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Golden everlasting paper daisies (Xerochrysum , Gnaphalieae, Asteraceae) were some of the earliest Australian native plants to be cultivated in Europe. Reputedly a favourite of Napoléon Bonaparte and Empress Joséphine, X. bracteatum is thought to have been introduced to the island of St Helena in the South Atlantic during Napoléon's exile there. Colourful cultivars were developed in the 1850s, and there is a widely held view that these were produced by crossing Xerochrysum with African or Asian Helichrysum spp. Recent molecular phylogenetic analyses and subtribal classification of Gnaphalieae cast doubt on this idea. Using single-nucleotide polymorphism (SNP) data, we looked for evidence of gene flow between modern cultivars, naturalized paper daisies from St Helena and four Xerochrysum spp. recorded in Europe in the 1800s. There was strong support for gene flow between cultivars and X. macranthum. Paper daisies from St Helena were genotypically congruent with X. bracteatum and showed no indications of ancestry from other species or from the cultivars, consistent with the continuous occurrence of naturalized paper daisies introduced by Joséphine and Napoléon. We also present new evidence for the origin of colourful Xerochrysum cultivars and hybridization of congeners in Europe from Australian collections. [ABSTRACT FROM AUTHOR]

This paper aims to shed light on distribution patterns and the relationship between species diversity and environmental heterogeneity of 17 Edraianthus taxa. We examined present and past distributions (Last Glacial Maximum) by applying ecological niche modelling. The environmental space occupied by the taxa was analysed using niche comparison methods. The results support the idea that the central and southern Dinaric Alps represent a centre of diversity and endemism in the western Balkan Peninsula. Diversity in Edraianthus is best explained by topographic (slope) and bioclimatic predictors (maximum temperature of warmest month, precipitation seasonality, precipitation of warmest quarter, precipitation of coldest quarter), suggesting that mountain areas with the most diversified relief have higher diversity. Niche modelling results suggest considerable range dynamics during the climatically unstable Quaternary. Thermophilic and lowland taxa responded with longitudinal shifts to ecologically suitable areas farther south, whereas high-mountain taxa responded mainly with elevational shifts. The greatest niche similarity is found among phylogenetically closely related taxa and among ecologically similar and often sympatric taxa. The least similarity was observed in species with marked differences in habitat elevation and in more geographically isolated species. Our results suggest that the extent of range and niche overlap varied among some taxa throughout their evolutionary history, which may have led to diversification at both allopatric and sympatric levels. The correlation between the genetic diversity of the most widespread taxon and the richness of taxa could be a consequence of past and present contacts. On the other hand, alternate periods of isolation may have favoured the emergence of taxa that are reproductively isolated and ecologically specialized. [ABSTRACT FROM AUTHOR]

Syzygium is a large genus (1200–1500 species) of Old World tropical trees, currently divided into five subgenera containing widely different numbers of species. Syzygium subgenus Perikion was defined by the presence of fibre bundles in the hypanthium wall, although until now this feature has not been investigated or images published. Furthermore, discovery of fibre bundles in certain species outside Syzygium subgenus Perikion calls for reassessment of the subgenus. In this paper, a morphological analysis is presented for all species previously associated with Syzygium subgenus Perikion or known to have fibre bundles. Results indicate the need for description of a new subgenus, Syzygium subgenus Oborapi , characterized by a distinctly goblet-shaped calyx, presence of fibre bundles in the hypanthium/mesocarp, prominent black lenticels on the abaxial leaf surface, ascending ovule orientation and species diversity centred on the Sunda Shelf. Fibre bundles are photographed and documented for the first time from a range of species and at different magnifications. A preliminary list of species is presented for Syzygium subgenus Perikion and Syzygium subgenus Oborapi , with recommendations for further investigation. [ABSTRACT FROM AUTHOR]

The paper deals with the seed morphology and anatomy of 32 wild Indian Musaceae by using light microscopy (LM) and scanning electron microscopy (SEM). This is the first comprehensive investigation into the seed micro-morphological and anatomical aspects of two genera of the family. Seed characters including shape, size, surface sculpturing (LM and SEM), seed coat thickness, layer characters and chalazal chamber column were considered. Seed characters play a significant role in the delimitation of taxa as they are more stable than vegetative (anatomical) and pollen features. Four types of seeds (oblate, ovoid, sub-globose and ellipsoid) were observed in the family, oblate seeds being the most common. LM revealed that most of the seeds have verrucate surface sculpturing, but some are smooth-verrucate or smooth. Seed size also plays an important role in the identification of the taxa to some extent. Number of layers and seed coat thickness are directly proportional to seed size. However, the thickness of endotesta, tegmen and inner endosperm layers (aleurone layers) differ in small and large seeds. The present study revealed eight types of outer sculpturing and three inner sculpturing patterns with diverse nature of anticlinal and periclinal cell walls. Based on the seed characters, a phenetic analysis was also carried out. [ABSTRACT FROM AUTHOR]

This paper aims to integrate cytogenetic and ecological approaches into a phylogenetic framework to better understand the evolution and systematics of Senna series Aphyllae , an endemic group of arid and semi-arid regions of South America. We counted the chromosome numbers at the population level in three species of series Aphyllae using a conventional technique (GIEMSA) and in situ hybridization (FISH). Phylogenetic reconstructions and inference of chromosome evolution were based on four plastid DNA regions and one nuclear marker. A principal component analysis was carried out using environmental data. Finally, ecological niche models (ENM) were implemented: (1) to identify the abiotic factors that constraint the potential geographical distribution of series Aphyllae and (2) to understand the ecological drivers for species diversification. The basic chromosome number is x = 12. Senna aphylla showed three cytotypes with (2 n = 24, 48 and 60) and S. pachyrrhiza has two cytotypes (2 n = 24 and 48). Senna crassiramea appeared to be polyploid with 2 n = 48. In diploid S. pachyrrhiza , two 45S and three 5S rDNA sites were reported. In tetraploid S. crassiramea , four 45S and four 5S rDNA sites were detected. The ENM and ecological speciation tests suggest that in series Aphyllae speciation was sometimes associated with conservatism and sometimes with niche divergence. Our results contribute to the evolutionary knowledge of Neotropical legumes and understanding of drivers of diversification in arid regions in South America. [ABSTRACT FROM AUTHOR]

