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Euphorbia fauriei, a perennial plant endemic to South Korea, exhibits both morphological characteristics and intricate genetic identities akin to E. pekinensis. This study aimed to provide clarity on the taxonomic status of E. faurirei and E. pekinensis through a comprehensive chloroplast genome analysis. Additionally, we sequenced the Acalypha australis chloroplast genome as an outgroup for the construction of a phylogenetic tree with other Euphorbia species. The three chloroplast genomes, ranging from 162,834 bp to 168,832 bp, displayed typical quadripartite structures. The Euphorbia genomes contained 111 unique genes, whereas the A. australis genome contained two additional protein-coding genes (PCGs), rpl32 and rps16. Comparative analysis unveiled the loss of rpl32 and rps16 as synapomorphic characteristics in Euphorbia, whereas the loss of infA occurred across Euphorbiaceae. High collinearity and sequence similarity were observed among Euphorbia species, accompanied by significant inversion regions in the E. pekinensis chloroplast genomes from China and Japan, indicating regional genetic variability. Nucleotide substitution analysis revealed that the ndh group exhibited the highest K A /K S values (0.224), whereas the atp, psa, psb and rps groups had the lowest. Phylogenomic analysis utilizing whole genomes, PCGs, and intron and intergenic regions consistently demonstrated that E. pekinensis from South Korea clusters closely with E. fauriei. These findings challenge the current taxonomic distinction between E. pekinensis and E. fauriei in Korea, suggesting that while they exhibit distinct characteristics, E. fauriei should be considered a closely related subspecies rather than the same species as E. pekinensis. This study emphasizes the need for population studies to clarify the taxonomic relationships between E. pekinensis and E. fauriei., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The genus Euphorbia (Euphorbiaceae) has near-cosmopolitan distribution and serves as a significant resource for both ornamental and medicinal purposes. Despite its economic importance, Euphorbia's taxonomy has long been challenged by the intricate nature of morphological traits exhibiting high levels of convergence. While molecular markers are essential for phylogenetic studies, their availability for Euphorbia has been limited. To address this gap, we conducted comparative analyses focusing on the chloroplast (CP) genomes of nine Euphorbia species, incorporating three newly sequenced and annotated accessions. In addition, phylogenetic informativeness and nucleotide diversity were computed to identify candidate markers for phylogenetic analyses among closely related taxa in the genus. Our investigation revealed relatively conserved sizes and structures of CP genomes across the studied species, with notable interspecific variations observed primarily in non-coding regions and IR/SC borders. By leveraging phylogenetic informativeness and nucleotide diversity, we identified rpoB gene as the optimal candidate for species delimitation and shallow-level phylogenetic inference within the genus. Through this comprehensive analysis of CP genomes across multiple taxa, our study sheds light on the evolutionary dynamics and taxonomic intricacies of Euphorbia, offering valuable insights into its CP genome evolution and taxonomy., (© 2024. The Author(s).)

Background and Aims: Biogeographical relationships between the Canary Islands and north-west Africa are often explained by oceanic dispersal and geographical proximity. Sister-group relationships between Canarian and eastern African/Arabian taxa, the 'Rand Flora' pattern, are rare among plants and have been attributed to the extinction of north-western African populations. Euphorbia balsamifera is the only representative species of this pattern that is distributed in the Canary Islands and north-west Africa; it is also one of few species present in all seven islands. Previous studies placed African populations of E. balsamifera as sister to the Canarian populations, but this relationship was based on herbarium samples with highly degraded DNA. Here, we test the extinction hypothesis by sampling new continental populations; we also expand the Canarian sampling to examine the dynamics of island colonization and diversification., Methods: Using target enrichment with genome skimming, we reconstructed phylogenetic relationships within E. balsamifera and between this species and its disjunct relatives. A single nucleotide polymorphism dataset obtained from the target sequences was used to infer population genetic diversity patterns. We used convolutional neural networks to discriminate among alternative Canary Islands colonization scenarios., Key Results: The results confirmed the Rand Flora sister-group relationship between western E. balsamifera and Euphorbia adenensis in the Eritreo-Arabian region and recovered an eastern-western geographical structure among E. balsamifera Canarian populations. Convolutional neural networks supported a scenario of east-to-west island colonization, followed by population extinctions in Lanzarote and Fuerteventura and recolonization from Tenerife and Gran Canaria; a signal of admixture between the eastern island and north-west African populations was recovered., Conclusions: Our findings support the Surfing Syngameon Hypothesis for the colonization of the Canary Islands by E. balsamifera, but also a recent back-colonization to the continent. Populations of E. balsamifera from northwest Africa are not the remnants of an ancestral continental stock, but originated from migration events from Lanzarote and Fuerteventura. This is further evidence that oceanic archipelagos are not a sink for biodiversity, but may be a source of new genetic variability., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Annals of Botany Company.)

