Myrcia auxotelica Sobral & Antunes 2018, sp. nov.
Creators: name: Sobral, Marcos
name: Antunes, Kelly
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Myrtales
Myrtaceae
Myrcia
Myrcia auxotelica

description: Myrcia auxotelica Sobral & Antunes, sp. nov.
Type:— BRAZIL. Rio de Janeiro: Itatiaia, Parque Nacional, arredores do Lago Azul, 13 October 1994, R. Simão-Bianchini & S. Bianchini 539 (holotype SP, isotype HUFSJ!). Figure 1.
Diagnosis:—This species is morphologically related to the Central American Myrcia fosteri Croat (1974: 886), from which it differs by its tetramerous flowers and mostly auxotelic inflorescences (versus pentamerous flowers and anthotelic inflorescences in M. fosteri).
Description:—Shrub to tree 1.5–6 m high. Twigs terete, longitudinally striate, whitish or brown, densely covered with white, grey or brown simple trichomes to 0.5 mm when young, these becoming scarce or absent with age. Leaves with petioles 3–4 × 0.6–1 mm, semiterete, adaxially sulcate, with simple trichomes to 0.3 mm and sometimes with dark linear colleters to 0.5 × 0.1 mm basally; blades elliptic or narrowly elliptic, sometimes ovate, 50–63 × 12–25 mm, 2.2–4.5 times longer than wide, when young pilose as the twigs, the indumentum falling with age, when adult discolorous when dry, the adaxial face shining brown or dull dark green, glabrous or essentially so except for trichomes 0.2–0.3 mm along the midvein, the abaxial face dull light brown or light green, usually with trichomes 0.3–0.4 mm usually denser along the midvein and sometimes distributed along the entire surface; glandular dots 4 to 6/mm², smaller than 0.1 mm in diameter, sometimes visible abaxially but usually evident only when backlit; base obtuse or rounded, rarely cuneate; apex acuminate in 6–13 mm; midvein finely sulcate adaxially and markedly raised abaxially; lateral veins 15 to 20 at each side, leaving the midvein at angles 60–80°, finely impressed adaxially and moderately raised abaxially, with visible secondary lateral veins slightly thinner than the main ones; marginal vein 0.2–0.5 mm from the margin, the margin itself revolute and with a yellow girdle to 0.1 mm thick. Inflorescences axillary or in ramiflorous brachyblasts, with one or two pairs of flowers, in this case simulating a raceme but auxotelic— i.e. “that continue growth beyond the flowering region”; see Briggs & Johnson 1979: 241 —, with normal leaves developing after the flowers (very rarely inflorescences may have three flowers along an anthotelic—”ending in a flower”; Briggs & Johnson 1979: 241 —axis to 10 × 0.3 mm, in this case the flowers sessile); bracts elliptic, 2–3 × 1 mm, pilose as the twigs, deciduous at anthesis; with 3 to 5 linear colleters to 1 × 0.1 mm at the base, these dark when dry and contrasting with the light trichomes; pedicels 5–10 × 0.2–0.3 mm, with trichomes to 0.3 mm; bracteoles linear, 3–3.5 × 0.2–0.3 mm, adaxially glabrous and sparsely pilose abaxially, usually deciduous at anthesis but sometimes persisting even in fruits, with three to five persisting colleters to 0.5 × 0.1 mm at the base; flower buds globose or obovate, to 3 × 2.8–3 mm, the hypanthium to 0.8 mm, more densely pilose than the calyx lobes, these four, triangular, all about the same size, 2–2.2 × 2 mm, markedly reflexed at anthesis, pilose on both faces but more so externally, usually with an apical tuft of trichomes to 0.5 mm; petals four, elliptic or widely elliptic, 2.5–3.5 × 2–2.5 mm, glabrous or with scattered trichomes abaxially; staminal ring to 2.2 mm in diameter, 0.7–0.8 mm thick, with trichomes to 0.2 mm; stamens not counted, incurved in bud, the filaments to 3 mm and the anthers elliptic, to 0.3 × 0.2 mm, with one connectival gland; hypanthium tube absent or to 0.3 mm deep; style 3–4 mm, pilose at the base, the stigma punctiform; ovary with two locules and two ovules per locule. Fruits elliptic, red when ripe, 6–7 × 3–3.5 mm, crowned by the calyx lobes; seed to 5 × 3 mm, the testa brown, easily detachable, the embryo with one well developed hypocotyl and two discrete convoluted cotyledons.
