American Journal of Botany

Morus rubra is native to the eastern United States, with its range extending into the Upper Midwest and southern Ontario, Canada. Its present distribution suggests that past glacial events in North America may have influenced the genetic structure of populations at the species northwestern range boundary. This study assessed genetic variation among six M. rubra populations believed to have experienced postglacial colonization using published nuclear microsatellite markers and sequences from the chloroplast trnL-trnF region. Five nuclear microsatellite markers previously developed for M. alba were successfully transferred to M. rubra, while the chloroplast trnL-trnF region provided an additional marker for evaluating chlorotype diversity. Nuclear microsatellite diversity was higher in southern unglaciated populations than in northern glaciated populations, a pattern consistent with the observed distribution of chlorotype diversity. Together, these results support ancient founder effects associated with leading-edge expansion following glacial recession and suggest that postglacial colonization contributed to the present-day genetic structure of M. rubra at its northwestern range boundary. Because M. rubra hybridizes with the naturalized invasive M. alba, reduced genetic diversity in marginal populations may increase their vulnerability to genetic swamping. The markers characterized in this study provide useful tools for population genetic research in Morus, and the findings have important implications for the conservation and management of marginal and threatened M. rubra populations in the Upper Midwest.

IntroductionMany plant species secrete nectar to attract beneficial animals. The chemical composition of floral nectar influences pollinator nutrition and behavior, as well as microbial growth in flowers. Yet factors that predict nectar composition across plant species, as well as chemical compounds determining microbial growth in nectar, remain poorly understood. MethodsWe used both targeted and untargeted metabolomics to compare the nectar chemical profiles across 31 phylogenetically diverse plant species that span a range of floral morphologies. We examined the common classes of compounds detected in nectar and patterns of co-occurrence among them. We combined newly collected chemical data with previously published data on microbial growth in nectar of the same plant species to examine how nectar chemistry is associated with microbial growth. ResultsPlant species and clades varied in amino acid, minor sugar, and secondary metabolite composition and concentration. Sampled rosids and lilioids generally contained higher amino acids while asterids contained greater concentrations of oligosaccharides and sugar alcohols. Across plant species, proteinogenic amino acids frequently co-occurred in nectar but many were negatively associated with sucrose concentration. Plant species with greater concentrations of amino acids and other nitrogen-containing compounds hosted greater microbial density in nectar, while some other compound groups were negatively associated with microbial diversity. ConclusionsNegative correlations between nectar amino acid and sucrose concentration across species suggest ecological tradeoffs or physiological constraints in nectar composition. Given that the growth of common nectar microbes is limited by amino acid concentration, these findings suggest an ecological cost to amino acid production in nectar. Finally, we document variation among species in nectar vitamins, non proteinogenic amino acids and secondary metabolites with hypothesized yet currently untested ecological roles.

Background. DNA-based molecular markers underpin plant genetic diversity assessment, germplasm characterisation, and conservation prioritisation. Four marker systems dominate the field: Amplified Fragment Length polymorphisms (AFLPs), simple sequence repeats (SSRs), single nucleotide polymorphisms (SNPs), and random amplified polymorphic DNA (RAPDs). No quantitative meta-analysis had pooled their performance on the canonical diversity metrics: polymorphism information content (PIC), expected heterozygosity (He), and resolution power, across plants. Existing reviews are narrative, marker-restricted, or qualitatively conclusive of infeasibility. Methods. A PRISMA 2020-compliant systematic review (registered at the Open Science Framework) was executed. Eligible studies were within-study paired comparisons genotyping the same accession panel with at least two of {SNP, SSR, AFLP, RAPD} and reporting at least one diversity metric. Effect sizes were paired standardised mean differences (Hedges' g) computed under the Bernoulli-variance approximation. Random-effects REML meta-analysis used metafor 5.0.1 with Knapp-Hartung adjustment, leave-one-out, and r-sensitivity. Results. Fifteen within-study paired contrasts were eligible, distributed across three pools. Pool 2 (SSR vs SNP, He, k = 5) yielded a pooled Hedges' g of 0.494 (95% CI: -0.078 to 1.066, p = 0.075; I-squared = 90.2%; 95% PI [-0.82, 1.81]). SSRs exceeded SNPs on He in 4 of 5 studies; leave-one-out removal of the panel-size-asymmetric outlier raised the estimate to g = 0.644 (p = 0.025). Pool 3a (dominant-marker stratum, k = 6) yielded g = 0.419 (95% CI: -0.121 to 0.960, p = 0.103; I-squared = 56.5%); five of six contrasts showed SSR or AFLP exceeding RAPD on per-locus PIC. Pool 1 (PIC, k = 3, exploratory) gave a consistent direction (g = 0.453). All three pools point in the same direction: codominant or AFLP markers carry more per-locus information than the alternative being compared. Conclusions. SSR markers reported higher per-locus diversity than SNP and RAPD markers in plant within-study paired comparisons, mechanistically grounded in the SNP biallelic ceiling and the multi-allelic richness of SSRs. The effect attenuated or reversed in selfing/low-diversity panels and at the per-panel level when SNP panels exceeded approximately 1000 loci. RAPDs show the lowest per-locus information content of the four classes.

