Conservation genomics and pollination biology of an endangered, edaphic-endemic, octoploid herb: El Dorado bedstraw ( subsp. ; Rubiaceae).

El Dorado bedstraw ( subsp. ) is a federally endangered dioecious, octoploid, perennial herb found only in the Pine Hill region of El Dorado County, CA, USA. Like many species of , El Dorado bedstraw is capable of both sexual and asexual reproduction, spreading via stem-layering as well as seeds.

Influence of a climatic gradient on genetic exchange between two oak species.

Premise: In plant groups with limited intrinsic barriers to gene flow, it is thought that environmental conditions can modulate interspecific genetic exchange. Oaks are known for limited barriers to gene flow among closely related species. Here, we use Quercus as a living laboratory in which to pursue a fundamental question in plant evolution: Do environmental gradients restrict or promote genetic exchange between species?

Methods: We focused on two North American oaks, the rare Quercus dumosa and the widespread Q.

Evolution of leaf structure and drought tolerance in species of Californian Ceanothus.

Premise Of The Study: Studies across diverse species have established theory for the contribution of leaf traits to plant drought tolerance. For example, species in more arid climates tend to have smaller leaves of higher vein density, higher leaf mass per area, and more negative osmotic potential at turgor loss point (π ). However, few studies have tested these associations for species within a given lineage that have diversified across an aridity gradient.

Leaf adaptations and species boundaries in North American Cercis: implications for the evolution of dry floras.

Premise Of The Study: The North American Cercis clade spans dry to mesic climates and exhibits complex morphological variation. We tested various proposed species classifications of this group and whether aspects of leaf morphology, particularly the "drip-tip" in some regional populations, are adaptive and/or linked with phylogeny.

Methods: We made measurements on over 1100 herbarium specimens from throughout North America and analyzed the data with univariate and multivariate approaches.

Toxicity of the spiny thick-foot Pachypodium.

Premise Of The Study: Pachypodium (Apocynaceae) is a genus of iconic stem-succulent and poisonous plants endemic to Madagascar and southern Africa. We tested hypotheses about the mode of action and macroevolution of toxicity in this group. We further hypothesized that while monarch butterflies are highly resistant to cardenolide toxins (a type of cardiac glycoside) from American Asclepias, they may be negatively affected by Pachypodium defenses, which evolved independently.

The evolutionary history of ferns inferred from 25 low-copy nuclear genes.

Unlabelled: •

Premise Of The Study: Understanding fern (monilophyte) phylogeny and its evolutionary timescale is critical for broad investigations of the evolution of land plants, and for providing the point of comparison necessary for studying the evolution of the fern sister group, seed plants. Molecular phylogenetic investigations have revolutionized our understanding of fern phylogeny, however, to date, these studies have relied almost exclusively on plastid data.•

Methods: Here we take a curated phylogenomics approach to infer the first broad fern phylogeny from multiple nuclear loci, by combining broad taxon sampling (73 ferns and 12 outgroup species) with focused character sampling (25 loci comprising 35877 bp), along with rigorous alignment, orthology inference and model selection.

Horizontal transfer of an adaptive chimeric photoreceptor from bryophytes to ferns.

Ferns are well known for their shade-dwelling habits. Their ability to thrive under low-light conditions has been linked to the evolution of a novel chimeric photoreceptor--neochrome--that fuses red-sensing phytochrome and blue-sensing phototropin modules into a single gene, thereby optimizing phototropic responses. Despite being implicated in facilitating the diversification of modern ferns, the origin of neochrome has remained a mystery.

Transcriptome-mining for single-copy nuclear markers in ferns.

Background: Molecular phylogenetic investigations have revolutionized our understanding of the evolutionary history of ferns-the second-most species-rich major group of vascular plants, and the sister clade to seed plants. The general absence of genomic resources available for this important group of plants, however, has resulted in the strong dependence of these studies on plastid data; nuclear or mitochondrial data have been rarely used. In this study, we utilize transcriptome data to design primers for nuclear markers for use in studies of fern evolutionary biology, and demonstrate the utility of these markers across the largest order of ferns, the Polypodiales.

Limited hybridization across an edaphic disjunction between the gabbro-endemic shrub Ceanothus roderickii (Rhamnaceae) and the soil-generalist Ceanothus cuneatus.

Premise Of The Study: Hybridization is thought to have played an important role in diversification of the speciose shrub genus Ceanothus; putative hybrid species have been described, and data suggest that intrinsic barriers may not exist among closely related species. However, the extent to which hybridization occurs in the wild is not known, and little is understood about how extrinsic factors such as soil chemistry may influence the process. The present research focuses on the gabbro-endemic C.

Phylogeny of the plant genus Pachypodium (Apocynaceae).

Background. The genus Pachypodium contains 21 species of succulent, generally spinescent shrubs and trees found in southern Africa and Madagascar. Pachypodium has diversified mostly into arid and semi-arid habitats of Madagascar, and has been cited as an example of a plant group that links the highly diverse arid-adapted floras of Africa and Madagascar.

Microsatellite markers from Ceanothus roderickii (Rhamnaceae) using next-generation sequencing technology.

Premise Of The Study: Ceanothus roderickii is an endangered shrub endemic to California. To investigate the population genetics of this species, including the genetic consequences of population fragmentation and hybridization, 10 microsatellite markers were developed.

Methods And Results: Using next-generation sequencing (454) data from a single C.