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All flowering plants are now recognized as diploidized paleopolyploids (Jiao et al., 2011; One Thousand Plant Transcriptomes Initiative, 2019), and polyploid species comprise approximately 30% of contemporary plant species (Wood et al., 2009; Barker et al., 2016a). A major implication of these discoveries is that, to appreciate the evolution of plant diversity, we need to understand the fundamental biology of polyploids and diploidization. This need is broadly recognized by our community as there is a continued, growing interest in polyploidy as a research topic. Over the past 25 years, the sequencing and analysis of plant genomes has revolutionized our understanding of the importance of polyploid speciation to the evolution of land plants. [ABSTRACT FROM AUTHOR]

This article discusses the important role that microbes play in plant ecology and evolution. Microbes, which include diverse soil and foliar microbial communities, have a significant impact on various aspects of plant biology. They can influence maternal effects, phenotypic plasticity, and natural selection in plants. Ignoring the presence and effects of microbes can lead to a misunderstanding of plant processes and outcomes. Therefore, it is crucial for plant ecologists and evolutionary biologists to consider the influence of microbial communities in their research to gain a more accurate understanding of plant biology in the natural world. [Extracted from the article]

Decades of empirical research have revealed how the geological history of our planet shaped plant evolution by establishing well‐known patterns (e.g., how mountain uplift resulted in high rates of diversification and replicate radiations in montane plant taxa). This follows a traditional approach where botanical data are interpreted in light of geological events. In this synthesis, I instead describe how by integrating natural history, phylogenetics, and population genetics, botanical research can be applied alongside geology and paleontology to inform our understanding of past geological and climatic processes. This conceptual shift aligns with the goals of the emerging field of geogenomics. In the neotropics, plant geogenomics is a powerful tool for the reciprocal exploration of two long standing questions in biology and geology: how the dynamic landscape of the region came to be and how it shaped the evolution of the richest flora. Current challenges that are specific to analytical approaches for plant geogenomics are discussed. I describe the scale at which various geological questions can be addressed from biological data and what makes some groups of plants excellent model systems for geogenomics research. Although plant geogenomics is discussed with reference to the neotropics, the recommendations given here for approaches to plant geogenomics can and should be expanded to exploring long‐standing questions on how the earth evolved with the use of plant DNA. [ABSTRACT FROM AUTHOR]

The article discusses the relevance of experimental evolution in botanical research. While many researchers in botany acknowledge the importance of evolution in shaping plant traits and interactions, they often assume that ongoing evolutionary change is not fast enough to impact their research. However, recent research shows that evolution can be rapid in some cases, especially when selection is strong and the generation time of the organisms is short. The article argues that researchers should consider the opportunity for addressing real-time evolution in their research and incorporate an evolutionary framework in their experimental design. It also discusses different ways to study real-time evolution in plants, such as comparative approaches, resurrection experiments, and experimental evolution. The article highlights the challenges and advantages of studying real-time evolution in plants and emphasizes the importance of addressing evolutionary questions in plant conservation. It suggests that developing new fast-cycling model plant species could further advance real-time evolution research in botany. [Extracted from the article]

Premise: As part of global change, climate warming and pollinator decline are expected to affect plant phenology and plant–pollinator interactions. This paper aims at characterizing rapid evolution of life history traits and floral traits over two decades in the wild pansy (Viola arvensis), a common weed in agrosystems. Methods: We used a resurrection ecology approach with genotypes sampled in 1991 and 2012 from a population in Burgundy (France). The species has a mixed mating system (hereafter: mixed selfer) and presents a floral polymorphism. To correct for maternal effects, we measured plant traits in the second generation in a common garden (after a refreshing generation) to characterize plant evolution during the two decades. In addition, historical population selfing rates in 1991 and 2012 were inferred from microsatellites markers through heterozygote deficiency and identity disequilibrium. Results: Phenotypic data revealed a significant advance in flowering date, reduced flower sizes and a higher propensity of plants to set seed by autonomous selfing. Moreover, we detected a change in color morph frequency with an increase of the pale morph frequency. In accordance with phenotypic data, the neutral genetic data revealed an increase in historical selfing rates from 0.68 in 1991 to 0.86 in 2012. Conclusions: Taken together, such data suggest that the wild pansy, a mixed selfer, is evolving a selfing syndrome that may be the consequence of reduced pollinator activity in agrosystems. [ABSTRACT FROM AUTHOR]

Premise: It is well‐known that whole genome duplication (WGD) has played a significant role in the evolution of plants. The best‐known phenotypic effect of WGD is the gigas effect, or the enlargement of polyploid plant traits. WGD is often linked with increased weediness, which could be a result of fitness advantages conferred by the gigas effect. As a result, the gigas effect could potentially explain polyploid persistence and abundance. We test whether a gigas effect is present in the polyploid‐rich geophyte Oxalis, at both organ and cellular scales. Methods: We measured traits in conspecific diploid and polyploid accessions of 24 species across the genus. In addition, we measured the same and additional traits in 20 populations of the weedy and highly ploidy‐variable species Oxalis purpurea L., including measures of clonality and selfing as a proxy for weediness. Ploidy level was determined using flow cytometry. Results: We found substantial variation and no consistent ploidy‐related size difference, both between and within species, and across traits. Oxalis purpurea polyploids did, however, produce significantly more underground biomass and more bulbils than diploids, consistent with a potential role of WGD in the weediness of this species. Conclusions: Our results suggest a more nuanced role for the gigas effect, at least in Oxalis. It may be temporary, short‐lived, and inconsistently expressed and retained on evolutionary time scales, but in the short term can contribute to lineage success via increased vegetative reproduction. [ABSTRACT FROM AUTHOR]

Premise: Pollinator sharing of co‐flowering plants may result in interspecific pollen receipt with a fitness cost. However, the underlying factors that determine the effects of heterospecific pollen (HP) are not fully understood. Moreover, the cost of stigma closure induced by HP may be more severe for plants with special touch‐sensitive stigmas than for plants with non‐touch‐sensitive stigmas. Very few studies have assessed HP effects on stigma behavior. Methods: We conducted hand‐pollination experiments with 10 HP donors to estimate HP effects on stigma behavior and stigmatic pollen germination in Campsis radicans (Bignoniaceae) at low and high pollen loads. We assessed the role of phylogenetic distance between donor and recipient, pollen size, and pollen aperture number in mediating HP effects. Additionally, we observed pollen tube growth to determine the conspecific pollen‐tube‐growth advantage. Results: Stigma behavior differed significantly with HP of different species. Pollen load increased, while pollen size decreased, the percentage of permanent closure and stigmatic germination of HP. Stigmatic HP germination increased with increasing aperture number. However, HP effects did not depend on phylogenetic distance. In addition, conspecific pollen had a pollen‐tube‐growth advantage over HP. Conclusions: Our results provide a good basis for understanding the stigma‐pollen recognition process of plant taxa with touch‐sensitive stigmas. We concluded that certain flowering traits drive the HP effects on the post‐pollination period. To better understand the impact of pollinator sharing and interspecific pollen transfer on plant evolution, we highlight the importance of evaluating more factors that determine HP effects at the community level. [ABSTRACT FROM AUTHOR]

