Miconia incerta ( Wurdack 1978a: 302–303 ) Gamba & Almeda 2014

Gamba, Diana & Almeda, Frank, 2014, Systematics of the Octopleura Clade of Miconia (Melastomataceae: Miconieae) in Tropical America, Phytotaxa 179 (1), pp. 1-174 : 82-83

17. Miconia incerta ( Wurdack 1978a: 302–303) Gamba & Almeda , comb. nov. Basionym: Ossaea incerta Wurdack. Type: ECUADOR. Prov. Imbabura: Lita , 501 m, 25 April 1949, Acosta-Solís 12274 (holotype: F!).

Small shrub 1–1.5 m tall, laxly and weakly branched. Upper internodes quadrisulcate, 2.9–7.4 cm long, cauline nodes terete, nodal line absent. Indumentum on branchlets, primary and secondary leaf veins abaxially, inflorescence axes, and pedicels densely to moderately composed of translucent-yellowish dendritic trichomes 0.05–0.1 mm long with short axes and few-moderate number of terete arms. Leaves of a pair isophyllous; sessile; blades (2.7–)5.5–15 × (1.1–) 1.9–9.8 cm, ovate to lanceolate, the base cordate and amplexicaul, the margin crenateserrate, the apex bluntly acuminate, chartaceous; mature leaves adaxially soon glabrous, at first sparsely covered with the general dendritic trichomes, the primary, secondary, tertiary and higher order veins glabrous; the abaxial surface glabrescent with a sparse resinous indumentum of slightly furrowed more or less stalked glands 0.04–0.05 mm long, the same type of glands sparsely present on the secondary, tertiary and higher order veins abaxially; 5-7- nerved, including the tenuous marginals, areolae 0.4–0.5 mm, adaxially the primary and secondary veins slightly impressed, the tertiary and higher order veins flat, abaxially the primary and secondary veins elevated and terete, the primary vein canaliculate, the tertiary and higher order veins slightly elevated. Inflorescences an axillary fewflowered thyrsoid 8–11 cm long, including a thin reddish peduncle 3–4 cm long, pendant and laxly divaricate from the peduncle apex, paired on the upper and lateral leaves; bracts 0.25–0.35 × 0.15–0.2 mm, subulate-linear, erect, glabrous, persistent in fruit; bracteoles 0.2–0.3 × 0.1–0.2 mm, linear, somewhat spreading, glabrous, persistent in fruit. Flowers (4-)5-merous on thin pedicels 1–1.5 mm long. Hypanthia at anthesis 2.7–2.9 × 2 mm, free portion of hypanthium 0.8–1.2(–1.5) mm long, campanulate to subcylindric, bluntly (8-)10-ribbed, copiously resinousglandular with slightly furrowed more or less stalked glands 0.05–0.1 mm long, occasionally intermixed with caducous dendritic trichomes, ridged on the inner surface, glabrous like the torus adaxially. Calyx open in bud and persistent in fruit; tube 0.2 mm long, glabrous inside, resinous-glandular like the hypanthium; lobes (0.5–)0.6–0.8 × 0.3–0.5 mm, broadly and bluntly triangular, the margin vaguely undulate, the apex rounded, adaxially glabrous, abaxially moderately resinous-glandular; exterior calyx teeth 1.3–1.5 mm long, linear-subulate, inserted on the apical half of the calyx lobes and projecting beyond them, copiously resinous-glandular. Petals 6–6.3 × 0.75 mm, lanceolate, the margin entire, the apex bluntly acute to acuminate, greenish to white, glabrous on both surfaces, reflexed at anthesis. Stamens 10; filaments 1.5–2.5 × 0.25 mm, white, glabrous; anther thecae 1.9–2.5 × 0.3–0.35 mm, linear-oblong and subulate, truncate-acuminate at the apex, opening by one dorsally inclined pore 0.1 mm in diameter; connective slightly darker than the thecae, its prolongation and appendage 0.6–0.75 mm long, the appendage lanceolate, acute at the apex, minutely and copiously glandular, the glands rounded and sessile. Ovary (4-)5-locular, 9/10 inferior, 2.2–2.4 mm long at anthesis, the apical collar 0.2–0.3 × 0.2–0.25 mm, conic-depressed, with a corona of ca. 10 resinous-glandular setulae; style not seen at anthesis, parallel sided (i.e. terete), white, glabrous; stigma truncate when dry. Berries 3.5–4 × 2 mm when dry, globose, red when ripe, the hypanthial indumentum somewhat persistent at maturity. Seeds 0.33–0.37 × 0.27–0.3 mm, ovoid, not angled, dark-brown; lateral and antiraphal symmetrical planes ovate, the highest point near the central part of the seed; raphal zone ovate to suboblong, ca. 80% the length of the seed, ventrally expanded toward the micropyle; multicellular sculpture rugose throughout the seed; individual cells elongate, anticlinal boundaries channeled, somewhat undulate to irregularly curved; periclinal walls convex, low to high-domed, microrelief striate.

