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Oxalis subg. Thamnoxys is a mostly South American group of Oxalis encompassing almost 80 species from tropical habitats that are currently separated into nine sections based on morphology and geographic distributions. In this study, we investigated whether Oxalis subg. Thamnoxys and its sections are monophyletic. DNA sequences of the nrITS, trnL-trnL-trnF , and petA-psbJ from 92 specimens of Oxalis (55 from O. subg. Thamnoxys , 37 from O. subg. Oxalis , and five outgroup taxa) were used to investigate phylogenetic relationships among its nine sections. Nuclear and plastid molecular markers were subjected to maximum likelihood and Bayesian inference analyses individually and in a combined data matrix. Our phylogenetic trees recovered O. subg. Thamnoxys as monophyletic only if O. praetexta , previously included in O. sect. Robustae , is transferred to O. subg. Oxalis. The remaining samples of the subgenus emerged in a clade with full bootstrap and posterior probability support. Within it, O. sect. Holophyllum was the only section that was recovered as monophyletic, whereas the remaining sections were not, either because of sampling a single species of each (O. sect. Foliosae , Hedysaroideae , and Phyllodoxys), to the unexpected placement of O. goyazensis (O. sect. Robustae) in O. sect. Psoraleoideae , or to the sister relationship between O. densifolia (O. sect. Foliosae) with O. pyrenea var. macrochaeta (O. sect. Thamnoxys), suggesting the need of revaluating some specific affinities and updating sectional circumscriptions. This phylogenetic study with an improved sampling of O. subg. Thamnoxys is the first step towards an updated classification of the subgenus and for interpreting both its morphological diversification and biogeographic history in South America. [ABSTRACT FROM AUTHOR]

Background The Atlantic Forest is one of the most threatened biomes in the world. Despite that, this biome still includes many areas that are poorly known floristically, including several protected areas, such as the "Floresta Nacional do Rio Preto" ("Flona do Rio Preto"), located in the Brazilian State of Espírito Santo. This study used a published vascular plant species list for this protected area from the "Catálogo de Plantas das Unidades de Conservação do Brasil" as the basis to synthesise the species richness, endemism, conservation and new species occurrences found in the "Flona do Rio Preto". New information The published list of vascular plants was based on field expeditions conducted between 2018 and 2020 and data obtained from herbarium collections available in online databases. Overall, 722 species were documented for the "Flona do Rio Preto", 711 of which are native to Brazil and 349 are endemic to the Atlantic Forest. In addition, 60 species are geographically disjunct between the Atlantic and the Amazon Forests. Most of the documented species are woody and more than 50% of these are trees. Twenty-three species are threatened (CR, EN and VU), while five are Data Deficient (DD). Thirty-two species are new records for the State of Espírito Santo. Our results expand the knowledge of the flora of the Atlantic Forest and provide support for the development of new conservation policies for this protected area. [ABSTRACT FROM AUTHOR]

Changes in phenological events have been vastly documented in face of recent global climate change. These studies are concentrated on temperate plants, and the responses of tropical species are still little understood, likely due to the lack of long-term phenological records in the tropics. In this case, the use of herbarium specimens to gather phenological data over long periods and wide geographic areas has emerged as a powerful tool. Here, we used four Melastomataceae species endemic to the Brazilian Atlantic Forest to evaluate phenological patterns and alterations as responses to recent climate changes. Phenological data were gathered from Reflora Virtual Herbarium specimens collected between 1920 and 2018, and analyzed with circular statistics applied to the intervals 1920–1979, 1980–1999, and 2000–2018. The effects of temperature range, average temperature, precipitation, and photoperiod on flowering and fruiting of each species were tested using multiple linear regressions. Through circular statistics, we detected changes, mostly delays, in the flowering of Miconia quinquedentata, Pleroma clavatum and P. trichopodum, and in the fruiting of M. acutiflora, P. clavatum and P. trichopodum. We also found that flowering and fruiting occurrence were related to local climatic conditions from months prior to the collections. We found marked phenological variations over the decades and also that these variations are associated to global climate change, adding up to the large body of evidence from higher latitudes. Our results also support herbarium collections as an important source for long-term tropical phenological studies. The lack of consistent patterns of responses among the four species (e.g. fruiting delayed two months in P. clavatum and advanced one month in M. acutiflora) suggests that climate change has unequal effects across tropical forests. This highlights the urgent need for further research to understand and forecast the ecological implications of these changes in global ecosystems processes. [ABSTRACT FROM AUTHOR]

