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Campanula L. is among the genera with the highest number of endemics in the Caucasus ecoregion. A group of attractive alpine and subalpine perennial rosette plants with short single-flowered stems centred in the Caucasus has been treated as Campanula subg. Scapiflorae or at other ranks, with considerably varying circumscription and classification. Molecular phylogenetic analysis of three plastid DNA regions (trnK/matK, petD, rpl16) of a strongly extended sampling, comprising 23 of the 27 commonly accepted taxa (85%) with 330 accessions built on and guided by the results of our previous study of the group, confirmed the polyphyly of C. subg. Scapiflorae in any of its circumscriptions. The core clade of the group comprises exclusively endemics and near-endemics of the Caucasus and is treated here as C. sect. Tridentatae in a revised circumscription. The phylogenetic relationships of the disparate other elements of the Scapiflorae group are outlined. [ABSTRACT FROM AUTHOR]

Caryophyllaceae with a cushion-like life form occur with a large number of species at the higher altitudes of the Andes (3500–5000 m) and have evolved convergently in several different lineages. Based on molecular phylogenetic analysis it is shown that members of the former genera Plettkea and Pycnophyllopsis, but also certain species previously classified as Arenaria constitute a subclade nested within the monophyletic genus Stellaria. Both plastid (trnK-matK-psbA + trnL-F) and nuclear (nrITS) trees converged on such a highly supported 'Plettkea' clade. Morphologically, the members of the 'Plettkea' subclade of Stellaria are further characterized by reduced to completely absent petals and seeds with a more or less conspicuous tuberculate testa. This clade is described as S. sect. Plettkea (Mattf.) Montesinos & Borsch. Species-level relationships within S. sect. Plettkea are also congruently inferred by plastid and nuclear genomic compartments, with three further sublineages recognized: Altogether, our detailed taxonomic revision showed that the 'Plettkea' clade in fact constitutes an Andean radiation of 21 species within Stellaria, four of which are described as new to science. Earlier treatments indicated just a few species with a putative placement. The results of this investigation underscore the importance of fieldwork and integrated molecular-morphological approaches to assess the species diversity in Andean plant groups. In addition to the phylogenetic analysis, we provide a taxonomic backbone including all names and types, descriptions and information on distribution and ecology and a key for identification. Regarding the next relatives of the S. sect. Plettkea clade, our plastid trees depict the 'Nitentes' clade of Stellaria as sister, whereas nrITS instead suggests a sister group relationship of the 'Nitentes' with the speciose 'Larbreae' clade. Our inferred relationships of major clades further deviate from published molecular trees by indicating an early branching position of the 'Petiolares' clade. Citation: Montesinos-Tubée D. B. & Borsch T. 2023: Molecular phylogenetics and morphology reveal the Plettkea lineage including several members of Arenaria and Pycnophyllopsis to be a clade of 21 South American species nested within Stellaria (Caryophyllaceae, Alsineae) Version of record first published online on 21 December 2023 ahead of inclusion in December 2023 issue. Las Caryophyllaceae, con forma de vida en matas o almohadillas, se encuentran en las mayores altitudes de los Andes (3500–5000 m) con un gran número de especies y han tenido una evolución convergente en diversos linajes. Análisis filogenéticos moleculares, recuperan un subclado anidado dentro del género monofilético Stellaria, constituido por los miembros previamente clasificados en Plettkea y Pycnophyllopsis y especies clasificadas hasta ahora en Arenaria. Tanto los árboles de plástidos (trnK-matK-psbA + trnL-F) como los nucleares (nrITS) convergen en un clado de 'Plettkea' altamente apoyado estadísticamente. Morfológicamente, los miembros del subclado 'Plettkea' de Stellaria se caracterizan, además, por compartir pétalos reducidos o completamente ausentes y semillas con un tegumento tuberculado más o menos conspicuo. El subclado se valida como S. sect. Plettkea (Mattf.) Montesinos & Borsch. Las relaciones a nivel de especie dentro de esta sección también se infieren congruentemente por compartimentos genómicos plastidiales y nucleares, con tres sublinajes. En conjunto, nuestra detallada revisión taxonómica mostró que el clado Plettkea constituye una radiación andina de 21 especies dentro de Stellaria, cuatro de las cuales se describen como nuevas para la ciencia. Tratamientos anteriores indicaban sólo unas pocas especies con una ubicación putativa. Los resultados de esta investigación destacan la importancia del trabajo de campo y la integración de métodos moleculares y morfológicos para evaluar la diversidad de especies en los grupos de plantas andinas. Además del análisis filogenético, proporcionamos una columna vertebral taxonómica que incluye todos los nombres y datos de los tipos nomenclaturales. Se proporcionan descripciones e información sobre distribución y ecología así como una clave para identificarlas. Con respecto a los parientes próximos del clado de S. sect. Plettkea, nuestros árboles de plástidos muestran al clado 'Nitentes' de Stellaria como hermano, mientras que nrITS sugiere más bien una relación de grupo hermano de los 'Nitentes' con el clado 'Larbreae'. Las relaciones inferidas de los clados principales se desvían aún más de los árboles moleculares publicados previamente, al indicar una posición de ramificación temprana del clado 'Petiolares'. [ABSTRACT FROM AUTHOR]

