Begonia silverstonei var. brevipetiolata 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 : 273-274

Begonia silverstonei var. brevipetiolata Jara , var. nov. Figs. 7 & 10

Type:— COLOMBIA. Valle del Cauca. Municipio Dagua , vía entre El Queremal y La Elsa, 3°31′59″N, 76°45′3″, 1335 m, 28 October 2019, A. Jara, S. Urbano , A . Del Risco 3624 (holotype JBB!, isotype COL!) .

Diagnosis:—Differs from the type variety by the shorter petioles 1.8–3.9 (-13.3) vs. 5.4–30.6 mm, and because this variety has 4 tepals in the pistillate flower instead of 5 as in the type variety.

Description:—Caulescent herb, to 70 cm high. Stem erect, glabrous, internodes to 6.3 cm long, and to 3.8 mm thick, green and reddish-green in the younger parts. Stipules early deciduous, glabrous, oblong, 15.8–22 × 4.2–8.9 mm, margin entire, apex obtuse and 1-setulose. Petiole pubescent above, green, 1.8–3.9 (13.3) cm long; lamina of leaf straight to the petiole, thin coriaceous, slightly asymmetric, ovate, 8.4–13.6 × 4.2–6.3 cm, base rounded on one side, auriculate on the other side, margin doubly serrate, apex short acuminate, upper surface dark green, spread pilose, lower surface pale green, puberulous on the veins, veins palmate-pinnate, 8–10 on each side. Inflorescence bisexual, axillary, erect, a not branched umbel-like contracted cincinnus, bearing up to 3 staminate and 1 pistillate flowers, protandrous; peduncle to 3.9 cm long, glabrous, reddish-green, bracts deciduous, glabrous, elliptic, 12.3–12.7 × 4.2– 4.5 mm, margin entire, apex obtuse. staminate flowers: pedicels glabrous, to 12.6 mm long; perianth in two series, the outer one glabrous, red vermilion, deeply bilabiate and dorsiventrally flattened, broadly oblong to sub-orbicular, 12.2–16.8 × 11–15.6 mm, base cordate, apex rounded or truncated, inner series with 2 free tepals much smaller than the outer series, tepals glabrous, pale red, 3.6–2.9 × 4.2–4.7 mm, base rounded, margin entire, apex crenate; stamens 6, free, projecting, yellow, filaments ca. 2 mm long, anthers oblong, 2.4–2.7 × 0.6–0.8 mm, dehiscence slightly introrse, connectives shorty projecting, truncate. Pistillate flowers: pedicels glabrous, reddish-green, to 13 mm long; bracteoles 1, deciduous, glabrous, hyaline, concave, covering one of the horns of the ovary, ovate-elliptic, ca, 10 × 6 mm, margin entire, apex obtuse; ovary turbinate, ca. 8.5 × 18 mm, green, glabrous, equally 3-horned, horns curved upward; placenta entire, bearing ovules on both surfaces; perianth glabrous, red vermilion, campanulate, 4 tepals in two series, the outer tepals obovate, ca. 15 × 9 mm, margin entire, apex rounded, the inner series with one of the tepals slightly smaller and similar in form to the outer ones, and the other one bigger and bilobulate, ca. 17 × 15 mm, apex retuse; styles multifid, yellow, fused toward the base, ca. 2 mm long, stigmatic papillae restricted to the apex. Fruiting peduncle and pedicel to 63 mm long; capsule body like the ovary, to 19 × 29 mm, horns the same shape as in ovary; apical column to 11 mm tall.

Etymology:—The name of this variety refers to the shorter petioles compared to the type variety.

Distribution and habitat:—This variety has been recorded only in the department of Valle del Cauca, in humid forests, between 1900 and 2000 m.

Notes:—As well as the shorter petioles, this variety has 4 instead of 5 tepals in the pistillate flowers. It is likely that this reduction is derived from the fusion of two inner tepals, as the bilobulate form of the largest tepal suggests. This variety is also sympatric with Begonia libera and shares numerous vegetative and reproductive features, however Begonia libera can be recognized by its hispidous stems, and papillate-pubescent leaves.

Additional specimens examined:— COLOMBIA. Valle del Cauca: 53 km on road to Buenaventura from Cali , 4000 ft alt. 9 August 1968, F. A . Barklay 38c637 ( US); along highway 19 from Cali to Buenaventura , ca. 4 km west of Salaito , vicinity of km. 18, 3°30’36”N, 76°37’00”W, 17 July 1997, T . Croat & J. F . Gaskin 79960 ( MO); Hoya del río Dagua, quebrada de San Juan, abajo de Queremal , 1350 m, 8 November 1946, J . Cuatrecasas 22746 ( US); municipio La Cumbre, corregimiento Bitaco , reserva Agua Bonita , 1700–1900 m, 10-15 December 1998, W . Vargas 5381 ( HUA) .

Figures

FIGURE 7. Begonia silverstonei var. brevipetiolata. A) Branch with flowers, B) Staminate flower without the inner series of tepals, C) Pistilalte flower showing the ovary, the bracteole, and the outer perianth, D) Fruit, E) Cross section of the fruit. Based on A. Jara et al. 3624, by O. Bernal.

FIGURE 10. Distribution of Begonia silverstonei var. brevipetiolata, Begonia perijaensis, Begonia vinagrera var. vinagrera, and Begonia vinagrera var. pomecensis.