Eugenia binata Mazine & Sobral, 2017

Mazine, Fiorella F., Meireles, Leonardo Dias, Sobral, Marcos & Valdemarin, Karinne Sampaio, 2017, New species of Eugenia (Myrtaceae) from São Paulo state, Brazil, Phytotaxa 296 (3), pp. 265-273 : 266-268

1. Eugenia binata Mazine & Sobral , sp. nov.

Type: — BRAZIL. São Paulo: mun. Ilhabela, Parque Estadual da Serra do Mar, estrada para Castelhanos , trilha da Água Branca, próximo das parcelas 22 e 24, 29 June 2000, J.B. Baitello, F.T. Rocha & O. T. Aguiar 1769 (holotype: BHCB!; isotypes BHCB!, SPSFphoto!). Figure 1 .

This species is related to Eugenia lomeroensis Villarroel & Gomes-Bezerra ( Villarroel et al. 2014: 316–320), being distinguished by the larger leaf blades (petioles 6–7 mm long and blades 7.5–10.4 × 3–4.1 cm vs. petioles 1–2 mm long and blades 1.5–2.6(–3) × 0.4–0.7 cm), larger flower buds (3–4 mm diam. vs. 1–2 mm diam.) and ovary densely pubescent (vs. glabrous).

Tree (height unregistered). Plants glabrous except for the flowers with ovaries densely beset with simple white trichomes to 0.1 mm. Twigs terete, sometimes moderately longitudinally striate, gray or light brown when dry, the internodes 30–50 × 1–2 mm. Leaves with petioles markedly canaliculate adaxially, 6–7 × 0.8–1 mm, usually with visible glands; blades elliptic to narrowly elliptic, 7.5–10.4 × 3–4.1 cm, 2.3–2.8 times longer than wide, drying dull green, very slightly or not at all discolorous, glabrous; glandular dots visible and raised on both sides, 4–6/mm², of unequal sizes, the larger ones to 0.1 mm diam.; apex acuminate in 6–8 mm; base cuneate; midvein finely impressed adaxially and raised abaxially; lateral veins 15–18 at each side, minutely raised on both sides, a little more so abaxially, leaving the midvein at angles of about 60 degrees; secondary lateral veins of a smaller gauge and scarcely visible; marginal veins two, the inner one 3.5–4.5 mm, the outer one 0.5–1.5 mm from the margin, the margin itself revolute and finely undulate. Inflorescences axillary or ramiflorous, racemiform, consistently biflorous, the axis 2–3 × 0.4–0.8 mm; bracts elliptic, 11.2 × 0.5 mm, glabrous, persisting; pedicels terete, 2–3 × 0.4–0.5 mm, glabrous; bracteoles elliptic, 0.9–1 × 0.7 mm, the apex rounded, glabrous, probably persisting at anthesis; flower buds obovate, 4.5–5 × 3–4 mm, ovary with scattered trichomes; calyx lobes four, in two unequal pairs, the outer ones hemispheric, 1–1.4 × 2–2.3 mm, the inner ones widely ovate, to 2 × 2.5–2.8 mm, sometimes with scattered trichomes but usually glabrous and with cilia to 0.1 mm; petals four, rounded, ca. 4 mm in diam., glabrous; stamens not counted, filaments 2.5–3 mm long in bud, the anthers globose, 0.5–0.6 mm in diam., with one connective gland; staminal ring circular to 1.7 mm in diam.; calyx tube to 0.5 mm deep; style to 3 mm, the stigma punctiform; ovary with two locules and 4–5 ovules per locule. Fruits unknown.

Distribution, habitat, and phenology: — Eugenia binata is presently known only from the type material, collected at Serra do Mar State Park, in the municipality Ilhabela, where it grows in coastal Atlantic forests. Fruits were not collected; young flowers were collected in June.

Conservation: —The Serra do Mar State Park, a mosaic of coastal Atlantic forests remnants, includes the Ilhabela municipality. It has an area of 347.5 km ² ( IBGE 2016) with about 5,000 botanical collections ( CRIA 2016), resulting in an average of 14.4 collections/km², which classifies it as having a good sampling effort. The existence of only the type collection of Eugenia binata is an indicative of its rarity, particularly when considering the high amount of collections per square kilometers at the locality. Although this locality lies in a protected area, it allows sustainable uses, specifically tourist activity, which is difficult to analyse as a risk for the habitat. The rarity of Eugenia binata could be confirmed by the area of occupancy (AOO; see IUCN 2016) estimated via Geocat ( Bachman et al. 2011) is 4 km ² (criterion B2 of IUCN 2016). Moreover, its known from just one locality and the habitat quality is declining due the anthropic pressure (criterion a(i) and b(iii) of IUCN). We suggest including Eugenia binata under the Critically Endangered (CR) category of IUCN Red List for the present.

Affinities: —Apparently related to Eugenia lomeroensis Villarroel & Gomes-Bezerra (for description see Villarroel et al. 2014), from which it is distinguished by the characters given in the diagnosis (specially the longer petioles and the hypanthium densely pubescent) and the habit (tree vs. shrub).

Etymology: —The epithet “binata ” means “twinned”, alluding the paired flowers of this species.

Taxonomic notes: —In a new ongoing phylogenetic analysis of Eugenia (Mazine et al. in prep.), Eugenia binata has been sampled and appeared as sister to “ Eugenia clade 8” ( Eugenia sect. Racemosae O. Berg ). Those authors preferred not to include this species in that clade, once it has flowers in pairs, being the only species with this flower arrangement that was sampled in that analysis. They suggest that it may consist a different clade, with a few species sharing this arrangement with flowers in pairs, very peculiar in Eugenia , as E. lomeroensis Villarroel & Gomes-Bezerra , for example. They mention that a broader sampling, in this case would be necessary.

Figures

FIGURE 1. Eugenia binata Mazine & Sobral. a. Holotype deposited at BHCB (scale 5 cm). b. Detail of inflorescences (scale 1 cm).