Miconia yeseniae W. Palacios, D. Fernández & Michelang., 2018

Palacios, Walter A., Fernández-Fernández, Diana M. & Michelangeli, Fabián A., 2018, A new species of Miconia (Miconieae, Melastomataceae) from Northwest Ecuador, Phytotaxa 379 (3), pp. 247-254 : 248-253

Miconia yeseniae W. Palacios, D. Fernández & Michelang. , sp. nov. ( Fig. 1–3 )

Type:— ECUADOR. Carchi: Cantón Tulcán, Chical, Carretera Gualchán-El Carmen. Faldas de Cerro Golondrinas, cerca del puente del río Gualpí, km 13. Bosque extremadamente húmedo, árboles cargados de epífitas, 0°50’13 N, 78°13’23 O, 1950 m, Jul 2017, W. Palacios y L. Mejía 18251 (fl) (holotype: QCNE 243161!).

Diagnosis:—Young leaves lower surface purple turning green in adult state; panicle 16–27 cm long; floral buds curved downwards; hypanthium 3.5–4.5 mm long, cupuliform, glabrous; calyx with 5 subulate external teeth, 4.9–5.1 mm long; petals 5, 1.2–1.8 × 1.0– 1.4 cm, pink to pinkish-white, densely papillose outside; filaments flat, 4.8–5.2 mm long, with glandular trichomes, especially at the apex; anthers with incompletely divided 2-locular thecae, 2.9–3.1 mm long, opening by one apical-dorsal pore. Ovary 5-locular, with 10 angles, ending in 10 acute lobes; stigma peltate with glandular trichomes.

Tree, up to 8 m tall. Young stems terete, glabrous. Young bud leaves glabrous, dark purple; internodes 2–3.5 cm long; obvious interpeciolar line arc-shape. Leaves opposite and decussate; petioles 1.5–3.5 cm long, glabrous; blade 9–15 × 4–8 cm, narrowly elliptical or less frequently elliptic, coriaceous, glabrous on both surfaces, apex acute, base obtuse, margin entire, slightly revolute but more accentuated towards the base of lamina; young leaves purple on the abaxial surface, later becoming green; venation acrodromous, suprabasal, with two pairs of secondary veins, including the faint marginal pair, the internal pair diverging 5–7 mm above the base and running 0.8–1.7 cm from margin, the external pair 1–2.3 mm from margin; tertiary venation curved-scalariform, 33–37 veins per side and spaced ca. 3–9 mm; quaternary venation forming quadrangular areolae 1–3 mm wide, evident on the abaxial surface. Inflorescences a terminal pyramidal thyrse, 16–27 cm long, 4–5 branched, basal branches 8–13 cm long, secondary branches ending in groups of three flower; peduncles terete, glabrous, pinkish-brown; pedicels 2–3 mm long, glabrous, terete, thick, pinkish-brown, curved downwards at 50–80° angle in bud; bracteoles early caduceus, ca. 7 × 1 mm long; flowers 5- merous, bisexual; hypanthium 3.5–4.5 mm long, 3–4 mm wide at the torus, campanulate, glabrous, reddish-pink; calyx tube 0.5–0.9 mm, glabrous to very sparsely pubescent, reddish-pink outside, violet inside; calyx internal lobes widely ovate, 1–1.2 × 1.4–1.6 mm; calyx external teeth widely subulate, 2.9–3.4 mm long, glabrous, reddish-pink outside, violet inside; petals 1.2–1.8 × 1.0– 1.4 cm, imbricate, obovate, apex rounded, base attenuate, dark pink at pre-anthesis, dark pink outside and pinkish-white inside at anthesis, densely granulose outside, persistent after the stamens have fallen off; stamens 10, slightly geniculate between anthers and filaments, isomorphic, filaments flat, 4.8–5.2 mm long, pinkish-white to pale yellow, with glandular trichomes, these more dense in the distal portion; anthers bright yellow, with incompletely divided 2-locular thecae, 2.9–3.1 mm long, 1–1.5 mm width, flattened on the ventral side, opening by one apical-dorsal pore, 0.2–0.4 mm width, glabrous, except for some sparse glandular trichomes at the base; ovary ovoid, 4–4.5 × 3.5–4.5 mm, strongly 10-sulcate at the apex with 10 acute lobes, 1 / 3 inferior, 5-locular, the free portion 2.5–3.0 mm long, glabrous; style 4–5 mm long, erect, pinkish-white to pale yellow, with glandular trichomes; stigma peltate, 3–4 mm wide, pale yellow. Fruit not seen.

