Miconia evanescens Gamba & Almeda 2014, comb. nov.
Creators: name: Gamba, Diana
name: Almeda, Frank
Publisher: name: Zenodo
Year: 2014
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Myrtales
Melastomataceae
Miconia
Miconia evanescens

description: 15. Miconia evanescens (Almeda 2004: 98–101) Gamba & Almeda, comb. nov. Basionym: Clidemia evanescens Almeda. Type: PANAMA. Coclé Prov.: Forested slopes above El Cope along abandoned road leading to the Continental Divide, 700–850 m, 25 February 1988, Almedaet al. 5933 (holotype: CAS!; isotypes: INB-internet image!, MO!, NY!, PMA-internet image!, US-internet image!).   
 Subshrub or shrub 0.5–4 m tall, occasionally forming thickets, scraggly branched, the branches often pendant, bark red-purple to brown. Upper internodes [(1–) 2–2.9 cm long] and cauline nodes terete, nodal line absent.   
 76 Phytotaxa 179 (1) © 2014 Magnolia Press   
GAMBA & ALMEDA  
 Indumentum on branchlets, petioles, adaxial surface of young leaves, primary, secondary, tertiary leaf veins abaxially, inflorescence axes, bracts, bracteoles, pedicels, hypanthia, calyx lobes, and exterior calyx teeth copiously to moderately covered with whitish dendritic trichomes 0.1–0.15 mm long with short to moderately long thinwalled (flattened) arms, each trichome clavate and somewhat thickened. Leaves of each pair somewhat anisophyllous in size at maturity, one leaf of a pair commonly early deciduous, the phyllotaxy thus appearing pseudoalternate; the semiterete petioles 1.5–4.7 cm long, adaxially canaliculate, green-brownish; larger blades (8.5–)13–28 × (5–) 6–14 cm, smaller leaves 4–12.2 × 2–4.8 cm, elliptic to elliptic-ovate, the base obtuse to rounded, the margin entire to slightly sinuate, the apex acuminate to caudate, chartaceous; mature leaves adaxially glabrescent, the primary, secondary, tertiary and higher order veins glabrous; abaxial surface along with the tertiary and higher order veins copiously beset with minute resinous sessile to short-stalked glands ca. 0.05 mm long with thin-walled short heads; 5- or 7-nerved, including the tenuous marginals, areolae 0.2–0.25 mm, adaxially the primary and secondary veins impressed, the tertiary and higher order veins flat, abaxially the primary and secondary veins elevated and terete, the tertiary and higher order veins slightly elevated to flat. Inflorescences typically an axillary cluster of dichasia, or terminal with both lateral buds at a node elongating and overtopping the inflorescence (pseudolateral), 1–2.5(–4.7) cm long, sessile, typically poorly branched with multiple axes arising from a common point (fascicle-like) at the base, occasionally appearing as a short and multiflorous thyrsoid, commonly paired, the rachis light green; bracts and bracteoles 1.5–3 × 1–2 mm, triangular, thick, spreading, persistent in fruit. Flowers 4-(5-) merous on pedicels 0.5–1 mm long. Hypanthia at anthesis 3.1–3.5 × 1–1.2 mm, completely free but tightly enveloping the ovary, subcylindric to campanulate, bluntly 8-ribbed, light green, ridged on the inner surface, along with the torus adaxially densely and minutely glandular, the glands sessile and rounded. Calyx open in bud and persistent in fruit, light green; tube obsolete; lobes 1.5–2.5 × 1–1.5 mm, oblong-triangular, the margin entire, the apex bluntly acute, brownish at the margin, reflexed at anthesis; calyx teeth 0.5–1.2 mm long, subulate, inserted at the apical half of the calyx lobes and spreading beyond them. Petals 1.5–2 × 0.5–1 mm, obovate-oblong, the margin entire, the apex rounded-obtuse to slightly emarginate, white to translucent white, glabrous on both surfaces, reflexed at anthesis and early deciduous. Stamens 8; filaments 1.5 × 0.25 mm, white, glabrous; anther thecae 1.5 × 0.5 mm, linear-oblong, more or less truncate to somewhat emarginate at the apex, opening by one dorsally inclined pore 0.1–0.2 mm in diameter, yellow or white; connective white, its prolongation and appendage 0.5 mm long, the appendage oblong-lanceolate, bluntly acute to obtuse at the apex, copiously glandedged with short-stalked glands to 0.15 mm long with thin-walled short heads. Ovary 4-locular, completely superior but tightly enveloped by the hypanthium, ca. 2.5 mm long at anthesis, the apical collar 0.4–0.5 × 0.2–0.25 mm, conic, copiously glandular-puberulent; style 6 mm long, narrowed distally (i.e. tapering), white, glabrous; stigma truncate to capitellate. Berries 6 × 6 mm when dry, globose, green, then bright orange to reddish when ripe, the hypanthial indumentum persistent at maturity. Seeds 0.54–0.62 × 0.27–0.33 mm, pyramidal, brown; lateral symmetrical plane triangular, the highest point toward the chalazal side, with a foot-like projection at the chalazal end; antiraphal symmetrical plane suboblong; raphal zone circular to suboblong, ca. 50–60% the length of the seed; multicellular sculpture rugose throughout the seed; individual cells elongate, anticlinal boundaries channeled or raised, irregularly curved; periclinal walls convex, low-domed to nearly flat, microrelief striate. Chromosome number: n=17.   