Over longer periods of time, aboveground herbivores may stimulate plant compensatory growth to some extent, which can itself promote further herbivory and increase the return of plant litter, in the form of debris or herbivore feces, to the soil. Herbivory, plant evolution, secondary metabolites, soil community, species interactions, biotic interactions, leaf herbivory, plant-soil feedback, root exudates Keywords: biotic interactions; herbivory; leaf herbivory; plant evolution; plant-soil feedback; root exudates; secondary metabolites; soil community; species interactions EN biotic interactions herbivory leaf herbivory plant evolution plant-soil feedback root exudates secondary metabolites soil community species interactions 672 675 4 06/01/22 20220501 NES 220501 "We were men once, though we've become trees." The second has focused on the mechanisms of such interactions and, more specifically, how plant physiological changes, such as plant defence strategies or the production of particular primary and secondary metabolites, mediate above- and belowground interactions between herbivores and higher trophic level organisms (Soler et al., 2005). [Extracted from the article]

Premise: Apomixis and hybridization are two essential and complementary factors in the evolution of plants, including ferns. Hybridization combines characteristics from different species, while apomixis conserves features within a lineage. When combined, these two processes result in apo‐sex hybrids. The conditions leading to the formation of these hybrids are poorly understood in ferns. Methods: We cultivated spores from 66 fern samples (43 apomicts, 7 apo‐sex hybrids, and 16 sexuals), and measured their development in vitro over 16 weeks. We evaluated germination, lateral meristem formation rates, sexual expression, and production of sporophytes and then compared ontogenetic patterns among the three groups. Results: The three examined groups formed antheridia (male gametangia) but differed in overall gametophyte development. Sexual species created archegonia (female, 86% of viable samples), but no sporophytes. Apomicts rarely created nonfunctional archegonia (8%) but usually produced apogamous sporophytes (75%). Surprisingly, apomictic and sexual species showed similar development speed. The sexually reproducing parents of viable studied hybrids formed about twice as many meristic gametophytes as the apomictic parents (39% vs. 20%, respectively). Conclusions: We present the most thorough comparison of gametangial development of sexual and apomictic ferns, to date. Despite expectations, apomictic reproduction might not lead to earlier sporophyte formation. Apomicts produce functional sperm and thus can contribute this type of gamete to their hybrids. The development patterns found in the parents of hybrids indicate a possible increase of hybridization rates by antheridiogens. The apo‐sex hybrids always inherit the apomictic reproductive strategy and are thus capable of self‐perpetuation. [ABSTRACT FROM AUTHOR]

Lau, J. A, and L. G. Bolin. 2024. The tiny drivers behind plant ecology and evolution. American Journal of Botany e16234. https://doi.org/10.1002/ajb2.16324Our original schematic in Figure 1, which described the processes discussed in our article, included a drawing of an epiphytic orchid. Such a plant would not typically grow in soils and would not have the root structure illustrated in the figure. Accordingly, we have replaced the aboveground plant drawing with a more appropriate taxon.1We apologize for this error. [Extracted from the article]

Premise: When divergent lineages come into secondary contact, reproductive isolation may be incomplete, thus providing an opportunity to investigate how speciation is manifested in the genome. The Louisiana Irises (Iris, series Hexagonae) comprise a group of three or more ecologically and reproductively divergent lineages that can produce hybrids where they come into contact. We estimated standing genetic variation to understand the current distribution of population structure in the Louisiana Irises. Methods: We used genotyping‐by‐sequencing techniques to sample the genomes of Louisiana Iris species across their ranges. We sampled 20 populations (n = 632 individuals) across 11,249 loci and used Entropy and PCA models to assess population genetic data. Results: We discovered evidence for interspecific gene flow in parts of the range. Our analysis revealed patterns of population structure at odds with widely accepted nominal taxonomy. We discovered undescribed hybrid populations, designated as belonging to the I. brevicaulis lineage. Iris nelsonii shared significant ancestry with only one of the purported parent species, I. fulva, evidence inconsistent with a hybrid origin. Conclusions: This study provides several key findings important to the investigation of standing genetic variation in the Louisiana Iris species complex. Compared to the other nominal species, I. brevicaulis contains a large amount of genetic diversity. In addition, we discovered a previously unknown hybrid zone between I. brevicaulis and I. hexagona along the Texas coast. Finally, our results do not support the long‐standing hypothesis that I. nelsonii has mixed ancestry from three parental taxa. [ABSTRACT FROM AUTHOR]

Premise: Two Bignoniaceae stems with the distinctive anatomy of a liana are described from the Miocene of South America. They are the first fossil evidence of climbing habit in Bignoniaceae. Methods: The fossil lianas are siliceous permineralizations. Transverse, tangential, and radial thin sections of the woods were prepared for study using standard petrographic techniques and observed under both light and scanning electron microscopy. Results: The stems consist of wood and presumably bark (peripheral tissues). They exhibit phloem wedges, a cambial variant associated with the climbing habit in Bignoniaceae. The wood is diffuse‐porous; solitary and in radial multiples vessels; alternated intervessel pitting; ray‐vessel pitting with distinct borders; simple perforation plates; rays 1–3 seriate, composed of procumbent cells or body ray cells procumbent with one or two‐row of upright or square marginal cells; fibers septate and non‐septate, with simple to minutely bordered pits; axial parenchyma scanty paratracheal, vasicentric, septate; perforated ray cells; prismatic crystals in rays, and rays and fibers irregularly storied. The fossil stems are related to extant Dolichandra unguis‐cati (L.) Miers. Conclusions: The fossils represent a new taxon, Dolichandra pacei sp. nov., which confirms the presence of a neotropical Bignoniaceae liana from the Miocene and provides the first and oldest evidence of the climbing habit in the family. Paleobotanical studies in the Mariño Formation, with the record of Bignoniaceae and Verbenaceae, and phylogenetic and biogeographical studies have great importance to understand plant evolution and diversification in South American Andes. [ABSTRACT FROM AUTHOR]

Consistent with a role in sporophyte maturation and desiccation, a function that is antithetic to that of tracheophyte stomata, hornwort and moss stomata including those of I Funaria i (Fig. In tracheophytes, stomata are found on the surface of leaves; in mosses, stomata, when present, are confined to the solitary spore capsule in the unbranched sporophyte (Paton and Pearce, 1957). This argument is somewhat problematic considering that the bryophyte ancestor likely emerged before the appearance of vascular plants (Wellman et al., 2003) (although there are no fossils of bryophytes in the Rhynie Chert, one of the oldest known macrofossil land plant assemblages), yet did not evolve to fill the ecological niche rapidly occupied by early vascular plants. Keywords: bryophytes; evolution; Polytrichum; PAP; 3'-phosphoadenosine 5'-phosphate; plant height; Sphagnum; stomata EN bryophytes evolution Polytrichum PAP 3'-phosphoadenosine 5'-phosphate plant height Sphagnum stomata 366 371 6 04/02/21 20210301 NES 210301 The greatest cost associated with terrestrial photosynthesis is maintaining hydration in the presence of phenomenal evaporative forces from the atmosphere (Wong et al., 1979). [Extracted from the article]

The phrase "Darwin's abominable mystery" is frequently used with reference to a range of outstanding questions about the evolution of the plant group today known as the angiosperms. Here, I seek to more fully understand what prompted Darwin to coin the phrase in 1879, and the meaning he attached to it, by surveying the systematics, paleobotanical records, and phylogenetic hypotheses of his time. In the light of this historical research, I argue that Darwin was referring to the origin only of a subset of what are today called angiosperms: a (now obsolete) group equivalent to the "dicotyledons" of the Hooker and Bentham system. To Darwin and his contemporaries, the dicotyledons' fossil record began abruptly and with great diversity in the Cretaceous, whereas the gymnosperms and monocotyledons were thought to have fossil records dating back to the Carboniferous or beyond. Based on their morphology, the dicotyledons were widely seen by botanists in Darwin's time (unlike today) as more similar to the gymnosperms than to the monocotyledons. Thus, morphology seemed to point to gymnosperm progenitors of dicotyledons, but this hypothesis made the monocotyledons, given their (at the time) apparently longer fossil record, difficult to place. Darwin had friendly disagreements about the mystery of the dicotyledons' abrupt appearance in the fossil record with others who thought that their evolution must have been more rapid than his own gradualism would allow. But the mystery may have been made "abominable" to him because it was seen by some contemporary paleobotanists, most notably William Carruthers, the Keeper of Botany at the British Museum, as evidence for divine intervention in the history of life. Subsequent developments in plant systematics and paleobotany after 1879 meant that Darwin's letter was widely understood to be referring to the abrupt appearance of all angiosperms when it was published in 1903, a meaning that has been attached to it ever since. [ABSTRACT FROM AUTHOR]

