Myrcia colpodes Kiaersk., Enum. Myrt. Bras.

Fernandes, Thiago, Lucas, Eve J., Vasconcelos, Thais Nogales & Braga, João Marcelo Alvarenga, 2025, Extended description and taxonomic notes on two recently rediscovered Myrcia (Myrtaceae) in the Brazilian Atlantic Forest, Rodriguesia (e 00292024) 76, pp. 1-12 : 3-6

1. Myrcia colpodes Kiaersk., Enum. Myrt. Bras. 80. 1893.

Type : BRAZIL. RIO DE JANEIRO: “ Praia Grande, au Morro da Viracão ” [Municipality of Niterói, Morro da Viração, currently Parque Natural Municipal de Niterói], 12.III.1862, fl. and fr., A.F.M. Glaziou 832 (lectotype C10015833 !, designated by Lucas et al. (2016); isolectotypes BR 0000005238972 !, BR 0000005239917 , C 10015834 !, P 00161301 !) . Figs. 1 ; 2

Treelets 2–4 m, usually scarcely ramified, with pendent branches. Trunk bark vinaceous, exfoliating. Apical bud light-brown, sericeous, young leaves purplish, tomentose abaxially, young twigs tomentose, the trichomes simple, light-brown, 1–1.2 mm long. Petioles 4.6–6.5 × ca. 3 mm, most visible abaxially, adaxially sulcate, pulvinate, when young pilose like the young twigs, when mature corky and transversally fissured; blades 14.7–28.3 × 3.4–7 cm, lanceolate or spathulate, c ha r taceous, st rongly bu l late, d i scolorous, drying usually dark-brown adaxially and light-brown abaxially, apex acuminate, base obtuse or cordate; both surfaces when young sericeous to puberulent with appressed, light-brown, simple trichomes up to 0.5 mm long, visibly concentrated on the midvein, when mature glabrous or nearly so, midvein raised on both surfaces; secondary veins 10–18 mm apart, leaving the midvein at angles 55–70º, marginal veins three, the inner one 5–8 mm from the margin, the middle one 1.5–3 mm, the outer one 0.8–1 mm; glands 0.1–0.2 mm in diameter, homogeneous, hyaline, slightly raised, visible only through lens on mature leaves but visible with the naked eye, vinaceous and raised on the abaxial surface of the young ones. Conflorescence terminal, comprising a single pair, or two decussate pairs of uniflorescences, the axis from which the paired panicles develop 3–12 mm long, tomentose, subtended by sessile bracts. Uniflorescence a pendulous, pyramidal panicle, main axis 15.3–22.3 cm long, secondary branches alternate, the basal one 8.8–18 cm, penducle 27–65 × 1–1.5 mm, swollen at the point of insertion on the axil, all axes green or sometimes vinaceous in fresh state, flattened, glabrous, blackish when dry, flowers sessile; bracts subtending uniflorescences 2.3–5.4 × 2–3.4 mm, navicular, narrowly elliptic, deltoid or triangular, base truncate, apex acute, sessile, pilose as the apical bud, subtending the whole inflorescence, persisting after anthesis; bracteoles (and bracts subtending the lateral axes) 1–1.5 × ca. 0.2 mm, sessile, navicular, filiform or triangular, base truncate, apex acute, glabrous, persisting after anthesis. Flower buds 2–3 × 1.2–2.8 mm, obconic, homogeneously glabrous, with the ovary occasionally slightly darker than the calyx, petal globe partially superposed by the calyx. Flowers after anthesis with hypanthial cup ca. 0.5 mm deep, internally glabrous, not tearing at anthesis; calyx lobes five, 0.7–1.6 × 0.9–1.8 mm, slightly unequal in size (usually two larger and petaloid or deltoid, 1–2 of median size and triangular, and 1–2 smaller and cucullate with mucronate apices, of which one may be displaced downwards, resembling a displaced bracteole), reflexed, not tearing but sometimes splitting irregularly at base at anthesis, externally glabrous, internally pubescent, with whitish to amber trichomes 0.1– 0.3 mm long; petals five, 1.3–1.6 × 1.4–1.8 mm, rounded or narrowly elliptic, base truncate, apex obtuse or rounded, membranaceous, glands conspicuous, externally and internally glabrous; floral disk ca. 2.5 mm in diameter; staminal ring 0.4–0.7 mm thick, often tearing in a transversal slit, whitish, pubescent as the internal surface of the calyx, the trichomes hyaline ca. 0.2 mm long; stamens 60–65, filaments 4–5 m m long, a nt hers basi f i xed, bi loc u la r, longitudinally dehiscing with thecal margins inrolled so that the pollen is only visible through a thin slit, pseudosepta not seen but possibly hidden by thecal margins, the connective eglandular; style 7.8–8.2 mm long (around twice the stamen filaments length), stigma punctiform to slightly capitate, minutely papillose, ovary with two locules, each with two ovules. Fruits (immature) 2.8–3.5 × 2.8–3.5 mm, globose to subglobose, surface smooth, glabrous; seeds not seen.

