Myrcia excelsa T.Fernandes & Gaem, 2021

Gaem, Paulo Henrique, Fernandes, Thiago, Valdemarin, Karinne Sampaio, Lucas, Eve & Mazine, Fiorella Fernanda, 2021, Myrcia excelsa (Myrtaceae), a new species from Espírito Santo, Brazil, Phytotaxa 501 (2), pp. 293-296 : 293-295

Myrcia excelsa T.Fernandes & Gaem , sp. nov.

Type:— BRAZIL. Espírito Santo: Linhares, Reserva Florestal da CVRD, estrada da Gávea , próximo a uma boleira, 20 July 1979, D.A. Folli 81 (holotype CVRD! ; isotypes BHCB, RBR, SORO!, UEC) . Figure 1 .

Diagnosis: —Similar to Myrcia riodocensis , differing in having a persistent cortex in mature branches (vs. exfoliating), leaf blades with midvein adaxially raised or biconvex (vs. canaliculate) and strongly revolute margins (vs. flat), and claviform flower buds (vs. obovoid) with all ovate sepals (vs. two triangular and two ovate). Also similar to Myrcia scytophylla , differing in having petioles 2–5 mm (vs. 5–12 mm), strongly revolute leaf margins (vs. flat), smooth inflorescence axes (vs. glandular), deciduous bracteoles (vs. persistent after anthesis), and pedicellate, claviform flower buds (vs. sessile and obovoid) with the calyx obscuring the enclosed corolla just before anthesis (vs. not obscuring).

Trees to 28 m tall; crown to 8 m wide; trunk to 19 m tall, cylindrical, circumference at breast height to c. 170 cm, bark rough or flaky, usually peeling off. Branches with persistent cortex, glabrous when mature, terete, smooth or minutely rough; branchlets glabrous, terete or subterete, smooth; internodes 0.9–5 cm. Leaves with a glabrous petiole 2–5 mm, subterete or sulcate, smooth or corky; blade glabrous on both surfaces, coriaceous, concolourous, 7.2–14.5 × 2.7–5.2 cm, elliptic, ovate, or slightly obovate, base slightly cordate, rounded, or less often obtuse, apex obtuse, acuminate, or caudate, midvein biconvex adaxially, raised abaxially, lateral veins 10–20 at each side, raised on both surfaces, marginal veins two at each side, the outer somewhat straight, the inner arched and 3–5 mm from margins, margins strongly revolute; oil glands scarcely visible with the naked eye, 5–7 per square mm. Inflorescences paniculiform, 3.9–17 cm, emerging in groups of 3–6 on the axils of terminal leaves, twice compound; basal bracts thinly sericeous abaxially, glabrous adaxially, 2–3 mm, triangular, persistent after anthesis; peduncle glabrous, 2.2–4 cm; branches glabrous, flattened, smooth, alternate or opposite, the lateral ones 0.6–3 cm; bracts subtending branches not seen, deciduous before anthesis; bracteoles glabrous, ca. 1.5 mm, linear, deciduous before anthesis; pedicels glabrous, 0.5–1.5 mm. Flower buds 3–4 × 1.5–2 mm, claviform; hypanthium glabrous on both surfaces, smooth, 2–3 mm, extended as a tube beyond the summit of the ovary; perianth 4(–5)-merous, calyx formed by small sepals at the apex of the bud, these fused at the base, tearing at anthesis, glabrous and glandular externally and thinly sericeous internally, ca. 1.5 × 1 mm, ovate; petals obscured by the calyx before anthesis, glabrous, ca. 2 × 1 mm, ovate; stamens glabrous, filament ca. 3.5 mm, anthers reversing curvature at dehiscence; style glabrous, ca. 6 mm, stigma punctiform; disc glabrous, concave; staminal ring glabrous; ovary 2-locular, with two ovules per locule. Fruits glabrous, glandular, 1.3–1.6 × 1–1.3 cm, obloid, crowned by the hypanthial tube, calyx persistent or occasionally deciduous. Seed single or two per fruit, ca. 1.2 × 0.9 cm, testa shiny and papery, embryo with leafy, folded cotyledons and a welldeveloped, folded hypocotyl.