 Additional specimens studied:— COLOMBIA. Cauca: (Isla Gorgona), 152 m, 7 October 1924, “St. George” Expedition 526 (F). Chocó: Nridge of Alto Buey, premontane rain forest, E-SW of El Valle, 500–1150 m, 8 August 1976, Gentry & Fallen 17363 (US). Nariño: R.N. La Planada, 7 km above Chucunes (along road between Tuquerres and Ricaurte) along trail to El Hondón, beginning at Quebrada Tejón and for 0.5 km beyond, 1°8’N, 77°54’W, 780–800 m, 15 March 1990, Croat 71473 (MO, US); La Planada B.R., ca. 7 km Sof Chucunes, along trail to Pialapi beyond Quebrada La Calledita, 1°10’N, 77°55’W, 1800–1900 m, 8 August 1990, Luteyn & Sylva 13943 (CAS); La Planada B.R., 7 km above Chucunes on road between Tuquerres and Ricaurte, above “La Posada” building, 1780 m, 27 July 1988, Croat 69609 (US); Trail from la Planada to Pielapi, 1°4’N, 78°2’W, 1600–1800 m, 22 July 1988, Gentry et al. 63589 (US); La Planada, Trail to El Hondón, 6–12 km SW of La Planada, 1°4’N, 78°2’W, 1750–1800 m, 5 January 1988, Gentry et al. 60383 (US); La Planada B.R., Near Ricaurte, 1°5’N, 78°1’W, 1800 m, 21 December 1987, Gentry et al. 59678 (US); La Planada, Sof Ricaurte, 7 km from Tumaco-Pasto road, 1°10’N, 77°158’W, 1800 m, 25 July 1986, Gentry et al. 55120 (MO, US); La Planada B.R., 7 km from Chucunes, 1°5’N, 78°1’W, 1800 m, 3 January 1988, Gentry & Keating 60310 (US); Trail to El Hondón, 5–12 km SW of La Planada, 1°4’N, 78°2’W, 1750–1800 m, 6 January 1988, Gentry et al. 60490 (US); (Barbacoas),   
 SYSTEMATICS OF THE OCTOPLEURA CLADE OF MICONIA   
 Phytotaxa 179 (1) © 2014 Magnolia Press 77 Altaquer, El Barro, El Barro, 1300 m, 1 March 1995, Fernández et al. 12391 (COL, MO); R.N. La Planada, 7 km above Chucunes (on road between Tuquerres and Ricaurte), along Sendero Vieja, along ridge top in direction of La Pina, 1°6’N, 77°54’W, 1950–2010 m, 9 March 1990, Croat 71210 (MO); La Planada B.R., ca. 7 km Sof Chucunes, along trail opposite the posada, 1°10’N, 77°55’W, 1800–1900 m, 9 August 1990, Luteyn & Sylva 13974 (CAS).   
