João Marcelo Alvarenga Braga’s research while affiliated with Instituto de Pesquisas Jardim Botânico do Rio de Janeiro and other places

In this paper, we present comprehensive data on two endemic and threatened species of Myrcia (Myrtaceae) from the Brazilian Atlantic Forest. Both belong to Myrcia sect. Aulomyrcia and were previously known only from a few collections made in the state of Rio de Janeiro. Apart from the type specimens and our recent collections, each species has been recollected on only three occasions. Considering the last collections of each species, Myrcia colpodes was rediscovered by our team after a collection gap of 64 years, while M. rubiginosa was found after 16 years. Myrcia colpodes can be recognized by vinaceous, exfoliating bark on the trunk, strongly bullate leaves and relatively long, glabrous panicles. Myrcia rubiginosa is characterized by fissured, greyish-brown bark on the trunk, conspicuous brownish and tomentose indumentum on young leaves and inflorescences, and pendular panicles with relatively small flowers. Data provided here include updated morphological descriptions for the taxa, along with notes on their morphological affinities and geographic distribution. Their fruits are here described and illustrated for the first time.

Global changes can impact ecosystem resilience, leading to abrupt and irreversible shifts in structure and function. In the face of increasing anthropogenic disturbances, understanding mechanisms that destabilize ecosystems and push them into alternative stable states is crucial. We conducted a systematic review of the application of concepts from dynamic systems theory—alternative stable states, tipping points, hysteresis, and alternative pathways—in tropical terrestrial ecosystem research. We identified 135 articles (71 observational, 59 theoretical/modeling, four experimental, one meta‐analysis) using these concepts, addressing ecosystem changes due to anthropogenic and natural disturbances. Most articles focused on conservation biology (46%), followed by climate change (31%), successional ecology (28%), ecological restoration (16%), physiology (15%), novel ecosystems (3%), and biological invasion (3%). Fire was the primary disturbance driving shifts into alternative stable states (54%). Disturbance roles varied across biomes. Numerous articles on tropical and subtropical broadleaf forests highlighted biodiversity and ecosystem service losses due to disturbances. Conversely, studies on tropical and subtropical grasslands, savannas, and shrublands emphasized fires and herbivory as key factors in the maintenance of the structure and composition of savannas. The high number of articles on these biomes underscores their importance. The review highlights that considering alternative stable states in the responses of ecosystems to global changes can enhance disturbance mitigation and ecological restoration, potentially averting future biodiversity and ecosystem service losses. Addressing ecosystem responses to global changes from this perspective can enable more effective disturbance mitigation and ecological restoration actions.

This paper documents the rediscovery of Eugenia grandifolia, an endemic species from the Brazilian state of Rio de Janeiro that was primarily known from 19 th century collections. Eugenia grandifolia is remarkable by its relatively large, subsessile leaves with cordate bases, inflorescences in racemes and often ramiflorous, and fruits with up to seven seeds. We provide herein a second step lectotypification, updated morphological description, notes on taxonomy, distribution, habitat, and phenology of the species. The presence of colleters in the species is first recorded here. Its fruits, previously unknown to science, are illustrated and described herein, and the first photographic documentation of the live plant in its habitat is also presented. Finally, we present a distribution map and a reassessment of the conservation status of E. grandifolia.

We describe two new species of Marantaceae of the Brazilian Atlantic Forest. These species were discovered in northern Espírito Santo state, inside Reserva Natural Vale. Ctenanthe brevibractea is here compared to C. lanceolata, and can be distinguished by its overall shorter stature, glabrous leaf sheath, inflorescence rachis with shorter internodes, component bracts obovate-acuminate, deciduous, holding 1–2 cymules, per cymule with one bracteole, and flowers with solitary, spathulate outer staminodes. Saranthe rufopilosa is most similar to S. leptostachya, but differs by having 2-nodated inflorescences, and indumentum of long stiff reddish trichomes disposed on peduncles, rachis, internodes of inflorescences, cymule peduncles, pedicels, sepals and ovary. Their distribution maps and photographs are also provided.

During the development of the taxonomic treatment of Ernestia we came across a taxonomic novelty and a species for which taxonomic verification was needed from Colombia. Herein, we propose Ernestia rheophytica a new species belonging to the sensu stricto clade of the genus, and clarify the identity of Acisanthera goudotii, now treated as E. goudotii. We also clarify the status of the original material of E. goudotii and propose the lectotypification of E. ovata and its synonymization under E. goudotii. Ernestia rheophytica, as the name indicates, is a rheophytic species, a rare habit in Melastomataceae, especially in Marcetieae.

This study was initially driven by efforts to identify a species of Campomanesia from the Brazilian Atlantic Forest that was introduced into cultivation because of it excellent fruits, using seeds collected in 2007. Tentatively interpreted as a new taxon, after examination of the types of synonyms of its apparent close relatives, we found that this taxon corresponds closely to the type and original description of Abbevillea langsdorffii, which is currently considered a synonym of Campomanesia sessiliflora var. sessiliflora. Examination of original descriptions, types, historical and modern herbarium collections and cultivated individuals support the recognition of A. langsdorffii as a distinct species. The existence of C. langsdorffii prevents using this combination, and, therefore, we propose Campomanesia lorenziana as a necessary replacement name. We provide herein an updated morphological description for C. lor-enziana, including a report on fruit taste, morphological photographs and drawings and a taxonomic discussion. Campomanesia lorenziana is similar to C. hirsuta and C. phaea, so we provide morphological data to distinguish them and a brief historical overview regarding the cultivation of C. lorenziana is also presented.

This study was conducted in the context of a taxonomic treatment for Myrcia species occurring in the Brazilian state of Rio de Janeiro. While revising current synonyms of endemic species of Myrcia sect. Gomidesia, we found consistent morphological separation between Myrcia gestasiana and Myrcia dolichopetala, presently treated as synonyms and detached here. Individuals co‐occurring with M. dolichopetala are here recognized and described as a new species, Myrcia macrobracteosa, the specific epithet being allusive of its unusually showy, persistent and accrescent bracts and bracteoles. A taxonomic treatment is provided for each species based on herbarium collections and field data, and their diagnostic characters are contrasted in a comparative table. Morphological plates of fresh and dry material are also provided with notes on taxonomy and distribution, including a map of occurrence records. The three taxa occur in urban forest remnants under extreme threat in the Rio de Janeiro Metropolitan Region. In this context, preliminary conservation assessments are also provided for each species based on occurrence data from herbaria and field information.

A new and critically endangered species of Phyllanthus, endemic to the Parque Nacional da Tijuca in Rio de Janeiro State, Brazil, is described and illustrated here. Phyllanthus celatus is placed in Phyllanthus subgenus Phyllanthus section Phyllanthus subsection Phyllanthus. Morphologically it resembles P. augustinii, P. lobatus and P. niruri, but differs mainly by presenting reddish primary, secondary and intersecondary veins on the abaxial surface (vs absent in both species), and 5-lobed pistillate disc (vs entire only in P. augustinii and P. niruri). Of these, only P. lobatus has a lobed disc, but it differs in pistillate sepals light green (vs whitish or slightly pinkish), deeply 5-lobed pistillate glandular disc (vs 3–5-lobed), styles erect (vs curved), and geographic distribution restricted to the Southeast (vs South). The systematic position of this species and its morphological relationships with allies are discussed and field photographs, illustrations, a distribution map, preliminary conservation status, and taxonomic notes are provided.