Eugenia rhytidocalyx 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 rhytidocalyx

description: 5. Eugenia rhytidocalyx M.A.D.Souza & Sobral, sp. nov.
Type:— BRAZIL. Amazonas: [Manaus], along Manaus-Boa Vista Road (BR-174), km 415, 75 m, 13 November 1977, L. Coradin & M.R. Cordeiro 1077 (holotype INPA!; isotypes CEN, NY). Figure 5.
Diagnosis:—This species is related to Eugenia quadriovulata, from which it differs by its smaller blades (to 80 × 26 mm versus up to 120 × 50 mm in E. quadriovulata) with acute to widely acuminate apex (vs. markedly acuminate), glandular dots not impressed, visible only abaxially (vs. markedly impressed-punctate and visible on both sides), marginal vein one, to 1 mm from the margin (vs. marginal veins two, 2–3 mm and 1 mm from the margin), inflorescences occasionally auxotelic (vs. auxotelic inflorescences absent), flowers pedicellate (vs. sessile) and pilose hypanthium (vs. glabrous).
Description:—Tree to 3 m. Plants mostly glabrous, except for trichomes in inflorescences and flowers. Twigs slightly applanate, reddish when young, turning grey. Leaves with petioles adaxially sulcate, 3.5–4 × 0.9–1 mm; blades elliptic to narrowly elliptic, 55–80 × 22–26 mm, 2.4–3 times longer than wide, discolorous, dull dark brown adaxially, dull rufescent brown abaxially; base cuneate; apex widely acute to widely acuminate in 2–8 mm; glandular dots 10 to 15/mm², of unequal sizes, the largest dots to 0.1 mm in diameter, more visible abaxially; midvein moderately impressed or occasionally plane adaxially, moderately raised abaxially; lateral veins 12 to 15 at each side, leaving the midvein at angles about 60°, finely but perceptibly raised adaxially, a little more so abaxially; secondary lateral veins visible; marginal vein to 1 mm from the margin, with approximately the same gauge as the main lateral veins and raised in the same way; margin visibly revolute. Inflorescences ramiflorous, glomerate, with two to six flowers arising from a node, sometimes with a small central axis to 1 × 1 mm, or auxotelic, with up to four flowers on the basal portion of a branch that develop normal leaves; bracts oblong to elliptic, 0.5–1 × 0.3 mm, with simple rufescent trichomes to 0.1 mm; pedicels 1.5–2.5 × 0.3 mm, with ascending rufescent trichomes to 0.1 mm; bracteoles widely ovate, free or slightly connate at their bases, to 1 × 1 mm, glabrous or with cilia to 0.1 mm, sometimes slightly carenate, persisting at anthesis; flower buds obovate, 2.5–3 × 1.5 mm; hypanthium to 1 mm, minutely covered by rufescent or grey trichomes to 0.1 mm; calyx lobes four, mostly glabrous, glandulose and markedly rugose abaxially, in two slightly unequal pairs, rounded, 1.2 × 1.2–1.3 mm; petals obovate or spathulate, 2.6–3 × 1.7 mm, glandulose, glabrous and ciliate; stamens not counted, the filaments to 3 mm, the anthes elliptic, 0.4 × 0.2–0.3 mm, with one apical gland; staminal ring to 1.5 mm in diameter, glabrous; calyx tube absent; style to 4 mm, glabrous, the stigma punctiform; ovary with two internally glabrous locules, with two ovules per locule. Fruits not seen.
Distribution, habitat and phenology:—This species is known only from the type, collected in the municipality of Manaus in upland forests (“terra firme”); flowers were collected in November.
Conservation:—Considering that this species was collected in the municipality of Manaus, one of the most surveyed places in the state of Amazonas (see data under Eugenia breviacuminata), the existence of only one collection may be an indication of its rareness; nevertheless, in the absence of additional information we score it as DD (Data Deficient) according to IUCN conservation criteria (IUCN 2001).
Etymology:—The epithet is derived from the Greek words for “rugose” and “calyx”, alluding to the characteristic morphology of the calyx of this species.
Affinities:—This species is morphologically related to Eugenia quadriovulata Amshoff (1942: 160; for additional descriptions see Amshoff 1951: 120 and McVaugh 1969: 209; type image NY 00405001), a species presently known to Suriname, from which it is distinguished by the characters cited in the diagnosis. Amshoff compares E. quadriovulata with Eugenia coffeifolia De Candolle (1828: 272) on the basis of the presence of two ovules per locule; nevertheless, this character may not necessarily represent a phylogenetic signal, since ovule reduction apparently occur in other unrelated Eugenia such as species of section Hexachlamys (O.Berg) Mazine (2016: 228; basionym: Hexachlamys O. Berg, 1855 –1856: 345) (Sobral, personal observation). Considering the glomerate inflorescences, this species should be assigned to section Umbellatae O.Berg, according to the phylogenetic scheme of 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 26-28, DOI: 10.11646/phytotaxa.349.1.2, http://zenodo.org/record/13709225