Myrcia barbata, a new species of Myrcia sect. Myrcia (Myrtaceae) from São Paulo, Brazil.

Myrcia (Myrciinae, Myrteae, Myrtaceae) is one of the most diverse genera of Neotropical angiosperms, with ca. 790 species. In the Brazilian state of São Paulo, 11 species of Myrcia sect. Myrcia have been identified, being characterized by a hypanthium not or only slightly extended longitudinally above the ovary apex, non-gomidesioid anthers, and a calyx divided into five sepals. During taxonomic studies in the montane dense ombrophilous forest of Parque Estadual da Serra do Mar-Núcleo Cunha (PESM-NC), in São Paulo state, a population that does not correspond to any previously known species of Myrcia sect. Myrcia was found. After detailed morphological analyses and comparisons with type specimens and original descriptions, we describe it as a new species. Myrcia barbata sp. nov. is morphologically similar to M. bracteata in the presence of golden hirsute indumentum on the branches and leaves measuring 3–10 cm in length, as well as bracteoles subtending the floral buds, but differs by having elliptic leaves (vs. lanceolate), inflorescences arranged in three-flowered dichasia (vs. panicles with 8–20 flowers), sessile leaves (vs. shortly petiolate, 1–3 mm), a densely pubescent hypanthium (vs. pubescent to sericeous), obtuse-triangular sepals (vs. lanceolate), and ovate bracteoles (vs. elliptic). Myrcia barbata also resembles M. eriopus, sharing hirsute young branches and leaves 3–10 cm long, in addition to bracteoles subtending the floral bud. Myrcia barbata differs from M. eriopus by its elliptic (vs. lanceolate) leaves, inflorescences reduced to three-flowered dichasia (vs. panicles with 10–25 flowers), discolorous (vs. concolorous) leaves, sessile leaves (vs. shortly petiolate, 1.8–3 mm), revolute (vs. flat) leaf blade margins, a densely pubescent (vs. hirsute) hypanthium, and conspicuous (vs. inconspicuous) bracteoles. We provide a list of Myrcia sect. Myrcia species recorded in São Paulo State (including Myrcia bracteata, which is not found in São Paulo), as well as a dichotomous identification key and comparative data table including morphological characters such as branch and leaf morphology (shape, size, color, indumentum), leaf blade margin, petiole length, inflorescence type, bracteole and sepal features, hypanthium indumentum, and fruit characteristics. Known only from the type locality, the new species occurs 1,100 m above sea level and flowers between September and January. Myrcia barbata exhibits an extremely restricted distribution inside a conservation site but the low number of known individuals led to the classification of its conservation status as Data Deficient.

Project(s)

Priority 4: Accelerated Taxonomy

Funder

Funder name	Awards
Reflora, Brazil	200992/2024-4
Conselho Nacional de Desenvolvimento Científico e Tecnológico, Brazil	200992/2024-4 - 305105/2022-1
Jardim Botânico do Rio de Janeiro, Brazil	200992/2024-4
Ministério da Ciência, Tecnologia e Inovação, Brazil	MCTI/FINEP Convênio 01.25.0110
Financiadora de Estudos e Projetos	MCTI/FINEP Convênio 01.25.0110
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, Brazil	Finance Code 001