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Background and Aims The most species-rich and ecologically diverse plant radiation on the Canary Islands is the Aeonium alliance (Crassulaceae). In island radiations like this, speciation can take place either within islands or following dispersal between islands. Aiming at quantifying intra- and inter-island speciation events in the evolution of Aeonium, and exploring their consequences, we hypothesized that (1) intra-island diversification resulted in stronger ecological divergence of sister lineages, and that (2) taxa on islands with a longer history of habitation by Aeonium show stronger ecological differentiation and produce fewer natural hybrids. Methods We studied the biogeographical and ecological setting of diversification processes in Aeonium with a fully sampled and dated phylogeny inferred using a ddRADseq approach. Ancestral areas and biogeographical events were reconstructed in BioGeoBEARS. Eleven morphological characters and three habitat characteristics were taken into account to quantify the morphological and ecological divergence between sister lineages. A co-occurrence matrix of all Aeonium taxa is presented to assess the spatial separation of taxa on each island. Key Results We found intra- and inter-island diversification events in almost equal numbers. In lineages that diversified within single islands, morphological and ecological divergence was more pronounced than in lineages derived from inter-island diversification, but only the difference in morphological divergence was significant. Those islands with the longest history of habitation by Aeonium had the lowest percentages of co-occurring and hybridizing taxon pairs compared with islands where Aeonium arrived later. Conclusions Our findings illustrate the importance of both inter- and intra-island speciation, the latter of which is potentially sympatric speciation. Speciation on the same island entailed significantly higher levels of morphological divergence compared with inter-island speciation, but ecological divergence was not significantly different. Longer periods of shared island habitation resulted in the evolution of a higher degree of spatial separation and stronger reproductive barriers.

Two species of the Calcarata species complex of Viola section Melanium have been hypothesized to be of polyploid hybrid origin. To test this hypothesis, we used a modified restriction site associated (RAD) DNA-sequencing approach along with ITS and plastid DNA sequence data for reconstructing and dating the phylogeny of the group. For the detection of polyploid hybrid speciation and the parental lineages involved we used the four-taxon D-statistic metric (ABBA-BABA). Viola corsica (Elba, Corsica, Sardinia; calcifuge) and V. tineorum (Sicily; calcicole) were confirmed as polyploid hybrid species. They share V. cassinensis subsp. cassinensis (central Apennine; calcicole) as a parental lineage with V. bertolonii (Maritime Alps; serpentine) as the second parent of V. corsica and with V. nebrodensis (Sicily; calcicole) as the second parent of V. tineorum. The geographical distribution of the two hybrid species reflects the geographical distribution of the differential parent lineages. Substrate requirements of V. corsica are different, and those of V. tineorum are identical to those of their respective parents. We conclude that the differential distribution and ecology of V. corsica and V. tineorum can be traced back to properties of their respective parents.

Die Sand-Quecke, Elymus arenosus, ist eine in ihrer Umgrenzung, taxonomischen Bewertung und geographischen Verbreitung umstrittene Art. Während einige Autoren sie als Endemiten des Mainzer Sandes betrachten, wird sie von anderen Autoren, häufig als Unterart, als auch an den Küsten Nordwesteuropas weitverbreitet aufgefasst. Unter Verwendung von plastidären trnL-trnF und nukleär-ribosomalen ITS-Sequenzen wird hier versucht, die Identität, Verbreitung und mögliche Verwandtschaft von E. arenosus zu klären. Individuen vom Mainzer Sand haben einen nur ihnen eigenen trnL-trnF-Haplotypen, der auch in als E. arenosus identifiziertem Material aus den Niederlanden (Millingerwaard) gefunden wurde, sowie einige nur ihnen eigene ITS-Ribotypen. In Verbindung mit der ihr eigenen Morphologie und älteren Berichten der Art vom Oberrhein führt uns das zu dem Schluss, dass E. arenosus als Art bewertet werden sollte und ehemals entlang des Rheins weiter verbreitet war. E. arenosus hat eine Chromosomenzahl von 2n = 28. Molekulare und morphologische Ähnlichkeiten lassen es möglich erscheinen, dass E. campestris der engste Verwandte von E. arenosus ist.