Distribution and ecology:— Miconia yeseniae is only known from the type locality in Carchi province, between 1900–2000 m. The area where the species grows is extremely humid, the trees are loaded with epiphytic mosses, orchids, ferns and aroids. Miconia yeseniae has been found in secondary forests or gaps of the primary forest. Species collections were made in disturbed areas at the roadside margins, out of the nearest natural reserve, Bosque Protector Cerro Golondrinas ( Fig. 4).

Phenology:—In July 2015, when the first collection was made, there were numerous trees with flowers, but during the second collection, in July 2017, only one tree with flowers was found.

Etymology:—The name of the species is in honor to Yesenia, daughter of the first author.

Conservation status:— Miconia yeseniae is considered endemic to Ecuador, although it may occur in similar environments in neighboring Colombia. According to the known area of occupation, we recommend that M. yeseniae is categorized as Critically Endangered CR B2ab (ii, iv) ( IUCN 2017). The forests where the species grows are rapidly being destroyed to establish pastures; however, low soil fertility and extreme humidity do not favor its development. To break the aggressive regeneration of native vegetation, the farmers are using large amounts of herbicides to promote pasture growth. This situation threatens the presence of this species, as well as many other that are known only from the Cerro Golondrinas (see Palacios 2012, Palacios & Jaramillo 2016).

Taxonomic relationships:—Based on morphological character of the flowers, the obovate anthers opening by small pores in particular, Miconia yeseniae could be assigned in Miconia sect. Amblyarrhena ( Naudin 1850: 204) Triana ex Hook.f. (in Bentham & Hooker 1867: 763) following Triana’s (1871) or Cogniaux’s criteria (1891). However, it should be noted that Miconia section Amblyarrhena is not monophyletic, with most of the species found in a clade in the northern Andes or at the base of a larger Andean clade ( Goldenberg et al. 2008). Based on anther morphology and color, as well as style and stigma morphology and pubescence, this new species is most similar to a group of Andean Miconia putative related to Miconia glandulistyla Wurdack (1978: 287) and Miconia floribunda Bonpland in Humboldt & Bonpland (1816: 123, Candolle 1828: 188), characterized by large flowers with thick and puberulent petals, yellow anthers with glandular trichomes, pubescent filaments and/or styles and capitate to expanded or funnelform stigmas.

The most distinctive characteristics of the new species are the long subulate external teeth of the calyx that project well beyond the interior lobes, and the 10-sulcate ovary. In addition, the large pink flowers of the new species are only found in a few species of Andean Miconia : Miconia codonostigma Gleason & Wurdack 1978: 289 and M. glandulistyla Wurdack 1978: 287 ( Table 1).

Most species of Miconia usually have lobed calyx with inconspicuous external teeth ( Wurdack 1980). In a few cases (e.g., M. idiogena Wurdack 1975: 496 ) the external calyx teeth exceed the inner lobes in size; therefore, this characteristic is very distinctive in the new species. Other similar species is M. grandiflora Cogniaux (1886: 25) known from the Andean zones of Antioquia, Colombia. It has a vegetative morphology very similar to M. yeseniae , but with leaves pubescent on the abaxial surface and the calyx with ovate lobes.

Additional specimens examined:— ECUADOR. Carchi: Cantón Tulcán, Chical, área alrededor del Río Gualpi, cruce del puente, Vía El Carmen-Chical, km 14, sitio extremadamente húmedo, 1900 m, 22 Julio 2015, W. Palacios & J. Robayo 17723 (fl) (QCNE!).

Figures

FIGURE 1. Miconia yeseniae: Branch and inflorescence (W. Palacios & J. Robayo 17723). Photograph by W. Palacios.

FIGURE 2. Miconia yeseniae: A. Leaf lower surface (scale bar = 1 cm). B. Flower buds (scale bar = 1 cm). C. Opened flower (scale bar = 1 cm). D. Calyx (petals removed; scale bar = 3 mm) inside and upper part of the hypanthium and ovary. E. Stamens and pistil (scale bar = 3 mm). (W. Palacios & L. Mejía 18251). Photographs by W. Palacios.

FIGURE 3. Miconia yeseniae. A. Detail of ovary (longitudinal section), sepals, style and stigma. B. Flower bud. C. Petal. D. Detail of ovary. E. Cross section of ovary. F. Side view of stamen (from W. Palacios & L. Mejía 18251). Illustrated by D. Fernández.