Living Collections Research

Research In the Collections

In addition to staff scientists, the Arnold Arboretum and its rich resources are utilized by an extensive network of researchers. With more than 15,000 well-documented, living plant specimens representing almost 4,000 taxa, the living collection is ideal for comparative studies of morphology, phylogenetics, physiology, development, ecology, and biodiversity, among other disciplines. In addition to plants, scientists may study other inhabitants of the Arnold Arboretum’s ecosystem including insect, amphibian, and bird communities. Selected projects organized below by project start date highlight the diversity of research projects utilizing the landscape and living collections. Learn more about the Arboretum’s collections policy or request access to the Arboretum for research purposes.

Hemlock on the Edge The Preisser Lab at The University of Rhode Island is interested in (1) the resistance mechanisms of hemlocks (Tsuga spp.) against insect herbivores and (2) the differences in mechanisms between species. They will use the diverse collection of hemlocks at the arboretum and hormone treatments to better understand the chemical and physiological differences in how species from around the world defend themselves and which defensive hormone pathways control certain defenses.
scholar tree As part of a multi-institutional NSF funded project (PI: Pamela Soltis), Gregory Stull, graduate student in the Soltis Lab at the University of Florida, is collecting samples from more than one hundred Arboretum wild-collected accessions. The goal is to examine the ecological assembly and evolution of northern temperate forests that are disjunct between Eastern Asia and Eastern North America using phylogenomics, biogeography, and observations of microbial interactions to better understand temperate biodiversity.
Kasia Zieminska Putnam Fellow Kasia Zieminska aims to understand how tree anatomy impacts function. By focusing on diverse species in the Arboretum’s living collections, she will examine the relationship between diversity in anatomical structure and water storage mechanisms and how this relationship influences plant biodiversity and ecological strategies.
Kuo-Fang Chung Kuo-Fang Chung, a Sargent Award recipient and associate research fellow at the Biodiversity Research Center, Academia Sinica in Taiwan will be exploring the rich herbarium and living collections of Berberis to clarify the taxonomy of the genus.
Callin Switzer Kalmia has a unique method of pollen release in which the pollen is catapulted out of the anthers when a pollinator lands on the flowers. Callin Switzer, a Sinnott Award recipient and graduate student in the Hopkins Lab, will examine this unique pollination method using high-speed videography.
Dan Sullivan Dan Sullivan, a Sargent Award recipient and visiting fellow of the Arnold Arboretum, is developing techniques for rapid and inexpensive DNA extraction as well as cultivating collections of extracted DNA libraries and silica-dried leaves for future phylogenetic research.
Danilo Fernando Danilo Fernando is a Jewett Prize recipient and Associate Professor at the State University of New York. His research at the Arboretum will focus on the reproductive biology of Actinidia arguta (hardy kiwi), a dioecious species whose flowers are functionally unisexual.
Alex Susko A PhD candidate from the University of Minnesota and Deland Award recipient, the research of Alexander Susko focuses on abiotic stress tolerance in Rhododendron. At the Arboretum, Alexander will collect and sequence deciduous azaleas originally collected across the geographic and environmental range to identify genetic targets of selection associated with differing environmental responses.
Jon Mahoney As part of the Aronia breeding program, Jonathan Mahoney, a Master’s student at the University of Connecticut and Deland Award recipient, is investigating the mating systems and compatibility issues of intergeneric hybridization between Aronia and related taxa.
Meng Li Meng Li, a Ph.D student in the Chengdu Institute of Biology at the Chinese Academy of Sciences, is interested in the role of hybridization on species diversification. As part of his Hu Award, Li will spend one year at the Arboretum to examine hybridization in Sorbus.
Meri Bond - Magnolia A post-doctoral fellow at Yale University and a Jewett Prize recipient, the research of Adam Roddy focuses on the physiological aspects of the evolution of flowering plants. Examining 25 species of basal angiosperms in the Arboretum’s living collections, Adam will measure physiological traits associated with water balance to examine the trade-offs between water transport, water storage, and the ability to maintain turgid and showy flowers.
Kim Shearer Lattier Genome size and ploidy data of angiosperms are necessary for developing objectives of genome sequencing and breeding projects.  While maples (Acer L.) are ubiquitous in the landscape, there is relatively little genome size and ploidy information available for the genus.  For her M.S. thesis at Oregon State University, Kim Shearer Lattier collaborated with arboreta and botanical gardens in the United States to analyze the North American maples in the collections using flow cytometry and traditional cytology.
