Eugenia currently comprises c. 1050 species and is the largest angiosperm genus in Brazil. Recent morphological and taxonomic revision of Eugenia s.l. in light of current phylogenetic knowledge necessitates a new infra-generic classification. This study, based on available systematic data, circumscribes Eugenia in its current sense and provides detailed descriptions and illustration of the resulting nine infra-generic sections: Eugenia sects. Eugenia, Calycorectes, Hexachlamys, Phyllocalyx, Pilothecium, Pseudeugenia, Racemosae, Speciosae and the largest, Umbellatae that contains two thirds of the species in the genus. Relationships between Eugenia and Old World genera currently accepted as synonyms of Eugenia (Jossinia, Monimiastrum, Myrtopsis and Chloromyrtus) are also discussed. The paper presents a wide range of changes at the sectional level resulting in five new sectional synonyms, two new combinations, a lectotypification and one name of new status. An identification key to the sections is provided.

Myrtaceae is one of the richest families in the Atlantic Forest, a priority biodiversity hotspot that continues to be highly threatened, subject to rapid urbanisation and high levels of resource exploitation. Authors have suggested that individual lineages can be used as models to study biome evolution and ecology and to provide data for conservation planning in these areas. Here we review how Myrtaceae fit the 'model' criteria and examine the family's distribution throughout the Brazilian Atlantic Forest answering the questions: What is the ecological representation of Myrtaceae in the Atlantic Forest?; What is the current taxonomic situation of Myrtaceae in the biome?; What is the current phylogenetic understanding in the family?; Does the historical timeframe of the lineage coincide with that of the biome?; Can Myrtaceae be used to discuss species diversity hotspots within the Atlantic forests?; What is the role of Myrtaceae in conservation strategy? And finally, Can Myrtaceae be used as a 'model' taxon? The concept of the 'model taxon' is also discussed. The review concludes that taxonomic and phlyogenetic understanding in Myrtaceae are rapidly increasing, giving hope that taxonomic stability, easy species identification and management are realistic in a way unthinkable only a few decades ago. Myrtaceae function well as a 'model' within the Atlantic forest but fit some criteria better than others. Taxa can qualify as 'models' representing different times and pressures in the history of a given biome; each tells its own story. For future 'model' group studies to have maximum impact and implementation for evolutionary studies and conservation strategy, synthetic studies of multiple 'model' groups using multiple approaches

The shortage of reliable primary taxonomic data limits the description of biological taxa and the understanding of biodiversity patterns and processes, complicating biogeographical, ecological, and evolutionary studies. This deficit creates a significant taxonomic impediment to biodiversity research and conservation planning. The taxonomic impediment and the biodiversity crisis are widely recognized, highlighting the urgent need for reliable taxonomic data. Over the past decade, numerous countries worldwide have devoted considerable effort to Target 1 of the Global Strategy for Plant Conservation (GSPC), which called for the preparation of a working list of all known plant species by 2010 and an online world Flora by 2020. Brazil is a megadiverse country, home to more of the world's known plant species than any other country. Despite that, Flora Brasiliensis, concluded in 1906, was the last comprehensive treatment of the Brazilian flora. The lack of accurate estimates of the number of species of algae, fungi, and plants occurring in Brazil contributes to the prevailing taxonomic impediment and delays progress towards the GSPC targets. Over the past 12 years, a legion of taxonomists motivated to meet Target 1 of the GSPC, worked together to gather and integrate knowledge on the algal, plant, and fungal diversity of Brazil. Overall, a team of about 980 taxonomists joined efforts in a highly collaborative project that used cybertaxonomy to prepare an updated Flora of Brazil, showing the power of scientific collaboration to reach ambitious goals. This paper presents an overview of the Brazilian Flora 2020 and provides taxonomic and spatial updates on the algae, fungi, and plants found in one of the world's most biodiverse countries. We further identify collection gaps and summarize future goals that extend beyond 2020. Our results show that Brazil is home to 46,975 native species of algae, fungi, and plants, of which 19,669 are endemic to the country. The data compiled to date suggests that the Atlantic Rainforest might be the most diverse Brazilian domain for all plant groups except gymnosperms, which are most diverse in the Amazon. However, scientific knowledge of Brazilian diversity is still unequally distributed, with the Atlantic Rainforest and the Cerrado being the most intensively sampled and studied biomes in the country. In times of “scientific reductionism”, with botanical and mycological sciences suffering pervasive depreciation in recent decades, the first online Flora of Brazil 2020 significantly enhanced the quality and quantity of taxonomic data available for algae, fungi, and plants from Brazil. This project also made all the information freely available online, providing a firm foundation for future research and for the management, conservation, and sustainable use of the Brazilian funga and flora.

This study provides a robust phylogenetic framework to address important historical questions for Eugenia s.l. within an evolutionary context, supporting the need for better taxonomic study of one of the largest genera in the Neotropics. Furthermore, valuable insight is offered into diversification and biome shifts of plant species in the highly environmentally impacted Atlantic forest of South America. Evidence is presented that climate stability in the south-eastern Atlantic forest during the Quaternary contributed to the highest levels of plant diversity in this region that acted as a refugium.

The taxonomy of Myrteae, the most species-rich tribe of Myrtaceae, is notoriously difficult. Although the understanding of the phylogeny has improved, the morphological characteristics that support its cladistic configuration are still unknown. The present study evaluates stamen position and anthesis type as characters of systematic and evolutionary relevance. Sixty-nine species from 41 genera across the tribe were checked using herbarium material and spirit collections. The results recognize three patterns of stamen position in the pre-anthetic bud: straight, semi-curved and strongly incurved. The three patterns of stamen position correspond to the phylogenetic structure of the tribe, supporting the topology of the clades. Incurving of stamens across the evolutionary history of Myrteae appears to be linked to hypanthium extension and leads to different anthesis types that may be related to shifts in pollination strategy. The accessibility of stamen position and its systematic consistency make this character a useful tool for field and herbarium identification, and allow the inference of relationships for taxa not yet sampled in molecular analyses.