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Molecular Phylogeny Of The Genus Houstonia And Allies In Rubiaceae, Hunter Lee Shanks
Molecular Phylogeny Of The Genus Houstonia And Allies In Rubiaceae, Hunter Lee Shanks
Biological Sciences Theses & Dissertations
Houstonia (Rubiaceae) is a strictly North American genus of 24 species distributed from Mexico, throughout the United States, up to Canada. Houstonia has proven to be a taxonomically difficult genus since the Linnaean description of Houstonia and the related genera: Hedyotis and Oldenlandia in 1753. For over 250 years botanists have lumped and separated Houstonia from Hedyotis and Oldenlandia based on various morphological characters. The most recent circumscription of Houstonia (Terrell 1996) separated the genus into two subgenera with each subgenus containing two sections. Nuclear (ITS) and plastid (trnL-F, rps16) DNA sequences were used to build a molecular phylogeny depicting …
Species Delimitation And Phylogenetic Relationships Of The Wild Yams (Dioscorea) Native To Eastern North America, Tori A. Collins
Species Delimitation And Phylogenetic Relationships Of The Wild Yams (Dioscorea) Native To Eastern North America, Tori A. Collins
Honors Theses
Most taxonomic treatments currently recognize two to three species of native yams in eastern North America: Dioscorea villosa, D. floridana, and sometimes D. quaternata, a segregate of D. villosa. Earlier authors (e.g., J. K. Small) had recognized as many as five species (with D. hirticaulis and D. glauca also as segregates of D. villosa). Key morphological features in distinguishing these putative species are rhizome morphology (long and cord-like vs. thick and contorted), number of first leaves (1–3 vs. 4–7), and habitat (sandy, rocky, swampy). Unfortunately, these critical features are rarely collected and preserved on herbarium …
Systematics And Biogeography Of Orthaea Kloztsch (Ericaceae: Vaccinieae), Nelson Salinas
Systematics And Biogeography Of Orthaea Kloztsch (Ericaceae: Vaccinieae), Nelson Salinas
Dissertations, Theses, and Capstone Projects
In the first chapter a study of the distribution patterns of the neotropical Vaccinieae (Ericaceae) is presented. Five areas of endemism were recovered: Central America, northern Chocó, southern Chocó, eastern Ecuador, and Yungas. Divergence times estimations indicate that the Andean clade of Vaccinieae migrated to South America during the Late Oligocene or Early Miocene (28.9-17.84 MA), and most of the subsequent diversification took place during the Tertiary. The Yungas was the first Andean area to be colonized, and several dispersals towards the north expanded their distribution range. Both areas of endemism and dispersal events were influenced by geological processes, such …
Evolutionary Relationships Among Fungal Soybean Pathogens And Molecular Marker Development In The Genus Cercospora, Sebastian Albu
Evolutionary Relationships Among Fungal Soybean Pathogens And Molecular Marker Development In The Genus Cercospora, Sebastian Albu
LSU Doctoral Dissertations
Cercospora leaf blight (CLB) and purple seed stain (PSS) are common soybean diseases in the Gulf South of the United States (USA). For nearly a century, Cercospora kikuchii has been considered as the only pathogen causing these diseases. However, previous reports of genetic diversity among isolates collected throughout Louisiana suggested the presence of multiple lineages or species. Recent systematic studies classified species of Cercospora using a taxonomic system based on phylogenetic analysis of five nuclear loci (legacy genes). Using a similar approach, cercosporoid fungi tentatively identified as C. kikuchii were evaluated along with 53 other species of Cercospora. No …