was the highest, which indicates the isolation by distance. The high level of morphological differentiation was also found among Iberian populations, supporting the already known complex history of the species in that region. Populations within other regions were differentiated at lower levels; however, the West Anatolian populations differed morphologically from the eastern ones. The described pattern of morphological differentiation supports the idea of the long-lasting existence of P. sylvestris in the south-European and Anatolian mountain regions. To conserve this variation, seed transfer between regions in the forest economy should be restricted., The research was financially supported by The Polish Ministry of Science (Contr. No. NN303 360535) and partly by Institute of Dendrology.

13 p., Mediterranean junipers are of special ecological importance as key components of resource islands in semi-arid mountain ecosystems of the Mediterranean basin. The fragmentation of their habitat, which was primarily natural and driven by climatic drought conditions, is currently being aggravated by anthropogenic pressure. In the framework of this concern, the present work aims to contribute establishing a genomic profile of Juniperus in its western Mediterranean range, with a special emphasis placed on J. thurifera. DNA contents were assessed by flow cytometry in 43 populations of nine taxa within their Mediterranean range (first reports for J. navicularis, J. thurifera subsp. africana and J. thurifera subsp. thurifera). Chromosome numbers were determined by orcein staining in eight taxa (first counts for J. oxycedrus subsp. badia, J. phoenicea subsp. phoenicea, J. phoenicea subsp. turbinata, of 2n = 2x = 22, and for J. thurifera subsp. thurifera, of 2n = 4x = 44). Tetraploid cytotypes have been the only ones found in the 19 populations of J. thurifera studied, this being the first report of a Juniperus species exclusively polyploid. In J. thurifera, C-value does not respond to habitat fragmentation, in the same way that genetic diversity within populations was previously shown to be unaltered, suggesting that this factor has not had, at least to date, a significant impact on populations at genomic and genetic levels. Habitat fragmentation leads to deeply age-biased populations with a male-biased imbalanced sex ratio (lack of females), indicating an urgent need to improve regeneration within the populations of this species., This work was subsidized by the Dirección General de Enseñanza Superior, Spain (project PB 97/1134), Ministerio de Ciencia e Innovación, Spain (projects CGL2010-22234-C02-01 and 02 / BOS) and the Generalitat de Catalunya, Catalonia (Ajuts a grups de recerca consolidats 2005/SGR/00344 and 2009/SGR/00439). AR was funded by "Proyectos Intramurales de Incorporación del Consejo Superior de Investigaciones Científicas: project 2009930I161". OH received a Juan de la Cierva postdoctoral grant from the Ministerio de Ciencia e Innovación

41 p., Background and aims: Juniperus excelsa M.-Bieb. is a major forest element in the mountains of the eastern part of Mediterranean and sub-Mediterranean regions. This study comprises the first morphological investigation covering a large part of the geographical range of J. excelsa and aims to verify the congruency between the morphological results and molecular results of a previous study. Methodology: We studied 14 populations sampled from Greece, Cyprus, Ukraine, Turkey and Lebanon, from which 11 have previously been investigated using molecular markers. Three hundred and ninety four individuals of J. excelsa were examined using nine biometric features characterising cones, seeds and shoots; and eight derived ratios. Statistical analyses were conducted in order to evaluate the intra and interpopulation morphological variability. Principal results: The level of intra-population variability observed did not show any geographic trends. The total variation mostly depended on the ratios of cone diameter/seed width and seed width/seed length. The discrimination analysis, the Ward agglomeration method and barrier analysis results showed a separation into three main clusters of the sampled populations. These results confirmed, in part, the geographic differentiation revealed by molecular markers with a lower level of differentiation and a less clear geographic pattern. The most differentiated populations using both markers corresponded to old, isolated populations in the high altitudes of Lebanon (>2000 m). Moreover a separation of the northern Turkish population from the southern Turkish populations was observed using both markers. Conclusions: Morphological variation together with genetic and biogeographic studies together make an effective good tool for detecting relict plant populations and also populations subjected to more intensive selection., The research was conducted within the statutory research programme of the Institute of Dendrology, Polish Academy of Sciences, Kórnik, Poland and supported by the Research Council of Saint-Joseph University of Beirut.