Ben Bell Benjamin Bell is a PhD student at the University of Manchester investigating the geochemistry of Cedrus atlantica pollen and what it can tell us about the environment, with a focus on stable isotope and FTIR analysis. Pollen samples from the arboretum will be used to understand the environmental response outside the native range in Morocco.
Norbert Holstein Maximilian Weigend, Professor and Director of the Bonn University Botanic Garden, and Norbert Holstein (pictured), postdoctoral researcher at the University of Bonn, are developing molecular barcodes to aid in identifying members of selected genera of Betulaceae and Fagaceae. These taxa can be very difficult to identify based on morphology alone.
Chase Mason Chase Mason, Arnold Arboretum Putnam Fellow, is studying the evolution of leaf physical and chemical defenses in relation to the leaf economics spectrum (LES), habit, and species’ source climate across 16 woody genera. LES relates the initial investment of carbon during leaf development with the net carbon gain of that leaf. Plants employ various LES strategies which impacts their adaptability to environmental conditions and stresses.
Juan Losada As a Research Associate of Leslie Lab at Brown University, Juan Losada is using the conifer collection to explore how anatomical divergences during development can generate morphological disparity in seed cones of the family Pinaceae.
Althea Northcross Formerly studying Landscape Architecture at Harvard’s School of Design, Althea Northcross independently continues her research on the history and future canopy of the Peter’s Hill Natural Woodland. Her work involves archival research about the history of the plot, GIS mapping of the current canopy, a tracing of the emerging canopy gaps in the aging oak canopy, and includes projections about the probable future canopy composition of the woodland.
Steve Decina A Deland Award recipient and PhD candidate working with Drs. Lucy Hutyra and Pamela Templer at Boston University, Steve Decina aims to understand how urbanization affects biogeochemical cycles. By comparing collection sites in urban areas, including the Arboretum, he will quantify nitrogen deposition in multiple urban sites.
Carly Troncale Carly Troncale is a MLA Candidate at the Harvard Graduate School of Design. As part of an independent study project, she is working to expand a botanical survey of the Bussey Brook Meadow followed by the creation of a tree map of the spontaneous vegetation in the area.
Jianhua Li Jianhua Li is an associate professor of biology at Hope College and former Arnold Arboretum senior scientist. Returning to the Arboretum for his sabbatical as a Sargent Award recipient, Jianhua will focus on the reconstruction of the early tree of life of Acer. The evolutionary relationships of this important and diverse tree genus has, thus far, remained largely unresolved hindering our understanding of the natural history of maples.
Morgan Moeglein Morgan Moeglein is graduate student in the Edwards Lab at Brown University. She is studying the environmental and genetic factors governing leaf shape in the genus Viburnum utilizing the living collection of the Arnold Arboretum.
Marston 3 An archaeologist specializing in reconstructing environmental change in the ancient Mediterranean world, John Marston (Boston University) identifies carbonized wood fragments from archaeological sites to study forest succession, arboriculture, and deforestation. He uses wood specimens from the Arboretum as a comparative collection to help identify archaeological wood charcoal from the Mediterranean, Middle East, Europe, China, and North America.
Bryan Denig Bryan Denig is a researcher at Cornell University’s Urban Horticulture Institute. Utilizing the Arboretum’s Quercus collection, he conducts research developing a protocol for the asexual propagation of oaks via tissue culture. A reliable micropropagation method suitable for a diverse range of oak species has many potential applications, such as cloning individuals of horticultural value, preserving the genetics of historic trees, and aiding in the conservation of endangered Quercus species.
Calum Bowden Portrait 004 Before 1941, the Dawn Redwood – Metasequoia glyptostroboides – did not exist. And until 1946, the new genus existed only in fossil records. Calum Bowden investigates the stories people have used to create this living thing over time. Through a projection installation which now lives online at, the fossil records, historical archives, photographs, accessions data, and journal articles are brought forward in a new way.
P1090981-1 A single linage of Arabidopsis thaliana was introduced to North America 200 years ago and has since experienced diversification. Using A. thaliana populations found naturally in the Arboretum, Gautam Shirsekar, Jane Devos, and Detlef Weigel (Weigel Lab) will examine adaptation of the population to the common white rust disease pathogen Albugo candida.