• Our results highlight the importance of the number of locules in Myrcia classification. • The widespread and taxonomically complex Myrcia guianensis is non-monophyletic. • Myrcia sect. Aguava appears to have originated in the Cerrado. • Transitions from Cerrado to humid forests occurred in the evolution of M. sect. Aguava. • Combination of NGS and Sanger data is possible and generates robust phylogenetic trees. Myrcia is one of the largest exclusively Neotropical angiosperm genera, including ca. 800 species divided into nine sections. Myrcia sect. Aguava is one of most complex sections of Myrcia due to high morphological variation and wide distribution range of some species, including M. guianensis , with distribution throughout South America and a complex taxonomic history. We used complete plastid DNA sequences data generated using next-generation sequencing of 45 terminals, mostly from Myrcia sect. Aguava. These data were combined with five target DNA regions (ITS, psbA-trnH , trnL-trnF , trnQ-rps16 , ndhF) of additional terminals to increase taxonomic coverage. Phylogenetic analyses were conducted using a maximum likelihood approach, and divergence times and ancestral range distributions were estimated. Myrcia sect. Aguava is monophyletic and exclusively comprises species with trilocular ovaries but has no relationship with other groups within Myrcia that possess trilocular ovaries. Three main lineages that correspond to geographical distribution are recognized within Myrcia sect. Aguava. Multiple accessions reveal a non-monophyletic Myrcia guianensis and stress the biogeographical structure inside the group. Myrcia sect. Aguava had a probable mid-Miocene origin in the Cerrado, but lineages that persisted there diversified only more recently, when the present-day vegetation started to stabilize. Posterior migrations to Atlantic Forest, Amazon and Caribbean occurred at the end of Miocene, evidencing transitions from open and dry to forested and more humid areas that are less frequent in the Neotropics. Overall, it is observed that related lineages remained in ecologically similar environments. Future perspectives on Myrcia and Myrteae in the phylogenomic era are also discussed. [ABSTRACT FROM AUTHOR]