O_LIFloral nectar plays a critical role in shaping the ecology and evolution of plant-pollinator interactions. Effective and efficient methods that allow for broad-scale sampling of nectar volume and sugar concentration across a diversity of taxa are needed to improve our understanding of many dimensions of mutualistic plant-pollinator interactions--including their basic ecology and evolution, their responses to environmental change, and their conservation and restoration. C_LIO_LIDespite the key importance of nectar for mediating plant-pollinator interactions, quantifying floral nectar in the field from many different plant species is challenging because there is often no one-size-fits-all sampling method that is effective across a diversity of floral structures and nectar traits. Different methods require different preparation, and sampling from many species involves a variety of logistical challenges. C_LIO_LIHere we provide a methodological roadmap for sampling floral nectar in the field from many different plant species. We describe our nectar collection methods in detail, including necessary equipment, calculations, and approaches appropriate for different floral morphologies. We also provide a troubleshooting guide for common problems encountered while collecting nectar in the field. To demonstrate the utility and effectiveness of our methods for collecting nectar from many different species, we present results on nectar trait variation from 53 species in an ecosystem. C_LIO_LIOur method illustrates that nectar traits vary considerably within and among plant species, indicating that large-scale nectar sampling projects are an important consideration for many basic and applied questions in pollination ecology and evolution. We hope that across many plant communities and ecosystems, our paper provides a practical roadmap for how to navigate the complexities of quantifying floral nectar traits. C_LI

Shifts in flowering phenology are one of the most well studied plant responses to global climate change. Many studies have documented these shifts and their drivers, including some that describe altered patterns of co-flowering among taxonomically broad species within communities. In comparison, few analyses have examined systematic changes in co-flowering between closely related, interfertile species, where co-flowering can have unique evolutionary consequences. To address such shifts in co-flowering among close relatives, we investigate phenological responses to climate change and its effect on patterns of co-flowering over the past 124 years in 52 species of North America violets (Viola). This genus has many co-occurring species that reproductively interact via shared pollinators and hybridization. We use ~14,000 herbarium records along with environmental and species trait data to model the magnitude of recent flowering phenology shifts, environmental variables and/or species traits associated with these shifts, and resulting changes in co-flowering among species. While both the magnitude and direction of phenological shifts varied among Viola species, nearly half (25/52) show significant changes in flowering day. Regardless of whether flowering was advanced or delayed, flowering date was most consistently associated with local mean temperature. Of six species-level traits, geographical region also significantly predicted flowering shifts, consistent with environment and geography together explaining broad phenological responses across this group. These shifts have produced significant changes to pairwise patterns of co-flowering among species -- ranging from a 59 day increase in co-flowering to complete loss of co-flowering overlap. Sympatric pairs specifically have experienced both increases and decreases in co-flowering, with a geographic pattern of increased co-flowering occurring mainly in eastern US and decreased co-flowering common in western US. Because Viola species are generalist pollinated and already known to hybridize, these new co-flowering patterns could further undermine reproductive barriers among species in this genus.

