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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., (Crown Copyright © 2020. Published by Elsevier Inc. All rights reserved.)

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]

[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]