Distribution, habitat and phenology:—This species was collected in rainforests and high altitude fields in the southeastern Brazilian states of Minas Gerais and Rio de Janeiro, at altitudes about 1000 m elev.; flowers were collected in January, September, October and November; fruits were collected in February and November.
Conservation:—An estimate via Geocat (Bachman et al. 2011) of the extent of occurrence (EOO) of Myrcia auxotelica resulted in about 22,000 km ²; such an EOO suggests a status of Near Threatened (NT), according to the conservation criteria proposed by IUCN (2001).
Etymology:—The epithet is allusive to the inflorescence structure of the species.
Affinities:—Although the embryo morphology clearly assigns this species to Myrcia, flowering specimens may be confounded with Eugenia Micheli ex Linnaeus (1753: 470) due to its mostly uniflorous inflorescences and tetramerous flowers; nevertheless, the presence of two ovules per locule is usual in Myrcia and rare in Eugenia, and the stamens are visibly incurved in bud, while they are straight in Eugenia (Vasconcelos et al. 2015). This species is morphologically related to the Central American Myrcia fosteri (type image: MO barcode MO-187156), with which it is compared in the diagnosis. The flower morphology, with a staminal ring comprising more than 60% of the floral disk and very short or absent hypanthium tube, is suggestive of its inclusion in Myrcia section Myrcia, according to the phylogenetic scheme proposed by Lucas et al. (2018). Due to its tetramerous flowers and acuminate blades, Myrcia auxotelica may also remind the northern South American M. bolivarensis (Steyerm.) McVaugh (1969: 81; basionym: Aulomyrcia bolivarensis Steyermark, 1957: 1004; type image U barcode 0005098), but in this species inflorescences are also many-flowered and anthotelic; additionally, M. bolivarensis has a well developed hypanthium tube and belongs to Myrcia section Aulomyrcia (O.Berg) Grisebach (1864: 234; basionym: Aulomyrcia O. Berg, 1855 –1856: 35). The acuminate blades and solitary flowers could also remind the northern Brazilian Myrcia uaioai Sobral & Souza (2015: 224; type image INPA 42104), but the flowers in this species are pentamerous and definitely axillary.
Paratypes:— BRAZIL. Minas Gerais: Lima Duarte, Parque Estadual da Serra do Ibitipoca, mata do Monjolinho, 21°41’ S, 43°52’ W, 24 November 2004, R. Forzza, D. Pifano, C.M. Sakuragui, L.Y.S. Aona, S. Edwards & D. Zappi 3682 (BHCB!, RB!). Mariana, região da Mina de Fábrica Nova, 20°11’50” S, 43°25’56” W, 25 February 2008, S.G. Rezende, M.S. Mendes & G.S. Neves 2527 (BHCB!, HUEFS, HUFSJ!). Olaria, Serra Negra, Degredo, 1 December 2012, K. Antunes, J.H.C. Ribeiro, F.R. Salimena, P.H. Nobre & M. Magalhães 364 (CESJ, HUFSJ!). Rio de Janeiro: Itatiaia, Parque Nacional de Itatiaia, Lago Azul, margem do rio Campo Belo, 15 October 1995, J.M.A. Braga 2897 (HUFSJ!, NY, RB!); Itatiaia, Parque Nacional de Itatiaia, trilha para Cachoeira Poranga, 6 November 1995, J.M.A. Braga 2946 (HUFSJ!, RB!); Itatiaia, Parque Nacional de Itatiaia, Maromba, trilha para Cachoeira Itaporani, 30 September 1996, S.J. Silva Neto 886 (HUEFS, HUFSJ!, NY, RB!, SPF, MBML!). Teresópolis, Montanha do Ricardo, 14 January 1883, J. Saldanha (R 164357!).
description: Published as part of Sobral, Marcos & Antunes, Kelly, 2018, Myrcia auxotelica, a new southeastern Brazilian Myrtaceae, pp. 297-300 in Phytotaxa 379 (4) on pages 297-299, DOI: 10.11646/phytotaxa.379.4.4, http://zenodo.org/record/13726310