Die Sand-Lotwurz, Onosma arenaria, kommt in Deutschland nur im Gebiet des Mainzer Sandes vor. Es wird allgemein angenommen, dass das Vorkommen der Art hier als Restvorkommen einer nacheiszeitlich weiter ausgedehnten, heute südosteuropäischen Steppe interpretiert werden muss. Jüngere Untersuchungen haben gezeigt, dass O. helvetica aus der südwestlichen Schweiz und dem südöstlichen Frankreich sehr eng mit O. arenaria verwandt ist und als Teil dieser Art betrachtet werden kann. Vor diesem Hintergrund wird der Frage nachgegangen, ob O. arenaria vom Mainzer Sand evtl. mit südwestlichen und nicht mit südöstlichen Populationen der Art verwandt ist. Die Analyse plastidärer rpl32-trnL- und nukleär-ribosomaler ITS-Sequenzen führte zu dem überraschenden Ergebnis, dass O. arenaria vom Mainzer Sand sowohl südöstliche als auch südwestliche ITS-Sequenztypen enthält. Damit zeigt die Population vom Mainzer Sand Beziehungen zu beiden Gebieten und kann nicht mehr als Relikt einer südöstlichen Steppe interpretiert werden. Die erstmalige Bestimmung der Chromosomenzahl und -morphologie von O. arenaria vom Mainzer Sand bestätigt Befunde aus anderen Gebieten.

This special issue of the journal Alpine Botany brings together syntheses, macroecological and taxon-specific studies of patterns and processes of plant evolution in major mountain ranges across Europe, Africa, the Americas and Asia. Apart from reflecting current conceptual and methodological perspectives in the field, it contributes to our understanding of the interplay between factors determining the evolution and distribution of plant variation across topographically complex areas, and will help to identify the components necessary for building an integrative model of the origin and distribution of diversity in mountain areas.

Ecogeographical displacement of homoploid hybrid lineages from their parents is well documented and considered an important mechanism to achieve reproductive isolation. In this study, we investigated the origin of the flowering plant species Sempervivum tectorum in the Massif Central (France) through homoploid hybridization between lineages of the species from the Rhine Gorge area (Germany) and the Pyrenees (France). We used genotyping-by-sequencing genetic data as evidence for the hybrid origin of the Massif Central lineage, and WorldClim climatic data and soil pH and soil temperature data collected by us for ecological niche and species distribution modelling. We could show that the Massif Central lineage shows hybrid admixture and that the niche of this lineage is significantly different from those of the parental lineages. In comparison with the parental niches, different variables of the niche of the hybrid lineage are intermediate, parental-combined or extreme. The different niche of the Massif Central populations thus can plausibly be interpreted as hybridization-derived. Our species distribution modelling for the Last Glacial Maximum and Mid-Holocene showed that the potential distribution of the hybrid lineage at the likely time of its origin in the Quaternary possibly was parapatric in relation to the largely sympatric distributions of the parental lineages. We hypothesize that reproductive isolation of the hybrid lineage from the parental lineages resulted from the segregation of distribution ranges by a differential response of the three lineages to a warming climate.

The distinction of the annual Sagina apetala and S. micropetala (= S. apetala subsp. erecta, S. filicaulis) is based mainly on the position of sepals in fruit and shape and colour of the sepals, but identification of the two species is difficult. A molecular phylogeny of material identified as S. apetala and S. micropetala as well as other species of the genus using two nuclear and two plastid markers showed that there exist two lineages that are sister to each other and can be unambiguously distinguished molecularly. Although many of the morphological characters used in the literature proved useful in distinguishing these two lineages, sepal indumentum is the most reliable character to discriminate between them in Germany. Whereas S. micropetala usually has glabrous sepals, the sepals of S. apetala usually are glandular-pubescent. The chromosome number of 2n = 12 for S. micropetala, here determined for the first time, is identical to that of S. apetala, supporting the close relationship between the two species. Sagina apetala and S. micropetala are sister to S. maritima, an annual species from European coasts, which may imply a coastal origin of the two species. A brief review of the possible origin of other European ruderals from coastal relatives is provided.

