Chionanthus megistocarpus Fern.Alonso & Cogollo, 2016

Fernández-Alonso, José Luis & Cogollo-Pacheco, Álvaro Alfonso, 2016, Chionanthus megistocarpus (Oleaceae), a new species from the Western Cordillera of Colombia, Phytotaxa 269 (1), pp. 14-20 : 15-18

Chionanthus megistocarpus Fern.Alonso & Cogollo sp. nov. ( Figs. 1 , 2 , 3 )

Type:— COLOMBIA. Valle del Cauca, mun. de La Cumbre, Corregimiento de Bitaco, Reserva Agua Bonita , 1700–1900 m, vertiente occidental de la Cordillera Occidental ; 10–15 December 1998, (fl, fr), W. G. Vargas 5234 (holotype HUA-129462!) .

Chionanthus megistocarpus is similar to Chionanthus colonchensis Cornejo & Bonifaz , from the Pacific moist forest of Ecuador, but differs from the latter by its leaves with longer petioles [12–)15–30(–35) mm long], blade without domatia, longer inflorescences (10–20 cm long), shorter corollas (3–6 mm long) and larger fruits (45–50 × 42–47 mm).

Trees (10–) 15–30 m tall and 20–50 cm DBH; evergreen, young shoots yellowish, with noticeable lenticels; apex of shoots and buds with brown indumentum; hairs moniliform and flexuous, more or less bristly, soon deciduous; terminal buds with subcoriaceous cataphylls, 4–5 mm long, densely covered with brown to slightly silver hairs, appressed. Leaves opposite (rarely subopposite), without stipules; petioles flattened, more or less grooved on adaxial face, (12–)15–30(–35) mm long; with conspicuous basal pulvinus, up to 10 mm long, often bent at an angle of 45 degrees, glabrescent; blades coriaceous (papiraceous during anthesis) more or less delicate, obovate-lanceolate to elliptic, (10–)14–18 (up to 27 cm long in saplings) × (4–) 6–9 cm; base narrowly cuneate, gradually tapered to the petiole, apex usually obtuse, margin entire, thick and irregularly ondulate; midrib adaxially darker than the blade, with 10–13(– 14) pairs of secondary veins, impressed; abaxial side with prominent midrib and secondary veins, broquidodromous distally; third- and fourth-order veins polygonal-reticulated, slightly prominent; glabrescent beneath, without domatia at the confluence of lateral veins and midrib. Inflorescences axillary, large branched panicles, 8–16(–20) cm long, with 4–6 pairs of first order branches, 3–4 cm long, with bracts up to 15 mm long, yellowish-green, promptly deciduous; branches arranged in a cymose pattern and with pairs of persistent bracts 3–4 × 1–2 mm, narrowly lanceolate; all branches, bracts and pedicels densely covered by a thin, erect or ascending indumentum, brown or pale brown; third order branches 1–2 cm long, with cymes of dichasial type; each cyme accompanied by bracts, dry brown or light brown, broadly lanceolate, arched, obtuse, 2 × 0.9 mm, hairy. Flowers bisexual, fragrant, with pedicels 1–3 mm long, densely brown-pubescent; flower buds subglobose, with calyx lobes incurved, young petals arched and facing the axis of the flower; mature calyx persistent, short, cup-shaped, ca. 2 × 2.5 mm, with four lobes 0.4–0.6 mm long, broadly triangular or more often obtuse or rounded, slightly unequal, densely covered with short, brown indumentum; corolla white-green, membranous, rigid; four petals, linear or gradually widened at the base, apex slightly truncated, 3–6 mm × 0.3–0.4, glabrous on both sides or sparsely covered with a band of hairs on the outer side; stamens 2, 1–1.3 mm long, generally not exceding the calyx, the corolla and the pistil in length; filaments 0.2–0.3 mm long, connective very thin, shorter than the anther, without visible appendix, anther truncate-ellipsoid, ca. 1 × 0.7 mm, pistil ovoid-fusiform, 1.3–1.5 × 0.6 mm, gradually narrowed towards the style, stigma slightly 2-lobed. Fruit peduncle up to 5.5 cm long, usually with a single or few drupes developed; fruit subglobose to ellipsoid and purple when mature, 45–50 × 42–47 mm; epicarp with irregular surface, with sparsely distributed small lenticels or tubers, with a single large pyrene and a seed.

Etymology:— The specific epithet refers to the large size of the mature fruit, the largest for this genus in the Neotropics.

