Plinia tapuruquarana M.A.D.Souza & Sobral, 2017

Sobral, Marcos & Souza, Maria Anália Duarte De, 2017, Four new Myrtaceae from Amazonian Brazil, Phytotaxa 307 (1), pp. 55-64 : 63

4. Plinia tapuruquarana M.A.D.Souza & Sobral , sp. nov.

Type : BRAZIL. Amazonas: [Mun. Santa Isabel do Rio Negro], Tapuruquara, 19 October 1971, G. T. Prance, P. J. Maas, D. B. Woolcott, O. P. Monteiro & J. F. Ramos 15713 (holotype MG!; isotypes INPA!, NY). Figure 4 .

Diagnosis: —This species is apparently related to Plinia pinnata Linnaeus (1753: 516) , from which it differs by its wider blades (to 150 × 85 mm and less than three times longer than wide versus to 150 × 40 mm and more than three times longer than wide in P. pinnata ), petioles about 3.5 times longer than wide (vs. about 7 times longer than wide) and larger flowers (buds to 12 × 10 mm vs. up to 4 × 4 mm).

Description: —Tree to 5 m. Twigs slightly complanate, when young densely covered with brown or purple trichomes to 0.1 mm, these falling with age and then the twigs are grey and somewhat exfoliating, the internodes 45–70 × 2–3 mm. Leaves with petioles terete, 8–11 × 1.8–2.5 mm, glabrous, blackish when dry; blades ovate-lanceolate or lanceolate, 95–165 × 36–70 mm, 2.3–2.8 times longer than wide, glabrous, slightly discolorous when dry, dark brown adaxially and lighter abaxially, glandular dots smaller than 0.1 mm in diameter and ca. 15/mm², visible and moderately raised abaxially; apex acuminate in 12–24 mm; base widely cuneate; midvein strongly raised on both sides; lateral veins 15–20 at each side, leaving the midvein at angles 70–80°, moderately raised on both sides; marginal vein 1–3 mm from the moderately revolute margin. Inflorescences axillary or ramiflorous, with up to six sessile, glomerate flowers along an axis to 2 mm; bracts not seen; bracteoles obovate, to 5 × 3 mm, with simple grey trichomes to 0.2 mm, more densely so abaxially; flower buds globose to obovate, 10–12 × 10 mm, either uniformly and densely covered with simple grey trichomes 0.5–1 mm or with trichomes more dense along the proximal half; calyx lobes four, more or less equal between them, elliptic or widely elliptic, 4–5 × 4 mm, glabrous or somewhat pubescent adaxially; petals four, rounded or obovate, densely covered with simple white trichomes to 0.1 mm on both faces; stamens not counted, to 10 mm, the anthers oblong, to 0.8 × 0.3–0.4 mm, eglandular; staminal ring 3–4 mm in diameter, with trichomes as the lobes; calyx tube to 3 mm deep, sparingly pubescent; style glabrous, 12–15 mm, the stigma punctiform; ovary with two locules and two ovules per locule. Fruits immature, oblate, to 28 × 31 mm, longitudinally 8-ridged; seed not examined due to the scarcity of the material.

Distribution, habitat and phenology: —This species is known from two collections in the northwestern portion of the state of Amazonas. It was collected in forests near Negro river; flowers were collected in October and fruits in May.

Conservation: —Considering the existence of only two collections made more than 40 years ago, it is not possible to assess confidently any conservation status for the species; so, it must be therefore scored as DD (Data Deficient) according to IUCN conservation criteria ( IUCN 2001).

Etymology: —The epithet is derived from the collection site, Tapuruquara.

Affinities: —This species is apparently related to Plinia pinnata (for description see Amshoff 1951: 98; no type image available online), from which it is distinguished by the characters given in the diagnosis. It is noteworthy that Rogers McVaugh (1909–2009) the long-lived myrtologist who devoted many years of his prolific career working on Amazonian Myrtaceae , has spotted this species as new in 1972—but then abandoned his research on the Myrtaceae and did not described it.

Paratype: — BRAZIL. Amazonas: [possibly São Gabriel da Cachoeira] Rio Negro, entre a ponta da ilha Marauiá e Massarabi, no caminho para Uaupés, 1 May 1973, M.F.Silva, P. Machado & O. Pires 1195 (INPA!).

Figures

FIGURE 4. Plinia tapuruquarana. Holotype (scale: 50 mm).