American Journal of Botany

AO_SCPLOWBSTRACTC_SCPLOWMulti-species communities of epiphytic bromeliads are a defining component of Neotropical canopies, yet we have little knowledge of how closely related species differ in the balance struck among vegetative growth, clonal propagation, and sexual reproduction. We compared reproductive output, clonality, and sexual systems in sympatric populations of Catopsis nutans (Sw.) Griseb. and Catopsis sessiliflora (Ruiz & Pav.) Mez occupying citrus groves in central Belize, sampling 235 reproductively mature individuals across 138 host trees in nine groves. Reproductive output, measured as the count of reproductive structures per individual, was modeled with negative binomial generalized linear mixed models that accounted for vegetative size and host tree identity. All sampled C. nutans were hermaphroditic, whereas all C. sessiliflora were unisexual, representing a dioecious population. Reproductive output increased with vegetative size in both species, and the scaling relationship did not differ between them despite their differing sexual systems. After accounting for size, C. sessiliflora produced more reproductive structures and more connected pups than C. nutans, and we found no evidence of a trade-off between clonal and sexual output in both species. Within C. sessiliflora, staminate individuals produced more flowers than pistillate individuals across comparable sizes. Co-occurring Catopsis can differ markedly in baseline reproductive and clonal output while sharing a conserved scaling of output on vegetative size, offering a foundation for further comparisons of sex-specific reproductive allometry in bromeliads.

AO_SCPLOWBSTRACTC_SCPLOWThe breeding systems of most Bromeliaceae have not been tested directly. We characterized the floral biology and breeding systems of two epiphytic, tank-forming bromeliads endemic to the Atlantic Forest of Brazil, Vriesea rafaelii (Tillandsioideae) and Billbergia brasiliensis (Bromelioideae), using controlled self- and cross-pollinations in a greenhouse. Both species were self-compatible. Based on seed-set, the self-compatibility index was 0.59 in V. rafaelii and 0.87 in B. brasiliensis. In B. brasiliensis, selfed flowers produced lighter fruits and lighter seeds than outcrossed flowers, whereas in V. rafaelii fruit and seed mass did not differ between self- and cross-pollinated flowers. A subset of V. rafaelii flowers showed a spatial separation of the anthers and stigma (herkogamy) that prevented autonomous selfing. These results add two species to the small set of bromeliads with experimentally characterized breeding systems and highlight differences in reproductive output with selfing.

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.

Hybridization and introgression are thought to play key roles in the formation of biodiversity. However, detecting gene flow between species and understanding reticulation patterns remain challenging, especially in species-rich lineages with complex evolutionary histories. Adiantum is a large fern genus, and ecological studies in Amazonia have found that species identification is often difficult due to morphological similarity and overlapping characteristics among species. Although several hybrids have been described in tropical America, comprehensive studies investigating genetic exchanges in this genus are still lacking. We used chloroplast and nuclear phylogenomic data to examine evolutionary relationships among tropical American Adiantum species. By combining traditional phylogenetic analyses with advanced bioinformatic methods such as HybSeq-based target capture, reference-guided phasing (HybPhaser), and network-based analyses, we found widespread reticulate evolution involving both recent and ancient hybridization events. These were especially common among those species that have been difficult to delineate morphologically. Our findings indicate that reticulate evolution has played an important role in shaping the diversity of neotropical Adiantum, especially within the tetraphyllum lineage. Such widespread hybridization has no doubt contributed to morphological ambiguity and taxonomic challenges. Our integrated analytical approach provides a first attempt at untangling the reticulate evolutionary history in this group, and future studies with additional sampling can be expected to clarify the evolutionary processes further.

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.

