Plinia renatiana G.M. Barroso & Peixoto (1991: 98)

Fonseca, Heitor Lisboa Da, Tuler, Amélia Carlos, Rosa, Patricia Da, Freitas, Joelcio & Lírio, Elton John De, 2024, Redescription and reevaluation of the extinction risk of Plinia renatiana (Myrtaceae), a species endemic to the state of Espírito Santo, Brazil, Phytotaxa 641 (3), pp. 191-209 : 193-198

Plinia renatiana G.M. Barroso & Peixoto (1991: 98) .

Type:— BRAZIL. Espírito Santo: Linhares, Reserva Natural da CVRD ; Estrada 163, Km 1,07. Próximo a uma Jataipeba , um Imbaubão , ao lado do aceiro com Silvestre Milanez [CVRD Natural Reserve; Road 163, Km 1.07. Near a Jataipeba tree, an Imbaubão tree, next to the firebreak with Silvestre Milanez], 25 october 1979 (fl.) I. A. Silva 104 (holotype CVRD!, isotype RBR!, isotype RB!) .

Tree, up to 14 m in height, cylindrical trunk approximately 3 m in length, rough bark with flaking in plates, darker internally than externally, diameter at breast height 14–15 cm, crown diameter 3– 7 m. Branches terete, internodes 2.4– 4. 9 cm, with opposite distichous phyllotaxy. Petioles dark brown in mature fresh leaves, light green in young leaves, 0.9–1.7 cm in length, deeply channeled adaxially. Blades oblong, coriaceous, apex acute-acuminate, base cuneate or attenuate, narrowed and decurrent over the petioles, 6.6–23.6 x 2.5–8.9 cm, glabrous, discolorous, adaxial surface leafgreen, abaxial surface light green (fresh leaves), margin entire and revolute, penninerved and brochidodromous, with marginal vein 0.3–0.4 cm from the margin, 23–35 pairs of inconspicuous lateral veins on both surfaces, midvein flat adaxially and prominent abaxially, with conspicuous glandular dots visible through the light. Inflorescences axillary in metabotrioid racemes, 1–8 cm in length, with 9–33 flowers, arranged in triads, featuring bracts at the insertion of the main axis and at the base of each triad, along with bracteoles at the base of each floral bud. Bracts 1.45–2.40 mm, and bracteoles 0.64–1.74 mm, triangular, pilose, with attenuate tectors trichomes. Buds glabrous, infundibuliform, white or yellowish, approximately 6 x 5 mm, with splitting of the 4 calycinal lobes at the apex, alternate prefloration. Flowers actinomorphic, tetramerous, epigynous, the elongated hypanthium forming a circular and flattened receptacle with approximately 5.3 mm in diameter, calycinal lobes 4, triangular, acute and erect, approximately 3.1 mm in length, petals white, pilose with attenuate trichomes, developed, ovate, approximately 4.3 mm in length, with visible veins, androecium with staminophore with 3 to 4 staminal rings, stamens (24–)106–146, approximately 7.7 mm in length, curved in the bud, filaments filiform, anthers basifixed, bithecous, with rimose dehiscence, pistil with bicarpellate ovary and sycarpous pistils, elongated and filiform stylus, with approximately 6.1 mm in length, stigma simple, ovary with walls fused to the hypanthium, bilocular, with two ovules with basilar placentation per locule. Fruit globose, approximately 3.0 x 2.5 cm, berry, light green when unripe, yellow with dark spots when ripe, deeply longitudinally grooved from base to apex, grooves approximately 1 mm deep, warty, with prominent and elongated base and apex, persistent calyx, pericarp slightly thick, 1–2 seeds per fruit. Seed spherical, approximately 1.5 x 1.5 cm. Eugenioid embryo, with two plan-convex amyloid cotyledons completely separated.

The species exhibits vegetative characteristics similar to Plinia marqueteana G.M. Barroso (1994: 2) , but it can be distinguished by the inflorescence in fascicles in the second, and the fruits, which have a smooth skin (vs. grooved in P. renatiana ) and are darker when ripe (vs. yellow in P. renatiana ). The inflorescences resemble those of Plinia silvestris ( Vellozo (1829: 215)) Mazine & Sobral et al. (in Sobral et al. 2017: 88) and Plinia pseudodichasiantha (Kiaerskou (1893: 177)) G.M.Barroso ex Sobral (2008: 107), but it differs from them by developing in leaf axils, not on branches. It also bears some similarities to Plinia rivularis (Cambessèdes (1829: 377)) Rotman (1985: 195), but it can be distinguished from it by leaf morphology, which is lanceolate (vs. oblong in P. renatiana ). Additionally, it shares characteristics with several species of Myrcia DC (Drapiez, P.A.J. 1822-1831: 406), such as leaf shape and type of inflorescences. Some of these aforementioned characteristics are highlighted in Figure 1 . In Figure 2 , important structures are represented, such as flowers, inflorescence, and stamens, highlighting significant morphological characteristics, including the number, arrangement, and size of stamens in the flower, as well as the arrangement of flowers in the inflorescence.

