Begonia joshii Moonlight

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 : 153-155

32. Begonia joshii Moonlight

Figs 1B , 2G , 7D , 48A , 50

Edinburgh Journal of Botany 77 (1): 149 ( Moonlight et al. 2020).

– Type: PERU • Cultivated collection; 29 Nov. 2019; P.W. Moonlight 1277; holotype: USM; isotype: E [ E00884943 ]; cultivated at the Royal Botanic Garden Edinburgh from seed collected in the wild (accession no 20180923: Amazonas Region: Prov. Chachapoyas: trail over Puente La Florida from km 278 of Pedro Ruiz Gallo-Bagua Grande road , ca 4 km from trail head, 5°54′13″ S, 78°4′33″ W, 2064 m a.s.l.; 3 Jul. 2018; P.W. Moonlight 1253).

Etymology

Named for Josh Allen, who sent photographs of the species to the author.

Specimens examined

PERU – Amazonas Region: Prov. Chachapoyas • trail over Puente La Florida from km 278 of Pedro Ruiz Gallo–Bagua Grande road , ca 4 km from trail head; 5°54′ 17”S, 78°4′42”W; 1441 m a.s.l.; 3 Jul. 2018; P.W. Moonlight 1251; E, USM • ibid.; 1469 m a.s.l.; 5°54′14”S, 78°4′40”W; 3 Jul. 2018; P.W. Moonlight 1252; E, USM • ibid.; 1520 m a.s.l.; 5°54′13”S, 78°4′33”W; 3 Jul. 2018; P.W. Moonlight 1253; E, USM. – Cajamarca Region: Prov. Chota • Chalamarca ; [6°30′ S, 78°31′ W]; 2400 m a.s.l.; 29 Dec. 2012; L. García Llatas 9594; USM. – Prov. Celendín • El Porvenir , al SE de la Quintilla; [6°58′ S, 78°06′ W]; 2750 m a.s.l.; 25 Feb. 1986; I. Sánchez V. 3991; CPUN.

Description

Acaulescent, tuberous herb, to 30 cm high. Tuber sub-globose, 1.5–4 × 1.5–5 cm, with 1 growing point. Stipules late deciduous, lanceolate, ca 8 × 5 mm, apex acute, apiculate, translucent, white to pink, glabrous, margin entire, aciliate. Leaves 1–5, alternate, basifixed or peltate; petiole to 18 cm long, pink to red, glabrous; blade subsymmetric, orbicular, to 10.5 × 8.5 cm, succulent, apex rounded, base peltate and notched to cordate, basal lobes overlapping to not overlapping, sinus to 15 mm deep, margin irregularly crenate, aciliate, upper surface green, glabrous, lower surface very pale green, glabrous, veins peltate or palmate, 6–8 veined from the base. Inflorescences 1–3, bisexual, axillary, erect, a dichasial or monochasial cyme, with 1 branch, bearing up to 4 staminate flowers and 2 pistillate flowers, protandrous; peduncle to 28 cm long, white to pink, glabrous, bracts late deciduous, lanceolate, ca 6 × 3.5 mm, translucent, pale green, glabrous, apex obtuse, margin entire, aciliate. Staminate flowers: pedicels to 28 mm long, glabrous; tepals 4, spreading, outer two narrowly ovate, 7–12 × 4–11 mm, apex rounded, white, glabrous, margin entire, aciliate, inner two oblanceolate, 10–11 × 6 mm, apex truncate, sometimes notched, white, glabrous, margin entire, aciliate; stamens 11–16, projecting, yellow, filaments ca 1 mm long, united into a 1–2 mm column, anthers linear, ca 2 × 1 mm long, dehiscing by lateral slits, connectives not extending, symmetrically basifixed. Pistillate flowers: pedicels to 30 mm long; bracteoles 2, positioned directly below the ovary, elliptic to narrowly lanceolate, 1–1.5 × 0.5 mm, apex rounded, translucent, pale green, glabrous, margin entire, aciliate; tepals 5, persistent in fruit, spreading, the largest oblanceolate to obovate, ca 11 × 9 mm, apex truncate to rounded, white, glabrous, margin entire, aciliate, the smallest obovate, ca 9 × 5 mm, apex truncate to rounded, white, glabrous, margin entire, aciliate; ovary body ovoid, 8–9 × 5–7 mm, light green, glabrous, unequally 3-winged, wings triangular, largest 10–13 × 9–14 mm, smallest 5–6 × 9–11 mm; 3-locular, placentae branches entire, bearing ovules on both surfaces; styles 3, yellow, free, 2–3 mm long, 4-lobed, stigmatic papillae in a band around the lobes. Fruiting pedicel to 25 mm long. Fruit body globose, to 6 × 6 mm, drying brown, wings same shape as in ovary, expanding to 25 mm tall.

