Eugenia curuba Costa-Lima

Costa-Lima, James Lucas Da & Chagas, Earl Celestino De Oliveira, 2018, Six new species of Eugenia (Myrtaceae) from the Atlantic Forest of northeastern Brazil, Phytotaxa 373 (3), pp. 211-220 : 214-216

3. Eugenia curuba Costa-Lima & E.C.O.Chagas, sp. nov. ( Fig. 2A–D )

Eugenia curuba is different from the other species of Eugenia sect. Umbellatae from northeastern Brazil by the large, globose, and woody fruits. It is distinguished from Eugenia pruinosa by the leaf blades obtuse to rounded (vs. acute to acuminate) at the apex, secondary veins 12–14 (vs. 12–22) per side, sessile (vs. pedicellate; i.e., pedicels 6–8 mm long) fruits with subtly glandular-rugose (vs. markedly rugose) surface.

Type: — BRAZIL. Alagoas: Mun. Murici, Estação Ecológica de Murici, Fazenda Bananeiras, 14 September 2012 (fr), M. C. S. Mota & E. C. O. Chagas 11756 (holotype MAC!).

Trees, ca. 10 m tall; bark exfoliating; branches glabrous, brownish when young, greyish when older. Petioles 6– 8 mm long, puberulent. Leaf blades 4.7–7.8 × 3–4.5 cm, elliptic to round-elliptic, chartaceous, without glandular dots, discolorous, shiny adaxially, glaucous abaxially, glabrous on both surfaces, apex obtuse to rounded, margin revolute, base acute to obtuse; midvein impressed adaxially, prominent abaxially, secondary veins 12–14 per side, with distinct gridiron pattern, slightly impressed adaxially, prominent abaxially, the marginal vein 1–3 mm from the margin. Flowers not seen; floral bracts not seen; sepals 4 (measured in fruits), in subequal pairs, the outer ones 1.2– 2.5 × 2.5–4 mm, the inner ones 1–1.5 × 2.2–3 mm, hemispheric, glabrous, apex rounded. Fruits axillary, 1–2 per node, sessile, 42–48 × 30–34 mm, ovoid, woody, glabrous, subtly glandular-rugose, smooth, orangish to yellowish when ripe, crowned by the calyx lobes, lobes erect; 1-seeded.

Etymology: —The name comes from the Old Tupi word “ curuba ,” which means acorn or grain ( Barbosa 1951, Navarro 2013), due to the large size and shape of the fruits.

Distribution and habitat: —This species occurs in the state of Alagoas, in northeastern Brazil, in rainforest subcanopy.

Conservation status: —As well as Eugenia cambemba , E. curuba can be considered as Critically Endangered [CR B12ab(i,ii,iii)], according to IUCN (2017) criteria. Presently, cattle farming near the area where the species occurs is the main threat to the maintenance of the populations of E. curuba . The region is also fragmented due to past cultivation of sugar cane.

Discussion: — Eugenia curuba is known only from fruiting material with sessile, axillary fruits, suggesting that it is related to species with glomeruliform inflorescences, such as those of Eugenia sect. Umbellatae , as circumscribed by Mazine et al. (2016). It is distinct from all other species of Eugenia that occur in the Atlantic Forest of northeastern Brazil by the presence of abaxially glaucous leaf blades, puberulent petioles, and notably large and woody fruits. It is morphologically similar to Eugenia pruinosa Legrand (1961: 323) , from E. sect. Umbellatae, which occurs in Atlantic Forest areas from Espírito Santo to Santa Catarina, in eastern and southern Brazil ( BFG 2015), and can be distinguished by the features shown in the diagnosis.

Figures

FIGURE 2. E. curuba. A. Fruiting branch, in sicco (scale: 5 cm). B. Leaves, highlighting the glaucous abaxial surface. C. Fruiting branch. D. Fruits. Eugenia jussara. E. Immature fruit. F. Fruiting branch, highlighting the basally swollen fruit pedicels (arrows). G. Fruit in sicco, with surface detail. H. Fruiting branch, in sicco (scale: 5 cm).All photographs by the authors.