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Disentangling relationships within the disjunctly distributed Alyssum ovirense/A. wulfenianum group (Brassicaceae), including description of a novel species from the north-eastern Alps
Abstract
Alyssum ovirense (Brassicaceae) is disjunctly distributed in the eastern Alps, predominantly occurring in the southern limestone Alps, but with one isolated population on the Hochschwab massif in the northern limestone Alps. The closely related rare and narrow endemic A. wulfenianum is restricted to gravel beds in a few rivers in the southern Alps draining the distribution area of A. ovirense. Applying molecular (amplified fragment length polymorphism fingerprinting and sequencing of plastid and nuclear DNA), karyological (flow cytometry and chromosome counts) and morphometric methods to a set of populations sampled throughout the distribution range, we evaluated the status of the population on the Hochschwab massif and the relationship between high-elevation A. ovirense and low-elevation A. wulfenianum. The population on Hochschwab massif is hexaploid, morphologically clearly divergent and grows in vegetation patches and dense alpine grasslands, whereas southern Alpine A. ovirense inhabits sparsely vegetated limestone screes. Molecular data show that the former represents a genetically isolated lineage which is formally described as A. neglectum sp. nov. All populations from the southern limestone Alps, including A. wulfenianum, are diploid. Although A. wulfenianum is genetically nested in A. ovirense, its morphological and ecological differentiation justifies recognition at the subspecific level. As A. wulfenianum has priority over A. ovirense, the correct names are A. wulfenianum subsp. wulfenianum and A. wulfenianum subsp. ovirense. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 176, 486–505.
... Alyssum montanum-A. repens is a phylogenetically young species complex that comprises diploids, tetraploids and hexaploids growing in open habitats from lowlands (coastal sand dunes, dry grasslands, rocky sites) to the alpine belt (alpine screes and grasslands), mainly on calcareous or serpentine bedrock (Magauer et al., 2014;Španiel et al., 2011, 2017aZozomová-Lihová et al., 2014). Its origin and initial diversification have been dated to the early Pleistocene, with most speciation events occurring in the last 1 to 2 million years and likely influenced by glaciation periods (Cetlová et al., 2021). ...
... The extent of interspecific gene flow is unknown, but hybrids have rarely been detected (Španiel et al., 2012a), likely due to allopatric distribution patterns and ecological specialization rather than strong reproductive barriers between species. Previous studies based mainly on AFLP markers, morphometric and flow-cytometric analyses resulted in a substantial taxonomic revision of the complex with reassessed species circumscriptions and descriptions of new species and subspecies (Magauer et al., 2014;Španiel et al., 2012bZozomová-Lihová et al., 2014). Traditional genetic markers, which included AFLP markers and DNA sequences of selected nuclear and chloroplast regions, provided initial evolutionary insights, but could hardly resolve phylogenetic relationships between species (Melichárková et al., 2017(Melichárková et al., , 2019Španiel et al., 2017aZozomová-Lihová et al., 2014). ...
... Its speciation events could be dated back to the Pleistocene (Cetlová et al., 2021) and were likely affected by range dynamics in response to past glaciation cycles, generally accompanied by geographic isolations, ecological diversification, and secondary contacts with hybridization events (Marques et al., 2018;Nieto Feliner, 2011, 2014. Indeed, previous studies focusing on selected Alyssum species have suggested that these processes may have significantly shaped their evolution (Magauer et al., 2014;Melichárková et al., 2019;Zozomová-Lihová et al., 2020). Phylogenetic reconstructions in this species complex must therefore take into consideration both divergent (bifurcating) and reticulate patterns (Linder & Rieseberg, 2004;Oxelman et al., 2017;Yan et al., 2022), and face challenges with weakly differentiated diploids and multiple related sibling polyploids (see e.g., Brandrud et al., 2020;Kamneva et al., 2017). ...
Elucidating the evolution of recently diverged and polyploid-rich plant lineages may be challenging even with high-throughput sequencing, both for biological reasons and bioinformatic difficulties. Here, we apply target enrichment with genome skimming (Hyb-Seq) to unravel the evolutionary history of the Alyssum montanum-A. repens species complex. Reconstruction of phylogenetic relationships in diploids supported recent and rapid diversification accompanied by reticulation events. Of the four main clades identified among the diploids, three clades included species from the Alps, Apennine and Balkan peninsulas, indicating close biogeographic links between these regions. We further focused on the clade distributed from the Western Alps to the Iberian Peninsula, which comprises numerous polyploids as opposed to a few diploids. Using a recently developed PhyloSD (phylogenomic subgenome detection) pipeline, we successfully tracked the ancestry of all polyploids. We inferred multiple polyploidization events that involved two closely related diploid progenitors, resulting into several sibling polyploids: two autopolyploids and six allopolyploids. The skewed proportions of major homeolog-types and the occurrence of some minor homeolog-types, both exhibiting geographic patterns, suggest introgression with the progenitors and other related diploids. Our study highlights a unique case of parallel polyploid speciation that was enhanced by ecological and geographic separation and provides an excellent resource for future studies of polyploid evolution.
... Magauer, Schönswetter & Frajman]. Disjunct populations from the Hochschwab massif (northern limestone Alps) growing in dense alpine grasslands, which are hexaploid and genetically and morphologically distinct from A. wulfenianum, were recently described as Alyssum neglectum Magauer, Frajman & Schönswetter (Magauer et al., 2014). In the south-western Alps, tetraploid-hexaploid populations previously attributed to Alyssum montanum L.s.s. ...
... Multivariate morphometric analyses compared with genetic, ploidy and distribution patterns have proved to be the most efficient approach to delineate species of this complex (e.g. Magauer et al., 2014;Zozomová-Lihová et al., 2014;Španiel et al., 2017b). In this study, we focus on the previously mentioned morphologically distinct populations of Alyssum from the Aosta Valley, including a disjunct population found north of the Simplon Pass (eastern Valais, Switzerland), and address the following questions. ...
... Despite weakly resolved phylogenetic relationships, species in the complex are mostly well defined genetically, geographically and ecologically. The species complex includes numerous endemics that are geographically separated mainly in western Europe, the Alps and the Apennines (Španiel et al., 2011b;Magauer et al., 2014;Zozomová-Lihová et al., 2014), although more complicated patterns have been observed in the Balkans (Španiel et al., 2017a,b). Isolation by distance plays an important role and has promoted speciation in this species complex. ...
The European Alps show a high degree of endemism associated mainly with the location of glacial refugia and environmental heterogeneity. Several Alpine endemics have evolved in the genus Alyssum. Here we study perennial Alyssum populations in the Western Alps, mainly distributed in the Aosta Valley region, which hosts high species diversity, although endemics are rare. We addressed the recently described stenoendemic A. rossetii and taxonomically uncertain populations usually attributed to A. montanum s.s. to clarify their phylogenetic position and morphological differentiation. The latter entity has been shown to be distinct from A. montanum s.s. and is described as a new species, Alyssum cognense, phylogenetically placed in the A. montanum-A. repens species complex. Both morphological and genetic patterns revealed that its closest relative occurs in the central Balkans. We present detailed ecological characteristics and morphological differentiation of A. cognense sp. nov. from its relatives and geographically closest species and speculate on its biogeographic origin. Genetic patterns (reduced diversity and nestedness) suggest long-distance dispersal from the central Balkan Peninsula. The second studied species, A. rossetii, is phylogenetically distant and belongs to the mainly Asian Alyssum section Gamosepalum lineage, which includes few representatives in southern and eastern Europe. The phylogenetically closest species of A. rossetii are Anatolian endemics, so this extreme disjunction remains puzzling. The present study illustrates the need for in-depth taxonomic and phylogenetic studies, even in well-explored Alpine regions, and also shows that the processes underlying the evolution of endemics can be complex and poorly understood.
... The current list of Alyssum taxa and their distributional data in the Flora Croatica Database (Nikolić 2018) served as the starting point for the review. All relevant Croatian literature with the data of taxa occurrence and problematics as well as most recent molecular systematic studies (Španiel et al. 2011a,b, 2012a,b, 2015, 2017a,b, Rešetnik et al. 2013, Magauer et al. 2014, Zozomova-Lihová et al. 2014) were analysed. The nomenclature was updated according to AlyBase (http://www.alysseae.sav.sk; ...
... repens polyploid complex. The group has been extensively studied with genetic (plastid DNA sequences, low-copy nuclear genes and amplified fragment length polymorphism markers), flowcytometric and morphological data during the last seven years (Španiel et al. 2011a, b, 2012a, b, 2017a, b, Magauer et al. 2014, Arrigo et al. 2016, Melichárková et al. 2017, which resulted in changes in circumscriptions and nomenclature of taxa (Španiel et al. 2012a, 2015, 2017b). The complex is notorious due to the very complex morphological variation patterns and therefore the taxonomic treatment of the group is also based on genetic distinction and allopatric distributions of lineages. ...
... The two other taxa that should be excluded from the Croatian flora are A. ovirense and A. wierzbickii. The occurrence of A. ovirense in Croatia was already rejected by Trinajstić (1983) and Plazibat (2009) and according to new molecular and morphologically based studies A. ovirense should be treated as a subspecies of Alpine species A. wulfenianum which is not present on the Balkan Peninsula (Magauer et al. 2014. The second species without any reliable data indicating its presence in Croatia is A. wierzbickii (Plazibat 2009). ...
Until now, the genus Alyssum L. has been represented by a total of 19 taxa in the Flora Croatica Database (FCD). In this paper a detailed review of this genus in Croatian flora was carried out based on most recent phylogenetic, taxonomic, and nomenclatural studies. Based on the presented results five of the current taxa are not subjected to any nomenclatural change, five require nomenclatural change, nine should be excluded from the Croatian flora while one new taxon should be included. Three taxa should be excluded from the genus Alyssum and included in the resurrected genus Odontarrhena C.A.Mey. ex Ledeb., namely O. muralis, O. tortuosa and O. metajnae. The most substantial change in the genus Alyssum is the exclusion of A. montanum and some related segregates (variety molliusculum and subspecies pagense) from Croatian flora and classification of the attributed populations as A. austrodalmaticum, A. gmelinii, A. pluscanescens and A. repens. The other excluded taxa, without reliable data indicating their presence in Croatia, are: A. hirsutum, A. ovirense, A. repens subsp. transsilvanicum, A. repens subsp. trichostachyum and A. wierzbickii. Following this review, taking into account the latest taxonomic and nomenclatural revisions, the genus Alyssum is represented by eight species and the genus Odontarrhena by three species in Croatian flora.
https://hrcak.srce.hr/207526
... (Jalas et al. 1996). The affinity of A. bosniacum to the latter species was rejected in recent studies (Zozomová-Lihová et al. 2014;Magauer et al. 2014). It is also genetically related neither to A. montanum nor to A. scardicum (Španiel et al. 2017). ...
... subsp. wulfenianum (Magauer et al. 2014). Two subspecies have mostly been recognized: subsp. ...
... Alyssum spruneri subgroup 'dinaricum' includes tetraploid and hexaploid populations from Serbia and Montenegro. Populations in these regions used to be assigned to A. scardicum, A. ovirense or A. montanum (Jalas et al. 1996), but neither has been confirmed by molecular studies (Zozomová-Lihová et al. 2014;Magauer et al. 2014;Španiel et al. 2017). The plants of this group are characterized by relatively large flowers and a sparse indumentum on leaves, resembling A. bosniacum or some populations of A. repens. ...
A multivariate morphometric study of the Balkan taxa from the diploid–polyploid complex of Alyssum montanum-A. repens (Brassicaceae) was performed. The western European species A. montanum and central European A. gmelinii were also included in the study for comparison. A total of 1969 individuals from 89 populations were studied to explore morphological differences among taxa or genetic groups revealed in a parallel study by a combination of molecular and cytometric evidence. According to our results, several Balkan taxa are clearly morphologically differentiated, namely A. handelii, A. moellendorfianum, A. pirinicum, A. rostratum and A. wierzbickii. Other species—A. bosniacum, A. montenegrinum, A. reiseri and A. vernale—exhibit overlaps in values of the most differentiating characters, but can all be steadily distinguished. Alyssum
repens, which is not genetically compact, is still morphologically recognizable from other Balkan taxa. Two species, A. austrodalmaticum and A. gmelinii, despite having clear genetic differences and an allopatric distribution, only have minor morphological differences. The tentatively accepted genetically heterogeneous species A. spruneri, which includes a major portion of the Greek and central Balkan populations, is also extraordinarily variable in morphology. An identification key of the studied taxa and their synonymy are provided. The taxonomic treatments of the recognized species and their geographic distribution are discussed.
... Relatively recent (Pleistocene) long-distance dispersal from the Balkan Peninsula was suggested for the western Alpine endemic Alyssum cognense (Španiel et al., 2022). A biogeographic relationship between the Balkans and the Alps was also documented by eastern Alpine Alyssum neglectum and central Dinaric A. bosniacum (Magauer et al. 2014;Zozomová-Lihová et al. 2014;Španiel et al. 2017a, b) or eastern Alpine Androsace hausmanni and Montenegrian A. komovensis (Schönswetter and Schneeweiss 2009). However, the biogeographic pattern in Androsace seems to be the result of an ancestral range expansion from the center of diversity in the European Alps into the Balkan Peninsula rather than the consequence of colonization in the opposite direction (Schönswetter and Schneeweiss 2009). ...