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

Premise of the studyDisentangling ancestry of insular plant lineages is important for resolving their evolutionary histories but often complicated by polyploidy, an overrepresented condition in remote island floras. A phylogenomic approach was used to study the origin of subgenomes of the tetraploid Hawaiian silversword alliance and advance understanding of this major example of adaptive radiation. MethodsSequences from 461 target-capture nuclear loci were phased to subgenomes of the tetraploid silversword alliance (Compositae) using assemblies from diploid North American tarweeds as clade references. Maximum-likelihood and multispecies- coalescent analyses of phased loci were conducted with and without representatives of diploid lineages throughout tribe Madieae. Key resultsAn allopolyploid origin of the silversword alliance was corroborated, with Subgenome-A phased consistently to Anisocarpus madioides and Subgenome-B phased to diploid representatives of each of three other sublineages of the "Madia" lineage. Phylogenomic analyses indicate Anisocarpus madioides is more closely related to Subgenome-A than to other tarweeds, including Anisocarpus scabridus. Subgenome trees for the silversword alliance are highly congruent with each other and with structural genomic differences between lineages. ConclusionsThese results indicate an even closer relationship of the silversword alliance to extant California tarweeds than previously understood. Anisocarpus madioides has chromosomal and ecological traits anticipated in an ancestor of the silversword alliance, with the widest geographic range among perennial tarweeds and sticky bracts completely enveloping fruits. Within the silversword alliance, robust support for four major clades reinforces the phylogenetic value of chromosomal interchanges and taxonomic insights by Asa Gray regarding the enigmatic liana Dubautia latifolia.

Reproductive biology is a key determinant of fitness. State-dependent speciation-extinction methods (SSEs) are often used to associate traits with patterns of diversification. Previously, SSEs have been used within families to investigate the hypothesis that selfing is an evolutionary "dead end." To the best of the authors knowledge, no study has looked across families, which would increase power to more generally test this hypothesis. Here, we examine the impact of 1) mating system and 2) sexual system on diversification across 18 phylogenetically diverse families. We also discuss how more recent advances in SSE models (i.e., "hidden state" and tree-only models) influence our interpretation of these patterns and evaluate how the relationship between mating and sexual systems can be leveraged to gain insight into the impact of reproductive biology on evolutionary outcomes. In this study, we find that the mating system as a trait does not better explain patterns of diversification when compared to null models, but the sexual system often does. We also find family-level heterogeneity in our results, which suggests conclusions drawn from studies on individual families may not be consistent with any broader trend.

Extrafloral nectaries (EFNs) are a widespread plant defense mutualism trait and are highly convergent, appearing in hundreds of plant lineages worldwide. Here we investigate a report of possible EFNs in Erythranthe angulosa, a recently-described California wildflower. We integrate field observations, insect bioassays, an induction experiment, and microscopy to test for signatures of EFN function, finding no evidence that the distinctive axillary swellings produced by E. angulosa function as EFNs. We also uncovered two distinct morphs at the type locality of E. angulosa that diverge in the number of axillary swellings produced, as well as other shoot architecture traits such as stem thickness, leaf size, and branch number. Although the axillary swellings appear to not function as EFNs, they remain a compelling morphological variant within the yellow monkeyflowers that may perform storage or another unknown function.

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.

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.

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.

Root-associated fungal (RAF) communities can influence tree nutrient acquisition and performance, yet their structuring factors and relationship with tree growth remain poorly understood, particularly near environmental treelines. We characterized root-associated fungal (RAF) communities on fine roots of white spruce (Picea glauca [Moench] Voss) in paired forest and treeline plots across two elevational and one moisture-limited treeline ecotones in Alaska. Using ITS2 DNA metabarcoding of fine root tips, we characterized individual RAF community alpha and beta diversity and tree growth based on basal area increment (BAI) over 5-30 years. As a result, sampling site was the strongest predictor of RAF composition, explaining 19.6% of variation, while soil pH explained an additional 11.7%. Treeline effects on RAF communities were weaker and context-dependent, with treeline trees showing distinct community composition in the Alaska Range, lower alpha diversity across all Hill numbers in Interior Alaska, and higher ECM relative abundance in the Brooks Range. RAF composition did not differ between fast- and slow-growing trees within sites. In contrast, alpha diversity was negatively associated with tree growth: OTU richness, Shannon and Inverted Simpson indices significantly predicted BAI over the previous 5, 10 and 15 years, with fast-growing trees supporting less diverse RAF and ECM communities. This relationship was strongest for recent growth and weakened with longer BAI averaging periods. Our results suggest that high growth of mature P. glauca is not necessarily associated with greater RAF or ECM diversity or specific taxa but may instead rely on fewer dominant or functionally effective fungal partners.