Leaf shape varies widely across plant taxa and has repeatedly been shown to affect ecophysiology, interspecific interactions, and fitness. We used population genomics, genome wide association studies (GWAS), and comparative genomics to determine the genetic basis and evolutionary history of an uncharacterized Mendelian leaf shape polymorphism in Ipomoea hederacea. To do so, we assembled a reference genome and generated whole genome sequencing for 123 individuals from 55 populations. We identified a 117 kb indel that perfectly co-segregates with leaf shape by conducting a GWAS and assessing differences in coverage. Syntenic orthologs for genes on the indel were present in five other Ipomoea species with various leaf shapes, indicating the indel is newly arisen deletion in I. hederacea despite similar leaf shape phenotypes in the other species. More broadly, these results illustrate how a range of leaf shape phenotypes can be produced by distinct genetic mechanisms even in closely related species. Although none of the genes on the indel itself are known leaf shape candidates, there are multiple leaf shape candidate genes in close proximity that are involved in the auxin biosynthesis pathway. Additionally, the genes within the indel have gene functions that could affect other potentially ecologically relevant traits that have previously been shown to be associated with leaf shape in I. hederacea. Therefore, the pleiotropic effect of the indel polymorphism can have important implications for understanding the ecological mechanisms influencing a well-documented leaf shape latitudinal cline in I. hederacea. Significance StatementIpomoea hederacea has been used to investigate the ecological and evolutionary effects of leaf shape because of a well-documented latitudinal leaf shape cline governed by an uncharacterized Mendelian polymorphism in this species. We identified a 117 kb indel that perfectly co-segregates with leaf shape in I. hederacea. The indel appears to be a distinct genetic mechanism than those governing similar leaf shapes in other closely related Ipomoea species. Additionally, possible pleiotropic effects of the indel on other traits has important implications for understanding the ecology and evolution of leaf shape variation in I. hederacea. Therefore, both the results and the new genomic resources that we developed will help facilitate future work understanding the genetic, developmental, and ecological mechanisms governing leaf shape variation.

Background and AimsThe evolution of reproductive isolation between previously interbreeding populations is a fundamental driver of plant speciation. Within Amaryllidaceae, Nothoscordum represents an evolutionarily complex genus, characterized by an unusually high incidence of chromosomal rearrangements. During fieldwork, Nothoscordum montevidense and Nothoscordum bonariense were found growing in sympatry, along with individuals exhibiting intermediate morphological traits, suggesting a putative hybrid origin. To test this hypothesis, we employed an integrative approach to characterize the morphologically intermediate specimens and the two sympatric populations. Materials and methodsTo characterize the putative hybrids we have combined morphological, cytogenetic analyses (chromosome counts, CMA/DAPI banding, and FISH) and flow cytometry-based genome size estimation. Phylogenetic relationships and genomic structure were also investigated through Genotyping-by-Sequencing (GBS), complete chloroplast genome assembly, and comparative repetitive DNA analysis. We also performed species distribution modeling and phenological analyses of the putative parental species. Key ResultsMultiple lines of evidence confirm the hybrid origin of the studied plants. Cytogenetic analyses revealed specimens with 2n = 21 (1C {approx} 33 pg = 32.274 Mbp) and 2n = 25 (1C {approx} 37 pg = 36.186 Mbp), accompanied by meiotic irregularities consistent with interspecific hybridization. Chloroplast genome phylogeny identified N. montevidense (2n = 16, 1C {approx} 25 pg) as the maternal lineage, while GBS data confirmed N. bonariense (2n = 26, 1C {approx} 41 pg) as the paternal contributor and revealed evidence of subsequent backcrossing. Comparative analysis of repetitive DNA showed reduced 35S rDNA diversity in the hybrid, indicative of post-hybridization genomic restructuring. Despite the observed genomic complexity, no clear morphological differentiation was detected among hybrid individuals. Phenological analyses and species distribution models demonstrated broad overlap between parental species. ConclusionsOur findings highlight the role of hybridization in shaping genome architecture in cytogenetically labile plant lineages. Furthermore, our results underscore that morphological similarity can mask profound genomic complexity, reinforcing the value of integrative approaches to understand genera characterized by reticulate evolution and genomic instability.