Floristic similarities between European and Asian mountain ranges have long been recognized, and the hypothesis that European mountain plant taxa immigrated from Asian mountain areas has been confirmed by several molecular phylogenetic analyses. Callianthemum contains ca. 14 species, of which ca. 11 are distributed in Asia and three in Europe. A molecular phylogenetic analysis of the genus using ITS and four plastid DNA sequences (matK, rpL32–trnL intergenic spacer, trnL–trnF intergenic spacer, trnV–ndhC intergenic spacer) revealed that the genus reached Europe twice, with C. coriandrifolium representing one, and C. anemonoides and C. kernerianum a second lineage. Support for C. anemonoides and C. kernerianum as sister species is weak. The crown group ages of the C. coriandrifolium lineage (median 2.2 million years) and of the C. anemonoides/C. kernerianum lineage (median 1.62 million years) are similar and place their immigration to Europe in the Quaternary. Analysis of climatic data shows that C. coriandrifolium grows in colder climate than C. anemonoides/C. kernerianum and that the climatic niches of the three European species are different considering all climatic variables analyzed.

Die Ranunculaceae sind eine der sieben Familien der Ordnung Ranunculales. Mit ca. 2500 Arten in 55 Gattungen sind sie die größte Familie der Ordnung. Da Gattungsgrenzen teilweise unklar sind, kann keine endgültige Gattungszahl angegeben werden. Die vorliegende Bearbeitung behandelt vor allem die Morphologie und Ökologie der Vertreter der Familie und enthält auch einen Schlüssel zum Bestimmen der im Gebiet verbreiteten Gattungen der Familie Ranunculaceae.

Nach der Entstehung des Lebens (s. Box 24.1) hat eine evolutionare Differenzierung der Lebewesen in drei Hauptgruppen stattgefunden, die meist als Reiche (Regnum/Regna) oder Domanen klassifiziert werden. Dies sind die Archaea, Bacteria und Eukarya. Gegenstand der Botanik und damit auch dieses Lehrbuchs sind Pflanzen sowie solche algenahnlichen photoautotrophen Organismen, die durch endocytobiotische Aufnahme von eukaryotischen Grun- oder Rotalgen entstanden sind. Diese Gruppen finden sich im Stammbaum des Lebens an unterschiedlichen Stellen (s. Abb. 24.1).

Tephroseris is generally considered a difficult genus. Based on the examination of extensive herbarium material and considering the existing literature, we recognize seven species in Europe outside Russia. These are T. palustris, T. integrifolia with subsp. integrifolia, subsp. aurantiaca, subsp. capitata, subsp. maritima, subsp. serpentini and subsp. “tundricola”, T. balbisiana, T. crispa, T. helenitis, T. longifolia and T. papposa. Phylogenetic analysis of ITS and ETS sequences showed that these species fall into three lineages. These are: (1) T. palustris, clearly related to Arctic species of the genus; (2) T. integrifolia; and (3) the remaining species. Molecular dating of the T. integrifolia lineage resulted in a crown group age of 1.76 (0.85–2.87) million years. Possible reasons for taxonomic difficulties in the genus in Europe outside Russia may include its young phylogenetic age and extensive migration and genetic admixture in the Quaternary. The decline of the genus in Europe outside Russia is documented and discussed. We consider it possible that its decline is related to rising global temperatures. Citation: Kadereit J. W., Laux P. & Dillenberger M. S. 2021: A conspectus of Tephroseris (Asteraceae: Senecioneae) in Europe outside Russia and notes on the decline of the genus. – Willdenowia 51: 271–317. Version of record first published online on 3 September 2021 ahead of inclusion in August 2021 issue.

Das Ziel der Systematik besteht darin, die enorme Vielfalt von Organismen unterschiedlichster Form und Lebensweise zu ordnen. Dies erfordert die Erkennung von Arten und deren Zusammenfassung zu systematischen Gruppen hoherer Rangstufe (Gattungen, Familien usw.). Zu den Aufgaben der Systematik gehort es auch, Arten und hohere systematische Gruppen zu beschreiben und zu benennen und in Form von Bestimmungsschlusseln Moglichkeiten fur deren Identifizierung zur Verfugung zu stellen. Seitdem bekannt ist, dass alle heute lebenden Organismen von einem gemeinsamen Vorfahren abstammen (s. Evolution, Kap. 22) ist die Systematik darum bemuht, die naturlichen Verwandtschaftsverhaltnisse zwischen Organismengruppen als einziger objektiver Grundlage der Gruppierung wiederzuspiegeln. Dem Ziel der Ordnung nach Verwandtschaft ist die Systematik gerade in den letzten Jahren dadurch betrachtlich naher gekommen, dass sich systematische Analysen immer mehr die in der DNA von Organismen enthaltene Information zunutze machen. Die systematische Interpretation dieser Information, aber auch der Information aus traditionellen Merkmalsbereichen wie z.B. der Morphologie, erfolgt heute unter Verwendung stark mathematisierter Verfahren, und die Qualitat systematischer Hypothesen kann statistischen Tests unterworfen werden.