Premise: Despite the fast pace of exploration of the patterns and processes influencing Neotropical plant hyperdiversity, the taxa explored are mostly from large groups that are widely distributed, morphologically diverse, or economically important. Vochysiaceae is an example of an undersampled taxon, providing an excellent system for investigating Neotropical biogeography. We present a phylogenomics‐based hypothesis of species relationships in Vochysiaceae to investigate its evolutionary history through space and time. Methods: We inferred a phylogeny for 122 species from Vochysiaceae and seven other families of Myrtales. Fossils from four myrtalean families were used to estimate the divergence times within Vochysiaceae. Historical biogeography was estimated using ancestral range probabilities and stochastic mapping. Results: Monophyly of all genera was supported except for Qualea, which was split by Ruizterania into two clades. Vochysiaceae originated ~100 mya, splitting into an Afrotropical and a Neotropical lineage ~50 mya, and its ancestral range is in the area currently occupied by the Cerrado. Conclusions: The most recent common ancestor of Vochysiaceae + Myrtaceae had a West Gondwanan distribution, supporting a South American + African ancestral range of Vochysiaceae. On a global scale, geographic range reduction was the principal biogeographic event. At a finer scale, initial range reduction was also important and the Cerrado region was the most ancestral area with multiple colonization events to the Amazon, Central America, and the Atlantic Forest. Colonization events occurred from open areas to forest vegetation, an unusual finding regarding the evolution of plants in the Neotropics. [ABSTRACT FROM AUTHOR]

Premise: Perhaps the most rapid period of vascular plant evolution occurred during the Silurian–Devonian time interval. Yet, few quantitative analyses have established the extent to which anatomical, morphological, or reproductive features contributed to this episode of tracheophyte diversification. Methods: Phylogenetic analyses were performed using a newly revised matrix of 54 characters (with 158 character states) of 37 of the best‐preserved Paleozoic (predominantly Devonian) plants. Equisetum was included to determine whether it aligns with fossil sphenopsids or taxa collectively considered "ferns". The topology of the 54‐character consensus tree was then compared to the topologies generated using only reproductive features (18 characters; 47 character states), only anatomical features (14 characters; 54 character states), only morphological features (22 characters; 57 character states), and the three pairwise combinations (e.g., anatomical and morphological characters). Results: The new 54‐character tree topology continued to identify a trimerophyte‐euphyllophyte clade and a zosterophyllophyte‐lycophyte clade emerging from a Cooksonia‐rhyniophyte plexus. Equisetum aligned with fossil sphenopsids rather than fern‐like fossil taxa. Reproductive characters or anatomical characters analyzed in isolation resulted in nearly complete polytomy. Among the various permutations of the three categories, anatomical and morphological characters when combined provided the best restoration of the 54‐character tree topology. Conclusions: The phylogenetic relationships among the canonical fossil taxa used in this analysis predominantly reflect morphological trends. Reproductive and anatomical features taken in isolation appear to be evolutionarily conservative characters, i.e., natural selection "sees" the external phenotype. [ABSTRACT FROM AUTHOR]

Plant-environment interactions from the lens of plant stress, reproduction, and mutualisms In this issue of I AJB i , the plant-environment interaction is considered from the lens of environmental stressors, mutualisms, and plant reproduction. Plant reproduction is a critical plant life history trait responsible for plant population persistence, and in this section, interactions between plants and their pollinators and the effect of environmental stressors on plant reproduction are highlighted. Finally, Nihranz et al. ([16]) also examine the effects of plant damage on reproduction, using a transgenerational approach in I Solanum carolinense i by looking at the consequences of both maternal plant herbivory and inbreeding on offspring reproduction. [Extracted from the article]

Premise: Phylogenetic trees of bryophytes provide important evolutionary context for land plants. However, published inferences of overall embryophyte relationships vary considerably. We performed phylogenomic analyses of bryophytes and relatives using both mitochondrial and plastid gene sets, and investigated bryophyte plastome evolution. Methods: We employed diverse likelihood‐based analyses to infer large‐scale bryophyte phylogeny for mitochondrial and plastid data sets. We tested for changes in purifying selection in plastid genes of a mycoheterotrophic liverwort (Aneura mirabilis) and a putatively mycoheterotrophic moss (Buxbaumia), and compared 15 bryophyte plastomes for major structural rearrangements. Results: Overall land‐plant relationships conflict across analyses, generally weakly. However, an underlying (unrooted) four‐taxon tree is consistent across most analyses and published studies. Despite gene coverage patchiness, relationships within mosses, liverworts, and hornworts are largely congruent with previous studies, with plastid results generally better supported. Exclusion of RNA edit sites restores cases of unexpected non‐monophyly to monophyly for Takakia and two hornwort genera. Relaxed purifying selection affects multiple plastid genes in mycoheterotrophic Aneura but not Buxbaumia. Plastid genome structure is nearly invariant across bryophytes, but the tufA locus, presumed lost in embryophytes, is unexpectedly retained in several mosses. Conclusions: A common unrooted tree underlies embryophyte phylogeny, [(liverworts, mosses), (hornworts, vascular plants)]; rooting inconsistency across studies likely reflects substantial distance to algal outgroups. Analyses combining genomic and transcriptomic data may be misled locally for heavily RNA‐edited taxa. The Buxbaumia plastome lacks hallmarks of relaxed selection found in mycoheterotrophic Aneura. Autotrophic bryophyte plastomes, including Buxbaumia, hardly vary in overall structure. [ABSTRACT FROM AUTHOR]

Although the number of studies focusing on floral scent is mounting, a large number of these newer studies lack a chemical ecology, evolutionary biology, and pollination focus. Keywords: biosynthesis; biotic interactions; chemical ecology; collaborative research; floral scent; plant evolution; plant volatiles; pollination; secondary metabolites; species interactions EN biosynthesis biotic interactions chemical ecology collaborative research floral scent plant evolution plant volatiles pollination secondary metabolites species interactions 729 731 3 06/05/21 20210501 NES 210501 We have known for millennia that insects can smell and that this sense may play a role in their pollination of flowering plants. The omission of this important trait - despite extensive data showing its importance in plant-animal interactions (Raguso, 2008a, b) - remains a serious deficit in many pollination studies. [Extracted from the article]

Premise: Although hybridization has played an important role in the evolution of many plant species, phylogenetic reconstructions that include hybridizing lineages have been historically constrained by the available models and data. Restriction‐site‐associated DNA sequencing (RADseq) has been a popular sequencing technique for the reconstruction of hybridization in the next‐generation sequencing era. However, the utility of RADseq for the reconstruction of complex evolutionary networks has not been thoroughly investigated. Conflicting phylogenetic relationships in the genus Medicago have been mainly attributed to hybridization, but the specific hybrid origins of taxa have not been yet clarified. Methods: We obtained new molecular data from diploid species of Medicago section Medicago using single‐digest RADseq to reconstruct evolutionary networks from gene trees, an approach that is computationally tractable with data sets that include several species and complex hybridization patterns. Results: Our analyses revealed that assembly filters to exclusively select a small set of loci with high phylogenetic information led to the most‐divergent network topologies. Conversely, alternative clustering thresholds or filters on the number of samples per locus had a lower impact on networks. A strong hybridization signal was detected for M. carstiensis and M. cretacea, while signals were less clear for M. rugosa, M. rhodopea, M. suffruticosa, M. marina, M. scutellata, and M. sativa. Conclusions: Complex network reconstructions from RADseq gene trees were not robust under variations of the assembly parameters and filters. But when the most‐divergent networks were discarded, all remaining analyses consistently supported a hybrid origin for M. carstiensis and M. cretacea. [ABSTRACT FROM AUTHOR]

