The tribe Gochnatieae is restricted to America. A recent molecular study including over 60% of the species of the tribe was carried out to untangle evolutionary relationships among the taxa. Eight ...supported clades were recovered as monophyletic genera, while Gochnatia s.l. was revealed as paraphyletic and currently restricted to the Central Andes. Gochnatia rotundifolia was not included in this phylogeny since extracted DNA from few and old collections from Brazil was unusuable. Since Cabrera's treatment of Gochnatia s.l., this species has received special attention due to its distinct morphological characters when compared with the other monophyletic genera of Gochnatieae. Therefore, this paper aims to provide new evidence that supports Gochnatia rotundifolia to be described as a separate monospecific genus based on a morphological study and a maximum parsimony (MP) analysis. A total of 21 species were studied. The leaf venation was analysed using digital X-ray capture (VIVA–Varian Image viewing & Aquisition). Seventeen morphological characters obtained from vegetative and floral parts of the plants were included in the data matrix. Our results reinforce the placement of Gochnatia rotundifolia within the tribe Gochnatieae. Gochnatia rotundifolia is consistently recovered in a clade as sister to the Cnicothamnus-Richterago group. The species differs from the other genera of the tribe by an actinodromous basal leaf venation with three primary veins, and pappus elements composed by (50–)60–75 bristles, sometimes almost flat setae, arranged in 2 or 3 series, unequal in length. Our results support Gochnatia rotundifolia as the sole species Vickia rotundifolia comb. nov. in a new genus of Gochnatieae, Vickia gen. nov. The new genus is described, illustrated, and a generic identification key for the tribe Gochnatieae is provided.
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•The first study to utilize microfluidic PCR for high-throughput sequence library preparation in Compositae.•Cyclolepis is no longer insertae sedis, but now confidently placed in ...Gochnatieae with strong statistical support.•Gochnatieae is confirmed to be monophyletic and comprises ten genera and 95 species; a complete species checklist is provided.•Gochnatieae originated in Eastern South America about 53 my and subsequent dispersal occurred from the current central Andes throughout its present range.•Several states associated with complex plant reproductive traits are derived in Gochnatieae; Moquiniastrum is a model genus to study plant sexual system evolution.
Understanding the evolution of the tribe Gochnatieae (Compositae) has been the subject of considerable effort in the past decade. This is due to the key position of this tribe in the phylogeny of the sunflower family and the corresponding implications for biogeographic and morphological evolution of Compositae. Previous studies have confirmed the monophyly of this tribe as well as most of the genera that belong to it. However, phylogenetic resolution of Gochnatieae at both the genus- and species-level has remained poor. A subset of new phylogenomic loci used in this study has proven effective and has improved phylogenetic resolution in this group. The results of this work demonstrate Gochnatieae is a well-supported clade comprised of nine genera (Anastraphia, Cnicothamnus, Cyclolepis, Gochnatia, Moquiniastrum, Nahuatlea, Pentaphorus, Richterago, Tehuasca). One recently described genus, Vickia, was not included in this study; but its placement in Gochnatieae as a tenth genus in the tribe is well-justified. The monospecific Cyclolepis, which had been circumscribed within the tribe since its inception but was subsequently removed and designated as incertae sedis since 2014, is also shown to belong to Gochnatieae. We confirmed the monophyletic Moquiniastrum with two well-supported subclades. Ancestral area reconstruction analyses show that Gochnatieae originated in Eastern South America about 53 my. Apparently, except for Cyclolepis and Richterago, the ancestors of the other genera of Gochnatieae originated about 44 my from an area that now corresponds to the central Andes. The presence of the genera in the Chaco phytogeographic province, central Chile, and Mexico-United States-Caribbean is a result of dispersal from the central Andes. The ancestral distribution of Moquiniastrum corresponds to a large area comprising Eastern South America and the current central Andes, about 32 my. Ancestral character state reconstruction that included four characters indicates several states associated with complex plant reproductive biology such as gynodioecy, gynomonoecy, and polygamodioecy are derived in Gochnatieae as are heterogamous capitula (in Moquiniastrum and Richterago), dimorphic and subdimorphic corollas (in Cnicothamnus, Moquiniastrum, and Richterago), and the presence of marginal female corollas (in Moquiniastrum and Richterago). Within Moquiniastrum, two subclades (Densicephalum and Polymorphum) exhibit divergent patterns of trait evolution associated with these reproductive characters which suggests this genus can serve as a model to understand the sexual system evolution in plants.
