Phylogenetic relationships within the Western United States species of Lepidium l.

Thesis (Ph.D.) University of Alaska Fairbanks, 2019The genus Lepidium L. is one of two global genera in the Brassicaceae. The genus has been arranged by species (geographic regions) worldwide, but no formal levels below the genus are recognized. Recent efforts to evaluate phylogenetic relationships have been performed at the global scale for about 20 percent of the species in the genus. The genus is recognized as having subtle and variable morphological characteristics to define species limits. Several nuclear and chloroplast DNA methods have been used to construct phylogenetic relationships within the genus. Incongruences between various phylogenetic trees indicate likely hybridization and/or hybrid origin of multiple species and a genus blurred with a reticulate evolutionary past. Internal Transcribed Spacer (ITS) ribosomal DNA (rDNA) sequences were developed here and combined with other ITS sequences on Genbank for other North American species of Lepidium. Two phylogenetic trees were developed, one comparing North American and another dominated by Intermountain West species. Results of a limited Intermountain Lepidium phylogenetic tree were compared to a cladistic tree developed from 123 morphological traits for select species of Lepidium from the western United States. A comprehensive ITS tree was developed to evaluate species relationships in the genus throughout this region. Ploidy levels of 22 taxa of Intermountain species of Lepidium were evaluated to assess whether ploidy levels were associated with any geographic or morphologic patterns within the group. The results show closely related species and varieties with several ploidy levels, but are lacking any relationships to morphological features. Neither ITS nor ploidy levels provided a clear understanding into the current taxonomic treatment of the many faint morphologically different taxa in the group. But Intermountain Lepidium, as a geographic group and clade, is distinct from other west coast members in the genus. The species most associated with all the radiant speciation, and the least understood, is L. montana.General introduction -- Chapter 1: An overview of phylogenetic relationships within the Western United States species of Lepidium l. -- Chapter 2: Genomic size and ploidy level patterns of intermountain West Lepidium using flow cytometry -- Chapter 3: Phylogenetic survey of the intermountain west members of the genus Lepidium l. (Brassicaceae) in the United States -- General conclusions

Do Genetic Differences Explain the Ability of an Alkaline Shrub to Grow in Both Uplands and Wetlands?

The hydrophyte Allenrolfea occidentalis (S. Watson) Kuntze (iodinebush) is a halophytic shrub of the arid southwest that is listed as a facultative wetland species on the National Wetland Plant List. This rating means that the species is usually a hydrophyte but occasionally is found in uplands. We tested for genetic (ecotypic) differences between plants sampled from wetlands versus uplands. We used the technique of genotyping by sequencing to generate data from 132 plants from 30 locations representing both wetland and upland occurrences for over 1300 loci. Analyses indicated that the strongest genetic signal is from differences in geographic distribution: samples that are in close geographic proximity tend to be more similar genetically regardless of whether they occur in wetland or upland locations. We detected no effect of habitat on overall genetic structure, and we found only 2 (of the 1381) loci with a positive association between genotype and habitat; in both cases the association was very weak. We infer that A. occidentalis occurrences near or in wetlands are not influenced by significant differences in genetics, and we find no evidence for wetland and upland ecotypes of this species

How Many Tree Species of Birch Are in Alaska? Implications for Wetland Designations

Wetland areas are critical habitats, especially in northern regions of North America. Wetland classifications are based on several factors, including the presence of certain plant species and assemblages of species, of which trees play a significant role. Here we examined wetland species of birch (Betula) in North America, with a focus on Alaska, and the use of birche tree species in wetland delineation. We sampled over 200 trees from sites, including Alaska, Alberta, Minnesota, and New Hampshire. We used genetic data from over 3000 loci detected by restriction site associated DNA analysis. We used an indirect estimate of ploidy based on allelic ratios and we also examined population genetic structure. We find that inferred ploidy is strongly associated with genetic groupings. We find two main distinct groups; one found throughout most of Alaska, extending into Alberta. This group is probably attributable to Betula kenaica, Betula neoalaskana, or both. This group has a diploid genetic pattern although this could easily be a function of allopolyploidy. The second major genetic group appears to extend from Eastern North America into parts of southeastern Alaska. This group represents Betula papyrifera, and is not diploid based on allelic ratios. Published chromosome counts indicate pentaploidy. Because B. papyrifera is the only one of the above species that is distinctly associated with wetland habitats, our findings indicate that tree species of birch found in most parts of Alaska are not reliable indicators of wetland habitats. These results help to support stronger wetland ratings assigned to the tree species of birch for delineation purposes

