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  1. Abstract

    The northern temperate genusDracocephalumconsists of approximately 70 species mainly distributed in the steppe‐desert biomes of Central and West Asia and the alpine region of the Qinghai‐Tibetan Plateau (QTP). Previous work has shown thatDracocephalumis not monophyletic and might includeHyssopusandLallemantia. This study attempts to clarify the phylogenetic relationships, diversification patterns, and the biogeographical history of the three genera (defined asDracocephalums.l.). Based on a sampling of 66 taxa comprising more than 80% from extant species ofDracocephalums.l., morphological, phylogenetic (maximum parsimony, likelihood, and Bayesian inference based on nuclear ITS and ETS, plastidrpl32‐trnL,trnL‐trnF,ycf1, andycf1‐rps15, and two low‐copy nuclear markersAT3G09060andAT1G09680), molecular dating, diversification, and ancestral range estimation analyses were carried out. Our results demonstrate that bothHyssopusandLallemantiaare embedded withinDracocephalumand nine well‐supported clades can be recognized withinDracocephalums.l. Analyses of divergence times suggest that the genus experienced an early rapid radiation during the middle to late Miocene with major lineages diversifying within a relatively narrow timescale. Ancestral area reconstruction analyses indicate thatDracocephalums.l. originated in Central and West Asia and southern Siberia, and dispersed from Central and West Asia into the QTP and adjacent areas twice independently during the Pliocene. The aridification of the Asian interior possibly promoted the rapid radiation ofDracocephalumwithin this region, and the uplift of the QTP appears to have triggered the dispersal and recent rapid diversification of the genus in the QTP and adjacent regions. Combining molecular phylogenetic and morphological evidence, a revised infrageneric classification ofDracocephalums.l. is proposed, which recognizes nine sections within the genus.

     
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  2. The genus Salvia is comprised of about 1000 species and has diversity hotspots in the Americas, East Asia, southwest Asia and the Mediterranean region. Central Asia also possesses considerable Salvia species diversity but is understudied relative to the aforementioned diversity hotspots. To help remedy this deficiency, we present a synopsis of Central Asian Salvia species based on extensive fieldwork, herbarium consultation, and literature surveys focusing on Uzbekistan, Kyrgyzstan, Tajikistan, Kazakhstan, and Turkmenistan (i.e., Central Asia). According to our final taxonomic revision, there are 41 species of native Salvia in the flora of Central Asia, 24 of which are endemic. Salvia ariana from Tajikistan and S. spinosa from Kazakhstan are documented from the respective countries for the first time, and the presence of S. tianschanica from Tajikistan and S. verticillata from Kazakhstan has been confirmed. In addition, the neotypification of S. deserta and three lectotypifications (Perovskia abrotanoides, S. bucharica and S. trautvetterii) are provided. Furthermore, we synonymized six species of Salvia that were previously reported from Central Asia, including S. intercedens, S. kopetdaghensis, S. linczevskii, S. lipskyi, S. semilanata and S. stepposa. Finally, a new species identification key for Central Asian Salvia is presented based on the new nomenclature changes and our taxonomic revision. 
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  3. Abstract Winter annuals comprise a large fraction of warm-desert plant species, but the drivers of their diversity are little understood. One factor that has generally been overlooked is the lack of obvious means of long-distance seed dispersal in many desert-annual lineages, which could lead to genetic differentiation at small spatial scales and, ultimately, to speciation and narrow endemism. If our gene-flow hypothesis is correct, individual winter-annual species should have populations with genetic spatial structures implying short distances of gene flow. To test this idea, we sampled six populations of Eschscholzia parishii (Papaveraceae) in three pairs of watersheds within a 28-km radius in southern California. We quantified genetic diversity and structure and inferred the distance of gene flow in these populations using single nucleotide polymorphisms derived from genotyping-by-sequencing. Estimated distances of gene flow were quite small (σ = 10.4–14.9 m), with strong genetic structure observed within and between populations. Kinship declined steeply with ln distance (r2 = 0.85). Petal size and shape differed significantly between the northernmost and southernmost populations. These findings support the hypothesis that the high diversity of warm-desert winter annuals might result, in part, from genetic differentiation within species at small spatial scales driven by poor seed dispersal. 