... The reason could be the younger age of the Apennine Peninsula whose largest part was either an island or a peninsula of the Alps for a long period in the Tertiary (Meulenkamp et al. 2003;Frajman and Schönswetter 2017). Moreover, the Balkan Peninsula is larger and better connected to the rest of the continent and is thus expected to have higher species richness according to the classical island biogeography theory (MacArthur and Wilson 1967). Notably, the majority of available studies are based on species that have larger distributions in the Balkan Peninsula than in the Apennine Peninsula. ...
The Balkan Peninsula is widely acknowledged as one of the centers of European biodiversity and a major glacial refugium for plant species. Its extensive geographic heterogeneity and diverse mosaic of habitats, coupled with relatively high environmental stability over long periods, have enabled the diversification of lineages and simultaneously fostered the long-term survival of diverse species. The increasing number of phylogeographically studied plant species in the region has substantially contributed to a better understanding of the relationships among closely related taxa and provides significant insights into intraspecific lineage differentiation. The present paper reviews the current knowledge on plant phylogeography in the Balkan Peninsula. By providing an updated overview of the most recent studies dealing with the diversity and evolution of Balkan plants, we explore the phylogeographic patterns and roles of refugia in structuring genetic diversity and highlight the crucial evolutionary processes that shaped the diversity of plants in the region. Molecular clock-based estimations highlight the importance of Pleistocene climatic fluctuations across taxonomic groups and lineage distribution patterns corroborate the persistence of multiple glacial refugia. Spatial congruence in phylogeographic splits is determined and discussed. An examination of phylogeographic connections with adjacent regions (i.e., the Alps, Apennine Peninsula, Asia Minor, Carpathians, and central Europe) uncovers several consistent patterns. Additionally, allopatric and ecological speciation, polyploidy, and hybridization are identified as crucial evolutionary mechanisms acting in the Balkan Peninsula and shaping species diversity. Furthermore, the existing research gaps are identified and future approaches with the potential to better understand the unique Balkan flora are highlighted.
... Most species show fairly restricted, allopatric distribution ranges, several are local endemics whereas only a few are more widespread, and even those show geographically structured genetic variation (Zozomová-Lihová et al., 2014b;Španiel et al., 2017b, 2019. In fact, several mountain ranges in Europe (the Pyrenees, Alps, Apennines, Carpathians, and Dinarides) harbor at least one endemic taxon from this species complex , 2017b, 2019Magauer et al., 2014;Zozomová-Lihová et al., 2014b). It has been suggested that restricted seed dispersal along with recent diversification (late Pliocene/early Pleistocene) and possibly also ecological differentiation are responsible for the present, geographically structured patterns in this species complex (Zozomová- Lihová et al., 2014b). ...
... They comprised both the diploid and tetraploid cytotype (see Results). Furthermore, we analyzed the species' closest relatives from Central Europe and the Balkan Peninsula, as well as geographically adjacent taxa (Magauer et al., 2014;Španiel et al., 2017a) Španiel et al., 2017a, b), were included only in the ITS and DET1 datasets. Although these species did not turn out to be the closest relatives of A. repens based on AFLP patterns (see Španiel et al., 2017a), screening of DET1 variation within a broader spectrum of Balkan species (J. ...
Premise:
Disjunct distributions have been commonly observed in mountain plant species and have stimulated phylogeographic and phylogenetic research. Here we studied Alyssum repens, a member of the polyploid species complex A. montanum-A. repens, which exhibits SE Alpine-Carpathian disjunctions with a large elevational span and consists of diploid and tetraploid populations. We aimed to investigate the species' genetic and cytotype structure in the context of its distribution patterns, to elucidate the polyploid origins and to propose an appropriate taxonomic treatment.
Methods:
We combined AFLP fingerprinting markers, sequence variation of the highly repetitive ITS region of rDNA and the low-copy DET1 nuclear gene, genome size, and morphometric data.
Results:
We identified four geographically structured genetic lineages. One consisted of diploid populations from the foothills of the Southeastern Alps and neighboring regions, and the three others were allopatric montane to alpine groups comprising diploids and tetraploids growing in the Southeastern Carpathians and the Apuseni Mts. in Romania.
Conclusions:
We inferred a vicariance scenario associated with Quaternary climatic oscillations, accompanied by one auto- and two allopolyploidization events most likely involving a northern Balkan relative. Whereas genetic differentiation and allopatric distribution would favor the taxonomic splitting of this species, the genetic lineages largely lack morphological distinguishability, and their ecological, cytotype and genome size divergence is only partial. Even though we probably face here a case of incipient speciation, we propose to maintain the current taxonomic treatment of Alyssum repens as a single, albeit variable, species.
... Specifically, many studies have used AFLP data and morphometrics to address taxonomic conflicts in groups of closely related plant taxa (e.g. [43][44][45][46][47] ). In the case of Cymbalaria, AFLP ( Fig. 2) and morphometric analyses (Fig. 6) allow for the recognition of four distinct entities within a previously identified monophyletic group of Cymbalaria species endemic to the Balearic Islands, Corsica and Sardinia 12 . ...
... For both plastid regions, the reaction mix (total volume 25 μL) contained 9 μL of RedTaq ReadyMix PCR Reaction Mix (Sigma-Aldrich), 1.05 μL bovine serum albumin (BSA; 1 mg mL −1 ; Promega), 1.05 μL of each primer (10 μM) and 1.5 μL template DNA. We followed the PCR profiles described in Galbany-Casals et al. 116 for the ndhF and Magauer et al. 45 for the rpl32-trnL (UAG) spacer. ...
Abstract The Balearic Islands, Corsica and Sardinia (BCS) constitute biodiversity hotspots in the western Mediterranean Basin. Oligocene connections and long distance dispersal events have been suggested to cause presence of BCS shared endemic species. One of them is Cymbalaria aequitriloba, which, together with three additional species, constitute a polyploid clade endemic to BCS. Combining amplified fragment length polymorphism (AFLP) fingerprinting, plastid DNA sequences and morphometrics, we inferred the phylogeography of the group and evaluated the species’ current taxonomic circumscriptions. Based on morphometric and AFLP data we propose a new circumscription for C. fragilis to additionally comprise a group of populations with intermediate morphological characters previously included in C. aequitriloba. Consequently, we suggest to change the IUCN category of C. fragilis from critically endangered (CR) to near threatened (NT). Both morphology and AFLP data support the current taxonomy of the single island endemics C. hepaticifolia and C. muelleri. The four species had a common origin in Corsica-Sardinia, and two long-distance dispersal events to the Balearic Islands were inferred. Finally, plastid DNA data suggest that interspecific gene flow took place where two species co-occur.
... Many recent taxonomic publications have exploited morphology under the umbrella of integrative taxonomy [23] which relies on the use of multiple data sources for inference [23]. The techniques most commonly combined with morphometrics are molecular [24], but can also include cytometry [23,25], chromosome counts [25] or the chemical composition of secreted compounds [26], all of which involve destructive sampling. The most important aspect of integrative taxonomy is the use of the appropriate data sources for the organisms in question. ...
... Many recent taxonomic publications have exploited morphology under the umbrella of integrative taxonomy [23] which relies on the use of multiple data sources for inference [23]. The techniques most commonly combined with morphometrics are molecular [24], but can also include cytometry [23,25], chromosome counts [25] or the chemical composition of secreted compounds [26], all of which involve destructive sampling. The most important aspect of integrative taxonomy is the use of the appropriate data sources for the organisms in question. ...
Morphological classification of living things has challenged science for several centuries and has led to a wide range of objective morphometric approaches in data gathering and analysis. In this paper we explore those methods using apple cultivars, a model biological system in which discrete groups are pre-defined but in which there is a high level of overall morphological similarity. The effectiveness of morphometric techniques in discovering the groups is evaluated using statistical learning tools. No one technique proved optimal in classification on every occasion, linear morphometric techniques slightly out-performing geometric (72.6% accuracy on test set versus 66.7%). The combined use of these techniques with post-hoc knowledge of their individual successes with particular cultivars achieves a notably higher classification accuracy (77.8%). From this we conclude that even with pre-determined discrete categories, a range of approaches is needed where those categories are intrinsically similar to each other, and we raise the question of whether in studies where potentially continuous natural variation is being categorised the level of match between categories is routinely set too high.
... Alyssum diffusum occurs only in the Apennine Peninsula (Španiel et al. 2012b), A. montanum in France, Germany and Switzerland and A. gmelinii in central and eastern Europe (Španiel et al. 2012a;Zozomová-Lihová et al. 2014). The presence of Alpine species A. wulfenianum (which includes A. ovirense as a subspecies) in the Balkans was already rejected in previous studies (Zozomová-Lihová et al. 2014;Magauer et al. 2014). ...
... Mountain diploid and tetraploid populations from Bosnia and Herzegovina form a genetic cluster that is treated as a separate species here, A. bosniacum. Two previously published tetraploid chromosome numbers of A. montanum (van Loon and Kieft 1980;Magauer et al. 2014) are attributable to this species (see Španiel et al. 2015), but the diploids are reported here for the first time. Alyssum bosniacum represents a sister genetic group to the adjacent lowland species A. moellendorfianum. ...
The Balkan Peninsula is an important diversity and speciation centre for many species groups. The high genetic, karyological and morphological complexity of the Alyssum montanum-A. repens species group (Brassicaceae) in the Balkans makes it a challenging study subject for exploring different speciation mechanisms and their taxonomic consequences. In the present study, ploidy level and genetic (AFLPs and chloroplast DNA sequences) data were examined and confronted with recent taxonomic concepts. Remarkable genetic and morphological variation, which is often geographically structured, and high incidence of polyploids suggest a very complex evolutionary history in this area, involving allopatric differentiation and past hybridisation and polyploidisation events. A new taxonomic treatment, differing substantially from recent concepts, is suggested. Several previously recognised taxa, including many endemics, such as A. austrodalmaticum, A. handelii, A. moellendorfianum, A. pirinicum and A. wierzbickii, are confirmed as distinct. Several other taxa are suggested to be resurrected or elevated to the species level, namely, A. bosniacum, A. montenegrinum, A. reiseri and A. vernale. Phylogenetic relationships among populations from the central Balkans and Greece are still partly blurred apparently due to more extensive reticulations, and their taxonomic classifications remain provisional. They are treated here under the tentative name A. spruneri. The patterns of variation revealed in the present study highlight the importance of the Balkan Peninsula for the persistence and diversification of vascular plants.
... Indeed, AFLPs, as a DNA fingerprinting method (Bussell, Waycott & Chappill, 2005;Meudt & Clarke, 2007), have proved efficient, especially when high resolution is needed such as for delimiting species, uncovering relationships of closely related species or describing intraspecific genetic structure (e.g. Martínez-Ortega et al., 2004;Kuzmanović et al., 2013;Magauer et al., 2014;Rešetnik, Frajman & Schönswetter, 2016). However, their utility for reconstructing polyploid and reticulate evolution may be limited (see e.g. ...
... They all are geographically distant and, as far as available genetic data indicate, also genetically divergent: the south-eastern Alpine endemic A. wulfenianum Willd. (diploid only, Magauer et al., 2014), the central to southern Apennine A. diffusum Ten. (diploid-polyploid, Španiel et al., 2011) and some Balkan endemics (several diploid and diploid-polyploid species of uncertain circumscriptions and relationships; S. Španiel et al., unpubl. ...
Reconstructing polyploid origins and reticulate evolution is challenging even if several independent markers are employed. The Alyssum montanum–A. repens group is a species complex comprising multiple polyploids with as yet insufficiently investigated origins. Here we search for the parentage of two related polyploids, A. montanum (s.s.) and A. rhodanense, using sequences of two low-copy nuclear genes and show how these data can complement and strengthen evidence based on plastid DNA and AFLPs. Whereas A. montanum, even in its strict circumscription, represents a complex of diploid and tetraploid lineages distributed from south-western Germany and western Switzerland to the foothills of the Pyrenees, A. rhodanense is a hexaploid stenoendemic from south-eastern France. In both polyploids, we revealed divergent gene copies (homoeologues) that point to their allopolyploid origins and allow the identification of their parental species. The results suggest that tetraploids of A. montanum originated from hybridization between diploids of this species and the Iberian A. fastigiatum and that multiple allopolyploidization events took place. For A. rhodanense, we propose an allopolyploid origin involving A. gmelinii and tetraploids of A. montanum. We illustrate how combined evidence from several markers contributes to more comprehensive and confident inferences about polyploid origins.
... In particular, DNA ploidy levels were estimated by fl ow cytometry and calibrated by chromosome counting of a few individuals of each ploidy level (for details, see Španiel et al., 2011a ). Most of the ploidy level records were published in previous studies ( Španiel et al., 2011a, b , 2012aZozomová-Lihová et al., 2014 ;Magauer et al., 2014 ), and the rest are presented here as new records (Appendix S1 in the online Supplemental Data of this article). With the exception of complex and so far insuffi ciently resolved species diversity and evolutionary history in the Balkans (S. ...
... Here, we assign populations to allo-or autopolyploids according to the available evidence of divergence among their parental genomes (following Stebbins, 1985 ), irrespectively of taxonomic treatment (Appendix S1 summarizes every population assignment in line with available evidence). Accordingly, the consistent presence of multiple differentiated copies of nuclear genes within a specimen (assessed via cloning and sequencing of the internal transcribed spacer using primers and PCR conditions of Magauer et al. [2014] , Overview of the 205 populations included in our survey, based on a georeferenced database addressing the taxonomy and molecular genetics of 96 diploid, 49 hybrid allopolyploid, and 60 autopolyploid populations belonging to the Alyssum montanum s.l. species complex (from Španiel et al., 2011a, b , 2012aZozomová-Lihová et al., 2014 ; and references therein; see further details in online Appendix S1). ...
