Miconia chocoensis ( Wurdack 1960: 237–238 ) 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 : 73-75

13. Miconia chocoensis ( Wurdack 1960: 237–238) Gamba & Almeda , comb. nov. Basionym : Clidemia chocoensis Wurdack. Type : COLOMBIA. Intendencia El Chocó : Bahía Solano, dense forest along Quebrada Jellita, 50–100 m, 22 February 1939, Killip & García 33520 (holotype: US!; isotypes: MO!, NY!).

Shrub with lax branches 1–3.5 m tall, bark green to brownish. Upper internodes rounded-quadrate, 1.6–4.3 cm long, cauline nodes terete, nodal line absent. Indumentum on branchlets, petioles, leaf surfaces, primary and secondary veins of young leaves adaxially, primary leaf veins abaxially, bracts, hypanthia, calyx lobes and exterior calyx teeth densely to copiously covered with white elongate slightly roughened trichomes 1.5–2.5 mm long, each

SYSTEMATICS OF THE OCTOPLEURA CLADE OF MICONIA

Phytotaxa 179 (1) © 2014 Magnolia Press 73 trichome deflexed and somewhat flattened, densely intermixed with an understory of clavate dendritic trichomes 0.1–0.15 mm long with short to moderately long thin-walled (flattened) arms. Leaves of each pair slightly to markedly anisophyllous in size; the semiterete short petioles 0.4–1.7 cm long, superficially canaliculate adaxially, the channel obscured by dense indumentum; larger blades 11.5–25.5 × 5–10 cm, smaller blades 4–15 × 2–7 cm, elliptic-obovate, the base acute-rounded, the margin entire to sinuate or entire to obscurely and distantly undulateserrulate, the apex acuminate-caudate, chartaceous; mature leaves adaxially with both the elongate and dendritic trichomes on the surface, primary and secondary veins becoming sparse to caducous with age, the tertiary and higher order veins glabrescent; abaxial surface essentially glabrous except for few glands on the venules, the secondary veins copiously covered with the dendritic trichomes, frequently intermixed with white furrowed sessile glands ca. 0.025 mm long, and with fewer resinous glands of the same type, the tertiary and higher order veins sparsely and caducously beset with the same type of glands; 5-nerved, including the tenuous marginals, areolae 0.4–0.6 mm, adaxially the primary, secondary, tertiary and higher order veins flat, abaxially the primary, secondary, tertiary and higher order veins slightly to shallowly elevated and terete. Inflorescences a congested axillary fasciculate glomerule 1–1.4 cm long, sessile, unbranched, typically paired and appearing cauliflorous on defoliated nodes; bracts (seen in field photographs) minutely subulate-triangular, rather spreading below the hypanthium, green, concealed by the dense indumentum at anthesis, early deciduous in fruit. Flowers 5-merous, sessile. Hypanthia at anthesis 3–3.3 × 2–2.9 mm, free portion of the hypanthium 1.5–1.8 mm long, suburceolate to globose, bluntly 10-ribbed, the ribs and green color obscured by the white dense indumentum, ridged on the inner surface, glabrous to somewhat scaly like the torus adaxially. Calyx open in bud and persistent in fruit, green; tube 0.35–0.45 mm long, glabrous on the inner surface and with the same vestiture as the outer hypanthial surface; lobes 1.3 × 1.2 mm, ovate, the margin entire, the apex rounded, reflexed at anthesis; exterior calyx teeth 0.5–1 mm long, subulate, inserted near the base of the calyx lobes and barely exceeding them in length. Petals 1.5–2.5 × 0.5–1 mm, oblong-ovate, the margin entire, the apex rounded-obtuse, white, glabrous on both surfaces, reflexed at anthesis. Stamens 10; filaments 1–1.2 × 0.25 mm, white, glabrous; anther thecae 0.75–1.2 × 0.38–0.45 mm, linear-oblong and widely clavate, emarginate at the apex, opening by one dorsally inclined pore 0.1–0.15 mm in diameter, pale yellow at anthesis and turning brown with age; connective darker than the thecae, its prolongation and appendage 0.3–0.5 mm long, the appendage oblong, bluntly acute to acuminate at the apex, densely and conspicuously glandular, the glands sessile or short-stalked and rounded, denser on the appendage and becoming fewer toward the connective apex. Ovary 5-locular, 1/2 to 2/3 inferior, 1.7–1.9 mm long at anthesis, the apical collar absent, the apex 0.2–0.3 mm in diameter, conic to somewhat truncate with a slightly raised perimeter, densely covered with minute sessile glands; style 2.9–3.1 mm long, parallel-sided (i.e. terete), white, glabrous; stigma truncate when dry. Berries 2–2.5 × 2.9–3.2 mm when dry, globose-oblate, green-yellow becoming bright orange when ripe, the hypanthium indumentum persistent at maturity. Seeds 0.48–0.53 × 0.28–0.31 mm, pyramidal, brown; lateral symmetrical plane triangular, the highest point near the central part of the seed, with a foot-like projection at the micropylar end; antiraphal symmetrical plane suboblong; raphal zone suboblong, ca. 80 % the length of the seed; multicellular sculpture rugose throughout the seed; individual cells elongate, anticlinal boundaries somewhat channeled, undulate, with Ω- and U-type patterns, others raised, more or less straight; periclinal walls convex, low-domed to nearly flat, others concave, microrelief striate.

