Begonia andina Rusby

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 : 186-189

43. Begonia andina Rusby

Figs 59A , 60

Bulletin of the New York Botanical Garden 8: 108 ( Rusby 1912).

– Type: BOLIVIA – [La Paz Department] • Santa Barbara ; [14°44′ S, 68°37′ W]; 1525 m a.s.l.; 30 Aug. 1902; R.S. Williams 1566; lectotype: NY [ NY00112290 ], designated by Smith & Schubert (1944: 81); isolectotypes: BM [ BM001191441 ], K [ K000322980 ], US [ US00115238 ].

Smith & Schubert (1944: 81); Wasshausen et al. (2014: 383).

Etymology

Named for the Andes mountains.

Specimens examined

PERU – Puno Region: Prov. Sandia • Between San Juan del Oro and San Ignacio ; [14°10′ S, 69°04′ W]; 1200 m a.s.l.; 7 Jun. 1982; D.C. Wasshausen & A. Salas 1208; K [ K000374267 ], US [ US001286803 ]). BOLIVIA – La Paz Department: Prov. Franz Tamayo • Parque Nacional Madidi , Moxos , Fuertecillo ; 14°35′56″ S, 68°56′01″ W; 1900 m a.s.l.; 9 Nov. 2007; A. Arujo-Murakami & N. Chapi 4022; MO . – Prov. Bautista Saavedra • Madidi, Paujeyuyo ; 15°02′12″ S, 68°27′26″ W; 940 m a.s.l.; 15 Nov. 2003; A.F. Fuentes, L. Cayola, S. Whitehead, R. Cuevas & R. Cuevas 6151; LPB.

Description

Caulescent herb, to 120 cm high. Stem erect, branching; internodes to 11 cm long, to 7 mm thick, succulent, red to brown, densely stellate-tomentose. Stipules deciduous, ovate, 9–15 × 2.5–5 mm, apex acuminate, opaque, red, sparsely to densely stellate-tomentose, margin entire, aciliate. Leaves> 5 per stem, alternate, basifixed; petiole 1.5–9.5 cm long, red, densely stellate-tomentose; blade asymmetrical, transversely ovate, to 14.5 × 9 cm, succulent, apex short acuminate, base cordate, basal lobes not overlapping, sinus to 25 mm deep, margin entire to undulate, aciliate, upper surface dark green, sparsely stellate-tomentose, lower surface red, densely stellate-tomentose, veins palmate but with one major vein, 4–7 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 4 branches, bearing up to 16 staminate flowers and 16 pistillate flowers, protandrous; peduncle to 9 cm long, red, densely to sparsely stellate-tomentose, bracts deciduous, broadly deltoid, 2.5–8 × 1.5–8 mm, translucent, colour unknown, sparsely stellate-tomentose, apex truncate, margin lacerate, ciliate. Staminate flowers: pedicels to 19 mm long, densely stellate-tomentose; tepals 2, spreading, broadly ovate, 8–16 × 6–12 mm, apex rounded, white to pink, glabrous to sparsely stellate-tomentose, margin entire, aciliate; stamens ca 90, spreading, yellow, filaments 0.5–2 mm long, fused at the base into a torus, anthers oblong, 1–1.5 × 0.5 mm, dehiscing via lateral slits, connectives extended to 0.3 mm, symmetrically basifixed. Pistillate flowers: pedicels to 20 mm long, densely stellate-tomentose; bracteoles 2, positioned directly beneath the ovary, ca 7 × 6 mm, apex obtuse, translucent, colour unknown, glabrous, margin short-lacerate, ciliate; tepals 5, subequal, deciduous in fruit, projecting, lanceolate to ovate, 4.5–8 × 2–4 mm, apex obtuse, white to pink, glabrous to sparsely stellate-tomentose, margin entire to serrulate, aciliate to sparsely ciliate; ovary body ovoid to broadly ovoid, 2.5–7 × 2.5–6 mm, pale green flushed white to pink, sparsely to densely stellate-tomentose, unequally 3-winged, wings triangular, largest 2.5–11 × 1–10 mm, smallest 2.5–10 × 0.5–4 mm; 3-locular, placentae branches divided, bearing ovules on both surfaces; styles 3, yellow, free, 2.5–4 mm long, irregularly 4–10 times-divided, stigmatic papillae in spirally twisted bands. Fruiting pedicel to 32 mm long. Fruit body broadly obovoid, to 12 × 8 mm, drying brown, wings same shape as in ovary, the largest expanding to 16 × 18 mm, the smallest expanding to 13 × 10 mm.

Proposed conservation assessment

Known from three collections in La Paz Department, Bolivia, and a single collection in Puno Region, Peru, with a total EOO of ca 1800 km 2. The species’ range has a very high percentage of remaining forest cover but is under pressure from small-scale subsistence farming and cocoa production. Its few collections suggest B. andina is rare, and we were unable to locate it during fieldwork to Sandia Province in September 2020. We assess B. andina as Endangered (EN B1ab(iii)).

Identification notes

Begonia andina is a simple species to determine on account of the densely tomentose stellateindumentum on its stems, petioles, and the underside of its leaves, which distinguishes it from all other Peruvian Begonia species. It may be confused with B. unilateralis , which also has a dense indumentum but one consisting of peltate scales. In both species, the indumentum can rub off but is usually present on most of the plant. The two species also differ in their leaf margins, which are entire to undulate in B. andina and serrate in B. unilateralis , and in the stipules and bracts, which are deciduous in B. andina and persistent in B. unilateralis .

Distribution and ecology

Known from Peru and Bolivia. In Peru, it has been collected in Puno Region ( Fig. 59A ) and is found in lower montane forest at an elevation of 1200 m a.s.l.

Figures

Fig. 59. Distribution of Begonia sect. Hydristyles A.DC. in Peru and surrounding countries.A. B. andina Rusby (red). B. B. unilateralis Rusby (red). Black lines indicate country borders, grey lines indicate major administrative divisions, blue lines indicate rivers, and shading indicates elevation.

Fig. 60. Begonia andina Rusby. A. Habit (inset, stellate hair). B. Staminate flower, front view. C. Staminate flower, side view. D. Pistillate flower, front-side view. Illustration by Anna Dorward from D.C. Wasshausen & A. Salas 1208 (US).