EUGENIA STENOCARPA (MYRTACEAE), A NEW SPECIES FROM THE ATLANTIC FOREST OF SÃO PAULO, BRAZIL, WITH A REMARKABLE FRUIT

The new species Eugenia stenocarpa Valdemarin & A.Maruy. is described and illustrated. It is nested within Eugenia sect. Speciosae but is distinguished from other species in the section by the combination of its sparsely puberulent and glabrescent young twigs, revolute leaf margin with a thickened yellow edge, flowers with pubescent hypanthium, and remarkable cylindrical fruits. Images of a specimen in situ and of dried material are provided, as is a provisional conservation assessment and discussion of morphological similarities between Eugenia stenocarpa and other Eugenia species.


Introduction
The family Myrtaceae Juss. is predominantly distributed in tropical and subtropical regions, with some gatherings in the Mediterranean (Biffin et al., 2010;Thornhill et al., 2015).It comprises 127 genera and c.6000 species (POWO, 2024).In the Brazilian Flora, Myrtaceae is one of the most speciose angiosperm families, with 29 genera and 1203 species, 796 of which are endemic to Brazil.Of these endemics, 77% occur in the Atlantic Forest (BFG, 2018(BFG, , 2021;;Proença et al., 2024).The Neotropical species of Myrtaceae are notable for their fleshy fruits, which are an important food source for animals (Gressler et al., 2006;Gomes et al., 2017).
Eugenia L. is represented by c.1100 tree and shrub species worldwide and is the most species-rich Neotropical genus of Myrtaceae.It is morphologically characterised by solitary flowers or inflorescences with up to two levels of branching, generally tetramerous flowers with free calyx lobes, stamens straight in the bud, ovary with two locules, seeds attached at a single point on the septum, and embryo with fused or partially fused cotyledons (Mazine et al., 2016(Mazine et al., , 2018a;;Lucas et al., 2019) (Mazine et al., 2014(Mazine et al., , 2018a;;Flickinger et al., 2020).
Eugenia is the largest genus in the Brazilian flora, comprising 414 species (Mazine et al., 2020), and is especially rich in the Atlantic Forest domain, where it plays an important ecological role (BFG, 2015;Lucas & Bünger, 2015;BFG, 2018;Oliveira-Filho & Fontes, 2000).Indeed, the Atlantic Forest has the highest number of Eugenia species among all Brazilian domains, with 262 species recorded thus far (Mazine et al., 2020), and several new species described from the southern region in recent years (Faria et al., 2015;Mazine et al., 2017;Proença et al., 2017;Mazine et al., 2018b;Sobral & Souza, 2018;Valdemarin et al., 2022).Here, we describe and illustrate a new species from the Atlantic Forest of the municipality of Cunha, São Paulo state, at the boundary with Rio de Janeiro state.

Materials and methods
Fieldwork was carried out between 2018 and 2023, covering all seasons, in the Atlantic Forest surrounding the Serra do Mar State Park (SMSP) in the states of São Paulo and Rio de Janeiro.Measurements were based on dried specimens from the following herbaria: ESA, RB, SORO, SP and SPSF (herbarium codes follow Thiers, continuously updated).Morphological terminology follows Hickey (1973) for leaf shape, Payne (1978) for hairs, Briggs & Johnson (1979) for inflorescences, and Harris & Harris (2001) for the remaining characters.Morphological characters of related species are determined from original descriptions and observations of specimens in the herbaria cited above.The size and density of the oil glands were determined from images under magnification, using the ImageJ2 software and following Rueden et al. (2017).
Habitat and ecology.This species grows on clay soils in dense ombrophilous forest above 1000 m a.s.l.(see Figure 3) with an average annual precipitation of 1421 mm.It was collected from riverine environments and tropical montane cloud forest with a history of degradation (Neves et al., 2017).Flowering in June through August; fruiting in August through September.
Etymology.The specific epithet refers to the species' narrowly cylindrical fruits, an unusual characteristic in Eugenia sect.Speciosae.
Proposed IUCN conservation category.This species has a restricted distribution and is known from only three closely situated localities within the SMSP and its buffer zone.The estimated EOO of 0.045 km 2 and AOO of 8 km 2 fall within the thresholds for the Critically Endangered (CE) category under criterion B. However, Eugenia stenocarpa occurs in a protected area, and the presence of a buffer zone suggests that it is not under any major threats or undergoing continuing decline.Therefore, the new species is classified at present as Least Concern (LC).

Figure 3 .
Figure 3. Distribution of Eugenia stenocarpa in the Atlantic Forest of São Paulo, Brazil.
. Morphological variation can be observed in the fusion of calyx lobes, particularly among species of Eugenia sect.Pseudeugenia Mazine & Faria, Eugenia sect.Schizocalomyrtus (Kausel) Mattos and Eugenia sect.Umbellatae O.Berg.The number of calyx lobes in the genus is usually four but varies from four to six in Eugenia sect.Hexachlamys (O.Berg) Mazine.A higher number of branching in inflorescences (e.g.thyrse) can be observed in Eugenia sect.Pilothecium (Kiaersk.)D.Legrand.Molecular studies support the monophyly of Eugenia, and 11 sections are currently recognised .4a.Leaf blades with a thickened and yellow edge, pedicel not swollen at the apex

Table .
Morphological features of Eugenia stenocarpa Valdemarin & A.Maruy., sp.nov., and related species in the Atlantic Forest of Southeast Brazil.