Mapanoioideae are one of two subfamilies of Cyperaceae and consist of 186 species. Molecular phylogenetic relationships in subfamily Cyperoideae have recently been studied well, whereas evolutionary relationships in Mapanioideae remain little known. Subfamily Mapanioideae include two tribes. This study focuses on Hypolytreae, which is represented by three genera in Africa (Hypolytrum , Mapania and Principina). In this paper, we present the first molecular phylogenetic study of African Hypolytreae using a Sanger sequencing approach. We aim to (1) test whether Hypolytrum , Mapania and Principina are reciprocally monophyletic; (2) investigate whether the morphologically based sections in Hypolytrum and Mapania represent monophyletic taxa; (3) resolve species delimitation where multiple accessions could be sequenced and (4) explore the relationships of species occurring in West Tropical Africa vs. Central Africa. Our phylogenetic analyses strongly support Mapania and Hypolytrum as separate genera, but Principina is nested in Hypolytrum. This result is consistent with morphological differences. Mapania spp. are obligate rainforest species, but our results show that species from West Tropical Africa and species from Central Africa do not form separate clades. Dispersal between these regions may have happened during interglacial periods when the rainforest was continuous. [ABSTRACT FROM AUTHOR]

Asteraceae, the daisy family, are one of the most diverse families of angiosperms and are predominant in many ecosystems, including grasslands, deserts, savannas and high-elevation mountains. They are characterized by a peculiar inflorescence, the capitulum, which mimics a flower, but is actually made up of many tightly grouped florets. The capitulum is considered a key character underpinning the impressive evolutionary success of the family, and it plays a pivotal role in the economic importance of the family, given that many species are cultivated for their capitulum for agricultural and horticultural purposes. However, to date, there is still no comprehensive understanding of the extent of the morphological diversity of capitula across lineages of Asteraceae. This is mainly due to a lack of appropriate tools for describing such a complex and condensed structure. To address the problem, we present a protocol for characterizing the full diversity of capitula from any lineage of Asteraceae. This involves making a whole dissection of a capitulum from fresh material; it is simple and cost-effective and requires relatively easy-to-transport equipment meaning that it can be done during fieldwork. [ABSTRACT FROM AUTHOR]

Apomictic plants mostly occur at higher latitudes and higher elevations, where they tend to occupy deglaciated areas. By analysing samples of the alpine floras of different latitudinal zones of the Americas (Argentina, Bolivia, Ecuador, USA), we investigated whether the proportion of gametophytic apomixis is comparable between the temperate alpine zones of the Northern Hemisphere and the Southern Hemisphere and whether the proportion of apomictic species increases from the alpine tropics towards the temperate alpine zone. The reproductive systems of 196 species and 275 individuals were determined by a flow-cytometric seed screening of 999 seeds. Phylogenetic logistic regression was used to evaluate differences in the proportion of apomictic species in samples of regional alpine floras. The apomictic embryo:endosperm ratio was determined for 33 species (two pseudogamous species and 31 species with autonomous apomixis) belonging to 28 genera of 13 families. The probability of a species being apomictic did not significantly differ between the regions. The highest probability of a species being apomictic was estimated for the northern temperate zone (29.6%), followed by the tropical zone (12.5%), and the southern temperate zone (11.9%). Our results show that asexual plant reproduction by apomixis is not restricted to the alpine zone of the Northern Hemisphere and its representation in alpine floras of the Southern Hemisphere, including the alpine tropics, has been substantially underestimated. [ABSTRACT FROM AUTHOR]

Carex vulpina and C. otrubae are closely related and morphologically similar species that hybridize with C. remota. The spontaneous appearance of hybrids can cause difficulties in the taxonomic treatment of this group. Morphological separation of the examined species and hybrids had been tested using discriminant function analysis (DFA). We have also analysed the effect of DNA barcoding on hybrid identification from the perspective of machine learning approach (MLA). Hybrids were investigated in terms of three barcodes sequence (ITS , matK , rbcL) by means of the BLOG and WEKA (MLA). Our results provide the first insights into the morphological and genetic relationships between the studied species and their hybrids. Morphological analysis showed traits useful in the identification of hybrids, i.e. dark brown usually fibrous basal sheaths and a dorsally split beak in Carex remota  ×  C. vulpina (inherited from C. vulpina), distinctly separated spikes, and a long bract in C. otrubae  ×  C. remota (inherited from C. remota). Phylogenetic analysis also indicated a close relationship of Carex remota  ×  C. vulpina with C. vulpina and C. otrubae  ×  C. remota with C. remota. Moreover, we have presented here nomenclatural notes on the hybrids and typified the names Carex × crepinii [ C. otrubae  ×  C. remota ] and Carex × kernii [ Carex remota  ×  C. vulpina ]. [ABSTRACT FROM AUTHOR]

Erica comprises ~860 species of evergreen shrubs and trees ranged from Europe to southern Africa and Madagascar. Wood structure of the around 20 European species is well studied, but despite its relevance to adaptation across the wider geographic range, it has not yet been explored across the much greater diversity, particularly of southern African lineages. In this study, we examine wood structure of 28 Erica species from southern Africa. In the African Erica clade, loss of scalariform perforation plates could be driven by increased aridity and seasonality in the mid-Miocene, and its re-gain can represent an adaptation to freezing in the high elevation species E. nubigena. As vessels in Erica are mostly solitary, imperforate tracheary elements probably form a subsidiary conduit network instead of vessel groups. Increase of ray frequency in habitats with a prominent dry and hot season probably facilitates refilling of vessels after embolism caused by water stress. Wider rays are ancestral for the lineage comprising African Erica and the Mediterranean E. australis. The negative correlation between ray width and expression of summer drought is consistent with Ojeda's model explaining the diversification of seeders and resprouters among southern African Erica. [ABSTRACT FROM AUTHOR]

Increasing urban expansion has resulted in the decline of many natural and seminatural communities globally. However, the connectivity and genetic structure of species that survive in these urban landscapes have received little attention, especially with regard to epiphytic plants. This study aimed to describe and evaluate the connectivity and genetic structure of populations of Tillandsia recurvata , a highly abundant and widely distributed atmospheric epiphyte, amongst urban green spaces within a city. A total of 288 T. recurvata individuals were sampled across 65 trees throughout the city of Alfenas in South-East Brazil. We designed seven novel microsatellite markers and used four cross-amplified loci to determine the basic genetic structure of T. recurvata. All populations showed high global spatial genetic structure, which indicated low connectivity between urban populations. The findings of this study, as well as evidence from previous assessments of T. recurvata genetic structure, suggest that the combined effects of genetic drift, breeding system, and dispersal may have dictated the connectivity of these urban populations. This study represents an important step towards understanding epiphyte population structure within urban landscapes. Low connectivity across urban landscapes is likely to benefit epiphytes such as T. recurvata , due to their adaptability and high tolerance; this suggests a bleak future for many other more sensitive epiphytic species under predicted urbanization globally. [ABSTRACT FROM AUTHOR]

