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Graduate Student and Postdoctoral Research
         
  Kjell Bolmgren Kjell Bolmgren  —  Plant phenology has rarely been explored in a phylogenetic context, probably because it has been considered difficult and laborious to compile the necessary data. In the project “Phylogenetic and Geographic Comparative Studies in Plant Phenology” we will make use of herbarium collections and develop methods that will allow large-scale comparisons of flowering time. We will approach the ecology and evolution of flowering time in relation biogeography, climate, dispersal mode, and phylogeny.    
 
 
  Vicente Garcia Vicente Garcia  —  My research interests encompass vascular plant systematics, floristics, and conservation with an emphasis on systematic and phylogenetic studies. I am particularly interested in the historical biogeography, reproductive biology, taxonomy, evolutionary ecology, and ethnobotany of the genus Piper (Piperaceae). The pepper genus consists of well over 1,000 species in a pantropical distribution. It includes several commercially grown and ethnobotanically important species such as black pepper (Piper nigrum), betel leaf (Piper betle), and kava (Piper methysticum).    
 
 
  Danica Taylor Harbaugh Danica Taylor Harbaugh  —  My doctoral dissertation research focuses on the hemiparasitic plant genus Santalum (Santalaceae), which includes the economically and ethnobotanically important sandalwoods, commonly used in incense and perfume. A phylogeny of the entire genus, which includes nearly 30 named taxa, has been reconstructed using a combination of nuclear ribosomal (ITS, ETS), low-copy nuclear (3′waxy) and chloroplast (3′trnK) gene regions. The phylogeny has elucidated novel biogeographic patterns across the Pacific Basin, including two independent colonization events to Hawaii, and at least one dispersal out of Hawaii. The phylogeny will be used to examine patterns in ethnobotanical uses, as well as to revise the taxonomy of the genus.    
 
 
  Eric SJ Harris Eric SJ Harris  —  I am interested in human uses of bryophytes, a field of study sometimes called “ethnobryology”. I have been researching two medicinally important mosses: Plagiomnium and Rhodobryum. Plagiomnium has been used to treat skin infections and swelling by the Bella Coola and Oweekeno First Nations of western Canada. I have been studying the phylogeny and phytochemistry of Plagiomnium to understand the evolution of putatively bioactive chemicals in this genus. Rhodobryum is used in Southwest China to treat minor heart problems. I have been conducting ethnobotanical research to understand the variation in use and knowledge of Rhodobryum in the areas of Southwest China where this moss is used. I hope to use my research to shed light on the biological processes that make mosses amenable to human use, and the cultural processes that incorporate mosses into human life.    
 
 
  Ruth Kirkpatrick Ruth Kirkpatrick  —  I study the fern genus Pellaea and other cheilanthoid relatives. Cheilanthoid ferns have a worldwide distribution and thrive in exposed rocky habitats where there are extended dry periods during part of the year. They have evolved structural and chemical adaptations that enable them to tolerate drought and desiccation, making them an ideal group to study for understanding genetic, morphological and physiological changes associated with drought and desiccation tolerance. I use molecular, morphological, cytogenetic, and eco-physiological characters to generate phylogenetic hypotheses and investigate the evolutionary relationships, character evolution, biogeography, and adaptive features of these plants. I have also performed a desiccation-tolerance (D-T) experiments. Results showed that levels of D-T among these ferns are negatively correlated with mean annual rainfall in their native habitats. D-T data analysis suggests an adaptive trade-off between levels of D-T and maximum baseline levels of photosynthesis. The biogeographic history of Pellaea in California appears to have involved loss of D-T as they migrated north and up in elevation where they found cooler temperatures and more moisture. Understanding how plants have responded to changes in their environments in the past will allow us to be better prepared to make more accurate predictions about their response to current and future environmental change.    
 
 
  Bianca Knoll Bianca Knoll  —  Several ferns in the family Pteridaceae are the only plants known to hyperaccumulate arsenic. My dissertation goal is to discern the phylogenetic relationships of these taxa in order to place the arsenic hyperaccumulation trait into an evolutionary perspective. Hopefully, this will allow me to make suggestions for non-weedy species that can be used in arsenic phytoremediation. I focus on the fern genera Pityrogramma and Pteris, and I conduct my fieldwork in Central and South America.    
 
 
  Anna Larsen Anna Larsen  —  I am studying the historical co-movement of plants and people in Oceania from a phylogenetic perspective. Within the last 5,000 years, the Lapita people migrated from Southeast Asia or Near Oceania as far east as Fiji and Tonga. Following at least 1,000 years of cultural isolation, an ancestral Polynesian culture emerged in the Samoan and Tongan archipelagoes and evolved as humans spread through the islands of the Polynesian triangle over the next two thousand years. Consequently, variation in Polynesian cultural traditions, artifacts, and indicator plants reflects the chronology of island settlement. I am using two sources of data to reconstruct the human migration route: genetic variation in the Candlenut tree (Aleurites moluccana (L.) Willd.) and variation in the production, decoration and use of Polynesian barkcloth (tapa).    
 
