Systematics Section / ASPT
Busby, Lisa D. , Burr, Kirsti A. , Johnson, Leigh A. .
Relationships and reticulation among the vernal pool navarretias (Polemoniaceae).
Navarretia section Navarretia circumscribes 10 species (17 taxa) largely specialized to vernal pools, ephemeral wetlands, or otherwise seasonally moist habitats. Because half of these taxa are considered vernal pool endemics and several are known from only one or a few locations, section Navarretia comprises the single greatest phylogenetic concentration of species of concern in tribe Gilieae, if not Polemoniaceae, as a whole. Prior phylogenetic work based on morphology and nuclear ITS sequences supports the monophyly of section Navarretia, but provided only incomplete resolution of relationships within this clade. To provide a framework for exploring further the evolutionary aspects of vernal pool specialization and genetic relationships among populations of the narrowly endemic taxa, we undertook this study to test hypotheses of species boundaries and interspecific relationships. Our sampling includes multiple populations of most taxa from geographic disparate localities, using both multiple chloroplast loci and cloned ITS haplotypes. Our results suggest Navarretia propinqua, long considered a variety or subspecies of N. intertexta, may in fact be an allopolyploid derivative of N. intertexta and N. saximontana. The progenitors of N. fossalis and N. willamettensis may also have experienced introgression and chloroplast capture prior to the geographic spread of these species. Although these hypotheses are well supported, additional work is yet needed to understand the evolutionary dynamics among species and populations, particularly within the monophyletic "vernal pool specialist" subclade of section Navarretia.
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1 - Brigham Young University, Integrative Biology, 401 Widstoe Building, Provo, Utah, 84602, USA
2 - Brigham Young University, Integrative Biology, 401 Widtsoe Building, Provo, Utah, 84602, USA
3 - Brigham Young University, Department of Integrative Biology, 401 Widtsoe Building, Provo, Utah, 84602, USA
Presentation Type: Poster:Posters for Sections
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM