About

Erika Edwards is a Professor in the Department of Ecology & Evolutionary Biology at Yale University. She serves as the Curator of Botany at the Peabody Museum of Natural History and is the Director of Marsh Botanical Gardens. Additionally, she holds the position of Acting Director of the Peabody Museum for the years 2025-2026. Her work involves the study of plant diversity and evolution, as well as plant structure and function. She is involved in teaching courses related to collections of the Peabody Museum, laboratory for plant diversity and evolution, and laboratory for plant structure and function. Her research and professional activities are centered around understanding plant biology and contributing to the academic and scientific community at Yale.

Research topics

• Biology
• Ecology
• Evolutionary biology
• Paleontology
• Agronomy
• Botany

Selected publications

• Corridors and Reservoirs: An Analysis of Inter‐Andean Historical Biogeography

  Journal of Biogeography · 2026-01-01

  articleSenior author

  ABSTRACT Aim The Andes are a global biodiversity hotspot, and the formation of this mountain range is linked to the rapid diversification of many lineages across the Tree of Life. The high species richness of the Andes might also act as a reservoir for lineages to disperse across the South American continent. Recent syntheses of Andean geological history and the accumulation of phylogenetic studies of different Andean clades present an opportunity for a synthesis of the historical biogeography of the Andean biota. Location The Andes. Taxon All taxonomic groups. Methods We conducted a meta‐analysis of phylogenetic studies, scoring disjunction events within and out of the Andes inferred from biogeographic reconstructions. Results We show that, across time and clades, dispersals among regions in the Andes are approximately as common as dispersals out of the Andes. The greatest number of extra‐Andean disjunctions originated from the northern Andes, even though the northern section of this mountain range is the most recently uplifted. There has been continued bi‐directional movement within the Andes over the last 50 million years. Dispersals northward occur at a slightly, but significantly, greater rate than dispersals southward. Andean plant crown clades tended to be older than animal crown clades, which almost exclusively originate in the last 30 million years. Main Conclusions Our findings reveal that the Andes have equally acted as a reservoir and a corridor of biodiversity across clades with widely divergent dispersal strategies.

  PublisherDOI

• Resolving the contrasting leaf hydraulic adaptation of <scp>C₃</scp> and <scp>C₄</scp> grasses

  New Phytologist · 2025-01-05 · 8 citations

  articleOpen access

  Summary Grasses are exceptionally productive, yet their hydraulic adaptation is paradoxical. Among C 3 grasses, a high photosynthetic rate ( A area ) may depend on higher vein density ( D v ) and hydraulic conductance ( K leaf ). However, the higher D v of C 4 grasses suggests a hydraulic surplus, given their reduced need for high K leaf resulting from lower stomatal conductance ( g s ). Combining hydraulic and photosynthetic physiological data for diverse common garden C 3 and C 4 species with data for 332 species from the published literature, and mechanistic modeling, we validated a framework for linkages of photosynthesis with hydraulic transport, anatomy, and adaptation to aridity. C 3 and C 4 grasses had similar K leaf in our common garden, but C 4 grasses had higher K leaf than C 3 species in our meta‐analysis. Variation in K leaf depended on outside‐xylem pathways. C 4 grasses have high K leaf : g s , which modeling shows is essential to achieve their photosynthetic advantage. Across C 3 grasses, higher A area was associated with higher K leaf , and adaptation to aridity, whereas for C 4 species, adaptation to aridity was associated with higher K leaf : g s . These associations are consistent with adaptation for stress avoidance. Hydraulic traits are a critical element of evolutionary and ecological success in C 3 and C 4 grasses and are crucial avenues for crop design and ecological forecasting.