Distribution and habitat: —This species has been recorded in Tabuleiro forests in the municipalities of Linhares and Pinheiros, Espírito Santo state, Brazil.

Preliminary conservation assessment: — Myrcia excelsa is known from 9 localities and has an Extent of Occurrence of ca. 1,800 km ² and an Area of Occupancy of 36 km ², occurring in forest fragments immersed in an anthropic landscape ( SOS Mata Atlântica & INPE 2020). In this context, it may have been facing habitat loss in extension, area, and/or quality. Therefore, this species is evaluated as Endangered [EN, B1,2ab(i–iii)] according to the IUCN criteria.

Phenology: —Flowers were collected from May to July, and fruits were collected in August, September, and November.

Etymology: —Based on the Latin ‘ excelsus ’ (excelling, surpassing), the specific epithet is a reference to the size of individuals of this species. Together with Myrcia subacuminata ( Kiaerskou 1893: 50) M.F.Santos in Santos et al. (2019: 7) and M. plusiantha Kiaerskou (1893: 66) , M. excelsa is among the tallest trees in the genus to inhabit the Atlantic forest ( Legrand & Klein 1971, Lannoy et al. 2021).

Vernacular name: — Myrcia excelsa has been called araçati near to the type location according to labels of specimens.

Affinities: — Myrcia excelsa can be assigned to M. sect. Aulomyrcia (O. Berg 1855: 35) Grisebach (1860: 234) sensu Lucas et al. (2018) based on its extended hypanthia, sepals partly torn at anthesis, glabrous flower discs, anther thecae reversing curvature at dehiscence, and 2-locular ovaries. Within this section, the new species is most similar to the sympatric Myrcia riodocensis G.M. Barroso & Peixoto (1990: 13) due to a reddish colour in most parts of the preserved materials, scarce indumentum, a tendency for rounded or cordate leaf blade bases, and usually a 4-merous perianth. Myrcia excelsa also resembles the Amazonian M. scytophylla ( Diels 1907: 187) E.Lucas & C.E.Wilson in Lucas et al. (2016: 692) in having glabrous branchlets and leaves, leaf blades with the midvein adaxially raised or biconvex, persistent basal inflorescence bracts, and usually a 4-merous perianth. While Myrcia riodocensis belongs to the informal species group D of M. sect. Aulomyrcia sensu Lucas et al. (2016), M. scytophylla is placed in species group C. Thus, as a result of this incongruence and uncertainty an informal group is not speculated for Myrcia excelsa in this work.

Paratypes: — BRAZIL. Espírito Santo: Municipality of Linhares, Floresta Nacional de Goytacazes , estrada municipal Jataipeba, 19°27’49”S, 40°04’18”W, 10 August 2010, D.A. Folli 6650 ( CVRD, SORO!) ; 15 August 2011, J.M.L. Gomes 3875 ( VIES!) ; Reserva Biológica de Comboios, ao lado da fazenda Catavento , 22 May 1989, G.L. Farias 274 ( CVRD, K, RB, SORO!, UEC) ; Reserva Natural Vale, aceiro LASA , 26 September 2006, D.A. Folli 5360 ( CVRD!, SORO!) ; 28 September 2006, G.S. Siqueira 246 ( CVRD!, SORO!) ; estrada do Flamengo , km 10,25, próximo a um Arixixá, 02 June 1972, A.M. Lino 78 ( BHCB, CVRD!, RB!) ; estrada da Gávea , 22 November 1988, D.A. Folli 818 ( ASU, CVRD!, K, RB!, SORO!) ; 07 June 2007, M.C. Souza et al. 538 ( RB!) ; Municipality of Pinheiros, córrego Santa Rita, fazenda Joventino Altoé , 20 June 1990, M. Gibran 138 ( CVRD, SORO!, SPF) .

Figures

FIGURE 1. Myrcia excelsa. A. fruiting branch. B. flowering branch. C. flower bud, top view. D. open flower. E. fruit, side view. F. fruit, top view. G. embryo. H. flower bud, side view (A,G: D.A. Folli 5360; B,H: D.A. Folli 81; C: G.L. Farias 274; D: M. Gibran 138; E,F: D.A.Folli 6650). All photographs taken from material deposited at the SORO herbarium.