Premise of the study:
After decades of interest, the contribution of hybridization to ecological diversification remains unclear. Hybridization is a potent source of novelty, but nascent hybrid lineages must overcome reproductive and ecological competition from their parental species. Here, we assess whether hybrid speciation is advantageous over alternative modes of speciation, by comparing the geographical and ecological ranges and climatic niche evolutionary rates of stabilized allopolyploid vs. autopolyploids in the Alyssum montanum species complex.
Methods:
We combined an extensive review of studies addressing the systematics and genetic diversity of A. montanum s.l., with flow cytometry and cloning of nuclear markers, to establish the ploidy level and putative hybrid nature of 205 populations. The respective geographic distribution and climatic niche evolution dynamics of the allo- and autopolyploids were investigated using multivariate analyses and comparative phylogenetic approaches.
Key results:
As expected by theory, allopolyploids occur mainly along contact zones and are generally spatially overlapping with their diploid counterparts. However, they demonstrate higher rates of niche evolution and expand into different climatic conditions than those of their diploid congeners. In contrast, autopolyploids show lower rates of niche evolution, occupy ecological niches similar to their ancestors and are restricted to less competitive and peripheral geographic areas.
Conclusions:
Hybridization thus seems advantageous by promoting ecological niche evolution and more readily allowing escape from competitive exclusion.
... During the last decade, many genus-and species-level studies of the Alysseae dealt with (micro) evolution, origin of polyploids, phylogeography, population genetics, taxonomic diversity or nomenclature (Iljinska 2005;Ortiz and Rodríguez Oubiña 2005;Ančev and Goranova 2006;Orcan 2006;Wesche et al. 2006;Ç elik et al. 2007;Iljinska et al. 2007;Avetisian 2009;Orcan and Binzet 2009;German 2010German , 2012bGerman , 2014aGerman and Al-Shehbaz 2010;Cecchi 2011;Knjasev 2011;Marhold et al. 2011;Meyer 2011;Pakravan et al. 2011;Š paniel et al. 2011a, b, 2012aÇ etin et al. 2012;Rusterholz et al. 2012;Yılmaz 2012;Al-Shehbaz 2013;Cecchi et al. 2013;Kavousi et al. 2014;Magauer et al. 2014;Ranjbar et al. 2014;Rešetnik et al. 2014;Zozomová-Lihová et al. 2014). Other studies in Alysseae focused on heavy-metals tolerance and uptake and potential for phytoremediation and phytomining applications (e.g., Cecchi et al. 2013;Adamidis et al. 2014;Bani et al. 2015;Ghaderian et al. 2015;Morais et al. 2015; and references therein). ...
... The generic and species concepts of the tribe Alysseae adopted in the present paper reflect the most recent phylogenetic, taxonomic, and nomenclatural studies at the levels of tribe and above (Warwick et al. 2008;Jaén-Molina et al. 2009;Al-Shehbaz 2012;Rešetnik et al. 2013), as well as at the levels of genera and species (German 2010(German , 2012a(German , b, 2014aGerman and Al-Shehbaz 2010;Cecchi 2011;Marhold et al. 2011;Španiel et al. 2011a, b, 2012aCecchi et al. 2013;Magauer et al. 2014;Rešetnik et al. 2014;Zozomová-Lihová et al. 2014). Part of the decisions was also made based on our yet-to-be-published studies focusing on Hormathophylla (E. ...
Supplementary material 1 Online Resource 1. List of tables and fields in the AlyBase database.
... During the last decade, many genus-and species-level studies of the Alysseae dealt with (micro) evolution, origin of polyploids, phylogeography, population genetics, taxonomic diversity or nomenclature (Iljinska 2005;Ortiz and Rodríguez Oubiña 2005;Ančev and Goranova 2006;Orcan 2006;Wesche et al. 2006;Ç elik et al. 2007;Iljinska et al. 2007;Avetisian 2009;Orcan and Binzet 2009;German 2010German , 2012bGerman , 2014aGerman and Al-Shehbaz 2010;Cecchi 2011;Knjasev 2011;Marhold et al. 2011;Meyer 2011;Pakravan et al. 2011;Š paniel et al. 2011a, b, 2012aÇ etin et al. 2012;Rusterholz et al. 2012;Yılmaz 2012;Al-Shehbaz 2013;Cecchi et al. 2013;Kavousi et al. 2014;Magauer et al. 2014;Ranjbar et al. 2014;Rešetnik et al. 2014;Zozomová-Lihová et al. 2014). Other studies in Alysseae focused on heavy-metals tolerance and uptake and potential for phytoremediation and phytomining applications (e.g., Cecchi et al. 2013;Adamidis et al. 2014;Bani et al. 2015;Ghaderian et al. 2015;Morais et al. 2015; and references therein). ...
... The generic and species concepts of the tribe Alysseae adopted in the present paper reflect the most recent phylogenetic, taxonomic, and nomenclatural studies at the levels of tribe and above (Warwick et al. 2008;Jaén-Molina et al. 2009;Al-Shehbaz 2012;Rešetnik et al. 2013), as well as at the levels of genera and species (German 2010(German , 2012a(German , b, 2014aGerman and Al-Shehbaz 2010;Cecchi 2011;Marhold et al. 2011;Španiel et al. 2011a, b, 2012aCecchi et al. 2013;Magauer et al. 2014;Rešetnik et al. 2014;Zozomová-Lihová et al. 2014). Part of the decisions was also made based on our yet-to-be-published studies focusing on Hormathophylla (E. ...
Database of published chromosome numbers and ploidy-level estimates of the tribe Alysseae is presented, together with the revised generic concept and the list of accepted names, to reflect the most recent taxonomic and phylogenetic studies in Alysseae. It is available on-line at www.alysseae.sav.sk. The tribe encompasses 24 genera and 277 species. Chromosome numbers and/or ploidy levels are known for 171 out of 297 recognized taxa. Of these, 95 (55.6 %) taxa are diploids, 43 (25.1 %) are polyploids, and 33 (19.3 %) involve both diploids and polyploids. The most common base chromosome number in the tribe is x = 8 and less frequent is x = 7. The highest variation in base chromosome numbers (x = 7, 8, 11, 15) is found in the genus Hormathophylla. A key to all genera and descriptions of the two new genera Cuprella and Resetnikia are presented. Many new nomenclatural combinations, mainly in the re-established Odontarrhena (77), are proposed.
... The present study described the comparative micromorphological features of 15 Korean irises for the first time. The results of LM and SEM microscopic analysis revealed useful and reliable leaf micromorphological traits of economically important plant families (Choi, Kim, & Jang, 2020b;Gul et al., 2019;Kandemir et al., 2019;Kim et al., 2021;Klimko et al., 2018;Kong & Hong, 2019;Lima et al., 2020;Magauer et al., 2014;Tabaripour et al., 2022). The leaf characteristics of the investigated Korean irises showed great diversity in the leaf margin, epidermal cell outline, stomatal size, and the occurrence of abnormal stomata (Table 2). ...
The genus Iris L., comprising approximately 210 species, is one of the most species‐rich genera in the family Iridaceae. In this study, the first comprehensive leaf micromorphological characters of Korean irises were studied using light and scanning electron microscopy. Our objective was to evaluate the foliar micromorphological characteristics (namely epidermal cells, stomata types, and guard cell size) of Korean Iris taxa in a systematic context. All the investigated Korean Iris taxa had amphistomatic or hypostomatic leaves with anomocytic stomatal complexes. Guard cell length varied among species, ranging from 24.8 μm (I. rossii) to 56.0 μm (I. domestica). Although the presence of papillae on the outer periclinal wall is not of taxonomic significance, leaf margin pattern, guard cell size, and sunken stomata type were useful for species‐level identification of Korean Iris species. The occurrence of polymorphic stomatal types was reported here for the first time, and the correlation between genome size and epidermal guard cell length was discussed. Leaf micromorphological characters of Korean Iris species are comprehensively described using scanning electron microscopy and light microscopy. The occurrence of polymorphic stomatal types in Korean irises was described here for the first time. The leaf micromorphological features were taxonomically relevant, increasing our understanding of the systematic relationships among Korean irises.
... Plant ecologists have been interested in the growing strategies of scree plants for a long time, with a variety of adaptive typologies having been described since the early 20 th century (see Schröter 1926;Jenny-Lips 1930;and, later, Somson 1984). In addition, as their habitats act as small terrestrial islands, many scree plants are frequently stenochorous or endemic (Deil 1999) and, for this reason, they have long fascinated plant systematists (see, recently, Zhang et al. 2011;Magauer et al. 2014). Plant sociologists have also investigated scree communities for a long time and, in recent decades, a considerable number of phyto-the Ligurian-Emilian Apennines to the northwest and the Tuscan-Emilian Apennines to the southeast. ...
... muelleri in Sardinia (Carnicero et al., 2019). Its characteristic morphology and ecology are the main grounds for recognizing it as a distinct subspecies, thus following Magauer et al. (2014), who recognized morphologically and ecologically distinct Alyssum wulfenianum Willd. subsp. ...
The Balkan Peninsula is a hotspot of European biodiversity, harbouring many endemic species. Cerastium decalvans is a heteroploid species endemic to mountainous areas throughout the Balkan Peninsula. It is morphologically extremely variable, and multiple infraspecific taxa have been described. Mostly tetra-, octo- and hexadecaploids have been reported, but their distribution and relationship to morphological differentiation remain unknown. To disentangle relationships among 62 populations sampled across the distribution of the species, we applied an integrative approach. Using flow cytometry, we show that tetraploids are the most widespread cytotype, whereas octoploids are limited to the south-east of the distribution area and hexadecaploids occur mostly in high mountains of the central–eastern Balkan Peninsula. The main genetic break revealed by AFLPs separates uniformly tetraploid populations from the Dinaric Mountains in the north-west of the distribution area from the south-eastern populations. Based on our data we hypothesize multiple (auto)polyploidization events leading to the origin of octoploid populations and two allopolyploidization events leading to the origin of hexadecaploids. By combining genome size, AFLP and morphological data, we suggest recognition of five subspecies, of which we here describe hexadecaploid C. decalvans subsp. doerfleri subsp. nov. endemic to the Albanian Alps. In addition, the presence of several phylogenetic lineages and multiple ploidies with pronounced morphological variability in the southern and eastern Balkan Peninsula points to pronounced environmental stability of this area throughout the Quaternary, enabling survival and divergence in situ, and further supports the role of the Balkans as a sanctuary of plant diversification.
... Удосконалення методів сканувальної електронної мікроскопії та інтенсивний розвиток молекулярно-біологічних досліджень стали потужним стимулом для конкретизації будови трихом і розширення таксономічної й діагностичної інтерпретації їхніх структурних особливостей. Як результат -описані нові типи волосків, деталізована структура трихом багатьох видів, родів та триб в повному обсязі чи в межах окремих регіонів (Ilyinska, 2003;Ilyinska and Shevera, 2003a, b;Abdel, 2005;Ančev and Goranova, 2006;Beilstein et al., 2006Beilstein et al., , 2008Spaniel et al., 2012;Fuentes-Soriano and Al-Shehbaz, 2013;Magauer et al., 2014;Mousavi and Sharifi-Rad, 2014;Mirzadeh et al., 2015). Тепер велику увагу приділяють дослідженню розвитку трихом Brassicaceae на молекулярному та генетичному рівнях (Pattanaik et al., 2014;Mazie and Baum, 2016;Doroshkov et al., 2019;Chopra et al., 2019;Hülskamp, 2019;Walden et al., 2020a). ...
Species of the Brassicaceae family (crucifers), which are of great scientific and practical importance, are inherent by a wide variety of trichome structures. Trichomes – specialized cells of the epidermis, modulate the response of plants to biotic and abiotic stresses. We investigated the structural diversity of trichomes and the features of pubescence of all (252 species, 73 genera) Brassicaceae species of the flora of Ukraine. Trichomes were studied on living plants and based on materials from seven herbaria, as well as on the basis of analysis of literature data. Stereoscopic and electronic scanning (JSM-6060 LA) microscopes were used in this investigation. To describe the structural diversity of trichomes, an original four-level hierarchical classification was developed, taking into account a complex of features, including functional specificity (covering or glandular), the nature and degree of hair branching, as well as the features of the orientation of their rays. The pubescence of plants was divided into isomorphic (consists of one type of trichomes) and heteromorphic (formed by two or more types of hairs with or without glandular structures). Hairs are completely absent in 23 species of 15 genera of the flora of Ukraine. Isomorphic pubescence is characteristic of the most (170 species) cruciferous plants and is represented by simple (120 species), Malpighian (23 species), stellate (23 species), dendroid (3) and fork-shaped (1 species) trichomes. The composition of heteromorphic pubescence is dominated by a combination of simple and fork-shaped hairs: it is observed in 44 species. There are glandular structures in the pubescence of 14 species. The structural diversity of Brassicaceae trichomes correlates, in general, with the temperate continental climate of Ukraine. Species without hairs or pubescent with simple trichomes, including those in combination with fork-shaped hairs, are observed in biotopes with sufficient moisture, optimal insolation, and satisfactory soil quality. Species with dense branched trichomes inhabit arid biotopes with intense
insolation, insufficient moisture, and poor substrate. In the flora of Ukraine, the evolutionary-phylogenetic line LII included non-pubescent species or those with simple hairs. The cruciferous line LI is characterized by isomorphic and heteromorphic pubescence. In species LIV, heteromorphic pubescence predominates. Glandular structures are observed in the heteromorphic pubescence of taxa of line LIII.