  PublisherOA PDFDOI

• A high‐quality genome of the Atacama Desert plant <i>Cistanthe cachinalensis</i> and its photosynthetic behavior related to drought and life history

  New Phytologist · 2025-05-10 · 4 citations

  articleSenior authorCorresponding

  Crassulacean acid metabolism (CAM) photosynthesis has independently evolved many times in arid-adapted plant lineages. Cistanthe cachinalensis (Montiaceae), a desert annual, can upregulate CAM facultatively upon stress such as drought. Few studies, however, consider life history stages when measuring CAM activity or its facultative onset. To test the effect of drought and flowering on photosynthetic activity, we assayed Cistanthe individuals in fully watered and drought conditions, as well as fully watered individuals at pre-flowering and flowering life stages. We assembled and annotated a chromosome-scale genome of C. cachinalensis and compared it with the genome of Portulaca amilis and analyzed differential gene expression. Results show significantly upregulated CAM in drought conditions as compared to fully watered conditions; furthermore, flowering individuals showed slightly higher CAM activity as compared to pre-flowering plants, even when fully watered. Differential gene expression analyses provide preliminary support for the possible coregulation of CAM expression and reproduction. We emphasize the potentially missed significance of life history in the CAM literature and consider how the CAM biochemical module could become co-opted into other plant behaviors and responses, such as the shift to reproduction or flowering in annuals.

  PublisherDOI

• Phylogenomic analyses of the diverse desert-alpine plant lineage Cistantheae

  bioRxiv (Cold Spring Harbor Laboratory) · 2025-10-13

  preprintOpen accessSenior author

  Deserts and alpine habitats, though ecologically distinct, share similar environmental stressors such as drought and high radiation. Various plant lineages traverse both biomes, which is often associated with transitions in life history strategy, where annuality is more often associated with drier desert habitats and perenniality more common in higher elevations. One such lineage is Cistantheae (Montiaceae), a morphologically diverse herbaceous clade in western North and South America. We aimed to infer a robust phylogeny of the clade as a foundation for taxonomic and comparative work. We used double-digest RADSeq to generate reduced-representation genomic data from over 160 samples representing 48 putative species in Cistantheae. Maximum likelihood and coalescent-based phylogenetic methods were utilized to infer evolutionary relationships across the full clade and within major subclades. We tested for signatures of admixture and introgressive gene flow, and reconstructed ancestral life history and climate niche to identify patterns of correlated evolution. We inferred a well-resolved phylogeny of Cistantheae, providing strong support for relationships among subclades within Cistantheae. While many species relationships were clarified, we also found evidence of rampant gene flow and incomplete lineage sorting, particularly within the annual Cistanthe clade from the Atacama Desert. Life history is evolutionarily labile across the clade, and was strongly correlated with temperature/precipitation-related bioclimatic variables: annuals tend to occur in hotter, drier environments, while perennials in cooler, wetter. Elevational range was also evolutionarily labile, with several species occupying broad elevational gradients. We present the first densely-sampled, phylogenomic analysis of Cistantheae, providing key insights into species relationships in the clade. Repeated transitions in life history and climate niche, alongside wide elevational ranges, suggest that many Cistantheae species may be preadapted to both arid and montane habitats. This phylogeny will underpin further comparative, taxonomic, and phylogenomic studies in this ecologically important lineage.

  PublisherOA PDFDOI

• <scp>C₄</scp> photosynthesis and hydraulics in grasses

  New Phytologist · 2025-01-02 · 2 citations

  articleOpen access

  Summary The anatomical reorganization required for C 4 photosynthesis should also impact plant hydraulics. Most C 4 plants possess large bundle sheath cells and high vein density, which should also lead to higher leaf capacitance and hydraulic conductance ( K leaf ). Paradoxically, the C 4 pathway reduces water demand and increases water use efficiency, creating a potential mismatch between supply capacity and demand in C 4 plant water relations. Here, we use phylogenetic analyses, physiological measurements, and models to examine the reorganization of hydraulics in closely related C 4 and C 3 grasses. The evolution of C 4 disrupts the expected positive correlation between maximal assimilation rate ( A max ) and K leaf , decoupling a canonical relationship between hydraulics and photosynthesis generally observed in vascular plants. Evolutionarily young C 4 lineages have higher K leaf , capacitance, turgor loss point, and lower stomatal conductance than their C 3 relatives. By contrast, species from older C 4 lineages show decreased K leaf and capacitance. The decline of K leaf through the evolution of C 4 lineages was likely controlled by the reduction in outside‐xylem hydraulic conductance, for example the reorganization of leaf intercellular airspace. These results indicate that, over time, C 4 plants have evolved to optimize hydraulic investments while maintaining the anatomical requirements for the C 4 carbon‐concentrating mechanism.