Ailene Ettinger Ailene Ettinger, Arnold Arboretum Putnam Fellow, focuses on predicting the response and sensitivity of plants to a changing climate. By examining diverse trees growing in a common environment, she can identify functional traits that are important for success outside their historical conditions.
Jessica Savage Jessica Savage is interested in understanding how seasonal changes in vascular activity influence flowering and carbon allocation. As an Arnold Arboretum Putnam Fellow, Jessica is comparing xylem and phloem anatomy, physiology and function in precocious flowering species (those that flower before the leaves emerge) with related species that flower later in the season.
Andrew_03-05-14sq A geneticist at the USDA Forest Service and a Sargent Award recipient, Andrew Groover will perform RNA sequencing (RNA-seq) on cambium and wood forming tissues of diverse trees in the Arboretum. Potentially important regulatory genes expressed in these tissues will be identified and analyzed as a first step to understanding the evolution of woody growth.
Ling Guo is a curator at the Beijing Botanic Garden and a Jewett Prize recipient. Utilizing the Arboretum’s Malus collection, she will conduct research to improve the databases and knowledge of ornamental crabapples as a Registration Authority. Her database will focus on the flowers of Malus to improve the understanding of flowering time.
ZhangYJ-3 In some species of Acer, stem pressure generation during thawing results in sap production which is used to make maple syrup. This is in contrast to most trees which exude sap during freezing. Working in the Acer collection, Yong-Jiang Zhang, Hu Exchange Award recipient and post-doctoral fellow in the Holbrook Lab, aims to understand the physiological mechanisms of stem pressure generation and the role of xylem structure in this mechanism.
ProjectPineCone Renee Galeano-Popp, a retired USDA Forest Service botanist, started Project Pine Cone as a way to share the beauty and diversity of botany. With additional specimens collected at the Arboretum by volunteers, she now has 76 of the 115 pine species represented in a permanent display at Colorado State University and in travel-ready form for schools, groups and organizations to educate and inspire. Volunteer David Surette is shown in the photo.
Salcedo Mary Salcedo is a graduate student in the Combes Lab at the Concord Field Station.  She is studying neuromuscular control during flight in dragonflies.  Major behaviors of dragonflies, such as predation, competition and mating, are all performed while in flight. Using catch and release techniques and high-speed videography, she will compare the neuromuscular effects of these behaviors on dragonfiles from a variety of different locations.
McCarragher_ArnoldArboretum2 Shannon McCarragher is a Ph.D. Candidate in the Geography Department at Northern Illinois University. She is studying the evolution and ecology of the invasive Amur honeysuckle (Lonicera maackii) and its relationship to the success of native white oak (Quercus alba) populations in Illinois. Using both historical and living specimens of Amur honeysuckle from the Arboretum, she will explore the genetic variation between and among geographically distant populations.
Callin_Switzer_Buzz_Pollination_Combes_Lab_02 Callin Switzer is a graduate student in the Combes Lab at the Concord Field Station.  He is studying pollination by bumblebees.  He records bumblebees’ sounds as they fly and vibrate their bodies, shaking pollen from flowers’ anthers.  Analyzing these recordings gives insight into pollinator behaviors on a variety of plants throughout the foraging season.
JessicaSavage Jessica Savage, a Postdoctoral Fellow at Harvard University, is examining the relationship between cell structure in the xylem and phloem, the two main parts of the vascular system in collaboration with N. Michele Holbrook from Harvard and Michael Knoblauch from Washington State University. The main goal of this research is to determine whether phloem and xylem cells exhibit correlated evolution across the flowering plant phylogeny.
C_japonicumARNOLD Commonly called Katsura, there are only two species of Cercidiphyllum (C. japonicum and C. magnificum), both of which are well represented at the Arboretum. Craig Carlson, a graduate student in the West Lab at North Dakota State University, is developing micropropagation techniques for this important ornamental tree.
Stacey Young sq Stacey Leicht Young, Arboretum Putnam Fellow, is examining the ecological and reproductive strategies required for lianas (woody vines) to be successful in its environment. Utilizing the Arboretum’s Leventritt Shrub and Vine collection, Stacy will compare and contrast the functional traits of North American species with East Asian species growing in a common environment.
KristelPicture Kristel Schoonderwoerd is a visiting fellow in the Friedman Lab from the Erasmus Mundus Master Program in Evolutionary Biology. At the Arboretum, she is studying reproductive traits in angiosperms on a macroevolutionary scale and learning techniques to examine the embryo sac development of Franklinia alatamaha.
