Matheus Fortes Santos

Myrcia is the sole genus within the subtribe Myrciinae (tribe Myrteae, family Myrtaceae) and includes approximately 800 species, divided into nine sections. One of these sections, Myrcia sect. Eugeniopsis, is the focus of the present study. This section is characterized by several distinctive features, including: reddish trichomes; young branches, leaves and flowers covered by numerous gland dots; inflorescence usually arising at the subterminal nodes of the branch of the season, with an early deciduous bract; clavate floral bud with the corolla barely visible before anthesis; hypanthium extending into a tube beyond the ovary, not tearing at anthesis or often with a small vertical rip (but usually not tearing the staminal ring); calyx lobes small, free and deciduous parallel to the hypanthium ring; and staminal ring thin and usually with trichomes. Another typical feature is the discolorous leaf blade in the dried specimens, where the adaxial surface is darkened and the abaxial surface is lighter. The species within this section are endemic to the eastern portion of South America, primarily concentrated in the Atlantic Forest Domain. Collections of 36 herbaria were analysed, totalling about 1,200 specimens, with at least one type material for each name checked in loco. Field expeditions were conducted, and some species were also studied in their natural habitats. The characterization of the section is provided, as well as an identification key. The taxonomic treatment for each species includes nomenclatural data, comprehensive morphological descriptions, and discussions on distribution, habitat, phenology and taxonomy. Distribution maps, conservation status and images of representative specimens for each species are also provided. Sixteen species are currently accepted in Myrcia sect. Eugeniopsis: Myrcia advena, Myrcia clausseniana, M. eugenioides, M. eugeniopsoides, M. ferruginosa, M. gaudichaudiana, M. hatschbachii, M. maculata, M. oblongata, M. polygama, M. reitzii, M. suberosa, M. tenondeporan, M. tenuivenosa, M. teuscheriana and M. vellozoi.

The taxonomy of Neotropical Myrtaceae is known for the difficulties regarding specific and supraspecific taxonomic delimitations. In subtribe Myrciinae (tribe Myrteae) this situation is intensified due to the high diversity of species and relatively homogeneous morphology. Over the last two decades there has been a huge increase in Myrciinae systematic research. Following use of molecular phylogenetic works, several genera accepted in the 20th century were synonymised under a broader circumscription of Myrcia. Monophyletic sections that facilitated further taxonomic works were recognised. However, species with doubtful morphologies, scanty or missing data have remained untreated. This paper provides an update of the taxonomic status of these species as well as a list of accepted species of Myrciinae, assigned to sections of Myrcia. This work is based on a broad analysis of herbarium collections including types and the Myrciinae literature. Taxonomic comments are provided regarding species placement and features, and three new combinations, one new name, nine lectotypifications and two neotypifications are provided. Seven species are transferred to other genera or families. Thirty-seven species are listed as incompletely known due to absence of type specimens or any material that could clarify their taxonomic status. We currently accept 744 species of Myrcia (excluding the 37 species without known type collections and three species with uncertain generic placement), distributed between taxonomic sections as follows: Myrcia sect. Aguava (32 species), Myrcia sect. Aulomyrcia (162 species), Myrcia sect. Calyptranthes (248 species), Myrcia sect. Eugeniopsis (18 species), Myrcia sect. Gomidesia (67 species), Myrcia sect. Myrcia (158 species), Myrcia sect. Reticulosae (15 species), Myrcia sect. Sympodiomyrcia (28 species), Myrcia sect. Tomentosae (5 species), and clade 10 with nine species. Three species remain in Myrcia but are probably members of other taxa of Myrteae (M. cionei, M. skortzoviana) or other family (M. melastomoides), while two species of Myrcia (M. apiocarpa, M. sintenisiana) remain without a sectional placement. We highlight taxonomic issues to address in the future to improve systematic knowledge in Myrciinae.

Premise: Increasingly complete phylogenies underpin studies in systematics, ecology, and evolution. Myrteae (Myrtaceae), with ~2700 species, is a key component of the exceptionally diverse Neotropical flora, but given its complicated taxonomy, automated assembling of molecular supermatrices from public databases often lead to unreliable topologies due to poor species identification.Methods: Here, we build a taxonomically verified molecular supermatrix of Neotropical Myrteae by assembling 3909 published and 1004 unpublished sequences from two nuclear and seven plastid molecular markers. We infer a time‐calibrated phylogenetic tree that covers 712 species of Myrteae (~28% of the total diversity in the clade) and evaluate geographic and taxonomic gaps in sampling.Results: The tree inferred from the fully concatenated matrix mostly reflects the topology of the plastid data set and there is a moderate to strong incongruence between trees inferred from nuclear and plastid partitions. Large, species‐rich genera are still the poorest sampled within the group. Eastern South America is the best‐represented area in proportion to its species diversity, while Western Amazon, Mesoamerica, and the Caribbean are the least represented.Conclusions: We provide a time‐calibrated tree that can be more reliably used to address finer‐scale eco‐evolutionary questions that involve this group in the Neotropics. Gaps to be filled by future studies include improving representation of taxa and areas that remain poorly sampled, investigating causes of conflict between nuclear and plastid partitions, and the role of hybridization and incomplete lineage sorting in relationships that are poorly supported.