Forest trees pose numerous potential challenges to phylogenomic inference. Their large effective population sizes and relatively long generation times lead to deep allele coalescence and consequently incomplete lineage sorting (ILS), which biases inferences of divergence times toward older ages and introduces gene tree discordance. Deep phylogenetic divergences, reaching back into the Paleocene, introduce reference-mapping biases. Introgression--the movement of genes between lineages--may result in different phylogenies being inferred depending on which individuals are included in analysis, even if the plurality of the genome favors the divergence history unaffected by introgression. These factors influence phylogenetic inference across the Tree of Life but are particularly prevalent in forest trees. Oaks (Quercus) are notable for all three influences. In addition, our knowledge of the oak phylogeny is currently based strongly on restriction site associated DNA sequencing (RADseq) datasets published over the past decade, which may introduce additional sources of uncertainty. In this chapter, we analyze a 322-species RADseq dataset and genome resequencing data from across the genus to address sources of uncertainty in our understanding of the global oak phylogeny, which we hope will serve as a model for other research groups working on comparable woody plant groups.

Premise: Genome skimming (GS) is a cost-effective approach for plant phylogenomics, but its ability to recover informative datasets from different genomic compartments, particularly genome-wide SNPs, remains poorly explored in Solanum. Methods: We evaluated shallow GS for phylogenetic inference in South American prickly Solanum lineages by recovering plastid, mitochondrial, and nuclear datasets, including coding regions and genome-wide SNPs. Phylogenies were inferred using maximum-likelihood and coalescent approaches under different SNP filtering strategies. Results: GS successfully recovered complete plastomes, organellar coding regions, and large SNP datasets, but failed to consistently assemble mitochondrial genomes or recover low-copy nuclear genes. SNP-based analyses, especially from the nuclear genome, produced stable, well-supported phylogenies that were largely congruent across inference methods. In contrast, coding-region datasets, particularly from the mitochondrial genome, showed greater topological discordance, revealing cytonuclear conflict. Discussion: Our results demonstrate that shallow GS is an effective strategy for generating informative SNP datasets for phylogenetic inference in Solanum, despite limitations in recovering complete mitochondrial genomes and low-copy nuclear loci. SNP-based analyses substantially expand the phylogenetic potential of GS, providing a practical and cost-effective alternative for systematic studies.

PremiseDrought is intensifying in many regions under climate change, affecting plant growth, phenology, and resource allocation. Plants cope with water limitation through strategies such as escape, avoidance, and tolerance, but how these strategies are reflected in trait variation across natural drought gradients remains poorly understood. We examined how drought-related traits vary across a drought gradient in wild sunflower (Helianthus annuus L.). MethodsWe conducted a common-garden experiment using 19 wild sunflower populations collected across Southern California spanning a climatic moisture deficit gradient. We quantified growth, phenology, morphology, biomass allocation, and physiological traits and evaluated their relationships with climatic moisture deficit and soil variables using regression and correlation analyses. ResultsPopulations from drier environments exhibited coordinated shifts in life-history strategy, combining faster growth, earlier flowering, and increased reproductive output. These changes were coupled with reduced allocation to roots and structural tissues and diminished investment in traits that buffer plant water status, as reflected in declines in relative water content and higher (less negative) leaf water potentials. Ordinal modeling further indicated that populations from drier environments had a greater probability of severe wilting under drought stress. Together, these patterns are consistent with a drought escape strategy rather than drought avoidance or drought tolerance. ConclusionOur results suggest that increasing aridity can favor integrated drought escape strategies characterized by rapid growth and early reproduction. These coordinated shifts reveal trade-offs between fast life-history strategies and investment in traits associated with drought resistance, highlighting how environmental gradients shape adaptive trait syndromes in wild plant populations.

