Myrcia cupreiflora T. Fern. & J. M. A. Braga 2024, sp. nov.
Creators: name: Fernandes, Thiago
name: Gaem, Paulo Henrique
name: Vasconcelos, Thais N. C.
name: Bovini, Massimo Giuseppe
name: Braga, João Marcelo Alvarenga
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Myrtales
Myrtaceae
Myrcia
Myrcia cupreiflora

description: Myrcia cupreiflora T.Fern. & J.M.A.Braga, sp. nov.
Type:— BRAZIL. Rio de Janeiro: Mangaratiba, Ilha Guaíba, trilha que atravessa a praia do Raposo até a Tapuá, 23º00’10”S, 44º02’25”W, 21 June 2023, fl., M.G. Bovini & G. Falcão 4763 (holotype RB 01495553!). Figures 1–3.
Diagnosis:—This new species is morphologically similar to Myrcia strigipes Mart. (1841: 108), from which it can be distinguished by leaf blades strongly bullate and densely punctate abaxially (vs. smooth and not punctate in M. strigipes), and inflorescences and flowers with coppery indumentum, without epidermal peeling (vs. yellowish indumentum, with epidermal peeling).
Description:—Trees 6–7 m tall. Young twigs flattened, strigose, trichomes coppery, 0.4–0.8 mm long, mature branches cylindrical, brownish, rugose, internodes 2.5–5.5 cm long. Leaves with petioles 4.8–9.6 × 2.3–3.2 mm, adaxially sulcate, smooth or corky, blades 16.7–24.3 × 5.4–8.4 cm, strongly bullate, chartaceous, slightly discolorous, elliptic or oblong-lanceolate, base obtuse to slightly cordate, apex cuspidate, adaxially with canaliculate midvein, impressed secondary veins, slightly raised reticulation, inconspicuous glands, glabrescent, with remnant trichomes concentrated on the midvein, abaxially with raised venation and densely covered with darkened, raised glands ca. 0.1 mm in diameter, sometimes with persistent trichomes like those of the young twigs, especially along the midvein; secondary veins ca. 18 at each side, leaving the midvein at angles of 40–45º, marginal veins two, the inner one 3–3.5 mm from the margin, in prominent arches, the outer one 1–1.2 mm from the margin, almost continuous. Inflorescences axillary-terminal, 1– 2 pairs, paniculiform, strigose, trichomes coppery, 0.4–0.8 mm long, the axes slender and curved when dry, main axis 7–21 cm long, basal secondary axes 2.5–9.2 cm long; bracts subtending secondary axes and bracteoles 1–1.8 x 0.3–0.5 mm, linear, apex acute, strigose, often persisting until fruit development. Flower buds 3–4 × 2–3.2 mm, obovoid, densely glandulous, strigose, trichomes coppery, 0.4–0.8 mm long, denser on the ovary; calyx completely fused, apex rounded; corolla absent; flowers after anthesis not seen; calyx (in fruit) 4–5-merous, sepals 1.4–2.7 × 1.4–1.7 mm, triangular, externally densely glandulous, strigose, internally glabrous, tearing deeply vertically; hypanthium tube ca. 0.5 mm deep, externally densely glandulous, strigose, internally glabrous; stamens ca. 105. Fruits (immature) 7–10 × 7–10 mm, globose, puberulent, glandular, crowned by the reflexed sepals.
Distribution, habitat and phenology:— Myrcia cupreiflora is presently known only from the Brazilian state of Rio de Janeiro, where it inhabits two rainforest fragments ca. 25 km apart, one of them being an island (Figure 4). Flower buds were collected in June, immature fruits in August and October.
Preliminary conservation status:—All occurrence points of Myrcia cupreiflora fall within a protected area (Área de Proteção Ambiental de Mangaratiba), but a continuing decline in extent and quality of the habitat can be inferred for the area, extent and quality of the habitat, mainly from tourism, urbanization and activities related to local shipping (INEA 2015). Additionally, the species occur in only two locations, and has an Extent of Occurrence (EOO) of 79 km ². For these reasons, Myrcia cupreiflora is here assessed as Endangered (EN), following IUCN criteria (2012, 2022).
Etymology:—The specific epithet, from the Latin cupreus, meaning shiny brownish red, refers to the distinctive coppery, strigose indumentum on the flowers (and inflorescences) of this new species.
Affinities:— Myrcia cupreiflora is morphologically similar to M. strigipes (see the diagnosis). The strongly bullate leaf blades and long, axillary-terminal inflorescences of Myrcia cupreiflora are also reminiscent of those of M. colpodes Kiaerskou (1893: 80), from which it can be promptly distinguished by the strigose inflorescences (vs. glabrous in M. colpodes), and calyx completely fused in the flower buds (vs. free), tearing deeply vertically at anthesis (vs. opening regularly without vertical tearing).
Paratypes:— BRAZIL. Rio de Janeiro: Mangaratiba, Itacuruçá, 1 October 2008, fr., C.Y’G. Manão 373 (RB 00549568!); Mangaratiba, Ilha Guaíba, trilha que vai da praia do Tapuá até o Bambuzal, 23º00’27”S, 44º02’42”W, 31 August 2023, fr., M.G. Bovini 4787 (RB 01500033!).
description: Published as part of Fernandes, Thiago, Gaem, Paulo Henrique, Vasconcelos, Thais N. C., Bovini, Massimo Giuseppe & Braga, João Marcelo Alvarenga, 2024, Myrcia cupreiflora (Myrtaceae), a new species from the Brazilian state of Rio de Janeiro, pp. 95-100 in Phytotaxa 663 (2) on pages 96-99, DOI: 10.11646/phytotaxa.663.2.5, http://zenodo.org/record/14515820