Rancho Santa Ana Botanic Garden

Lithium batteries are currently used in most mobile devices, electric vehicles, and utility-scale battery storage systems. The demand for lithium is expected to increase in the coming decades and understanding the potential impacts of extracting lithium on biodiversity is critically important for identifying the most appropriate places for extraction to occur. We document the potential impact of 55 proposed lithium extraction projects and broad areas identified as containing lithium reserves on the biodiversity of imperiled to vulnerable species (ranked G1-G3 and S1-S3). We identified 538,426 ha of proposed lithium project sites and adjacent impact areas in California and Nevada. Within the proposed projects areas there were 34 species ranked globally imperiled to vulnerable in California and 19 species ranked globally imperiled to vulnerable in Nevada. Broad areas identified as containing lithium reserves supported 366 species in California and 193 species in Nevada that were ranked as imperiled to vulnerable. Of the 20 most imperiled species, 85 % were wetland dependent, and seven species had 100 % of their known distribution occur within a proposed lithium project site. If the current proposed lithium projects are built, 54 globally imperiled to vulnerable species are likely to be negatively impacted in California and Nevada. These results highlight the importance of balancing conservation of biodiversity with solutions to mitigate climate change. To limit biodiversity loss, there is a need for a holistic planning process that prioritizes the lowest conflict sites for development over high conflict sites. • Global lithium demand is expected to grow rapidly in the coming decades. • Proposed lithium extraction sites threaten 20 imperiled species. • 54 species ranked imperiled to vulnerable occur on lithium project sites. • 85 % of the most imperiled species are wetland dependent.

Abstract Phylogenetics is crucial in the study of evolutionary processes and events transpiring in the course of species diversification. Phylogenetic studies within kingdom Plantae often reveal hybridization and introgression. Here, we study a subsection rife with historic hybridization and discuss the impacts of such processes on evolutionary trajectories. Aliciella subsection Subnuda comprises seven species of herbaceous plants occurring in Utah, the Navajo Nation, and the Four Corners region of North America. Previous molecular and morphological work left relationships in the subsection unresolved. Here, we use comparative DNA sequencing of nuclear ITS and chloroplast DNA regions and genome‐wide RAD‐seq data to clarify phylogenetic relationships and examine the role of hybridization in the subsection. We construct haplotype and nucleotype networks from chloroplast and nuclear ITS sequence matrices and compare nuclear and chloroplast phylogenies to identify multiple putative chloroplast capture events. The RAD‐seq maximum likelihood phylogeny and multispecies coalescent species tree robustly resolve relationships between six species‐level clades. We use STRUCTURE and HyDe on the RAD‐seq data to evaluate the influence of hybridization within the subsection. The HyDe results suggest that hybridization has occurred among all species in the subsection at some point in their history. Cytonuclear discordance reveals historic chloroplast capture, and we discuss potential causes of the observed discordance. Our study robustly resolves relationships in Aliciella subsection Subnuda and provides a framework for discussing its speciation despite a history of hybridization and introgression.

In the face of a rapidly changing climate, spring-fed habitats are increasingly vulnerable to numerous threats. Botanical inventories provide valuable information to assess the conservation value of desert springs, and can serve as indicators to document changing conditions, including the proportion of native vs. nonnative taxa, diversity of life forms present that influence structure and function of ecosystems, species persistence and longevity, and the proportion of taxa that are rare and sensitive to land use change. Here we evaluate plant species composition and richness within and between springs, and evaluate botanical diversity with respect to physical parameters including hydrology and geography. We find that desert springs collectively support a large proportion of plant diversity, or nearly 22% of the total vascular plant diversity known within the California desert in only 0.000005% of the total land area. The springs we sampled are highly dissimilar in plant species composition, thus, restoration and management activities likely need to be highly individualized and site specific. Monitoring and inventory programs can increase opportunities for restoration and protection by providing information to assess warning signs of habitat degradation, such as changing species composition and local extirpation of wetland-dependent species.

