Miconia rufibarbis (Triana) Gamba & Almeda

  • Family

    Melastomataceae (Magnoliophyta)

  • Scientific Name

    Miconia rufibarbis (Triana) Gamba & Almeda

  • Primary Citation

    Systematics of the octopleura clade of Miconia (Melastomataceae: Miconieae) in tropical America
    Phytotaxa 179: 1--174. 2014

  • Basionym

    Ossaea rufibarbis Triana

  • Description

    Description Author and Date: Diana Gamba & Frank Almeda, modified from "Systematics of the Octopleura Clade of Miconia (Melastomataceae: Miconieae) in Tropical America". Gamba, D., Almeda, F. Phytotaxa 179(1): 1-174.

    Type: COLOMBIA (Novae Granatae). Nariño (Prov. de Barbacoas), 800 m, May 1853, Triana 3929 (holotype: BM-internet image!; isotypes: COL-internet image!, BR-internet image!, P; fragment: US; photographs: F!, MO!).

    Description: Shrub or small little-branched tree, rarely epiphytic, (1.2–)1.5–5 m tall, bark rusty-green. Upper internodes[(2–)2.8–8.5 cm long] and cauline nodes terete, bearing a well defined nodal ridge that is confluent with the abaxial bases of the petioles. Indumentum on branchlets, petioles, adaxial surface of young leaves, primary and secondary leaf veins abaxially, inflorescence axes, bracts and bracteoles abaxially, hypanthia, calyx lobes and calyx teeth copiously to moderately covered with hispid elongate trichomes 2–3 mm long with greatly roughened (substellate) bases, sparsely intermixed with an understory of dendritic trichomes ca. 0.2 mm long with short thin-walled (flattened) arms. Leaves of each pair isophyllous; the petiole 0.5–2.5 cm long, widely canaliculate and depressed adaxially, erect and nearly parallel to the subtending internode, the adaxial canaliculate surface densely and caducously covered with hispid trichomes; blades 14–41.8 × 6.8–15.5 cm, oblong-elliptic to oblanceolate, the base cuneate to slightly rounded or tapering to become rounded-cordate, shortly decurrent on the petiole, the margin caducously ciliate, entire to denticulate, the apex acuminate, firm-chartaceous; mature leaves adaxially glabrescent, the primary, secondary, tertiary and higher order veins glabrous; abaxial surface yellowish-green, occasionally brown to purple, glabrous, the tertiary and higher order veins with an indumentum like that of the primary and secondary veins, but sparser and shorter; 5- or 7-plinerved, including the tenuous marginals, innermost pair of secondary veins diverging from the primary vein 1.2–3 cm above the base, areolae 0.4–0.5 mm, adaxially the primary and secondary veins impressed, the tertiary and higher order veins slightly impressed to flat, abaxially the primary and secondary veins elevated and terete, the tertiary and higher order veins slightly elevated to flat. Inflorescences an erect pseudolateral interrupted verticillate spike 6.5–16.1 cm long, each verticil appearing glomerulate-fasciculate, the unbranched peduncle 1.4–5.3 cm long, borne in the axils of upper leaves, the rachis rusty-green; bracts 3–3.5 × 4.5 mm, ovate-triangular to suborbicular, with conspicuous parallel venation, rusty-translucent, glabrous adaxially except for the hispid margins, persistent in fruit; bracteoles 5–5.5 × 2–3 mm, subulate, with conspicuous parallel venation, rusty-translucent, glabrous adaxially, glabrescent abaxially, the indumentum mostly restricted to a center band, persistent in fruit. Flowers 5-merous, sessile. Hypanthia at anthesis 1.8–2 × 1 mm, free portion of hypanthium 0.8–1 mm long, subcylindric to campanulate, bluntly 10-ribbed, green, ridged on the inner surface, copiously beset with sessile rounded glands sparsely intermixed with caducous hispid trichomes like those of the general indumentum, the torus densely glandular-puberulent and scaly adaxially. Calyxopen in bud and persistent in fruit, green-brown; tube 0.5 mm long, with the same vestiture as the torus adaxially and as the hypanthium abaxially; lobes 0.5 × 0.8 mm, depressed-rounded, the margin vaguely undulate, the apex obtuse; exterior calyx teeth 0.2 mm long, inconspicuously bluntly triangular, inserted at the base of the lobes and not projecting beyond them. Petals 4–4.5 × 1.1–1.3 mm, lanceolate-triangular, the margin entire, the apex bluntly acute, translucent light green to white, adaxially sparsely papillose, abaxially glabrous, reflexed at anthesis. Stamens 10; filaments 1.6–1.8 × 0.25 mm, white-greenish, glabrous; anther thecae 1.5 × 0.3 mm, oblong-clavate, emarginate at the apex, opening by one dorsally inclined pore 0.1 mm in diameter, white to pale yellow; connective yellow, its prolongation and appendage 0.4–0.6 mm long, the appendage oblong, obtuse-rounded at the apex, copiously glandular on the edges and on both surfaces of the appendage and throughout the connective, the glands on linear to subulate stalks. Ovary 5-locular, completely inferior, ca. 1 mm long at anthesis, the apical collar 0.9 × 0.7 mm, urceolate, sparsely to moderately glandular-puberulent; style 4.5 mm long at early anthesis, parallel-sided (i.e. terete), white, glabrous; stigma truncate. Berries 3–4 × 2–2.5 mm when dry, globose, green to orange, turning white when ripe, the hypanthial indumentum persistent at maturity. Seeds 0.32–0.37 × 0.19–0.22 mm, ovoid, angled, occasionally pyramidal, brownish; lateral symmetrical plane typically ovoid, occasionally triangular, the highest point toward the chalazal side; antiraphal symmetrical plane suboblong; raphal zone suboblong, nearly as long as the seed; individual cells elongate, anticlinal boundaries channeled, undulate, with [Omega] and U-type patterns; periclinal walls convex, low-domed to nearly flat, microrelief slightly striate or absent.

    Common names: Ecuador: “hojita lanuda” (Los Ríos, Quelal 202, MO!); “chinul” (Carchi, Quelal 725, MO!).

    Habitat and Distribution: Locally common in pristine to disturbed lowland rainforests where it grows in flat sites or steep slopes in the Biogeographic Chocó region of Colombia and Ecuador , at 0–900(–1500) m.

    Phenology: Collected in flower throughout the year; in fruit from November through May, July and September.

    Etymology: The specific epithet refers to the dense rusty brown indumentum of this species.

    Taxonomy and Systematics: This species is characterized by the dense rusty-hispid indumentum throughout the plant, and the 5-plinerved leaves. The trichomes are roughened at the base but otherwise smooth, a unique character within the Octopleura clade. Its interrupted spicate-verticillate bracteate inflorescence is reminiscent of M. spiciformis, which is a much more slender plant with 5-nerved leaves, an inflorescence with a tomentose indumentum, and much smaller bracts. Phylogenetically these species belong to a well supported subclade that includes M. bractiflora, M. formicaria, and M. magnifolia . The dense indumentum at the point where the secondary veins diverge from the primary vein on abaxial foliar surfaces appears to be a domatium exploited by ants. Some ants were found in these structures.

    Conservation Status: This species would be considered Endangered EN B2ab(iii) according to IUCN criteria (AOO). A status of Vulnerable VU is warranted, because it is protected in few parts of its range. Protected in Colombia in the Farallones National Park and in the Río Escalarete Natural Reserve (Valle). In Ecuador it is protected in the Awá Indigenous Reserve (Carchi and Esmeraldas).

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