Background Cherleria (Caryophyllaceae) is a circumboreal genus that also occurs in the high mountains of the northern hemisphere. In this study, we focus on a clade that diversified in the European High Mountains, which was identified using nuclear ribosomal (nrDNA) sequence data in a previous study. With the nrDNA data, all but one species was monophyletic, with little sequence variation within most species. Here, we use genotyping by sequencing (GBS) data to determine whether the nrDNA data showed the full picture of the evolution in the genomes of these species. Results The overall relationships found with the GBS data were congruent with those from the nrDNA study. Most of the species were still monophyletic and many of the same subclades were recovered, including a clade of three narrow endemic species from Greece and a clade of largely calcifuge species. The GBS data provided additional resolution within the two species with the best sampling, C. langii and C. laricifolia, with structure that was congruent with geography. In addition, the GBS data showed significant hybridization between several species, including species whose ranges did not currently overlap. Conclusions The hybridization led us to hypothesize that lineages came in contact on the Balkan Peninsula after they diverged, even when those lineages are no longer present on the Balkan Peninsula. Hybridization may also have helped lineages expand their niches to colonize new substrates and different areas. Not only do genome-wide data provide increased phylogenetic resolution of difficult nodes, they also give evidence for a more complex evolutionary history than what can be depicted by a simple, branching phylogeny.

Quaternary climatic oscillations have been a major factor in shaping plant diversity and distribution in the European Alpine System (EAS). Plants responded to these oscillations with repeated changes in their abundance and geographical distribution. However, oscillating shifts in geographical distribution have only rarely been reported in molecular analyses of genetic variation across the EAS. Homogyne, a genus endemic to the EAS, contains three species. While H. discolor and H. sylvestris are confined to the periphery of the Eastern Alps, H. alpina is widespread across the EAS. In phylogenetic reconstructions of a broad sample of Homogyne using DNA sequence data sets of the nuclear ribosomal internal transcribed spacer (ITS), plastid DNA (ndhF-rpl32, rpl32-trnL, psbA-trnH) and genotyping-by-sequencing (GBS), accessions of H. alpina from the Pyrenees and the Cantabrian Mts. form a clade which groups in conflicting positions. While the exact relationship of this Pyrenean/Cantabrian clade of H. alpina remains unclear, our data clearly imply that this clade is a lineage distinct from the remaining accessions of H. alpina (H. alpina s.str.). An ancestral area analysis unambiguously revealed the Eastern Alps as the ancestral area of the genus. Considering that relationships within H. alpina s.str. clearly illustrate East to West expansion, the identification of a Pyrenean/Cantabrian clade implies that westward expansion from an ancestral area in the Eastern Alps took place twice in the genus. Although the extant distributions of the Pyrenean/Cantabrian clade and H. alpina s.str. are mutually exclusive, plastid DNA evidence may imply past contact and hybridization between the two clades.

Understanding the relative importance of different mechanisms of speciation in a given lineage requires fully resolved interspecific relationships. Using Facchinia, a genus of seven species centred in the European Alps, we explore whether the polytomy found by Sanger sequencing analyses of standard nuclear (ITS) and plastid markers (trnQ-rps16) is a hard or soft polytomy by substantially increasing the amount of DNA sequence data, generated by genotyping-by-sequencing. In comparison to 142 phylogenetically informative sites in the Sanger sequences the GBS sequences yielded 3363 phylogenetically informative sites after exclusion of apparently oversaturated SNPs. Maximum parsimony, maximum likelihood, NeighborNet, SVDquartets and Astral-II analyses all resulted in phylogenetic trees (and networks) in which interspecific relationships were largely unresolved. After excluding incomplete lineage sorting, hybridisation and oversaturation of characters as possible causes for lack of phylogenetic resolution, we conclude that the polytomy obtained most likely represents a hard polytomy. We hypothesize that diversification of Facchinia is best interpreted as the result of multiple simultaneous vicariance in response to climatic changes during the Early Quaternary.

