Eugenia leucogyna Sobral 2021, sp. nov.
Creators: name: Sobral, Marcos
name: Lima, Duane F.
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Myrtales
Myrtaceae
Eugenia
Eugenia leucogyna

description: 1. Eugenia leucogyna Sobral, sp. nov.
Type:— BRAZIL. Pará: Altamira, Near Embrapa station at km 23 on road Altamira-Itaituba, 29 October 1977, C.C. Berg, A.S. Silva, R.P. Bahia & M.R. dos Santos 739 (holotype RB!, isotype NY). Figure 1.
Diagnosis:—This species is morphologically related to Eugenia egensis De Candolle (1828: 281; image M 0137682), but differs by its pilose blades, inflorescences and flowers (versus consistenly glabrous in E. egensis).
Description:—Trees to 6 m. Twigs subterete, densely covered with simple erect grey trichomes to 1 mm, these falling with age and then becoming slightly longitudinally striate, the internodes 20–35 × 1.5–2.5 mm. Leaves with petioles 2–3 × 1 mm, semiterete, drying black; blades elliptic to narrowly elliptic, 77–100 × 31–50 mm, 1.9–2.6 times longer than wide, discolorous when dry, dull dark brown or dark green adaxially and lighter abaxially, with simple grey or rufescent trichomes 0.5–1 mm along the midvein adaxially and more uniformly dispersed, perceptible by touch, along the abaxial surface; base cuneate; apex acuminate in 7–12 mm; glandular dots 6 to 15/mm², usually visible and darker than the surface abaxially, smaller than 0.1 mm in diameter; midvein slightly impressed adaxially and raised abaxially; lateral veins 15 to 18 at each side, leaving the midvein at angles of 70–80°, finely raised on both faces; secondary lateral veins and higher order venation scarcely perceptible; intramarginal vein 1.5–3.5 mm from the slightly revolute margin. Inflorescences axillary or ramiflorous, racemiform, with 6 to 18 flowers in opposite pairs, the axes 5–15 × 0.5–0.8 mm, densely covered with whitish simple erect trichomes to 0.5 mm, the internodes 1–3 mm; bracts triangular, to 1 × 1 mm, deciduous at anthesis; pedicels pilose as the axes, 2–8 × 0.5 mm, diminishing in size distally along the same axis; bracteoles elliptic, 2–3.5 × 1–1.5 mm, separate from each other, carenate, occasionally with trichomes to 0.5 abaxially or at least ciliate, deciduous at anthesis; flower buds globose or subglobose, 4–5 mm in diameter, the ovary markedly covered by simple white erect trichomes to 0.5 mm, occasionally concealed by the bracteoles; sepals four, glabrous along the surface but with cilia to 0.3 mm, glandulose, in two unequal pairs, the smaller ones ovate or hemispheric, 1.3–2.5 × 2–2.5 mm, the larger ones elliptic, 3–3.5 × 3 mm; petals 4, rounded or elliptic, to 4 × 4 mm; stamens with filaments to 4 mm, the anthers elliptic, to 0.6 × 0.2 mm, mostly eglandular or with a very inconspicuous apical gland; staminal ring 2–2.3 mm in diameter and 0.8 mm wide, with trichomes to 0.2 mm; calyx tube absent; style 6–7 mm, glabrous, the stigma punctiform; ovary with two internally glabrous locules and 6 to 9 ovules per locule. Fruits not seen.
Distribution, habitat and phenology:—Collected in Amazonian upland rainforests; flowers in October and November.
Affinities:— Eugenia leucogyna is related to the widespread South American Eugenia egensis, with which it is compared in the diagnosis. Regarding its sectional placement, due to its inflorescence structure, it is possibly placed in Eugenia section Umbellatae O. Berg (1855 –1856: 204), according to the sectional classification of Mazine et al. (2016, 2018).
Conservation:—The three specimens examined were collected in the neighboring municipalities of Altamira and Vitória do Xingu, about 30 km apart from each other; Altamira is the largest municipality in Brazil, with an area of nearly 160,000 km ², while Vitória do Xingu has an area of 3,000 km ² (data from IBGE 2020); there are registered respectively 4,800 and 1,150 botanical collections from these municipalities (data from INCT 2020), resulting in the amount of 0.03 and 0.4 collections / km² respectively, a poor sampling effort in both cases. Considering this, it seems adequate to score this species as DD (Data Deficient) according to IUCN conservation criteria (IUCN 2017).
Etymology:—The epithet is derived from the Greek words for “white” and “ovary”, alluding to the whitish indumentum of the flowers.
Paratypes:— BRAZIL. Pará: Vitória do Xingu, 03°11’59” S, 51°48’48” W, 28 November 2014, M.L.C. de Faria PSACF_EX 04493 (RB!, SORO); idem, 27 January 2015, A.C. Gonçalves PSCAF_EX04845 (RB!, UB).
description: Published as part of Sobral, Marcos & Lima, Duane F., 2021, Three new Brazilian Myrtaceae, pp. 277-284 in Phytotaxa 483 (3) on pages 277-281, DOI: 10.11646/phytotaxa.483.3.7, http://zenodo.org/record/5420988