Miconia radicans (Cogn.) Gamba & Almeda

  • Family

    Melastomataceae (Magnoliophyta)

  • Scientific Name

    Miconia radicans (Cogn.) Gamba & Almeda

  • Primary Citation

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

  • Basionym

    Clidemia radicans Cogn.

  • 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: COSTA RICA. Comarca de Limón, Llanos de Santa Clara, Río Jiménez, 650 ft, 11 April 1894, Donnell Smith 4789 (isotypes: BR-2 sheets-internet images!, US-internet image!).

    Description: Suffrutescent herb or subshrub 0.2–1 m tall, occasionally rupicolous, suberect and sparingly branched. Upper internodes (1.6–3.8 cm long) and cauline nodes terete, nodal line present as a moderate ridge. Indumentum on branchlets, petioles, adaxial surface of young leaves, primary, secondary, tertiary and higher order veins abaxially, inflorescence axes, bracts, bracteoles, pedicels, hypanthia, calyx lobes abaxially, and exterior calyx teeth densely to moderately covered with brownish-translucent sessile-stellate trichomes 0.35–0.45 in diameter, superficially appearing simple. Leaves of each pair strongly dimorphic (1:6–8); the semiterete petioles 0.1–0.8 cm long, narrowly canaliculate adaxially, the channel obscured by the dense indumentum; larger blades 8.5–20 × 3–7.7(–9) cm, elliptic-oblong and somewhat falcate, the base obtuse to rounded and slightly oblique, the margin entire, the apex bluntly acute to rounded; smaller blades 1.5–2.7 × 0.9–4 cm, ovate to ovate-elliptic or subrotund, the base obtuse to cordate, the margin entire, the apex acute to short-acuminate; firm-membranaceous; mature leaves adaxially occasionally flushed red-purple on the surface and primary vein, glabrate, the primary, secondary, tertiary and higher order veins glabrous; abaxial surface glabrate; 3- or 5-nerved, including the tenuous marginals, with a moderate thick-callose vesicular structure at the base of the leaves abaxially where the innermost pair of secondary veins diverge from the primary vein (domatia?), areolae 1–2 mm, adaxially the primary, secondary, tertiary and higher order veins flat, abaxially the primary and secondary veins elevated and terete, the tertiary and higher order veins flat. Inflorescences an axillary few-flowered thyrsoid or dithyrsoid 3.5–8.3 cm long, typically including a peduncle 1.5–2.6 cm long, rarely sessile, somewhat divaricately branched from the peduncle apex, when sessile openly bifurcate from the base, solitary or paired in the axils of the smaller leaves at the upper nodes, the rachis pink-reddish to brown; bracts and bracteoles 0.3–0.5 × 0.5 mm, narrowly triangular, somewhat spreading, persistent to tardily deciduous in fruit. Flowers 4-merous on pedicels (0.3–)0.5–1 mm long. Hypanthia at anthesis 2.6–2.75 × 1–1.5 mm, free portion of hypanthium 1 mm long, urceolate, constricted distally into a subcylindric neck, bluntly 8-ribbed, reddish, the indumentum sparse, ridged on the inner surface, glabrous, the torus adaxially sparsely glandular-puberulent becoming glabrous, the glands stalked or subsessile and rounded. Calyx open in bud and persistent in fruit, pink-red; tube 0.19–0.27 mm long, abaxially with the same vestiture as the hypanthium, adaxially minutely and sparsely glandular; lobes 0.3–0.5 × 1 mm, ovate, the margin entire, the apex rounded, adaxially glabrescent with a few papillae; exterior calyx teeth 0.29–0.34 mm long, bluntly triangular to subulate, callose, inserted at the base of the lobes and not projecting beyond them. Petals 1.5–2 × 1.4–1.5 mm, obovate, the margin entire, the apex rounded-obtuse to somewhat truncate, white, copiously and minutely papillose on both surfaces, slightly spreading to erect at anthesis. Stamens 8; filaments 1.5–2 × ca. 0.22 mm, white, glabrous; anther thecae 2 × 0.25–0.29 mm, linear-oblong, obtuse-emarginate at the apex, opening by one dorsally inclined pore 0.1 mm in diameter, cream to yellow; connective yellow, its prolongation and appendage 0.2–0.4(–0.5) mm long, the appendage oblong, obtuse at the apex, copiously gland-edged, the glands minute and rounded, mostly sessile, sparsely distributed throughout the connective. Ovary 4-locular, completely inferior, 1.6–1.75 mm long at anthesis, the apical collar absent, the apex 0.15 mm in diameter, somewhat depressed, glabrous to inconspicuously glandular-puberulent; style 4–4.5 mm long, tapering distally, glabrous; stigma truncate to expanded-truncate. Berries 3.8–4.2 × 4–5 mm when dry, globose-oblate, bright pink ripening bright blue, the hypanthial indumentum early caducous at maturity. Seeds 0.33–0.38 × 0.14–0.16 mm, ovoid, angled, light brown; lateral and antiraphal symmetrical planes ovate, the highest point toward the chalazal side or near the central part of the seed; raphal zone suboblong, nearly as long as the corpus of the seed, extending along its entire length, ventrally and longitudinally expanded, dark brown; individual cells elongate, anticlinal boundaries moderately channeled, undulate, with [Omega] and U-type patterns; periclinal walls convex, low-domed to nearly flat, microrelief punctate.

    Common names: Ecuador: “blueberry” (Vrieze et al. 4312, NY!).

    Habitat and Distribution: Rare to common, usually found on steep riparian rocky banks in rain forests and cloud forests, from Nicaragua south through southern Central America to Colombia and Ecuador , at (12–)100–1450 m. In Nicaragua it is only known from the former department of Zelaya. It is more common throughout Costa Rica and Panama. In Colombia it has only been collected in Chocó; in Ecuador it is known from the Pacific Andean slope.

    Phenology: Collected in flower from December through October; in fruit throughout the year.

    Etymology: The specific epithet comes from the Latin radic (= a root), and might refer to the numerous aerial roots on the type specimens.

    Taxonomy and Systematics: This species is distinguished by its prevailingly rupicolous habit, pronounced foliar dimorphism, and dense sessile-stellate indumentum. These features are also present in its closest relative M. biolleyana, but in M. radicans the foliar dimorphism is more striking (1:6–8 vs. 1:2), and the blade shape is different (elliptic-oblong and falcate vs. broadly ovate to subrotund). The inflorescences, although architecturally similar are fewer flowered in M. radicans than they are in M. biolleyana. The thickened callose structure produced at the abaxial foliar base might be an acarodomatium, although it is less prominent than in M. biolleyana and no insects or eggs of any kind where found in the specimens studied. This domatium appears to be both taxonomically and phylogenetically significant since it is present in the trio of closely related species including M. biolleyana, M. erikasplundii, and M. radicans.

    Conservation Status: This species would be considered Endangered EN B2ab(iii) based on IUCN criteria (AOO). However, because it occurs in many protected zones, a status of Least Concern LC is justified. In Colombia it is protected in Farallones National Park (Valle). In Costa Rica it is protected in the San Ramón Forest Reserve and in the Monteverde Biological Reserve (Alajuela); in the Barbilla and La Amistad National Parks (Limón); in the Golfo Dulce Forest Reserve and the Golfito Wild Life Reserve (Puntarenas); in the Cerro Nara Portected Zone. In Ecuador it is protected in the Mache-Chindul Ecological Reserve (Esmeraldas); and in the Río Palenque Biological Station (Los Ríos). Protected in Panama in Darién National Park (Darién).

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