Additional specimens studied:— COLOMBIA. Chocó: (Nuquí), Coquí, Quebrada Trapiche al sureste de Coquí, 5°32’N, 77°15’W, 100–160 m, February 1994, Galeano et al. 5565 ( COL, US) ; Río Pavasa, near Espejo waterfalls, 50–100 m, 18 May 1974, Warner 259 ( MO); ( Bahía Solano ) , Ciudad Mutis, Jardín Botánico del Pacífico, Cerro Palo on trail to cell phone antenna (on Cerro Mecana ), 6.248°N, - 77.35°W, 8 February 2012, Almeda et al. 10473 ( CAS, CHOCO, COL) . Risaralda: (Mistrató), Puerto de Oro, Chirrincha , Margen izquierdo del Río Aguita , 950 m, 11 April 1991, Franco et al. 3581 ( US) . ECUADOR. Carchi: Nside of Río Mira, across from Lita, Steep N-facing slope directly across from ( S of) community of Barboso , on Sside of Río Barboso , Transect 750-2, 0°53’N, 78°27’W, 750 m, 11 August 1994, Boyle & Boyle 3565 ( MO) ; Property of Humberto Rosero, on Nside of Río Mira, Just above cable crossing upstream from Lita and downstream from Cachaco , On steep W-facing slope, 0°52’N, 78°2’6"W, 760–780 m, 20 August 1994, Boyle et al. 3652 ( MO) . Esmeraldas: Road Lita-Alto Tambo-San Lorenzo, km 6.9 from Lita, Wet forest by river on side of road, 0°52’24.6"N, 78°29’33.2"W, 720 m, 30 September 2001, Cotton et al. 1794 ( CAS, MO, QCA) .

Illustration:— None found.

Common names and documented uses:— None recorded.

74 Phytotaxa 179 (1) © 2014 Magnolia Press

GAMBA & ALMEDA

Habitat, distribution and ecology: — Miconia chocoensis is known from primary rain or premontane forest understory, commonly close to streams or rivers in the Biogeographic Chocó, from Colombia to Ecuador ( Fig. 12 ), at 50–950 m. It has been poorly collected but is probably not uncommon. Prior to this study it had not been reported from Ecuador where it occurs at 720–780 m.

Phenology:— Collected in flower and fruit in February; in fruit in May, and from August to September.

Etymology:— The specific epithet refers to the type locality of the species: the department of Chocó in Colombia.

Discussion:— Miconia chocoensis has distinct white lanate vegetative and floral indumentum, congested fasciculate glomerules of sessile flowers, fugacious or concealed bracts, and consistently 5-merous flowers. It is most similar, and probably sister to M. quadridomius with which it has been confused, and shares similar denselanate pubescence and inflorescence architecture (sessile congested fasciculate glomerules). In M. quadridomius the indumentum is rather ferrugineous. On the other hand, in M. quadridomius the leaves are strikingly 5-(7-) plinerved (vs. 5-nerved), with the possibly tufted-trichome domatia lacking in M. chocoensis , the bracts are persistent and rather conspicuous, and the flowers are consistently 4-merous. Within the Approximata subclade, both belong to a group of closely related species along with M. approximata and M. veraguensis , all of which share a similar clavate-furfuraceous vegetative indumentum (at least in the understory), sessile inflorescences, conspicuously reflexed ovate-triangular to subulate calyx lobes at anthesis, bright orange berries at maturity, and pyramidal rugulose seeds.

Miconia chocoensis is reported here from Ecuador for the first time. It was thought to be endemic in Colombia. The Ecuadorian material was erroneously identified as M. quadridomius , which is understandable because the two species are easily confused for the reasons mentioned above. However, these specimens (Boyle 3565 MO!, 3652, MO!, and Cotton 1794 CAS!, MO!), have clearly 5-merous flowers, longer indumentum and the leaves are 5-nerved.

Conservation status:— Endangered EN B2ab(iii). In Colombia it is only protected in the Jardín Botánico del Pacífico (Chocó).

Figures

FIGURE 12. Distributions of Miconia anchicayensis and M. chocoensis, M. approximata, M. atropurpurea, M. aurantiaca and M. aff. aurantiaca.