Additional specimens studied:— COLOMBIA. Antioquia: (Frontino), Nutibara, Cuenca alta del Río Cuevas , carretera a la Blanquita, 1350 m, 18 July 1987, Sánchez et al. 1485 ( HUA, US) . Chocó: Carretera Tutunendo-El Carmen , Entre kms 135 y 120, Alto Río Atrato , Orilla de la carretera, 800–1200 m, 29 April 1979, Forero et al. 6148 ( COL, MO); ( San José del Palmar ) , escuela antigua de Galapagos, cascadas al final de la trocha de la escuela, 1300 m, 20 February 2011, Mendoza 17636 ( FMB) . Valle: Río El Chanco, márgen izquierda, camino que conduce a Aguabonita , subiendo hacia la cabecera del Río El Chanco , 400 m, 3 April 1985, Ruiz et al. 111 ( COL, CUVC) . ECUADOR. Esmeraldas: (Quininde), Bilsa Biological Station, Montañas de Mache , 35 km Wof Quininde, 5 km Wof Sta Isabela, 0°21'N, 79°44'W, 400–600 m, 30 December 1994, Pitman & Marsh 1130 ( MO) .

Illustration:— None found.

Common names and documented uses:— None recorded.

Habitat, distribution and ecology:— Rare in primary wet forests, also in disturbed sites, on the Pacific Andean slope of Colombia and Ecuador ( Fig. 14 ), at 400–1350 m.

Phenology:— Collected in bud in July. In flower and fruit in April and December.

82 Phytotaxa 179 (1) © 2014 Magnolia Press

GAMBA & ALMEDA

Etymology:— The specific epithet is derived from the Latin word incert (= uncertain), probably referring to the rarity of this species or its uncertain affinities.

Discussion:— The style description is based on the protologue and Flora of Ecuador treatment ( Wurdack 1980), because this floral part was missing on the few specimens available for study.

Miconia incerta has distinctive sessile, amplexicaul ovate-lanceolate leaves, and a copiously resinousglandular hypanthium. Morphologically it is very similar to M. bensparrei and M. palenquensis especially with respect to the asperous vegetative indumentum, which in M. incerta is somewhat yellowish-translucent (vs. brownish), and in the sessile-amplexicaul leaves, which are very distinct in shape (ovate-lanceolate vs. elliptic or elliptic-obovate); the inflorescence architecture is also somewhat comparable, although less elaborated in M. incerta (thyrsoid vs. dithyrsoid). On the other hand, the hypanthial indumentum and anther morphology is clearly distinct, as well as the seed shape and micromorphology of the testa. The latter characters make it difficult to assess the systematic position of this species among described species in the Octopleura clade. In M. incerta , the multicellular seed sculpture (rugose) and its microrelief (striate) are similar to those found in the species of the Approximata subclade. However, other vegetative characters (complete lack of anisophylly, inflorescence architecture) and floral features (anther morphology) seem to negate any likely affinities to species of the Approximata subclade. Wurdack described the petals as ovate based on rehydrated buds, but they are actually lanceolate and similar to those in M. variabilis , which he considered close to M. incerta . Phylogenetically M. variabilis has a basal position among species of the Variabilis subclade, so they would be definitely be closely related if M. incerta is ultimately shown to belong to this subclade as well. Wurdack (1978a) also compared M. incerta with M. albertobrenesii but these two species are unquestionably distinct and not readily confused.

Conservation status:— Endangered EN B2ab(iii). Habitat destruction is the only known threat. This species was thought to be endemic to western Ecuador (but here it is reported from Colombia as well), where it is known from two collections (in Esmeraldas and Imbabura provinces). Discovered in 1949 near Lita and rediscovered in 1994 in the Bilsa private reserve, in the Reserva Ecológica Mache-Chindul (Esmeraldas). It may also occur in the Reserva Ecológica Cotacachi-Cayapas ( Cotton & Pitman 2004).

Figures

FIGURE 14. Distributions of Miconia erikasplundii and M. incerta, M. evanescens, M. formicaria and M. rufibarbis, and M. latidecurrens.