Begonia oblanceolata Rusby

Moonlight, Peter & Fuentes, Alfredo F., 2022, AN UPDATED CHECKLIST AND KEY TO THE SPECIES OF BOLIVIAN BEGONIA, INCLUDING ONE NEW SPECIES, Edinburgh Journal of Botany 79 (407), pp. 1-66 : 50-51

8.38. Begonia oblanceolata Rusby , Descr. S. Amer. Pl. 65 (1920).

– Type: Bolivia, [Cochabamba Department], Antahuacana , Espiritu Santo , 160 km al noreste de Cochabamba [17°4′S, 65°39′W], 750 m, vi 1909, O. Buchtien 2283 (lectotype NY [ NY00118638 ] designated in: Revista Univ. (Cuzco) 33(87): 83 (1944) by Smith, L.B. & Schubert, B.G.; isolectotype US [ US00115404 ]) .

L.B. Smith & B.G. Schubert, Revista Univ. (Cuzco) 33(87): 83 (1944); R.C. Foster, Contr. Gray Herb. 184: 138 (1958); D.C. Wasshausen et al. in P.M. JØrgensen et al. (eds), Cat. Bolivia, Monogr. Syst. Bot. Missouri Bot. Gard. 129: 385 (2013).

Caulescent herb, to 70 cm tall. Stem erect, rarely branching; internodes to 3 cm long, to 6 mm thick, succulent, green, glabrous. Stipules late deciduous to persistent, lanceolate, 10–16 × 3–6 mm, apex acuminate, translucent, brown, glabrous, margin entire, long-ciliate. Leaves> 5 per stem, alternate, basifixed; petiole 0.5–1.5 cm long, red, tomentose; blade asymmetrical, lanceolate, to 10.5 × 3 cm, membranaceous, apex long-acuminate, base rounded to cordate on the broader side, cuneate on the narrower side, margin serrulate, ciliate, upper surface green, glabrous, lower surface flushed red, pilose to tomentose, veins palmate-pinnate, secondary veins indistinct. Inflorescences> 3 per stem, either unisexual or bisexual and strongly protandrous, axillary, erect, cymose, with 2 branches, bearing up to 4 staminate flowers and/or 4 pistillate flowers; peduncle to 4.5 cm long, red, granular, bracts deciduous, ovate, 3.5–5 × 1.6–3 mm, colour unknown, glabrous, apex acute, margin serrulate, long-ciliate. Staminate flowers: pedicels to 17 mm long, glabrous; tepals 2, projecting, ovate, 13–15 × 8–11 mm, apex acuminate, base rounded, red, glabrous, margin entire, aciliate; stamens c.12, projecting, yellow, filaments 0.5 mm long, free, anthers linear, 1.5–3 × 1 mm, dehiscing via lateral slits, connectives not extended, symmetrically basifixed. Pistillate flowers: pedicels to 5 mm long; bracteoles 1, positioned directly beneath the ovary, lanceolate, 10–12 × 4–6 mm, apex acuminate, red, glabrous, margin lacerate, long ciliate; tepals 5, subequal, deciduous in fruit, spreading, elliptic, 12–17 × 2–5.5 mm, apex rounded, red, glabrous, margin entire, aciliate; ovary body obdeltoid, 12–13 × 7–8 mm, red, glabrous, unequally 3-winged, wings triangular, ascending, largest c.15 × 20 mm, smallest c.15 × 8 mm; 3-locular, placentation axillary, branches divided, bearing ovules on both surfaces; styles 3, yellow, free, 4–6.5 mm long, irregularly c.4 times-divided, stigmatic papillae in a spirally twisted band. Fruiting pedicel to 20 mm long. Fruit a capsule, body obdeltoid, to 13 × 8 mm, drying brown, wings same shape as in ovary, not expanding.

Distribution and ecology. Endemic to Bolivia and known from La Paz and Cochabamba Departments. Found in lower montane forest at an elevation of 750–1450 m, where it is typically collected within wet gullies and around small streams. Begonia oblanceolata has been collected in flower and fruit from March to July.

Etymology. Named for the species’ oblanceolate leaves.

Proposed IUCN conservation category. Begonia oblanceolata has an EOO of c. 1250 km 2 and is known from three populations within that area. None of these populations are within protected areas, so we assess the species as Endangered (EN), EN B1abiii, under IUCN criteria ( IUCN Standards and Petitions Subcommittee, 2019).

Additional specimens examined. BOLIVIA. sine loc., 1921, H.H. Rusby 445 ( NY). La Paz Department. Sud Yungas Province : Valley of río Boopi [Bopi], at unnamed village below Las Mercedes on road to Villa Barientos , 16°17′S, 67°20′W, 1000 m, 13 iii 1999, C.A. Pendry, R.T Pennington & C. Chumacero 566 ( E [ E00183993 ]) ; Basin of río Bopi , San Bartolome (near Calisaya), [c. 16°21′S, 67°16′W], 750–900 m, 1–22 vii 1939, B.A. Krukoff 10495 ( G [2], K, MO, NY) ; Espía , head of Bopi River , [c. 16°29′S, 67°18′W], 3500 ft, 8 viii 1921, H.H. Rusby 137 ( NY) ; ibid., 3500 ft, 1921, White ( NY). Cochabamba Department. Ayopaya Province: río Altamachi , 16°44′11′′S, 66°10′2′′W, 1450 m, 22 v 2004, E. Fernandéz & S. Altamirano 3852 ( MO) .

Notes. See Notes under Begonia comata for a discussion of whether the inflorescences of the two species are bisexual and strongly protandrous or unisexual.

Nomenclatural notes. The protologue of Begonia oblanceolata cites a type collection but no herbarium. Smith & Schubert (1944a) cited a duplicate in New York as the type, which is an effective lectotypification.

Identification notes. See Identification notes for Begonia comata .