The Phoenix Zoo, also known as the Arizona Center for Nature Conservation (PZ), is an Association of Zoos and Aquariums (AZA) accredited zoological institution and among largest-nonprofit, privately-owned zoos in the United States (Smith, 2020). Located within Papago Park in Phoenix (Maricopa County), Arizona, adjacent to the Desert Botanical Garden (DES), the two combine to bring environmental awareness to the Phoenix Metropolitan Region. While the DES specializes in botanical presentation, the ACNC focuses on zoological education. Whereas the flora of DES is well known, that of ACNC has yet to be completely documented. Given its role as a center for public engagement and education, documenting and mapping the floristic diversity of the Phoenix Zoo provides updated botanical information and occurrence records, an important component of understanding biodiversity for the Phoenix area. Between the fall of 2017 and the Spring of 2021, the grounds of the ACNC were walked within the 2-mile perimeter and surrounding exterior within Papago Park. Plant specimens and photographs were collected and archived for later identification using various botanical keys. Species names were verified through updated botanical databases such as Tropicos.org and worldfloraonline.org and compiled into a checklist. A total of 706 species have been identified, and of those 548 specimens have been collected as specimen vouchers. Of these, 120 are of taxa known to be native to the Phoenix Salt River Valley. While approximately 79 of those previously listed taxa native to Papago Park were either not found during this study or were extirpated from the grounds of the ACNC during urbanization of the region. There are 586 exotic taxa, some are common cultivars, while others are new to the region. Data for this survey is publicly available on SEINet, a regional network of North America herbaria (https://swbiodiversity.org/seinet/), as georeferenced voucher specimens, human observations, and photographs. Data is also partially duplicated through the iNaturalist platform (iNaturalist.com).

For this study, the flora of the northern section of the Lower Verde River, within the Tonto National Forest in Yavapai and Gila Counties, Arizona was documented and analyzed. The study site, part of the northern leading edge of the Sonoran Desert, encompasses about 16,000 hectares and is located approximately 45 miles north-northeast of Phoenix. The area, extends roughly 28 river miles from the East Verde River in the north to Chalk Mountain in the south and is largely only accessible by foot, or by boat, and as a result was previously extremely under-collected. Over a three-year study period, from August, 2017 to May, 2020, 835 plant specimens were collected and identified, representing 360 species which, combined with earlier herbarium specimens collected by others, resulted in 427 plant species found in the study area. The plant diversity of this remote region reflects three distinct vegetation communities: upland Sonoran Desert, perennial riparian corridor, and semi-desert grasslands. Together, these communities act as an important transition zone between the Sonoran Desert and higher elevation habitats. Perennial streams are biodiversity hotspots within the study area. For example, the 400 hectares of Red Creek that falls within the study boundaries contain 28% of the total species. The study site contains several plants of conservation importance including 12 species endemic to Arizona, 22 vulnerable or imperiled species, five US Forest Service sensitive species, and one Federally Endangered species. In order to compare the diversity of the Lower Verde River Flora to nine other similar/related floras in Arizona, a species-area curve using five different models was generated. The resulting models showed the Lower Verde River flora to be very close to, although slightly below, the species-accumulation curve which may indicate that roughly 50-100 species may yet be added to the flora. This prediction seems realistic, as there were several locations that could not be collected due to remoteness and excessive heat.

Las Cienegas National Conservation Area (LCNCA), located in southeastern Arizona, is a place of ecological and historical value. It is host to rare native, threatened and endangered fauna and flora. as well as the site of the oldest operating ranch in the state. The first chapter of this thesis provides a preliminary flora of vascular plants at LCNCA assembled from field collections, photographs and herbarium specimens, and published through the online database SEINet. This preliminary flora of LCNCA identified 403 species in 76 families. Less than 6% of the flora is non-native, perennial forbs and grasses are the most abundant groups, and over a third of species in the checklist are associated with wetlands. LCNCA has been the target of adaptive management and conservation strategies to preserve its biotic diversity, and results from this study will help inform actions to preserve its rare habitats including cottonwood willow forests, mesquite bosques, sacaton grasslands, and cienegas. The second chapter investigates poorly understood aspects of the life history of the endangered Huachuca Water Umbel (Lilaeopsis schaffneriana subsp. recurva. Apiaceae) (hereafter HWU). This wetland species occurs in scattered cienegas and streams in southeastern Arizona and northern Sonora, Mexico. Three studies were conducted in a greenhouse to investigate seed bank establishment, seed longevity, and drought tolerance. A fourth study compared the reproductive phenology of populations transplanted at LCNCA to populations transplanted at urban sites like the Phoenix Zoo Conservation Center and the Desert Botanical Garden (DBG). Results from the greenhouse studies showed that HWU seeds were capable of germinating 15 years in a dormant state and that HWU seeds are present in the seed banks at sites where populations have been transplanted. Also, greenhouse experiments indicated that colonies of HWU can tolerate up to 3 weeks without flowing water, and up to 2 weeks in dry substrate. Transplanted populations at LCNCA monitored in the fourth study produced a higher abundance of flowers and fruit relative to urban sites (i.e. DBG) suggesting that in-situ conservation efforts may be more favorable for the recovery of HWU populations. Findings from these studies aim to inform gaps in knowledge highlighted in USFWS recovery plan for this species.