Premise: Male gametophytes of most seed plants deliver sperm to eggs via a pollen tube. Pollen tube growth rates (PTGRs) of angiosperms are exceptionally rapid, a pattern attributed to more effective haploid selection under stronger pollen competition. Paradoxically, whole genome duplication (WGD) has been common in angiosperms but rare in gymnosperms. Pollen tube polyploidy should initially accelerate PTGR because increased heterozygosity and gene dosage should increase metabolic rates. However, polyploidy should also independently increase tube cell size, causing more work which should decelerate growth. We asked how genome size changes have affected the evolution of seed plant PTGRs. Methods: We assembled a phylogenetic tree of 451 species with known PTGRs. We then used comparative phylogenetic methods to detect effects of neo‐polyploidy (within‐genus origins), DNA content, and WGD history on PTGR, and correlated evolution of PTGR and DNA content. Results: Gymnosperms had significantly higher DNA content and slower PTGR optima than angiosperms, and their PTGR and DNA content were negatively correlated. For angiosperms, 89% of model weight favored Ornstein‐Uhlenbeck models with a faster PTGR optimum for neo‐polyploids, whereas PTGR and DNA content were not correlated. For within‐genus and intraspecific‐cytotype pairs, PTGRs of neo‐polyploids < paleo‐polyploids. Conclusions: Genome size increases should negatively affect PTGR when genetic consequences of WGDs are minimized, as found in intra‐specific autopolyploids (low heterosis) and gymnosperms (few WGDs). But in angiosperms, the higher PTGR optimum of neo‐polyploids and non‐negative PTGR‐DNA content correlation suggest that recurrent WGDs have caused substantial PTGR evolution in a non‐haploid state. [ABSTRACT FROM AUTHOR]

Premise: In plant groups with limited intrinsic barriers to gene flow, it is thought that environmental conditions can modulate interspecific genetic exchange. Oaks are known for limited barriers to gene flow among closely related species. Here, we use Quercus as a living laboratory in which to pursue a fundamental question in plant evolution: Do environmental gradients restrict or promote genetic exchange between species? Methods: We focused on two North American oaks, the rare Quercus dumosa and the widespread Q. berberidifolia. We sampled intensively along a contact zone in California, USA. We sequenced restriction site‐associated DNA markers and measured vegetative phenotype. We tested for genetic exchange, the association with climate, and the effect on phenotype. Results: There is evidence for genetic exchange between the species. Admixed plants are found in areas of intermediate climate, while less admixed plants are found at the extremes of the climatic gradient. Genetic and phenotypic patterns are out of phase in the contact zone; some plants display the phenotype of one species but are genetically associated with another. Conclusions: Our results support the hypothesis that a strong climatic gradient can promote genetic exchange between species. The overall weak correlation between genotype and phenotype in the contact zone between the species suggests that genetic exchange can lead to the breakdown of trait combinations used to define species. This incongruency predicts ongoing problems for conservation of Q. dumosa, with implications for conservation of other oaks. [ABSTRACT FROM AUTHOR]

Premise of the Study: Conifers are an important living seed plant lineage with an extensive fossil record spanning more than 300 million years. The group therefore provides an excellent opportunity to explore congruence and conflict between dated molecular phylogenies and the fossil record. Methods: We surveyed the current state of knowledge in conifer phylogenetics to present a new time‐calibrated molecular tree that samples ~90% of extant species diversity. We compared phylogenetic relationships and estimated divergence ages in this new phylogeny with the paleobotanical record, focusing on clades that are species‐rich and well known from fossils. Key Results: Molecular topologies and estimated divergence ages largely agree with the fossil record in Cupressaceae, conflict with it in Araucariaceae, and are ambiguous in Pinaceae and Podocarpaceae. Molecular phylogenies provide insights into some fundamental questions in conifer evolution, such as the origin of their seed cones, but using them to reconstruct the evolutionary history of specific traits can be challenging. Conclusions: Molecular phylogenies are useful for answering deep questions in conifer evolution if they depend on understanding relationships among extant lineages. Because of extinction, however, molecular datasets poorly sample diversity from periods much earlier than the Late Cretaceous. This fundamentally limits their utility for understanding deep patterns of character evolution and resolving the overall pattern of conifer phylogeny. [ABSTRACT FROM AUTHOR]

Premise of the Study: The evolution of full mycoheterotrophy is one of the most interesting topics within plant evolution. The leafless orchid Cymbidium macrorhizon is often assumed to be fully mycoheterotrophic even though it has a green stem and fruit capsule. Here, we assessed the trophic status of this species by analyzing the chlorophyll content and the natural 13C and 15N abundance in the sprouting and the fruiting season. Methods: The chlorophyll content was measured in five sprouting and five fruiting individuals of C. macrorhizon that were co‐occurring. In addition, their 13C and 15N isotopic signatures were compared with those of neighboring autotrophic and partially mycoheterotrophic reference plants. Key Results: Fruiting individuals of C. macrorhizon were found to contain a remarkable amount of chlorophyll compared to their sprouting counterparts. In addition, the natural abundance of 13C in the tissues of the fruiting plants was slightly depleted relative to the sprouting ones. Linear two‐source mixing model analysis revealed that fruiting C. macrorhizon plants obtained approximately 73.7 ± 2.0% of their total carbon from their mycorrhizal fungi when the sprouting individuals were used as the 100% carbon gain standard. Conclusions: Our results indicated that despite its leafless status, fruiting plants of C. macrorhizon were capable of fixing significant quantities of carbon. Considering the autotrophic carbon gain increases during the fruiting season, its photosynthetic ability may contribute to fruit and seed production. These results indicate that C. macrorhizon should, therefore, be considered a partially mycoheterotrophic species rather than fully mycoheterotrophic, at least during the fruiting stage. [ABSTRACT FROM AUTHOR]

Premise of the Study: Equisetum is the sole living representative of Sphenopsida, a clade with impressive species richness, a long fossil history dating back to the Devonian, and obscure relationships with other living pteridophytes. Based on molecular data, the crown group age of Equisetum is mid‐Paleogene, although fossils with possible crown synapomorphies appear in the Triassic. The most widely circulated hypothesis states that the lineage of Equisetum derives from calamitaceans, but no comprehensive phylogenetic studies support the claim. Using a combined approach, we provide a comprehensive phylogenetic analysis of Equisetales, with special emphasis on the origin of genus Equisetum. Methods: We performed parsimony phylogenetic analyses to address relationships of 43 equisetalean species (15 extant, 28 extinct) using a combination of morphological and molecular characters. Key Results: We recovered Equisetaceae + Neocalamites as sister to Calamitaceae + a clade of Angaran and Gondwanan horsetails, with the four groups forming a clade that is sister to Archaeocalamitaceae. The estimated age for the Equisetum crown group is mid‐Mesozoic. Conclusions: Modern horsetails are not nested within calamitaceans; instead, both groups have explored independent evolutionary trajectories since the Carboniferous. Diverse fossil taxon sampling helps to shed light on the position and relationships of equisetalean lineages, of which only a tiny remnant is present within the extant flora. Understanding these relationships and early character configurations of ancient plant clades as Equisetales provide useful tests of hypotheses about overall phylogenetic relationships of euphyllophytes and foundations for future tests of molecular dates with paleontological data. [ABSTRACT FROM AUTHOR]