Specimens examined: — BRAZIL. Espírito Santo: Linhares, Reserva Natural da CVRD ; Est. Jacaranda, Ant. 232, km 3.036, lado esquerdo. 27 January 1984 (fr.) D. A. Folli 495 (paratype) (RB!, CVRD!, ICN!, RBR!, SPF!) ; Linhares , Reserva Natural da CVRD ; Estrada Orelha de Onça, Km 1,4. Tabuleiro , 08 August 1986 (fl.) D. A. Folli 595 (RB!) ; Linhares , Reserva Natural da CVRD ; BR-101, Aceiro Jueirana , km 0,1, 6 November 2003 (fl.) D. A. Folli 4664 (CVRD!, SPF!) ; Linhares , Reserva Natural da CVRD ; Estrada Municipal Canto Grande , km 0,35, 17 March 2004 (fr.) D. A. Folli 4775 (CVRD!, SPF!) ; Linhares, Reserva Natural Vale , 08 February 2008 (st.) D. A. Folli 5923 (CVRD!) ; Linhares , Reserva Natural da CVRD ; Est. Farinha Seca , km 4.110, lado esquerdo, 23 November 1989 (fr.) G. L. Farias 342 (RB!) ; Linhares , Reserva Natural da CVRD ; A 50m da torre, lado esquerdo. Floresta alta, 15 February 1991 (fr.) G.L. Farias 409 (CVRD!, SPF!, BHCB!) ; Linhares , Reserva Natural da CVRD ; Estrada Flamengo, km 0,8 - trilha do Pequi amarelo, 08 August 2006 (st.) M. C. Souza 353 (RB!) ; Linhares, Reserva Natural da CVRD, Estrada Orelha de Onça , Km 1,4, Tabuleiro , 02 April 2008 (st.) M. C. Souza 650 (RB!) ; Linhares , Reserva Natural da CVRD ; Próximo a parada 5 da trilhas, 03 March 2020 (fr.) G. S. Siqueira 1345 (CVRD!, RB!, SPF!) ; Linhares , Reserva Natural da CVRD ; Margem do aceiro Aracruz, Santa Terezinha , 30 March 2012 (fr.) J. E. Q. Faria 2502 (HUFSJ, UB, HUEG, CVRD!, SPF!) ; Linhares, Próximo a uma Angélica , 20 November 1972 (fl.) J. Spada 76 (CVRD!, SPF!) ; Santa Teresa, Alto Santo Antônio, sitio do Boza , 27 November 2006 (fl.) E. J. Lucas 724 (ESA!) ; Linhares , 13 December 2006 Valdemarin 456 (ESA) ; Santa Teresa, Parque Natural Municipal de São Lourenço ; Entre a área 2 e 3, 27 December (fr.) 2003 T. A. Cruz 112 (MBML!) ; Santa Teresa, Estação Biológica de Santa Lúcia ; Área 3, parcela 28, Número 791, 27 April 1993 (st.) L. D. Thomaz 1498 (MBML!) ; Santa Teresa, Estação Biológica de Santa Lúcia ; Área 2, Parcela 62, Número 1503, 30 June 1993 (st.) L. D. Thomaz 1499 (MBML!) ; Domingos Martins, Rod. BR-262, Rio Jucu Braço Sul , próximo a Vítor Hugo , 20 October 1994 (fl.) Hatshcbach 61191 (SPF!, NYBG!, ESA!, UPCB!, CEPLAC!, ASU!, SP!, IF!, MO) ; Bahia: Ilhéus, Área do CEPEC. Entrada trilha em frente ao herbário, perto do ponto de ônibus, 08 March 2018 Stadnik 606 (ALCB!) ; FRENCH GUIANA. Cayenne, Mont Atachi Bacca- Region de L’Inini. Nord du plateau sommital, 10km SE de Gobaya Soula. Cayenne, French Guiana , 19 January 1989 (fr.) de Granville 10773 (ASU!) ; Cayenne, Piste de Saint Elie , 28 March 1984 (fr.) D. Sabatier 828 (ASU!)

Six individuals (#127, 791, 1503, 2119, 2521 and 2660) identified as P. renatiana were sampled in a phytosociology study at EBSL in Santa Teresa, ES ( Thomaz & Monteiro 1997, Saiter 2011, Saiter & Thomaz 2014). During an expedition in 2022, it was observed that one of the individuals (#1503) was dead. The remaining five living individuals were all sterile, and there are doubts as to their identity, except for individual #2660, which we do not consider to be P. renatiana , as it differs significantly in leaf morphology due to its obovate shape and rounded apex, with a length of approximately 5 cm (vs. ca. 16 cm in P. renatiana ). During an expedition in RNV, we found nine individuals of the species, all of which were sterile, including two mature individuals and seven juveniles. In total, 32 records of P. renatiana were identified, including data collected in the field and records in herbaria. However, seven of these records have incorrect determinations (marked with * in S1), meaning that they do not correspond to P. renatiana , but to other Myrtaceae species with similar morphological characteristics. This resulted in 25 individuals of P. renatiana stricto sensu being found in nature, with seven of them being new field records within the scope of this work.

