Begonia piurensis L.B.Sm. & B.G.Schub.

Moonlight, Peter. W., Jara-Muñoz, Orlando A., Purvis, David A., Delves, Jay, Allen, Josh P. & Reynel, Carlos, 2023, The genus Begonia (Begoniaceae) in Peru, European Journal of Taxonomy 881, pp. 1-334 : 197-199

47. Begonia piurensis L.B.Sm. & B.G.Schub.

Publications of the Field Museum of Natural History, Botanical Series 13 (4/1): 197 ( Smith & Schubert 1941a).

– Type: PERU – Piura Region: Prov. Huancabamba • Quebradas immediately NW of Canchaque ; on clay banks beside trail, also commonly along road below Canchaque; [5°22′ S, 79°36′ W]; 1200 m a.s.l.; 4 Apr. 1939; H.E. Stork 11393; holotype: UC [ UC640259 ]; isotypes: G, GH [ GH00068265 ], K.

Smith & Schubert (1952: 39); Smith & Wasshausen (1979: 247, 1983: 298, 1986: 52); Brako & Zarucchi (1993: 194).

Etymology

The type specimen was collected in Peru’s Piura Region by H.E. Stork and the species is named for this locality.

Specimens examined

PERU – Piura Region: Prov. Morropón • El Palto-Santo Domingo , 5°02′55″ S, 79°51′07″ W; 1320 m a.s.l.; 22 Jun. 2004; A. Sagástegui A., C. Téllez, F. Torres, M. Berrú & W. García 17485; US [ US01913139 ]. – Prov. Huancabamba • Dist. Canchaque, Chorro Blanco ; 5°21′01″ S, 79°36′13″ W; 1500–1900 m a.s.l.; 18 Jun. 1987; C. Díaz & S. Baldeón M. 2465; F, MO [ MO-098011 ], USM • Dist. Canchaque; [5°22′ S, 79°36′ W]; 1200–1300 m a.s.l.; 22 May 1948; R. Ferreyra 3092; USM • Dist. Canchaque, Ravine 100 m from centre of Canchaque , over metal suspension footbridge, 5°22′30″ S, 79°36′23″ W; 1199 m a.s.l.; 27 Jan. 2016; P.W. Moonlight & A. Daza 111; E [ E00885468 ], MO, MOL.

Description

Caulescent, tuberous herb, to 1 m high. Tuber spheroid, ca 4 × 4 cm, with 1 growing point. Stem erect, unbranched; internodes to 20 cm long, to 7 mm thick, succulent, green, glabrous. Stipules deciduous, ovate, ca 12 × 6 mm, apex acute, translucent, pale green, glabrous, margin entire, aciliate. Leaves 3–5, alternate, basifixed; petiole 3–8.5 cm long, light green, glabrous; blade asymmetric, ovate, to 16 × 8 cm, succulent, apex acuminate, base cordate, basal lobes not overlapping, sinus to 2 mm deep, margin dentate, ciliate, upper surface dark green, glabrous, lower surface pale green, glabrous, veins palmate-pinnate, 6–8 veined from the base, with 2–4 secondary veins on the larger side, 1–3 secondary veins on the smaller side. Inflorescences 1–3 per stem, bisexual, axillary, erect, cymose, with 6 branches, bearing up to 32 staminate flowers and 32 pistillate flowers, protandrous; peduncle to 11 cm long, pale green, glabrous, bracts deciduous, elliptic to ovate, 4–6 × 1.5–4 mm, opaque, pale brown, glabrous, apex truncate, margin undulate, ciliate. Staminate flowers: pedicels to 10 mm long, glabrous; tepals 4, spreading, outer 2 ovate, 6–8 × 6–7 mm, apex rounded, white, glabrous, margin entire, ciliate, inner 2 oblanceolate, 7–8 × 2–3 mm, apex rounded, white to pink, glabrous, margin entire, aciliate; stamens ca 25, spreading, free, filaments 1.5–3 mm long, free, anthers elliptic, 0.5–1 × 0.4 mm, dehiscing via lateral slits, connectives extending to 0.2 mm, symmetrically basifixed. Pistillate flowers: pedicels to 27 mm long; bracteoles lacking; tepals 5, subequal, deciduous in fruit, spreading, obovate to broadly obovate, 4.5–9 × 2–7.5 mm, apex obtuse, white to pink, glabrous, margin entire, aciliate; ovary body ovoid, 4.5–7 × 4–6.5 mm, white to pink, glabrous, sub-equally 3-winged, wings triangular, 5.5–10.5 × 3.5–8.5 mm; 3-locular, placentae branches divided, bearing ovules on both surfaces; styles 3, yellow, free, ca 2 mm long, once-divided, stigmatic papillae in a spirally twisted band. Fruiting pedicel to 32 mm long. Fruit body ovoid, to 9 × 8 mm, drying brown, wings same shape as in ovary, expanding to 11 × 10 mm.

Proposed conservation assessment

Known from two populations within Peru, which are both close to rapidly expanding villages and vulnerable to agricultural and urban expansion. It is relatively common and frequently collected in Ecuador where it is known from ca 5 populations, and the total EOO of the species is ca 18 400 km 2. Given the species’ EOO, relatively few populations, and the threats to its Peruvian populations, we assess B. piurensis as Vulnerable (VU B1ab(iii)).

Identification notes

Begonia piurensis is most similar to B. velata L.B.Sm. &. B.G.Schub. (see below) but superficially resembles several species of B. sect. Cyathocnemis in that it is a large, upright herb with stems with elongate internodes and transversely ovate leaves. It differs from all species in this section in its staminate flowers with four tepals (vs two) and in having a tuber, but this is rarely recorded on herbarium labels. Note that while B. piurensis is tuberous we include it in the key as both a tuberous and non-tuberous species because this character is only noted on a single Peruvian specimen label.

Distribution and ecology

Known from Ecuador and Peru, including Piura Region in Peru. Known from northwest Peruvian relict montane forest at an elevation of 1200–1900 m a.s.l. ( Fig. 62B ). Begonia piurensis is a tuberous species, and it appears to die back to its tuber in the dry season before beginning to grow at the start of the wet season (January) before flowering and fruiting later in the wet season (April to June).

Figures

Fig. 62. Distribution of Begonia sect. Knesebeckia in Peru. A. B. brandbygeana L.B.Sm. & Wassh. (red) and B. parcifolia (blue). B. B. piurensis L.B.Sm. & B.G.Schub. (red) and B. velata L.B.Sm. & B.G.Schub. (blue). Black lines indicate country borders, grey lines indicate major administrative divisions, blue lines indicate rivers, and shading indicates elevation.