The Podocarpaceae are a morphologically diverse conifer family that have a cryptic fossil record reported since the Permian. We reviewed the fossil record of Podocarpaceae, tested the affinities of its oldest records using phylogenetic analyses, compiled macrofossil occurrence records, and investigated the diversity, distribution, and morphology of Podocarpaceae through time. We found that Permian, Triassic, and some Jurassic fossils referred to Podocarpaceae should not be placed in the family. Our total-evidence phylogenetic analyses, which sampled all major conifer lineages, recovered the Triassic Rissikia and the Jurassic Nothodacrium as stem-group conifers and the Jurassic Mataia as part of the Araucariales stem group. We further discuss the phylogenetic position of the Mesozoic enigmatic conifers Pararaucaria (Cheirolepidiaceae) and Telemachus (Voltziales), which were recovered most frequently in the conifer stem group. We conclude that the earliest reliable Podocarpaceae occurrences are from the Jurassic of both hemispheres and have scale-like leaves. Most extant genera appear in the fossil record between the Late Cretaceous and the Early Cenozoic. Many extant leaf morphologies appear in the Early Cretaceous, coeval with angiosperm diversification, consistent with the hypothesis that expanded leaves in Podocarpaceae are adaptive responses for light harvesting in angiosperm-dominated environments today. [ABSTRACT FROM AUTHOR]

It is thought that arborescent lycopsid cambial expansion kept pace with radial wood growth via tangential broadening of the fusiform initials, resulting in progressive outward expansion in tracheid diameters and an absence of de novo tracheid files. This pattern appears in distal lycopsid axes but has not been investigated in proximal-most trunk vasculature where wood was thickest and primary xylem thinnest. Here, a ground-level trunk vasculature fossil of Sigillaria approximata in transverse section is described. This proximal vasculature diverges from the expectations of the current lycopsid wood production model in two main ways: first, inner and outer wood tracheids have approximately the same lumen diameters, such that there is no trend towards centrifugally increasing lumen diameters; and second, de novo cell files commonly appear within the wood. The outwards rate of cambial circumference expansion closely tracks the outwards rate of new wood tracheid file appearance, suggesting that the addition of new files is the primary way the cambium expanded proximally. Because this vasculature can only be studied in transverse section, the developmental mode producing new files cannot be determined. However, evidence from this specimen is sufficient to demonstrate that arborescent lycopsid wood production was more complex than previously understood. [ABSTRACT FROM AUTHOR]

Endemic to the Neotropics, Monnina is the second largest genus of Polygalaceae, yet little is known about its phylogenetic history, biogeography, and morphological character evolution. To address these knowledge gaps, we conducted Bayesian and maximum likelihood (ML) analyses of nuclear ITS and plastid trnL–F regions to test the monophyly of Monnina s.l. We used this phylogenetic framework to (i) infer divergence time estimates of lineages within the genus and reconstruct their historical biogeography; (ii) reconstruct the evolution of morphological characters of putative ecological and evolutionary importance in Monnina ; and (iii) test for correlations between our phylogenetic hypothesis and environmental data. Our results reveal that Monnina is monophyletic with an indehiscent, 1–2-seeded fruit as a synapomorphy for the genus. We identify six clades within Monnina based on our combined phylogenetic results: Clades A, B, and D are primarily distributed in southern and eastern South America, Clades C and E are primarily Central Andean, and Clade F is chiefly distributed in the Northern Andes and Central America. The ancestor of the Monnina stem lineage dispersed from Australia/Africa to South America during the late Eocene to early Oligocene. The divergences of major lineages within the genus began in the early Miocene. We inferred the most recent common ancestor of Monnina to be an herbaceous plant with one-seeded samaroid fruits. The origins of fleshy fruits and shrubby habits are phylogenetically correlated within Monnina , and their concerted convergent evolution may have promoted increased net diversification rates in the two most species-rich subclades of the genus. [ABSTRACT FROM AUTHOR]

The orbicules are tiny structures of sporopollenin that occur on the interior wall of anthers in several groups of plants, and they are associated with pollen grains and tapetal cells. Although their function remains still unresolved, they have been widely used in systematics. Rubiaceae is one of the most studied families in this aspect. However, scarce information is available about the orbicules in the tribe Spermacoceae, especially in the Spermacoce clade. The main objectives of this work were to investigate the occurrence, general morphology, evolution, and systematic utility of the orbicular characters in the Spermacoce clade. We investigated the presence/absence, size, abundance, shape, and ornamentation of orbicules in 104 specimens from 84 species in the Spermacoce clade using scanning electron microscopy (SEM). On the basis of these features, the ancestral state reconstruction analyses were performed on a custom-made phylogeny by stochastic character mapping. The orbicules are present in 38 (44%) of 84 analysed species, corresponding to 13 genera (56%) of the Spermacoce clade. Seven genera have orbicules in all analysed species, eight genera lack orbicules in all analysed species, and six genera show both presence and absence of orbicules. The absence of orbicules was estimated to be the ancestral state for the Spermacoce clade and the presence of orbicules evolved several times independently within Clade B. The absence of orbicules in the common ancestor of the Spermacoce clade can be seen as one of the independent losses that occurred during the evolutionary history of the Rubiaceae. [ABSTRACT FROM AUTHOR]

In a recent research article by Pace et al. (2019) , the authors claimed to have used information from phenology, morphology and molecular phylogenetics in their nomenclatural review of the Spiranthes sinensis complex. However, there are several scientific and botanical nomenclature issues with the Pace et al. (2019) paper in addition to its many errors and misinformation, which can be severely misleading and have the potential to affect our understanding of the highly complex Asian Spiranthes group. Here, we compare and critique their study in light of our study published prior to the article in the Botanical Journal of the Linnean Society. We suggest that the authors should have resorted to improved and new molecular data and a truly integrative analysis to support: (1) re-circumscription of the S. sinensis species complex for each of the six species they recognized, and the treatment of S. hongkongensis as a hybrid; and (2) all the new synonymies they proposed for Asian Spiranthes. [ABSTRACT FROM AUTHOR]

The increasing availability of DNA sequence data, in particular target enrichment data based on the universal Angiosperms353 probe set, but also accumulated Sanger data from previous phylogenetic studies, is facilitating the placement of taxa that are difficult to place with certainty based on morphological evidence alone. Here, we investigate phylogenetic relationships of Medinilla mirabilis (Melastomataceae), a species distributed in central Africa and currently classified in the mega-diverse genus Medinilla of tribe Sonerileae. Medinilla mirabilis is a twining liana with verticillate leaves when young, spherical inflorescences, 4-merous flowers, dimorphic stamens, and baccate fruits. Our results revealed that M. mirabilis is sister to tribe Dissochaeteae and only distantly related to Medinilla. We also provide new data on wood anatomical and seed morphological characters of M. mirabilis. The alternate inter-vessel pits in M. mirabilis and Dissochaeteae are consistent with the phylogenetic placement. Seeds of M. mirabilis are similar to those of Dissochaeteae and of Medinilla. Due to its unique morphology and phylogenetic position, we propose to reinstate the monospecific genus Myrianthemum with Myrianthemum mirabile. This necessitates expansion of the Southeast Asian tribe Dissochaeteae to include Myrianthemum as its only African member. Our study of M. mirabile demonstrates that the combined application of Angiosperms353 and Sanger data is a cost-effective approach to phylogenetically place enigmatic taxa. [ABSTRACT FROM AUTHOR]

