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Salix ×browiczii (Salicaceae) – a new nothospecies from northeastern Greece
A hybrid between Salix triandra and S. xanthicola, occurring in the Rhodope Mountains in northeastern Greece, is described as a new nothospecies. It differs from S. triandra by having distinctly hairy young stems and more deeply serrate-dentate leaf margins, and from S. xanthicola by a smooth, unstructured (without conicoids) wax layer on the lower side of the leaves and the presence of subsessile glands on the petioles.
The evolutionary heritage and ecological uniqueness of Scots pine in the Caucasus ecoregion is at risk of climate changes
AbstractScots pine is one of the most widely occurring pines, but future projections suggest a large reduction in its range, mostly at the southern European limits. A significant part of its range is located in the Caucasus, a global hot-spot of diversity. Pine forests are an important reservoir of biodiversity and endemism in this region. We explored demographic and biogeographical processes that shaped the genetic diversity of Scots pine in the Caucasus ecoregion and its probable future distribution under different climate scenarios. We found that the high genetic variability of the Caucasian populations mirrors a complex glacial and postglacial history that had a unique evolutionary trajectory compared to the main range in Europe. Scots pine currently grows under a broad spectrum of climatic conditions in the Caucasus, which implies high adaptive potential in the past. However, the current genetic resources of Scots pine are under high pressure from climate change. From our predictions, over 90% of the current distribution of Scots pine may be lost in this century. By threatening the stability of the forest ecosystems, this would dramatically affect the biodiversity of the Caucasus hot-spot.
Niche expansion of polyploid cytotypes shaped the phylogeographical history of the i Salix retusa complex in the European Alpine System
Abstract Background and Aims Alpine plants exhibit diverse postglacial recolonization patterns following the last glacial periods. Polyploidization may have impacted these dynamics by introducing ecological and physiological novelties that facilitate adaptation to changing environments. However, consistent trends in the recolonization, niche optima and dynamics of polyploids and their related diploids remain elusive. In this study, we investigate the biogeographical history of the Salix retusa polyploid complex in the European Alpine System. By comparing genetic patterns and their climatic and edaphic niche optima, we explore how polyploidization shaped species’ geographical distributions by influencing their ecological adaptation. Methods RAD sequencing was used to reconstruct the biogeographical history and genetic structure of two related willow species. High-resolution edaphic and climatic data were used to compare the niche optima, breadth and dynamics between the species. Key Results The distribution of the polyploid species overlaps with more peripheral refugial areas, which correlates with its broader geographical range in the European Alpine System. However, genetic analyses suggest more potential peripheral glacial refugia within the Alps for the diploid. Our findings indicate niche conservatism within the S. retusa complex, with the polyploid species having a broader niche but the diploid being adapted to a more extreme niche. Conclusions In our study species, polyploidy is associated with a higher genetic diversity and geographical structure, which might be due to a broader ecological niche and distribution. However, it did not appear to facilitate adaptation or confer a survival advantage during the last glaciation.
Revisiting the taxonomy of Populus lasiocarpa × P. wilsonii hybrids
Although hybrids between Populus lasiocarpa and P. wilsonii have been known for many years, they have not been given a valid nothospecies name. Resolving the classification issue of these bigleaf poplars is now even more necessary because they are known not only from cultivation, but recent evidence confirms their spontaneous occurrence in Hubei Province, China (Zhang, unpublished information). The two species were first artificially crossed in 1956 in Poland and again independently in 1974 in Sweden. Initially, this taxon was described as P. ×wilsocarpa (Bartkowiak & Bugała, 1978). However, this name was invalid due to the lack of Latin diagnosis (which was required at that time) and lack of type designation. In 1996, Böcker and Koltzenburg proposed the name P. ×kornicensis for this hybrid, but it too was invalid for similar reasons and lack of description. In our work, we revisited these poplars and validated the name proposed by Böcker and Koltzenburg by providing a description and type designation. Considering the overall appearance of these hybrid poplars (silhouette, branching pattern), they bear a closer resemblance to P. wilsonii. Other analyzed morphological features are mostly intermediate compared to the parent species, but overall, they lean slightly more towards P. lasiocarpa. We highlight the main diagnostic characteristics that distinguish these species.