Background and Aims The genus Buxus has high levels of endemism in the Caribbean flora, with ~ 50 taxa. In Cuba, 82 % grow on ultramafic substrates and 59 % are nickel (Ni) accumulators or Ni hyperaccumulators. Hence it is an ideal model group to study if this diversification could be related to adaptation to ultramafic substrates and to Ni hyperaccumulation. Methods We generated a well-resolved molecular phylogeny, including nearly all of the Neotropical and Caribbean Buxus taxa. To obtain robust divergence times we tested for the effects of different calibration scenarios, and we reconstructed ancestral areas and ancestral character states. Phylogenetic trees were examined for trait-independent shifts in diversification rates and we used multi-state models to test for state-dependent speciation and extinction rates. Storms could have contributed to Cuba acting as a species pump and to Buxus reaching other Caribbean islands and northern South America'. Key Results We found a Caribbean Buxus clade with Mexican ancestors, encompassing three major subclades, which started to radiate during the middle Miocene (13.25 Mya). Other Caribbean islands and northern South America were reached from ~3 Mya onwards. Conclusions An evolutionary scenario is evident in which Buxus plants able to grow on ultramafic substrates by exaptation became ultramafic substrate endemics and evolved stepwise from Ni tolerance through Ni accumulation to Ni hyperaccumulation, which has triggered species diversification of Buxus in Cuba. Storms could have contributed to Cuba acting as a species pump and to Buxus reaching other Caribbean islands and northern South America'. [ABSTRACT FROM AUTHOR]

Using the genus Casearia, we assessed the status of nested singletons: individual specimens corresponding to accepted species but in molecular trees appearing nested within clades of closely related species. Normally, such cases would be left undecided, while on the other hand, timely taxonomic decisions are required. We argue that morphological, chorological, and ecological data can be informative to illuminate patterns of speciation. Their use can provide a first step in testing taxon concepts at species level. We focused on five cases of nested singletons in trees of the genus Casearia. We employed PCA and cluster analysis to assess phenotypic differentiation. Using geocoordinates, we calculated niche space differentiation based on 19 bioclim variables, by means of PCA and niche equivalency and similarity tests and generated dot maps. We found that the singletons were morphologically distinctive in two of the five cases (Casearia selloana and C. manausensis), relatively distinctive in two other cases (C. zizyphoides and C. mariquitensis), and partially overlapping in the last case (C. grandiflora). For two cases (C. mariquitensis and C. selloana), ecological niche space was broadly overlapping, in two cases it was found broadly nested (C. grandiflora and C. zizyphoides), and in one case narrowly nested (C. manausensis), but in no case niche differentiation was observed. Niche overlap, similarity and equivalency showed corresponding patterns. Given these data, one would interpret C. selloana and C. manausensis as presumably well‐distinguished taxa, their narrow distribution ranges suggesting recently emerging lineages. The other three cases are not clearcut. Morphological data would suggest particularly C. grandiflora conspecific with C. arborea, but differences in the distribution are intriguing. Our approach would reject the notion of potential synonymy based on nested phylogenetic placement for at least two of the five cases. The other case also shows no complete lack of differentiation which would support synonymy. [ABSTRACT FROM AUTHOR]

Premise of research. The Caribbean is an important area of species diversity within the large pantropical genus Phyllanthus. With the goal of illuminating the evolutionary origins of Caribbean Phyllanthus , we undertook a phylogenetic analysis significantly increasing previous samplings of the genus in the Neotropics. We reconstructed the evolution of selected morphological characters and evaluated the implications of our results in light of the representation of Caribbean and Neotropical species in the infrageneric classification of the genus. Methodology. We estimated phylogentic trees using parsimony, Bayesian, and likelihood approaches based on plastid and nuclear sequence data sets. These represented 78 taxa from the Neotropics, most of which were generated for this study, as well as most other subgenera and sections of Phyllanthus and other genera of Phyllanthaceae. Four vegetative and four floral morphological characters were assessed for the whole study group. Ancestral character states were reconstructed using BayesTraits. Pivotal results. Plastid and nuclear partitions agree on a highly supported Caribbean clade that contains the vast majority of the species from this region as being part of a large Neotropical clade. Another small Caribbean clade is found nested among African linages. Although morphological characters exhibit some level of homoplasy, some trends are evident, for example, in the large Neotropical clade. Conclusions. The majority of species in the Caribbean belong to a single clade that has evolved from Neotropical ancestors. This is well circumscribed with morphology and corresponds to subgenus Xylophylla , the concept of which is adjusted here to be monophyletic. The existence of a small Caribbean clade related to African species marks a noteworthy case of Caribbean plant origin. Although phyllanthoid branching is not a synapomorphy for Phyllanthus s.l. (including Breynia , Glochidion , and Sauropus), combinations of vegetative and floral characters allow a clear assignment to the Phyllanthus s.l. clade. [ABSTRACT FROM AUTHOR]