Oxalis sect. Holophyllum (Oxalidaceae) is a small group of species that is endemic to the Brazilian Atlantic Forest in the states of Rio de Janeiro, Minas Gerais, Espírito Santo, and Bahia. Species of the section can be recognized by their unifoliolate leaves, one-seeded carpels, and the common presence of dorsiventrally flattened (and sometimes winged) peduncles and/or petioles. Circumscriptions of the currently accepted species needed to be revaluated, as the overlap in several features have blurred limits among morphologically similar taxa. In this study we evaluate the monophyly and phylogenetic relationships among species of O. sect. Holophyllum, and provide an updated taxonomic study of the section, aiming at improving species circumscriptions and facilitating species-level identification. For this task, we analyzed samples from herbaria and carried out fieldwork to observe the plants in loco, collect samples, and gather material for DNA extraction, amplification, and sequencing. Bayesian and maximum likelihood phylogenetic analyses were performed using sequences from three markers: nrITS, and plastid trnL-trnF, and petA-psbJ from 13 of the 17 currently accepted species, which corroborate the monophyly of the section. Among the species of O. sect. Holophyllum, ten are newly described here at species level: O. adpressipila Fiaschi & Bilk (based on O. kuhlmannii Lourteig var. adpressipila Lourteig), O. capixaba Fiaschi & Bilk, O. cornicarpa Fiaschi, O. inopinata Fiaschi & Bilk, O. itamarajuensis Fiaschi & Bilk (based on O. alata Mart. ex Zucc. var. hirta Lourteig), O. leonii Fiaschi & Bilk, O. occulta Fiaschi & Bilk, O. retrorsa Fiaschi & Bilk, O. sciophila Fiaschi & Bilk, and O. septentrionalis Fiaschi & Bilk. Lectotypes are chosen for nine names, and an epitype for O. impatiens Vell. An identification key to all species is provided, as well as descriptions, illustrations, geographic distribution maps, and preliminary conservation statuses following IUCN guidelines. Oxalis sect. Holophyllum (Oxalidaceae) é um pequeno grupo de espécies endêmicas à Mata Atlântica dos estados do Rio de Janeiro, Minas Gerais, Espírito Santo e Bahia. Espécies da seção podem ser reconhecidas pelas folhas unifolioladas, carpelos unisseminados, e geralmente pela presença de pedúnculos e/ou pedicelos achatados dorsiventralmente ou, às vezes, alados. As circunscrições das espécies atualmente aceitas precisam ser reavaliadas, já que a sobreposição observada em vários caracteres mascara limites entre táxons morfologicamente similares. Neste estudo nós investigamos o monofiletismo e as relações filogenéticas entre espécies de O. sect. Holophyllum e fornecemos uma atualização taxonômica da seção, com o intuito de aprimorar as circunscrições das espécies e facilitar a sua identificação. Para atingir esses objetivos, nós analisamos amostras de herbários e conduzimos expedições a campo para observar as plantas in loco, coletar amostras e recolher materiais para a extração, amplificação e sequenciamento de DNA. Análises filogenéticas bayesianas e de máxima verossimilhança foram conduzidas a partir de sequências do ITS (nuclear) e do trnL-trnF e petA-psbJ (plastidiais) de 13 das 17 espécies atualmente aceitas, o que corroborou o monofiletismo da seção. Entre as espécies de O. sect. Holophyllum, dez são pela primeira vez descritas em nível específico: O. adpressipila Fiaschi & Bilk (baseada em O. kuhlmannii Lourteig var. adpressipila Lourteig), O. capixaba Fiaschi & Bilk, O. cornicarpa Fiaschi, O. inopinata Fiaschi & Bilk, O. itamarajuensis Fiaschi & Bilk (baseada em O. alata Mart. ex Zucc. var. hirta Lourteig), O. leonii Fiaschi & Bilk, O. occulta Fiaschi & Bilk, O. retrorsa Fiaschi & Bilk, O. sciophila Fiaschi & Bilk e O. septentrionalis Fiaschi & Bilk. Lectótipos são escolhidos para nove nomes e um epítipo para O. impatiens Vell. Uma chave de identificação para todas as espécies é fornecida, bem como descrições, ilustrações, mapas de distribuição geográfica e análises preliminares do status de conservação segundo as normas da IUCN. [ABSTRACT FROM AUTHOR]

• The V. polycephala leaf has a specific type of trichome, unprecedented for the genus. • Some anatomical traits of V. polycephala leaf may be adaptations to xeric environment. • Leaf anatomy can reveal important novelties for taxonomic studies. Varronia polycephala is a medicinal plant used as a substitute of V. curassavica (the popular "erva baleeira") in some traditional communities. This paper aims to describe and illustrate the leaf anatomy of V. polycephala. The results show that V. polycephala presents a distinct type of non-glandular trichome in abundance on the abaxial leaf surface, as well as a single type of glandular trichome on the same surface. Other characteristics observed in V. polycephala include non-glandular trichomes with cystoliths, crystal sand idioblasts, shape of the petiole in cross section, type of vascular bundles and ring collenchyma in the petiole. Histochemical results suggest similarities with V. curassavica , showing the pharmacological potential of V. polycephala. Possible ecological functions of structures and substances are discussed. [ABSTRACT FROM AUTHOR]