The first phylogenomic study using a custom target capture bait panel within the Isonandreae tribe in Sapotaceae is presented. The combination of taxon-specific and universal loci from the Angiosperms353 probe set achieved high species resolution within the genus Palaquium and provides the first phylogenomic insights into Malesian representatives of Sapotaceae, where relationships between taxa often remain poorly understood. The results highlight that generic and some species circumscriptions require further investigation and possible revision: Aulandra longifolia is found to be nested in Palaquium , and P. rostratum within P. microphyllum. Population structure analysis produced limited resolution between and within species, but the bait set was able to recover parameters that are potentially useful in population genomic studies. [ABSTRACT FROM AUTHOR]

Intracellular gene transfer is widely recognized as one of the most important driving forces for species evolution. Here we investigated transferred cytoplasmic motifs in green plants including spore-bearing plants and seed-bearing plants (hereafter termed spore plants and seed plants). Our analyses revealed that gene transfer in spore plants was characterized by shorter motifs than that of seed plants. Several spore species did not exhibit intracellular gene transfer. Meanwhile, high frequency transferred tRNA genes were identified with average values of minimum free energy at moderate level. From the chloroplast to the mitochondrial genome, trnP was found to have transferred with high frequency in green plants. In gene transfer from the mitochondrial to the chloroplast genome, trnN was found to be a highly transferred gene. We observed that several tRNA genes including trnF , trnW , and trnN were involved in bidirectional transfer, which may be related to application strategy of functional protein-coding genes in a plant's adaptive evolution. Codon Adaptation Index (CAI) analysis showed that codon usage was unbalanced in spore and seed plants. CAI values for seed plants were higher than those for spore plants in general, which may reveal rapid divergence adaptability of codon usage in the former. These results provide novel insights into gene transfer and codon usage within cytoplasmic genomes. [ABSTRACT FROM AUTHOR]

Southern Patagonia contains several Eocene fossiliferous deposits that have only been superficially explored and studied. One of these corresponds to the La Marcelina Formation with outcrops in the south-western slope of the Deseado Massif, Santa Cruz Province, Argentina. No detailed palynological studies have been performed so far in this unit. Here we estimate the age, palaeoenvironment, and climatic conditions based on the analysis of terrestrially derived spores, algae cysts, and pollen grains. The recovered association supports an Eocene age and concurs with a mixed flora, including Gondwanan and Neotropical elements, dominated by Podocarpaceae, Nothofagaceae, and Proteaceae, and that probably developed under a temperate and humid climate. Overall, these results expand our understanding of the composition of Eocene floras from the highest latitudes of South America, as well as provide new evidence of past paleoclimates for the area. [ABSTRACT FROM AUTHOR]

Mutualistic plant-pollinator interactions play a critical role in the diversification of flowering plants. The spatiotemporal correlates of such interactions can be understood in a phylogenetic context. Here, we generate ddRAD-seq data for the highly diverse Vriesea-Stigmatodon lineage to test for correlated trait evolution among pollination syndromes and life form, habitat type, and altitude. Our results show that pollination syndromes are correlated with changes in life form and habitat type. The ancestor of the Vriesea-Stigmatodon lineage was likely bat pollinated, rock dwelling and inhabited open, mid-elevation forests. Transitions from bat to hummingbird pollination are correlated with transitions to the epiphytic life form in shaded habitats, whereas bat pollination is correlated with the rock-dwelling life form and open habitats. Our dated phylogenetic tree reveals independent origins of hummingbird pollination, occurring twice in Vriesea at c. 5.8 and 5.4 Mya. The timing for the shifts in pollination syndrome coincides with geological and environmental transformations across the Serra do Mar Mountain Chain, which increased habitat heterogeneity where Vriesea and their mutualists diversified. The phylogenetic tree reinforces the non-monophyly of taxonomic sections within the genus Vriesea previously defined by flower morphology, indicating that some lineages should be treated as species complexes. This study identifies synergetic drivers of speciation in a tropical biodiversity hotspot. [ABSTRACT FROM AUTHOR]

The evolutionary history of herbaceous species in the Northern Hemisphere remains poorly understood. The genus Cerastium is one of the most species-rich herbaceous genera in the Alsineae (Caryophyllaceae), and is mainly distributed in the Northern Hemisphere. Thus, it provides an ideal opportunity to explore the biogeographical history of herbs in the Northern Hemisphere. Here, we present a comprehensive phylogenetic tree for Cerastium with 75 species based on one nuclear and five plastid DNA markers. We then use an integrated phylogenetic, molecular dating, biogeographical, and diversification rate method to examine the spatiotemporal evolution of Cerastium. Cerastium is strongly supported as monophyletic and contains three major clades (Orthodon, Strephodon, and C. fragillimum). Cerastium originated from Europe in the middle Miocene (c. 13.45 million years ago), and subsequently colonized the New World, Africa, Asia, and Australasia through multiple intercontinental dispersal events. The dispersal of Cerastium from Europe (to both the East and West) and subsequent diversifications contributed to the formation of its contemporary Holarctic distribution pattern. The genus experienced rapid lineage accumulation during the late Miocene, possibly coinciding with a global decrease in temperature. These findings highlight the importance of the Northern Hemisphere in herbaceous species diversification in the late Miocene and Pliocene, and will deepen our understanding of the evolution of herbaceous plants. [ABSTRACT FROM AUTHOR]

Epimedium and Plagiorhegma are the representatives of two early-diverging clades in Podophylloideae of Berberidaceae. Flowers are dimerous and trimerous respectively, but their floral development is little known. Here, we used scanning electron microscopy to clarify the structure and development of flower and inflorescence in E pimedium pubescens and P lagiorhegma dubium and compared these with other Berberidaceae to better understand floral evolution within the family. Our results show that the two genera share some significant features. The petal and stamen primordia emerge independently. The carpel is ascidiate from the earliest stages of development. The ovule is anatropous and bitegmic. However, E. pubescens has a paniculate inflorescence, while a lateral floral bud is initiated but aborted in P. dubium. In E. pubescens , both inner sepals and petals are delayed compared with other organs (vs. delay in petal development only for P. dubium). Petals of E. pubescens have a nectariferous spur (vs. no nectariferous tissue for P. dubium). The style of E. pubescens is long with a flat stigma (vs. short with trumpet-shaped stigma for P. dubium). These differences suggest that Epimedium and Plagiorhegma may not be closely related and support placing them separately in two clades of Podophylloideae, complementing results from molecular studies. [ABSTRACT FROM AUTHOR]