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  4. Monardella (Lamiaceae) is a taxonomically complex western North American genus ranging from the Pacific coast to the western slopes of the Rocky Mountains and from southern British Columbia in Canada to the Cape region of Baja California Sur in Mexico. We applied a combination of gross vegetative morphology, trichome morphology and abundance/distribution, and molecular data to clarify taxonomic discontinuities, specifically regarding the monophyly of plants formerly treated within Monardella odoratissima. The data suggest a clear distinction between the non-monophyletic M. odoratissima species complex and the M. ovata species complex, thus resolving taxonomic ambiguities within and between them. We formally recognize plants from southern Oregon, northern California, and western Nevada previously misapplied to M. odoratissima as belonging to the M. ovata species complex. We introduce the following taxonomic and nomenclatural revisions: describe M. ovata Greene subsp. lenmaniae as a novel subspecies; present M. ovata subsp. pallida at a new position and rank; recognize M. modocensis, M. ovata, and M. rubella as accepted taxa; designate lectotypes for M. modocensis and M. rubella; and designate M. californica and M. tortifolia as new synonyms under M. ovata. 
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  5. null (Ed.)
    Abstract Background A robust molecular phylogeny is fundamental for developing a stable classification and providing a solid framework to understand patterns of diversification, historical biogeography, and character evolution. As the sixth largest angiosperm family, Lamiaceae, or the mint family, consitutes a major source of aromatic oil, wood, ornamentals, and culinary and medicinal herbs, making it an exceptionally important group ecologically, ethnobotanically, and floristically. The lack of a reliable phylogenetic framework for this family has thus far hindered broad-scale biogeographic studies and our comprehension of diversification. Although significant progress has been made towards clarifying Lamiaceae relationships during the past three decades, the resolution of a phylogenetic backbone at the tribal level has remained one of the greatest challenges due to limited availability of genetic data. Results We performed phylogenetic analyses of Lamiaceae to infer relationships at the tribal level using 79 protein-coding plastid genes from 175 accessions representing 170 taxa, 79 genera, and all 12 subfamilies. Both maximum likelihood and Bayesian analyses yielded a more robust phylogenetic hypothesis relative to previous studies and supported the monophyly of all 12 subfamilies, and a classification for 22 tribes, three of which are newly recognized in this study. As a consequence, we propose an updated phylogenetically informed tribal classification for Lamiaceae that is supplemented with a detailed summary of taxonomic history, generic and species diversity, morphology, synapomorphies, and distribution for each subfamily and tribe. Conclusions Increased taxon sampling conjoined with phylogenetic analyses based on plastome sequences has provided robust support at both deep and shallow nodes and offers new insights into the phylogenetic relationships among tribes and subfamilies of Lamiaceae. This robust phylogenetic backbone of Lamiaceae will serve as a framework for future studies on mint classification, biogeography, character evolution, and diversification. Graphical abstract 
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  6. null (Ed.)
    Paralamium (Lamiaceae) is a monotypic genus within the subfamily Lamioideae and has a sporadic distribution in subtropical mountains of southeast Asia. Although recent studies have greatly improved our understanding of generic relationships within Lamioideae, the second most species-rich subfamily of Lamiaceae, the systematic position of Paralamium within the subfamily remains unclear. In this study, we investigate the phylogenetic placement of the genus using three datasets: (1) a 69,276 bp plastome alignment of Lamiaceae; (2) a five chloroplast DNA region dataset of tribe Pogostemoneae, and (3) a nuclear ribosomal internal transcribed spacer region dataset of Pogostemoneae. These analyses demonstrate that Paralamium is a member of Pogostemoneae and sister to the monotypic genus Craniotome . In addition, generic-level phylogenetic relationships within Pogostemoneae are also discussed, and a dichotomous key for genera within Pogostemoneae is provided. 
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