The Lactucinae or Lactuca alliance include approximately 200 species distributed across the Northern Hemisphere and Africa. They were not recognised as a separate lineage until the late 20th century and their circumscription is still not fully settled. The generic classification of no other group of the Cichorieae has faced as many controversies as the Lactuca alliance and competing taxonomies coexist. This paper provides the first molecular phylogeny of the subtribe on a global scale as a major step towards its revised systematics. The sampling includes almost 60% of the species-level diversity and spans all species groups. Two datasets were created, one including the nrDNA ITS region, the other five concatenated non-coding plastid DNA loci. Maximum parsimony, maximum likelihood and Bayesian inference were used to produce a robust phylogenetic backbone. The diversification and expansion of the Lactucinae in a geohistorical context was reconstructed by estimating the age of their lineages using relaxed molecular clock dating and by inferring the ancestral areas using Bayesian binary analysis. The redelimited monophyletic Lactucinae are composed of seven lineages that also include Prenanthes, which is confirmed to have a single species, P. purpurea. The positions of two further lineages shift between Lactucinae and Crepidinae in the nuclear and plastid DNA phylogenies. Incongruence between the phylogenies suggests events of ancient reticulation or incomplete lineage sorting in the formation of these latter two lineages and in two of the seven other Lactucinae lineages. The phylogenetic results show a dilemma for Lactucinae systematics: most generic concepts proposed to date are highly artificial but the resolved phylogenetic lineages do not constitute practicable taxonomic entities with our current knowledge. Diversification of the subtribe is inferred to have taken place since the Middle Miocene. Biogeographic analysis proposes that the clade originated in the mountains of the landmass mediating between the European and Asian continents and delimited in the south by the Tethys Sea and in the north by the Paratethys Sea. Several independent migrations have occurred into various parts of Asia, Europe, tropical Africa and North America.
Classification of the tribe Cardueae in natural subtribes has always been a challenge due to the lack of support of some critical branches in previous phylogenies based on traditional Sanger markers. With the aim to propose a new subtribal delimitation, we applied a Hyb-Seq approach to a set of 76 Cardueae species representing all the subtribes and informal groups defined in the tribe, targeting 1061 nuclear conserved orthology loci (COS) designed for Compositae and obtaining chloroplast coding regions as byproduct of off-target reads. For the extraction of target nuclear data, we used two strategies, PHYLUCE and HybPiper, and 776 and 1055 COS loci were recovered with each of them, respectively. Additionally, 87 chloroplast genes were assembled and annotated. With the three datasets, phylogenetic relationships within the tribe were reconstructed under approaches of concatenation (using supermatrices as input for maximum likelihood analysis with RAxML) and coalescence (species tree estimated with ASTRAL based on the individual gene trees of each COS locus). The phylogenetic analyses of the nuclear datasets fully resolved virtually all nodes with very high support. Although nuclear and plastid tree topologies are highly congruent, they still present some incongruences, which are shortly discussed. On the basis of the phylogenies obtained, we propose a new taxonomic scheme of 12 monophyletic and morphologically consistent subtribes: Carlininae, Cardopatiinae, Echinopsinae, Dipterocominae (new), Xerantheminae (new), Berardiinae (new), Staehelininae (new), Onopordinae (new), Carduinae (redelimited), Arctiinae (new), Saussureinae (new), and Centaureinae. Another main key result of the study was the high resolution recovered at the backbone of the Cardueae tree, which led to obtain better inter-subtribal relationships. Using as tree base the nuclear HybPiper phylogeny, we updated the temporal framework for the origin and diversification of the tribe and subtribes. Overall, the power of Hyb-Seq is demonstrated to solve relationships traditionally suggested by morphology but never recovered with support using Sanger sequencing of a few DNA markers.
Target enrichment is a cost-effective sequencing technique that holds promise for elucidating evolutionary relationships in fast-evolving lineages. However, potential biases and impact of bioinformatic sequence treatments in phylogenetic inference have not been thoroughly explored yet. Here, we investigate this issue with an ultimate goal to shed light into a highly diversified group of Compositae (Asteraceae) constituted by four main genera: Arctium, Cousinia, Saussurea, and Jurinea. Specifically, we compared sequence data extraction methods implemented in two easy-to-use workflows, PHYLUCE and HybPiper, and assessed the impact of two filtering practices intended to reduce phylogenetic noise. In addition, we compared two phylogenetic inference methods: (1) the concatenation approach, in which all loci were concatenated in a supermatrix; and (2) the coalescence approach, in which gene trees were produced independently and then used to construct a species tree under coalescence assumptions. Here we confirm the usefulness of the set of 1061 COS targets (a nuclear conserved orthology loci set developed for the Compositae) across a variety of taxonomic levels. Intergeneric relationships were completely resolved: there are two sister groups, Arctium-Cousinia and Saussurea-Jurinea, which are in agreement with a morphological hypothesis. Intrageneric relationships among species of Arctium, Cousinia, and Saussurea are also well defined. Conversely, conflicting species relationships remain for Jurinea. Methodological choices significantly affected phylogenies in terms of topology, branch length, and support. Across all analyses, the phylogeny obtained using HybPiper and the strictest scheme of removing fast-evolving sites was estimated as the optimal. Regarding methodological choices, we conclude that: (1) trees obtained under the coalescence approach are topologically more congruent between them than those inferred using the concatenation approach; (2) refining treatments only improved support values under the concatenation approach; and (3) branch support values are maximized when fast-evolving sites are removed in the concatenation approach, and when a higher number of loci is analyzed in the coalescence approach.