Trichomes are key functional traits that protect plants against abiotic stresses, herbivores and pathogens. In addition to their ecological roles, trichomes show high morphological variability in many lineages, providing useful characters for species characterization and taxon delimitation. Here, we focus on trichomes in Croton , a megadiverse genus (c. 1200 spp.) of Euphorbiaceae, in which these structures are ubiquitous and exhibit significant variation in form, location on the plant body, density and function. Owing to their functional and taxonomic relevance and the current need for further standardization of their terminology and classification, we revised previous trichome classifications used in the genus. We also provide new trichome data by expanding taxon sampling and using different methodological approaches in plant anatomy to improve understanding of the structural patterns of the trichome types present in the genus. On the basis of our results and literature review, we propose a new classification for trichomes in Croton based on well-defined parameters; this clarifies existing redundancies, is consistent with anatomical evidence and can be easily updated as new types are revealed in future surveys. This contribution will improve communication among taxonomists and promote more meaningful morphological comparability across systematics studies, including those focusing on morphological evolution and functional traits. [ABSTRACT FROM AUTHOR]

The early-branching clades of Fabaceae subfamily Papilionoideae are characterized by their remarkable lability in floral architecture. In contrast, more derived papilionoid lineages are marked by evolutionary conservatism towards strongly bilateral, papilionate flowers. Here, we show an unexpected example of conservatism of a unique floral architecture during the early diversification history of the papilionoids. We built the most comprehensively sampled molecular phylogenetic tree with a focus on the early-diverging papilionoid Dipterygeae clade to evaluate conservatism of the winged papilionate architecture and associated traits related to flower specialization (e.g. zygomorphy, petal differentiation, stable stamen number and stamen sheath). Dipterygeae comprise c. 22 species of mostly giant trees from across tropical forests in Central America and the Amazon, but they are also ecologically dominant in the savannas of the Brazilian Central Plateau. Phylogenetic analyses of nuclear ribosomal ITS/5.8S and plastid matK and trnL intron sequences strongly supported inter-relationships and the monophyly of each genus (Dipteryx , Monopteryx , Pterodon and Taralea). Bayesian relaxed-clock dating and a Bayesian model of ancestral character estimation revealed c. 30 Myr of conservatism of all winged papilionate-related flower traits in a clade comprising the most recent common ancestor of Dipteryx , Pterodon and Taralea , but lability in fruit morphology during the diversification of the entire Dipterygeae clade. Despite Monopteryx and remaining Dipterygeae being florally discrepant, they are collectively defined by a floral synapomorphy that is unique among all papilionoid Fabaceae: the highly differentiated calyx, where the two upper lobes are enlarged and wing-like, whereas the other three lower lobes are reduced. We suggest that the different dispersal strategies and the ancient winged papilionate floral conservatism in Dipterygeae, which has maintained effective ecological interactions with specialized pollinators and ensured the protection of young flower buds and developing fruits, may explain successful evolutionary and ecological persistence of the clade across the main Neotropical biomes. [ABSTRACT FROM AUTHOR]

Quercus (oaks) is a large and important genus of woody angiosperms occurring in a wide range of environments and often occupying a dominant position in temperate forests of the Northern Hemisphere or being a minor component in some subtropical and tropical forests. A reliable determination of fossil dispersed oak pollen requires combined light, scanning electron (SEM) and transmission electron microscopy (TEM) studies and relevant comparative data on extant oak species. We provide SEM and TEM data on 22 extant Quercus spp. representing all sections of the genus. The main objectives of our study were to clarify the nature of the so-called geniculus, a characteristic equatorial bulge in the exine of the colpus found in many oak species, and to test previous hypotheses about the structural basic units of the exine in Quercus. Our ontogenetic study and oxidative experiment involving several Quercus spp. and one Trigonobalanus sp. resulted in a more accurate interpretation of the nature of the geniculus and exine elements, their different developmental states and, therefore, their more reliable application in the systematics and evolution of the genus Quercus and Fagaceae in general. [ABSTRACT FROM AUTHOR]

Floral morphological adaptations and composition of secretions aim to ensure reproductive success. Maxillariella is part of the largest subtribe of Orchidaceae, and Maxillariella spp. are important components of the orchid flora of the Neotropics. The aim of this paper was to provide a detailed study of the reproductive biology of three morphologically and geographically distinct species: M. sanguinea , M. variabilis and M. vulcanica. For many years, species in this group were considered rewardless, but several studies have revealed that lips of some species may secrete resins. However, most published research has mainly focused on investigating either micromorphology (SEM, TEM, histochemistry) or fragrance composition (GC–MS). In this study, we make the first attempt to investigate Maxillariella flowers in a more comparative manner by combining both aspects. In all investigated species we reported the presence of resins with lipids, sugars and/or proteins, suggesting a potential role as a food reward. Scant quantities of residues indicate that they are produced periodically in small quantities. Chemical analysis revealed significant differences between species, however, the presence of some compounds was constant. Cycloartenal and cycloartenol (main ingredients of resin and wax-like material in some Maxillariinae) were not been found. [ABSTRACT FROM AUTHOR]

Downloaded from https://academic.oup.com/botlinnean/article/195/3/249/6106223 by 81695661, OUP on 03 March 2021 PLANT ANATOMY: AT THE HEART OF MODERN BOTANY 251 © 2021 The Linnean Society of London, Botanical Journal of the Linnean Society, 2021, 195, 249-253 Selaginella moellendorffii Hieron. has a shoot apical meristem with only one initial cell, but this is unlikely to be an ancestral lycopod meristem type. 249 © 2021 The Linnean Society of London, Botanical Journal of the Linnean Society, 2021, 195, 249-253 Botanical Journal of the Linnean Society, 2021, 195, 249-253. More importantly, developmental biology of plants explores functioning of plant meristems and aspects of cell and tissue differentiation, the topics that have a long history of research in the framework of plant anatomy. © 2021 The Linnean Society of London, Botanical Journal of the Linnean Society, 2021, 195, 249-253 Professor A.C. Timonin, an English translation of her work on classification of plant meristems has been recently published (Lotova, 2020). [Extracted from the article]

Nodes are interfaces between stems and leaves. Vascular bundles originate here and elongate into leaves and internodes. In Marantaceae, internodal bundles are highly diverse, including inverted bundles in the climbing genus Haumania. The objective of this paper is to characterize bundle forms, their position across the stem and their connection to leaves and short shoots in Haumania spp. and other unrelated African branch-angle climbers in the family (Hypselodelphys , Trachyphrynium). We question whether bundle inversion is a genus-specific trait in Haumania or related to the climbing growth form. Vascular bundles in internodes are scattered across the stem diameter in a characteristic pattern. Four (to five) bundle types follow each other in a centripetal order from highly sclerenchymatic 'a'-bundles close to the epidermis to 'd'-bundles in the centre with a low sclerenchyma proportion. Inverted bundles only appear in internodes of Haumania , making this trait a synapomorphy for the genus. The nodes show stem, leaf and short shoot bundles in a remarkably diverse pattern with partitioned phloem clusters and apparently augmented xylem elements. Our preliminary conclusion is that the inversion of bundles happens when leaf and short shoot traces join the main axis bundle layers. [ABSTRACT FROM AUTHOR]