Cherleria sedoides, a plant species widespread in alpine areas of the major European mountain ranges and in Scotland, contains two highly divergent chloroplast haplotype groups, one widespread (WH) and one present only in some populations in the Alps (AH). We investigated whether this haplotype diversity is the result of (1) intraspecific differentiation, (2) retention of an ancestral polymorphism or (3) hybridisation. For this purpose, 106 matK sequences from throughout the Caryophyllaceae and 80 trnQ-rps16 and psbD-trnT sequences of C. sedoides (51) and other species of Cherleria (29) were used for the construction of phylogenies and haplotype networks. As the two haplotype groups were never each other’s closest relatives, haplotype diversity as a result of intraspecific differentiation is unlikely. Patterns of genetic differentiation within the WH and AH groups are very different. Whereas WH shows a radial pattern typical of rapid expansion, AH is divided into two divergent subgroups each containing more variation than the WH group. This suggests that the two haplotype groups have dissimilar histories and are therefore unlikely to represent an ancestral polymorphism. Instead, we conclude that the polymorphism is best interpreted as the result of hybridisation. As the WH and AH haplotype groups fall into Cherleria, but do not group with any extant species, we conclude that the rare AH group represents the original C. sedoides, and that the WH group was captured from another, now extinct, species of Cherleria.

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.

Summary The currently favoured model of the evolution of C4 photosynthesis relies heavily on the interpretation of the broad phenotypic range of naturally growing C3–C4 intermediates as proxies for evolutionary intermediate steps. On the other hand, C3–C4 intermediates had earlier been interpreted as hybrids or hybrid derivates. By first comparing experimentally generated with naturally growing C3–C4 intermediates, and second summarising either direct or circumstantial evidence for hybridisation in lineages comprising C3, C4 and C3–C4 intermediates, we conclude that a possible hybrid origin of C3–C4 intermediates deserves careful examination. While we acknowledge that the current model of C4 photosynthesis evolution is clearly the best available, C3–C4 intermediates of hybrid origin, if existing, should not be used for further analysis of this model. However, experimental C3 × C4 hybrids potentially are excellent systems to analyse the genetic differences between C3 and C4 species and, also using segregating progeny, to study the relationship between individual photosynthetic traits and environmental factors.

Aim Investigation of the geographical origin of Senecio and the colonization of the Palaearctic including the relationship of life-history strategy and elevational distribution in the source area and the colonized area. Location Worldwide with a focus on the Afrotropic and the Palaearctic. Methods Sampling focused on adding species from the Afrotropic to existing datasets of Senecio. Two nuclear markers and three chloroplast markers were amplified and sequenced. Maximum likelihood and Bayesian inference were used to infer phylogeny, divergence times, biogeographical history and life-history strategy evolution. Results Senecio originated most likely during the Mid to Late Miocene in western southern Africa (WSA). Colonization of the Palaearctic probably started from two different areas. One lineage of mostly annual lowland species seems to have originated in WSA, whereas the other lineage of perennial mountain species originated in mountainous areas of eastern southern Africa or tropical/subtropical East Africa. Main conclusions Senecio evolved in arid or semi-arid regions in WSA during a period of ongoing aridification and broad-scale biome changes at the onset of a winter rainfall regime in the Greater Cape Floristic Region. Life-history strategy and elevational distribution of the two Palaearctic lineages did not change between the source areas and the colonized areas.

Fossil evidence, phylogeographic analyses, species distribution modelling and ancient DNA analyses have all shown that plant distributions have been highly dynamic through time. We use the geographical distribution of intra- and interspecific hybrids in Sempervivum, a western Eurasian high mountain oreophyte, as evidence for the past range dynamics of their parents. Sequences of the nuclear ribosomal internal transcribed spacer (ITS), parts of the nuclear ribosomal intergenic spacer region (IGS), and the three chloroplast markers atpI–atpH, rps16-intron and trnQ–rps16 were generated for 101 individuals of Sempervivum from across its entire distribution range. Hybrid individuals were identified by the presence of double base calls in direct sequencing of polymerase chain reaction products of ITS and IGS. Parentage was inferred from comparison with sequences without double base calls and with cpDNA sequences. We identified 27 hybrid individuals, which were found outside the current distribution range of one parent in 10 cases and with both (or all three) parents in eight cases. Geographical distance of hybrids and allopatric parents ranged from 25 to 2100 km. The distribution of hybrid individuals in relation to their parents provides evidence for past range dynamics and migration over sometimes large geographical distances. As all taxa involved had been postulated to be of Quaternary origin in an earlier study, we hypothesise that hybridisation took place in glacial refugia where the parental species came into contact.