A new project, 'Flora of Uzbekistan', is announced to start with publication in 2017. It aims at publishing a multi-volume taxonomic treatment of vascular plants of Uzbekistan, with complete synonymy, nomenclature, distribution data, descriptions and identification keys. The taxonomic treatment is supported by an extensive database of distribution records, used to generate distribution maps. The background information for the Flora is provided, and the structure and the format of the work are outlined.
The NERC and CEH trademarks and logos ('the Trademarks') are registered trademarks of NERC in the UK and other countries, and may not be used without the prior written consent of the Trademark owner. Please cite as: Heikinheimo, H., Eronen, J.T., Sennikov, A., Preston, C.D., Uotila, P., Mannila, H., Fortelius, M. 2012. Converge in distribution patterns of Europe's plants and mammals is due to environmental forcing. Journal of Biogeography 39, 1633-1644
We present a comprehensive list of non-native vascular plant species known from the Arctic, explore their characteristics, analyze the extent of naturalization and invasion among investigated regions, and examine pathways of non-native plant introductions. The presence of 341 non-native species in the Arctic was confirmed, of which 188 are naturalized in at least one of 23 regions, while 11 taxa are invasive in three regions. In several Arctic regions there are no naturalized non-native species recorded, whereas in the majority of Arctic regions the number of naturalized species is low. Biogeographic analyses of the non-native vascular plant flora identified three main clusters within the Arctic: American, Asiatic and European. Among all pathways, seed contamination and transport by vehicles have contributed the most to non-native plant introduction to the Arctic.
Jurinea (Asteraceae: Cardueae) is a large Eurasian genus of about 180 species with centres of diversity in Central and Southwest Asia and the eastern Mediterranean. The genus includes many species with adaptations to xero-and chasmophytic habitats and comprises numerous endemics, especially in the Caucasus. Generic delimitations between Jurinea and closely related genera have been difficult to assess, as have the phylogenetic relationships with the genera Himalaiella, Jurinella and Lipschitziella, each of which has been suggested as congeneric with Jurinea. A molecular phylogenetic investigation at both the specific and the generic level to establish the generic delimitation of Jurinea and to evaluate the intergeneric relationships of the genus with other members of the Cardueae was hitherto lacking. In this study, we reconstruct the phylogenetic relationships between Jurinea and several closely related genera based on a representative taxon sampling using DNA sequence data of nuclear (ITS, ETS) and plastid DNA regions (trnK/matK, trnL-F). We also evaluate the infrageneric classification of Jurinea. Our results indicate that Jurinea is polyphyletic in its current circumscription, as the species J. gedrosiaca and J. cartilaginea are placed within the subtribe Centaureineae of the Cardueae. The rest of Jurinea is monophyletic and split into two major clades corresponding to the western and eastern range of the distribution area of the genus. The sister clade of Jurinea is composed of Himalaiella and Lipschitziella. Jurinella, which was segregated from Jurinea based on achene morphology, is congeneric with Jurinea. Like in other speciose Eurasian genera, the currently recognised sections do not reflect natural groups, whereas most clades found through molecular phylogenetic inference correlate with geographic patterns. A clade that exclusively comprises Caucasian endemics, including the narrow endemics of J. sect. Neobellae, was found. This clade represents an interesting study group for possible radiation events of Jurinea in the Caucasus.
Smith & al. (2010) have suggested that the apportionment of institutional votes for the Nomenclature Section of the International Botanical Congress based upon taxonomic activity represents a “colonial legacy” that disadvantages developing nations, and that institutional votes should instead be distributed based at least in part upon a country's human population and the size of its flora. While we agree that increasing participation by developing‐country taxonomists is an important goal, we believe that Smith & al. fail to support their claim that the current practice of plant nomenclature is harmful to developing nations. No evidence has been offered of regional biases regarding proposals to change the wording of the Code, which represent the vast majority of the votes taken at any Nomenclature Section, nor has the current process of apportionment of institutional votes been shown to be biased. The reform measures proposed by Smith & al. would, as we show, introduce explicit discrimination based on nationality into the International code of botanical nomenclature, undermining the international cooperation among taxonomists that is necessary for the smooth functioning of a universally accepted system of nomenclature. Rather than making hasty and perhaps harmful changes to the current means of voting, we suggest that the international taxonomic community should consider carefully what measures will best facilitate participation without creating new sources of injustice.
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