RosanneHealyTrufflingFSP2009 Rosanne Healy, Sargent Award recipient and post-doctoral fellow at the University of Minnesota, is focusing on ectomycorrhizal fungi that are present on roots of trees in well-spaced habitats like the Arboretum. She plans to sequence, identify and compare the fungal partners on the roots of Oak trees present at the Arboretum with those at the Harvest Forest.
Fagus grandifolia 23274A Hao setup The tree trunk plays an important role in whole-plant water relations but remains the least studied aspect in the plant water transport pathway. Guangyou Hao, Arnold Arboretum Putnam Fellow, and colleagues are measuring the water potential gradient across the trunk directly in the tree to estimate the relative contribution of water storage to daily water use and compare xylem vulnerability to cavitation in a different part of the hydraulic pathway.
Kevin Block Kathryn Weglarz is a Deland Award recipient and graduate student in the von Dohlen Lab at Utah State University. Where much focus has been placed on understanding plant-insect interactions, her goal is to examine the less thought of interaction between the host plant and the bacterial symbionts present in the saliva of the insects.
Stan Hokanson MAES_20090528__FEL8045_4_4sq Stan Hokanson and Steve McNamara from the University of Minnesota and the Horticulture Research Center at the Minnesota Landscape Arboretum are adding multiple taxa of Forsythia from the Arboretum’s collection to their field trials and laboratory experiments. Characters such as cold hardiness and floral traits will be evaluated for selection and incorporation into their breeding programs.
Nanjing Botanical Garden Nanjing Botanical Garden Mem.Sun Yat-Sen of China is interested in beach plum (Prunus maritima), a kind of Halophyte. Using the Arbretum’s living collection, the garden plans to carry out the study on genetic diversity of beach plum, and to display the unusual plant to tourists at their garden and seashore of Jiangsu province of China
IMG_4402 Peter Del Tredici, Ned Friedman, and Noah Fierer from the University of Colorado sequenced the microbial life residing on different regions (leaves, bark, north, south, etc.) of Ginkgo biloba. This is the first-ever tree microbiome representing the entire community of microbes. more»
Cryptomeria_japonica A PhD candidate at the University of Melbourne in Australia, Stephanie Conway is interested in the role of the shoot apical meristem in the evolution of shoot architecture. As a visiting fellow in the Friedman Lab, she will focus on shoot apical meristems utilizing the extensive collection of gymnosperms at the Arboretum.
Berberis gilgiana A Jewett Prize recipient and post-doctoral fellow in the Kramer Lab in the Department of Organismic and Evolutionary Biology at Harvard University, Bharti Sharma is interested in the evolution of petal identity and development. Capitalizing on the tremendous floral diversity found in the barbarry family (Berberidaceae), she will compare petal development using microscopy and comparative gene expression techniques in Epimedium rubum and Berberis gilgiana.
LIDAR Forest2  The Arboretum provided a unique testing ground for the autonomous navigation of mobile robots through unpredictable terrain. Karl Iagnemma and colleagues from the Robotic Mobility Group at MIT have developed methods to model the ground plane and tree stems using a remote sensing technology called LiDAR (Light Detection and Ranging). Read more in a paper published in the Journal of Field Robotics.
Prunus incisa Erica Fadon is a PhD student in the Herrero Lab at the Pomology Department of the Aula Dei Experimental Station–CSIC, Spain. Using the Arboretum’s living collection, Erica closely examined the development of sweet cherry flowers (Prunus avium) in order to determine which stage the flowers undergo winter dormancy.
A Master’s student at the Harvard Extension School, Kevin Block is evaluating the susceptibility of a new hemlock species, the Ulleung hemlock, to hemlock woolly adelgid, Adelges tsugae. The Arnold Arboretum is one of the only living collections holding the Ulleung hemlock, allowing comparative studies on resistance. With the adelgid devastating our native Eastern hemlock, Tsuga candensis, understanding differences in resistance is beneficial to hemlock forest ecology.
Leena Lindén of the University of Hellsinki, Finland, and colleagues are developing methods for micropropagation, DNA-fingerprinting, and cryopreservation of common lilac genotypes to aid in the characterization and conservation of genetic resources. A second project utilizes the Arboretum’s Malus collection to develop microsatellite markers.