Understanding vascular bundle systems in angiosperms is a challenge. On the one hand, the vascular tissue is extremely important in reconstructing the evolution and survivability of plants, but on the other hand, it forms a complicated three-dimensional system of controversially discussed phylogenetic and ontogenetic origin. To increase clarity, in this paper we briefly summarize histological, phylogenetic and molecular aspects of primary vascular bundle formation in angiosperms, adding histological data on early stages of vascular bundle formation, proposing a concept combining the different views and providing simplified illustrations to improve the understanding of primary vascular systems in angiosperms. Based on the auxin hypothesis, vascular bundle formation is stimulated by the development of leaf primordia. Provascular domains appear at the base of the leaf primordia and develop into two directions (leaf, internode). The low vs. high number of internodal bundles, their circular vs. scattered arrangement and the open vs. closed bundle construction in eudicots vs. monocots can be deduced to be due to processes below the shoot apical meristem. The most important processes distinguishing monocots from eudicots are the isolated bundle initiation outside the primary meristem, the enormous expansion of the leaf bases associated with a high number of vascular bundles and the early onset of primary thickening passively dislocating vascular bundles. [ABSTRACT FROM AUTHOR]

Orchidaceae show remarkable diversity in pollination strategies, but how these strategies vary globally is not entirely clear. To identify regions and taxa that are data-rich and lend themselves to rigorous analyses or are data-poor and need attention, we introduce a global database of orchid reproductive biology. Our database contains > 2900 species representing all orchid subfamilies and 23 of 24 tribes. We tabulated information on habit, breeding systems, means of pollinator attraction and the identity of pollinators. Patterns of reproductive biology by habit, geography and taxonomy are presented graphically and analysed statistically. On the basis of our database, most orchid species sampled are pollinator dependent (76%) and self-compatible (88%). Pollinator attraction based on rewards occurs in 54% of the species, whereas 46% use some means of deceit. Orchids generally have highly specific pollinator interactions (median number of pollinator species = 1). Nonetheless, on average, specificity is lower for species offering rewards, occurring in multiple continental regions or Northern America (as defined by the Taxonomic Database Working Group Level 1 regions). Although our database reveals impressive knowledge gains, extensive gaps in basic observations of orchid reproductive biology exist, particularly in tropical regions and diverse lineages of fly-pollinated species. The database is expected to facilitate targeted studies, further elucidating the ecological and evolutionary drivers of orchid diversity. [ABSTRACT FROM AUTHOR]

We use Helianthemum oelandicum subsp. oelandicum as a model for studies of mechanisms shaping the diversity in a rapidly radiating lineage of the H. oelandicum aggregate. Locally, correlations between drainage conditions (using GIS to measure variation in the micro-topography on the more or less horizontal bedrock) and frequency of alleles of Mendelian genes for pubescence indicated that hairs are markers of adaptation to the unique environmental conditions (drought and periodic flooding) on the alvar habitats of Öland. An allozyme study showed that 1 and 4% of the genetic diversity is partitioned among two varieties and natural populations, respectively. F ST for hair alleles was up to ten time greater than F ST for allozymes. Öland rose above sea level after the LGM, which makes it possible to date the onset of the post-glacial diversification on the island. Only two, mainly allopatric, plastid DNA haplotypes were detected, H1 and H2. The southern Helianthemum oelandicum subsp. oelandicum var. canescens has only H1, whereas the more widespread var. oelandicum possesses both haplotypes. A restricted occurrence of haplotype H1 in the core area of var. oelandicum in the central Öland, coincided with the highest elevation on the island, probably representing the post-glacial arrival of the species on the island. [ABSTRACT FROM AUTHOR]

The structural details of the gynoecium are key to understanding the reproductive systems and successful diversification of flowering plants. However, the gynoecium morpho-anatomy in South American species of Cactaceae that evolved in the Andean region remains largely unknown. Here we selected 18 species, most of them of evolutionarily related genera of Cactaceae tribe Trichocereeae, to conduct a detailed comparative study. Observations were made using light, fluorescence, differential interference contrast and scanning electron microscopy. Most of the characters of the ovary and ovule were typical of the family, except for the nucellar beak in Echinopsis aurea and E. haematantha , here reported for the first time in cacti. We found evidence suggesting that the stigmatic surface covered with multiseriate trichomes, the semi-closed style type and the pollen tube transmitting tract are conserved characters among species of Trichocereeae; this finding may be explained by a phylogenetic conservatism of the investigated genera of the tribe. We integrated the available information about structural and histological characters of the gynoecium in the family, taking into account the current phylogenetic context of the examined genera. Our results reinforce the significance of floral anatomical traits for the systematics of Cactaceae. [ABSTRACT FROM AUTHOR]

Many Neotropical tree species are widespread at continental and even inter-continental scales, but phenotypic variation across their respective ranges has rarely been quantified. We measured traits in the widespread, unisexual Neotropical tree Virola sebifera (Myristicaceae) across its continental-scale range, and predicted that, given its hyperdominant status, generalist-pollinated flower type, high dispersal capacity and wide ecological amplitude there would be: (1) a weak relationship among and within reproductive and vegetative characters with environmental, spatial and biome correlates; (2) undetectable canalization of reproductive traits; and (3) high phenotypic variation of vegetative characters. We measured five foliar and seven floral traits from 187 male-expressing individuals of V. sebifera in specimens collected from Central to South America. Spatial regression models were employed to test for the importance of distance, elevation, mean annual rainfall and temperature on phenotypic variation. Pairwise correlations of vegetative and reproductive characters were calculated to examine intraspecific trait variation among and within these two classes. We found that most phenotypic variation was weakly explained by spatial predictors such as certain major South American domains like the Andes Cordillera and the Amazon Basin. Within-class comparisons of floral characters were no different than among-class (floral-foliar) correlates, suggesting the absence of canalization of reproductive structures. Greater phenotypic variation in flowers relative to leaves may be due to the generalist pollinator regime and high dispersal capacity thus relaxing divergences in the evolutionary process of its floral morphology. The results of these morphometric analyses (e.g. weak signals of isolation by distance) in combination with the biology of this Neotropical tree suggest that V. sebifera operates as a well-dispersed metapopulation across most of its range. [ABSTRACT FROM AUTHOR]