Baseline community composition data provides a snapshot in time that allows changes in composition to be monitored more effectively and can inform best practices. This study examines Arizona Upland plant community composition of the Sonoran Desert through three different lenses: floristic inventory, and fire and reseeding effects.

A floristic inventory was conducted at Cave Creek Regional Park (CCRP), Maricopa County, AZ. One hundred fifty-four taxa were documented within Park boundaries, including 148 species and six infraspecific taxa in 43 families. Asteraceae, Boraginaceae, and Fabaceae accounted for 40% of documented species and annuals accounted for 56% of documented diversity.

Fire effects were studied at three locations within McDowell Sonoran Preserve (MSP), Scottsdale, AZ. These fires occurred throughout the 1990s and recovered naturally. Fire and reseeding effects were studied at the site of a 2005 fire within CCRP that was reseeded immediately following the fire.

Two questions underlie the study regarding fire and reseeding effects: 1) How did fire and reseeding affect the cover and diversity of the plant communities? 2) Is there a difference in distribution of cover between treatments for individual species or growth habits? To address these questions, I compared burned and adjacent unburned treatments at each site, with an additional reseeded treatment added at CCRP.

MSP sites revealed overall diversity and cover was similar between treatments, but succulent cover was significantly reduced, and subshrub cover was significantly greater in the burn treatment. Seventeen species showed significant difference in distribution of cover between treatments.

The CCRP reseeded site revealed 11 of 28 species used in the seed mix persist 12 years post-fire. The reseeded treatment showed greater overall diversity than burned and unburned treatments. Succulent and shrub cover were significantly reduced by fire while subshrub cover was significantly greater in the reseeded treatment. Sixteen species showed significant difference in distribution of cover between treatments.

Fire appears to impact plant community composition across Arizona Upland sites. Choosing species to include in seed mixes for post-fire reseeding, based on knowledge of pre-fire species composition and individual species’ fire responses, may be a useful tool to promote post-fire plant community recovery.

The remarkable conservation of molecular and intra-/inter-cellular pathways underpinning the fundamental aspects of sugar partitioning in two evolutionarily divergent organisms – a non-vascular moss Physcomitrella patens and a vascular cereal crop Oryza sativa (rice) – forms the basis of this manuscript. Much of our current knowledge pertaining to sugar partitioning in plants mainly comes from studies in thale cress, Arabidopsis thaliana, but how photosynthetic sugar is loaded into the phloem in a crop as important as rice is still debated. Even less is known about the mechanistic aspects of sugar movement in mosses. In plants, sugar either moves passively via intercellular channels called plasmodesmata, or through the cell wall spaces in an energy-consuming process. As such, I first investigated the structure of plasmodesmata in rice leaf minor vein using electron tomography to create as of yet unreported 3D models of these channels in both simple and branched conformations. Contrary to generally held belief, I report two different 3D morphotypes of simple plasmodesmata in rice. Furthermore, the complementary body of evidence in arabidopsis implicates plasma membrane localized Proton Pyrophosphatase (H+-PPase) in the energy-dependent movement of sugar. Within this wider purview, I studied the in situ ultrastructural localization patterns of H+-PPase orthologs in high-pressure frozen tissues of rice and physcomitrella. Were H+-PPases neo-functionalized in the vascular tissues of higher plants? Or are there evolutionarily conserved roles of this protein that transcend the phylogenetic diversity of land plants? I show that H+-PPases are distinctly expressed in the actively growing regions of both rice and physcomitrella. As expected, H+-PPases were also localized in the vascular tissues of rice. But surprisingly, H+-PPase orthologs were also prominently expressed at the gametophyte-sporophyte junction of physcomitrella. Upon immunogold labeling, H+-PPases were found to be predominantly localized at the plasma membrane of the phloem complexes of rice source leaves, and both the vacuoles and plasma membrane of the transfer cells in the physcomitrella haustorium, linking H+-PPases in active sucrose loading in both plants. As such, these findings suggest that the localization and presumably the function of H+-PPases are conserved throughout the evolutionary history of land plants.

