Plinia vilabela Stadnik & Sobral, 2021

Stadnik, Aline & Sobral, Marcos, 2021, Plinia vilabela (Myrtaceae), a new species from Mato Grosso, Brazil, Phytotaxa 528 (1), pp. 67-69 : 67-69

Plinia vilabela Stadnik & Sobral , sp. nov.

Type:— BRAZIL. Mato Grosso: Vila Bela da Santíssima Trindade, 15°02’44” S, 59°58’21” W, subindo o rio Alegre , 5 km S da ponte da cidade, floresta de várzea, 200 m elev., 25 March 2014, M.F. Simon et al. 2426 (holotype RB! , isotypes CEN , UFMT ). Figure 1 .

Diagnosis:—This species is morphologically related to Plinia involucrata (O.Berg) McVaugh (1969: 228 ; basionym: Myrciaria involucrata O. Berg, 1857 –1859: 375; type image W 18890212646; for description see McVaugh 1958: 779, as Plinia pinnata Linnaeus, 1753: 516 ), from which it is distinguished by its twigs with scattered trichomes to 0.2 mm (versus densely pilose, the trichomes to 0.5 mm in P. involucrata ), petioles 5–9 mm, 9–10% of the blade’s length (vs. 3–5 mm, 5–6% of the blade’s length), blades 2–2.5 times longer than wide (vs. 2.5–3.5 times longer than wide), with trichomes to 0.1 mm restricted to the midvein on both faces (vs. at least the abaxial face uniformly covered with trichomes 0.5–2 mm), the midvein mostly impressed adaxially, sometimes plane (vs. plane or raised), inflorescences with basal bracts concealing only the ovary portion (vs. concealing the entire flower buds) and flower buds with 3–5 mm long (vs. 1–3 mm long).

Description:—Tree to 8 m. Twigs terete, slightly longitudinally striate, sparsely covered with simple erect grey trichomes 0.1–0.2 mm, these falling with age, the internodes 15–22 × 1–2 mm. Leaves with petioles 5–9 × 1–1.2 mm, semiterete, adaxially plane; blades narrowly elliptic or ovate-elliptic, 55–90 × 24–40 mm, 2.2–2.5 times longer than wide, concolorous or slightly discolorous when dry, dull green or dull light brown adaxially and lighter abaxially, with simple grey trichomes 0.1–0.2 mm scattered along the midvein on both faces; base obtuse or widely cuneate, sometimes abruptly cuneate at the insertion with the petiole; apex acuminate in 5–7 mm and with a perceptible mucron 0.5–0.7 mm; glandular dots 4 to 8 / mm², visible when backlit and occasionally perceptible on the surfaces, smaller than 0.1 mm in diameter; midvein impressed adaxially or sometimes plane along its distal portion (sometimes it may appear to be raised due to the presence of trichomes), raised abaxially; lateral veins 10-12 at each side, finely raised and scarcely perceptible on both faces, leaving the midvein at angles about 60°; secondary lateral veins and higher order venation scarcely or not at all perceptible; intramarginal vein 0.8– 1 mm from the revolute margin. Inflorescences ramiflorous or axillary, with up to ten flowers densely crowded in glomerules with glabrous axes to 1 × 1 mm, with 3 to 4 series of bracts proximally, these elliptic or rounded, carenate, slightly increasing in size distally, the most basal ones to 0.5 × 0.8 mm, the most distal ones to 1.8 × 1 mm, glabrous or with sparse trichomes to 0.1 mm; bracts subtending the flowers elliptic, 1.5–2 × 1.5 mm; flowers sessile; bracteoles elliptic or ovate, separate, carenate, about the same size of the bracts and glabrous or with sparse trichomes as them; flower buds globose or obovate, 4–5 × 4 mm, pilose on the ovary, the trichomes simple, white, to 0.1 mm, usually not concealing its surface; sepals four, distinct, ovate or hemispheric, 1–1.8 × 1.5–1.8 mm, lighter than the rest of the bud when dry, glabrous or with cilia to 0.1 mm; petals four, rounded, 2.5–3 mm in diameter; stamens to 4 mm, the anthers elliptic, 0.6–0.7 × 0.4 mm, eglandular; calyx tube to 0.2 mm deep, glabrous; style to 5 mm, glabrous, the stigma punctiform; ovary with two locules and 2 ovules per locule. Fruits not seen.

Distribution, habitat and phenology:—This species is presently known only from the type specimen, collected in lowland forests (“várzea”) in the western portion of the Central Brazilian state of Mato Grosso, in the Amazonian biome; flowers were collected in March.

Conservation:—Considering that the species is presently known only from the type, we suggest it to be scored as DD (Data Deficient) following the procedure proposed by IUCN (2019: 72).

Affinities:— Plinia vilabela is morphologically related to the northern South American Plinia involucrata , with which it is compared in the diagnosis.

Etymology:—The epithet is an apposition of the name of the collection place, the municipality of Vila Bela da Santíssima Trindade.

Figures

FIGURE 1. Plinia vilabela. Holotype.