 Risaralda: (Mistrató), Jeguadas, bosque primario poco perturbado a la orilla del camino, Cordillera Occidental, vertiente occidental, 5°26’N, 76°02’W, 1500 m, 28 March–2 April 1992, Betancur et al. 3252 (US). Valle: (Dagua), Corregimiento Queremal, P.N.N. Farallones, Sector Alto Anchicayá, Sendero de la quebrada La Riqueza, 3°36.081’N, 76°53.758’W, 910 m, 10 January 2013, Alvear et al. 1553 (CAS, COL). COSTA RICA. Alajuela: (Upala), Bijagua, El Pilón, Subiendo por la margen derecha del Río El Roble hasta el Volcán Tenorio, 10°41’N, 85°0’20"W, 1000–1400 m, 9 July 1988, Herrera et al. 2037 (CAS, CR); (Guatuso), P.N. Volcán Tenorio, Cuenca del Río Frío, Estación El Pilón, Sendero hacia Cerro Montezuma, 10°42’0"N, 85°0’0"W, 800 m, 14 January 2010, Kriebel et al. 5490 (INB, NY); R.B. Monteverde, Río Peñas Blancas, Finca de Jesús Rojas, 10°18’N, 84°44’W, 850–900 m, 4 December 1989, Bello 1540 (CAS, CR, MO); (San Ramón), No protegida, Cuenca del San carlos, Curso de Plantas, Al lado del sendero Zaíno, 10°13’0"N, 84°35’20"W, 800–900 m, 11 August 2002, Kriebel 939 (INB, MO). Heredia: (Sarapiquí), Horquetas de Sarapiquí, R.Rara Avis, Sendero Guácimo, 10°17’3"N, 84°2’47"W, 700 m, 23 July 1995, Martén 971 (CR, F, MO); Río Sarapiquí above Cariblanco, 15 September 1965, Schnell 99 (CR, F). ECUADOR. Carchi: Trail along ridge and forest slope to NW of Awá encampment, Gualpi Chico area near Rodriguez finca, 0°58’N, 78°16’W, 1258–1323 m, 19 January 1988, Hoover et al. 3323 (US); (Tulcán), R. Étnica Awá-Camumbi, 0°53’N, 78°16’W, 1700–1900 m, 20 July 1991, Quelal et al. 164 (MO, QCNE); (Espejo), R. Golondrinas, El Corazón, recorrido por el sendero a La Cortadera hasta El Mirador, 2390 m, 23 January 2004, Vargas et al. 4362 (CAS). Esmeraldas: (Quininde), Estación Biológica Bilsa, Carretera Herrera- El Páramo (Sta. Isabel), 0°4’N, 79°5’W, 580 m, 18 February 1995, Palacios et al. 13507 (MO); (San Lorenzo), Ricaurte, R. Indígena Awá, 1°10’N, 78°32’W, 300 m, 19–24 October 1992, Tipaz et al. 2095 (US); R.B. Bilsa, Sendero Amarillo, 0°20’49"N, 79°42’41"W, 540 m, 13 February 2009, Stern & Tepe 397 (NY). PANAMA. Chiriquí: Edwin Fabrega Dam and R. in Fortuna, Along trail to hydrological station along Río Hornito below forestry house along the road, 8°45’N, 82°5’W, 1150–1200 m, 20 January 1989, Almeda et al. 6348 (CAS, PMA); (Gualaca-Chiriquí Grande), 4.8 mi beyond IRHE facilities at Dam, 4 mi Nof bridge over Bayano Lake, along gravel road which turns off main highway, 100 m beyond pipeline marker 108, 8°46’"N, 82°16’"W, 23 September 1987, Croat 68018 (CAS); Fortuna Dam Project area, Slope NW of confluence of Río Hornito and Río Chiriquí, 8°44’N, 82°13’W, 1050–1100 m, 11 November 1980, Sytsma & Stevens 2260 (CAS); Fortuna Dam area, To Nof reservoir near Quebrada Bonito, 8°45’N, 82°13’W, 1100 m, 30 July 1984, Churchill 5787 (CAS); Edwin Fabrega Dam and R. in Fortuna, Quebrada Arena, the first creek Sof the Continental Divide on the road to Chiriquí Grande, 8°45’N, 82°5’W, ca. 1075 m, 15 January 1989, Almedaet al. 6217 (CAS). Coclé: Omar Torrijos N.P., About 7–10.5 km beyond El Copé in Omar Torrijos N.P, along end of the rocky trail to Río Blanco and Limón beyond Alto Calvario, 770–870 m, 21 February 1996, Almedaet al. 7660 (CAS, PMA); Alto Calvario, Above El Copé, ca 6 km Nof El Copé, Atlantic slope, along trail through forest W off old lumber trail which leads down to Las Ricas, Limón and San Juan., 89°39’N, 80°36’W, 23 June 1988, Croat 68793 (CAS); (El Copé), División continental arriba de Barrigón y el aserradero viejo, Camino de caballo a Coclesito, 8°40’N, 80°36’W, 880 m, 27 April 1992, Peña et al. 469 (CAS, F, PMA); (El Copé), División continental arriba de Barrigón y el aserradero viejo, Camino decaballoa Coclesito, 8°40’N, 80°36’W, 880 m, 27 April 1992, Peñaet al. 469 (CAS, PMA); Alongcontinental divide above El Cope, 8°38’N, 80°35’W, 850 m, 7 April 1988, McPherson 12417 (MO); Forested slopes above El Copé along abandoned road leading to the Continental Divide, 8°38’N, 80°38’W, 700–850 m, 24 January 1989, Almedaet al. 6386 (BM, CAS, INB, MEXU, MO, PMA). Comarca de San Blas: Cerro Brewster, 9°18’N, 79°16’W, 800–850 m, 20 November 1985, de Nevers et al. 6273 (CAS); Cerro Brewster, 9°18’N, 79°16’W, 850 m, 21 April 1985, de Nevers et al. 5452 (CAS); Cerro Habú, Vicinity of peak, 9°23’N, 78°49’W, 762 m, 19 December 1980, Sytsma et al. 2694 (CAS); Cerro Habú, Vicinity of peak, 9°23’N, 78°49’W, 762 m, 19 December 1980, Sytsma et al. 2717 (CAS). Veraguas: Along trail to summit of Cerro Tute about 1/ 2 mile above the Escuela Agricultura Alto Piedra near Santa Fe, 900–1100 m, 29 January 1989, Almedaet al. 6490 (CAS, PMA); Trail to R.B, Serrania de Tute and the summit of Cerro Tute, about 0.7 km beyond the Escuela Agrícola Río Piedra just outside Santa Fe, 860–1300 m, 18 February 1996, Almedaet al. 7613 (CAS, PMA).   