This dissertation research investigates both spatial and temporal aspects of Bronze Age land use and land cover in the Eastern Mediterranean using botanical macrofossils of charcoal and charred seeds as sources of proxy data. Comparisons through time and over space using seed and charcoal densities, seed to charcoal ratios, and seed and charcoal identifications provide a comprehensive view of island vs. mainland vegetative trajectories through the critical 1000 year time period from 2500 BC to 1500 BC of both climatic fluctuation and significant anthropogenic forces. This research focuses particularly on the Mediterranean island of Cyprus during this crucial interface of climatic and human impacts on the landscape. Macrobotanical data often are interpreted locally in reference to a specific site, whereas this research draws spatial comparisons between contemporaneous archaeological sites as well as temporal comparisons between non-contemporaneous sites. This larger perspective is particularly crucial on Cyprus, where field scientists commonly assume that botanical macrofossils are poorly preserved, thus unnecessarily limiting their use as an interpretive proxy. These data reveal very minor anthropogenic landscape changes on the island of Cyprus compared to those associated with contemporaneous mainland sites. These data also reveal that climatic forces influenced land use decisions on the mainland sites, and provides crucial evidence pertaining to the rise of early anthropogenic landscapes and urbanized civilization.

Acceptance of the plant group Martyniaceae as a distinct family has long been questioned. Previously placed in the family Pedaliaceae, the Martyniaceae have been allied to numerous other families within the order Lamiales. The objectives of this study include the investigation of the placement of the Martyniaceae within the order Lamiales using molecular data (chloroplast DNA sequences), the further examination of the internal relationships of the Martyniaceae using an expanded nuclear and chloroplast sequences data set, and the construction of a taxonomic treatment of the family that includes all published names and taxa in the Martyniaceae. An analysis of the Lamiales using two chloroplast gene regions (ndhF and rps16) reveals that the Martyniaceae should be segregated from the family Pedaliaceae, but is not able to support the placement of any of its putatively-related families as sister to the Martyniaceae. Sequences from 151 taxa of the Lamiales are included in the analysis, including six representatives from the Martyniaceae. An analysis of the Martyniaceae using three chloroplast gene regions (psbA-trnH spacer, trnQ-5'rps16 intergenic spacer, and trnS-trnG-trnG spacer and intron) and the Internal Transcribed Spacer resolves two major clades within the Martyniaceae corresponding to the North American taxa (Martynia and Proboscidea) and the South American taxa (Craniolaria, Holoregmia, and Ibicella). Sequences from all five genera and 15 taxa were included in the analysis. Results from the molecular phylogenetic analyses are incorporated into a revised taxonomic treatment of the family. Five genera and thirteen species are recognized for the family Martyniaceae.

The Juglandaceae (walnuts, hickories, pecans) has one of the best-documented fossil records in the Northern Hemisphere. The oldest modern genus, Cyclocarya, today restricted to China, first appears in the late Paleocene (57 ma) of North Dakota, USA. Unlike walnuts and pecans that produce edible fruits dispersed by mammals, Cyclocarya fruits are small nutlets surrounded by a prominent circular wing, and are thought to be wind- or water-dispersed. The current study provides the first evidence that fossil fruits were different from modern forms in the number and organization of their attachment to reproductive branches, and in their anatomical structure. Unlike the modern genus that bears separate pistillate and staminate flowers the fossil fruits had attached pollen-bearing structures. Unisexual pollen catkins are also present, suggesting the fossil Cyclocarya may have differed from its modern relative in this feature. Like several other plants from the late Paleocene Almont/Beicegel Creek floras, Cyclocarya shows a mosaic combination of characters not seen in their modern counterparts. Fossils were collected from the field, and examined for specimens exposed on the weathered rock surface. Specimens from Almont were photographed with reflected light, while those from Beicegel Creek cut into slabs and prepared by etching the rock matrix in 49% hydrofluoric and re-embedding the exposed plant material in cellulose acetate and acetone to make "peels". Selected specimens are cut out, mounted on microscope slides, and studied with light microscopy. These fossil fruits were studied because they are the earliest fossil evidence of Cyclocarya. They are exceptionally preserved and thus provide critical structural evidence for changes in that occurred during the evolution of plants within this lineage. Because Cyclocarya fruits are winged, they might be assumed to be wind-dispersed. Their radial symmetry does not have the aerodynamic qualities typical of wind-dispersed fruits, and may have been dispersed by water.