As part of his master’s thesis at the University of Delaware, Matthew Lobdell is conducting a review of the genus Styrax in the Arboretum’s historical records and herbarium. He will verify taxonomic descriptions as well as compile information on horticultural traits, hardiness, propagation, and historical use with the goal of creating a reference guide.
Malus_'Purple Prince' 315-95-C Jorge Lora is a Jewett Prize recipient and post-doctoral fellow with Professors Iñaki Hormaza and Maria Herrero at Experimental Research Stations of the Spanish Council for Scientific Research (CSIC), Spain. Using plants in the Arboretum’s Rosaceae collection, he will compare ovule morphology from the earliest stages to maturity as well as the expression pattern of a gene thought to be important in ovule development.
research-page Cary Pirone, Arnold Arboretum Putnam Fellow, investigates how chemical signals mediate biological phenomena. Current research involves exploring the complexities of pollination drops (ovular secretions) of several conifer species and ginkgo using biochemical and anatomical approaches.
Bee on Buttonbush Bees are important indicators of the health of an ecosystem. Georgia Shelton, a Harvard undergraduate (Class of 2014), and Brian Farrell, Professor of Biology at Harvard University, are documenting bees at the Arboretum. The diversity of bee species found in this urban ecosystem will be compared to a five-year study in the Boston Harbor Islands National Park. Follow this Bee-search on Georgia’s blog.
Tim Dickinson and other botanists at the Royal Ontario Museum in Toronto, Canada, are studying Crataegus evolution, and have sampled hawthorns at the Arboretum to include Eurasian taxa, like Crataegus maximowiczii and C. germanica. DNA sequencing has begun to demonstrate how important hybridization has been in Crataegus, something that Arboretum Founding Director Charles Sprague Sargent, a pioneer in the study of the genus, would not have expected.
Linn Jennings in Bussey Brook Meadow Harvard Forest ecologists Kristina Stinson, David Foster, and Sydne Record are collaborating with Chris Rogers (UMass School of Public Health) to investigate the effect of climate on ragweed and human health. Studying ragweed populations from Boston to the Berkshires (including Bussey Brook Meadow at the Arboretum), the team seeks to determine how geographic variation in plant growth, abundance, and peak flowering time relate to pollen output and allergic potency.
Emily Scherbatskoy Emily Scherbatskoy, a Deland Award recipient, worked in the Friedman Lab with Julien Bachelier. Her research is focusing on the comparative morphology of female gametophytes in diverse conifers present in the Arboretum’s gymnosperm collection.
10mm Eurycea bislineata Zack Lewis from the Hanken Laboratory at Harvard, is investigating lung development in salamanders. He uses the Arboretum’s natural salamander populations for studies on the development and evolution of lung loss in the family Plethodontidae (lungless salamanders).
hops_trichome Noeline Morrissey, a master’s student in the Friedman Lab, is focusing on trichome morphology and development by comparing the multiple forms of trichomes in hops (Humulus lupulus) and related genera present in the Arboretum’s living collection.
Ashley Clingen As part of a large collaboration, Ashley Clingen and Jean-Noel Candau are investigating whether Megastigmus, a genus of chalcid wasp, is actively parasitizing the seeds of Cupressaceae species in North America. This project is designed to keep researchers one step ahead of a possible North American invasion of this insect, to gather information on the phenology of Megastigmus parasitism, and, ultimately, to prevent its further infestation worldwide.
Guangyou Hao Guangyou Hao is an Arnold Arboretum Putnam Fellow. He is interested in plant ecophysiology with a focus on comparative study in plant xylem water transport and its adaptive significance in coping with environmental stresses, such as drought and freezing temperature. He is currently working on hydraulics of conifers using the Arnold Arboretum collections.
Quercus glandulifera David Valbracht is working towards a certificate in botanical art and illustration. Using the wide range of oak species found in the Arboretum, he is preparing an illustrated guide to oaks. In addition, his watercolor paintings inspired by the oaks will be exhibited at the Wellesley College Greenhouses.
Juan Losada Juan Losada is a Deland Award recipient and PhD candidate with Professor Maria Herrero in the Pomology Department of the Aula Dei Experimental Station–CSIC, Spain. His graduate work has focused on the reproductive biology of apples (Malus spp.). Juan spent the summer working at the Weld Hill Research Building to expand his studies to include species in the Arboretum’s Magnolia collections.