... The micromorphology of leaf and floral indumentum as well as pollen exine ornamentation are traits widely utilized by plant systematists because they may provide important diagnostic characters for the differentiation of plant groups at different taxonomic levels (Choi, Kim, & Jang, 2020;Gul et al., 2019;Jang, Lee, & Hong, 2014;Klimko, Nowi nska, Wilkin, & Wiland-Szyma nska, 2018;Kong & Hong, 2019;Magauer, Schönswetter, Jang, & Frajman, 2014;Moon, Hong, Smets, & Huysmans, 2009;Park, Yang, Song, & Moon, 2020). Despite the taxonomic importance of micromorphological characters in the family Colchicaceae Membrives, Pedrola-Monfort, & Caujapé-Castells, 2003;Tomaszewski & Zieli nski, 2014), only a limited number of micromorphological studies have been conducted in the genus Disporum (Chao & Tseng, 2019;Lee, 1979;Lee & Yeau, 1990;Wang, Gu, Zhao, & Liu, 2018). ...
The genus Disporum Salisb. is widely distributed in East Asia, yet phylogenetically relevant morphological traits useful for differentiating many of the small, perennial, herbaceous species remain poorly described. To address this, leaf, floral, pollen, and orbicule micromorphology of four Korean Disporum species was investigated using light and scanning electron microscopy. All Korean Disporum species examined had hypostomatic leaves, with anomocytic stomatal complexes found only on the abaxial epidermis. Guard cell length varied among species, ranging from 44.30 μm in D. viridescens to 53.49 μm in D. uniflorum . The epidermal cells of the investigated Disporum taxa had sinuate anticlinal cell walls on both adaxial and abaxial surfaces. The surface of the guard and subsidiary cells were either smooth with weak striations or had strongly wrinkled striations. The pollen grains of all Korean Disporum taxa were monads, monosulcate with granular aperture membranes, subprolate to prolate in shape with microreticulate or verrucate exine surfaces. The mean size of pollen grains ranged from 46.38 to 49.92 μm in polar length and from 34.39 to 39.58 μm in equatorial diameter across species. Sexine ornamentation was a taxonomically relevant trait for differentiating Korean Disporum taxa. Additionally, the presence of orbicules as well as the orbicular characters (e.g., size, shape, ornamentation, and association pattern) are described for the first time in species from this genus. The present investigation of leaf and floral micromorphology using light and scanning electron microscopy provides valuable information for the taxonomic differentiation and identification of Disporum species in Korea.
Research Highlights
A detailed micromorphological description of leaf, floral characters (tepal, stigma, style), pollen and orbicule is provided for Korean Disporum species using scanning electron microscopy (SEM) and light microscopy (LM).
The presence of orbicules and their taxonomic implications in Korean Disporum species are described for the first time.
Phylogenetically informative pollen and orbicule micromorphological characters are described, improving understanding the systematic relationships of Korean species in the genus Disproum .
... Whereas the taxonomy and evolutionary history of the A. montanum-A. repens species complex have been thoroughly explored in a series of recent studies (e.g., Španiel et al., 2011, 2017a,b, 2019Magauer et al., 2014;Zozomová-Lihová et al., 2014Arrigo et al., 2016;Melichárková et al., 2017), little is known about the phylogenetic relationships and speciation processes of the annual taxa. Here, we attempted to fill this gap by exploring the evolutionary history of all 16 annual taxa of Alyssum reported in Europe, some of which extend also to northern Africa or Asia (see Table 1). ...
The Mediterranean Basin is a significant hotspot of species diversity and endemism, with various distribution patterns and speciation mechanisms observed in its flora. High species diversity in the Mediterranean is also manifested in the monophyletic lineage of Alyssum annuals (Brassicaceae), but little is known about its origin. These species include both diploids and polyploids that grow mainly in open and disturbed sites across a wide elevational span and show contrasting distribution patterns, ranging from broadly distributed Eurasian species to narrow island endemics. Here, we investigated the evolution of European representatives of this lineage, and aimed to reconstruct their phylogeny, polyploid and genome size evolution using flow cytometric analyses, chloroplast and nuclear high- and low-copy DNA markers. The origin and early diversification of the studied Alyssum lineage could be dated back to the Late Miocene/Pliocene and were likely promoted by the onset of the Mediterranean climate, whereas most of the extant species originated during the Pleistocene. The Aegean region represents a significant diversity center, as it hosts 12 out of 16 recognized European species and comprises several (sub)endemics placed in distinct phylogenetic clades. Because several species, including the closest relatives, occur here sympatrically without apparent niche differences, we can reject simple allopatric speciation via vicariance as well as ecological speciation for most cases. Instead, we suggest scenarios of more complex speciation processes that involved repeated range shifts in response to sea-level changes and recurrent land connections and disconnections since the Pliocene. In addition, multiple polyploidization events significantly contributed to species diversity across the entire distribution range. All seven polyploids, representing both widespread species and endemics to the western or eastern Mediterranean, were inferred to be allopolyploids. Finally, the current distribution patterns have likely been affected also by the human factor (farming and grazing). This study illustrates the complexity of evolutionary and speciation processes in the Mediterranean flora.
... This methodological approach of sample preparation can be quite easily performed in the field and additionally, it allows long-term sample storage in the frozen state. Importantly, it provides estimates of nuclear DNA content that are highly comparable to those obtained using fresh material (Kolář Although this method has been used for estimation of GS in laboratory conditions (Magauer et al. 2014;Frajman et al. 2015), it has only been field-tested by Kolář et al. (2012). ...
The extraordinary biodiversity of tropical regions has attracted many researchers. Despite an increasing number of genome size (GS) estimations, those of tropic flora remain poorly explored. In this study, we applied the glycerol-preserved nuclei protocol for GS estimation in the field conditions of a tropical rainforest in Brunei Darussalam, northern Borneo. Samples were prepared in the field following this protocol and subjected to the flow cytometry analysis in the laboratory approximately 1 month later. The glycerol-preserved nuclei protocol enabled us to perform GS estimations of thirty taxa of Euphorbiaceae s.l. (twenty taxa of Euphorbiaceae and ten taxa of Phyllanthaceae family, respectively), all representing first estimates of GS for respective taxa. We found 5.09-fold overall variation in GS, with the lowest value in Croton sp. (2C = 0.97 pg) and the highest value in Aporosa elmeri (2C = 4.94 pg). The vast majority of species presented very small GS (77%), while 23% of the species had small GS. Using available data of Euphorbiaceae s.l. from the Plant DNA C-values database, we also tested the correlations of GS with climate (tropical vs. temperate) and growth form (woody vs. herbaceous). Tropical taxa of Euphorbiaceae s.l. (incl. Euphorbiaceae s.s. and Phyllanthaceae) have significantly smaller GS values than temperate ones. No significant difference in GS between woody and herbaceous taxa was detected.
... repens complex. Whereas the taxononomic and evolutionary relationships of the latter group have been thoroughly examined by molecular and morphometric analyses (Španiel et al. 2011a, b, 2012a, b, 2017a, b, 2018, 2019, Magauer et al. 2014, Zozomová-Lihová et al. 2014, Arrigo et al. 2016, Melichárková et al. 2017, annual taxa have remained little explored. Our current molecular-systematic research of all European annual species of Alyssum (Cetlová et al., in preparation) will fill this gap and shed more light on their evolutionary history. ...
A recent study of European annual taxa of Alyssum has revealed that A. simplex includes two cytotypes (diploid and tetraploid) which differ in genetic markers, evolutionary history, and monoploid relative genome size. In this paper we present a new taxonomic treatment of A. simplex in which we treat the two cytotypes as two separate species. We select and discuss suitable names for both taxa (diploid A. simplex and tetraploid A. collinum), examine their morphological differences and survey their geographic distribution. In addition, we compare both cytotypes with the morphologically similar and genetically related species A. strigosum and designate lectotypes and a neotype of several relevant names.
... Absolute genome size was 2C = 1.50 pg for diploids and 2C = 2.98 pg for tetraploids. The value of tetraploids exceeds the 2C value measured by Magauer et al. (2014) for Alyssum montanum s.l. populations of Dinaric Mountains (2C = 2.52 pg) by 15.4 %. ...
The author describes the adaptation to metal contaminated soils of various populations of Alyssum montanum L. (Brassicaceae) by conducting a large scale tolerance experiment, cytotype characterization, population genetic analyses and an exploratory genome scan. Metalliferous soils are a challenge for plant life as they force species to develop tolerance mechanisms to prevent toxic effects of metal ions. Therefore, plants adapted to metalliferous soils provide model systems for examining edaphic adaptation and its role in the formation of ecotypes as well as ecological speciation.
A. montanum was proven to be a pseudometallophyte (plants that can tolerate a high metal content in their environment, but also thrive under normal conditions). Among populations different degrees of metal tolerance have been observed, ranging from metal sensitive to highly metal tolerant. Metal tolerance repeatedly evolved in various populations, whereby the tolerance is specific to the soil metal composition of the population site. Similar metal tolerance and similar differentiation in candidate loci in tolerant diploid and tetraploid populations indicate a parallel evolution of metal tolerance across cytotypes. Furthermore, populations of non-metal sites are probably able to develop tolerance within a short time period. Evidence was found for a local or even microgeographic adaptation in both cytotypes. These findings offer the opportunity for subsequent analyses to explore genetic architecture of metal tolerance and reproductive isolation in a non-model species in connection with edaphic differentiation.
... Most of the perennial species belong to the Alyssum montanum-A. repens complex, which has been subject to numerous molecular-systematic and morphometric studies carried out over the last decade (Španiel et al. 2011a, b, 2012a, b, 2017a, b, 2018a, b, Magauer et al. 2014, Zozomová-Lihová et al. 2014, Melichárková et al. 2017. These studies have thoroughly mapped the genetic and morphological variation of the species complex across a major part of Europe, revealed its evolutionary history and led to many taxonomic changes. ...
Alyssum austrodalmaticum was originally described as an endemic species from southern Croatia. It has been considered a dubious taxon because its holotype specimen got lost and because of the scant information contained in the protologue. To settle the interpretation of the name and its application to other Western Balkan populations, a neotype was recently designated. Soon after, the lost holotype specimen was accidentally rediscovered. It is in agreement with the (now superfluous) neotype and the most recent circumscription of the species. Here we present the holotype, summarize the previous uncertainty surrounding this taxon and list all its herbarium specimens from Croatia and adjacent regions deposited in the herbaria CNHM, ZA, ZAHO and ZAGR.
... subsp. wulfenianum which grows on river gravel beds in the Alps (Magauer et al., 2014). ...
Alyssum cuneifolium has been recognized as a perennial alpine species growing in five isolated European mountain ranges: the Pyrenees, Western Alps, Apennines, Pirin Mts and Mt Smolikas. Recent molecular systematic studies revealed that the disjunct populations from distant mountains are not closely related and belong to five independent species: A. cacuminum (Spain, Pyrenees), A. cuneifolium (Italy, Apennines), A. flexicaule (France, Western Alps), A. pirinicum (Bulgaria, Pirin Mts), and A. spruneri (Greece, Mt Smolikas). The present study brings the thorough morphometric analysis of the segregated taxa. We found minor morphological differences between them. Whereas A. pirinicum can be clearly distinguished, the other taxa are recognizable only at the level of population means of investigated characters. The morphological similarity of these distantly related species is obviously the result of adaptation to similar high‐alpine scree habitats. It is not clear, however, whether this adaptation is environmentally controlled or whether it is also genetically fixed and whether it reflects parallel evolution towards similar morphotypes. The observed morphological patterns and their assumed correlation with environmental factors are discussed using examples from other Alyssum taxa. Three different ploidy levels have been reported for the species under study. In the present article, we examine variation in relative nuclear genome size. The Alpine and Pyrenean species have larger relative monoploid genome sizes than the Apennine and Balkan ones, probably reflecting the evolutionary history of the group. A nomenclatural account of the study species is presented, and lectotypes of A. cuneifolium and of two other names are selected.
... Best explored are the perennial species of the diploid-polyploid Alyssum montanum-A. repens complex (Španiel et al. 2011a, b, 2012a, b, Magauer et al. 2014, Zozomová-Lihová et al. 2014, Melichárková et al. 2017, Španiel et al. 2017a. The greatest species diversity of Alyssum, besides Anatolia and adjacent regions of the Middle East, is found in the mountains of southern Europe. ...
Alyssum rossetii, a stenoendemic madwort discovered on a mountain slope in the Valpelline valley (northern part of the Aosta Valley in the Pennine Alps), is described here as a new species. It is a perennial that is morphologically close to the Alyssum montanum-A. repens complex, with several hitherto neglected peculiar morphological characters. Here we present a full description of the new taxon, including information on its chromosome number, genome size and ecology, as well as a detailed morphological comparison of the new species with four related taxa occuring in the broader region, namely A. flexicaule, A. montanum, A. orophilum and A. rhodanense. Besides morphological differences, the new species also conspicuously differs from the other taxa in relative monoploid genome size. According to the IUCN Red List categories and
criteria, it should be classified as Endangered.
