rdf-syntax-grammar
mods:
  schema location: http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
  title info:
    non sort: A
    title: tale of two cacti
    sub title: studies in Astrophytum asterias and Lophophora williamsii
  name:
    name part: Terry, Martin Kilman
    name part: 1947-
    role:
      role term: creator
  name:
    name part: Pepper, Alan E.
    role:
      role term: thesis advisor.
  name:
    name part: Manhart, James R.
    role:
      role term: thesis advisor.
  type of resource: text
  genre: bibliography
  origin info:
    place:
      place term: txu
    date issued: 2007
    issuance: monographic
  language:
    language term: eng
  physical description:
    form: electronic
    form: remote
  abstract: Astrophytum asterias (star cactus) and Lophophora williamsii (peyote) are sympatric species in the Tamaulipecan thornscrub of South Texas and adjacent Mexico. Peyote has been excavated from two archaeological sites: Shumla Caves, Texas, and CM-79 in Coahuila. We report new radiocarbon dates: a mean of 5195 ± 20 ¹⁴C years BP for the Shumla Caves specimens, and 835 ± 35 ¹⁴C years BP for the CM-79 specimen. The Shumla Caves specimens were not intact peyote tops, but manufactured effigies thereof. Published data on the geographic ranges of L. williamsii and A. asterias are of varying quality and accuracy. We report the results of extensive research to document extant U.S. populations by county, drawing specific conclusions about where each species currently occurs, where its occurrence is uncertain and where it is unlikely, based on herbarium specimens, verifiable reports in the primary literature and interviews with knowledgeable individuals. Dwindling of populations of peyote is partly due to improper harvesting, namely cutting off the top of the plant so deeply below ground level that the plant is unable to regenerate new stems, and consequently dies. We describe the anatomy of the cactus shoot (stem) and root, and suggest how this new knowledge can be utilized to determine "how deep is too deep" to cut if harvesting of peyote is to be done sustainably. We report the first population genetics study on endangered A. asterias, with five microsatellite markers in populations sampled at four locations in South Texas. A battery of tests and measurements indicated that in most populations heterozygosity was high, F-statistics were low, and Nm was >1. With one exception, these populations appear not to be undergoing excessive inbreeding, despite small population sizes. Data from two L. williamsii microsatellite loci are presented. L. williamsii, which reproduces autogamously, exhibits a single homozygous genotype within a given population. West Texas L. williamsii plants di…
  note: by Martin Kilman Terry.
  note: "Major Subject: Botany"
  note: Title from author supplied metadata (automated record created on Apr. 27, 2007.)
  note: Vita.
  note: Abstract.
  note: Electronic resource.
  note: Mode of access: World Wide Web.
  note: System requirements: World Wide Web access and Adobe Acrobat Reader.
  note: Ph. D. Texas A&M University 2005.
  note: Includes bibliographical references.
  note: Text (Dissertation).
  subject:
    topic: Major Botany
  subject:
    topic: Astrophytum asterias
  subject:
    topic: Lophophora williamsii
  subject:
    topic: archaeobotany
  subject:
    topic: population genetics
  subject:
    topic: cactus conservation
  identifier: http://hdl.handle.net/1969.1/5023
  record info:
    record content source: TXA
    record creation date: 070607
    record change date: 20151105052751.0
    record identifier: in00002252533