Rhododendron Fargesii Richard Primack of Boston University is surveying the living collection to determine the variation among species in spring leaf out times. The earliest species leaf out in late March and early April and the last species only leaf out in late May and early June. What are the ecological and evolutionary explanations for such large differences among species? Read more in Arnoldia.
Prunus nipponica Jun Wen, research scientist and curator at the Smithsonian Institution, is working on the evolution of intercontinental biogeographic disjunctions in the Northern Hemisphere including several species of Prunus at the Arboretum. As a Mercer and Putnam fellow in 1991-1992, she did a series of molecular and morphological studies on eastern Asian/eastern North American disjuncts.
2010 and earlier
Hugh McAllister of the Ness Botantic Gardens at the University of Liverpool and Sargent Award recipient, studied Sorbus and Betula trees in the Arboretum in connection with the preparation of Curtis’s Botanical Magazine (Kew, UK) monographs on these genera. An unexpected discovery was a new hybrid of two distantly related birches, Betula maximowicziana x B. ermanii.
hemlock woolly adelgid Pamela Templer is an assistant professor in the Department of Biology at Boston University. As a forest ecologist, she studies the role of plant-microbial interactions in nutrient retention and loss. Her research at the Arnold Arboretum examines the impact of the hemlock woolly adelgid and atmospheric nitrogen deposition on nutrient cycling. She has also used herbarium specimens to examine how past changes in atmospheric chemistry have impacted the physiology of trees.
Garth Holman Garth Holman of the University of Maine is studying the evolutionary history of the Pine family (Pinaceae), and species-level relationships in true firs (Abies) and hemlocks (Tsuga). The Arnold Arboretum holds more than 100 species of plants in the Pinaceae, enabling Holman to collect fresh tissues and conduct morphological studies through many characters unavailable from standard museum specimens including phenology, growth habitat, and mature bark.
Woody plant respond to CO2 levels Woody plants can respond to rising carbon dioxide levels and higher temperatures by modifying their leaves. Using living plants and herbarium specimens, Boston University researchers Abraham Miller-Rushing, Pamela Templer, Richard Primack, and their students found that oaks, maples, and hornbeams maintain their water use efficiency by adjusting the size and density of their stomata, the pores on the bottom surface of the leaves.
Lorna Gibson in the bamboos Bamboo has many advantages as a construction material: it is a renewable, sustainable resource and has mechanical properties similar to wood, but grows much faster. Lorna Gibson and her research group from MIT are studying the microstructure and mechanical properties of bamboo and developing micromechanical models for its behavior.
Lucy Hutyra Lucy Hutyra is an assistant professor of in the Department of Geography and Environment at Boston University. Her research focuses on terrestrial ecosystems and atmosphere-biosphere exchange of carbon dioxide. Lucy is a leader of the Boston ULTRA-Ex studying Boston’s carbon metabolism across urban-to-rural gradients.
Photo of pit traps taken by Tracey MCNeill of UEI Boston Metropolitan Area ULTRA-Ex is a NSF-funded project that aims to increase our understanding of how urban “greening” efforts contribute to community ecology and social health. As part of this study, project leader Paige Warren, Michael Strohbach and Rachel Danford of UMass-Amherst are examining bird and arthropod communities in the Arboretum.
Rubus idaeus Jer-Ming Hu is an associate professor at the Institute of Ecology and Evolutionary Biology, National Taiwan University. He is interested in the phylogenetics and evolutionary developmental biology of the perianth. He is also working on the systematics of Rubus (Rosaceae) and uses the Arboretum’s living collections for phylogenetic and floral morphological studies.
Joao Loureiro In deciduous azaleas, there are 2 genetically distinct clades which separate according to ploidy level. Sally and John Perkins in collaboration with a research team from the University of Coimbra, Portugal, are comparing controlled crosses of tetraploid and diploid clades of deciduous azaleas. The diploid clade accepts pollen from the tetraploid clade and results in well-developed seedpods, but the tetraploid clade rejects the reciprocal cross.
Kathryn Richardson and Rose Abramoff The impact of climate change on plants has been the focus of research by Richard Primack, students from Boston University, and Peter Del Tredici. Herbarium specimens collected from the living collection in the past and dated photographs can be used to show that plants are now flowering 10 days earlier than they did 100 years ago, and that plants flower earlier in warm years. Read more in Arnoldia.