Selecting and Testing Cryptogam Species for Use in Wetland Delineation in Alaska

To support the determination of hydrophytic vegetation in wetland delineations in Alaska, USA, a series of tests were conducted to develop a group of “test positive” species to be used in a “cryptogam indicator.” In 2004, non-vascular cryptogam species (bryophytes, lichens, and fungi) from Interior and South-Central Alaska in the vicinities of Fairbanks and Anchorage were collected at a series of ten 50 × 50 cm plots along two 30 m transects in each of six upland and five wetland sites. Nineteen moss and liverwort species were selected from 86 species surveyed to test for wetland fidelity. In 2005, a plot-based analysis of frequency and cover data yielded a revised list of 17 bryophyte species that were specific to wetland communities dominated by black spruce, Picea mariana (P. Mill.) B.S.P. Fungi and lichens were found to be inadequate wetland indicators in the sampled locations because the lichen species were sparsely distributed and the fungi were too ephemeral. The cryptogam indicator was thus restricted to bryophytes. Also in 2005, bryophytes were analyzed for their presence on microtopographic positions within the landscape, including tops of hummocks and hollows at the bases of hummocks. Upland bryophyte species were found on hummock tops inside the wetland boundary, but were not abundant in the hollows (p < 0.05). The fidelity of the species selected for use in the cryptogam indicator was tested. It was determined that if more than 50% of all bryophyte cover present in hollows is composed of one or more of the 17 wetland bryophytes tested in 2005, then vascular vegetation can be considered to be hydrophytic (p < 0.001).Afin d’étayer la présence de végétation hydrophytique dans les délimitations de zones humides de l’Alaska, aux États-Unis, une série de tests a été effectuée dans le but d’aboutir à un groupe d’espèces « de test positives » à utiliser avec un « indicateur de sporophyte ». En 2004, des espèces de sporophytes non vasculaires (bryophytes, lichens et champignons) de l’intérieur et du centre-sud de l’Alaska, aux environs de Fairbanks et d’Anchorage, ont été recueillies à une série de dix parcelles de 50 sur 50 cm le long de deux transects de 30 m dans chacun de six sites montagnards et de cinq sites humides. Dix-neuf espèces de mousse et d’hépatiques ont été choisies à partir de 86 espèces prélevées dans le but d’en déterminer la fidélité aux zones humides. En 2005, une analyse de fréquence de parcelles et des données de couverture ont permis d’obtenir la liste révisée de 17 espèces de bryophytes propres aux zones humides dominées par l’épinette noire, Picea mariana (P. Mill.) B.S.P. Nous avons constaté que les champignons et les lichens étaient des indicateurs de zones humides inadéquats aux sites échantillonnés parce que les espèces de lichen étaient réparties maigrement et que les champignons étaient trop éphémères. Par conséquent, l’indicateur de sporophytes a été restreint aux bryophytes. Également en 2005, nous avons analysé les bryophytes afin d’en déterminer la présence à des positions microtopographiques du paysage, ce qui comprenait le sommet de hummocks et les creux à la base de hummocks. Des espèces de bryophytes montagnardes ont été décelées aux sommets de hummocks à l’intérieur de la limite des zones humides, mais celles-ci n’abondaient pas dans les creux (p < 0.05). La fidélité des espèces choisies afin d’être utilisées dans l’indicateur de sporophytes a été testée. Nous avons déterminé que si plus de 50 % de toute la couverture de bryophyte présente dans les creux est composée de l’une ou plusieurs des 17 bryophytes de zones humides testées en 2005, la végétation vasculaire peut alors être considérée comme hydrophytique (p < 0,001)

A RE-EVALUATION OF PHYSARIA DIDYMOCARPA VAR. INTEGRIFOLIA (CRUCIFERAE)

Volume: 31Start Page: 203End Page: 20

EVALUATION OF VARIETIES IN STANLEYA PINNATA (CRUCIFERAE)

Volume: 43Start Page: 684End Page: 68

Specific Status for Trifolium haydenii var. barnebyi (Fabaceae)

Volume: 28Start Page: 188End Page: 19

A NEW VARIETY OF PENSTEMON FREMONTII (SCROPHULARIACEAE) FROM COLORADO

Volume: 37Start Page: 195End Page: 19

ADDITIONS TO THE VASCULAR FLORA OF MONTANA AND WYOMING

Volume: 42Start Page: 413End Page: 41