Eugenia stenocarpa Valdemarin & A.Maruy., 2024

Valdemarin, Karinne, S. C. Maruyama, Adriano, G. de Lima, Alexandre, C. Souza, Vinicius & F. Mazine, Fiorella, 2024, EUGENIA STENOCARPA (MYRTACEAE), A NEW SPECIES FROM THE ATLANTIC FOREST OF SÃO PAULO, BRAZIL, WITH A REMARKABLE FRUIT, Edinburgh Journal of Botany 81 (1945), pp. 1-12 : 2-8

Eugenia stenocarpa Valdemarin & A.Maruy. , sp. nov.

Eugenia stenocarpa is morphologically distinguished from all other species of Eugenia sect. Speciosae Bünger & Mazine by its cylindrical (vs globose) fruits. Additionally, it can be distinguished from the most similar species, Eugenia speciosa Cambess. , by its leaf blades with inconspicuous oil glands above and slightly raised below (vs raised on both surfaces in E. speciosa ), pedicels 25–39 mm long (vs 5–24 mm long), flowers with calyx lobes 4–5 mm long (vs 5–8 mm long) and pubescent hypanthium (vs glabrous).

– Type: Brazil, São Paulo, municipality of Cunha, Zona de amortecimento do PESM, Núcleo Cunha , Sítio Vivenda das Meninas, próximo à Estrada do Paraibuna , 23°13′45′′S, 45°00′50′′W, 1102 m, 2 viii 2020 [fl. and imm. fr.], K.S. Valdemarin, A. Maruyama & A. Gibau 1496 (holotype SORO, isotype ESA). Figures 1 , 2 .

Tree 3–5 m tall. Twigs slightly applanate when young, terete when mature, the distal internodes 15–55 mm long, 1–2 mm in diameter, longitudinally striate exfoliating in membranaceous irregular sheets, sparsely puberulent when young, trichomes whitish, glabrescent. Young leaves sparsely puberulent above, strigose below, trichomes adpressed and brownish. Leaves opposite, petiole (4)7–12 × 0.8–1.1 mm, terete, sparsely puberulent, trichomes glabrescent; blade (2.9)8–10 × 2.9–4.1 cm, elliptic or narrowly obovate, chartaceous, markedly discolorous when dry, upper surface dark green, sparsely puberulent or glabrous, lower surface olive green, sparsely strigose, base acute, attenuate or cuneate, apex obtuse or short-acuminate, sometimes rounded, sometimes falcate when dry, midvein sulcate in the proximal region becoming prominent on the upper third of the blade above, prominent below, sparsely puberulent above and strigose below, secondary veins (8)12–15 pairs, leaving the midvein at angles of 64–70°, slightly raised above and raised below, sparsely puberulent above and puberulent below, marginal veins 2, innermost 1–4 mm from the margin, outermost up to 1 mm from margin. Margin revolute with a thickened and yellow edge, and oil glands 0.1–1.5 mm in diameter, 5–10 per mm 2, inconspicuous above and slightly raised below. Inflorescences terminal or axillary auxotelic racemes with late vegetative proliferation and 1 or 2 pairs of flowers; rachis up to 12 mm long, terete, puberulent, glabrescent; bracts 2–3 × 0.5–0.8 mm, lanceolate or oblong, tomentose, glabrescent, persistent until fruiting, sometimes deciduous in the flowers; pedicels 25–39 × c. 0.7 mm, terete, puberulent; bracteoles 1.5–2.1 × c. 0.5 mm, narrow-lanceolate or linear, free, apex acute, puberulent, deciduous in bud, flower and mature fruit, trichomes whitish or brownish. Flower buds c.6 × 4 mm, obovate. Flowers with smooth, pubescent hypanthium; calyx lobes

4, fused by 1 mm at the base in bud, in two unequal pairs, the outermost 4–5 × 2.5–3.8 mm, ovate, apices acute, the innermost 4–4.5 × 3–3.5 mm, ovate, sparsely puberulent on both surfaces, oil glands prominent; petals 4, c.8 × 4.5 mm, obovate, glabrous and ciliate; staminal ring c. 3 mm in diameter, rounded, glabrous; stamens straight in the bud, filaments 4–7 mm long, glabrous, anthers 0.5–0.8 × 0.5 mm, oblong or globose, dehiscing longitudinally; style c. 5.5 mm, glabrous, stigma punctiform and papilose, ovary 2-locular, ovules 12–14 per locule, locule glabrous inside. Fruits 8–10.3 × 3.5–5.9 mm, cylindrical, smooth, glabrous. Seeds 1 per fruit, c.1.8 × 1.2 mm, globose; testa smooth; cotyledons fused with no visible hypocotyl. Distribution. Eugenia stenocarpa is found only in the Serra do Mar mountain range, in northeastern São Paulo state, at the boundary with Rio de Janeiro state. The new species was recorded in three localities in the municipality of Cunha. Two of them come from a private property (Sítio vivenda das meninas) located in the SMSP’s buffer zone in Paraibuna road, and the third from the waterfall trail within the SMSP area ( Figure 3 ).

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).

Notes. Based on morphology, the new species is assigned to Eugenia sect. Speciosae due to its auxotelic raceme inflorescences with late vegetative proliferation, foliaceous calyx lobes 4–5 mm long, and narrowly lanceolate to linear bracteoles that are sometimes deciduous in the bud or in flower but always in the mature fruits ( Bünger et al., 2016).