Background and AimsGroundwater-dependent ecosystems support disproportionate biodiversity in arid regions, yet the population genetics of spring-specialist plants remains poorly understood. Here, we present the first species-wide genetic dataset for crimson monkeyflower ( Mimulus verbenaceus, Phrymaceae), a spring-specialist plant distributed in seeps, springs, and associated riparian areas across desert regions of North America. MethodsUsing genome-wide reduced representation sequencing data consisting of 10,760 SNPs from 175 individuals across 17 populations, we characterized the patterns of genetic diversity using FST and Neis D. Population structure was assessed using ADMIXTURE and PCA. We examined the contributions of climate to range-wide genetic variation in crimson monkeyflower using redundancy analysis. Key ResultsPatterns of genetic differentiation were more consistent with those of spring-specialist animal taxa than those of upland plants or generalist riparian plants. We found strong population structure at both broad regional scales and at fine local scales. While riparian connectivity influenced local patterns of diversity, adaptation to local climatic variation was more influential at regional scales, with temperature, relative humidity, and a monsoon-driven climate gradient structuring genetic differentiation. ConclusionsOur findings highlight the distinctive influence of isolated perennial groundwater sources, as well as adaptation to climate, in shaping genetic variation in this spring-specialist plant. These findings suggest that spring-specialist plants deserve special consideration in ecological theory, management, and conservation.

O_LIIntraspecific variability in hydraulic and morphological traits may alter projections of forest vulnerability to climate change. Recognizing multiscale nature is essential, as trait relationships within populations may not reflect those across the species range. C_LIO_LIWe assessed variability in 11 traits in 10 natural populations of Abies alba across environmental and phylogeographic gradients to evaluate potential impacts on drought vulnerability. We quantified trait variation within and among populations, tested effects of climate, phylogeny and local factors, and evaluated trait coordination across scales. C_LIO_LIHydraulic safety traits and wood density showed low variability, indicating strong constraints. In contrast, water-use and efficiency traits were highly variable. Aridity influenced several traits, but reduced variance was detected only for leaf residual conductance and succulence consisted with stabilising selection. Trait coordination was weak within populations than among populations. C_LIO_LIOverall, A. alba combines constrained hydraulic safety traits with variable water use traits. This may buffer drought impacts but limits shifts in hydraulic safety margins, potentially increasing risks of hydraulic failure, especially in humid environments where populations lack the capacity to tolerate prolonged dry periods. Thus, our findings highlight the need to account for scale-dependent trait variability, coordination, and their underlying drivers when predicting species adaptive capacity to drought. C_LI

The tribe Spermacoceae (Rubiaceae) comprises a morphologically diverse assemblage of approximately 1,400 species distributed across the Neotropics, Africa, Asia, Australia, and Pacific region. It remains one of the most taxonomically intractable groups in the family, with generic limits repeatedly redefined for more than two centuries. Previous phylogenetic studies based on a limited number of plastid and nuclear markers left numerous relationships unresolved and provided sparse representation of Neotropical lineages. Here, we present the first phylogenomic study of the tribe based on plastome-scale data and expanded sampling of Neotropical taxa. We sampled 121 species representing 55 genera spanning all major clades and generated 123 new plastomes, including 25 species incorporated into a molecular phylogenetic framework for the first time. Maximum-likelihood and Bayesian analyses recovered a highly resolved and strongly supported phylogeny, with uncertainty restricted to a small number of deep backbone nodes. Pollen and seed micromorphology provided additional evidence for evaluating phylogenetic relationships. The resulting phylogenetic framework clarifies generic boundaries across several problematic lineages and supports multiple taxonomic changes. Pervasive homoplasy in seed and floral characters rendered several traditionally recognized genera non-monophyletic, warranting new combinations, including Edrastima oxycoccoides, Stenotis alexanderae, and S. prostrata, and a reassessment of taxa such as Terrellianthus serpyllaceus and Oldenlandia dusenii. We further identify genera requiring additional study and provide an updated key to the 82 recognized genera of Spermacoceae. Together, these results provide the most robust phylogenetic framework yet available for the tribe and establish a foundation for future systematic, biogeographic, and evolutionary research.

