Begonia diegoi Jara, 2021

Jara-Muñoz, Orlando Adolfo, Richardson, James E. & Zabala-Rivera, Juan Carlos, 2021, Five new species and three new varieties of Begonia section Casparya endemic to Colombia, Phytotaxa 525 (4), pp. 258-280 : 261-263

Begonia diegoi Jara , sp. nov. Figs. 1 & 5

Type:— COLOMBIA. Magdalena: municipio de Ciénaga, corregimiento San Pedro de la Sierra, sector El Bosque , 10.905º N, 73.997º W, 2100 m, 12 November 2015, A. Jara & D. Yepes 2849 (holotype COL!, isotypes ANDES!, COL!, HT!, JBB!, UTMC!) .

Diagnosis:—Similar to Begonia pax , but differing in its larger outer tepals (10–16.5 × 3–7.3 mm vs. 4.8–9.9 × 1.4–2.8 mm), and its anthers, which are connivent forming a cylindrical structure. In B. pax the anthers are also convenient but form a fusiform structure, and also differ by the curved extension of the anther connective (vs. straight in Begonia pax ).

Description:—Caulescent herb, to 1 m high. Stem erect; internodes to 3.6 cm long, and to 3 mm thick, glabrous. Stipules sub-persistent, membranous, glabrous, pale green, ovate, 5.7–6.8 × 1.9–3.3 mm, apex obtuse, setulose, margin entire. Petiole glabrous or pilose toward the apex, green, 2.3–3.5 (10.7) mm long, lamina of the leaf straight to the petiole, membranous, asymmetric, ovate or elliptic, 3.5–9.4 × 1.4–3.2 cm, base unequal, lobulated or rounded on one side, obtuse or rounded on the other side, margin doubly-serrate, ciliate, apex acute or short acuminate, lower surface pale green, pilose on the veins, upper surface dark green, disperse pilose, pubescent on the veins, venation pinnate, 5–8 veined pairs from the base. Inflorescence unisexual in monoecious plants, however, based on field observation some individuals are unisexual. staminate inflorescence axillary, erect, like-umbel cincinnus, not branched, bearing up to 3 staminate flowers; peduncle glabrous, green, to 2.2 cm long, bracts deciduous, glabrous, pale green or hyaline, ovate, ca. 7.9 × 4.5 mm, margin entire, apex obtuse. staminate flowers: pedicels glabrous, to 16 mm long; tepals 4, spreading, outer 2 glabrous, white, elliptic, 10–16.5 × 3–7.3 mm, margin entire, apex obtuse, inner 2 glabrous, white, oblong, 9.2–11.2 × 1.6–3 mm, margin entire, apex obtuse; stamens 6–9, connivent forming a cylindrical structure, filaments whitish, 0.4–0.6 mm long, connate on a short torus of ca. 1 mm long, anthers yellow, linear-oblong, 3.3–3.5 × ca. 0.5 mm, dehiscence slightly introrse, connectives produced ca. 1 mm, with the produced part curved outward. Pistillate inflorescence, solitary flowers. Pistillate flowers: pedicels to 19 mm long; bracteoles not seen; ovary, glabrous, obdeltoid, 10–12 × 15–20 mm, equally 3-horned, horns slightly curved upward, placenta simple, bearing ovules on both surfaces; tepals 5, spreading, slightly differing in form and size, the largest glabrous, white, elliptic, 17–19 × 7–9 mm, margin entire, apex rounded, the smallest glabrous, white, 12–15 × 5–7 mm, margin entire, apex obtuse; styles 3, fused at the base, yellow, 7–9 mm long, apex slightly flattened, stigmatic surface papillate and restricted to the apex. Fruiting pedicel to 17 mm long; capsule body and horns shape as in ovary, to 11 × 26 mm, apical column short, ca. 5 mm.

Etymology:—The name of this species is in memoriam of the Colombian botanist Diego Yepes, who sadly died at a young age in 2018. He was a passionate orchidologist, mainly studying orchids from the Sierra Nevada de Santa Marta, and he accompanied the first author on an expedition to find new specimens of this species in 2015.

Distribution and habitat:—Endemic to the Northern and Western part of the Sierra Nevada de Santa Marta, between 1400 and 2000 m. This elevation range is included in a zone of cloud forest vegetation, and characterized as sub-Andean forest ( Cuatrecasas 1958, Hernandez-C. & Sanchez 1992). The well conserved patches of forest in this zone have a canopy between 25 and 35 m tall, the undergrowth has abundant arborescent ferns and palms, as well as many epiphytes and woody lianas. The species was seen growing on rocks of a small stream, covered by dense arborescent vegetation, and surrounded by shrubs, herbs and mosses.

Conservation status:― We assess this species as endangered (EN B2a,b(ii)) because its EOO is less than 5000 km 2 (21.2 km 2), and AOO is less than 500 km 2 (12 km 2), and it is known from fewer than five locations (criterion B2a) and an observed reduction in the area of occupancy (criterion B2b(ii)). Close to the area where the species grows is the Sierra Nevada de Santa Marta National Park, a conservation area, however the lower park border is at 2000 m elevation, while the species grows just below this level, so the known populations are not protected. The area covered by montane forest in the region has declined drastically during the last five decades, in some cases the reduction of the original vegetation is 80% ( Fundación ProSierra 1991).

Notes:—This species is part of the group II, sensu Jara et al. (2019) of Casparya , which is characterized by unisexual inflorescences, with solitary pistillate flowers, and acolumnar fruits. ITS sequences of this species were included in Jara et al (2019), (sp. nov. 7), showing evidence for its close relationship with species in the eastern Cordillera with similar morphological characteristics to B. pax and B. solaniflora . This species can be distinguished from the rest of the group by its curved anther connectives, the stamens connivent forming a cylindrical structure, and its larger staminate flowers.

Additional specimens examined:— COLOMBIA. Magdalena: Cienaga, corregimiento San Pedro de la Sierra , sector El Bosque, 12 November 2015, 1600–1700 m, A. Jara & D. Yepes 2849 ( ANDES, COL) ; Sierra Nevada de Santa Marta, along quebrada on S portion of finca Reflejo , 10º59′N, 73º59′W, ca. 1450 m, 07 September 1972, J.H. Kirkbride, Jr., 2160 ( COL, US) ; In forest N of finca Los Arroyitos , 10º56′N, 73º58′W, ca. 1800 m, 28 September 1972, J.H. Kirkbride, Jr., 2238 ( COL, US) ; alto río Buritaca , alto de Mira , por el camino a la cascada del caño Negro hasta la finca de Merardo , 11º05′N, 73º48′W, 900–1100 m, 15 July 1989, S. Madriñán & C. Barbosa 262 ( ANDES, MO) ; alto río Buritaca , Ciudad Perdida , 11º04′N, 73º48′W, 1100 m, 18 July 1989, S. Madriñán & C. Barbosa 373 ( MO) .

Figures

FIGURE 1. Begonia diegoi Jara. A) Branch, B) Young inflorescence, C) Inflorescence with staminate flowers open, D) Inmature fruit. Based on A. Jara & D. Yepes 2849, by O. Bernal.

FIGURE 5. Distribution of Begonia diegoi, Begonia galenoi, Begonia kalbreyeri var. oquidensis, and Begonia mamapachensis.