... Morphology and taxonomy-Several previous taxonomic studies of representatives of the tribe Alysseae (e.g. Španiel et al. 2011a, b, 2012a, b, 2017b, Zozomová-Lihová et al. 2014, Magauer et al. 2014) have shown that morphological differences between related (but clearly genetically different and allopatric) taxa are sometimes only minute. Besides, some morphological characters appear to be at least partly influenced by the environment. ...
Odontarrhena tortuosa is a herbaceous species occurring in steppe and rocky habitats of Eurasia. The present study is focused on the cytogeography and morphological variation of the species’ populations growing in the Pannonian basin (Central Europe), which represents the westernmost part of its distribution area. Flow cytometric analyses have revealed the existence of tetraploid populations, which are reported here for the first time for Central Europe. We analysed the morphological variation of 329 individuals from Slovakia, Hungary and Serbia by multivariate morphometric methods to evaluate morphological differences between two cytotypes (diploids and tetraploids), between the subspecies (O. tortuosa subsp. tortuosa and O. tortuosa subsp. heterophylla) and between populations growing in three regions differing in the type of substrate (rocks, sand dunes and sandy and rocky screes). Although we have not found any clear morphological differences between the cytotypes, we have confirmed several previously reported morphological differences between the two subspecies, which occur in regions differing in the type of substrate. Flow cytometric data also indicate certain differences in monoploid genome size between all groups of populations under comparison. Populations from Serbia differ from other populations of O. tortuosa subsp. tortuosa in morphology and genome size, but due to a lack of data on the genetic variation of the species we suggest no change in taxonomy. For the identification of the two subspecies, we present an updated determination key.
... 105 species distributed throughout Europe, Asia, northern Africa and northern America (Španiel et al. 2015). Of them, fourteen specific and subspecific taxa are currently recorded for Italy (Conti et al. 2005, 2007, Španiel et al. 2011, Magauer et al. 2014, Bartolucci & Conti 2016. Based on available literature (Conti et al. 2005(Conti et al. , Španiel et al. 2011(Conti et al. , 2012, four units occur in Calabria: A. alyssoides (Linnaeus 1753: 652) Linnaeus (1759, A. diffusum Tenore (1812: 37) subsp. ...
Alyssum doerfleri is recorded for the first time in Italy from Monte Sellaro, Pollino National Park (southern Apennines, Calabria). Macro- and micro-morphology (including SEM study of trichomes) and, karyology (2n = 16) of the Italian plants are congruent with the data available for Balkan populations. Chorological and conservation features of this species are presented and discussed.
... L. Bernardo, G. Maiorca Il genere Alyssum L. (Brassicaceae) consta di circa 195 specie distribuite in Europa, Asia e Nord America ( Bartolucci, Conti 2016). In Italia sono attualmente segnalate 14 entità ( , 2007, Španiel et al. 2011, Magauer et al. 2014, Bartolucci, Conti 2016). Durante la revisione di campioni d'erbario di Brassicaceae depositati in CLU e presenti anche nella collezione privata Maiorca-Caprio, abbiamo esaminato materiale attribuibile al genere Alyssum, non inquadrabile in alcuna delle specie sinora note per l'Italia. ...
... Saxifragoideae and in particular among those of the S. saxifraga group, the aim of this study is to establish a firm phylogenetic framework and to disentangle the relationships within this section using nuclear ribosomal internal transcribed spacer (ITS) and plastid rps16 sequences as well as amplified fragment length polymorphisms (AFLPs). Both sequenced DNA regions have proven informative in phylogenetic studies of tribe Sileneae (e.g., Oxelman & Liden, 1995;Oxelman & al., 1997;Frajman & Oxelman, 2007;Aydin & al., 2014), whereas AFLPs are widely used in phylogeographic studies, successfully resolving relationships at lower taxonomic levels (e.g., Kuzmanović & al., 2013;Magauer & al., 2014;Ronikier & Zalewska-Gałosz, 2014). Specifically, we (1) investigate whether phylogenetic relationships within the S. saxifraga group correspond to traditional taxonomy or rather to geographic proximity as previously inferred for other intricate species groups with high diversity in the Balkan Peninsula (e.g., Frajman & Oxelman, 2007), (2) explore their relationships to S. sect. ...
Out of ca. 700 species belonging to Silene, 15 to 35 were classified in S. sect. Saxifragoideae. This section has its highest diversity on the Balkan Peninsula, which was the most important European Pleistocene refugium. The most widespread of the species is S. saxifraga ranging from the Pyrenees to the Carpathians. Together with ten morphologically similar taxa it is often treated as the S. saxifraga group, but the relationships among the taxa are unclear and blurred due to the occurrence of transitional forms. In this study, we used sequences of the nuclear ribosomal internal transcribed spacer (ITS) and the plastid rps16 intron as well as amplified fragment length polymorphisms (AFLPs) to elucidate phylogenetic relationships among the taxa belonging to—or hypothesized to be closely related to—S. sect. Saxifragoideae, covering the section's entire geographical range. Phylogenetic analyses of 112 populations belonging to 33 taxa clarified previous classifications and showed that S. cephallenia, S. congesta, S. linoides, S. multicaulis, S. schwarzenbergeri and S. waldsteinii are clearly differentiated from all other taxa, which in turn form the newly circumscribed S. saxifraga group. Phylogenetic relationships within the latter are unresolved, and are governed by geographic proximity rather than by taxonomic identity. This is likely a result of recent rapid radiation and range expansion, as well as of convergent morphological evolution triggered by similar environmental selection pressures. The southern parts of the Balkan Peninsula are the centre of genetic diversity of the group, underlining the area's importance as a sanctuary of diversification of European biota.
... Thirteen Alyssum taxa are currently recorded in Italy (CONTI et al. 2005, 2007, ŠPANIEL et al. 2011a, b, 2012MAGAUER et al. 2014 (ŠPANIEL et al. 2012, PERUZZI et al. 2014, PERUZZI et al. 2015. Alyssum montanum L. has been excluded from the flora of Italy (ŠPANIEL et al. 2011a(ŠPANIEL et al. , b, 2012, A. ligusticum Breistr. ...
The occurrence of Alyssum desertorum, a species belonging to A. sect. Alyssum, is reported for the first time in Italy. It was found in Abruzzo (central Italy) in the territory of National Park of Gran Sasso and Laga mountains and surrounding areas. Morphological similarities with the other taxa recorded in Italy belonging to A. sect. Alyssum are briefly discussed. Information about the typification of the name, habitat, phenology and distribution in Italy are also provided.
... This method has been repeatedly shown to be a useful tool in similar studies (e.g. Kardolus, Van Eck & Van den Berg, 1998;Werres et al., 2001;Bottini et al., 2002;Martínez-Ortega et al., 2004;Meudt & Clarke, 2007;Van den Berg & Groendijk-Wilders, 2007;Duminil et al., 2012;Prebble, Meudt & Garnock-Jones, 2012;Paul, Nandi & Palni, 2013;Magauer et al., 2014). More specifically, our aims are as follows: (1) to test whether the species traditionally named F. desertorum is monophyletic; (2) to assess the taxonomic identity of those Filago from north-western Morocco and south-eastern Spain with hairs at the margin of the internal paleae. ...
Filago desertorum, as traditionally circumscribed, is a species that shows high levels of morphological variation. Previous authors have even suggested that this taxon should represent a heterogeneous assembly of true biological species. A taxonomic revision of the species included in the Filago desertorum clade was performed, and amplified fragment length polymorphism (AFLP) markers were used to explore the phylogenetic relationships among the members of the clade. Three species are recognized in the group, one of which is newly described. A full description of F. castroviejoi sp. nov., a complete nomenclatural treatment and a key to the species included in the clade are provided. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, ●●, ●●–●●.
... Milne and Abbott (2002) proposed a refugium with a Tertiary relict flora (plant species predating Quaternary climate oscillations) to exist in southeast Europe, which largely coincides with the Balkan Peninsula, with the latter being recognized as a biodiversity hot spot comprising a number of glacial refugia (Gaston and Rhian 1994;Médail and Diadema 2009;Hewitt 2011). Some studies have been published on plants of the western Balkan Peninsula (e.g., Liber et al. 2008;Siljak-Yakovlev et al. 2008;Perović et al. 2012;Lakušić et al. 2013;Grdiša et al. 2014), including phylogeographic studies (e.g., Frajman and Oxelman 2007;Surina et al. 2011;Kutnjak et al. 2014;Magauer et al. 2014); few include populations from the eastern Balkan Peninsula in larger studies (Puşcaş et al. 2008;Albach et al. 2009; Bardy et al. 2010), and none focuses on narrow endemics in the latter area exclusively. Paleoendemics (narrow endemics with a long evolutionary history, having a much wider distribution in the past) can serve here as model systems for gaining deeper insight into the effects of history and glaciations on plant species distribution, including expansion and recolonization of plants in Europe spanning the Tertiary. ...
Premise of research. Even though the Balkan Peninsula is a biodiversity hot spot in southeastern Europe harboring many endemic plants, very little is known about the temporal extent of the phylogeographic history and the contemporary genetic diversity of the endemics there. Haberlea rhodopensis is one of the European Gesneriaceae species occurring in this region and represents appropriate study material to address these questions. Methodology. We generated fossil-dated molecular phylogenies (atpB-rbcL, trnH-psbA, trnLF, ITS) across the Lamiales to determine the origin and age of H. rhodopensis and conducted phylogeographic (trnH-psbA, ITS) and population genetic (ISSRs) analyses on 17 populations from Bulgaria and Greece, covering the entire distribution range of the species, to investigate their biogeographic history, present-day genetic diversity, and differentiation levels. Pivotal results. The European Gesneriaceae genera have a Tertiary origin in the early Oligocene, while the Haberlea lineage emerged in the late Oligocene. Extinctions appear to have marked the history of the genus for a long period of time, and the extant populations diverged in the late Pleistocene. A significant differentiation was apparent between populations from Bulgaria, that is, the Balkan Mountains in the north and the Bulgarian side of the Rhodopi massif in the south, but there was an even stronger differentiation between the latter and populations from Greece. This might be explained by the Rhodopi massif representing a barrier to gene flow, enforced during the Last Glacial Maximum, during which populations descended on opposing north- and south-facing mountain slopes. Conclusions. Haberlea represents an ancient lineage with recent diversification. The extant populations are of recent origin and indicate glacial refugial areas in Bulgaria and Greece. This study sheds light on historic and current phylogenetic and phylogeographic events that shaped the flora of the Balkan Peninsula, an area that has long been recognized for its species diversity and richness. Our data suggest that it may have acted as a persistent refugial area in southeast Europe since the mid-Tertiary.
A little more than 10% of the vascular plant flora native to the European Alps is endemic to this area. It has long been noticed that the distribution of endemics across the Alps is very uneven. While most endemics are found along the southern edge of the Alps, with some also on its western, eastern, and northeastern edges, the northern edge of the Alps more or less between Lake Geneva in the west and Lake Traun in the east harbours almost no endemics. The distribution of endemics in the Alps has often been related to the location of glacial refugia. Accordingly, the virtual absence of endemics from the northern edge of the Alps has been explained with the unsuitability of climatic conditions for glacial survival of alpine plants there. After discussing evidence for the existence of glacial refugia for alpine species along the northern edge of the Alps and north of the Alps, I will examine how these refugia differed from refugia along the southern edge of the Alps. I conclude that the uneven distribution of endemics in the Alps is best explained by the different climate through time north and south of the Alps. These climatic differences affected the spatial structure and extent of refugia, the length of isolation of refugial populations, and selective conditions in refugia.
The major response of organisms to the climatic oscillations of the Quaternary was migration. Considering alpine plants, migration into low elevation cold-stage refugia took place in glacial periods, and re-migration into high elevation areas in interglacial periods and the Holocene. The present review examines the possibility that populations at the rear edge of re-migrating species persisted and evolved in the area of cold-stage refugia. Here, they would be faced with increasingly warm conditions and strong competition from other species re-migrating into the cold-stage refugial area. For the flora of the European Alps, I identified 13 species or subspecies pairs in which one taxon of a pair may represent an evolutionary derivative of persisting rear-edge populations, whereas the other represents populations which tracked their niche and re-migrated into high elevation areas. If confirmed by further analyses, these taxon pairs would illustrate that adaptive evolutionary divergence in Quaternary interglacials and the Holocene is possible, and most likely can persist through one or several much longer glacial periods.
Red list of Austrian vascular plants.
Iris ruthenica Ker Gawl. and I. uniflora Pall. ex Link, which are rare and endangered species in Korea, possess considerable horticultural and medicinal value among Korean irises. However, discrimination of the species is hindered by extensive morphological similarity. Thus, the aim of the present study was to identify discriminating features by comparing the species’ complete plastid genome (i.e., plastome) sequences and micromorphological features, including leaf margins, stomatal complex distribution (hypostomatic vs. amphistomatic leaves), anther stomata density, and tepal epidermal cell patterns. Plastome comparison revealed slightly divergent regions within intergenic spacer regions, and the most variable sequences, which were distributed in non-coding regions, could be used as molecular markers for the discrimination of I. ruthenica and I. uniflora. Phylogenetic analysis of the Iris species revealed that I. ruthenica and I. uniflora formed a well-supported clade. The comparison of plastomes and micromorphological features performed in this study provides useful information for elucidating taxonomic, phylogenetic, and evolutionary relationships in Iridaceae. Further studies, including those based on molecular cytogenetic approaches using species specific markers, will offer insights into species delimitation of the two closely related Iris species.