Climbers germinate on the ground but need external support to sustain their stems, which are maintained attached to supports through modified organs, that is, climbing mechanisms. Specialized ...climbing mechanisms have been linked to higher diversification rates. Also, different mechanisms may have different support diameter restrictions, which might influence climbers' spatial distribution. We test these assumptions by linking climbing mechanisms to the spatiotemporal diversification of neotropical climbers. A dataset of climbing mechanisms is presented for 9071 species. WCVP was used to standardize species names, map geographical distributions, and estimate diversification rates of lineages with different mechanisms. Twiners appear concentrated in the Dry Diagonal of South America and climbers with adhesive roots in the Chocó region and Central America. However, climbing mechanisms do not significantly influence the distribution of neotropical climbers. Also, we found no strong support for correlations between specialized climbing mechanisms and higher diversification rates. Climbing mechanisms do not strongly impact the spatiotemporal diversification of neotropical climbers on a macroevolutionary scale. We argue that the climbing habit is a synnovation, meaning the spatiotemporal diversification it promotes is due to the sum effect of all the habit's traits rather than isolated traits, such as climbing mechanisms.
Background and aims - Generic limits of the tropical tribe Gardenieae (Ixoroideae, Rubiaceae) have partly remained unsettled. We produced a new phylogeny of the Randia clade, with emphasis on its ...Neotropical clade comprising five genera (Casasia, Randia,
Rosenbergiodendron, Sphinctanthus, and Tocoyena). The result was subsequently used to evaluate and discuss: a) the respective monophyly of the above-mentioned genera and their interrelationships; b) relationships within Tocoyena and the evolutionary relevance of
its subgeneric classification; and c) the monophyly of the morphologically variable T. formosa.
Material and methods - We examined the phylogeny of the Randia clade based on maximum likelihood and Bayesian analyses of sequence data from two nuclear (ETS
and Xdh) and two plastid ( petB-petD and trnT-F) DNA regions from 59 individuals (including seven representatives from the remaining Ixoroideae).
Key results - The Neotropical clade of the Randia clade comprises three major lineages, the
Randia armata subclade, the Randia-Casasia subclade and the Rosenbergiodendron subclade. Neither Casasia nor Randia is monophyletic. Tocoyena is sister to Rosenbergiodendron + Sphinctanthus and is subdivided into three lineages: the
Tocoyena pittieri group, the Tocoyena guianensis group, and the core Tocoyena. Tocoyena williamsii is paraphyletic with respect to T. pittieri. Tocoyena formosa is polyphyletic and should be re-circumscribed.
Conclusions -
Our results demonstrate the monophyly of each of the relatively species-poor genera Rosenbergiodendron , Sphinctanthus, and Tocoyena, and confirm their close affinity. The serial classification of Tocoyena does not reflect the evolutionary history of the genus.
The paraphyly of T. williamsii with respect to T. pittieri, together with their morphological similarities and geographic distributions, support the inclusion of the former in the latter. Our study calls for additional phylogenetic work on Casasia and the more species-rich
genus Randia. While the respective monophyly of both genera is rejected here, future work with a broader representation of Randia is needed.
In science, standardization of terminology is crucial to make information accessible and allow proper comparison of studies’ results. Climbing plants and the climbing habit have been described in ...numerous ways, frequently with imprecise and dubious terms. We propose a standardization of terms regarding the climbing habit, with special attention to climbing mechanisms. We abide by previous suggestions that the terms “primary” and “secondary” hemiepiphyte be substituted by “hemiepiphyte” and “nomadic climber” respectively, thus emphasizing the relationship of the latter to the climbing habit. We also suggest that “climbing plant” or “climber” be used to describe plants displaying the climbing habit, and “liana” and “vine” be left for describing woody and herbaceous climbers respectively. As for climbing mechanisms, we propose an eight-category classification comprised of two major categories: passive climbing, containing scrambling, hooks or grapnels, and adhesive roots; and active climbing, containing twining, tendrils, prehensile branches, twining petioles, and twining inflorescences.