Examined material: Rio de Janeiro , estrada das furnas da Tijuca, 24.VI.1958, fr., “Liene” [L.T. Eiten] et al. 3914 (RB). Maricá , Ponta Negra , Sacristia , à beira da praia da Sacristia , 22º56’57.1”S, 42º41’1.1”W, 64 m elev., 18.III.2022, fl., T. Fernandes et al. 1006 (NIT, NY, K, RB, US); 2.V.2022, fl., T. Fernandes et al. 1013 (NIT, NY, RB); 5.VII.2022, fl., T. Fernandes et al. 1060 (NIT, K, RB); 23.VIII.2023, fr., T. Fernandes & R. Benvenuti 1484 (NIT, RB); divisa dos municÍpios de Maricá e Tanguá, Espraiado, Refúgio da Vida Silvestre de Maricá, trilha para o Pico da Lagoinha, 22º51’26”S, 42º40’1”W, 700 m elev., 22.IX.2024, D.N.S. Machado 3571 (RFFP, RB).

Myrcia colpodes is endemic to the Brazilian state of Rio de Janeiro, with records restricted to the municipalities of Maricá (from the rediscovered populations), Niterói (from the type collection) and Rio de Janeiro capital city (from a collection from 1958) ( Fig. 3 ). This species inhabits inselberg forests near the sea at ca. 64 m elev. and montane rainforests at ca. 700 m elev. Flowers can be found from mid-March to August, fruits (immature) were collected only once in June.

Myrcia colpodes can be recognized in the field by its vinaceous and exfoliating trunk, young purplish and pendular leaves, lanceolate and strongly bullate mature leaves, pendulous, glabrous uniflorescences, in well-developed panicles, and externally glabrous flowers. This overall aspect fits the morphological concept of Myrcia sect. Aulomyrcia . Within this section, the characteristic long leaves with adaxially raised midveins, the terminal conflorescences with well-developed and whorled uniflorescences, combined with flower buds with free calyx lobes, suggests its placement in “species group A” as circumscribed in Lucas et al. (2016: 652). Myrcia colpodes is remarkable within this group due to its pubescent staminal ring, which contrasts with the internally glabrous flowers present in all other species of this group occurring in the Atlantic Forest.

Within the “species group A” of Myrcia sect. Aulomyrcia , bullate leaves also occur in the Amazonian species M. integra M.A.D. Souza & Sobral (in Sobral et al. 2015: 212) and M. maraana Sobral & M.A.D. Souza (in Sobral et al. 2015: 222), as well as in M. gigantea (O.Berg) Niedenzu (1895: 76) an Atlantic Forest species endemic from the Brazilian state of Bahia ( Santos et al. 2020). These species also share subsessile leaves with barely visible petioles, but they can be distinguished by the characters given in Table 1 .

Figures

Figure 1 – a-j. Myrcia colpodes in fresh state – a. trunk with papery plates attached; b. trunk after bark peeling; c. young leaves; d. adaxial surface of leaves, detail: midvein raised; e. abaxial surface of leaves, detail: petioles slightly pulvinate and tomentose; f. fflowering branch with flower buds (detail: uniflorescences swollen at base in upper arrowhead, and bracts subtending uniflorescences in lower arrowhead); g. pendular inflorescence; h. detail of a typical terminal portion of uniflorescences axes, flower buds and a terminal post-anthetic flower; i. post-anthetic flowers after stamen fall, showing the sericeous staminal ring and the long style; j. immature fruit. (a-f. Fernandes 1006; g-i. Fernandes 1060; j. Fernandes 1484). Photos: a-b. Thiago Fernandes; c-i. Carlos Ferreira.

Figure 2 – a-e. Myrcia colpodes in dry state – a. leaf adaxial surface (detail: raised midvein); b. leaf abaxial surface (detail: corky petiole and tomentose indumentum); c. detail of a typical terminal portion of uniflorescences axes with flower buds; d. post-anthetic flowers showing the pubescent staminal ring; e. lateral view of an immature fruit. (a-c. Fernandes 1006; d. Fernandes 1060; e. Fernandes 1484).

Figure 3 – Map with the current known occurrence records ofMyrcia colpodes and M.rubiginosa. White lines represent limits between municipalities in the state Rio de Janeiro.