Quaternary climatic oscillations are major determinants of biodiversity in Europe. Yet their consequences have rarely been assessed in species whose ranges were continuous in the cold spells but then became fragmented by expanding forest in the mid-Holocene into so-called interglacial refugia. The Galium pusillum group (Rubiaceae), occupying various island-like habitats from the lowlands to the subalpine belt of Central Europe, is well suited for addressing the processes shaping genetic and cytological diversity of island populations and testing whether they leave distinct footprints in different habitat types. Using amplified fragment length polymorphism (AFLP) analysis and plastid sequences, we estimated the diversity and differentiation of 15 diploid and 44 tetraploid populations. Although the frequency of ploidy levels differed between low- and high-elevation stands, genetic diversity was homogeneous across various habitat types and elevations. Overall, high diversity probably reflects long-term local persistence of the group that was followed by fragmentation into isolated but probably stable populations that do not show signs of diversity loss. Moreover, hybridization pre-dating the contemporary fragmentation further increased overall diversity and was probably involved in the formation of a local subalpine endemic. In sum, our study shows that low-competition habitats of various substrates and elevations may play comparable roles in preserving distinct plant diversity.
Next generation sequencing has revolutionised biology. Restriction-associated DNA sequencing (RADseq) has primarily been used to study infraspecific relationships but has also been applied in multi-species phylogenomic analyses. In this study, we used a combination of phylogenomic (with RADseq data) and phylogenetic (with sequences of the nuclear internal transcribed spacer, ITS) methods to explore relationships within the taxonomically intricate Euphorbia seguieriana s. l., one of the most widespread Euphorbia taxa inhabiting zonal and extrazonal steppes from Iberia to Central Asia. In the inferred phylogenies the southeastern Balkan and Anatolian populations were clearly separated, supporting the distinction of E. niciciana from E. seguieriana at the species level. Within E. seguieriana, the populations from the Caucasus, Iran, and easternmost Anatolia were sister to all other populations based on RADseq, making necessary the description of a new, morphologically divergent subspecies, E. seguieriana subsp. armeniaca. Conversely, additional studies are needed to understand the status of E. seguieriana subsp. hohenackeri, which is sympatric with E. seguieriana subsp. armeniaca. Niche analyses indicated that differences in the climatic niche between E. niciciana and E. seguieriana are relatively small compared with the climatic differences between the regions over which they are distributed. Contrary to previous believes, E. niciciana and E. seguieriana are allopatric and have likely diverged during the Pleistocene in two different glacial refugia as suggested by distribution modelling. Euphorbia niciciana nowadays has a submediterranean distribution, occupying habitats that are slightly warmer, moister, and less seasonal in temperature but more seasonal in precipitation than E. seguieriana, a characteristic species of continental steppes. Using flow cytometry, we demonstrate that the relative genome sizes of E. niciciana and E. seguieriana differ significantly. Additionally, multivariate morphometric analyses of 56 morphological characters indicated clear morphological divergence of the two species. Importantly, we also provide a revised taxonomic treatment including formal nomenclatural changes, an identification key and species descriptions. Our study demonstrates that an integrative approach, combining modern phylogenomic methods with traditional phylogenetic, cytogenetic, environmental and morphological analyses can result in satisfactorily resolved relationships in intricate groups of closely related species. Finally, phylogenetic inference using ITS sequences is still a useful tool for resolving relationships among the taxa at the species level, but the phylogenomic approach based on RADseq data certainly provides better resolution both among and within species.
This paper describes a botanical field trip in the area of the Aflenzer Bürgeralm (Styria, Northeastern Calcareous Alps, Hochschwab area) during the high flowering season from the end of June to the beginning of July. Starting from the Bürgeralm at 1555 m above sea level, the field trip leads over the Schönleiten plateau (1800 m) to the Höchstein (1741 m), continues to Zlacken, and leads along the edge of the Schönleiten plateau back to the Bürgeralm. Here we encounter a diverse mosaic of pasture grasslands, limestone lawns, rock vegetation, Krummholz, and remnants of a high montane larch forest. The flora is rich in endemics typical for the Northeastern Calcareous Alps.
Morphological classification of living things has challenged science for several centuries and has led to a wide range of objective morphometric approaches in data gathering and analysis. In this paper we explore those methods using apple cultivars, a model biological system in which discrete groups are pre-defined but in which there is a high level of overall morphological similarity. The effectiveness of morphometric techniques in discovering the groups is evaluated using statistical learning tools. No one technique proved optimal in classification on every occasion, linear morphometric techniques slightly out-performing geometric (72.6% accuracy on test set versus 66.7%). The combined use of these techniques with post-hoc knowledge of their individual successes with particular cultivars achieves a notably higher classification accuracy (77.8%). From this we conclude that even with pre-determined discrete categories, a range of approaches is needed where those categories are intrinsically similar to each other, and we raise the question of whether in studies where potentially continuous natural variation is being categorised the level of match between categories is routinely set too high.
By harbouring ca. 3500 native vascular plant species in an area of ca. 170 000 km², the European Alps represent a region of very high species diversity. Using the most recently published flora of the area and phylogenetic literature, I here review which proportion of the endemic flora of the Alps is the result of in situ diversification, i.e., of diversification in the area and (largely) restricted to the area. There exist only very few and mostly species-poor species diversifications in the Alps, accounting for ca. 1.2% of the native and for ca. 9% of the endemic flora of the Alps. In contrast to this, ca. 33% of the endemic species of the Alps belong to lineages widespread in the European Alpine System (EAS), comprising mainly the Pyrenees, Apennines, Carpathians, Dinarids and Balkans, in addition to the Alps. The rarity of Alpine species diversifications is hypothesised to reflect the Quaternary climatic history of the Alps where massive and repeated glaciations prevented the undisturbed evolution of species-rich lineages.
Senecio carniolicus (Asteraceae) is an intricate polyploid complex distributed in the European Alps (di-, tetra- and hexaploids)and Carpathians (hexaploids only). Molecular genetic, ecological, and crossing data allowed four evolutionary groups within S. carniolicus to be identified. Here, we establish that these four groups (two vicariant diploid lineages, tetraploids and hexaploids) are also morphologically differentiated. As a consequence, we draw taxonomic conclusions by characterizing four species, including the more narrowly circumscribed S. carniolicus (lectotypified here), the taxonomically elevated S. insubricus comb. nov. (lectotypified here), and the two newly described species S. disjunctus and S. noricus.
Range shifts (especially during the Pleistocene), polyploidisation and hybridization are major factors affecting high-mountain biodiversity. A good system to study their role in the European high mountains is the Doronicum clusii aggregate (Asteraceae), whose four taxa (D. clusii s.s., D. stiriacum, D. glaciale subsp. glaciale and D. glaciale subsp. calcareum) are differentiated geographically, ecologically (basiphilous versus silicicolous) and/or via their ploidy levels (diploid versus tetraploid). Here, we use DNA sequences (three plastid and one nuclear spacer) and AFLP fingerprinting data generated for 58 populations to infer phy-logenetic relationships, origin of polyploids—whose ploidy level was confirmed by chro-mosomally calibrated DNA ploidy level estimates—and phylogeographic history. Taxonomic conclusions were informed, among others, by a Gaussian clustering method for species delimitation using dominant multilocus data. Based on molecular data we identified three lineages: (i) silicicolous diploid D. clusii s.s. in the Alps, (ii) silicicolous tetraploid D. stir-iacum in the eastern Alps (outside the range of D. clusii s.s.) and the Carpathians and (iii) the basiphilous diploids D. glaciale subsp. glaciale (eastern Alps) and D. glaciale subsp. cal-careum (northeastern Alps); each taxon was identified as distinct by the Gaussian clustering , but the separation of D. glaciale subsp. calcareum and D. glaciale subsp. glaciale was not stable, supporting their taxonomic treatment as subspecies. Carpathian and Alpine populations of D. stiriacum were genetically differentiated suggesting phases of vicariance, probably during the Pleistocene. The origin (autopolyploid versus allopolyploid) of D. stiria-cum remained unclear. Doronicum glaciale subsp. calcareum was genetically and morphologically weakly separated from D. glaciale subsp. glaciale but exhibited significantly higher genetic diversity and rarity. This suggests that the more widespread D. glaciale subsp.
The role of glacial oscillations in shaping plant diversity has been only rarely addressed in endemics of formerly glaciated areas. The Galium pusillum group represents a rare example of an ecologically diverse and ploidy-variable species complex that exhibits substantial diversity in deglaciated northern Europe. Using AFLP and plastid and nuclear DNA sequences of 67 populations from northern, central, and western Europe with known ecological preferences, we elucidate the evolutionary history of lineages restricted to deglaciated areas and identify the eco-geographic partitioning of their genetic variation. We reveal three distinct endemic northern lineages: I) diploids from southern Sweden + the British Isles, II) tetraploids from southern Scandinavia and the British Isles that show signs of ancient hybridization between the first lineage and populations from unglaciated central Europe, and III) tetraploids from Iceland + central Norway. Available evidence supports a stepwise differentiation of these three lineages that started at least before the last glacial maximum by processes of genome duplication, inter-lineage hybridization and/or allopatric evolution in distinct periglacial refugia. We reject the hypothesis of more recent postglacial speciation. Ecological characteristics of the populations under study only partly reflect genetic variation and suggest broad niches of postglacial colonizers. Despite their largely allopatric modern distributions, the north-European lineages of the G. pusillum group do not show signs of rapid postglacial divergence, in contrast to most other northern endemics. Our study suggests that plants inhabiting deglaciated areas outside the Arctic may exhibit very different evolutionary histories compared to their more thoroughly investigated high-arctic counterparts. This article is protected by copyright. All rights reserved.
This article is protected by copyright. All rights reserved.
The Alyssum montanum–A. repens polyploid complex is a group of related perennial taxa with a diversity centre in the European (Sub)Mediterranean, controversial taxonomic treatments, and a poorly known evolutionary history. In the present study, morphological, ploidy level and genetic (AFLPs and chloroplast DNA sequences) data were collected to address the taxonomy and evolution of a sublineage of this complex distributed in southwestern Europe and Morocco. As a result, a new taxonomic treatment, differing substantially from recent concepts, is presented, including an identification key, synonymy and typifications. The recognition of several previously described but recently not accepted endemics is favoured (A. flexicaule, A. orophilum, A. rhodanense), whereas the existence of southern Iberian endemics is not supported. Most of the Iberian Peninsula is occupied by a single species for which the name A. fastigiatum is applicable. Populations from the summit areas of the Pyrenees represent a separate species, which is described here as A. cacuminum. Populations from coastal sand dunes in the Basque country (Bay of Biscay) and Galicia, recently recognised as two subspecies of A. loiseleurii, are elevated to species rank according to their genetic and morphological divergence. Alyssum atlanticum is resolved as a species confined to northern Africa and not reaching southern Spain. The distribution of A. montanum in a strict sense is much more restricted than previously reported, being delimited by the Pyrenees in the south, and the Alps in the northeast. The species complex studied here is composed of several polyploid stenoendemics confined to different mountain ranges or specific lowland habitats, and a few relatively widely distributed species. We infer that hybridisation and polyploidisation events, along with ecological and geographic isolation, have stimulated speciation in this complex. Hypotheses about the origin and evolutionary history of the species are discussed.
Chloroplast DNA sequences are a primary source of data for plant molecular systematic studies. A few key papers have provided the molecular systematics community with universal primer pairs for noncoding regions that have dominated the field, namely trnL- ...
Changes in chromosome number and structure are important contributors to plant evolution and speciation.
An excellent system in which to investigate the role of chromosomal changes, especially dysploidy and
polyploidy, in species diversification is Melampodium (Millerieae, Asteraceae), which contains a wide variety
of chromosome base numbers. We present detailed chromosomal information on numbers and karyotypes
obtained from 394 individuals in 111 populations of 39 Melampodium species and interpret it in the context of a recently developed phylogenetic hypothesis. The distribution of chromosome base numbers (including x=14, reported here for the first time) largely agrees with the circumscription of phylogenetic groups, with the
exceptions of x=10, which evolved twice independently, and x=11, the putative ancestral chromosome base
number still present in a number of distinct lineages. Polyploidy (tetra- and hexaploidy) is known from 17
species, 13 of which are exclusively polyploid, and includes autopolyploids and, more frequently, allopolyploids, with a hotspot in sect. Melampodium. Polyploid karyotypes usually do not undergo any obvious structural changes, but the presumably autotetraploid M. dicoelocarpum consistently has a reduced chromosome number (2n=4x�-2=46 instead of 2n=4x=48).