Abstract
We explored the effects of Quaternary climate changes on the campos rupestre sky island ecosystem in central and eastern Brazil studying the phylogeography of Richterago discoidea ...(Asteraceae) to better understand the effect of historical biogeographic processes on species diversification in this region. DNA sequences of nuclear (ITS) and plastid (psbA-trnH, rpl32-trnLUAG, trnKUUU-rps16 and ycf3-trnS) markers and 83 AFLP loci were used to genotype up to 90 individuals from 19 populations of R. discoidea. We investigated intraspecific genetic structure, demographic history and spatiotemporal diversification. Also, ecological niche modelling was used to infer palaeodistribution. Three lineages (without strong geographical structure) were identified in the Bayesian genetic structure analysis of 25 haplotypes, whereas AFLPs revealed two lineages with considerable levels of admixture. The origin of diversification of R. discoidea is on the Diamantina Plateau (Espinhaço Meridional, Minas Gerais), from where lineages expanded to the central highlands of Brazil during glacial periods in the Mid-Pleistocene. The current disjunct distribution is a relict of an ancient wide distribution, resulting from retraction during interglacial periods, confining populations to mountain-top sky islands that acted as refugia (Espinhaço Range and Goiás highlands). Expansion within refugium sites during the LGM blurred deeper genetic structure, and pressure of selection in ecological outliers favoured high genetic diversity outside refugia.
Resumo A tribo Eupatorieae apresenta ca. 2.200 espécies, agrupadas em 182 gêneros e 19 subtribos. No Brasil, a tribo destaca-se por apresentar o maior número de gêneros (86) e espécies (615) nas ...diversas fitofisionomias do país. O gênero Mikania, considerado um dos mais naturais e complexos da Tribo Eupatorieae, pertence à subtribo Mikaniinae e apresenta ca. 450 espécies com distribuição principalmente neotropical. No Brasil, o gênero está representado por 203 espécies, sendo 142 consideradas endêmicas. O presente trabalho teve como objetivo realizar o levantamento florístico e o estudo taxonômico das espécies do gênero Mikania (Asteraceae, Eupatorieae) na Bahia. Foram realizadas coletas em diversos municípios do estado, além de visitas a importantes herbários nacionais para o grupo (ALCB, CEPEC, HUEFS, HRB, RB, R, SPF, SP). Dos 53 nomes antes registrados para a Bahia, 14 foram excluídos e 7 novas ocorrências foram acrescentadas, totalizando 46 espécies. Apresentamos aqui uma chave de identificação, descrições de todas as espécies, além de comentários taxonômicos, biológicos e de distribuição geográfica.
Abstract The Eupatorieae tribe, one of the tribes belonging to the Alliance, presents ca. 2,200 species, grouped into 182 genera and 19 subtribes. In Brazil, the tribe stands out for having the highest number of genera (86) and species (615) in the various phytophysiognomies of the country. Mikania, considered one of the most natural and complex of the Tribe Eupatorieae, belongs to the subtribe Mikaniinae and presents ca. 450 species with mainly neotropical distribution. In Brazil, the genus is represented by 203 species, of which 142 are considered endemic. The present work had as objective to carry out the floristic survey and the taxonomic study of the species of Mikania (Asteraceae, Eupatorieae) in Bahia state. Field collections were performed in several municipalities of the state, besides to the visit to important national herbaria for the group (ALCB, CEPEC, HUEFS, HRB, RB, R, SP, SPF). Of the 53 names previously registered for Bahia, 14 were excluded and 7 new occurrences were added, totalizing 46 species. We present a key identification, descriptions of all species, as well as taxonomic, biological and geographic distribution comments.
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