Begonia polypetala A.DC.

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 : 174-177

38. Begonia polypetala A.DC.

Figs 52D , 56

The Garden 14: 531 ( de Candolle 1878).

– Type: PERU • Cultivated, Jardin de M.M. Froebel, Zurich, Switzerland, Zurich, Switzerland; 1878; M.M. Froebel s.n.; lectotype: G [F neg. 24202], designated here.

Smith & Schubert (1941a: 198); Brako & Zarucchi (1993: 194); León & Monsalve (2006: 168); Tebbitt (2015: 480).

Etymology

Named for the unusually high number of tepals in the staminate flowers of the species, which is a common feature of the octopetala group of B. sect. Eupetalum .

Specimens examined

PERU • Nov. 1912; E.F. André K1069 ; K. – Piura Region: Prov. Huancabamba • Entre Palambla y Turmalina, ruta a Huancabamba ; 5°00′25″ S, 79°48′11″ W; 3100 m a.s.l.; 30 Apr. 1988; I. Sánchez V. 5122; CPUN, F • Dist. Canchaque; [5°22′ S, 79°35′ W]; 3 Jun. 1961; C. Acleto 225; USM • Carretera entre Canchaque y Huancabamba, km del 16 al 25 desde Canchaque ; [5°22′ S, 79°35′ W]; 17 Apr. 1987; C. Díaz y S. Baldeón M. 2403; F, MO [ MO-098013 ], USM • ibid.; 21 Mar. 1989; C. Díaz y H. Beltrán 3390; MO [ MO-098012 ], USM • Arriba de Canchaque , cerca al puente; [5°22′ S, 79°35′ W]; 1800–2000 m a.s.l.; 22 Mar. 1948; R. Ferreyra 3117; MO [ MO-2218585 ], US [ US00222147 ], USM • Above Canchanque on the Huancabamba pass ; 5°22′02″ S, 79°34′33″ W; 2028 m a.s.l.; 27 Jan. 2016; P.W. Moonlight & A. Daza 113; E [ E00885472 ], MO], MOL • ibid.; 5°22′39″ S, 79°33′32″ W; 2371 m a.s.l.; 27 Jan. 2016; P.W. Moonlight & A. Daza 119; E [ E00885469 ], MO [ MO-3254813 ], MOL • Dist. Canchaque, between Canchaque and Huancabamba; 5°22′ S, 79°34′43″ W; 1848–2063 m a.s.l.; 27 May 2015; M.C. Tebbitt & A. Daza 839; E, MOL • Dist. Canchaque, Paso Cuello del Inio ; [5°52′ S, 79°32′ W]; C.M. Ochoa 1796; CAS. – Cultivated • Jardin de M.M. Froebel, Zurich, Switzerland; Oct. 1877; M.M. Froebel s.n.; G.

Description

Acaulescent, tuberous herb, to 35 cm high. Tuber ellipsoid, 2–10 × 2.5 cm, with 1 growing points. Stipules persistent, broadly triangular, 5–10 × 5–12 mm, apex acute, opaque, dark brown, glabrous, margin entire, aciliate. Leaves 1–3, alternate, basifixed; petiole 6–27 cm long, pale green, densely hirsute; blade subsymmetric, ovate, to 36 × 26 cm, succulent, apex acuminate, base cordate, basal lobes not overlapping or overlapping, sinus to 7 mm deep, margin irregularly serrate, rarely with 1–5 triangular lobes on each side of the blade (W. Lewis et al. 17352), ciliate, upper surface pale green, pilose, lower surface very pale green, densely hirsute on the vein, pilose on the lamina, veins palmate but with one major vein, 5–8 veined from the base, with 2–4 secondary veins on the larger side, 2–4 secondary veins on the smaller side. Inflorescence 1, bisexual, axillary, erect, cymose, with up to 8 branches, bearing up to 4 staminate flowers and 4 pistillate flowers, protandrous; peduncle to 28 cm long, pale green, sparsely to densely hispid, bracts persistent, ovate, 12–24 × 4–10 mm, opaque, red, sparsely to densely hispid, apex acute to truncate, margin lacerate, ciliate. Staminate flowers: pedicels to 4.5 mm long, densely villous; tepals 6–8, projecting, subequal, 17–45 × 6–14 mm, apex acute, vivid red, glabrous to sparsely pilose on the outer surface, margin entire, aciliate; stamens ca 40, projecting, yellow, filaments 2–5 mm long, fused into an irregularly branching column, anthers ellipsoid, 1–2 × 0.5 mm, dehiscing via lateral slits, connectives not extending, symmetrically basifixed. Pistillate flowers: pedicels to 45 mm long; bracteoles lacking; tepals 5, subequal, persistent in fruit, projecting, 20–32 × 4–9 mm, apex acute, vivid red, glabrous to densely hirsute, margin entire, aciliate; ovary body ovoid, 8–10 × 4–7 mm, red, densely villous, unequally 3-winged, the largest wing triangular, 8–10 × 3–5 mm, the smallest marginal 1–2 mm wide; 3-locular, placentae branches divided, bearing ovules on both surfaces; styles 3, yellow, free, ca 7.5 mm long, irregularly 2- to 4-lobed, stigmatic papillae in a spirally twisted band. Fruiting pedicel to 62 mm long. Fruit body broadly ovoid, to 10.5 × 13.5 mm, drying brown, wings same shape as in ovary, the largest expanding to 10.5 × 13.5 mm, the smallest not expanding.

