A re-examination of the circumscription of Saxifraga mengtzeana (Saxifragaceae).

In the Flora of China account of Saxifraga mengtzeana Engl. & Irmsch., eight synonyms were attributed to it and one variant, recognized as Saxifraga epiphylla Gornall & Ohba, was split from it. This study reevaluates the taxonomic status of some of the synonyms and of the segregated species in light of new evidence presented here. Morphological and molecular evidence demonstrate that collections from northwestern Yunnan and Sichuan are genetically differentiated from those in southeastern Yunnan and neighboring Guangxi. Observations in the field and in cultivation show that the peltate petiole attachment diagnostic of S. mengtzeana var. peltifolia Engl. & Irmsch. is developmentally labile. Similar observations combined with molecular data show that viviparous phenotypes, formerly treated as S. epiphylla, although largely under genetic control, occur sporadically throughout the ranges of both northern and southern taxa. Collections from northwestern Yunnan and Sichuan are best recognized as Saxifraga geifolia Balf.f., whereas those from southeastern Yunnan and neighboring Guangxi are S. mengtzeana. Peltate-leaved variants of the latter are given no status and are relegated to complete synonymy. Viviparous phenotypes of S. mengtzeana and S. geifolia are recognized at the rank of forma.

Chloroplast phylogenomics and the taxonomy of Saxifraga section Ciliatae (Saxifragaceae).

Comprising ca. 200 species, Saxifraga sect. Ciliatae is the most species-rich section of Saxifraga s.str., whose center of diversity is in the Tibeto-Himalayan region. The infra-sectional classification of sect. Ciliatae is still in debate due to the high level of species richness, as well as remarkable variations of habitat, morphology, physiology and life cycles. Subdivisions of this section proposed in various taxonomic systems have not been adequately tested in previous phylogenetic studies, partly due to low taxonomic sampling density, but also to the use of few DNA markers. In order to achieve a more robust infra-sectional classification of sect. Ciliatae, complete chloroplast genomes of 94 taxa from this section were analyzed, of which 93 were newly sequenced, assembled and annotated. The length of the 94 plastomes of sect. Ciliatae taxa range from 143,479 to 159,938 bp, encoding 75 to 79 unique protein-coding genes (PCGs). Analyses of the 94 plastomes revealed high conservation in structural organization, gene arrangement, and gene content. Gene loss and changes of IR boundaries were detected but in extremely low frequency. The molecular phylogenetic tree from concatenated PCGs and complete chloroplast genome sequences exhibited high resolution and support values and confirms that sect. Ciliatae is monophyletic. Three well-supported clades were revealed within the section that agree relatively well with the subsectional taxonomy of Gornall (1987), but some minor modifications should be made. Firstly, the monotypic subsection Cinerascentes should be abandoned and its constituent species, S. cinerascens, assigned to subsect. Gemmiparae. Secondly, subsections Rosulares and Serpyllifoliae should be merged and become subsect. Rosulares. Section Ciliatae thus comprises: subsect. Hirculoideae Engl. & Irmsch.; subsect. Rosulares Gornall; subsect. Gemmiparae Engl. & Irmsch.; subsect. Flagellares (C. B. Clarke) Engl. & Irmsch. and subsect. Hemisphaericae (Engl. & Irmsch.) Gornall.

A taxonomic, genetic and ecological data resource for the vascular plants of Britain and Ireland.

The vascular flora of Britain and Ireland is among the most extensively studied in the world, but the current knowledge base is fragmentary, with taxonomic, ecological and genetic information scattered across different resources. Here we present the first comprehensive data repository of native and alien species optimized for fast and easy online access for ecological, evolutionary and conservation analyses. The inventory is based on the most recent reference flora of Britain and Ireland, with taxon names linked to unique Kew taxon identifiers and DNA barcode data. Our data resource for 3,227 species and 26 traits includes existing and unpublished genome sizes, chromosome numbers and life strategy and life-form assessments, along with existing data on functional traits, species distribution metrics, hybrid propensity, associated biomes, realized niche description, native status and geographic origin of alien species. This resource will facilitate both fundamental and applied research and enhance our understanding of the flora's composition and temporal changes to inform conservation efforts in the face of ongoing climate change and biodiversity loss.

Using demand mapping to assess the benefits of urban green and blue space in cities from four continents.