Myrteae (c. 2500 species; 51 genera) is the largest tribe of Myrtaceae and an ecologically important groups of angiosperms in the Neotropics. Systematic relationships in Myrteae are complex, hindering conservation initiatives and jeopardizing evolutionary modelling. A well-supported and robust phylogenetic hypothesis was here targeted towards a comprehensive understanding of the relationships within the tribe. The resultant topology was used as a base for key evolutionary analyses such as age estimation, historical biogeography and diversification rate patterns. One nuclear ( ITS ) and seven chloroplast ( psbA-trnH , matK , ndhF , trnl - trnF , trnQ - rps16 , rpl16 and rpl32 - trnL ) DNA regions for 115 taxa representing 46 out of the 51 genera in the tribe were accessed and analysed using maximum likelihood and Bayesian inference tools for phylogenetic reconstruction. Dates of diversification events were estimated and contrasted using two distinct fossil sets (macro and pollen) in BEAST. The subsequent dated phylogenies were compared and analysed for biogeographical patterns using BioGeoBEARS and diversification rates using BAMM. Myrteae phylogeny presents strong statistical support for three major clades within the tribe: Australasian group, Myrtus group and Main Neotropical Lineage. Dating results from calibration using macrofossil are an average of 20 million years older and show an early Paleocene origin of Myrteae, against a mid-Eocene one from the pollen fossil calibration. Biogeographic analysis shows the origin of Myrteae in Zealandia in both calibration approaches, followed by a widespread distribution throughout the still-linked Gondwana continents and diversification of Neotropical endemic lineages by later vicariance. Best configuration shift indicates three points of acceleration in diversification rates, all of them occurring in the Main Neotropical Lineage. Based on the reconstructed topology, several new taxonomic placements were recovered, including: the relative position of Myrtus communis , the placement of the Blepharocalyx group, the absence of generic endemism in the Caribbean, and the paraphyletism of the former Pimenta group. Distinct calibration approaches affect biogeography interpretation, increasing the number of necessary long distance dispersal events in the topology with older nodes. It is hypothesised that biological intrinsic factors such as modifications of embryo type and polyploidy might have played a role in accelerating shifts of diversification rates in Neotropical lineages. Future perspectives include formal subtribal classification, standardization of fossil calibration approaches and better links between diversification shifts and trait evolution. [ABSTRACT FROM AUTHOR]

[Display omitted] • A large portion of Miconia from the Atlantic Forest were assigned to a new section and supersection. • Glomerulate inflorescences in Miconia were derived from scorpioid ones. • Indument on young branches and leaves are useful for supersection and sections circumscriptions. • Miconia biogeography suggests independent dispersals to Atlantic Forest. Miconia is among the largest plant genera in the Neotropics and a taxonomically complex lineage. Indeed, molecular phylogenetic data shows that none of its traditionally accepted sections are monophyletic, preventing taxonomic advances within the genus. Miconia is the largest plant genus in the Brazilian Atlantic Forest, including three main lineages, the Leandra s.s. clade (ca. 215 spp.), the Miconia sect. Chaenanthera (24 spp.), and the Miconia discolor clade (estimated 77 spp.). Out of these lineages, the Miconia discolor clade is the only currently lacking phylogenetic data, complicating its taxonomy. In this study, we reconstruct the phylogeny of the Miconia discolor clade, using three plastid (atp F-H, psb K-I, and psa I- acc D) and two nuclear (ETS and ITS) markers. We sampled 60 out of the 77 species of the group, representing 78% of its diversity. Taxa were selected considering their distribution, morphology, and previous phylogenetic knowledge. We used the newly reconstructed phylogeny to better understand phylogenetic relationships among Atlantic Forest species and morphologically similar taxa, and to propose a new infrageneric classification for the Miconia discolor clade: the Miconia supersection Discolores. We further studied the evolution of seven morphological characters using a Maximum Likelihood approach, and estimated the ancestral range distribution of various lineages in order to understand the biogeographic history of this clade. We found that dichasial inflorescences represent the ancestral condition within Miconia , subsequently giving rise to scorpioid and glomerulate inflorescences in the studied group. We describe Miconia supersect. Discolores, originated in the Amazon region, which is recognized by a dense layer of branched tricomes covering young branches and non-dichasial inflorescences, including three main lineages: (i) Miconia sect. Albicantes , characterized by persistent bracts and arachnoid indument on the abaxial surface of leaves, mainly distributed in the Amazon basin; (ii) Miconia sect. Discolores , characterized by caducous calyx lobes and glomerulate inflorescences, centered in the Atlantic Forest; and (iii) Miconia sect. Multispicatae , characterized by leaves not completely covered with indument, and capitate stigma, mainly distributed in the Atlantic Forest. All three sections and the supersection originated in the Neogene, between the Late Miocene and the Early Pliocene. [ABSTRACT FROM AUTHOR]