Eugenia longa M. A. D. Souza & Sobral 2018, sp. nov.
Creators: name: Souza, Maria Anália Duarte De
name: Sobral, Marcos
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Myrtales
Myrtaceae
Eugenia
Eugenia longa

description: 3. Eugenia longa M.A.D. Souza & Sobral, sp. nov.
Type:— BRAZIL. Amazonas: Itacoatiara, estrada para Itapiranga próximo a Águas de Lindoia, Serra da Lua, Rio Urubu, entre Cachoeira Iracema e Cachoeira Natal, 6 June 1968, G.T. Prance, D. Philcox, W.A. Rodrigues, J.F. Ramos & L.G. Farias 5032 (holotype INPA!; isotypes NY, US, K, S, MG!, F, U, A, MICH, MO, COL, VEN). Figure 3.
Diagnosis:—This species is morphologically related to Eugenia ramiflora, from which it is distinguished by its longer, narrower blades (to 300 mm long and 7–8 times longer than wide versus up to 150 mm and less than 5 times longer than wide in E. ramiflora), the midvein adaxially impressed (vs. adaxially raised) and glabrous fruits (vs. pilose).
Description:—Tree to 4 m. Twigs glabrous, terete, light brown or grey when dry, very finely longitudinally striate. Blades with petioles 8–10 mm, adaxially sulcate, glabrous, black when dry; blades narrowly oblong, 225–300 × 28–42 mm, 7–8 times longer than wide, chartaceous, discolorous when dry, glabrous, dark green and shining adaxially, dull light brown and densely covered by an arachnoid indumentum abaxially, the trichomes brown and up to 0.1 mm; glandular dots of different sizes, the larger ones about 0.1 mm in diameter and 2 to 3/mm² and occasionally visible and slightly darker than the surfaces on both sides, the smaller ones more dense, with up to 10/mm² and visible only when backlit; base cuneate; apex acuminate in up to 20 mm; midvein finely impressed and occasionally becoming plane or very slightly impressed along the distal half of the blades adaxially, markedly raised and darker than the surface abaxially; lateral veins 40 to 50 at each side, finely raised on both sides, more markedly so adaxially, leaving the midvein at angles 70–80°, intermixed with numerous secondary lateral veins of approximately the same gauge; marginal veins two, the inner one 2–3 mm, the outer one 0.3–0.5 mm from the moderately revolute margin. Inflorescences axillary or ramiflorous, fasciculiform, with an axis up to 2 × 1 mm, with two flowers; fasciculate; bracts ovate, to 2 × 1 mm, glabrous; pedicels 4–5 × 0.8 mm, applanate, densely covered with trichomes as the blades; bracteoles deltoid, to 1 × 2.5 mm; flowers not seen. Fruits globose, to 7 mm in diameter, red when ripe, minutely and densely glandulose, crowned by four persisting glabrous calyx lobes in two unequal pairs, the outer ones hemispheric, 0.8–1 × 0.7–1, the inner ones widely ovate, 1.8–2 × 2 mm; staminal ring in fruits glabrous, to 2 mm in diameter; seed reniform, to 7 × 5 mm, with brown, easily detachable testa and embryo with fused cotyledons and no visible hypocotyl.
Distribution, habitat and phenology:— Eugenia longa is known only from the type collection, from the municipality of Itacoatiara, where it grows on sandy soils along floodable forest (“igapó”); fruits were collected in July.
Etymology:—The epithet is allusive to the long blades of the species.
Conservation status:—The municipality of Itacoatiara has an area of 8892 km ² (IBGE 2017), from where there are 1494 known collections (CRIA 2017), resulting in the weak sampling effort of 0.16 collection/km²; the existence of only one collection of Eugenia longa may be due rather to the scarce sampling in the area rather than its rarity. Considering it, we score this species as DD (Data Deficient) according to IUCN conservation criteria (IUCN 2001).
Affinities:— Eugenia longa is morphologically related to the Amazonian Eugenia ramiflora Desvaux ex Hamilton (1825: 43; type image FI 011511), with which it is compared in the diagnosis. Considering its fasciculiform inflorescence structure, it must be assigned to section Umbellatae, according to the phylogenetic scheme proposed by Mazine et al. (2016).
description: Published as part of Souza, Maria Anália Duarte De & Sobral, Marcos, 2018, Six new Eugenia (Myrtaceae) from Amazonas, Brazil, pp. 18-30 in Phytotaxa 349 (1) on pages 22-24, DOI: 10.11646/phytotaxa.349.1.2, http://zenodo.org/record/13709225