Distribution, habitat and phenology:— Chionanthus megistocarpus is only known from Subandean cloud forests, located between 1700–2100 m elevation in the Valle del Cauca, Colombia. It grows in pristine forests in the basin of the Bitaco river, a tributary of Dagua river. This region belongs to the western slope of the Western Cordillera of Colombia.

Specimens with flowers have been collected in December, and with fruits from July to December. Dispersion of the fruits of this species seems to be carried out by some kind of Caracidae and toucans ( Ramphastidae ) that inhabit these forests type ( Ríos et al. 2004).

Conservation status:— So far, the known distribution of Chionanthus megistocarpus , is restricted to the Subandean forest altitudinal range, in the Bitaco river basin, Western Cordillera of Colombia. In this region there are crops of tea ( Camelia sinensis ) and the forest remnants are undergoing some degree of alteration because of deforestation. According to the IUCN categories (2012) it should be considered in the category: data deficient (DD). Although it may probably be classified later as endangered (EN), if its restricted distribution associated with preserved relict forest is confirmed.

Aditional specimen examined:— COLOMBIA. Valle del Cauca, mun. de La Cumbre, Corregimiento de Bitaco , Vereda Chicoral, 2020 m, 3º33’56’’N, 76º35’3’’W, 23 July 2003 (fr), H. Mendoza et al. 15250 (CUVC-50208!, FMB-65599!) ; ibídem, 2093 m, 22 July 2003 (fr), H. Mendoza et al. 15252 (COL-568134!, FMB-100001!) ; ibídem, 2030 m, 23 July 2003, H. Mendoza et al. 15261 (FMB-65601!) ; ibídem, 2020 m, 23 July 2003, H. Mendoza et al. 15286 (FMB-65602!) ; ibídem, 2020 m, 23 July 2003, H. Mendoza et al. 15325 (FMB-67599!) ; ibídem, Reserva Agua Bonita, 1700–1900 m, 10–15 December 1998, (fr), W. G. Vargas 5358 (HUA-125583!) .

Discussion:— Chionanthus megistocarpus can be easily separated from the rest of the Neotropical species of the genus by its fruit size (4.5–5 cm long) and its obovate-elliptic and obtuse leaves, without domatia on the abaxial side. It is morphologically similar to C. colonchensis Cornejo & Bonifaz in Bonifaz & Cornejo (2004: 160–161), which grows in tropical moist forests (600 m) in western Ecuador, but this species can be separated by the presence of shorter petioles (5–18 mm) and longer blades (13.5–30 cm), with domatia, larger flower corolla (> 10 mm long) and black and smaller fruits (30–40 mm long) when mature. The other two Colombian species that grow in the range of Subandean forests, C. abriaquiensis (Fernández-Alonso & Cogollo 2016a) and C. vargasii (Fernández-Alonso & Cogollo, 2016b, in press) also have large inflorescences (> 10 cm long), but they can be clearly separated because, unlike C. megistocarpus , they have narrowly elliptic or oblong leaves, with 12–16 veins on each side, and domatia associated with the veins on the abaxial side of the leaves.

Figures

FIGURE 1. Chionanthus megistocarpus Fern.Alonso & Cogollo. A. Terminal branch showing the arrangement of the leaves. B. Fruit with partial fragment of a inflorescence branch and a sagittal section of a fruit showing the endocarp. C. Distal portion of an inflorescence branch (third-order branch), with cymes of dichasial type, with bracts. D. Flower showing the arrangement of sepals and petals. E. Dissected flower showing the calyx lobes, two sub-sessile stamens in their natural position, two petals and pistil. F. Detail of a stamen, the filament and the anthers. G. Pistil and the two divergent stigma lobes. A–B. Drawn from the paratype W. G. Vargas 5358 (HUA), C–G. from the holotype W. G. Vargas 5234 (HUA). Illustrations by Sergio Moreno.

FIGURE 2. Chionanthus megistocarpus Fern.Alonso & Cogollo. Photograph of two branches with inflorescences and open fruit remnants. Holotype, W.G. Vargas 5234 (HUA-129462).

FIGURE 3. Chionanthus megistocarpus Fern.Alonso & Cogollo. A. Terminal bud. B. Distal part of an inflorescence, with dichasia. C. Axes of the inflorescence with some immature fruits. D. Epicarp of the mature fruit showing inside the woody endocarp and seed. Photographs:A and D (Vargas 5358); B (Vargas 5234) and C (Mendoza 15252). Scale bars = 1.0 cm.