Premise of the Study: Inclusion of fossils in phylogenetic analyses is necessary in order to construct a comprehensive “tree of death” and elucidate evolutionary history of taxa; however, such incorporation of fossils in phylogenetic reconstruction is dependent on the availability and interpretation of extensive morphological data. Here, the Zingiberales, whose familial relationships have been difficult to resolve with high support, are used as a case study to illustrate the importance of including fossil taxa in systematic studies. Methods: Eight fossil taxa and 43 extant Zingiberales were coded for 39 morphological seed characters, and these data were concatenated with previously published molecular sequence data for analysis in the program MrBayes. Key Results: Ensete oregonense is confirmed to be part of Musaceae, and the other seven fossils group with Zingiberaceae. There is strong support for Spirematospermum friedrichii, Spirematospermum sp. ‘Goth’, S. wetzleri, and Striatornata sanantoniensis in crown Zingiberaceae while “Musa” cardiosperma, Spirematospermum chandlerae, and Tricostatocarpon silvapinedae are best considered stem Zingiberaceae. Inclusion of fossils explains how different topologies from morphological and molecular data sets is due to shared plesiomorphic characters shared by Musaceae, Zingiberaceae, and Costaceae, and most of the fossils. Conclusions: Inclusion of eight fossil taxa expands the Zingiberales tree and helps explain the difficulty in resolving relationships. Inclusion of fossils was possible in part due to a large morphological data set built using nondestructive microcomputed tomography data. Collaboration between paleo‐ and neobotanists and technology such as microcomputed tomography will help to build the tree of death and ultimately improve our understanding of the evolutionary history of monocots. [ABSTRACT FROM AUTHOR]

Premise of the Study: We provide the largest phylogenetic analyses to date of Apocynaceae in terms of taxa and molecular data as a framework for analyzing the evolution of vegetative and reproductive traits. Methods: We produced maximum‐likelihood phylogenies of Apocynaceae using 21 plastid loci sampled from 1045 species (nearly 25% of the family) and complete plastomes from 73 species. We reconstructed ancestral states and used model comparisons in a likelihood framework to analyze character evolution across Apocynaceae. Key Results: We obtained a well‐supported phylogeny of Apocynaceae, resolving poorly understood tribal and subtribal relationships (e.g., among Amsonieae and Hunterieae, within Asclepiadeae), rejecting monophyly of Melodineae and Odontadenieae, and placing previously unsampled and enigmatic taxa (e.g., Pycnobotrya). We provide new insights into the evolution of Apocynaceae, including frequent shifts between herbaceousness and woodiness, reversibility of twining, integrated evolution of the corolla and gynostegium, and ancestral baccate fruits. Conclusions: Increased sampling and selection of best‐fitting models of evolution provide more resolved and robust estimates of phylogeny and character evolution than obtained in previous studies. Evolutionary inferences are sensitive to choice of phylogenetic frameworks and models. [ABSTRACT FROM AUTHOR]

Premise of the Study: For the past one billion years, green plants (Viridiplantae) have dominated global ecosystems, yet many key branches in their evolutionary history remain poorly resolved. Using the largest analysis of Viridiplantae based on plastid genome sequences to date, we examined the phylogeny and implications for morphological evolution at key nodes. Methods: We analyzed amino acid sequences from protein‐coding genes from complete (or nearly complete) plastomes for 1879 taxa, including representatives across all major clades of Viridiplantae. Much of the data used was derived from transcriptomes from the One Thousand Plants Project (1KP); other data were taken from GenBank. Key Results: Our results largely agree with previous plastid‐based analyses. Noteworthy results include (1) the position of Zygnematophyceae as sister to land plants (Embryophyta), (2) a bryophyte clade (hornworts, mosses + liverworts), (3) Equisetum + Psilotaceae as sister to Marattiales + leptosporangiate ferns, (4) cycads + Ginkgo as sister to the remaining extant gymnosperms, within which Gnetophyta are placed within conifers as sister to non‐Pinaceae (Gne‐Cup hypothesis), and (5) Amborella, followed by water lilies (Nymphaeales), as successive sisters to all other extant angiosperms. Within angiosperms, there is support for Mesangiospermae, a clade that comprises magnoliids, Chloranthales, monocots, Ceratophyllum, and eudicots. The placements of Ceratophyllum and Dilleniaceae remain problematic. Within Pentapetalae, two major clades (superasterids and superrosids) are recovered. Conclusions: This plastid data set provides an important resource for elucidating morphological evolution, dating divergence times in Viridiplantae, comparisons with emerging nuclear phylogenies, and analyses of molecular evolutionary patterns and dynamics of the plastid genome. [ABSTRACT FROM AUTHOR]

PREMISE OF THE STUDY: Grapes are one of the most economically important berry crops worldwide, with the vast majority of production derived from the domesticated Eurasian species Vitis vinifera. Expansion of production into new areas, development of new cultivars, and concerns about adapting grapevines for changing climates necessitate the use of wild grapevine species in breeding programs. Diversity within Vitis has long been a topic of study; however, questions remain regarding relationships between species. Furthermore, the identity of some living accessions is unclear. METHODS: This study generated 11,020 single nucleotide polymorphism (SNP) markers for more than 300 accessions in the USDA-ARS grape germplasm repository using genotyping-by- sequencing. Resulting data sets were used to reconstruct evolutionary relationships among several North American and Eurasian Vitis species, and to suggest taxonomic labels for previously unidentified and misidentified germplasm accessions based on genetic distance. KEY RESULTS: Maximum likelihood analyses of SNP data support the monophyly of Vitis, subg. Vitis, a Eurasian subg. Vitis clade, and a North American subg. Vitis clade. Data delineate species groups within North America. In addition, analysis of genetic distance suggested taxonomic identities for 20 previously unidentified Vitis accessions and for 28 putatively misidentified accessions. CONCLUSIONS: This work advances understanding of Vitis evolutionary relationships and provides the foundation for ongoing germplasm enhancement. It supports conservation and breeding efforts by contributing to a growing genetic framework for identifying novel genetic variation and for incorporating new, unsampled populations into the germplasm repository system. [ABSTRACT FROM AUTHOR]

PREMISE OF THE STUDY: Inferring the evolution of characters in Isoëtes has been problematic, as these plants are morphologically conservative and yet highly variable and homoplasious within that conserved base morphology. However, molecular phylogenies have given us a valuable tool for testing hypotheses of character evolution within the genus, such as the hypothesis of ongoing morphological reductions. METHODS: We examined the reduction in lobe number on the underground trunk, or corm, by combining the most recent molecular phylogeny with morphological descriptions gathered from the literature and observations of living specimens. Ancestral character states were inferred using nonstationary evolutionary models, reversible-jump MCMC and Bayesian model averaging. KEY RESULTS: Our results support the hypothesis of a directional reduction in lobe number in Isoëtes, with the best-supported model of character evolution being one of irreversible reduction. Furthermore, the most probable ancestral corm lobe number of extant Isoëtes is three, and a reduction to two lobes has occurred at least six times. CONCLUSIONS: From our results, we can infer that corm lobation, like many other traits in Isoëtes, shows a degree of homoplasy, and yet also shows ongoing evolutionary reduction. [ABSTRACT FROM AUTHOR]