An ecological survey of metallophytes belonging to the Thlaspietum cepaeifolii plant community was carried out at the former Raibl lead and zinc mining site (Julian Alps, Italy). The aims of this work were to evaluate metal hyperaccumulation and to determine whether it was restricted to a single element or, instead, involved multiple elements. The concentrations of Cd, Pb, Tl and Zn were measured in specimens of Alyssum wulfenianum, Biscutella laevigata subsp. laevigata, Minuartia verna and Thlaspi rotundifolium subsp. cepaeifolium collected from native and mining soils, mine tailings and stream banks. Cadmium hyperaccumulation was not demonstrated, whereas in the case of Pb and Zn contradictory results were obtained. Thallium hyperaccumulation was strongly confirmed in B. laevigata subsp. laevigata (up to 32,661 mg kg of Tl in shoots and bioconcentration factor > 1). Surprisingly, this was also discovered in A. wulfenianum and M. verna (up to 1934 and 3632 mg kg of Tl in shoots, respectively, and bioconcentration factor >1). Multiple metal hyperaccumulation was verified in B. laevigata subsp. laevigata (Pb and Tl), M. verna and T. rotundifolium subsp. cepaeifolium (Pb, Tl, and Zn) although it could not be confirmed in any of these species when coefficients calculated on shoot concentration of the elements were considered.
Estimating genealogical relationships among genes at the population level presents a number of difficulties to traditional methods of phylogeny reconstruction. These traditional methods such as parsimony, neighbour-joining, and maximum-likelihood make assumptions that are invalid at the population level. In this note, we announce the availability of a new software package, TCS, to estimate genealogical relationships among sequences using the method of Templeton et al. (1992) .
Sequence data from the nuclear ribosomal internal transcribed spacer (ITS) region of 85 species (131 accessions) were used to determine the tribal limits, monophyly status, and phylogenetic intra-tribal relationships of genera within the tribe Alysseae (Brassicaceac). Both maximum parsimony and maximum likelihood analyses support the recognition of the tribe Alysseae s. str. (12 genera: Alyssoides, Alyssum. Aurinia, Berteroa, Bornmuellera, Clastopus, Clypeola, Degenia, Fibigia, Galitzkya, Hormathophylla, and Physoptychis). Six well-supported clades were recognized within the Alysseae clade, including two Alyssum clades (one of which includes Clypeola). an Alyssoides and allies clade (includes Alyssoides. Bornmuellera, Clastopus, Degenia, Fibigia, Hormathophylla, and Physoptychis), a Berteroa and allies clade (includes Aurinia, Berteroa, and Galitzkya), a Bornmuellera clade, and a Hormathophylla clade. Morphological and cytological support for these clades is reviewed. The ITS data support the exclusion of the following taxa from the Alysseae, with appropriate tribal assignment given in parentheses: Alyssum klimesii Al-Shehbaz (Camelineae), Asperuginoides (unresolved), Athysanus (Arabideae), Botschantzevia (Arabideae), Didymophysa (unresolved), Farsetia (Malcolmieae), Lobularia (Malcolmieae), and Ptilotrichum (Arabideae). Farsetia and Lobularia are inferred to be monophyletic, and based on molecular and morphological characters they are assigned to Malcolmieae, a recently described tribe.
Climatic fluctuations during Quaternary glaciations had a significant influence on the distribution of taxa and on their intraspecific genetic structure. In this paper, we test hypotheses on Pleistocene refugia for mountain plants in the eastern part of the European Alps derived from palaeoenvironmental and geological results, with new data on distributional patterns of 288 vascular plant endemics and molecular phylogeographies of selected species. High numbers of endemics are found in calcareous regions at the southern and the eastern border of the Eastern Alps, which remained unglaciated during the Pleistocene. The distribution of local endemic taxa in general, and of silicicolous taxa in particular, shows a clear relationship with hypothetical glacial refugia in the southern, southeastern, easternmost, and northeastern Alps. Molecular phylogeographic data from several silicicolous alpine species (Androsace alpina, Androsace wulfeniana, Eritrichium nanum, Phyteuma globulariifolium, Ranunculus glacialis, Saponaria pumila) are not completely congruent. However, all genetically defined population groups are in congruence with hypothetical refugia. In general, results from distributions of endemic taxa and data from intraspecific phylogeography are compatible with previously hypothesized refugia suggesting that refugial situations have shaped the current patterns. The combination of patterns of endemism with molecular phylogeographic data provides an efficacious approach to reveal glacial refugia in vascular plants.
Recent studies of the Alyssum montanum – A. repens complex in Europe showed that populations from central and southern Italy are, in contrast to previous taxonomic treatments, clearly distinct from A. montanum and should be classified as A. diffusum. Based on the high, geographically structured genetic variation (central Apennines, Gargano, and southern Apennines/Calabria) of A. diffusum, three subspecies were recently recognised. Here, we present a detailed morphometric study of A. diffusum, exploring its differentiation from A. montanum and differentiation among the three subspecies (A. diffusum subsp. diffusum, subsp. garganicum, and subsp. calabricum). We report that A. diffusum differs from A. montanum, particularly by having (on average) larger flower parts (from subsp. gmelinii) and different density and morphology of trichomes and width of petals (from subsp. montanum). The subspecies of A. diffusum can be distinguished by the number and length of trichome rays, by trichome density on the lower leaf surface, and by the leaf length. In this study, we present an identification key which includes the subspecies of A. diffusum, those of A. montanum and a related A. cuneifolium. We also provide detailed morphological descriptions of all three subspecies of A. diffusum and a nomenclatural account, including the designation of the lectotype of the name A. diffusum.
Papaver alpinum s.l. is an extraordinarily polymorphic taxon distributed throughout southern and central European mountain ranges. We tested previous hypotheses about relationships and taxonomical status of the numerous described taxa within this species or species group by applying different molecular approaches. In addition we re-evaluated morphological characters used in previous taxonomic treatments in the light of the molecular results. The ancestral sequence haplotypes were widespread and dominant throughout the Alps, whereas peripheral populations in other mountain ranges were often characterised by haplotypes directly derived from the central haplotypes involving one or two mutational steps. The AFLP data corroborated the pattern of a 'centrifugal radiation' and additionally showed that most populations were genetically distinct, presumably due to the effect of genetic drift in small and isolated populations. The morphological data did not reveal clear patterns of variation; only the Pyrenean and Sierra Nevada populations differed in two non-overlapping and presumably independent characters. Altogether, our study implies that most previous taxonomic concepts of P. alpinum s. l. were highly artificial, and that either nearly all populations have to be raised to some taxonomic rank or that, preferably, no infraspecific taxa should be recognised at all. The only segregate possibly deserving taxonomic rank, based on both morphology and genetics, is the Iberian P. alpinum subsp. lapeyrousianum.
A critical review of characters used in the systematics of the Brassicaceae is given, and aspects of the origin, classification,
and generic delimitation of the family discussed. Molecular phylogenetic studies of the family were reviewed, and major clades
identified. Based on molecular studies, especially from the ndhF chloroplast gene, and careful evaluation of morphology and generic circumscriptions, a new tribal alignment of the Brassicaceae
is proposed. In all, 25 tribes are recognized, of which seven (Aethionemeae, Boechereae, Descurainieae, Eutremeae, Halimolobeae,
Noccaeeae, and Smelowskieae) are described as new. For each tribe, the center(s) of distribution, morphology, and number of
taxa are given. Of the 338 genera currently recognized in the Brassicaceae, about 260 genera (or about 77%) were either assigned
or tentatively assigned to the 25 tribes. Some problems relating to various genera and tribes are discussed, and future research
developments are briefly covered.
The genus Alyssum is one of the largest, yet least known genera of the Brassicaceae family. The present study focusses on the Central European populations of A.montanum, a species that is highly variable with respect to its morphology, ploidy levels and ecological requirements. This variation is naturally reflected in a number of recognised infraspecific taxa, and diverse opinions exist with regards to their value and circumscriptions. Based on amplified fragment length polymorphism (AFLP), as well as morphometric and flow-cytometric evidence, we demonstrate here that the variation patterns contradict the current taxonomic concepts held for this species. Our data support the division of the analysed populations into the following groupings: (i) the ‘core’ group that includes most of the Central European diploid and tetraploid populations; (ii) the diploid ‘Swiss–SW German’ group, also including the population from the type locality of A.montanum; (iii) the hexaploid A.montanum subsp. pluscanescens, a Slovenian and Croatian endemic suggested to be of hybrid origin; and (iv) the diploid ‘Serbian’ group from the sand dunes of Deliblatska Peščara. A.repens, represented by a diploid population from Austria and tetraploid populations from Romania, is confirmed to be distinct from A.montanum. On the other hand, we suggest rejecting the recognition of A.montanum subsp. brymii, an assumed endemic of Slovakia and Hungary, and A.montanum subsp. montanum and subsp. gmelinii in their traditional circumscriptions.
Lead and zinc concentrations were determined in Thlaspi rotundifolium subsp. cepaeifolium and Alyssum wulfenianum growing on mine tailings and contaminated river gravels derived from lead-zinc mines in the Cave del Predil (Raibl) area of Northern Italy. Lead levels of up to 8200 μg g−1 (0·82%) and zinc levels of up to 17 300 μg g−1 (1·73%) were found in dried leaves of the former species. Corresponding values for A. wulfenianum were 860 and 2500 μg g−1, respectively. The lead concentrations in the Thlaspi subspecies are easily the highest ever recorded for any flowering plant. The existence of non-tolerant taxa very similar to these two metallophytes and growing on non-contaminated ground in the same general area, leads to the conclusion that colonisation of these mine wastes may be a neo-endemic process.
Flow cytometry (FCM) has been widely used in plant science to determine the amount of nuclear DNA, either in absolute units or in relative terms, as an indicator of ploidy. The requirement for fresh material in some applications, however, limits the value of FCM in field research, including plant biosystematics, ecology and population biology. Dried plant samples have proven to be a suitable alternative in some cases (large-scale ploidy screening) although tissue dehydration is often associated with a decrease in the quality of FCM analysis. The present study tested, using time-scale laboratory and in situ field experiments, the applicability of glycerol-treated nuclear suspension for DNA flow cytometry. We demonstrate that plant nuclei preserved in ice-cold buffer + glycerol solution remain intact for at least a few weeks and provide estimates of nuclear DNA content that are highly comparable and of similar quality to those obtained from fresh tissue. The protocol is compatible with both DAPI and propidium iodide staining, and allows not only the determination of ploidy level but also genome size in absolute units. Despite its higher laboriousness, glycerol-preserved nuclei apparently represent the most reliable way of sample preservation for genome size research. We assume that the protocol will provide a vital alternative to other preservation methods, especially when stringent criteria on the quality of FCM analysis are required.
Since its introduction in 2001, MrBayes has grown in popularity as a software package for Bayesian phylogenetic inference using Markov chain Monte Carlo (MCMC) methods. With this note, we announce the release of version 3.2, a major upgrade to the latest official release presented in 2003. The new version provides convergence diagnostics and allows multiple analyses to be run in parallel with convergence progress monitored on the fly. The introduction of new proposals and automatic optimization of tuning parameters has improved convergence for many problems. The new version also sports significantly faster likelihood calculations through streaming single-instruction-multiple-data extensions (SSE) and support of the BEAGLE library, allowing likelihood calculations to be delegated to graphics processing units (GPUs) on compatible hardware. Speedup factors range from around 2 with SSE code to more than 50 with BEAGLE for codon problems. Checkpointing across all models allows long runs to be completed even when an analysis is prematurely terminated. New models include relaxed clocks, dating, model averaging across time-reversible substitution models, and support for hard, negative, and partial (backbone) tree constraints. Inference of species trees from gene trees is supported by full incorporation of the Bayesian estimation of species trees (BEST) algorithms. Marginal model likelihoods for Bayes factor tests can be estimated accurately across the entire model space using the stepping stone method. The new version provides more output options than previously, including samples of ancestral states, site rates, site d(N)/d(S) rations, branch rates, and node dates. A wide range of statistics on tree parameters can also be output for visualization in FigTree and compatible software.
In order to uncover patterns and processes of segregation of co-existing cytotypes, we investigated a zone in the eastern Alps (Austria) where diploid and hexaploid individuals of the alpine herb Senecio carniolicus Willd. (Asteraceae) co-occur. Linking the fine-scale distribution of cytotypes to environmental and spatial factors revealed segregation along an ecological gradient, which was also reflected in the cytotype-associated plant assemblages. Compared to diploids, hexaploids are found in more species-rich and denser communities. This may be due to their better competitive ability and lower tolerance of abiotic stress compared to the diploids. The lack of any intermediate cytotypes suggests the presence of strong reproductive isolation mechanisms, whose nature is, however, elusive.
Motivation: To improve the estimation of evolutionary distances between nucieotide sequences by considering the differences in substitution rates among sites.
Results: TREECON for Windows (Van de Peer.Y. and De Wachter.R. Comput. Applic. Biosci., 9, 569–570, 1994) is a software package for the construction and drawing of phylogenetic trees based on distance data computed from nucleic acid and amino acid sequences. For nucleic acids, we here describe the implementation of a recently developed method for estimating evolutionary distances taking into account the substitution rate of individual sites in a sequence alignment.
Availability: TREECON for Windows is available on request from the authors. A small fee is asked in order to support the work and to reinvest in new computer hard- and software. More information about the program and substitution rate calibration can be found at URL http://bioc-www.uia.ac.be/u/yvdp/treeconw.html
Dear Ksenia,
sorry, please contact: www.xflora.info
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Manfred A. Fischer
Premise of the study:
The Apennine Peninsula, one of the three peninsulas of the European Mediterranean, is an important hotspot of genetic and species diversity, but studies devoted to plant evolution are still very scarce in this region. We studied the diploid-polyploid complex of Alyssum montanum-A. repens, focusing on Apennine and adjacent southwestern Alpine populations from southeastern France, with the aim of examining their taxonomic position and evolutionary patterns.