Decreasing plant size with increasing latitude or altitude is a commonly observed pattern. Among the four genera of the Petasites-clade (Asteraceae–Senecioneae), Petasites and Tussilago, widespread throughout the Northern Hemisphere, mostly have large leaves and many capitula, whereas Homogyne and Endocellion from alpine and arctic environments have much smaller leaves and only one or few capitula. We present a comprehensively sampled and dated phylogeny of Petasites, Endocellion, Homogyne and Tussilago based on nuclear ribosomal ITS and plastid ndhF-rpl32 and rpl32-trnL sequences. The four genera form a well-supported monophyletic group. Endocellion was found to be nested in Petasites, and relationships among the other three genera remain unresolved. Dwarfism with small leaves and a reduced number of capitula evolved five times in arctic–alpine species of this group. Although all dwarf species of the Petasites-clade grow in arctic or alpine habitats, not all species from such habitats are dwarfs. In the European Alps, Homogyne alpina, H. discolor and Petasites paradoxus occur in (sub-)alpine habitats, but only the species of Homogyne are dwarfs with small leaves and only one flowering head, whereas P. paradoxus has much larger leaves and numerous capitula. These species differ in ecology: whereas Homogyne is found in nutrient-poor and stable habitats, P. paradoxus grows in nutrient-rich and often disturbed habitats. We conclude that although decreasing plant size with increasing latitude or altitude is an overall trend in the group, factors such as nutrient availability and/or habitat disturbance can counteract this trend.

Physiological drought response was evaluated for two olive cultivars commonly grown under rain fed conditions (‘Souri’ and ‘Picual’) and another selected for intensive, irrigated cultivation (‘Barnea’). ‘Souri’ is a traditional local Israeli cultivar, ‘Picual’ originated in Spain and ‘Barnea’ is a modern Israeli cultivar. Trees in pots were alternatively provided well irrigated conditions (100% FC, field capacity) or allowed to dry, first to 33% FC and then to 10% FC. Under conditions of greatest water availability, the ‘Barnea’ cultivar had the highest stomatal conductance and net photosynthesis, significantly higher than that found in ‘Souri’. Stomatal conductance and leaf water potential of ‘Souri’ and ‘Picual’ at 33% FC were not affected relative to the well irrigated treatment but decreased significantly at 10% FC. Photosynthetic parameters of ‘Souri' and ‘Picual’ were not affected by water stress. Stem growth was also not affected by drought in ‘Souri’ but was reduced at 10% FC in ‘Picual’. In contrast, the ‘Barnea’ showed higher sensitivity to low water availability with stomatal conductance and net photosynthesis reduced at 33% FC and sharp decreases in these and leaf water potential occurring at 10% FC. At 10% FC ‘Barnea’ trees showed stem shrinkage, a phenomenon not observed in the other cultivars. These results suggest a tradeoff between selection for suitability in intensively irrigated orchards and tolerance to drought.

We investigated the species composition of Saxifraga sect. Saxifraga subsect. Arachnoideae, a recently recognized taxon, using DNA sequence data (ITS, trnL–trnF, rpl32–trnL(uag)). We conclude that the subsection contains 12 species, i.e. S. aphylla, S. arachnoidea, S. berica, S. facchinii, S. hohenwartii, S. muscoides, S. paradoxa, S. petraea, S. prenja, S. presolanensis, S. sedoides and S. tenella. Of these, we provide the first molecular evidence for the membership of S. muscoides and S. prenja in S. subsect. Arachnoideae. We provide an extended morphological characterization of the subsection and an identification key to its species.Citation: Gerschwitz-Eidt M. A. & Kadereit J. W. 2020: Species composition of Saxifraga sect. Saxifraga subsect. Arachnoideae (Saxifragaceae) based on DNA sequence evidence. – Willdenowia 50: 225–233. doi: https://doi.org/10.3372/wi.50.50208Version of record first published online on 26 May 2020 ahead of inclusion in August 2020 issue.