The transition from a greenhouse to an icehouse world at the Eocene-Oligocene Transition (EOT) coincided with a large decrease of pollen from the steppe-adapted genus Nitraria. This genus, now common along the Mediterranean coast, Asia and Australia, has a proposed coastal origin and a geographically widespread fossil record. Here we investigated the evolution, taxonomic diversity and morphological disparity of Nitraria throughout the Cenozoic by integrating extant taxa and fossil palynological morphotypes into a unified phylogenetic framework based on both DNA sequences and pollen morphological data. We present the oldest fossil pollen grain of Nitraria , at least 53 Myr old. This fossil was found in Central Asian deposits, providing new evidence for its origin in this area. We found that the EOT is an evolutionary bottleneck for Nitraria , coinciding with retreat of the proto-Paratethys Sea, a major global cooling event and a turnover in Central Asian steppe vegetation. We infer the crown age of modern Nitraria spp. to be significantly younger (Miocene) than previously estimated (Palaeocene). The diversity trajectory of Nitraria inferred from extant-only taxa differs markedly from one that also considers extinct taxa. Our study demonstrates it is therefore critical to apply an integrative approach to fully understand the plant evolutionary history of Nitrariaceae. [ABSTRACT FROM AUTHOR]

Speculations on hybridization among wild cycads are abundant, but empirical evidence of hybridization in cycad evolution is almost non-existent and the evolutionary consequences of hybridization in cycads have not been discussed. Previously, Zamia katzeriana was hypothesized to have a hybrid origin between two sympatric species: Z. splendens and Z. loddigesii. In this study, we aimed to reveal whether such a hypothesis is confirmed. Variation in 12 microsatellite loci, 12 morphological traits and environmental niche of ten populations representing the three species was examined. Gene flow and scenarios of demographic history were tested. Ecological niche models were reconstructed to examine present and past niche availability of the two putative parental species. Correlations between genetic, morphological, environmental and geographical distances were tested. We found that Z. katzeriana diverged from Z. splendens without experiencing admixture with its sympatric congeners. However, gene flow between Z. splendens and Z. loddigesii has occurred in one locality. The niches of the two latter species have overlapped since the Last Glacial Maximum, when admixture probably occurred. However, the admixed populations do not resemble Z. katzeriana. These results confirm that Z. katzeriana did not originate from hybridization between Z. splendens and Z. loddigesii. [ABSTRACT FROM AUTHOR]

Hymenaea is a genus of Fabaceae easily recognized by vegetative characteristics. However, the circumscription of some species has been historically challenging. The tangled circumscription of H. stigonocarpa has been addressed in several molecular and morphological studies, but some of the morphological confusion has yet to be resolved. Thus, in this study we used population genetics coupled with detailed morphological analyses to improve taxonomic definition in this complex, currently comprising two varieties (H. stigonocarpa vars. stigonocarpa and brevipetiolata). Bayesian and population genetic structure analyses were conducted using nine nuclear microsatellite loci for 1034 individuals from 35 populations. The morphometric analyses were performed using leaflet characters. Our results support the existence of five genetically structured clusters, and morphometric analyses support the recognition of two clusters, emphasizing H. stigonocarpa var. brevipetiolata as an exclusive genetic and morphological group, encouraging us to make changes in its taxonomic ranking. Thus, we propose the adoption of specific status for H. stigonocarpa var. brevipetiolata on the basis of its population genetics and morphology. In addition to the population genetics data and morphological analyses, a taxonomic treatment with illustrations is provided. [ABSTRACT FROM AUTHOR]

Pteropyrum is a small genus of Polygonaceae with four species from the arid regions of Iran and adjacent countries. Pteropyrum spp. are not precisely delimitated and are difficult to identify because of their high plasticity in morphological characters. Pteropyrum (C3) has a close affinity to Calligonum (C4) and is therefore a suitable case for C4 evolutionary studies. We investigated the morphology and micromorphology (including pollen morphology) of Pteropyrum and elucidated the phylogenetic relationships with Atraphaxis and Calligonum using nuclear ITS sequences. Characteristics of the photosynthetic tissues such as volume and number of layers of primary carbon assimilation tissues (PCA) and photosynthetic carbon reduction tissue (PCR) were studied. In addition, the leaf and cotyledon anatomical characters of Pteropyrum (C3), Atraphaxis (C3) and Calligonum (C4), and their δ 13C values were compared to look for evolutionary changes in assimilating organs. The molecular phylogenetic tree identifies two strongly supported clades in Pteropyrum and its close relationship with Calligonum , confirming previous studies. Some morphologically similar species belong to different clades, which is probably due to convergent evolution and homoplasy. Leaf anatomical studies show that Atraphaxis has a multilayered mesophyll tissue, whereas Calligonum has one-layered mesophyll cells. The volume and layer number of mesophyll tissue cells decreases, whereas water storage tissue area significantly increases from Atraphaxis to Pteropyrum and Calligonum. This phenomenon confirms previous studies in other lineages with C4 salsoloid anatomy that have evolved through increasing of water storage tissue and succulence of assimilating organs. In the taxonomic part of the paper, a key to identification of accepted taxa of Pteropyrum , description of species and distribution maps are presented based on numerous herbarium specimens and our own rich collections from the field. Four new species are described based on a combination of morphology of seedlings and mature plants, pollen morphology and molecular data. A subspecific classification is suggested to show morpho-geographical variation of Pteropyrum aucheri s.l. [ABSTRACT FROM AUTHOR]

Discolobium and Riedeliella , exclusively South American genera, have been shown in phylogenetic analyses to be the sister group to the Pterocarpus clade. The species of the two genera can be confused when reproductive structures are absent, resulting in taxonomic misunderstandings in botanical collections. This study aimed to investigate the anatomical characters of leaflets of representatives of Discolobium and Riedeliella in terms of their diagnostic value at the genus and species levels and to provide information about the type, location and histochemistry of their secretory structures, and their usefulness for the systematics of the genera. The taxa were analysed using light microscopy and scanning electron microscopy. Unistratified epidermis, epidermal cell contour and fibre bundles of the main vein are features shared by the two genera. The position of the stomata and of the tector trichomes and the shape of the epidermal cells and of the mucilaginous idioblasts are diagnostic anatomical features at the genus level. Epidermal mucilaginous idioblasts are confirmed for all species studied. Phenolic idioblasts are present in Riedeliella and Discolobium , and secretory trichomes are found only in Discolobium. The anatomical characters of the leaflets are useful for the taxonomy of all species studied. Furthermore, our dataset shows novelties for the systematics of Fabaceae. [ABSTRACT FROM AUTHOR]

