Eugenia abunan M. A. D. Souza & Sobral 2015, nov. sp.
Creators: name: Sobral, Marcos
name: Souza, Maria Anália Duarte De
name: Luize, Bruno G.
Publisher: name: Zenodo
Year: 2015
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Myrtales
Myrtaceae
Eugenia
Eugenia abunan

description: 2. Eugenia abunan M.A.D.Souza & Sobral, nov. sp.
Type:— BRAZIL. Rondônia: [mun. Porto Velho] Abunã, 09º38’40” S, 65º24’12” W, 4 December 2012, G. Pereira-Silva, A. Amaral-Santos, A.J.B. Santos, E.A. Santos, F.R.O. Rodrigues & V.F. Gomes 16487 (holotype INPA!; isotypes CEN, IAN!, RB!, RON!). Figure 2.
This species is apparently related to Eugenia multirimosa, from which it is distinguished through its leaves with more slender petioles (to 9 × 4 mm versus to 5 × 5 mm in E. multirimosa), blades with obtuse base (vs. cordate), with marginal vein discontinuous and arched between the lateral veins and 2–3.5 mm from the margin (vs. continuous and not arched, 5–10 mm from the margin), flowers with occasionally three calyx lobes (vs. constantly four), larger calyx lobes (to 15 × 10 mm vs. to 5 × 5 mm), absent calyx tube (vs. up to 3 mm deep) and larger staminal ring (to 4 mm in diameter vs. to 1.5 mm).
Tree to 6 m. Twigs subterete, when very young bearing narrowly triangular glabrous cataphylls to 5 × 3 mm in one or two series, when developed with brown simple trichomes to 1 mm, glabrescent with age, longitudinally striate and exfoliating in longitudinal stripes, the internodes 35–45 × 2–4 mm. Leaves with petioles 4–9 × 2–4 mm, these with grey trichomes to 0.5 mm in young leaves, glabrous with age, adaxially sulcate and transversely wrinkled abaxially; blades narrowly elliptic to obovate, 200–250 × 72–90 mm, 2.7–3 times longer than wide, discolorous, dull green adaxially and lighter abaxially, glabrous on both faces or with very scattered simple brown trichomes to 0.5 mm abaxially; glandular dots about 0.1 mm in diameter, 2 to 6 / mm² but more dense along the margins, sometimes sunken in the adaxial face; apex obtuse, the tip very abruptly acuminate to 3–6 mm; base obtuse; midvein finely raised along a central furrow adaxially, strongly raised abaxially; lateral veins 10 to 15 at each side, leaving the midvein at 45–60º, sulcate or as the midvein raised along a furrow adaxially, markedly raised abaxially; higher level venation hardly visible; marginal vein discontinuous, formed by the arches of the lateral veins, 2–3.5 mm from the margin, this revolute and with a yellowish thickening to 0.2 mm wide. Inflorescences ramiflorous or terminal, racemiform, the axis to 7 × 2 mm, pilose as the twigs, with two to eight flowers, with four to five series of glabrous cataphylls at their base, the proximal ones widely triangular, to 1 × 1.5 mm, gradually longer and narrower, the distal ones to 5 × 1 mm; bracts glabrous or ciliate, narrowly triangular, to 4 × 1 mm; pedicels 10–17 × 1–2 mm, with trichomes as the twigs; bracteoles triangular, 2–3 × 2.5–4 mm, pilose as the twigs abaxially, not connate, persisting after anthesis; flower buds elliptic, to 17 × 10 mm, uniformly covered externally by brown simple trichomes 0.5–1 mm; calyx lobes three or four, unequal in form and size between them, from widely ovate to triangular, 10–15 × 8–10 mm, sometimes tearing at the base and occasionally falling at anthesis, pilose abaxially, flower indumentum becoming scattered in flowers at anthesis, and most calyx lobes with a glabrous lighter margin; petals four, glabrous, apparently carnose, oblate or obovate, 12–18 × 15–16 mm; stamens about 300, 10–12 mm, the anthers oblong, 1.8–2 × 0.3–0.4 mm, eglandular, with white pollen visible in dried specimens; staminal ring glabrous, 4–5 mm in diameter; calyx tube absent; style not seen, fallen in the examined flowers; ovary with two internally glabrous locules, with about 30 ovules per locule. Fruits unknown.
Distribution, habitat, phenology:—This species is presently known from open riparian forests about 90 m elev. along the Madeira river in the localities of Abunã and Jirau, in the municipality of Porto Velho; flowers were collected in November and December.
Conservation:—The municipality of Porto Velho is relatively well surveyed, with about 30,200 collections (CRIA 2015) in an area of 34,096 km ² (IBGE 2015b), with an average of 0.9 collection/km²; the scarcity of collections of this species may be suggestive of its rarity. Since the specimens bear geographical coordinates, the extent of occurrence of this species was estimated via Geocat (see Bachman et al. 2011), resulting in about 140 km ² (smaller than 20,000 km ², which is criterion B1 for Endangered; see IUCN 2001); considering it was collected at only three locations (criterion B1a) along an area which may present a decline of the quality of its habitat due to human activity (dam constructions along Madeira river; criterion B1b(iii)), it must be scored as Endangered (EN) according to IUCN conservation criteria.
Affinities:— Eugenia abunan is apparently related to Eugenia multirimosa McVaugh (1956: 213; image: US barcode 00118069!), known from Peru and Amazonian Brazil, from which it can be distinguished through the characters given in the diagnosis.
Etymology:—The epithet is an apposition of the collection place of the type, Abunã, with the spelling changed to conform to Article 60 of the International Code for Nomenclature (McNeill et al. 2014).
Paratypes:— BRAZIL. Rondônia: mun. Porto Velho, Jirau, margem esquerda do rio Madeira, próximo a Mutum Paraná, December 2009, N.C. Bigio 108 (RON!); [mun. Porto Velho], Abunã, 09º38’31” S, 65º26’49” W, 5 December 2012, G. Pereira-Silva, A. Amaral-Santos, A.J.B. Santos, E.A. Santos, F.R.O. Rodrigues & V.F. Gomes 16495 (CEN, IAN!, INPA!, RB!, RON!). Porto Velho, margem direita do rio Madeira, 5 km W do porto da balsa para vila São Lourenço, parcela T6P1, 09°35’54” S, 65°02’53” W, 24 November 2013, M. F. Simon et al. 2067 (CEN, IAN!, INPA!, RON!).
description: Published as part of Sobral, Marcos, Souza, Maria Anália Duarte De & Luize, Bruno G., 2015, Three new northern Brazilian Myrtaceae, pp. 165-173 in Phytotaxa 219 (2) on pages 168-170, DOI: 10.11646/phytotaxa.219.2.6, http://zenodo.org/record/13637020