Context Taxus woodlands suffer from a lack of natural regeneration across its whole distribution range. Aims In Knyazhdvir Reserve in Ukraine Taxus baccata primarily competes with Abies alba. It has been assumed that in the conditions of deep shade, yews have a greater competitive advantage than firs. Methods To verify this hypothesis, a plot with both species growing under the canopy was established. Wood samples were taken from 20 trees of T. baccata and 20 trees of A. alba. Results There were no differences in the mean tree-ring width, height and age between both species. Due to a lack of spatial separation of both species, yews and firs inhabited the same area in the analysed plot. Fir seedlings (up to 0.5 m) were recorded to grow under yew saplings (above 0.5 m), but the inverse situation of yew seedlings growing under fir saplings was not seen. Conclusion Seedling distribution, tree-ring growth rate, possibility of growth of fir seedlings under yew saplings and greater potential growth suggested that fir was predisposed to having the competitive edge over yew. Our results may confirm the hypothesis that T. baccata has a restricted distribution because of weak competitive abilities and can exist only in habitats where faster growing species are absent. The results call into question the prevailing opinion that human influences are the principal cause for the decline of T. baccata.

Received 28 August 2015. Accepted 28 August 2015. A. Niglas, M. Alber, K. Suur, P. Kupper, and A. Sellin. Institute of Ecology and Earth Sciences, University of Tartu, Lai 40, 51005 Tartu, Estonia. A.K. Jasinska. Institute of Ecology and Earth Sciences, University of Tartu, Lai 40, 51005 Tartu, Estonia; Institute of Dendrology, Polish Academy of Sciences, Parkowa 5, 62-035 Kornik, Poland. Corresponding author: Aigar Niglas (e-mail: aigar.niglas@ut.ee). Fig. 3. Stomatal conductance (gS) versus leaf-to-air vapour pressure difference (VPDL) in leaves showing increasing response (IR) of stomatal conductance with rising VPDL. The IR data were divided into seven groups by VPDL; the data points represent means of the groups. 709

12 p., mapas, tablas, gráf., Juniperus thurifera is an important component of woodland communities of dry sites within the West Mediterranean region and is characterised by a strongly disjunctive geographic range. Two subspecies were recognised, subsp. thurifera in Europe and subsp. africana in Africa. The aim of the study was the comparison of phenetic diversity to the pattern of AFLP geographic differentiation of the species described in the literature. The examination of phenetic diversity was based on the biometrical analysis of 17 populations using 12 morphological characters of cone and seed. The differences among populations were analysed using Student’s t test, analysis of discrimination, UPGMA agglomeration and hierarchical analysis of variance. The majority of morphological characters differentiated at a statistically significant level between populations and between J. thurifera subsp. thurifera and subsp. africana. Three groups of populations were detected using multivariate statistical analyses. The first, well separated, is subsp. africana, while the following two concern subsp. thurifera. The morphological differentiation of populations appeared similar to that described on the AFLP. The Gibraltar Straight appeared to be the most important barrier., Funding the work was partly sponsored by the Institute of Dendrology of the Polish Academy of Sciences. The collection of material was made possible due to the bilateral cooperation of the Polish Academy of Sciences with the Spanish National Research Council "Consejo Superior de Investigaciones Científicas".

The taxonomic position of the population of tree-like, mostly polycormic individuals of pines from the Mshana peat bog in the Gorgany Mountains (East Carpathians, Ukraine) has been studied on the basis of the morphological characteristics of cones and needles, and anatomical characteristics of the needles. These features have been compared with the surrounding Pinus mugo population as well as P. uliginosa, P. mugo, P. sylvestris and P. uncinata from natural populations of the taxa. Tree-like individuals were found to have the most similar needles to P. uliginosa, but most similar cone characteristics to P. mugo. It was concluded, that the tree-like population has a relic character and can present the trace of the early migration of P. uliginosa from the West and its hybridisation with P. mugo.

The characters of Quercus robur and Q. petraea leaves are of main taxonomic value and the adult trees of both species can be distinguished on them. However, young individuals, mostly seedlings but also saplings, are told to be undistinguishable or only partly distinguishable on the leaf morphology. The aim of the study was to verify this hypothesis on the basis of biometrical analyses of leaf characteristics of adults trees and saplings in two mixed oak woods, one located close to the north-eastern limit, the other about 400 km inside of the Q. petraea range in Poland. The analysis of discriminations and minimum spanning tree on the squares of Mahalanobis distances were analysed to find differences between Q. robur, Q. petraea and intermediate adults and saplings. The differences between saplings of Q. robur and Q. petraea were found lower than between adult trees. Nevertheless, the biometrical analysis confirmed determination of saplings in the field.