Poaceae (the grasses) includes rice, maize, wheat, and other crops, and is the most economically important angiosperm family. Poaceae is also one of the largest plant families, consisting of over 11 000 species with a global distribution that contributes to diverse ecosystems. Poaceae species are classified into 12 subfamilies, with generally strong phylogenetic support for their monophyly. However, many relationships within subfamilies, among tribes and/or subtribes, remain uncertain. To better resolve the Poaceae phylogeny, we generated 342 transcriptomic and seven genomic datasets; these were combined with other genomic and transcriptomic datasets to provide sequences for 357 Poaceae species in 231 genera, representing 45 tribes and all 12 subfamilies. Over 1200 low-copy nuclear genes were retrieved from these datasets, with several subsets obtained using additional criteria, and used for coalescent analyses to reconstruct a Poaceae phylogeny. Our results strongly support the monophyly of 11 subfamilies; however, the subfamily Puelioideae was separated into two non-sister clades, one for each of the two previously defined tribes, supporting a hypothesis that places each tribe in a separate subfamily. Molecular clock analyses estimated the crown age of Poaceae to be ∼101 million years old. Ancestral character reconstruction of C3/C4 photosynthesis supports the hypothesis of multiple independent origins of C4 photosynthesis. These origins are further supported by phylogenetic analysis of the ppc gene family that encodes the phosphoenolpyruvate carboxylase, which suggests that members of three paralogous subclades (ppc-aL1a, ppc-aL1b, and ppc-B2) were recruited as functional C4ppc genes. This study provides valuable resources and a robust phylogenetic framework for evolutionary analyses of the grass family.

Astragalus tricarinatus A.Gray (triple-ribbed milkvetch) is a rare perennial herb endemic to southern California and is listed as endangered under the Federal Endangered Species Act. Field surveys conducted between 2014 and 2017 relocated A. tricarinatus at one of three historical occurrences in the southern portion of its range in Riverside County, California. Surveys in the Chuckwalla Mountains and Orocopia Mountains were not successful in relocating historical occurrences; however, new occurrences were documented in the Santa Rosa Mountains. Plants in the Santa Rosa Mountains were growing on carbonate soils, a substrate that had not been previously associated with A. tricarinatus, which typically occurs on metamorphic rock of granitic origin.

In arid landscapes where fresh water is a limiting resource, the expression of groundwater in springs sustains important landscape functions, globally-recognized biodiversity hotspots, and both aquatic endemic and wide-ranging terrestrial species. Desert springs and associated groundwater dependent ecosystems are threatened by unsustainable groundwater pumping, and the Mojave Desert has seen extinctions of species due to the human use and modification of springs. To support changes in policy and management that would address the vulnerabilities of springs to unsustainable groundwater extraction and other threats, a better understanding of current spring condition is needed. Here we present the results of a comprehensive survey of Mojave Desert springs including hydrological and ecological observations, and an eDNA pilot study. Together, these investigations provide information about the present status of Mojave Desert springs, conservation challenges that they face, and needs that must be met to protect them. We also provide an overview of the current state of federal and state policy that could be used to better manage these critical freshwater resources.

Abstract—The genus Hechtia includes 84 species, 79 of them present in Mexico. With 12 species (including those described herein), the Mexican state of Guerrero is the third most diverse in species. As a result of botanical explorations for the project Bromeliaceae of Mexico, we describe here five new species for science, all endemic to Guerrero: Hechtia elegans, H. ensifolia, H. medusae, H. platyphylla, and H. pycnostachya. The proposed species are compared with other morphologically similar taxa (H. caulescens, H. flexilifolia, H. glauca, H. hintoniana, H. laxissima, and H. pretiosa). Morphological descriptions, images, and a distribution map of the described taxa are included, as well as an identification key for all the species of Hechtia currently known from Guerrero.