The Calcarata species complex in Viola sect. Melanium (Violaceae) is a group of species from Italy and neighbouring islands. The complex is of considerable evolutionary interest because several hypotheses about hybrid speciation within the group have been previously proposed. Because the Calcarata complex is not well characterized morphologically, we used 142 samples representing 92 (of c. 120) species of V. sect. Melanium plus three outgroup species. Nuclear ITS and ETS and plastid trnS–trnG intergenic spacer sequences were analysed to test the monophyly of the Calcarata complex and to infer relationships among the constituent species. Both nuclear and plastid sequences resulted in very limited phylogenetic resolution. Based on the nuclear dataset, most species of the Calcarata complex were recovered in four clades that also contained species not previously associated with the complex. Results from the plastid dataset recovered most species of the complex in a large polytomy. However, one larger clade containing only Calcarata complex species could be recovered, and species of all four nuclear clades were part of this larger plastid clade. The Calcarata complex clearly could not be resolved as monophyletic. We hypothesize that the lack of phylogenetic resolution may result mainly from frequent hybridization and hybrid speciation, processes that are well documented for Viola and V. sect. Melanium.

Molecular phylogenetic results had shown that Tephroseris, a genus differentiated from its closest relatives by its pinnately veined leaves, also contains species with palmate leaf venation. This had led to the conclusion that leaf venation is a homoplasious character in the lineage containing Tephroseris. We here take a closer look at leaf venation in Tephroseris and other species of Asteraceae–Senecioneae. We found that leaf venation in Tephroseris is distinct from leaf venation in Jacobaea vulgaris and Senecio vulgaris, which both have pinnately veined leaves as typical for most species of their respective genera, and that description of the leaves of Tephroseris as pinnately veined is incorrect. Instead, leaf venation in Tephroseris is very similar to that of upper cauline leaves of Ligularia stenocephala, a species with clearly palmately veined basal and lower cauline leaves. Both L. stenocephala and Tephroseris are part of the Ligularia–Cremanthodium–Parasenecio (L–C–P) complex. We conclude that leaf venation in Tephroseris is best regarded as derived from palmate leaf venation found in the large majority of species in the L–C–P complex, and presents no morphological obstacle to the circumscription of the genus.Citation: Kadereit J. W. & Bohley K. 2020: A note on leaf venation and the circumscription of Tephroseris (Asteraceae–Senecioneae). – Willdenowia 50: 113–117. https://doi.org/10.3372/wi.50.50111Version of record first published online on 23 March 2020 ahead of inclusion in April 2020 issue.

Tertiary relict plant species of Europe have had a large distribution range before the Pleistocene but today are confined to small refugial areas. Syringa josikaea of the largely East Asian genus Syringa is a shrub of temperate forests in the Carpathians, restricted to altogether 25 small populations in two disjunct areas, the Apuseni Mountains (Romania) and the Ukrainian Carpathians. Miocene and Pleistocene fossil remains indicate the long-term presence of the species in Central Europe; hence S. josikaea has been considered a Tertiary relict. We aimed at clarifying the historical biogeography of S. josikaea by estimating the divergence time between S. josikaea and its Asian relatives, and by analysing intraspecific variation using multiple DNA sequences as well as microsatellites. The estimated divergence time between S. josikaea and its closest relatives based on nuclear ribosomal DNA sequences is 1.88 Mya [0.30–4.04 Mya highest posterior density], suggesting a relatively recent disruption of a formerly continuous distribution area. This time corresponds to the period of Early Pleistocene extinctions, when many Tertiary plant taxa went extinct in Europe. Sequence variation was found to be very low within S. josikaea. Complete identity among all samples in cpDNA may imply a bottleneck. Four different ribotypes found showed no geographic differentiation between the Apuseni Mountains and the Ukrainian Carpathians, and differentiation between these two areas was weak when considering microsatellite variation. Together these observations may imply that the extant disjunct distribution of the species arose only recently, either through colonization from one glacial refugial area or from disruption of one such area. © 2015 The Linnean Society of London, Biological Journal of the Linnean Society, 2015, ●●, ●●–●●.

A species-level phylogeny is presented for Triglochin, the largest genus of Juncaginaceae (Alismatales) comprising about 30 species of annual and perennial herbs. Triglochin has an almost cosmopolitan distribution with Australia as centre of species diversity. Trans-Atlantic and trans-African disjunctions exist in the genus. Phylogenetic analyses were conducted based on molecular data obtained from nuclear (ITS, internal transcribed spacer) and chloroplast sequence data (psbA-trnH spacer, matK gene). Based on the phylogeny of the group divergence times were estimated and ancestral distribution areas reconstructed. Our data confirm the monophyly of Triglochin and resolve relationships between the major lineages of the genus. The sister group relationship between the Mediterranean/African T. bulbosa complex and the American T. scilloides (formerly Lilaea s.) is strongly supported. This clade is sister to the rest of the genus which contains two main clades. In the first, the widespread T. striata is sister to a clade comprising annual Triglochin species from Australia. The second clade comprises T. palustris as sister to the T. maritima complex, of which the latter is further divided into a Eurasian and an American subclade. Taxonomic diversity in some clades appears to be linked to habitat shifts and is not present in old but ecologically invariable lineages such as the non-monophyletic T. maritima. Diversification in Triglochin began in the Miocene or Oligocene, and most disjunctions in Triglochin were dated to the Miocene.

