51. Begonia huancabambae Moonlight sp. nov.

urn:lsid:ipni.org:names:77323295-1

Figs 65D, 68

Begonia velata auct. non L.B.Sm. & B.G.Schub.: Tebbitt, Edinburgh Journal of Botany 74 (2): 226 (Tebbitt 2017).

Begonia velata auct. non L.B.Sm & B.G.Schub.: Moonlight et al., Taxon 67 (2): 295 (Moonlight et al. 2018).

Diagnosis

Most similar to B. acerifolia but differs in having a ring of trichomes at the leaf apex (vs glabrous or with scattered hairs at the leaf apex); and in having sub-symmetrical leaves that are orbicular in outline (vs asymmetrical with an ovate outline).

Etymology

Named for the Huancabamba depression, which is where the species is found. The area is likely a centre of origin of Andean begonias.

Type

PERU – Cajamarca Region: Prov. Cotumazá • Bosque Cachil ; [6°23′ S, 79°17′ W]; 2500 m a.s.l.; 16 Jun. 1994; A. Ságastegui A. & S. Leiva G. 15307; holotype: US [US0051126]; isotype: MO [MO-1643554].

Selected specimens examined

PERU – Piura Region: Prov. Morropón • Dist. Chalaco, cima del cerro Mijal ; [5°05′ S, 79°45′ W]; 3100 m a.s.l.; 10 May 2003; I. Sánchez V., R. Cruz C. & E. Peña C. 11952; CPUN. – Prov. Huancabamba • Canchaque-Minas Turmalina ; [5°03′ S, 79°49′ W]; 2200 m a.s.l.; 23 Jul. 1975; A. Ságastegui A., J. Cabanillas S. & O. Dios C. 8279; HUT, MO [MO-2180420], US [US00222067] • Dist. Canchaque, Chorro Blanco ; [5°20′ S, 79°36′ W]; 1500–1900 m a.s.l.; 17 Apr. 1987; C. Díaz & S. Baldeón M. 2457; MO [MO-1643556], USM • Above Palambla ; 5°22′ S, 79°35′ W; 1711–2300 m a.s.l.; 27 May 2014; M.C. Tebbitt & A. Daza 838; MOL • Above Canchanque on the Huancabamba pass ; 5°22′35″ S, 79°34′59″ W; 1758 m a.s.l.; 27 Jan. 2016; P.W. Moonlight & A. Daza 107; E [E00885597], MO [MO-3254800], MOL • ca 70 km east of Olmos; [5°51′ S, 79°31′ W]; 2035 m a.s.l.; H. Ellenberg 3705; US [US00222069]; – Cajamarca Region: Prov. Cotumazá • ca 3 km (por aire) ENE Monteseco; [6°51′ S, 79°06′ W]; 1800 m a.s.l.; 9 May 1987; J. Santisteban C. & J. Guevara B. 34; F, HUT, MO [MO-1643550], NY, US [US00222346].