 Illustration:— Almeda 2004: 100, fig. 4.   
 Common names and documented uses:— None recorded.   
 78 Phytotaxa 179 (1) © 2014 Magnolia Press   
GAMBA & ALMEDA  
 Habitat, distribution and ecology:— Locally common in primary and secondary rain forests and cloud forests from north-central Costa Rica disjunctly to western Panama, southwestern Colombia, and northwestern Ecuador (Fig. 14), at 150–2010 m. In Colombia it is known from the western slope of the western Andean cordillera in Chocó, Risaralda, and Valle, and disjunctly in the southern Pacific in the Planada Natural Reserve, Barbacoas and Isla Gorgona. In this study several specimens of this species were newly identified from Ecuador (Carchi and Esmeraldas).   
 Phenology:— Collected in flower from January through April, July through October and December; in fruit from June through April.   
 Etymology:— The specific epithet, meaning quickly disappearing or fading, refers to the fugacious petals at anthesis.   
 Discussion:— Among its closer relatives and within the Octopleura clade, M. evanescens is the only species consistently characterized by a completely superior ovary that is tightly enveloped but completely free from the hypanthium. It is also distinct in its whitish thickened furfuraceous indumentum of dendritic trichomes and the pseudo-alternate foliar arrangement. The anisophylly in this species when present is pronounced but is not constant in all the pairs of mature leaves. The mature leaves at some nodes are isophyllous with measurements comparable to those of the larger leaves. Along with M. approximata, it has a glandular-puberulent apical ovary collar, and the foliar venules abaxially are copiously beset with a resinous indumentum of minute sessile to short-stalked glands with thin-walled short heads, but it differs from this taxon in the characters mentioned under the discussion of M. approximata. Phylogenetically, M. evanescens is sister to M. aurantiaca, with similar inflorescence architecture, but different in floral and indumentum characters (see M. aurantica discussion).   
 SYSTEMATICS OF THE OCTOPLEURA CLADE OF MICONIA   
 Phytotaxa 179 (1) © 2014 Magnolia Press 79   
The inflorescence branching is often poorly developed, but this character is variable and sometimes the inflorescence appears thyrsoid and rather short and dense. The more developed inflorescences which appear to be restricted to South American material are commonly associated with larger leaves; these occur within the normal elevational range for the species.  
 Acollection from Carchi, Ecuador, (Vargas et al. 4362), is indistinguishable from M. evanescens, but the hypanthium is densely resinous-glandular (vs. furfuraceous in M. evanescens), with the same type of glands that are produced on the abaxial leaf venules. This specimen was collected in a high montane forest, at 2390 m, higher than where M. evanescens normally occurs, so it might represent an elevational variant.   
 Conservation status:— This species would be considered Endangered EN B2ab(iii) based on IUCN criteria (AOO). However, it occurs in many protected areas, which justifies a status of Least Concern LC. Protected in Colombia in Reserva Natural La Planada (Nariño), and in Farallones National Park (Valle). In Ecuador in the Mache-Chindul Ecological Reserve (Bilsa Biological Station, Esmeraldas), the Golondrinas Reserve (Carchi), and the Awá-Camumbi Ethnic Reserve (Esmeraldas and Carchi). In Costa Rica it is protected in the Rara Avis Private Reserve, in Volcán Tenorio National Park and in Monteverde Biological Reserve (Alajuela).
description: Published as part of Gamba, Diana & Almeda, Frank, 2014, Systematics of the Octopleura Clade of Miconia (Melastomataceae: Miconieae) in Tropical America, pp. 1-174 in Phytotaxa 179 (1) on pages 76-80, DOI: 10.11646/phytotaxa.179.1.1, http://zenodo.org/record/10089927