The genus Tamarix (Tamaricaceae) is a lineage of shrubs and trees with leaves reduced to scales and numerous species adapted to moist and often saline soils in arid and semi-arid climates. Extensive morphological variation and hybridization complicate species delimitation and identification. Based on both morphological and DNA sequence characters, Tamarix humboldtiana Akhani, Borsch & N. Samadi is described as a new species from S Iran. Phylogenetic analysis of plastid rpl16 intron and trnG-trnS spacer sequences depicts a sister group relationship of its unique plastid haplotype to T. tetrandra, whereas nuclear ITS sequence data show close affinities to T. kotschyi. The new species differs from T. kotschyi by distinctly pedicellate, 5-merous flowers and vaginate-amplexicaul leaves. The stem and foliar anatomy and the epidermal micromorphology provide additional characters differentiating the new species from T. kotschyi. The gametic chromosome number of n = 12 reflects that of most of other species of the genus. Tamarix humboldtiana is a rare species living at freshwater riversides in S Iran and is according to current knowledge critically endangered. Citation: Akhani H., Samadi N., Noormohammadi A. & Borsch Th. 2019: A new species of Tamarix (Tamaricaceae) from Hormozgan Province, S Iran, supported by morphology and molecular phylogenetics. – Willdenowia 49: 127–139. doi: https://doi.org/10.3372/wi.49.49113 Version of record first published online on 17 April 2019 ahead of inclusion in April 2019 issue. [ABSTRACT FROM AUTHOR]

Iresine is a neotropical genus of the Amaranthaceae with most of the species diversity in Mexico and Mesoamerica. It has suffered a complex classification history with considerably diverging views on the genus concept. We have carried out a phylogenetic analysis of Iresine and allied genera using sequence data of combined plastid introns (including the matK CDS) and spacers as well as ITS, and a dense sampling of species. Trees depict a clade of Iresine with Irenella and Woehleria deeply nested. This clade is sister to the remainder of Gomphrenoideae including Hebanthe and Trommsdorffia (= Pedersenia). One of two maximally supported subclades of Iresine comprises mostly species restricted to the Mexican highlands and adjacent areas, whereas the other subclade is composed of more widespread Mexican-Mesoamerican taxa. Pollen grains of Iresine and relatives were examined using high-resolution SEM, which yielded a matrix of 15 pollen characters. Ancestral character state reconstruction shows dodecahedral grains (in I. angustifolia and I. nigra) to have evolved within the Iresine clade, not involving the complete suite of character shifts associated with metareticulate pollen but just an increase of aperture diameter and a slight decrease of mesoporia width. To the contrary, four character state transformations occurred in the common ancestor of core Gomphrenoideae that led to metareticulate pollen (shifts to a distal orientation of punctae and microspines, to a sunken position of apertures relative to the distal part of mesoporia resulting in narrow mesoporia higher then wide, and a reduction in the diameter of mesoporia). The Iresine clade is characterized by pollen with well-separated ektexinous aperture membrane bodies, rounded or triangular, and gradually tapering into a single spine. For the monophyletic genus Iresine, 35 species are currently accepted. We provide a taxonomic backbone (including one new combination, one new name and several lectotypifications) that also comments on the current understanding of species delimitation. [ABSTRACT FROM AUTHOR]

