Myrcia damaniensis R. Flores , B. Holst & A. Ibáñez, 2022

Flores, Rodolfo, Holst, Bruce K. & Ibáñez, Alicia, 2022, Two new species of Myrtaceae from the western Caribbean forests of Panama, Phytotaxa 568 (1), pp. 61-71 : 64-66

1. Myrcia damaniensis R. Flores, B. Holst & A. Ibáñez sp. nov.

Type:— PANAMA. Comarca Ngäbe-Bugle: Humedal de Damani-Guariviara, Laguna de Damani. Vegetación de laguna, 5 m, 8°55’47”N, 81°41’45”W, 7 June 2013 (fl.), R. Flores, A. Ibáñez, N. Flores, A. Espinosa, T. Santiago & H. Taylor 3081 (holotype: PMA!) Figure 3 , Figure 4 A-C .

Diagnosis: — Myrcia damaniensis is similar to Myrcia chytraculia ( Linnaeus 1759: 1056) A.R. Lourenço & E. Lucas (in Lourenço et al. 2018: 74) var. americana ( McVaugh 1963: 404) G.P. Burton & E. Lucas (in Burton et al. 2021: 1023). Nevertheless, it can be easily distinguished by the size of its leaves (<15 cm vs.> 15 cm), leaf blades, elliptic, widely elliptic or suborbicular (vs. elliptic-ovate) and leaves with nearly indiscernible or weakly evident secondary venation on both surfaces (vs. leaves with prominent venation on abaxial surface). The apex in both species can be acuminate but M. damaniensis can also have a caudate or cuspidate apex.

Description: —Shrubs or trees, 4–8 m; young leaves and branchlets, petioles and inflorescences with appressed reddish-brown indument; trichomes dibrachiate; branchlets terete, young branchlets slightly complanate and compressed at nodes. Leaves opposite, petiolate, the petioles 6–11 × 1–1.5 mm, channeled, with scattered trichomes; blades elliptic, widely elliptic or suborbicular, 7–12.2 × 3.5–6.5 cm, chartaceous, adaxial surface with scattered trichomes, green when fresh, brown, light brown or greenish-brown when dry, abaxial surface sparsely pubescent, green when fresh and light brown when dry, glands inconspicuous but visible at 10×; apex caudate or cuspidate, abruptly acuminate or acuminate; base acute or acuminate; midvein adaxially sulcate and depressed distally, with a few scattered trichomes, abaxially prominent, convex, distally attenuating, sparsely pubescent; lateral veins 13–24 per side, nearly indiscernible or weakly evident on adaxial and abaxial surfaces, ascending from the midvein to a marginal vein which equals the lateral veins in prominence and is slightly arched between ca. 1.8–2 mm from the margin. Inflorescences panicles, branched, densely covered with appressed, reddish brown trichomes, subterminal, one or two per axil, 8–12 × 3–7 cm, ca. 100 flowers per panicle, peduncle 3–7 cm × 1–1.2 mm, slightly winged and mostly distally flattened, axes angulate to quadrangular, bracts not seen.

Flowers with pedicels 0.5–1 mm long; bracteoles caducous, densely covered with appressed trichomes, ca. 0.7 × 0.3 mm, lanceolate or narrowly lanceolate, apex acute; buds 1.8–2.3 mm long (including hypanthium), ovoid, densely covered with appressed trichomes; hypanthium ca. 1.2 mm long, prolonged ca. 1 mm beyond the summit of the ovary, densely covered with appressed trichomes, calyptra ca. 2 mm wide, shortly apiculate; petals absent; stamens ca. 20; anthers reniform, ca. 0.3 mm long; filaments ca. 2–3 mm long. Ovary bilocular, 2 ovules per locule; style ca. 4–5 mm long; stigma punctate. Fruit globose, 3–5 × 3–6 mm, crowned by the hypanthium, glabrescent and pubescent towards the apex, pericarp thin-walled, less than 1 mm thick. Seeds one or two, 2.5–6 mm diameter, globose or semi–spheroid.

Distribution, habitat and phenology:—This species has been found on the shores of Damani and Oiba lagoons and along the channels of the wetland, in areas of mixed swamp forest with abundant Campnosperma panamense ( Fig. 2A ). One flowering specimen was collected in June, and fruiting specimens in September and October.

Conservation:— Myrcia damaniensis has been found only in the Damani region, within the protected area Damani-Guariviara Wetlands of International Importance. Despite its protected status, the forests in the area are being cut down for subsistence agriculture and cattle ranching by an increasing population. This situation may reduce its small area of occupation (AOO) which is estimated just at 4 km ²; therefore, we consider that this species fits the category Endangered [EN B2ab (ii, iii, iv)] of the IUCN Red List and criteria ( IUCN 2012).

Etymology:—The epithet of this species refers to the Damani lagoon, the largest in the Damani-Guariviara Wetlands.

Discussion:— Myrcia damaniensis has the calyx lobes fused into a single structure that opens circularly through a calyptra. Based on this morphological characteristic, this species would belong in Myrcia sect. Calyptranthes ( Swartz 1788: 79) A. R. Lourenço & E. Lucas , according to a recent phylogenetic study ( Lucas et al. 2018: 3).

Myrcia damaniensis is apparently related to Myrcia chytraculia var. americana . Both species have inflorescences alate, multiflorous and covered with a reddish pubescence. However, both species are distinguished by the characters listed in the diagnosis.

With the description of Myrcia damaniensis , 34 species of Myrcia are recognized in Panama.

Paratypes:— PANAMA. Comarca Ngäbe-Bugle: Humedal de Damani-Guariviara , laguna de Oiba, vegetación de laguna, 5 m, 8°50’57”N, 81°38’05”W, 17 September 2011 (fr.), A . Ibáñez & R . Flores 7377 ( PMA!, UCH!); Humedal de Damani-Guariviara , laguna de Damani, vegetación de laguna (orilla), 5 m, 8°55’56”N, 81°42’35”W, 19 September 2011 (fr.), R . Flores & A . Ibáñez 1415 ( PMA!, MO!); Humedal de Damani-Guariviara, Cerari , bosque inundable, 16 m, 8°56’34”N, 81°42’27”W, 26 October 2014 (fr.), R . Flores & T . Santiago 3647 ( PMA!, SEL!) .

Figures

FIGURE 2. Habitats where the new species grow.A.Swamp forests around a lagoon in Damani-Guariviara wetland, habitat of both Myrcia damaniensis and Eugenia tain. B. Inside a swamp forest with abundant Symphonia globulifera (tree with aerial roots) and Campnosperma panamense, habitat of both Myrcia damaniensis and Eugenia tain. C. Coastal forest in Escudo de Veraguas island. Habitat of Eugenia tain (tree on the left). Photos by A. Ibáñez.

FIGURE 3. Myrcia damaniensis. Holotype specimen.

FIGURE 4. Myrcia damaniensis and Eugenia tain. A–C. Myrcia damaniensis. A. Flowering branch. B. Flowering branch showing underside of leaves. C. Fruiting branch. D–F. Eugenia tain. D. Flowering branch showing underside of leaves. E. Detail of flower showing reflexed petals at anthesis. F. Fruiting branch. Photos by A. Ibáñez.