As recently circumscribed, Sesamum was rendered monophyletic by including the three segregate genera Ceratotheca , Dicerocaryum and Josephinia. Here, the monophyly of Sesamum and the currently accepted infrageneric taxa was tested using expanded phylogenetic analyses. In addition, nine taxonomically useful morphological characters were optimized on the resulting phylogenetic tree to assess their evolutionary pattern. The phylogenetic analyses support the expanded circumscription of Sesamum and the monophyly of Sesamum section Sesamum relative to Sesamum sections Aptera, Ceratotheca , Chamaesesamum , Dicerocaryum , Josephinia and Sesamoptera. Most sections were retrieved as monophyletic, except Sesamum section Ceratotheca which was shown to be paraphyletic. Character reconstruction infers the ancestor of Sesamum to have had an erect growth habit, simple leaves with entire margins, ovaries with incompletely divided locules, indehiscent capsules that are oblong-quadrangular in lateral view with a beaked apex and winged seeds. Relative to the ancestral states, Sesamum has dehiscent fruits and fully divided locules as synapomorphies, with reversals to the ancestral state (indehiscence, undivided locules) in Sesamum sections Josephinia and Dicerocaryum. The absence of trichomes on mature vegetative parts and the development of lobed leaves are synapomorphies for Sesamum section Sesamopteris. Characters such as dentate and lobulate leaf margins and discoid fruit with horn-like protrusions are homoplastic in Sesamum. Dated phylogeny and ancestral range estimation suggest a southern African origin for the genus with subsequent diversification to tropical Africa, India and Australia. Sesamum has an estimated crown age of 38.1 ± 5.2 Myr with subsequent dispersal scenarios into tropical Africa, Asia and Australia during the Miocene from 24.5 Mya. Dispersal, rather than continental vicariance, is the probable explanation for the pantropical distribution of Sesamum. [ABSTRACT FROM AUTHOR]

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

Natural hybrids in Triticeae have been frequently reported from the Qinghai–Tibet plateau, but minor variation in morphological features and homoploid hybridization have made it difficult to identify the origin and genome constitution of hybrids between Elymus and Campeiostachys. Specimens were investigated using morphology, cytogenetics and phylogenetic analyses to uncover the genome constitution and origin of ten putative natural hybrids (SH01-SH10) from the Qinghai–Tibet plateau. SH01, SH02, SH03, SH05 and SH06 (2 n  = 5 x  = 35, StStHHY) originated from Campeiostachys breviaristata (2 n  = 6 x  = 42, StStHHYY) and Elymus sibiricus (2n = 4x = 28, StStHH); SH04 and SH07 (2 n  = 5 x  = 35, StStHHY) originated from C. nutans (2 n  = 6 x  = 42, StStHHYY) and E. sibiricus ; SH08 (2 n  = 5 x  = 35, StStHHY) originated from C. dahurica var. tangutorum (2 n  = 6 x  = 42, StStHHYY) and E. sibiricus ; and SH09 and SH10 (2 n  = 4 x  = 28, StStHH) were the homoploid hybrids of E. sibiricus and an unknown Elymus sp. (2 n  = 4 x  = 28, StStHH). Karyotype variations in SH04 and SH07 might originate from the maternal progenitor. Frequent hybridization in the Qinghai–Tibet plateau might result from factors such as genome constitution, pollination habits, overlapping flowering stage, sympatric distribution and unique ecological conditions. [ABSTRACT FROM AUTHOR]

Species of flora and fauna occurring in the west of Ireland and south-west Europe, known as Lusitanian elements, constitute a puzzling case of isolated populations of uncertain origin. Here we studied the population genetic structure of the heather Erica mackayana in Ireland and northern Spain and compared it with its widespread close relative Erica tetralix using single nucleotide polymorphisms (SNPs). We reconstructed phylogenetic relationships using maximum likelihood (ML), inferred population genetic structure using cluster assignment and principal component analysis, and estimated population genetic diversity. The cluster analysis and ML phylogenetic tree showed a geographical pattern for E. tetralix supporting a post-glacial migration from Iberia to Ireland. In contrast, Irish populations of E. mackayana were supported in independent clades in the phylogenetic tree and shared clusters with Iberian populations in the structure analysis, and F ST values were lower among Irish and Spanish populations than among Irish ones. This suggests that Irish populations of E. mackayana are the result of recent multiple independent introductions from its native area in northern Spain, probably assisted by humans. However, the origin of the largest Irish population at Roundstone Bog is unclear and should be further investigated. Post-glacial, long-distance dispersal is the most plausible explanation for Lusitanian species distribution in Ireland. [ABSTRACT FROM AUTHOR]

Species with wide ranges often exhibit morphological variability that is mostly shaped by ecological and evolutionary processes, and the resulting diversity is frequently reflected in intraspecific taxonomy. Dianthus sylvestris in the Balkan Peninsula encompasses six subspecies (D. sylvestris subspp. alboroseus , bertisceus , kozjakensis , nodosus , sylvestris and tergestinus), the identification of which is problematic due to a great morphological variability and complex patterns of environmental variation. To explore morphological variation of described subspecies and to investigate how their morphology varies in relation to environmental variations across their geographical distribution, we evaluated 97 populations of D. sylvestris for variability in 25 morphological characters and 20 environmental variables. Number and shape of epicalyx scales, calyx length and petal denticulation captured the greatest extent of morphological variability between populations. Morphometric analyses revealed a continuous variability in quantitative morphological characters and an absence of clear morphological differentiation between the investigated subspecies. However, two main morphologically distinct entities, the north-western Balkan populations and the south-eastern Balkan populations, were identified and they were split approximately along the Neretva River valley. In addition, our results indicate that environment, rather than geography, plays a potentially more important role in shaping the morphological variability of this taxon. Overall, our results do not support the recognition of the described subspecies or the currently accepted taxonomic concept, instead pointing to a continuous morphological variability of D. sylvestris in the Balkan Peninsula. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Species limits in Piper spp. have been unstable, with specimens often assigned to different species by different botanists. Using a strongly supported clade of Asian Piper section Muldera, I investigated species boundaries in the eight Malay Peninsula species using morphological, anatomical and molecular approaches. I assessed morphological variation using principal component analysis (PCA) and a model-based clustering method. Herbarium specimens and samples collected in the field were examined, and the latter were also used to examine variation in vegetative anatomy. Potential evidence of reciprocal monophyly of species came from the molecular phylogenetic analyses of nuclear ITS and g3pdh and plastid trnL-F. Morphological analyses did not lend support for any of the hypothesized species from the Malay Peninsula. Nuclear phylogenetic trees supported a combination of Piper schizonephros, Piper polygynum and Piper maingayi as a single species that might also have a distinct distribution of calcium oxalate crystals in the mesophyll of the leaf and a prominently raised leaf midrib raise. Nevertheless, shared characters between this species and some, but not all, of the other morphogroups, and paraphyly of other morphogroups in the phylogenetic analyses, might suggest hybridization or lateral gene transfer among species of the section Muldera. In-depth population studies coupled with examination of morphological variation for all species of the section Muldera, including those from outside the Malay Peninsula, are necessary to disentangle the species limits and ultimately the evolutionary history in this group. [ABSTRACT FROM AUTHOR]