Limonium (Plumbaginaceae) is a nearly cosmopolitan halophytic genus with ca. 350 species, a large number of which occurs in the Mediterranean region. We have generated a sequence dataset of several plastid (trnK intron including the matK gene, petD intron with the petB-petD spacer, trnL intron with the trnL-trnF spacer) and one nuclear region (nrITS), spanning the major lineages within the genus (102 accessions representing 76 species of Limonium) and related genera. Bayesian inference, maximum likelihood and maximum parsimony analyses converge on a Limonium clade that includes the genera Afrolimon, Eremolimon and Linczevskia. Plastid and nuclear trees congruently depict a number of major clades, most of them with a characteristic vegetative morphology and growing in specific habitats. Although the position of Afrolimon is incongruently resolved as the sister of a subclade comprising Limonium vulgare and relatives in the plastid trees versus being the sister to a Limonium sogdianum--L. bellidifolium--L. aureum clade in the nrITS tree, both genomic compartments show that Afrolimon is deeply nested in Limonium. Eremolimon is resolved as a close relative of L. sogdianum and L. ferganense based on plastid and nuclear genomic compartments. Our phylogenetic analysis resulted in an improved picture of internal relationships. Apart from the monophyletic subgenera Limonium subg. Limonium and L. subg. Pteroclados, nine wellsupported clades of L. subg. Limonium are evident, several of which are predominantly constituted by species of a certain geographic range. A subclade of IranoTuranian species (L. iranicum, L. suffruticosum and relatives) is shown to be unrelated to a L. axillare subclade, indicating an independent origin of the woody habit in these two lineages. Limonium sect. Iranolimon sect. nov. is described for the IranoTuranian woody lineage. The new combination L. sect. Circinaria comb. nov., is established for taxa sometimes included in Afrolimon. [ABSTRACT FROM AUTHOR]

Alternanthera (Amaranthaceae) is a diverse genus (80-200 species) largely restricted to the American Tropics. With Pedersenia and Tidestromia, it makes up the 'Alternantheroid clade' in Gomphrenoideae. Parsimony and Bayesian analyses of nucleotide sequences of nuclear (ITS) and plastid ( rpl16, trnL-F) and morphological characters identify that the capitate stigma of Alternanthera is a synapomorpy within the Alternantheroids. Within Alternanthera, two major clades were resolved, both of which were marked by otherwise homoplasious characters of the gynoecium: Clade A [99% jackknife (JK); 1.0 posterior probability (PP)] with nine species and Clade B (60% JK; 0.98 PP) with 22 species. Four subclades (B1-B4), strongly supported statistically, were identified in Clade B. Previous subgeneric classifications of Alternanthera appear artificial in light of our new molecular phylogenetic analyses. Most major lineages are congruently resolved by nuclear and plastid data but some incongruence between the nrITS and plastid phylogenetic trees suggests hybridization may have played a role in the rampant speciation in Alternanthera. Whereas C4 photosynthesis appears to have evolved in a single clade, the position of A. littoralis var. maritima (C3) in this clade may be explained by hybrid speciation rather than a reversal from C4 to C3. All C3-C4 intermediates belong to a different clade that also contains C3 species, but species limits, including the widely studied A. tenella, are unclear. The clade including A. tenella and A. halimifolia contains most of the species endemic to the Galápagos whereas A. nesiotes, also endemic to the islands, is nested among widespread American taxa. This suggests that the Galápagos radiation of Alternanthera may have arisen from at least two independent colonization events followed by a subsequent radiation in the former lineage. © 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, 169, 493-517. [ABSTRACT FROM AUTHOR]

Molecular phylogenetic analysis of the subfamily Chenopodioideae of the goosefoot family (Chenopodiaceae), with the addition of matK/trnK sequences to an existing trnL-F data set, indicates that Chenopodium as traditionally recognised consists of six independent lineages. One of these, the Dysphania-Teloxys clade, had already been recognised previously as a separate tribe Dysphanieae. Of the five others, Chenopodium is here re-defined in a narrow sense so as to be monophyletic. The C. polyspermum, C. rubrum and C. murale clades are successive sisters of a lineage constituted by Atripliceae s.str. plus Chenopodium s.str. Consequently, the long forgotten genera Lipandra (for C. polyspermum) and Oxybasis (for C. rubrum and relatives) are revived, and the new genus Chenopodiastrum (for C. murale and relatives) is published. The afore-mentioned five clades, taken together, are a monophylum corresponding to an enlarged tribe Atripliceae (a name that has priority over Chenopodieae). Last, the Linnaean genus Blitum (for C. capitatum and relatives), enlarged to include C. bonus-henricus, is the sister group of Spinacia in the tribe Anserineae (a name that has priority over Spinacieae). The aromatic species of Dysphania, the related genus Teloxys, as well as Cyclocoma and Suckleya form the enlarged tribe Dysphanieae. Building upon phylogenetic results, the present study provides a modern classification for a globally distributed group of plants that had suffered a complex taxonomic history due to divergent interpretation of single morphological characters for more than two hundred years. The seven genera among which the species traditionally assigned to Chenopodium are now distributed are defined morphologically and keyed out; for four of them (Blitum, Chenopodiastrum, Lipandra, Oxybasis) the component species and subspecies are enumerated and the necessary nomenclatural transfers are effected. [ABSTRACT FROM AUTHOR]