Premise of researchIn plant species that depend on pollinators to produce seeds, declines in pollinator populations should strengthen natural selection for floral traits that increase outcross pollen receipt by increasing the probability of pollinator visitation. One such trait is floral longevity, the amount of time that a flower is open and functional. If flowers that are open longer have a higher probability of pollinator visitation and this pollination benefit outweighs the resource cost of maintaining floral tissue, then pollinator decline should strengthen selection for extended floral longevity. MethodologyTo test whether pollinator decline could strengthen selection for extended longevity, we studied the pollinator-dependent species Lobelia siphilitica. We exposed L. siphilitica plants to either an ambient open-pollination treatment or a reduced open-pollination treatment that simulates pollinator decline. Within each pollination treatment, we measured floral longevity and seeds per fruit and used these data to estimate directional selection on longevity. This experiment was repeated twice. Pivotal resultsIn one experiment, there was significant selection within both ambient and reduced pollination treatments for shortened (rather than extended) floral longevity. In the other experiment, selection on floral longevity within both ambient and reduced pollination treatments was not significantly different from zero. ConclusionsWe found no evidence of selection for extended floral longevity, regardless of the pollination environment. These results suggest that pollinator decline will not strengthen selection for extended longevity and thus that pollinator-dependent species such as L. siphilitica may not respond to pollinator decline by evolving extended floral longevity.

SummaryO_LIIn woody perennials, reproductive allocation considered as a fraction of NPP (RA) has been rarely quantified, especially tracked across plant lifetimes, measured in biologically meaningful currencies, and separated from standing biomass. C_LIO_LIWe addressed this gap by measuring dry mass, nitrogen, and phosphorus for every aboveground tissue type for 14 iteroparous perennial shrubs tracked across their full lifetimes, calculating RA using four accounting schemes and three currencies. C_LIO_LIRA was substantially higher by mid-life than typical estimates from ecosystem-scale studies. Distinguishing standing biomass from yearly production further revised RA upwards. Using a nutrient currency (especially P) increased the perceived costs of reproduction. Propagules were highly nutrient-enriched and reproductive accessory costs consumed more nutrients than did the propagules themselves. Considering N and P resorption from senescing leaves and wood shrank the effective vegetative nutrient budget, further concentrating net annual nutrient demand in reproductive tissues. C_LIO_LIOur results highlight high investment in RA for woody perennials, especially using nutrient currencies. Broadly similar allocation patterns were observed across species with different functional traits and lifespans, suggesting generality that may apply across biomes. Widespread underestimation of RA in forest growth models likely overestimates the proportion of NPP available for vegetative growth, leading to substantial errors in predictions. C_LI

The repeated evolution of certain complex traits within a given lineage is compelling and presents an opportunity for understanding selective and genetic features that promote rapid multi-trait adaptation. The North American plant genus Penstemon is one such example, with numerous evolutionary shifts from ancestral bee syndrome to hummingbird syndrome flowers. Here, we traced the evolution of multi-trait floral phenotypes within a focal clade of Penstemon using a new whole genome phylogenomic estimate and found four independent origins of the hummingbird syndrome. We found strong evolutionary convergence in floral traits across these four origins and observed that the hummingbird syndrome assembled rapidly, without leaving a signal of stepwise modification of traits. Patterns of evolutionary correlations among floral traits in bee syndrome Penstemon species likely enable rapid shifts to hummingbird syndrome. Using phylogenomic tests for introgression, we found no evidence that adaptive introgression has fueled the four repeated origins of hummingbird syndrome flowers. Patterns of allele sharing were instead consistent with substantial levels of incomplete lineage sorting, suggesting repeated complex adaptation involves de novo mutation or adaptation from ancestral variation.