Morphological differences in populations of Jacobaea erucifolia: Genetic differentiation, phenotypic plasticity or ecotypes?
Accurate taxonomic classification is essential for effective conservation strategies, especially for rare and endangered species. Traditionally based on morphology, such classifications may be challenged by recent advances in molecular tools that reveal hidden genetic structure or lack thereof. Jacobaea erucifolia is a declining species in Poland, primarily threatened by habitat loss, fragmentation, and competition with invasive species. Although two subspecies—erucifolia and tenuifolia—have been identified in Poland based on leaf morphology and ecological preferences, the taxonomic status of these forms remains unclear. This study aimed to evaluate the genetic variation within ten Polish populations of J. erucifolia and assess whether the observed morphological differences correspond to genetic divergence. Based on morphology, four populations were classified as subsp. erucifolia and six as subsp. tenuifolia. Reference populations of confirmed subspecies tenuifolia were included from Slovakia, Hungary, and the Netherlands. Genetic analyses were conducted using amplified fragment length polymorphisms (AFLPs), chloroplast DNA restriction fragments (RFLP), cpDNA, and nuclear internal transcribed spacer (ITS) ribosomal DNA sequences. The results revealed a high level of admixture and no significant genetic differentiation among Polish populations, regardless of their initial morphological classification. All Polish populations formed a single genetic group, distinct from foreign tenuifolia samples, although no diagnostic genetic markers were identified to separate these two groups (subspecies) of J. erucifolia definitively. Moreover, sequence data showed no differences among all analyzed individuals, further challenging the validity of subspecies differentiation. These findings suggest that the morphological variation observed within Polish populations likely reflects phenotypic plasticity rather than subspecies-level divergence. Consequently, subspecies tenuifolia does not appear to occur in Poland, and observed differences between Polish populations and those from neighboring countries may represent ecotypic variation. Our study underscores the necessity of integrating genetic and morphological data when resolving taxonomic ambiguities, especially in the context of conservation planning. Future research involving broader geographic sampling and deeper analysis of hybridization patterns will help clarify the evolutionary history and and population dynamics of J. erucifolia.
No wonder, it is a hybrid. Natural hybridization between Jacobaea vulgaris and J. erucifolia revealed by molecular marker systems and its potential ecological impact
AbstractProgressive changes in the environment are related to modifications of the habitat. Introducing exotic species, and interbreeding between species can lead to processes that in the case of rare species or small populations threatens their integrity. Given the declining trends of many populations due to increased hybridization, early recognition of hybrids becomes important in conservation management. Natural hybridization is prevalent in Jacobaea. There are many naturally occurring interspecific hybrids in this genus, including those between Jacobaea vulgaris and its relatives. Although Jacobaea erucifolia and J. vulgaris often co‐occur and are considered closely related, apart from the few reports of German botanists on the existence of such hybrids, there is no information on research confirming hybridization between them. Morphologically intermediate individuals, found in the sympatric distributions of J. vulgaris and J. erucifolia, were hypothesized to be their hybrids. Two molecular marker systems (nuclear and chloroplast DNA markers) were employed to test this hypothesis and characterize putative hybrids. Nuclear and chloroplast DNA sequencing results and taxon‐specific amplified fragment length polymorphism (AFLP) fragment distribution analysis confirmed the hybrid nature of all 25 putative hybrids. The AFLP patterns of most hybrids demonstrated a closer relationship to J. erucifolia, suggesting frequent backcrossing. Moreover, they showed that several individuals previously described as pure were probably also of hybrid origin, backcrosses to J. erucifolia and J. vulgaris. This study provides the first molecular confirmation that natural hybrids between J. vulgaris and J. erucifolia occur in Poland. Hybridization appeared to be bidirectional but asymmetrical with J. vulgaris as the usual maternal parent.