Myrcia longisepala B. S. Amorim 2018, sp. nov.
Creators: name: Amorim, Bruno S.
name: Alves, Marccus
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Myrtales
Myrtaceae
Myrcia
Myrcia longisepala

description: Myrcia longisepala B.S. Amorim sp. nov. (Figures 1, 2 A–C.)
Type:— BRAZIL. Espírito Santo: Aracruz, A.I. do Limão, 17 June 2009, fr., L.D. Thomaz, J.M.L. Gomes & V.B. Sarnaglia-Júnior 1828 (holotype: VIES!; isotypes: HUFSJ, UFP!).
Treelet up to 3 m tall, closely related to M. congestiflora Caliari & V.C. Souza in Caliari et al. (2016: 202) but differing by smaller leaves (6.5–10.5 cm long; vs. 16–24.5 in M. congestiflora), fewer secondary leaf veins (10–12 pairs; vs. 18–20 pairs in M. congestiflora), smaller petioles (0.3–0.4 cm; vs. 0.5–0.7 cm long in M. congestiflora) and smaller fruits (0.7–0.8 × 0.8–0.9 cm; vs. 0.9–1.6 × 0.9–1.6 cm in M. congestiflora).
Treelet up to 3 m tall; young stems pubescent, simple trichomes; leaf decussate, blade elliptic to lanceolate, 6.5–10.5 × 2.4–3.7 cm, flat adaxially, membranaceous (when dry), base cuneate, apex acuminate, acumen 1 cm long, appressed simple trichomes (<1 mm long) abaxially and adaxially, strigose; midvein flat with puberulent white trichomes (when dry) adaxially, and raised with pubescent redish trichomes abaxially, secondary veins 10–12 pairs, diverging at 60– 70º from the midvein, marginal vein 2–3 mm from the margin, inframarginal vein not visible or 1 mm from the margin; petiole 0.3–0.4 cm long, flat adaxially, and abaxially, puberulent, covered by yellowish trichomes (when dry). Inflorescence panicule, reduced, main axis 1.5 cm long, pubescent, multi-flowered, flowers clustered at the apex; bracts not seen, deciduous; bracteoles not seen, deciduous; flowers not seen, calyx lobes five, in fruit 4 mm long, rounded, pubescent (yellowish trichomes when dry); petals not seen; stamens persistent in immature fruit, ca. 200, filaments 5–6 mm long, reddish (when dry), the anthers ca. 1 mm long, elliptc, thecal displaced opening, septum not visible; staminal ring 3 mm in diameter, puberulent; style and stigma not seen; hypanthium prolonged 1 mm beyond the ovary; ovary 2-locular with 2-ovules per locule. Fruit 0.7–0.8 × 0.8–0.9 cm, subglobose to globose, smooth, pubescent, calyx lobes persistent.
Affinities:—It is morphologically similar to Myrcia carvalhoi Nic Lughadha (Lughadha et al. 2012b: 235), M. cerqueiria (Nied.) E. Lucas & Sobral (Sobral et al. 2010: 54; basionym: Gomidesia cerqueiria Niedenzu 1893: 78), and M. congestiflora, which share reduced inflorescence main axis with flowers clustered at the apex, but differs by its smaller leaves 6.5–10.5 cm long (vs. 15–29 cm long in M. carvalhoi and M. congestiflora), smaller petiole 0.3–0.4 cm long (vs. 0.5–1 cm in M. cerqueiria and M. congestiflora), leaf with appressed trichomes abaxially (vs. ascending to erect trichomes in M. carvalhoi), leaf with 10–12 pairs of secondary veins (vs. 12–14 pairs in M. carvalhoi, 14–16 pairs in M. cerqueiria and 18–20 pairs in M. congestiflora), calyx lobes 4 mm long (vs. 1–2 mm long in M. cerqueiria and 2–3 mm long in M. carvalhoi), and smaller fruits 0.7–0.8 × 0.8–0.9 cm (vs. 1.3–1.4 × 1.3–1.4 cm in M. carvalhoi and 0.9–1.6 × 0.9–1.6 cm in M. congestiflora); see table 1 for a detailed comparison.
Distribution and habitat:— Myrcia longisepala is endemic of Atlantic Forest and restricted to lowland coastal forests from Espírito Santo state in southeastern Brazil. The lowland forests of the Espírito Santo state are currently well studied by floristic surveys (Pereira & Araújo 2000, Assis et al. 2004, Rolim et al. 2016, Souza et al. 2016), including specific efforts for Myrtaceae (Giaretta & Peixoto 2015, Giaretta et al. 2016). These areas are one of the most Myrtaceae species-rich in Espírito Santo state and also important due to the endemism of Myrcia s.l. species (Murray-Smith et al. 2009, BFG 2015, Giaretta et al. 2015). Based on that, Myrcia longisepala is another example which highlights the species richness and high endemism of that area.
Phenology:—Fruiting from May to July.
Etymology:—The epithet “ longisepala ” refers to the long calyx lobes of this species, an uncommon morphological feature in the Gomidesia clade species.
Conservation status:—This species is known only for the type locality. Due to the high collection efforts and large number of studies in the Atlantic Forest of the Espírito Santo state described above, we concluded that Myrcia longisepala is a rare species with restricted occurrence. Based on that, the species meets the criteria of Vulnerable (VU; criterion D).
description: Published as part of Amorim, Bruno S. & Alves, Marccus, 2018, New narrowly distributed species of Myrcia s. l. (Gomidesia clade, Myrtaceae) from the Atlantic Forest of southeastern Brazil, pp. 182-188 in Phytotaxa 343 (2) on pages 183-184, DOI: 10.11646/phytotaxa.343.2.9, http://zenodo.org/record/13718656