Next generation sequencing has revolutionised biology. Restriction-associated DNA sequencing (RADseq) has primarily been used to study infraspecific relationships but has also been applied in multi-species phylogenomic analyses. In this study, we used a combination of phylogenomic (with RADseq data) and phylogenetic (with sequences of the nuclear internal transcribed spacer, ITS) methods to explore relationships within the taxonomically intricate Euphorbia seguieriana s. l., one of the most widespread Euphorbia taxa inhabiting zonal and extrazonal steppes from Iberia to Central Asia. In the inferred phylogenies the southeastern Balkan and Anatolian populations were clearly separated, supporting the distinction of E. niciciana from E. seguieriana at the species level. Within E. seguieriana, the populations from the Caucasus, Iran, and easternmost Anatolia were sister to all other populations based on RADseq, making necessary the description of a new, morphologically divergent subspecies, E. seguieriana subsp. armeniaca. Conversely, additional studies are needed to understand the status of E. seguieriana subsp. hohenackeri, which is sympatric with E. seguieriana subsp. armeniaca. Niche analyses indicated that differences in the climatic niche between E. niciciana and E. seguieriana are relatively small compared with the climatic differences between the regions over which they are distributed. Contrary to previous believes, E. niciciana and E. seguieriana are allopatric and have likely diverged during the Pleistocene in two different glacial refugia as suggested by distribution modelling. Euphorbia niciciana nowadays has a submediterranean distribution, occupying habitats that are slightly warmer, moister, and less seasonal in temperature but more seasonal in precipitation than E. seguieriana, a characteristic species of continental steppes. Using flow cytometry, we demonstrate that the relative genome sizes of E. niciciana and E. seguieriana differ significantly. Additionally, multivariate morphometric analyses of 56 morphological characters indicated clear morphological divergence of the two species. Importantly, we also provide a revised taxonomic treatment including formal nomenclatural changes, an identification key and species descriptions. Our study demonstrates that an integrative approach, combining modern phylogenomic methods with traditional phylogenetic, cytogenetic, environmental and morphological analyses can result in satisfactorily resolved relationships in intricate groups of closely related species. Finally, phylogenetic inference using ITS sequences is still a useful tool for resolving relationships among the taxa at the species level, but the phylogenomic approach based on RADseq data certainly provides better resolution both among and within species., (Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.)

Patterns of adaptation in response to environmental variation are central to our understanding of biodiversity, but predictions of how and when broad-scale environmental conditions such as climate affect organismal form and function remain incomplete. Succulent plants have evolved in response to arid conditions repeatedly, with various plant organs such as leaves, stems, and roots physically modified to increase water storage. Here, we investigate the role played by climate conditions in shaping the evolution of succulent forms in a plant clade endemic to Madagascar and the surrounding islands, part of the hyper-diverse genus Euphorbia (Euphorbiaceae). We used multivariate ordination of 19 climate variables to identify links between particular climate variables and three major forms of succulence-succulent leaves, cactiform stem succulence, and tubers. We then tested the relationship between climatic conditions and succulence, using comparative methods that account for shared evolutionary history. We confirm that plant water storage is associated with the two components of aridity, temperature, and precipitation. Cactiform stem succulence, however, is not prevalent in the driest environments, countering the widely held view of cactiforms as desert icons. Instead, leaf succulence and tubers are significantly associated with the lowest levels of precipitation. Our findings provide a clear link between broad-scale climatic conditions and adaptation in land plants, and new insights into the climatic conditions favoring different forms of succulence. This evidence for adaptation to climate raises concern over the evolutionary future of succulent plants as they, along with other organisms, face anthropogenic climate change., (© The Author(s) 2014. Published by Oxford University Press, on behalf of the Society of Systematic Biologists. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Euphorbia is among the largest genera of angiosperms, with about 2000 species that are renowned for their remarkably diverse growth forms. To clarify phylogenetic relationships in the genus, we used maximum likelihood, bayesian, and parsimony analyses of DNA sequence data from 10 markers representing all three plant genomes, averaging more than 16kbp for each accession. Taxon sampling included 176 representatives from Euphorbioideae (including 161 of Euphorbia). Analyses of these data robustly resolve a backbone topology of four major, subgeneric clades--Esula, Rhizanthium, Euphorbia, and Chamaesyce--that are successively sister lineages. Ancestral state reconstructions of six reproductive and growth form characters indicate that the earliest Euphorbia species were likely woody, non-succulent plants with helically arranged leaves and 5-glanded cyathia in terminal inflorescences. The highly modified growth forms and reproductive features in Euphorbia have independent origins within the subgeneric clades. Examples of extreme parallelism in trait evolution include at least 14 origins of xeromorphic growth forms and at least 13 origins of seed caruncles. The evolution of growth form and inflorescence position are significantly correlated, and a pathway of evolutionary transitions is supported that has implications for the evolution of Euphorbia xerophytes of large stature. Such xerophytes total more than 400 species and are dominants of vegetation types throughout much of arid Africa and Madagascar., (Published by Elsevier Inc.)