  PublisherOA PDFDOI

• Improving the accuracy of automated labeling of specimen images datasets via a confidence-based process

  PLoS Computational Biology · 2025-11-12

  articleOpen accessCorresponding

  The digitization of natural history collections over the past three decades has unlocked a treasure trove of specimen imagery and metadata. There is great interest in making this data more useful by further labeling it with additional trait data, and modern "deep learning" machine learning techniques utilizing convolutional neural nets (CNNs) and similar networks show particular promise to reduce the amount of required manual labeling by human experts, making the process much faster and less expensive. However, in most cases, the accuracy of these approaches is too low for reliable utilization of the automatic labeling, typically in the range of 80-85% accuracy. In this paper, we present and validate an approach that can greatly improve this accuracy, essentially by examining the "confidence" that the network has in the generated label as well as utilizing a user-defined threshold to reject labels that fall below a chosen level. We demonstrate that a naive model that produced 86% initial accuracy can achieve improved performance - over 95% accuracy (rejecting about 40% of the labels) or over 99% accuracy (rejecting about 65%) by selecting higher confidence thresholds. This gives flexibility to adapt existing models to the statistical requirements of various types of research and has the potential to move these automatic labeling approaches from being unusably inaccurate to being an invaluable new tool. After validating the approach in a number of ways, we annotate the reproductive state of a large dataset of over 600,000 herbarium specimens. The analysis of the results points at under-investigated correlations as well as general alignment with known trends. By sharing this new dataset alongside this work, we want to allow biologists to gather insights for their own research questions, at their chosen point of accuracy/coverage trade-off.

  PublisherDOI

• Phylogenomic analyses of the diverse desert–alpine plant lineage Cistantheae

  Annals of Botany · 2025-12-16

  articleOpen accessSenior author

  BACKGROUND AND AIMS: Desert and alpine environments, although ecologically distinct, often share similar environmental stressors, such as drought and high radiation. Various plant lineages traverse both biomes, which is often associated with transitions in life-history strategy, whereby annuality is more often associated with drier desert habitats and perenniality is more common in higher elevations. One such lineage is Cistantheae (Montiaceae), a morphologically diverse herbaceous clade in western North and South America. We aimed to infer a robust phylogeny of the clade as a foundation for taxonomic and comparative work. METHODS: We used double-digest restriction site-associated DNA sequencing to generate reduced-representation genomic data from >160 samples representing 48 putative species in Cistantheae. Maximum likelihood and coalescent-based phylogenetic methods were used to infer evolutionary relationships across the full clade and within major subclades. We tested for signatures of admixture and introgressive gene flow, and we reconstructed ancestral life history and climatic niche to identify patterns of correlated evolution. KEY RESULTS: We inferred a well-resolved phylogeny of Cistantheae, providing strong support for relationships among subclades within Cistantheae. Although many species relationships were clarified, we also found evidence of rampant gene flow and incomplete lineage sorting, particularly within the annual Cistanthe clade from the Atacama Desert. Life history is evolutionarily labile across the clade and strongly correlated with temperature and precipitation-related bioclimatic variables: annuals tend to occur in hotter and drier environments, whereas perennials tend to occur in cooler and wetter habitats. Elevational range is also evolutionarily labile, with several species occupying broad elevational gradients. CONCLUSIONS: We present the first densely sampled phylogenomic analysis of Cistantheae, providing key insights into species relationships in the clade. Repeated transitions in life history and climatic niche, alongside wide elevational ranges, suggest that many Cistantheae species might be pre-adapted to both arid and montane habitats. This phylogeny will underpin further comparative, taxonomic and phylogenomic studies in this ecologically important lineage.

  PublisherOA PDFDOI

• University herbaria are uniquely important

  2024-05-02

  preprintOpen access1st authorCorresponding

  University herbaria play critical roles in biodiversity research and training and provide an interdisciplinary academic environment that fosters innovative uses of natural history collections. Universities have a responsibility to steward these important collections in perpetuity, in alignment with their academic missions and for the good of science and society.