Methods:
We employed AFLP markers and cpDNA sequences, along with cytotype determination using flow cytometry, and a multivariate morphometric approach.
Key results:
The Italian and French populations formed two well-delimited groupings within the studied complex that were, in contrast to previous taxonomic treatments, clearly distinct from A. montanum. Populations from southeastern France represent A. orophilum, a previously described but abandoned species. Those from central and southern Italy correspond to A. diffusum, exhibiting high, geographically structured variation (central Apennines, Gargano, and southern Apennines/Calabria). This pattern coincides with hotspot refugial regions, in congruence with the "refugia-within-refugia" hypothesis, and is reflected here in the recognition of three subspecies within A. diffusum.
Conclusions:
We provide evidence for the presence of Mediterranean refugia for the studied Alyssum montanum-A. repens complex located in central and southern Italy, which, however, did not contribute to the postglacial colonization of Central Europe. Past extinctions, genetic bottlenecks, and recent expansion were inferred in Central Europe, while long-term accumulation of diversity as well as polyploidization occurred in the Apennines.
The study of yeast cell morphology requires consistent identification of cell cycle phases based on cell bud size. A computer-based image processing algorithm is designed to automatically classify microscopic images of yeast cells in a microfluidic channel environment. The images were enhanced to reduce background noise, and a robust segmentation algorithm is developed to extract geometrical features including compactness, axis ratio, and bud size. The features are then used for classification, and the accuracy of various machine-learning classifiers is compared. The linear support vector machine, distance-based classification, and k-nearest-neighbor algorithm were the classifiers used in this experiment. The performance of the system under various illumination and focusing conditions were also tested. The results suggest it is possible to automatically classify yeast cells based on their morphological characteristics with noisy and low-contrast images.
MOTIVATION: Real evolutionary data often contain a number of different and sometimes conflicting phylogenetic signals, and
thus do not always clearly support a unique tree. To address this problem, Bandelt and Dress (Adv. Math., 92, 47-05, 1992)
developed the method of split decomposition. For ideal data, this method gives rise to a tree, whereas less ideal data are
represented by a tree-like network that may indicate evidence for different and conflicting phylogenies. RESULTS: SplitsTree
is an interactive program, for analyzing and visualizing evolutionary data, that implements this approach. It also supports
a number of distances transformations, the computation of parsimony splits, spectral analysis and bootstrapping.
Chloroplast DNA sequences are a primary source of data for plant molecular systematic studies. A few key papers have provided the molecular systematics community with universal primer pairs for noncoding regions that have dominated the field, namely trnL-trnF and trnK/matK. These two regions have provided adequate information to resolve species relationships in some taxa, but often provide little resolution at low taxonomic levels. To obtain better phylogenetic resolution, sequence data from these regions are often coupled with other sequence data. Choosing an appropriate cpDNA region for phylogenetic investigation is difficult because of the scarcity of information about the tempo of evolutionary rates among different noncoding cpDNA regions. The focus of this investigation was to determine whether there is any predictable rate heterogeneity among 21 noncoding cpDNA regions identified as phylogenetically useful at low levels. To test for rate heterogeneity among the different cpDNA regions, we used three species from each of 10 groups representing eight major phylogenetic lineages of phanerogams. The results of this study clearly show that a survey using as few as three representative taxa can be predictive of the amount of phylogenetic information offered by a cpDNA region and that rate heterogeneity exists among noncoding cpDNA regions.
The latest version of ImageJ, ImageJ 1.31, has released by Wayne Rasband of the Research Services Branch, National Institute of Mental Health, Bethesada, Md. ImageJ holds a unique position because it not only is in the public domain, but also runs on any operating system. It can read most of the common and important formats used in the field of biomedical imaging. The program supports all common image manipulations, including reading and writing of image files, and operations on individual pixels, image regions, whole images and volumes. The simple ImageJ macro acquire an image every 10 seconds and stores and stores it in sequence. ImageJ has attracted a varied and dedicated group of users because it is free and expandable, and can operate on any platform.
— We studied sequence variation in 16S rDNA in 204 individuals from 37 populations of the land snail Candidula unifasciata (Poiret 1801) across the core species range in France, Switzerland, and Germany. Phylogeographic, nested clade, and coalescence analyses were used to elucidate the species evolutionary history. The study revealed the presence of two major evolutionary lineages that evolved in separate refuges in southeast France as result of previous fragmentation during the Pleistocene. Applying a recent extension of the nested clade analysis (Templeton 2001), we inferred that range expansions along river valleys in independent corridors to the north led eventually to a secondary contact zone of the major clades around the Geneva Basin. There is evidence supporting the idea that the formation of the secondary contact zone and the colonization of Germany might be postglacial events. The phylogeographic history inferred for C. unifasciata differs from general biogeographic patterns of postglacial colonization previously identified for other taxa, and it might represent a common model for species with restricted dispersal.
The phylogenetic relationships of the genus Sorghum and related genera were studied by sequencing the nuclear ribosomal DNA (rDNA) internal transcribed spacer region (ITS). DNA was extracted from 15 Sorghum accessions, including one accession from each of the sections Chaetosorghum and Heterosorghum, four accessions from Parasorghum, two accessions from Stiposorghum, and seven representatives from three species of the section Sorghum (one accession from each of S. propinquum and S. halepense, and five races of S. bicolor). The maize (Zea mays) line, H95, and an accession from Cleistachne sorghoides were also included in the study. Variable nucleotides were used to construct a strict consensus phylogenetic tree. The analyses indicate that S. propinquum, S. halepense and S. bicolor subsp. arundinaceum race aethiopicum may be the closest wild relatives of cultivated sorghum; Sorghum nitidum may be the closest 2n=10 relative to S. bicolor, the sections Chaetosorghum and Heterosorghum appear closely related to each other and more closely related to the section Sorghum than Parasorghum; and the section Parasorghum is not monophyletic. The results also indicate that the genus Sorghum is a very ancient and diverse group.
Maps of distribution of some genera of Cruciferae in Europe (e.g. Ricotia, Lunaria, Alyssum, Lobularia, Clypeola, Draba, Erophila, Cochlearia, etc.) in order to complement Flora Europaea. Information is devoted to synonyms, notes on taxonomy, nomenclature, chromosome numbers and others items.
A chemical analysis of the polyphenolic patterns of diploid and tetraploid populations of Lotus corniculatus s.l. (Fabaceae) growing in the southern French Alps showed that diploids from Mont Ventoux and from Montagne de Lure belong to the same chemotype. On the other hand, tetraploids showed two different chemotypes. This paper suggests the following hypothesis about the evolution of Lotus corniculatus in this area since the last glaciation: diploids could be derived from a relic diploid population scattered by glaciation and restricted within very narrow areas, whereas the tetraploids originating from the diiploids were more competitive and radiated into larger areas cleared from ice. Key words: Lotus corniculatus, birdsfoot trefoil, Fabaceae, polyploidy, polyphenolic metabolism, evolution.
Alyssum montanum subsp. montanum and A. montanum subsp. gmelinii have been treated as two largely sympatric taxa that occur throughout the European continent. The former was regarded to grow on calcareous and serpentine rocks and in dry grasslands, and the latter mostly on sand dunes. In this study, we demonstrate that the traditional delimitation of these two subspecies is not substantiated and should be considerably revised. Focusing on Central Europe (encompassing type localities of both above-mentioned names) and inferring from genetic (plastid DNA sequences and amplified fragment length polymorphism markers) and morphological data, we provide here a new circumscription of these two subspecies of A. montanum. The name A. montanum subsp. montanum is applicable to the populations in SW Germany, Switzerland and E France and is characterized by wider petals, denser leaf indumentum, and numerous but shorter trichome rays. Alyssum montanum subsp. gmelinii includes both diploid and tetraploid populations that are widespread in the rest of Central Europe. Habitat specificity was not confirmed by our studies. The subspecies are allopatric in Central Europe, but their overall distribution ranges in Europe need to be explored further. Genetic patterns suggest different evolutionary histories for the two subspecies. An identification key and a nomenclatural survey are also presented.
Summary • Molecular phylogeny based on ribosomal internal transcribed spacer (ITS) sequences was studied to investigate the phyletic relationships among some nickel (Ni)-hyperaccumulating and nonhyperaccumulating species of the genus Alyssum in relation to their geographic distribution and Ni-hyperaccumulating phenotype. • Thirty-seven samples belonging to 32 taxa were analysed by sequencing the polymerase chain reaction-amplified ITS region and performing neighbor joining, maximum parsimony and maximum likelihood phylogenetic analyses. • The ITS region in the sampled species varied from 221 to 307 bp of ITS1 and from 194 to 251 bp of ITS2. A total of 765 characters was used to infer the phylogeny and the average nucleotide variation detected was 15.15%. • Nickel-hyperaccumulation could have been lost or acquired independently more than once during the speciation of the genus. The geographical location of species could not be related to phylogenetic affinities.
Abramoff, M.D., Magelhaes, P.J., Ram, S.J. "Image Processing with ImageJ". Biophotonics International, volume 11, issue 7, pp. 36-42, 2004.
Missing data are commonly encountered using multilocus, fragment-based (dominant) fingerprinting methods, such as random amplified polymorphic DNA (RAPD) or amplified fragment length polymorphism (AFLP). Data sets containing missing data have been analysed by eliminating those bands or samples with missing data, assigning values to missing data or ignoring the problem. Here, we present a method that uses random assignments of band presence–absence to the missing data, implemented by the computer program famd (available from http://homepage.univie.ac.at/philipp.maria.schlueter/famd.html), for analyses based on pairwise similarity and Shannon's index. When missing values group in a data set, sample or band elimination is likely to be the most appropriate action. However, when missing values are scattered across the data set, minimum, maximum and average similarity coefficients are a simple means of visualizing the effects of missing data on tree structure. Our approach indicates the range of values that a data set containing missing data points might generate, and forces the investigator to consider the effects of missing values on data interpretation.
Aim The central aim of this paper is to localize areas of endemism of the vascular plant flora in the Eastern Alps. Moreover, causes for location and limits of the areas of endemism are assessed.
Location The study area includes the Eastern European Alps and adjacent lowland areas.
Methods Analyses were based on 288 vascular plant taxa endemic to the study region, scored in 115 operational geographic units, which were predominantly mountain ranges. For each of these units, number of endemic taxa, range down weighted endemism, environmental variables, elevation of the last glacial maximum ice sheet, and elevation of the snowline during the last glacial maximum, were estimated. To evaluate the relationships between the geographical areas, the presence/absence matrix of endemics in areas was used to calculate phenograms and cladograms. Values from the range down weighted endemism superimposed on phenograms and cladograms were used to indicate areas of endemism. Linear regressions between richness in endemism and environmental as well as palaeo-environmental variables were used to infer causes of the observed patterns of endemism.
Results The endemic taxa of the Eastern Alps show a very uneven distribution, the majority being confined to one or few mountain ranges. High levels of endemism are found in the southern, southeastern, easternmost, and northeastern Eastern Alps. Trees obtained from phenetic and cladistic methods were largely congruent. Seven areas of endemism were clearly delimited, all in regions that are regarded as glacial refugia. Two of them are located on siliceous, four on calcareous bedrock. Not all endemic taxa, however, grow in the areas of endemism. Therefore, enlargement areas are suggested. Linear regression showed a significant correlation between high endemism and low glacial ice cover, but not with other environmental variables.
Main conclusions Vicariance resulting from Pleistocene glaciations is the most important factor causing distributional patterns of endemic plants and the formation of areas of endemism. Mapping values of weighted endemism onto trees facilitated delimitation and definition of the areas of endemism. Because of their strong dependence on siliceous bedrock and the resulting disjunct distributional patterns of some taxa in the Southern Alps, the inclusion of a few operational geographic units with high levels of endemism was not supported by the analyses. Despite post-vicariant dispersal that causes problems in analyses of areas of endemism, the circumscription of areas of endemism in the Eastern Alps was possible to a satisfactory extent. Other methodological approaches, however, which include concepts of post-vicariant dispersal and that allow overlap of areas of endemism would be highly useful.
Climatic history and ecology are considered the most important factors moulding the spatial pattern of genetic diversity. With the advent of molecular markers, species’ historical fates have been widely explored. However, it has remained speculative what role ecological factors have played in shaping spatial genetic structures within species. With an unprecedented, dense large-scale sampling and genome-screening, we tested how ecological factors have influenced the spatial genetic structures in Alpine plants. Here, we show that species growing on similar substrate types, largely determined by the nature of bedrock, displayed highly congruent spatial genetic structures. As the heterogeneous and disjunctive distribution of bedrock types in the Alps, decisive for refugial survival during the ice ages, is temporally stable, concerted post-glacial migration routes emerged. Our multispecies study demonstrates the relevance of particular ecological factors in shaping genetic patterns, which should be considered when modelling species projective distributions under climate change scenarios.
Climatic oscillations in the Quaternary have played a major role in changing the geographical distribution of plant species. Recent molecular work has provided new insights into the location of glacial refugia and routes of postglacial expansion. A comparative analysis shows that phylogeographic patterns in Europe appear to be less congruent than in North America. The change of geographical distribution has also provided opportunities for speciation through isolation, and hybridization after secondary contact. However, a complete understanding of the significance of the Quaternary climatic changes for plant speciation requires further research into the estimation of reliable and accurate divergence times.