PREMISE OF THE STUDY:: Autopolyploidy, or whole‐genome duplication, is a recurrent phenomenon in plant evolution. Its existence can be inferred from the presence of massive levels of genetic redundancy revealed by comparative plant phylogenomics. Whole‐genome duplication is theoretically associated with evolutionary novelties such as the development of new metabolic reactions and therefore contributes to the evolution of new plant metabolic profiles. However, very little is yet known about the impact of autopolyploidy on the metabolism of recently formed autopolyploids. This study provides a better understanding of the relevance of this evolutionary process. METHODS:: In this study, we compared the metabolic profiles of wild diploids, wild autotetraploids, and artificial autotetraploids of Arabidopsis thaliana using targeted ultra‐high performance liquid chromatography‐triple quadrupole‐ mass spectrometry (UPLC‐QqQ‐MS) metabolomics. KEY RESULTS:: We found that wild and artificial A. thaliana autotetraploids display different metabolic profiles. Furthermore, wild autotetraploids display unique metabolic profiles associated with their geographic origin. CONCLUSIONS:: Autopolyploidy might help plants adapt to challenging environmental conditions by allowing the evolution of novel metabolic profiles not present in the parental diploids. We elaborate on the causes and consequences leading to these distinct profiles. [ABSTRACT FROM AUTHOR]

An essay is presented on the impact of dispersal on habitat adaptation of plants and mentions the importance of studying plant to analyze evolutionary feedback loop's nature between the two events.

PREMISE OF THE STUDY: Hybridization between diploids and tetraploids can lead to new allopolyploid species, often via a triploid intermediate. Viable triploids are often produced asymmetrically, with greater success observed for "maternal-excess" crosses where the mother has a higher ploidy than the father. Here we investigated the evolutionary origins of Mimulus peregrinus, an allohexaploid recently derived from the triploid M. ?robertsii, to determine whether reproductive asymmetry has shaped the formation of this new species. METHODS: We used reciprocal crosses between the diploid (M. guttatus) and tetraploid (M. luteus) progenitors to determine the viability of triploid M. ?robertsii hybrids resulting from paternal- vs. maternal-excess crosses. To investigate whether experimental results predict patterns seen in the field, we performed parentage analyses comparing natural populations of M. peregrinus to its diploid, tetraploid, and triploid progenitors. Organellar sequences obtained from pre-existing genomic data, supplemented with additional genotyping was used to establish the maternal ancestry of multiple M. peregrinus and M. ?robertsii populations. KEY RESULTS: We found strong evidence for asymmetric origins of M. peregrinus, but opposite to the common pattern, with paternal-excess crosses significantly more successful than maternal-excess crosses. These results successfully predicted hybrid formation in nature: 111 of 114 M. ?robertsii individuals, and 27 of 27 M. peregrinus, had an M. guttatus maternal haplotype. CONCLUSION: This study, which includes the first Mimulus chloroplast genome assembly, demonstrates the utility of parentage analysis through genome skimming. We highlight the benefits of complementing genomic analyses with experimental approaches to understand asymmetry in allopolyploid speciation. [ABSTRACT FROM AUTHOR]

PREMISE OF THE STUDY: After decades of interest, the contribution of hybridization to ecological diversification remains unclear. Hybridization is a potent source of novelty, but nascent hybrid lineages must overcome reproductive and ecological competition from their parental species. Here, we assess whether hybrid speciation is advantageous over alternative modes of speciation, by comparing the geographical and ecological ranges and climatic niche evolutionary rates of stabilized allopolyploid vs. autopolyploids in the Alyssum montanum species complex. METHODS: We combined an extensive review of studies addressing the systematics and genetic diversity of A. montanum s.l., with flow cytometry and cloning of nuclear markers, to establish the ploidy level and putative hybrid nature of 205 populations. The respective geographic distribution and climatic niche evolution dynamics of the allo- and autopolyploids were investigated using multivariate analyses and comparative phylogenetic approaches. KEY RESULTS: As expected by theory, allopolyploids occur mainly along contact zones and are generally spatially overlapping with their diploid counterparts. However, they demonstrate higher rates of niche evolution and expand into different climatic conditions than those of their diploid congeners. In contrast, autopolyploids show lower rates of niche evolution, occupy ecological niches similar to their ancestors and are restricted to less competitive and peripheral geographic areas. CONCLUSIONS: Hybridization thus seems advantageous by promoting ecological niche evolution and more readily allowing escape from competitive exclusion. [ABSTRACT FROM AUTHOR]

Polyploidy is a common mode of speciation that can have far-reaching consequences for plant ecology and evolution. Because polyploidy can induce an array of phenotypic changes, there can be cascading effects on interactions with other species. These interactions, in turn, can have reciprocal effects on polyploid plants, potentially impacting their establishment and persistence. Although there is a wealth of information on the genetic and phenotypic effects of polyploidy, the study of species interactions in polyploid plants remains a comparatively young field. Here we reviewed the available evidence for how polyploidy may impact many types of species interactions that range from mutualism to antagonism. Specifically, we focused on three main questions: (1) Does polyploidy directly cause the formation of novel interactions not experienced by diploids, or does it create an opportunity for natural selection to then form novel interactions? (2) Does polyploidy cause consistent, predictable changes in species interactions vs. the evolution of idiosyncratic differences? (3) Does polyploidy lead to greater evolvability in species interactions? From the scarce evidence available, we found that novel interactions are rare but that polyploidy can induce changes in pollinator, herbivore, and pathogen interactions. Although further tests are needed, it is likely that selection following whole-genome duplication is important in all types of species interaction and that there are circumstances in which polyploidy can enhance the evolvability of interactions with other species. [ABSTRACT FROM AUTHOR]

PREMISE OF THE STUDY: Like many other flowering plants, members of the Compositae (Asteraceae) have a polyploid ancestry. Previous analyses found evidence for an ancient duplication or possibly triplication in the early evolutionary history of the family. We sought to better place this paleopolyploidy in the phylogeny and assess its nature. METHODS: We sequenced new transcriptomes for Barnadesia, the lineage sister to all other Compositae, and four representatives of closely related families. Using a recently developed algorithm, MAPS, we analyzed nuclear gene family phylogenies for evidence of paleopolyploidy. KEY RESULTS:We found that the previously recognized Compositae paleopolyploidy is also in the ancestry of the Calyceraceae. Our phylogenomic analyses uncovered evidence for a successive second round of genome duplication among all sampled Compositae except Barnadesia. CONCLUSIONS: Our analyses of new samples with new tools provide a revised view of paleopolyploidy in the Compositae. Together with results from a high density Lactuca linkage map, our results suggest that the Compositae and Calyceraceae have a common paleotetraploid ancestor and that most Compositae are descendants of a paleohexaploid. Although paleohexaploids have been previously identified, this is the first example where the paleotetraploid and paleohexaploid lineages have survived over tens of millions of years. The complex polyploidy in the ancestry of the Compositae and Calyceraceae represents a unique opportunity to study the long-term evolutionary fates and consequences of different ploidal levels. [ABSTRACT FROM AUTHOR]