Proposed conservation assessment

Assessed as Critically Endangered (CR B1ab(iii)) by León & Monsalve (2006) because it was only known from a single locality and is rarely collected. Fieldwork in 2016 demonstrated the species is common at the type locality (ca 2500 individuals) and frequent collections from this locality suggest the population is stable. The species has now also been collected from a population further north (I. Sánchez V. 5122), extending the known EOO of B. polypetala to> 100 km 2. We assess B. polypetala as Endangered (EN B1ab(iii)).

Typification notes

The protologue of B. polypetala included a description and diagnosis written by A.P. de Candolle from cultivated material sent to Geneva by Mr Otto Froebel of Zurich ( de Candolle 1878: 531). The protologue includes an illustration of a staminate inflorescence, which is not sufficient to act as a lectotype. Geneva herbarium includes two sheets that could argued represent original material and are therefore candidates to act as lectotypes. The specimen is dated from October 1877 and includes a label written by A.P. de Candolle which can be translated as “not one of the species of the Prodromus ”, which demonstrates that this was considered an undescribed species by de Candolle. This specimen is accompanied by a letter from Froebel, dated 22 nd Oct. 1877, describing the specimen, its origins, and asking for an identification. The second specimen is labelled as “ Begonia polypetala A.DC. ” and is accompanied by two letters, which are of a little more impatient tone. By the time of the last letter, Frobel had visited Kew herbarium where he was unable to find any material matching his plant. Frobel also implies that he had sent “several” letters to de Candolle over the years requesting an identification. The label of the second specimen has the following written in de Candolle’s handwriting: “J’ai envoyé à Mr Froebel une description qu’il compte publier dans The Garden. Originaire du Pérou. Sept. Jardin de MM. Frobel à Zurich, Nov. 1878 ”. This implies de Candolle used this specimen to prepare his description of B. polypetala . The description of B. polypetala was published on the 14 th of December edition of The Garden, which implies an impressive turnaround between de Candolle describing the species and it appearing in print. This second specimen was photographed by the Field Museum (#24202) and has therefore been treated as the de facto type of B. polypetala . Accordingly, we designate this sheet as the lectotype of B. polypetala herein.

Identification notes

When in flower, identifying B. polypetala is straightforward as it is the only tuberous species of Begonia from Peru with red tepals or with acute apices. Identifying sterile individuals is more difficult, but the species’ indumentum of white, reflective hairs and leaves with acuminate apices are diagnostic.

Distribution and ecology

Endemic to Peru and Piura Region ( Fig. 52D ). Found in northwest Peruvian relict montane forests at an elevation of 1850–3100 m a.s.l. Begonia polypetala is fully deciduous and survives the dry season as a tuber. The flowers are produced during the wet season, which is from February to April. The species’ red flowers suggest it is pollinated by hummingbirds, but it provides no nectar reward and no such observations have been made. Much of the precipitation in the species’ range is condensation from clouds and the dense hairs on the species’ leaves and stems may help it trap this moisture.

Figures

Fig. 52. Distribution of the octopetala group of Begonia sect. Eupetalum (Lindl.) A.DC. in Peru and surrounding countries. A. B. anemoniflora Irmsch. (red) and B. tumbezensis Irmsch. (blue). B. B. octopetala L.Hér. subsp. octopetala (red) and B. octopetala subsp. ovatiformis Irmsch. (blue). C. B. pleiopetala A.DC. (red) and B. pseudopleiopetala Tebbitt (blue). D. B. polypetala A.DC. (red). Black lines indicate country borders, grey lines indicate major administrative divisions, blue lines indicate rivers, and shading indicates elevation.

Fig. 56. Begonia polypetala A.DC. A. Habit. B. Habitat. C. Staminate flower, front view. D. Staminate flower and inflorescence, side view. All photographs by P.W. Moonlight from P.W. Moonlight & A. Daza 119 in Huancabamba Province, Piura Region.