Euphorbia (Euphorbiaceae) comprises over 2150 species and is thus the second-largest genus of flowering plants. In Europe, it is represented by more than 100 species with highest diversity in the Mediterranean area; the majority of taxa belong to subgenus Esula Pers., including about 500 taxa. The few available phylogenetic studies yielded contrasting results regarding the monophyly of subg. Esula, and the phylogenetic relationships among its constituents remain poorly understood. We have sampled DNA sequences from the nuclear ribosomal internal transcribed spacer (ITS) and the plastid trnT-trnF region from about 100, predominantly European taxa of subg. Esula in order to infer its phylogenetic history. The plastid data support monophyly of subg. Esula whereas the ITS phylogeny, which is generally less resolved, is indecisive in this respect. Although some major clades have partly incongruent positions in the ITS and plastid phylogenies, the taxonomic content of the major terminal clades is congruent in both trees. As traditional sectional delimitations are largely not corroborated, an improved classification is proposed. Character state reconstruction illustrates that the annual life form developed independently several times in different clades of subgenus Esula from perennial ancestors, and that several morphological traits used in previous classifications of Euphorbia developed in parallel in different lineages., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Premise of the Study: The Chamaesyce clade of Euphorbia is the largest lineage of C(4) plants among the eudicots, with 350 species including both narrow endemics and cosmopolitan weeds. We sampled this group worldwide to address questions about subclade relationships, the origin of C(4) photosynthesis, the evolution of weeds, and the role of hybridization and long-distance dispersal in the diversification of the group. •, Methods: Two nuclear (ITS and exon 9 of EMB2765) and three chloroplast markers (matK, rpl16, and trnL-F) were sequenced for 138 ingroup and six outgroup species. Exon 9 of EMB2765 was cloned in accessions with >1% superimposed peaks. •, Key Results: The Chamaesyce clade is monophyletic and consists of three major subclades [1(2,3)]: (1) the Acuta clade, containing three North American species with C(3) photosynthesis and C(3)-C(4) intermediates; (2) the Peplis clade, mostly North American and entirely C(4); and (3) the Hypericifolia clade, all C(4), with both New World and Old World groups. Incongruence between chloroplast and ITS phylogenies and divergent cloned copies of EMB2765 exon 9 suggest extensive hybridization, especially in the Hawaiian Islands radiation. •, Conclusions: The Chamaesyce clade originated in warm, arid areas of North America, where it evolved C(4) photosynthesis. From there, it diversified globally with extensive reticulate evolution and frequent long-distance dispersals. Although many species are weedy, there are numerous local adaptations to specific substrates and regional or island radiations, which have contributed to the great diversity of this group.

To examine the generality of population-level impacts of ancient vicariance identified for numerous arid-adapted animal taxa along the Baja peninsula, we tested phylogeographical hypotheses in a similarly distributed desert plant, Euphorbia lomelii (Euphorbiaceae). In light of fossil data indicating marked changes in the distributions of Baja floristic assemblages throughout the Holocene and earlier, we also examined evidence for range expansion over more recent temporal scales. Two classes of complementary analytical approaches - hypothesis-testing and hypothesis-generating - were used to exploit phylogeographical signal from chloroplast DNA sequence data and genotypic data from six codominant nuclear intron markers. Sequence data are consistent with a scenario of mid-peninsular vicariance originating c. 1 million years ago (Ma). Alternative vicariance scenarios representing earlier splitting events inferred for some animals (e.g. Isthmus of La Paz inundation, c. 3 Ma; Sea of Cortez formation, c. 5 Ma) were rejected. Nested clade phylogeographical analysis corroborated coalescent simulation-based inferences. Nuclear markers broadened the temporal spectrum over which phylogeographical scenarios could be addressed, and provided strong evidence for recent range expansions along the north-south axis of the Baja peninsula. In contrast to previous plant studies in this region, however, the expansions do not appear to have been in a strictly northward direction. These findings contribute to a growing appreciation of the complexity of organismal responses to past climatic and geological changes - even when taxa have evolved in the same landscape context.