 
  Abby Moore Abby Moore  —  I am studying the genus Grindelia in the tribe Astereae of the Asteraceae. It has yellow ray and disc flowers and resinous involucres that give it the common name of gumweed. Grindelia is native to open habitats throughout western North America, Mexico, and southwestern South America. Members of the genus grow in a wide variety of habitats and many different soil types including salt marshes, coastal dunes, serpentine soils, dry roadsides, and open pine woodlands. In addition to this diversity of habitats, Grindelia shows a wide range of morphologies from sub-shrubs and upright, much-branched perennials to plants with unbranched stems growing from a basal rosette and prostrate forms. However, all of these forms are connected by intermediates and it is not clear how much gene exchange there is and how much of the variation is phenotypic. I am currently examining the phylogeny of the genus using gene sequence data. In the future I hope to examine the morphological variation in western North American species more closely using common garden experiments and investigate gene flow among the populations growing in different habitats using population genetics approaches.    
 
 
  Marattiaceae Andrew Murdock  —  My dissertation research focuses on the evolution of the tropical fern family Marattiaceae, a “living fossil” lineage whose morphology has seemingly changed very little for millions of years. For this research I have collected ferns throughout the Pacific and Asia and has studied the morphological and DNA sequence evolution across the diversity of the Marattiaceae. Additionally, I am studying genomic and morphological evolution of green plants, working on floristics projects in the Carquinez Strait region of California and on the island of Moorea, French Polynesia, and actively pursuing research on ferns in California, Oregon, and Washington.    
 
 
  Eryngium Michael Park  —  I am interested in the evolution of leaf heteroblasty (seasonal heterophylly) in Eryngium (Apiaceae) of the New World and its consequences for adaptation to vernal pool habitats or other seasonally water inundated environments. I am working with Bruce Baldwin on the pollination syndrome in Collinsia, specifically the link between flower size and self-fertilization. I am also taking a fresh look at the systematics of Collinsia as well as collaborating with Robert Preston on the Eryngium treatment for the second edition of The Jepson Manual. I am working on the conservation of the annual Mount Diablo buckwheat and researching the role of disturbance (landslide and animal use) and competition in the maintenance of the only known population. When I am not busy with research projects, I might be found anywhere in California or the western United States collecting plants or adventuring.    
 
 
  Stephanie Stuart Stephanie Stuart  —  I am using the herbaria's collections of different species of modern Azolla, a water fern, to help build a morphological phylogeny of plants from this genus. Although my work focuses on fossil specimens from the University of California Paleontology Museum, access to a wide range of modern specimens is crucial if I am to identify the fossil plants and place them in an evolutionary context. I have also used specimens from the herbarium in teaching students to identify plants — students really appreciate being able to see flowers, fruit and other reproductive structures at any time of year.    
 
 
  Hornwort Rebecca Welch  —  I am interested in the evolution of the full range of symbiotic interaction, from virulence to cooperation. Bryophyte hornworts in the genera Anthoceros and Phaeoceros, and their cyanobacterial symbiont, Nostoc are my study organisms. What are the evolutionary dynamics of intimately interacting species at the molecular level? What role do ecological factors such as community structure and life history strategies play in those dynamics? In particular, do different hornwort reproduction strategies (vegetative vs. sexual) result in differing co-evolutionary outcomes for their respective Nostoc partners?    
 
 
  Elizabeth H. Zacharias Elizabeth H. Zacharias  —  My dissertation research investigates the evolutionary, biogeographical, and ecological history of North American members of the saltbush genus Atriplex (Chenopodiaceae) and related genera. Using both field- and laboratory-based data I am integrating molecular phylogenetic methods with ecological and physiological data to understand the processes and patterns of plant evolution. Atriplex provides an extraordinary opportunity for comparative evolutionary studies; Atriplex taxa exhibit important ecological and physiological diversity, with many taxa appearing well adapted to stresses such as high temperature, limited water supply, and high salinity. Besides contributing to a better understanding of evolutionary relationships and processes, the phylogenetic framework allows me to test hypotheses about physiological and morphological change in an ecological context, such as the evolution of C3 and C4 photosynthesis, the origin of arid systems, and the evolution of salinity tolerance in angiosperm diversification. I am especially interested in how physiological differences among plants contribute to evolutionary divergence.    
 
 
  Amy Zanne Amy Zanne  —  I work at the crossroads of plant ecology, physiology, and evolutionary biology. I am interested in determining suites of plant functional traits (ecological, morphological, and physiological) and how these suites allow species to grow in different environments. I especially enjoy examining these suites in a phylogenetic context and view that such analyses can give us enhanced insight into interspecific differences. I have been examining relationships between plant physiological and anatomical traits. In this work, I am relating hydraulic safety and efficiency traits in Australian woody angiosperms between sites contrasting in nutrients and rainfall. This work entails measuring hydraulic conductivity, vulnerability to embolism, and various anatomical and leaf traits. Additionally, I am comparing species from global databases of wood anatomy traits related to hydraulic safety and efficiency.