PREMISE OF THE STUDY: Despite being highly fertile and occupying a large geographic region, the North American heartleaf bittercress (Cardamine cordifolia; Brassicaceae) has a puzzling triploid-like chromosome number (2n = 3x = 24). As most triploids are sterile, we embarked on a detailed analysis of the C. cordifolia genome to elucidate its origin and structure. METHODS: Mitotic and meiotic chromosome complement of C. cordifolia was analyzed by comparative chromosome painting using chromosome-specific BAC contigs of Arabidopsis thaliana. Resulting chromosome patterns were documented by multicolor fluorescence microscopy and compared with known ancestral and extant Brassicaceae genomes. KEY RESULTS:We discovered that C. cordifolia is not a triploid hybrid but a diploidized tetraploid with the prevalence of regular, diploid-like meiotic pairing. The ancestral tetraploid chromosome number (2n = 32) was reduced to a triploid-like number (2n = 24) through four terminal chromosome translocations. CONCLUSIONS: The structure of the pseudotriploid C. cordifolia genome results from a stepwise diploidization process after whole-genome duplication. We showed that translocation-based descending dysploidy (from n = 16 to n = 12) was mediated by the formation of five new chromosomes. The genome of C. cordifolia represents the diploidization process in statu nascendi and provides valuable insights into mechanisms of postpolyploidy rediploidization in land plants. Our data further suggest that chromosome number alone does not need to be a reliable proxy of species' evolutionary past and that the same chromosome number may originate either by polyploidization (hybridization) or due to descending dysploidy. [ABSTRACT FROM AUTHOR]

How did plant species emerge from their most recent common ancestors (MRCAs) 250 million years ago? Modern plant genomes help to address such key questions in unveiling precise species genealogies. The field of paleogenomics is undergoing a paradigm shift for investigating species evolution from the study of ancestral genomes from extinct species to deciphering the evolutionary forces (in terms of duplication, fusion, fission, deletion, and translocation) that drove present-day plant diversity (in terms of chromosome/gene number and genome size). In this review, inferred ancestral karyotype genomes are shown to be powerful tools to (1) unravel the past history of extant species by recovering the variations of ancestral genomic compartments and (2) accelerate translational research by facilitating the transfer of genomic information from model systems to species of agronomic interest. [ABSTRACT FROM AUTHOR]

PREMISE OF THE STUDY: Evolutionary radiations provide opportunities to examine large-scale patterns in diversification and character evolution, yet are often recalcitrant to phylogenetic resolution due to rapid speciation events. The plant genus Penstemon has been difficult to resolve using Sanger sequence-based markers, leading to the hypothesis that it represents a recent North American radiation. The current study demonstrates the utility of multiplexed shotgun genotyping (MSG), a style of restriction site-associated DNA sequencing (RADseq), to infer phylogenetic relationships within a subset of species in this genus and provide insight into evolutionary patterns. METHODS: We sampled genomic DNA, primarily from herbarium material, and subjected it to MSG library preparation and lllumina sequencing. The resultant sequencing reads were clustered into homologous loci, aligned, and concatenated into data matrices that differed according to clustering similarity and amount of missing data. We performed phylogenetic analyses on these matrices using maximum likelihood (RAxML) and a species tree approach (SVDquartets). KEY RESULTS: MSG data provide a highly resolved estimate of species relationships within Penstemon. While most species relationships were highly supported, the position of certain taxa remains ambiguous, suggesting that increased taxonomic sampling or additional methodologies may be required. The data confirm that evolutionary shifts from hymenopteran- to hummingbird-adapted flowers have occurred independently many times. CONCLUSIONS: This study demonstrates that phylogenomic approaches yielding thousands of variable sites can greatly improve species-level resolution of recent and rapid radiations. Similar to other studies, we found that less conservative similarity and missing data thresholds resulted in more highly supported topologies. [ABSTRACT FROM AUTHOR]

PREMISE OF THE STUDY: Genetic data suggest that three lineages of Phragmites australis are found in North America: the Native North American lineage, the Gulf Coast lineage, and the Invasive lineage. In Mexico, P. australis is a common species, but nothing is known about the distribution or ecology of these lineages. We examined the phylogeography of P. australis to analyze the current geographic distribution of genetic variation, demographic history, and dispersal patterns to better understand its evolutionary history in Mexico. METHODS: We sampled 427 individuals from 28 populations. We used two noncoding regions of chloroplast DNA to estimate the levels of genetic variation and identified the genetic groups across the species' geographical range in Mexico. We compared the genealogical relationships among haplotypes with those previously reported. A hypothesis of demographic expansion was also tested for the Mexican P. australis lineages. KEY RESULTS: We found 13 new haplotypes native to Mexico that might be undergoing an active process of expansion and diversification. Genealogical analyses provided evidence that two independent lineages of P. australis are present in Mexico. The invasive lineage was not detected with our sampling. Our estimates of population expansions in Mexico ranged from 0.202 to 0.726 mya. CONCLUSIONS: Phragmites australis is a native species that has been in Mexico for thousands of years. Genetic data suggest that climatic changes during the Pleistocene played an important role in the demographic expansion of the populations that constitute the different genetic groups of P. australis in Mexico. [ABSTRACT FROM AUTHOR]

PREMISE OF THE STUDY: Although much attention has focused on the diversity of plant mating systems, only a few studies have considered the joint effects of mating system and sexual conflict in plant evolution. In mixed-mating Collinsia heterophylla, a sexual conflict over timing of stigma receptivity is proposed: pollen with a capacity to induce early onset of stigma receptivity secures paternity for early-arriving pollen (at the expense of reduced maternal seed set), whereas late onset of stigma receptivity mitigates the negative effects of early-arriving pollen. Here we investigated whether selection on pollen and pistil traits involved in sexual conflict is affected by the presence of both outcross- and self-pollen (mixed mating) during pollen competition. METHODS: We conducted two-donor crosses at different floral developmental stages to explore male fitness (siring ability) and female fitness (seed set) in relation to male and female identity, pollen and pistil traits, and type of competitor pollen (outcross vs. self). KEY RESULTS: Lite fertilizing pollen rather Than rapidly growing pollen tubes was most successful in terms of siring surreys, especially in competition with Self-pgllen after pollination dt early floral stages. Late stiqma receptivity increased seed act after early-stage pollinations, in agreement with selection against antagonistic pollen. CONCLUSIONS: flection on pollen and pistil truiti in C. heterophylla is affected by both sexual conflict and mixed moling, suggesting The Important of jointly considering these factors in plant evolution. [ABSTRACT FROM AUTHOR]

PREMISE OF THE STUDY: Project Baseline is a seed bank that offers an unprecedented opportunity to examine spatial and temporal dimensions of micro-evolution during an era of rapid environmental change. Over the upcoming 50 years, biologists will withdraw genetically representative samples of past populations from this time capsule of seeds and grow them contemporaneously with modern samples to detect any phenotypic and molecular evolution that has occurred during the intervening time. METHODS: We carefully developed this living genome bank using protocols to enhance its experimental value by collecting from multiple populations and species across a broad geographical range in sites that are likely to be preserved into the future. Seeds are accessioned with site and population data and are stored by maternal line under conditions that maximize seed longevity. This open-access resource will be available to researchers at regular intervals to evaluate contemporary evolution. KEY RESULTS: To date, the Project Baseline collection includes 100-200 maternal lines of each of 61 species collected from over 831 populations on sites that are likely to be preserved into the future across the United States (∼78,000 maternal lines). Our strategically designed collection circumvents some problems that can cloud the results of "resurrection" studies involving naturally preserved or existing seed collections that are available fortuitously. CONCLUSIONS: The resurrection approach can be coupled with long-established and newer techniques over the next five decades to elucidate genetic change and thereby vastly improve our understanding of temporal and spatial changes in phenotype and the evolutionary processes underlying it. [ABSTRACT FROM AUTHOR]