Plants, and the biological systems around them, are key to the future health of the planet and its inhabitants. The Plant Science Decadal Vision 2020–2030 frames our ability to perform vital and far‐reaching research in plant systems sciences, essential to how we value participants and apply emerging technologies. We outline a comprehensive vision for addressing some of our most pressing global problems through discovery, practical applications, and education. The Decadal Vision was developed by the participants at the Plant Summit 2019, a community event organized by the Plant Science Research Network. The Decadal Vision describes a holistic vision for the next decade of plant science that blends recommendations for research, people, and technology. Going beyond discoveries and applications, we, the plant science community, must implement bold, innovative changes to research cultures and training paradigms in this era of automation, virtualization, and the looming shadow of climate change. Our vision and hopes for the next decade are encapsulated in the phrase reimagining the potential of plants for a healthy and sustainable future. The Decadal Vision recognizes the vital intersection of human and scientific elements and demands an integrated implementation of strategies for research (Goals 1–4), people (Goals 5 and 6), and technology (Goals 7 and 8). This report is intended to help inspire and guide the research community, scientific societies, federal funding agencies, private philanthropies, corporations, educators, entrepreneurs, and early career researchers over the next 10 years. The research encompass experimental and computational approaches to understanding and predicting ecosystem behavior; novel production systems for food, feed, and fiber with greater crop diversity, efficiency, productivity, and resilience that improve ecosystem health; approaches to realize the potential for advances in nutrition, discovery and engineering of plant‐based medicines, and "green infrastructure." Launching the Transparent Plant will use experimental and computational approaches to break down the phytobiome into a "parts store" that supports tinkering and supports query, prediction, and rapid‐response problem solving. Equity, diversity, and inclusion are indispensable cornerstones of realizing our vision. We make recommendations around funding and systems that support customized professional development. Plant systems are frequently taken for granted therefore we make recommendations to improve plant awareness and community science programs to increase understanding of scientific research. We prioritize emerging technologies, focusing on non‐invasive imaging, sensors, and plug‐and‐play portable lab technologies, coupled with enabling computational advances. Plant systems science will benefit from data management and future advances in automation, machine learning, natural language processing, and artificial intelligence‐assisted data integration, pattern identification, and decision making. Implementation of this vision will transform plant systems science and ripple outwards through society and across the globe. Beyond deepening our biological understanding, we envision entirely new applications. We further anticipate a wave of diversification of plant systems practitioners while stimulating community engagement, underpinning increasing entrepreneurship. This surge of engagement and knowledge will help satisfy and stoke people's natural curiosity about the future, and their desire to prepare for it, as they seek fuller information about food, health, climate and ecological systems.

Abstract Increases in the incidence and severity of drought threaten the viability of rare plants in arid regions. The endangered Nichol's Turk's head cactus (Echinocactus horizonthalonius Lemaire var. nicholii L. Benson) occurs only in four small, isolated populations in the Sonoran Desert of North America. Since 1995 we have monitored a population in southeastern Arizona (USA). Here we report 23 years of observations on abundance, growth, mortality, flowering and recruitment. Abundance of plants decreased from 132 in 1996 to 40 in 2017, with 100 individuals recruited and 203 dying during the study. Individual plants grew slowly, increasing annually by an average of 0.22 cm (95% confidence interval, 0.18–0.26 cm) in diameter and 0.27 cm (0.20–0.33 cm) in height. Growth was slowest when drought was most severe and slowed as plants reached maximum size. Annual mortality increased markedly across the study period and did not vary with plant size. Annual probability of flowering increased as plants increased in diameter but not in height, and varied with precipitation and drought but not with mean annual temperature. Recruitment was higher when average temperature was higher and the number of recruits per capita increased across the study period. The annual rate of change in abundance averaged −6%, but shifted markedly from −1% during 1995–2008 to −11% during 2008–2017. Our results indicate that the population's decline was not a consequence of failed recruitment but of increased mortality, which we discuss in the context of climate and herbivory.

SummaryDNA sequence data, macro-morphological evidence and pollen analysis are used to clarify the phylogenetic placement of two African species of Acanthaceae: Schaueria populifolia C.B.Clarke and Rhinacanthus ndorensis Schweinf. The combined data demonstrate that these species are only distantly related to the genera in which they are currently placed and provide strong support for recognition of new genera to accommodate them. Two new genera are therefore proposed and a taxonomic account is provided for each of these. The first, Champluviera I.Darbysh., T.F.Daniel & C.A.Kiel, is based primarily on S. populifolia but Chlamydocardia nuda C.B.Clarke (= Justicia tigrina Heine) is also included within this new genus based on shared morphological traits, at least one of which is synapomorphic and restricted to these species. Based on molecular evidence, Champluviera is placed in a well-supported clade of several genera that are together sister to the core Isoglossinae lineage of tribe Justicieae. The genus may be recognised morphologically by the combination of a dense spiciform terminal thyrse with the bracts, bracteoles and calyx lobes all slender and closely resembling one another; a bilabiate corolla lacking a rugula and with intricate speckling or striping on the lips; and, in particular, the putatively synapomorphic trait of anther thecae with broad, flattened, basal appendages that have an irregularly toothed fringe. The second new genus, Kenyacanthus I.Darbysh. & C.A.Kiel, is based on R. ndorensis and is so far thought to be monospecific. It is placed between core Diclipterinae and Monechma Group II within the expanded subtribe Diclipterinae in tribe Justicieae. Kenyacanthus can be recognised morphologically by having the combination of a trailing or procumbent habit; fasciculate inflorescences; bracts, bracteoles and calyces with hyaline margins; a bilabiate corolla with a slender cylindrical tube longer than the limb and with a shallow rugula; stenotribic flowers, with the stamens held against the lower lip; and anthers with only slightly offset thecae that lack appendages.