Begonia embera Jara & D.Franco, 2022

Jara-Muñoz, Orland Adolfo, Franco, Daniel, Mark, Tebbitt & Swensen, Susan, 2022, A NEW SPECIES OF BEGONIA FROM THE CHOCÓ BIOGEOGRAPHICAL REGION OF COLOMBIA, Edinburgh Journal of Botany 79 (399), pp. 1-12 : 3-9

Begonia embera Jara & D.Franco , sp. nov.

In Begonia sect. Ruizopavonia , B. embera is most similar to B. harlingii L.B.Sm. & Wassh. but is distinguished by its much shorter petioles (1.5–5.6 mm vs 25–75 mm), narrower leaves (1.5–2.8 cm vs 3–6 cm) and fewer secondary veins (4–6 vs 9–13). Floral differences include the smaller outer staminate tepals (2.7–4.5 × 1.4–2.5 mm vs 5–10 × c. 5 mm), female flowers with 3 bracteoles (vs 2 in B. harlingii ) and shorter styles (0.7–2.1 mm vs 4–5.5 mm).

– Type: Colombia, Chocó, municipio El Carmen del Atrato, vereda El Doce , carretera Medellín-Quibdó , km 150, 700 m, 6 vi 1979, G. Galeano & R. Bernal 98 (holotype COL [barcode: COL000138608 ], isotype HUA). Figures 2 , 3 .

Cane-like herb, to 30 cm tall, without tubers or rhizomes. Stem 0.7–2.7 mm in diameter, unbranching or branching near to the base, reddish green, nodes thickened, internodes 4.2–26 mm long. Stipules persistent, membranous, glabrous, hyaline to light green, oblong, 4.5–12.2 mm long, margin entire, apex acuminate. Leaves distichous, c.6 per stem; petiole glabrous, 1.5–5.6 mm long; leaf blade straight to the petiole, dark green above, pale green below, hairs only on the midvein above and on the margin, slightly asymmetrical, narrowly oblong-obovate, 4.3–10 × 1.5–2.8 cm, apex acuminate, base acute, truncate, or shallowly cordate, with one side connecting to the petiole c. 2 mm above the other, margin biserrate with a seta at the end of each tooth, venation pinnate, 4–6 secondary veins per side. Inflorescence: 1–3 per plant, axillary, cymose, with 3 male flowers and 1 female flower per inflorescence, protandrous; peduncle erect, reddish white, glabrous, 1.3–4 cm long; bracts persistent, hyaline, elliptic, 4–7.5 × 1.7–2.8 mm, apex acute, margin fimbriate. Staminate flowers: pedicels white, glabrous, 4.5–7 mm long; tepals spread apart, 4 in two series, white, glabrous, outer two broadly ovate, 2.7–4.5 × 1.4–2.5 mm, apex rounded, base obtuse, margin entire, inner two elliptic, 2.5–3.2 × 1–1.8 mm, base obtuse, apex rounded, margin entire; stamens 10–15, on a short torus, filaments white, glabrous, 0.2–1 mm long, anthers linear-oblong, longer than the filaments, 1.2–2 mm long, dehiscence longitudinal by lateral slits, connective projecting 0.2–0.4 mm long, with a rounded tip. Pistillate flowers: pedicels white, glabrous, 0.7–2 mm long; bracteoles 3, on the base of the ovary, subpersistent, hyaline, elliptic, 4.3–8 × 2.7–4.7 mm, margin ciliate, apex acute; ovary glabrous, body fusiform, 2.8–3.9 × 2.4–3.9 mm, wings asymmetrically triangular, with the short side distal, perpendicular to the axis, and the long side proximal and roughly at 45° to the axis, subequal or the adaxial wing slightly longer, apex obtuse, 3-locular; placentation axillary, placentas bilamellate, with ovules on both sides; tepals 5, deciduous in fruit, spread apart, white, oblanceolate, 6.5–9.3 × 2.5–3.3 mm; styles 3, free, 0.7–2.1 mm long, bifid, stigmatic papillae twisted. Fruiting peduncle erect above the branches, mature fruit at c.90° to the peduncle, the body shape and wings similar to the ovary, wings 6.1–8.4 mm long.

Habitat and distribution. Begonia embera is endemic to the Chocó Department, in the western foothills of the Colombian Cordillera Occidental, in the transition between the Chocó and Andean biogeographical regions ( Figure 4 ). The plants were observed growing in humid and shady places, always near or in streams, on substrate formed mainly by gabbro rocks, or on sandy soil. The plants are not grouped into dense populations, and are accompanied in the same strata of the forest mainly by species of Gesneriaceae , Piperaceae and Urticaceae .

Etymology. The new species is named in honour of the Emberá, the groups of indigenous peoples who reside in the Pacific Coast of Colombia, Panama and Ecuador. The Emberá Katío and Chamí peoples share their territory with the new Begonia species, and both are critically threatened by external factors.

Proposed IUCN conservation category. After recognition of this taxonomic novelty, two expeditions to the area were carried out to find more populations. Despite the additional fieldwork, we found live plants in only one small area. The area of occupancy is less than 10 km 2, and the extent of occurrence is less than 100 km 2. During the second expedition, we observed an increase in settlements in the vicinity of the type locality, as well as maintenance and expansion work on the Medellín–Quibdó road, along the sides of which individuals were found. We observe from live material cultivated in a greenhouse that the new species requires high relative humidity and low light levels. These observations provide insights into the habitat requirements of the species, which is probably restricted to narrow basins under dense canopy. In light of the considerations above, according to IUCN criteria ( IUCN Standards and Petitions Committee, 2022), Begonia embera is categorised as Critically Endangered [CR B1ab(iii) + 2ab(iii)].

Additional specimens examined. COLOMBIA. Chocó: municipio El Carmen del Atrato , carretera entre Ciudad Bolivar y Quibdó, 500 m, 2 v 2015, A. Jara & D. White 2796 ( ANDES) ; municipio El Carmen del Atrato , carretera entre Ciudad Bolivar y Quibdó, 545 m altitude, 5.74513°N, 76.29838°W, 2 v 2015, A. Jara & D. White 2799 ( ANDES) .

Figures

Figure 2. Begonia embera Jara & D.Franco, sp. nov. A, Sterile branch; B, detail of the inflorescence; C, staminate flower; D, detail of one stamen; E, pistillate flower; F, transverse section of the ovary; G, young fruit with bracteole; H, fruit without bracteoles. Drawn from G. Galeano & R. Bernal 98 (the type specimen), A. Jara & D. White 2796 and A. Jara & D. White 2799, by Omar Bernal.

Figure 3. Begonia embera Jara & D.Franco, sp. nov. A, Staminate flower; B, pistillate flower; C, plant habit; D, habitat of the species. Photographs of A. Jara & D. White 2796, taken by Angela Sanchez.

Figure 4. Distribution map for Begonia embera (red diamonds).