PREMISE OF THE STUDY: Climate change models for California predict a warmer, drier future, potentially resulting in shorter growing seasons. If phenotypic differences between closely related species currently distributed across a moisture and temperature gradient represent adaptations to their abiotic environment, then as conditions become warmer and drier, populations presently adapted to cooler and wetter conditions may evolve to become more similar to those adapted to warmer and drier conditions. Two sister species, Clarkia unguiculata and C exilis, are distributed across a moisture and temperature gradient in the southern Sierra Nevada, providing an opportunity to predict how this process may occur. METHODS: In a greenhouse experiment using wild-collected seeds from 11 populations in the southern Sierra Nevada, we examined relationships among elevation, climatic conditions, and population means for each trait, then evaluated bivariate relationships among maternal family means, using raw values and controlling for population and seed mass effects on phenotype. KEY RESULTS: Clarkia exilis occupied warmer, drier conditions, typically at lower elevations, than C. unguiculata did and flowered earlier and faster, producing smaller flowers with lower herkogamy. In C. unguiculata, petal area, herkogamy, and the rate of flower production were positively correlated with days tofirst flower. CONCLUSIONS: If selection favors earlier flowering, smaller petals, or faster flower production in C unguiculata, then the genetic correlations among these traits should reinforce their joint evolution. Moreover, the correlations between these traits and herkogamy may promote the evolution of self-fertilization as an indirect response to selection, a previously unrecognized potential outcome of climate change. [ABSTRACT FROM AUTHOR]

PREMISE OF THE STUDY: Understanding the evolutionary and ecological factors that determine plant distributions is of primary importance in botanical research. These factors may vary in predictable ways across different spatial scales, and thus, we can leverage scale to reveal the underlying processes limiting plant distributions. METHODS: We review various research considerations across local and geographic scales, including the investigation of dispersal and habitat limitation, evolutionary factors, abiotic and biotic factors, and research logistics. We also present two case studies, slender monkeyflower (Mimulus leptaleus) and cut-leaf monkeyflower (Mimulus laciniatus), in the California Sierra Nevada. KEY RESULTS: At a local spatial scale (within 50 m), no seeds were produced from plants sown at sites located just beyond known patches of M. leptaleus, but within the species' geographic range. At a much broader spatial scale (kilometers), at the highest and lowest elevations of the species' range, we found greatly reduced abundance and fecundity in plants sown outside of the geographic range limits of M. laciniatus. CONCLUSIONS: These cases illustrate two contrasting spatial scales, yet agree in their illustration of strong habitat limitation. We end by discussing future avenues of research and by suggesting ways botanical researchers can frame their studies to maximize information gained on species requirements, distribution limits, and conservation among varying spatial scales. [ABSTRACT FROM AUTHOR]

In an age of rapid global change, it is imperative that we continue to improve our understanding of factors that govern genetic differentiation in plants to inform biologically reasonable predictions for the future and enlighten conservation and restoration practices. In this special issue, we have assembled a set of original research and reviews that employ diverse approaches, both classic and contemporary, to illuminate patterns of phenotypic and genetic variation, probe the underlying evolutionary processes that have contributed to these patterns, build predictive models, and test evolutionary hypotheses. Our goal was to underscore the unique insights that can be obtained through the complementary and distinct studies of plant populations across species' geographic ranges. [ABSTRACT FROM AUTHOR]

Information about several papers discussed the inaugural meeting of the Pan-American Society for Evolutionary Development Biology on the goal to explore and define the future of evolutionary development of biology. Topics mentioned include gene regulatory networks' evolution, evolution of form and function, and patterning and plasticity in plants.

PREMISE OF THE STUDY: Clade-specific bursts in diversification are often associated with the evolution of key innovations. However, in groups with no obvious morphological innovations, observed upticks in diversification rates have also been attributed to the colonization of a new geographic environment. In this study, we explore the systematics, diversification dynamics, and historical biogeography of the plant clade Rhinantheae in the Orobanchaceae, with a special focus on the Andean clade of the genus Bartsia. METHODS: We sampled taxa from across Rhinantheae, including a representative sample of Andean Bartsia species. Using standard phylogenetic methods, we reconstructed evolutionary relationships, inferred divergence times among the clades of Rhinantheae, elucidated their biogeographic history, and investigated diversification dynamics. KEY RESULTS: We confirmed that the South American Bartsia species form a highly supported monophyletic group. The median crown age of Rhinantheae was determined to be ca. 30 Myr, and Europe played an important role in the biogeographic history of the lineages. South America was first reconstructed in the biogeographic analyses around 9 Myr ago, and with a median age of 2.59 Myr, this clade shows a significant uptick in diversification. CONCLUSIONS: Increased net diversification of the South American clade corresponds to biogeographic movement into the New World. This movement happened at a time when the Andes were reaching the necessary elevation to host an alpine environment. Although a specific route could not be identified with certainty, we provide plausible hypotheses to how the group colonized the New World. [ABSTRACT FROM AUTHOR]

PREMISE OF THE STUDY: Recent phylogenetic analyses based on molecular data suggested that the monocot family Zingiberaceae be separated into four subfamilies and four tribes. Robust morphological characters to support these clades are lacking. Seeds were analyzed in a phylogenetic context to test independently the circumscription of clades and to better understand evolution of seed characters within Zingiberaceae. METHODS: Seventy-five species from three of the four subfamilies were analyzed using synchrotron based x-ray tomographic microscopy (SRXTM) and scored for 39 morphoanatomical characters. KEY RESULTS: Zingiberaceae seeds are some of the most structurally complex seeds in angiosperms. No single seed character was found to distinguish each subfamily, but combinations of characters were found to differentiate between the subfamilies. Recognition of the tribes based on seeds was possible for Globbeae, but not for Alpinieae, Riedelieae, or Zingibereae, due to considerable variation. CONCLUSIONS: SRXTM is an excellent, nondestructive tool to capture morphoanatomical variation of seeds and allows for the study of taxa with limited material available. Alpinioideae, Siphonochiloideae, Tamijioideae, and Zingiberoideae are well supported based on both molecular and morphological data, including multiple seed characters. Globbeae are well supported as a distinctive tribe within the Zingiberoideae, but no other tribe could be differentiated using seeds due to considerable homoplasy when compared with currently accepted relationships based on molecular data. Novel seed characters suggest tribal affinities for two currently unplaced Zingiberaceae taxa: Siliquamomum may be related to Riedelieae and Monolophus to Zingibereae, but further work is needed before formal revision of the family. [ABSTRACT FROM AUTHOR]

PREMISE OF THE STUDY: Floral development can help to shed light on puzzling features across flowering plants. The enigmatic Amazonian monospecific genus Petaladenium of the legume family (Leguminosae) had rarely been collected and only recently became available for ontogenetic studies. The fimbriate-glandular wing petals of P. urceoliferum are unique among the more than 19000 legume species. Ontogenetic data illuminate the systematic position of the genus and foster our understanding on floral evolution during the early diversification of the papilionoid legumes. METHODS: Flower buds were collected in the field, fixed in 70% ethanol, and investigated using scanning electron microscopy (SEM). Results were compared with existing material from early-diverging papilionoid legumes. KEY RESULTS: Formation of sepals and petals shows bidirectional tendencies. Stamens arise in two whorls, and the single carpel arises concomitantly with the outer stamen whorl. Gland formation starts early on the edges of the wing petals. The carpel reopens for a short time when the initiation of ovules is visible. Stomata at the base of the hypanthium indicate that the flower functions like other standard flag blossoms. CONCLUSIONS: The floral ontogeny confirms the close affinity of P. urceoliferum with the florally heterogeneous, early-diverging papilionoid Amburaneae clade. The results strengthen the theory of a distinct experimental phase among early-branching papilionoid legumes during which a wider range of floral morphologies arose. Polysymmetry, monosymmetry, variable organ numbers, and a wide range of ontogenetic patterns laid the foundation for a successful canalization toward the more restricted but well-adapted dorsiventral papilionoid flag blossom. [ABSTRACT FROM AUTHOR]