Eugenia karstica E.Barretto & Sobral, 2025

Barretto, Eduardo H. P. & Sobral, Marcos, 2025, Eugenia karstica (Myrtaceae) a new species from Minas Gerais, Brazil, Phytotaxa 704 (1), pp. 91-94 : 91-93

Eugenia karstica E.Barretto & Sobral , sp. nov.

Type:— BRAZIL. Minas Gerais, Matozinhos, Mata Lagoa da Cauaia , 24 November 2003, D.G.Rodrigues-Silva & J.D. Rosário 163 (holotype PMSP!) .

Figures 1 , 2 .

Diagnosis:— This species is morphologically similar to Eugenia complicata O. Berg (1857 –1859: 313; type images BR 000000523961, K 000276374), from which it differs by the leaves with elliptic blades, 2.2–3.2 times longer than wide (versus blades narrowly elliptic, 4–5 times longer than wide in E. complicata ), these with midvein markedly raised adaxially (vs. plane or slightly impressed), flowers with bracteoles to 1 mm long, shorter than the flower buds (vs. about 4 mm long, longer than the flower buds), and flower buds ellipsoid (vs. globose).

Description:— Trees to 3 m tall. Plants glabrous except for scattered trichomes 0.1–0.2 mm in the staminal rings and occasional cilia on reproductive parts. Twigs applanate, drying light brown; internodes to 40 × 2 mm. Leaves opposite, with petioles ca. 3 × 1 mm, semiterete, adaxially sulcate, dark when dry; blades elliptic, 61–100 × 23–39 mm, 2.2–3.2 times longer than wide, drying dark brown, concolorous or sometimes discolorous when dry, in this case light brown abaxially; glandular dots 10–15/mm², about 0.1 mm in diameter, darker than the surface and raised on both sides, a little more so abaxially; base cuneate; apex acuminate in 11–18 mm; midvein raised on both sides, darker than the surface abaxially; lateral veins 12–13, moderately raised on both sides, leaving the midvein at angles 60–70°; intramarginal vein 0.8–1.3 mm from the margin, the margin itself plane or slightly revolute, with a brown girdle about 0.1 mm wide. Inflorescences axillary, racemiform, the axis 20–45 × 1–1.5 mm, with 4–8 flowers, the peduncles 3–4 mm, the internodes 3–10 mm; bracts at the base of the inflorescence triangular, to 3 × 2 mm; bracts at the base of pedicels linear or navicular, to 4 × 1.5 mm, in both cases with cilia 0.1–0.2 mm; pedicels 4–12 × 1 mm; bracteoles narrowly triangular, persisting at anthesis, about 1 × 0.4 mm, with cilia to 0.1 mm; flower buds ellipsoid, 5–7.3 × 2.7–3.5 mm, petal globe markedly conspicuous above the sepals, the hypanthium 1.3 × 1.6 mm; sepals triangular, in two subequal pairs and somewhat connate at their bases, to 2 × 2 mm (larger and more visibly unequal in fruits), with cilia to 0.1 mm; petals four, elliptic to obovate, 5–6 × 3 mm; stamens with filaments 4–6 mm, the anthers oblong, 0.5 × 0.3 mm, with one apical gland; staminal ring subquadrate, 1.5–3 mm in diameter, 0.7–0.8 mm thick, with scattered simple white trichomes 0.1–0.2 mm; style glabrous or with very sparse trichomes 0.1–0.2 mm at the base, 5–6 mm, sometimes slightly curved downwards in its distal portion, the stigma punctiform; ovary with two internally glabrous locules, 5–9 ovules per locule. Fruits globose, 12–14 mm in diameter, with one seed, this not examined due to the scarcity of the material.

Distribution, habitat, phenology:— This species is presently known from the municipality of Matozinhos, at the central portion of the southeastern Brazilian state of Minas Gerais, a municipality which is part of the Environmental Protection Area (“Área de Proteção Ambiental”—APA) of Lagoa Santa ( Herrmann et al. 1998). It was collected in dry forests in calcareous outcrops (karsts). Flowers were collected in September and November and fruits in December and February.

Conservation:— The type specimen of Eugenia karstica was collected more than 20 years ago, and the paratypes more than 30 years ago, all of them from the same locality. We have no updated information about the environmental condition of the collection sites. The municipality of Matozinhos has an area of approximately 252 km ² ( IBGE 2025), from which there were collected about 3,000 specimens ( CRIA 2025), resulting in an average of 12 collections/km², a quite high sampling when compared to the average in Brazil, which is ca. 0.6 collection/km² ( Sobral & Stehmann 2009). Despite the high sampling effort in the area, Eugenia karstica is known from only five relatively old specimens, what can be suggestive of its rareness, but more collection efforts would be necessary for confirming it. Considering this, we propose that this species be scored DD (Data Deficient) according to IUCN conservation criteria ( IUCN 2024).

Affinities:— The racemiform inflorescences with pedicels mostly twice as long as the internodes of the axis suggest the placement of this species in section Racemosae O. Berg (1855 –1856: 278), according to the sectional classification proposed by Mazine et al. (2016). Among the species of the section, it seems morphologically close to the southeastern Brazilian species Eugenia complicata , with which it is compared in the diagnosis.

Etymology:— The epithet is derived from “karst”, the type of the rocks along the collection site.

Paratypes:— BRAZIL. Minas Gerais: Matozinhos, APA Carste de Lagoa Santa , Fazenda Cauaia , September 1995, fl., A.E. Brina & L.V. Costa ( BHCB 36673 !) ; ibidem, 30 November 1995, fl., A.E. Brina & L.V. Costa ( BHCB 36674 !, SP); ibidem, 22 December 1995, fr., A.E. Brina & L.V. Costa ( BHCB 36675 !, SP); ibidem, 2 February 1996, fr., A.E. Brina & L.V. Costa ( BHCB 36672 !).

Figures

FIGURE 1. Eugenia karstica. Holotype (photo: E. Barretto).

FIGURE 2. Eugenia karstica. A) flower bud; B) flower open with petals detached, showing stamens; C) flower open with stamens detached, showing style; D) open flower, view from above; E) adaxial surface of blade; F) abaxial surface of blade; G) inflorescences (images from the holotype; photos E. Barretto).