Eugenia seislagoana M. A. D. Souza & Sobral 2022, sp. nov.
Creators: name: Souza, Maria Anália Duarte De
name: Sobral, Marcos
name: Amorim, Gabriela
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Myrtales
Myrtaceae
Eugenia
Eugenia seislagoana

description: 5. Eugenia seislagoana M.A.D.Souza & Sobral, sp. nov.
Type:— BRAZIL. Amazonas: São Gabriel da Cachoeira, Morro dos Seis Lagos, igarapé Yá-Mirim, 0.28333333, -66.691666, 180 m elev., 26 May 2008, M.H. Terra-Araújo 287 (holotype INPA!, isotype HUFSJ!). Figure 7.
Diagnosis:—This species is morphologically related to Eugenia illepida McVaugh (1956: 210; for additional description see McVaugh 1958: 704; type images NY 00404930, S 05-2904, US 00118002), but differs by the blades with midvein adaxially biconvex (versus flat or sulcate in E. illepida), secondary lateral veins and higher order venation perceptible, the surfaces visibly reticulate (vs. scarcely or not perceptible), bracteoles triangular to 1.5 mm (vs. lanceolate, to 2.5 mm), glabrous flowers (vs. pilose), sepals about the same size, 4–6 × 4–4.5 mm (vs. two unequal pairs, 4 × 7 mm and 8 × 14 mm), ovary externally with 8 longitudinal ridges (vs. smooth) and locules with up to 10 ovules each (vs. about 30).
Description:—Trees 2.5 m. Plants glabrous. Twigs terete or applanate, dark brown when dry, longitudinally striate, the internodes 25–80 × 4–5 mm. Leaves with petioles 11–17 × 2–3 mm, dark when dry, longitudinally striate and adaxially sulcate; blades elliptic to oblong or ovate-oblong, 165–210 × 68–90 mm, 1.8–2.9 times longer than wide, discolorous when dry, dark brown or dull dark green adaxially, dull light brown abaxially; base widely acute or rounded, sometimes the blade conduplicate there; apex acute or widely acute, with an acumen 3–10 mm, this sometimes also conduplicate; midvein adaxially biconvex, moderately raised along the blade, abaxially strongly raised and frequently longitudinally striate; lateral veins 15–20, raised on both sides, more so abaxially, leaving the midvein at angles 60–70°; secondary lateral veins and higher order venation perceptible and a little more finely raised on both sides; intramarginal veins usually two,the inner one 3–3.5 and the outer one to 2 mm from the visibly revolute margin, the margin itself with a yellowish girdle to 0.2 mm wide. Inflorescences axillary or ramiflorous, fasciculiform, the axis not developed, with 1–2 flowers; pedicels 9–12 × 1 mm, applanate, somewhat wider distally; bracteoles triangular, 1.2–1.5 × 1 mm, persisting at anthesis; flower buds glabrous, obpyriform, 10–12 × 7–10 mm, the calyx concealing the globe of the petals in bud; sepals four, in two slightly unequal pairs, 4–6 × 4–4.5 mm, elliptic–oblong to triangular, the sepals slightly fused to 1 mm or less on their basal portions, tearing at anthesis; petals elliptic or narrowly elliptic, 8–15 × 10– 8 mm (petals rosy, according to collection Araújo 287); stamens with filaments to 10 mm and the anthers narrowly elliptic, to 2 × 0.6 mm, the thecae opening longitudinally, with one apical gland; staminal ring glabrous, 3 mm in diameter; calyx tube absent; style to 10 mm, the stigma punctiform; ovary externally 8-costate, with two locules and 8–10 ovules per locule, these strongly coalesced and hardly separable. Fruits ellipsoid, to 25 mm and 18 mm in diameter, immature in the specimen examined (green with whitish punctuations, according to collection Assis 40), with eight perceptible longitudinal ridges, these to 1 mm wide and raised from the surface of the fruit in less than 1 mm; seed not examined due to the scarcity of material.
Distribution, habitat and phenology:—Collected in shallow rocky soils in the Morro dos Seis Lagos National Reserve, in the northwestern portion of the state of Amazonas; flowers were collected in April and May, and fruits in May.
Affinities:—This species is morphologically close to the northern Brazilian Eugenia illepida, with which it is compared in the diagnosis. The fasciculiform inflorescences suggest its placement in Eugenia section Umbellatae, according to the sectional classification proposed by Mazine et al. (2016, 2018).
Conservation:—The municipality of São Gabriel da Cachoeira has an area of 109,181 km ², and there are recorded about 14,000 collections from there, resulting in a sampling index of about 0.1 collection/km², a low sampling effort (see comment under E. canumana). All known specimens of Eugenia seislagoana were collected along a small area of 3 km ² (calculated via Geocat 2020); although this extent of occurrence (EOO, see IUCN 2012: 11) suggests a high threat level, additional information on population decline or fluctuation is wanting; considering this, we suggest the status of DD (Data Deficient) for this species, following IUCN guidelines (IUCN 2019: 78).
Etymology:—The epithet is allusive to the collection place of the studied specimens, Morro dos Seis Lagos.
Paratypes:— BRAZIL. Amazonas: São Gabriel da Cachoeira, Morro dos Seis Lagos, Igarapé Yá-Mirim, 0.28333333, -66.693611, 270 m elev., 20 April 2008, R.L. Assis, J.R.M. Ferreira & M.H. Terra-Araújo 40 (HUFSJ!, INPA!); ibidem, 0.28666666, -66.683888, 268 m elev., 24 May 2008, M.H. Terra-Araújo 232 (HUFSJ!, INPA!).
description: Published as part of Souza, Maria Anália Duarte De, Sobral, Marcos & Amorim, Gabriela, 2022, Six new species of Eugenia (Myrtaceae) from Amazonian Brazil, pp. 197-212 in Phytotaxa 536 (3) on page 209, DOI: 10.11646/phytotaxa.536.3.1, http://zenodo.org/record/6331824