Currently, 10 species are nested in Eugenia sect. Speciosae ( Bünger et al., 2016; Mazine et al., 2020). Two occur in the Amazon region ( Eugenia tovomita Sobral & M.A.D.Souza and E. wentii Amshoff , neither restricted to Brazil), one in dry areas of the Brazilian Cerrado

( E. macedoi Mattos & D.Legrand ), and seven recorded from Brazilian Atlantic Forest

( E. anthropophaga Costa-Lima & E.C.O.Chagas , E. bunchosiifolia Nied. , E. hermesiana Mattos , E. jussara Costa-Lima & E.C.O.Chagas , E. longipetiolata Mattos , E. speciosa and E. tumescens B.S.Amorim & M.Alves ). The key encompassing these 10 species can be found in the monograph by Mazine et al. (2020), for the group named ‘Chave E’. Following this key, Eugenia stenocarpa is similar to E. bunchosiifolia because both have smooth hypanthium covered by trichomes, and leaf blades with obtuse or short-acuminate apex, sometimes rounded, with a thickened yellow revolute margin and without floccose dark indument. However, the new species is distinguished by its 25–39 mm long pedicels (vs 5–20 mm long), leaf blades with innermost marginal vein 1–4 mm from the blade edge (vs 4–6 mm), and oil glands inconspicuous above (vs raised). The key to Eugenia sect. Speciosae by Mazine et al. (2020) is updated to include E. stenocarpa and is provided below.

As already mentioned in the diagnosis, the remarkable cylindrical fruits of Eugenia stenocarpa make it clearly different from all other species in the section. Additionally, of the species that occur in the Atlantic Forest of Southeast Brazil (i.e. Eugenia bunchosiifolia , E. hermesiana , E. longipetiolata and E. speciosa ), the new species is distinguished by a set of further features, including young twigs that are sparsely puberulent and glabrescent, and flowers with pubescent hypanthium (Table).

Additional specimens examined. BRAZIL. São Paulo: Cunha, Parque Estadual da Serra do Mar, núcleo Cunha , próximo a Estrada do Paraibuna , sentido rodovia 171 (Cunha, Paraty), 23°13′44′′S, 45°00′49′′W, 1088 m alt., 3 xi 2019 [fl], A. Maruyama & L. Cicco 2045 ( ESA, SORO) ; ibid., no km 4 da Trilha das Cachoeiras, 23°16′36′′S, 45°01′59′′W, 1039 m alt., 1 x 2019 [fl], A. Maruyama & L. Cicco 1587 ( SORO) ; Zona de amortecimento do PESM, Núcleo Cunha, Sítio Vivenda das Meninas, próximo à Estrada do Paraibuna , 23°13′45′′S, 45°00′50′′W, 1102 m alt., 30 iii 2018 [fr], A. Maruyama & L. Cicco 1086 ( ESA, RB, SORO, SPSF) .

Key to Brazilian species of Eugenia sect. Speciosae (adapted from Mazine et al., 2020)

1a. Hypanthium and fruits costate _____________________________________________________ 2

1b. Hypanthium and fruits with non-costate surface ___________________________________ 3

2a. Fruits slightly 8-ribbed and pedicels swollen at the apex ____________________ E. jussara

2b. Fruits deeply 8-ribbed and pedicels not swollen at the apex _________ E. anthropophaga

3a. Hypanthium glabrous _____________________________________________________________ 4

3b. Hypanthium with trichomes _______________________________________________________ 5

4a. Leaf blades with a thickened and yellow edge, pedicel not swollen at the apex

E. speciosa 4b. Leaf blades without a thickened and yellow edge, pedicel swollen at the apex

E. tumescens

5a. Leaf blades with caudate apex and black-floccose indumentum on mature leaves

E. longipetiolata 5b. Leaf blades with acuminate, acute, obtuse or rostrate apex, glabrous or with other than black-floccose indumentum _______________________________________________________ 6

6a. Leaf blades with a thickened and yellow edge ______________________________________ 7 6b. Leaf blades without a thickened and yellow edge ___________________________________ 8

7a. Pedicels 25–39 mm long, fruit cylindrical ______________________________ E. stenocarpa 7b. Pedicels 5–20 mm long, fruit globose _______________________________ E. bunchosiifolia

8a. Leaf blades with acuminate or rostrate apex _______________________________________ 9 8b. Leaf blades with acute or obtuse apex ____________________________________________ 10

9a. Leaf blades with irregularly distributed punctuations, calyx lobes up to 3 mm long and not recovering the petals when in bud ____________________________________ E. tovomita

9b. Leaf blades with evenly distributed punctuations, calyx lobes longer than 6 mm and recovering the petals when in bud __________________________________________ E. wentii

10a. Calyx lobes with acuminate apex, 50–70 mm long _____________________ E. hermesiana 10b. Calyx lobes with acute apex, 3.9–7 mm long ______________________________ E. macedoi

Figures

Figure 1. Eugenia stenocarpa Valdemarin & A.Maruy., sp. nov. A, Twigs with flower and immature fruits; B, detail of the leaf margin, with yellow thickening; C, immature cylindrical fruit. Photograph of the holotype (K.S. Valdemarin et al. 1496), taken by K. S. Valdemarin.

Figure 2. Eugenia stenocarpa Valdemarin & A.Maruy., sp. nov. A, Flower bud; B, flower after anthesis; C, immature cylindrical fruit; D, bark. All photographs of the holotype (K.S. Valdemarin et al. 1496), taken by K. S. Valdemarin.

Figure 3. Distribution of Eugenia stenocarpa in the Atlantic Forest of São Paulo, Brazil.