Myrcia sect. Eugeniopsis is one of the nine sections of Myrcia (Myrciinae, Myrteae, Myrtaceae) and includes mostly species of the current synonym genus Eugeniopsis. Using fieldwork and the analysis of herbarium collections as a basis, we describe here a new species of this section, Myrcia tenondeporan, which is endemic to the Atlantic Forest in the Serra do Mar Mountains. The new species is related to Myrcia vellozoi and Myrcia multipunctata but differs mainly in the leaf shape and size, inflorescence structure and size of floral buds.

Myrcia DC. sect. Calyptranthes (Sw.) A. R. Lourenço & E. Lucas is a section of the Neotropical genus Myrcia with ca. 260 known species. This paper provides a taxonomic revision of 89 species occurring across South and Central America, including the Amazon, Andes, Guiana Shield, and Mesoamerica, and extending into the Caribbean archipelago, but not including those previously treated from the Atlantic Forest of Brazil. The treatment includes an identification key, informal taxonomic groupings and notes, geographic distribution information, and extinction risk assessments. Figures illustrating key morphological characters of the genus are provided including common leaf, flower bud, and inflorescence arrangements. Ten new synonyms, eight new lectotypes, and four new combinations are proposed, and a key to treated species is supplied.

Myrcia amplifolia, a new species from the coastal forest of southern Bahia, eastern Brazil, is here described and compared with morphologically similar species. Additionally, a morphological plate, distribution map and conservation assessment of the species are presented. We assign the new species to Myrcia sect. Calyptranthes with a reasonable reliability due to the combination: presence of cataphylls, inflorescences sympodially branching at the base and calyptrate flowers. Myrcia amplifolia seems to be closely related to M. carioca, from which it can be distinguished through the leaf blades strongly coriaceous (vs. chartaceous in M. carioca), leaf venation very slightly raised and barely conspicuous abaxially (vs. venation strongly raised and conspicuous abaxially), inflorescences with a shorter main axis (75–110 mm long vs. 130–270 mm long), and shorter first lateral branch (3.3–19 mm long vs. 48–95 mm long), and the calyptra acuminate (vs. rounded or shortly apiculate). It is also similar to M. boanova, differing by the leaf blades significantly larger (31–60 × 10–20 cm vs. 7–13 × 4.1–5 cm in M. boanova) and strongly coriaceous (vs. chartaceous), and the calyptra acuminate (vs. rounded) and smaller (2.3–2.6 × ca. 1.8 mm vs. 3.5–3.7 × 3.5–4 mm).

A new species, Myrcia suberosa, is here proposed based in an ongoing taxonomic revision of Myrcia sect. Eugeniopsis, a group nearly endemic to the Atlantic Forest. Myrcia suberosa occurs in Brazil from Southern Bahia to Southern Rio de Janeiro states, but only three collections are known and the real distribution of the species is barely known. The new species is morphologically related to Myrcia pseudomarlierea and Myrcia teuscheriana, differing by sexual system, cork thickness, indument, and leaf and flower morphologies. Morphological description, images and conservation status are provided, as well as discussion about distribution, habitat, phenology and taxonomy.

Recent phylogenetic and taxonomic studies resulted in the synonymization of Marlierea into Myrcia. This paper aims to transfer the last Marlierea species to their correct genera, which include not only taxa belonging to Myrcia, but also to Eugenia, Plinia and Siphoneugena. Five new combinations are proposed: Eugenia choriophylla, based on Marlierea choriophylla; Myrcia resupinata, based on Myrtus resupinata; Plinia parvifolia, based on Marlierea parvifolia; Plinia sessiliflora, based on Marlierea sessiliflora; and Siphoneugena martinellii, based on Marlierea martinellii. Two new names are proposed: Myrcia rufopilosa, replacing Myrtus rufa; and Myrcia sintenisiana, replacing Marlierea sintenisii. A new synonym is proposed, Marlierea cordata under Eugenia hirta. Three names, Marlierea capitata, Marlierea involucrata and Marlierea occhionii remain as incertae saedis, and, additionally, we have listed two nomina nuda referenced in the literature as Marlierea.