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  • A fistful of Astragalus : phenotypic and genotypic basis of the most taxon rich species in the North American flora

    Creator:
    Knaus, Brian J.
    Abstract:
    The study of the infra-specific ranks (i.e., subspecies and variety) can be considered the study of the process of speciation. Astragalus lentiginosus Douglas ex Hooker (Fabaceae) is the most taxon rich species in the U.S. flora currently including 40 taxonomic varieties. These varieties were described using traditional taxonomic methods primarily...
    Resource Type:
    Dissertation
    Full Text:
    freckles. This legume is distributed primarily throughout the intermountain region of North America

  • Origin and distribution of polyploid Achillea (Compositae) in western North America

    Creator:
    Tyrl, Ronald J.
    Abstract:
    A cytogeographical study was made of populations of tetraploid (n=18) and hexaploid (n=27) Achillea millefolium (Compositae- Anthemideae) from the Pacific Coast states. There is a complex distributional pattern, involving overlapping ranges, mixed populations, migration of one form into areas occuplied by the other, pentaploid hybrids, and septaploid and octoploid plants....
    Resource Type:
    Dissertation
    Full Text:
    -in-Aid of Research from the Society of the Sigma. Xi. TABLE OF CONTENTS Page INTRODUCTION 1

  • Studies on the etiology and epidemiology of bull's eye rot of pears

    Creator:
    Henriquez, Jose Luis, 1961-
    Abstract:
    The objective of this dissertation is to introduce low-cost processing methods for the fabrication of ZnO transparent thin-film transistors (TTFTs). A novel method for depositing ZnO body layers via spin-coating of a zinc nitrate-based spin solution is presented. The processing conditions of spin-coated ZnO are optimized to produce continuous and...
    Resource Type:
    Dissertation
    Full Text:
    also associated with the disease in the East coast of North America (Lockhart and Ross, 1961; de Jong

  • Population viability analysis of endangered plant species : an evaluation of stochastic methods and an application to a rare prairie plant

    Creator:
    Kaye, Thomas N.
    Abstract:
    Transition matrix models are one of the most widely used tools for assessing population viability. The technique allows inclusion of environmental variability, thereby permitting estimation of probabilistic events, such as extinction. However, few studies use the technique to compare the effects of management treatments on population viability, and fewer still...
    Resource Type:
    Dissertation
    Full Text:
    . The Native Plant Society of Oregon helped finance conservation biology interns that assisted with

  • Effects of single and multiple stressors on communities of wheat and wild oats

    Creator:
    Pfleeger, Thomas G.
    Abstract:
    Most plant toxicology tests developed in support of environmental laws use a single stress applied to an individual plant. While tests using individual species or stresses require fewer resources and are easier to interpret, they are under increasing criticism for being unrealistic and missing important ecological interactions. The objective of...
    Resource Type:
    Dissertation
    Full Text:
    wheat and wild oats AN ABSTRACT OF THE THESIS OF Thomas G. Pfleeger for the degree of Doctor of

  • The influence of prescribed fire on the rare endemic plant Delphinium pavonaceum (Peacock larkspur)

    Creator:
    McKernan, Brie-Anne
    Abstract:
    In the wetland prairie of William L. Finley National Wildlife Refuge (FNWR) in western Oregon, we investigated the response of Delphinium pavonaceum Ewan (peacock larkspur, Ranunculaceae), an endangered perennial forb, to four unreplicated dormant season fire regimes of 0, 2, 4, or 10 fires that were applied over a 12-year...
    Resource Type:
    Masters Thesis
    Full Text:
    grants from the Bonnie C. Templeton Endowment and the Corvallis Chapter of the Native Plant Society of

  • Effects of fire on seedling establishment in upland prairies in the Willamette Valley, Oregon

    Creator:
    Maret, Mary P.
    Abstract:
    Prior to European settlement, native prairie dominated the landscape of the Willamette Valley. Today, due to urbanization, agriculture, and the cessation of burning, only isolated remnants of these grasslands still exist. In response to conservation concerns, there has been a move to restore the remaining prairies in the Willamette Valley,...
    Resource Type:
    Masters Thesis
    Full Text:
    component in the development and maintenance of most grassland communities in North America (Vogl 1974

  • Unearthing the Cretaceous Diversification of Cornales

    Creator:
    Atkinson, Brian A.
    Abstract:
    The order Cornales (dogwoods) is the earliest diverging lineage within the most diverse group of flowering plants, the asterids (>80,000 species). Although molecular phylogenetics have significantly improved our understanding of cornalean systematics, early phylogenetic relationships remain uncertain due to an initial rapid radiation. The fossil record of Cornales is extensive...
    Resource Type:
    Dissertation
    Full Text:
    Paleobotany and the Paleobotanical Section of the Botanical Society of America. Thanks to Pankaj Jaiswal for

  • Performance of Willamette Valley native plants following herbicide exposure

    Creator:
    Blakeley-Smith, Matthew R.
    Abstract:
    Prairies were once the dominant vegetation type in Oregon's Willamette Valley. Land use conversion, fire suppression, succession, and invasive species have reduced Willamette Valley prairies to less than 1% of their historical area. The remnant prairies that persist today are small in size and are highly fragmented. Marginal strips of...
    Resource Type:
    Masters Thesis
    Full Text:
    AN ABSTRACT OF THE THESIS OF Matthew R. Blakeley-Smith for

  • Phylogeny, cospeciation, and host switching in the evolution of the ascomycete genus Rhabdocline on Pseudotsuga and Larix (Pinaceae)

    Creator:
    Gernandt, David S.
    Abstract:
    The relative role of cospeciation and host switching in the phylogenetic history of ascomycete foliar symbionts is addressed in the orders Leotiales and Rhytismatales, fungi associated predominantly with Pinaceae (Coniferales). Emphasis is placed on comparing the evolution of the sister genera Pseudotsuga and Larix (Pinaceae) with that of the pathogenic...
    Resource Type:
    Dissertation
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    grandmother, Frances Cavoretto. The Mycological Society of America awarded me several travel grants to their