The present volume of this book series completes the treatment of the Asterids. Asterids are now contained in Vols. VI (Cornales, Ericales, 2004), VII (Lamiales, 2004), VIII (Asterales, 2007), XIV (Aquifoliales, Boraginales, Bruniales, Dipsacales, Escalloniales, Garryales, Paracryphiales, Solanales, Icacinaceae, Metteniusaceae, Vahliaceae, 2016) and the present volume, which contains the orders Apiales and Gentianales (except Rubiaceae). The only families of Asterids not treated in the series are Acanthaceae (Lamiales), Convolvulaceae (Solanales) and Rubiaceae (Gentianales).

Premise of research. We reconstructed the phylogeny, biogeographical history, and evolution of edaphic association in Sempervivum and Jovibarba (Crassulaceae), two oreophytic genera of the mountain flora of Europe and adjacent areas.Methodology. Using two nuclear markers (internal transcribed spacer and parts of intergenic spacer) and three chloroplast DNA markers (atpI-atpH, rps16-intron, trnQ-rps16) for 44 of the 48 species recognized in the two genera, we obtained a molecular phylogenetic hypothesis on relationships between and within the two genera. This phylogeny was dated and used for the reconstruction of ancestral distribution areas and the evolution of edaphic association.Pivotal results. Our analyses showed that Sempervivum and Jovibarba are monophyletic sister genera. Several well-supported intrageneric clades were recovered in our nuclear phylogeny, which generally were not supported by our chloroplast data. This incongruence most likely results from hybridization. The split between the two ge...

The opportunity for habitat shift in sympatry is thought to be an important factor in sympatric speciation by facilitating assortative mating and offering opportunities for divergent selection. Oenanthe conioides (Apiaceae) is a narrow endemic from the lower Elbe river area (Germany) where it is restricted to areas experiencing fresh water tides inundating the plants twice a day. The species was shown to have originated from Oe. aquatica which is widely distributed in Europe and grows in still or slowly flowing fresh water. Reciprocal transplant experiments have previously shown that in both habitats the non-native species is less fit than the native, and several phenotypic traits have been linked to this difference in fitness. We performed an amplified fragment length polymorphism genome scan with 333 polymorphic markers searching for candidate markers for divergent selection. A relatively small fraction (2.1%) of the markers was identified as divergence outliers which fits theoretical expectations for speciation with gene flow. Some of the markers that were potentially under divergent selection showed evidence of being clustered in the genome. This suggests that there may have been a role for mechanisms that reduce breaking-up of trait complexes in the speciation process. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 113, 50–56.

The European endemic Soldanella has traditionally been divided into two morphologically well-defined sections. Section Tubiflores contains two species growing in high-elevation habitats, whereas most of the 14 species of section Soldanella inhabit montane forests. Section Tubiflores has a reduced floral morphology compared with section Soldanella. A previous phylogenetic study based on internal transcribed spacer (ITS) and AFLP data has revealed that, although the genus Soldanella itself is monophyletic, both sections are paraphyletic. Soldanella alpina (section Soldanella) forms a clade with S. minima and S. pusilla (section Tubiflores), and the grouping of S. alpina with S. pusilla has been hypothesized to be the result of hybridization between S. pusilla and an unidentified species of section Soldanella. We re-examined the phylogenetic relationships among the above species using additional sequence data (plastid DNA) and increasing the sample for ITS and AFLP data. Our new data confirmed that S. alpina is most closely related to S. pusilla. However, our data do not provide any evidence in support of the hypothesis that S. alpina is a hybrid species. In consequence, we consider it likely that the two species of section Tubiflores originated independently. The reduced floral morphology of these two alpine species is probably evidence for increased levels of self-pollination, ensuring reproductive success in a high-altitude habitat. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 175, 409–422.