Background and AimsIn the plant kingdom, gene flow occurs through pollen and seed dispersal, shaping both within-population spatial genetic structure and among-population genetic differentiation. Anthropogenic land-use change can affect levels of gene flow by reducing pollinator abundance and altering pollen and seed dispersal pathways. Yet, how environmental features shape gene flow events in common herbaceous plants - a fundamental building block of many ecosystems - remains poorly understood. We address this gap by investigating how environmental context influences population genetic structure at regional and local scales in the red campion (Silene dioica). MethodsBy sampling 1,005 individuals from 29 populations across habitats ranging from semi-natural to strongly human-altered, we assessed whether population size and landscape composition influenced within-population genetic diversity and population genetic differentiation. At the local scale, we examined whether landscape composition affected fine-scale spatial genetic structure and pollen dispersal distances in a subset of six populations representing the two extremes of an anthropogenic gradient. Key ResultsNo effect of either demographic or landscape factors was found on levels of genetic diversity. We detected moderate levels of genetic differentiation among populations that matched an isolation-by-distance pattern, with high levels of population admixture, while landscape composition did not explain variation in population genetic differentiation. At the local scale, five of the six studied populations exhibited significant spatial genetic structuring, indicating distinct neighbourhoods at spatial scales less than 10 m. Paternity analyses based on 4,800 offspring further revealed predominantly short-distance pollen dispersal together with substantial immigration from external sources. Neither fine-scale genetic structure nor pollen dispersal distances differed between habitat types. ConclusionsAltogether, our results demonstrate a multimodal pattern of gene flow and a remarkable resilience of this common herbaceous species to anthropogenic habitat change, as substantial genetic connectivity is maintained despite insect-mediated pollen dispersal and gravity-driven seed dispersal.

O_LIIn fluctuating environments, the kinetics of stomatal opening and closing influence the balance between carbon gain and water loss. Smaller guard cells may respond faster to fluctuating environmental conditions because of their greater surface area for osmolyte flux relative to cell volume. A related hypothesis is that operational stomatal conductance (gop) is often well below its theoretical maximum (gmax) because at this stomatal aperture, guard cell volume is poised to change rapidly with small changes in turgor pressure. C_LIO_LIWe analyzed 2,124 estimates of stomatal closure kinetics in response to an abrupt increase in vapor pressure deficit (VPD) among 29 diverse wild tomato populations in the genus Solanum. C_LIO_LILeaves with small guard cells and a lower gop to gmax ratio (fgmax) closed faster, but explained variation in kinetic parameters at different levels of biological organization. Guard cell size had high phylogenetic heritability and varied relatively little within populations, whereas fgmax varied mostly among individuals and between light intensity treatments. C_LIO_LISmaller stomata can be speedier, but only if stomata are held at an aperture where they are responsive to changing turgor pressure. Selection on stomatal speed may influence not only anatomical traits like guard cell size, but also physiological controls on gop. C_LI

O_LIWhen species hybridize, resistance to introgression is presumably due to selection against hybridizing alleles. While many studies have characterized direct selection at these sites, alleles may resist introgression through correlational selection. Here we investigate the role of direct and correlational selection in reducing introgression at the color locus in Ipomoea cordatotriloba. C_LIO_LIWe used recombinant inbred lines that varied in limb color, flower size and sugar concentration to estimate the fitness advantage of the flower color allele via direct and correlational selection. To assess the effect of correlational selection on fitness, we ask if floral size or nectar sugar concentration is correlated with fecundity in pink- but not white-limbed lines. C_LIO_LIWe find no evidence for direct selection on flower color across four fitness components - germination, survival, fecundity, and siring success. Instead, both flower size and sugar concentration significantly correlate with fecundity in pink, but not white limbed lines. As a result, correlational selection on the color allele opposes introgression when recurrent migration is low (<3%). C_LIO_LIThese results demonstrate that correlational, rather than direct, selection is sufficient to resist introgression via hybridization and suggest that correlational selection is an underexplored mechanism to generate resistance to introgression across multiple loci. C_LI