Phenology

The reproductive phenology ( Figure 3 ) based on herbarium samples, demonstrates that the species has a reproductive period from October to March. The buds start to appear between October and November, and the anthesis occurs successively between October and December. Fruiting was observed from November to March, ripping in the last month. The data indicate that flowering and fruiting can occur simultaneously at certain times.

Conservation status

Plinia renatiana has an Extent of Occurrence (EOO) of 2,161.43 km ² and an Area of Occupancy (AOO) of 60 km ², with four fragmented subpopulations. It is categorized as ‘Endangered’ (EN) due to multiple threats, including urban expansion, factories, tourism, agriculture, roads and highways, fires, habitat degradation, drought, extreme precipitation, and changes in the reproductive cycle caused by climate change. The primary threat is habitat degradation due to deforestation of the Atlantic Forest for various purposes. This forest has already lost more than 75% of its original coverage in the state of Espírito Santo ( Souza et al., 2020), and there are no signs of this trend stopping. Three conservation actions have been identified: maintaining protected areas, raising awareness and communication with the local population, and legal protection at the national level. There are no records of human use, either commercially or non-commercially, of this tree species. Four subpopulations of the species have been identified, which exhibit a disjunct and fragmented distribution ( Figure 4 ), located in: 1) the EBSL and 2) São Lourenço Municipal Natural Park, both in the municipality of Santa Teresa, 3) the municipality of Domingos Martins, along the BR-262 highway, and 4) the municipality of Linhares at the RNV.

The EBSL is managed by the National Atlantic Forest Institute, which conducts research in the fields of botany, zoology, and ecology. The São Lourenço Municipal Natural Park is administered by the municipal government. In recent years, the Pedra Azul State Park in the municipality of Domingos Martins has emerged as one of the main tourist destinations in the state, attracting visitors from all over Brazil and abroad. Associated with tourism, numerous real estate developments, restaurants, and agrotourism routes have emerged, leading to uncontrolled growth in the vicinity of the conservation unit. Consequently, deforestation of the Atlantic Forest in the region has occurred ( Narciso 2020). The Vale Natural Reserve (RNV), located in Linhares, is one of the largest protected areas of the Atlantic Forest in the state of Espírito Santo. However, Magnago et al. (2016) demonstrated that even in large forest fragments like the RNV, the edge effect can alter functional diversity, favoring pioneer species and early secondary species with independent dispersion, which can lead to changes in interactions between animals and plants. As a result, the pollination and seed dispersion process may be hampered, directly influencing population dynamics.

Thomaz & Monteiro (1997) identified five individuals of P. renatiana in 1.02 hectares of Dense Ombrophilous Forest at the EBSL in Santa Teresa, ES. The study conducted by Saiter & Thomaz (2014) confirmed that this species still exists in the same locations that were analyzed in 1997. This indicates that it is a rare species with low-density populations. The species was recorded outside of conservation units. Therefore, there is an inference of a continuous decline in the number of mature individuals due to the decline in habitat quality and extent, as well as genetic isolation among subpopulations. These factors can also lead to a decrease in the area of occupancy. Consequently, the species is categorized here as “Endangered” (EN) (criteria A2c; B1+2ab(i,ii,iii,v)), without a change in category but a shift in the criteria used in the assessment conducted by Martinelli & Moraes (2013) (A2c; B1ab(iii,v); C1+2a(i)).

Figures

FIGURE 1. Plinia renatiana. A) Mature individual in the Vale Natural Reserve, Linhares, ES; B) Inner bark darker than outer bark; C) Branch and leaves on the adaxial surface; D) Branch and leaves on the abaxial surface; E) Inflorescence (Folli, D.A. 4664); F) Floral bud; G) Overall appearance of the flower; H) Flower with hypanthium, calyx, and stigma in focus; I) Flower with corolla in focus; J) Petal; K) Hypanthium in sagittal section highlighting the ovary; L) Ripe fruits. (Photos A-K: H. L. Fonseca; Photo L: G. Siqueira).

FIGURE 2. Plinia renatiana. A) Branch with fruit; B) Leaf showing the prominent veins; C) Inflorescence with flowers and buds; D) Preanthesis bud; E) Flower; F) Flower - stamens and corolla removed, highlighting the stigma, calyx, and hypanthium; G) Petal; H) Stamen; I) Fruit. Illustration by J. Freitas.

FIGURE 3. Reproductive phenology of Plinia renatiana based on herbarium samples.

FIGURE 4. Geographic distribution of Plinia renatiana G.M.Barroso & Peixoto.