Doctor of Philosophy, The Ohio State University, 2003, Evolution, Ecology, and Organismal Biology

Zaluzianskya (Scrophulariaceae s.s., tribe Manuleeae) is a southern African genus with four sections, whose floral diversity is particularly evident. This work examines Zaluzianskya at population and genus-wide levels. Sympatric and allopatric populations of Z. microsiphon (day-flowering) and Z. natalensis (night-flowering) were examined using ISSR markers in combination with ordination analyses of morphology. Although unexpected due to differences in flowering time between these species, putative hybrids have been found. The high genetic similarity between these species made it difficult to recover patterns of gene flow. However, it appears that genetic material from Z. microsiphon may be introgressing into Z. natalensis. The first broad phylogenies for Zaluzianskya were resolved using nuclear (ITS) and chloroplast (rpl16 and trnL-trnF) sequences. Analyses of separate and combined data sets were largely congruent, resolving three main clades. The only significant incongruence involved the single species included from section Macrocalyx. This species is placed sister to section Nycterinia by ITS but within that section by cpDNA. Consequently, the monophyly of section Nycterinia is undecided. It is certain, however, that sections Zaluzianskya and Holomeria are not monophyletic. Additionally, one of the purported outgroups (Reyemia) was nested within Zaluzianskya with strong support. Based on this and morphological affinity, this ditypic genus should be submerged within Zaluzianskya. Finally, the status of Z. microsiphon is uncertain, with three populations clearly separated in the phylogeny. Potentially this represents three lineages with convergent morphology due to pollinator selection. Alternatively, hybridization may have distorted Z. microsiphons placement on the phylogeny. Character evolution was also examined, to find morphological synapomorphies for the new infrageneric groups and to consider the evolution of floral diversity within Zaluzianskya. Several trai (open full item for complete abstract)

Committee: Andrea Wolfe (Advisor) Subjects:

Doctor of Philosophy (PhD), Ohio University, 2005, Biological Sciences (Arts and Sciences)

Viola flettii, Viola cuneata and Viola ocellata are sister species within the Viola canadensis complex (Violaceae). All are endemics of western North America, growing in widely divergent ecological environments. During the summers of 1998, 1999, 2001 and 2002, leaf material for DNA extraction was collected from 26 populations of the three species, including much of their range. Analysis of V. flettii DNA using intersimple sequence repeat (ISSR) markers showed a great deal of diversity with percent polymorphic loci (P) of 65% and a disjunction between northern and southern populations. Statistical analysis of collected ecological data from V. flettii indicated a microhabitat effect of greater elevation and more southernly aspect leading to lowered genetic diversity and population size, respectively. Preserving the genetic diversity in V. flettii by protecting populations in both regions with emphasis on those at more optimal microhabitats will aid in maintaining the current fitness ability of this endemic species. Nested Clade Analysis (NCA) of Polymerase chain reaction - restriction fragment length polymorphisms (PCR-RFLP) data from chloroplast regions of all three species showed no distinct groupings based on taxon assignment, potentially indicating past hybridization and chloroplast capture during the early stages of speciation or subsequently and repeatedly within Pleistocene refugia harboring all three species. Contrary to the evidence suggesting hybridization and interspecific gene flow, ecological, environmental, leaf morphology and leaf angle data all show the three Viola species to be strongly distinct, supporting the idea that the three species are morphologically and ecologically well differentiated.

Committee: Harvey Ballard (Advisor) Subjects: Biology, Botany

Master of Science (MS), Ohio University, 2003, Environmental Studies (Arts and Sciences)

The purpose of this thesis was to investigate pollen-mediated gene flow and genetic variation within populations of Manfreda virginica that occur in prairie openings in Adams County, Ohio. M. virginica was chosen because of its historic co-dominance in the xeric prairies and its role as a dominant plant in globally rare limestone seep habitats. A pollen surrogate was used to estimate pollen dispersal and inferred pollen movement is frequent within populations, but not among populations. A single species of Halictid bee appears to be the primary and perhaps sole pollinator. Genetic analysis was performed using Inter-Simple Sequence Repeat (ISSR) markers. No significant relationship was found between geographic distance and genetic distance and substantial genetic variation is found between all populations regardless of size or geographic position. Heterozygosity and polymorphism was low within all populations. Analysis indicates substantial fixation of alleles within populations, perhaps driven by drift due to genetic isolation.

Committee: Harvey Ballard (Advisor) Subjects: Biology, Botany