PremisePinguicula are carnivorous plants occupying a wide range of habitats, from wetlands to barren rock cliffs, where CAM photosynthesis was recently discovered in several species. This ecological and physiological diversity makes the genus a promising system for exploring the environmental drivers and evolutionary transitions underlying variation in CAM. Here, we present a physiological survey of CAM with a particular focus on the Mexican Clade, which contains the recently identified CAM species. MethodsWe conducted a carbon isotope survey of live and herbarium specimens to identify candidate CAM species. We then measured diurnal gas-exchange patterns and changes in leaf titratable acidity to quantify CAM activity. ResultsPinguicula species exhibited a variety of photosynthetic phenotypes. Pinguicula vulgaris showed no detectable evidence of CAM, whereas P. cyclosecta and P. moranensis demonstrated a C3-CAM physiology with most net assimilation via C3. Pinguicula martinezii also showed the same C3-CAM physiology under well-watered conditions but had strong facultative induction of CAM with drought. Pinguicula agnata displayed net assimilation via CAM. Titratable acidity had a positive correlation with {delta}13C within the species we sampled. ConclusionsOur results support the existence of a CAM physiological continuum within Pinguicula. Notably, closely related species encompass physiologies that span the large variation of CAM. This diversity provides a rare opportunity for future studies to investigate the evolution of CAM in closely related species, including differences and similarities between differing states across the continuum.

Zingiberales includes eight morphologically distinctive families, but its family-level backbone has remained unstable, especially around Musaceae, Heliconiaceae, Lowiaceae, and Strelitziaceae. We analysed 1566 low-copy nuclear genes from 52 samples, representing all eight families and Pontederia crassipes as outgroup. Concatenated maximum likelihood and multispecies coalescent analyses recovered the same backbone: ((Zingiberaceae, Costaceae), (Cannaceae, Marantaceae)) is sister to (Musaceae, (Heliconiaceae, (Lowiaceae, Strelitziaceae))). Penalized-likelihood dating placed the sampled crown group in the Late Cretaceous, with several deep family-level divergences occurring on short internodes. Analysis of 1248 rerooted gene trees showed that conflict is concentrated on these deep branches and in several shallow clades. HyDe tests of empirical and simulated matrices, each including 62,475 triples, did not support widespread ancient hybridization among the major family-level lineages after filtering against the simulated null model. The nuclear data recover a stable Zingiberales backbone, and the long-standing instability of several deep nodes is best explained by rapid early divergence and extensive incomplete lineage sorting.

Polyploidization can profoundly affect plant metabolite biosynthesis, yet its influence on chemodiversity remains poorly understood, despite the central role of chemodiversity in mediating plant interactions with the environment. The coexistence of facultative apomictic and sexual reproductive systems across ploidy levels in Hypericum provides an excellent model for investigating the evolution of chemodiversity following polyploidization. We analyzed ploidy levels and leaf metabolic fingerprints across selected populations of three Hypericum taxa, H. maculatum, H. perforatum subsp. perforatum and H. perforatum subsp. veronense. Polyploidization was common across all three taxa. Leaf metabolic fingerprints were more pronouncedly differentiated by the ploidy level of the mother plant (F0) than that of the offspring (F1). Although unique metabolic features emerged in plants of most ploidy levels, diploid plants exhibited fewer metabolic features than polyploid plants. Higher Shannon diversity, functional Hill diversity, and intensities of features belonging to specific chemical families were associated with higher F0 ploidy levels in H. perforatum subsp. perforatum, but not in H. maculatum and H. perforatum subsp. veronense. Our findings demonstrate that polyploidization can lead to rapid shifts in chemodiversity across generations in Hypericum. The fast divergence in chemodiversity associated with polyploidization in H. perforatum may contribute to its remarkable invasive potential.

Sinia rhodoleuca, the sole species of the monotypic genus Sinia (Ochnaceae), was previously transferred to Sauvagesia based mainly on morphological similarities. However, its phylogenetic position has remained unresolved because molecular data for the species were unavailable. Here, we generated genomic data for Sinia rhodoleuca and reconstructed its phylogenetic position within Sauvagesieae. Our phylogenomic analyses consistently recovered Sinia rhodoleuca as sister to Indosinia, whereas the Neotropical Sauvagesia formed a distantly related lineage, rendering Sauvagesia broadly circumscribed non-monophyletic. Comparative morphological evidence further supports the close relationship between Sinia and Indosinia, particularly in their closely parallel secondary veins, lacerate stipules, and prominent petaloid staminodes, while differences in floral characters support their recognition as distinct genera. We therefore reinstate Sinia as a distinct genus and provide a revised taxonomic treatment of Sinia rhodoleuca. Our study demonstrates how phylogenomic evidence can resolve long-standing taxonomic uncertainties and reveal evolutionary relationships obscured by morphological similarity.