  PublisherOA PDFDOI

• Caught in the Act: Incipient Speciation at the Southern Limit of <i>Viburnum</i> in the Central Andes

  Systematic Biology · 2024-06-04 · 5 citations

  articleSenior author

  A fundamental objective of evolutionary biology is to understand the origin of independently evolving species. Phylogenetic studies of species radiations rarely are able to document ongoing speciation; instead, modes of speciation, entailing geographic separation and/or ecological differentiation, are posited retrospectively. The Oreinotinus clade of Viburnum has radiated recently from north to south through the cloud forests of Mexico and Central America to the Central Andes. Our analyses support a hypothesis of incipient speciation in Oreinotinus at the southern edge of its geographic range, from central Peru to northern Argentina. Although several species and infraspecific taxa have been recognized in this area, multiple lines of evidence and analytical approaches (including analyses of phylogenetic relationships, genetic structure, leaf morphology, and climatic envelopes) favor the recognition of just a single species, V. seemenii. We show that what has previously been recognized as V. seemenii f. minor has recently occupied the drier Tucuman-Bolivian forest region from Samaipata in Bolivia to Salta in northern Argentina. Plants in these populations form a well-supported clade with a distinctive genetic signature and they have evolved smaller, narrower leaves. We interpret this as the beginning of a within-species divergence process that has elsewhere in the neotropics resulted repeatedly in Viburnum species with a particular set of leaf ecomorphs. Specifically, the southern populations are in the process of evolving the small, glabrous, and entire leaf ecomorph that has evolved in four other montane areas of endemism. As predicted based on our studies of leaf ecomorphs in Chiapas, Mexico, these southern populations experience generally drier conditions, with large diurnal temperature fluctuations. In a central portion of the range of V. seemenii, characterized by wetter climatic conditions, we also document what may be the initial differentiation of the leaf ecomorph with larger, pubescent, and toothy leaves. The emergence of these ecomorphs thus appears to be driven by adaptation to subtly different climatic conditions in separate geographic regions, as opposed to parapatric differentiation along elevational gradients as suggested by Viburnum species distributions in other parts of the neotropics.

  PublisherDOI

• Predicting photosynthetic pathway from anatomy using machine learning

  New Phytologist · 2024-01-04 · 9 citations

  articleOpen accessSenior author

  Plants with Crassulacean acid metabolism (CAM) have long been associated with a specialized anatomy, including succulence and thick photosynthetic tissues. Firm, quantitative boundaries between non-CAM and CAM plants have yet to be established - if they indeed exist. Using novel computer vision software to measure anatomy, we combined new measurements with published data across flowering plants. We then used machine learning and phylogenetic comparative methods to investigate relationships between CAM and anatomy. We found significant differences in photosynthetic tissue anatomy between plants with differing CAM phenotypes. Machine learning-based classification was over 95% accurate in differentiating CAM from non-CAM anatomy, and had over 70% recall of distinct CAM phenotypes. Phylogenetic least squares regression and threshold analyses revealed that CAM evolution was significantly correlated with increased mesophyll cell size, thicker leaves, and decreased intercellular airspace. Our findings suggest that machine learning may be used to aid the discovery of new CAM species and that the evolutionary trajectory from non-CAM to strong, obligate CAM requires continual anatomical specialization.

  PublisherOA PDFDOI

Recent grants

• DISSERTATION RESEARCH: Phylogeny and evolutionary exploration of the C3-CAM phenotypic space in Calandrinia (Montiaceae)

  NSF · $21k · 2016–2017

• CAREER: Defining the evolutionary trajectory of CAM photosynthesis in Portulacineae (Caryophyllales)

  NSF · $800k · 2013–2017

• Phylogeny and the evolution of succulence in the Portulacineae (Caryophyllales)

  NSF · $535k · 2010–2014

• CAREER: Defining the evolutionary trajectory of CAM photosynthesis in Portulacineae (Caryophyllales)

  NSF · $118k · 2017–2020

• Collaborative Research: Replicated evolution of leaf form in a neo-tropical radiation of Viburnum (Adoxaceae)

  NSF · $348k · 2017–2021

Frequent coauthors

• Felipe Zapata

  758 shared

• Austin Mast

  756 shared

• Erick Matsen

  Yale University

  754 shared

• Edward Susko

  Dalhousie University

  754 shared

• Brian M. Wiegmann

  North Carolina State University

  754 shared

• Dan Faith

  University of Connecticut

  754 shared

• Thomas J. Near

  Yale Peabody Museum

  754 shared

• Sebastian Höhna

  Ludwig-Maximilians-Universität München

  754 shared