Understanding how habitat connectivity shapes biodiversity remains a major ecological challenge. In particular, the roles of connectivity and ecological heterogeneity on co-variation in plant species diversity and intraspecific genetic diversity is not understood. We combined species distribution modelling, resistance-to-movement mapping, landscape connectivity analysis and population genomics to investigate diversity patterns in three wet meadow herbs, Scorzonera humilis, Oenanthe peucedanifolia and Lychnis flos-cuculi, and their surrounding plant communities. Genetic diversity patterns differed strongly among co-occurring species. Connectivity metrics explained genetic diversity only in O. peucedanifolia, and environmental drivers of genetic diversity were highly species specific. Importantly, genetic diversity changed with the presence of some species in the community, but it was consistently unrelated to indicators of local plant community diversity. Overall, the processes shaping within-species biodiversity may differ fundamentally from those structuring habitat connectivity and plant species communities, with important implications for conservation.

Background and aimsThis study combines morphological and environmental data to better understand a Brunfelsia (Solanaceae) species complex, aiming to clarify patterns of variation and identify ecological factors that shape morphotype boundaries. Such an approach provides a broader perspective on how organisms respond to environmental gradients and contributes to a more comprehensive understanding of biodiversity. MethodsWe analyzed 273 herbarium specimens for 13 morphological traits using univariate and ordination analyses, namely PCA and CVA. Climatic and edaphic variables were extracted for 147 specimens with georeferenced records. To assess habitat suitability and the ecological niche of each predefined morphotype, niche models under present conditions and niche overlap tests were conducted. A redundancy analysis (RDA) was applied to evaluate how environmental predictors explain variation in vegetative and floral traits. Finally, DAPC was used to estimate membership probabilities based on morphological and environmental data. Key ResultsTwo well-differentiated groups were recovered: the capitata-hydrangeiformis morphotype, allegedly composing a cline, and the ecologically and morphologically distinct "bahia" morphotype. Variation in floral traits was better explained by environmental predictors than variation in vegetative traits; moreover, floral traits were able to delineate morphotypes more robustly when plotted in isolation. However, when analyzing the results of ecological niche overlap, a significant ecological separation of the "bahia" morphotype from the others was observed. Therefore, key morphological characters for the taxonomy of Brunfelsia covary in part with environmental variables. ConclusionsThese findings support the recognition of "bahia" morphotype as a distinct species to be formally described. This integrative approach contributes to understanding diversification processes in biodiversity hotspots and highlights hidden taxonomic diversity within Brunfelsia, where many rare and narrow-endemic taxa lie.

Most plants require animal pollination to reproduce, prompting concern that pollinator declines immediately threaten plant populations. This concern is warranted if pollinator-mediated seed losses cause declines in plant population growth rates ({lambda}). However, demographic trade-offs might reduce the risk of population decline if seed loss improves performance elsewhere in the life cycle. We conducted a multi-year pollination manipulation on four species and measured how demographic vital rates and {lambda} responded. Seed responses did not predict net changes in {lambda}. Reduced pollination decreased seed production, but only caused a net decrease in {lambda} in one species; in the others, improved survival buffered {lambda}. Increased pollination boosted seed production, but at a cost to survival that caused a net reduction in {lambda} in three species. Our results highlight the importance of demographic trade-offs for understanding the impacts of pollinator declines on plant biodiversity and, more broadly, the population-level impacts of changing mutualisms.

The Hesperiine genus Atrytonopsis Godman, 1900, occurs broadly across the American Southwest. Atrytonopsis margarita (Skinner, 1913) and Atrytonopsis python (W. H. Edwards, 1882) have look-alike appearances, concurrent flights, and geographic distributions which converge in New Mexico. Their similar wing markings and intertwined taxonomic history has made it challenging to fully understand the identity and occurrence of each. Burns (2015) revealed differences in genitalia, clarifying that they are distinct species. Genomic DNA analysis of more than 100 specimens now illuminates their genetic uniqueness, phylogenetic relationship, field identification challenges and details of their geographic distributions.