The benefits of urban green and blue infrastructure (UGI) are widely discussed, but rarely take into account local conditions or contexts. Although assessments increasingly consider the demand for the ecosystem services that UGI provides, they tend to only map the spatial pattern of pressures such as heat, or air pollution, and lack a wider understanding of where the beneficiaries are located and who will benefit most. We assess UGI in five cities from four continents with contrasting climate, socio-political context, and size. For three example services (air pollution removal, heat mitigation, accessible greenspace), we run an assessment that takes into account spatial patterns in the socio-economic demand for ecosystem services and develops metrics that reflect local context, drawing on the principles of vulnerability assessment. Despite similar overall levels of UGI (from 35 to 50% of urban footprint), the amount of service provided differs substantially between cities. Aggregate cooling ranged from 0.44 °C (Leicester) to 0.98 °C (Medellin), while pollution removal ranged from 488 kg PM2.5/yr (Zomba) to 48,400 kg PM2.5/yr (Dhaka). Percentage population with access to nearby greenspace ranged from 82% (Dhaka) to 100% (Zomba). The spatial patterns of pressure, of ecosystem service, and of maximum benefit within a city do not necessarily match, and this has implications for planning optimum locations for UGI in cities.

Population Genetic Differentiation and Taxonomy of Three Closely Related Species of Saxifraga (Saxifragaceae) from Southern Tibet and the Hengduan Mountains.

The effects of rapid, recent uplift of the Hengduan Mountains on evolution and diversification of young floristic lineages still remain unclear. Here, we investigate diversification of three closely related Saxifraga species with a distribution restricted to the Hengduan Mountains (HM) and southern Tibet, and comment on their taxonomy based on molecular evidence. Three chloroplast DNA fragments (rbcL, trnL-F, trnS-G) and the nuclear ribosomal DNA internal transcribed spacer (ITS) were employed to study genetic structure across 104 individuals from 12 populations of Saxifraga umbellulata, S. pasumensis, and S. banmaensis. Chloroplast DNA (cpDNA) phylogenies revealed two well supported clades, corresponding to S. umbellulata and S. pasumensis plus S. banmaensis. Topology of the ITS phylogeny was largely congruent with that generated from cpDNA haplotypes, but with minor conflicts which might be caused by incomplete lineage sorting. Analyses of molecular variance of both cpDNA and ITS datasets revealed that most variation was held between S. pasumensis s.l. (with S. banmaensis) and S. umbellulata (92.31% for cpDNA; 69.78% for ITS), suggesting a high degree of genetic divergence between them. Molecular clock analysis based on ITS dataset suggested that the divergence between S. pasumensis s.l. and S. umbellulata can be dated to 8.50 Ma, probably a result of vicariant allopatric diversification associated with the uplift events of the HM. Vicariance associated with HM uplifts may also have been responsible for infraspecific differentiation in S. pasumensis. In contrast, infraspecific differentiation in S. umbellulata was most likely triggered by Quaternary glaciations. The much lower levels of gene diversity within populations of S. pasumensis compared with S. umbellulata could have resulted from both range contractions and human collection on account of its putative medicinal properties. Combining evidence from morphology, geographical distributions and molecular phylogenetic data, we recommend that S. banmaensis should be treated as a synonym of S. pasumensis which in turn, and based on the same sources of evidence, should be treated as a separate species rather than as a variety of S. umbellulata.

Complete chloroplast genomes from apomictic Taraxacum (Asteraceae): Identity and variation between three microspecies.

Chloroplast DNA sequences show substantial variation between higher plant species, and less variation within species, so are typically excellent markers to investigate evolutionary, population and genetic relationships and phylogenies. We sequenced the plastomes of Taraxacum obtusifrons Markl. (O978); T. stridulum Trávnicek ined. (S3); and T. amplum Markl. (A978), three apomictic triploid (2n = 3x = 24) dandelions from the T. officinale agg. We aimed to characterize the variation in plastomes, define relationships and correlations with the apomictic microspecies status, and refine placement of the microspecies in the evolutionary or phylogenetic context of the Asteraceae. The chloroplast genomes of accessions O978 and S3 were identical and 151,322 bp long (where the nuclear genes are known to show variation), while A978 was 151,349 bp long. All three genomes contained 135 unique genes, with an additional copy of the trnF-GGA gene in the LSC region and 20 duplicated genes in the IR region, along with short repeats, the typical major Inverted Repeats (IR1 and IR2, 24,431bp long), and Large and Small Single Copy regions (LSC 83,889bp and SSC 18,571bp in O978). Between the two Taraxacum plastomes types, we identified 28 SNPs. The distribution of polymorphisms suggests some parts of the Taraxacum plastome are evolving at a slower rate. There was a hemi-nested inversion in the LSC region that is common to Asteraceae, and an SSC inversion from ndhF to rps15 found only in some Asteraceae lineages. A comparative repeat analysis showed variation between Taraxacum and the phylogenetically close genus Lactuca, with many more direct repeats of 40bp or more in Lactuca (1% larger plastome than Taraxacum). When individual genes and non-coding regions were for Asteraceae phylogeny reconstruction, not all showed the same evolutionary scenario suggesting care is needed for interpretation of relationships if a limited number of markers are used. Studying genotypic diversity in plastomes is important to characterize the nature of evolutionary processes in nuclear and cytoplasmic genomes with the different selection pressures, population structures and breeding systems.