Description

Caulescent, rhizomatous herb, to 200 cm high. Rhizome ellipsoid, 5–20 × 0.75–2.5 cm, unbranched, with> 1 growing point per branch. Stem erect, unbranched; internodes to 19 cm long, to 8 mm thick, succulent, pale red, glabrous. Stipules persistent on the rhizome, tardily deciduous on the stem, ovate, 5–18 × 5–9 mm, apex acuminate, opaque, pale green, glabrous, margin entire, aciliate. Leaves 1–5 per stem, alternate, basifixed; petiole 3–25 cm long, pale green to red, glabrous but with a ring of squamous hairs at the apex of the petiole; blade subsymmetric, orbicular in outline, to 25 × 32 cm, succulent, apex acuminate, base cordate, basal lobes not overlapping, sinus to 8.5 mm deep, margin with 4 or 6 triangular lobes around the lamina, serrulate to serrate, ciliate, upper surface green, pilose, lower surface pale, flushed red between the major veins, glabrous, sparsely to densely pilose on the veins, veins palmate but with one primary vein, 6–8 veined from the base, with 1–3 secondary veins on the larger side, 1–3 secondary veins on the smaller side. Inflorescences 1–3 per stem, bisexual, axillary, erect, cymose, with up to 3 branches, bearing up to 8 staminate flowers and 8 pistillate flowers, protandrous; peduncle to 40 cm long, green flushed red, glabrous, bracts deciduous, ovate, 7–14 × 4–7 mm, opaque, colour unknown, glabrous, apex obtuse, margin entire, aciliate. Staminate flowers: pedicels to 65 mm long, glabrous; tepals 4, spreading, outer 2 obovate to broadly obovate, 15–25 × 12–20 mm, apex rounded, white, sometimes flushed green or pink on the outside, glabrous, margin entire, aciliate, inner 2 obovate, 11–24 × 5–17 mm, apex rounded, white, sometimes flushed green or pink on the outside, glabrous, margin entire, aciliate; stamens 50–75, spreading, yellow, filaments 2.5–5 mm long, fused at the base, anthers broadly obovoid, 1–1.5 × 0.75–1 mm, dehiscing via lateral slits, connectives not extending, symmetrically basifixed. Pistillate flowers: pedicels to 31 mm long; bracteoles absent; tepals 5, subequal, deciduous in fruit, spreading, obovate, 5–12 × 4–12 mm, apex rounded, white, sometimes flushed pink or green outside, glabrous, margin entire, aciliate; ovary body ovoid, 4.5–10 × 3–6 mm, pale green flushed pink, glabrous, unequally 3-winged, the largest triangular 7–16 × 5–11 mm, the smallest rib-like, to 1 mm wide; 3-locular, placentae branches divided, bearing ovules on both surfaces; styles 3, yellow, fused at the base, 3–6 mm long, once-divided, stigmatic papillae in a spirally twisted band. Fruiting pedicel to 35 mm long. Fruit body ovate, to 15 × 10 mm, drying brown, the wings same shape as in ovary, the largest expanding to 16 × 21 mm, the smallest expanding to 2 mm wide.

Proposed conservation assessment

Known from three fragments of highly threatened northwest Peruvian relict montane forest on the western slopes of the Andes. The most distant sites are approximately 220 km apart and none are protected. Given the species low EOO (ca 1200 km 2), its few known localities and fragmented distribution, and the threats to its habitat, we assess B. huancabambae sp. nov. as Endangered (EN B1ab(iii)).

Notes

The holotype of B. huancabambae sp. nov. has two staminate flowers with the normal four tepals and ca 75 stamens and a third, aberrant flower with ca 6 flowers and> 100 stamens. The aberrant flower is excluded from our description.

Tebbitt (2017) published an emended description of B. velata based upon living plants collected at the type locality (M.C. Tebbitt & A. Daza 838). These specimens represent a species superficially similar to the type collection of B. velata but differing in several key characters. For example, Tebbitt’s collection is rhizomatous (vs tuberous, though this was not known at the time); it has a ring of hairs at the apex of the petiole and scattered, simple hairs across the upper and lower surface of the leaf (vs glabrous petiole and leaves); it has large, persistent stipules (vs inconspicuous and deciduous); it has small (up to 16 × 10 mm), green bracts that do not cover the inflorescence (vs large, up to 28 × 22 mm, white flushed pink bracts, frequently covering the developing inflorescence). Tebbitt’s collection instead represented an undescribed species, which we describe herein as B. huancabambae sp. nov.

Moonlight et al. (2018) also published a sequence made from a plant collected the type locality of B. velata and matching Tebbitt’s description of B. velata . The sequence data they provided in Moonlight et al. (2018) is instead the newly described B. huancabambae . Tebbitt (2017) discussed that his concept of B. velata had a possible hybrid origin from B. ludwigii and B. acerifolia because of unpublished sequence data (later published in Moonlight et al. 2018) and because both species have a ring of hairs around the petiole apex. This speculation is reasonable but should now be applied to B. huancabambae sp. nov.

Identification notes

Superficially similar to B. acerifolia but differing in the outline of its leaves, which are more or less symmetrical with an orbicular outline (vs asymmetrical with an ovate outline). It also has a ring of small trichomes around the apex of its petiole, which is absent in B. acerifolia . It is also similar to B. velata but has an above-ground rhizome rather than a subterraneous tuber.

Distribution and ecology

Endemic to Peru and known from Piura and Cajamarca Regions (Fig. 65D). Found in northwest Peruvian montane forests at an elevation of 1800–3100 m a.s.l.