Proposed conservation assessment

Assessed by Moonlight et al. (2020) as Data Deficient (DD) because it was not possible to survey similar habitats close to the type locality for the species’ presence. We have since identified two further populations of B. joshii in Cajamarca Region and visited so feel confident in suggesting a conservation assessment. The species is known from <5 locations and has an EOO of <5000 km 2. The population in Amazonas Region and the population in Celendin Province, Cajamarca Region both had> 2500 individuals when visited in July 2018 and December 2021, respectively. However, all three known populations are within degraded seasonally dry tropical forest habitats. We assess B. joshii as Endangered (EN B1ab(iii)).

Notes

We expand the earlier circumscription of B. joshii to include two populations in Cajamarca Region, which have basifixed leaves much more frequently than the populations in Amazonas. The species remains distinct from B. neoharlingii and B. geraniifolia on account of lack of an above-ground stem; and its thicker, more succulent leaves that always lack lobes. It further differs from B. geraniifolia in its bracteolate pistillate flowers.

Identification notes

The only tuberous species of northern Peruvian Begonia with leaves that are circular in outline and lack any lobes.

Distribution and ecology

Endemic to Peru and known from Amazonas and Cajamarca Regions ( Fig. 48A ). Found in dry forests at an elevation of 1441–2600 m a.s.l. Begonia joshii has been collected on vertical rock faces, which are wet in the dry season. The species is tuberous and dies back in the dry season to its tuber.

Figures

Fig. 1. Leaf margins of Peruvian Begonia. A. Entire, aciliate margins (B. stenotepala A.DC.). B. Crenate, aciliate margins (B. joshii Moonlight). C. Denticulate, ciliate margins (B. acerifolia Kunth). D. Irregularly double-dentate, ciliate margins (B. obtecticaulis Irmsch.). E. Serrulate, aciliate margins (B. glauca (Klotzsch) Ruiz & Pav. exA.DC.). F. Serrate, ciliate margins (B. foliosa Kunth). Photographs taken by D.A. Purvis & P.W. Moonlight in the living collections of the Royal Botanic Garden Edinburgh.

Fig. 2. Venation in Peruvian Begonia. A. Pinnate venation (B. yaracuyensis Moonlight). B. Pinnate venation, 3-veined from the base (B. glabra Aubl.). C. Palmate-pinnate venation (B. obtecticaulis Irmsch.). D. Palmate venation with one primary vein (B. stenotepalaL.B.Sm. & B.G.Schub.).E. Palmate venation (B. lamolina Moonlight). F. Peltate venation with one primary vein (B. acerifolia Kunth.). G. Peltate venation (B. joshii Moonlight). Primary veins are shown in white, secondary veins from the petiole insertion in blue, and secondary veins from the primary veins in green. Photographs taken by D.A. Purvis & P.W. Moonlight in the living collections of the Royal Botanic Garden Edinburgh.

Fig. 7. Placentation in Peruvian Begonia. A–D. Axillary placentation with undivided branches. E–H. Axillary placentation with divided branches. A. B. buddleiifolia A.DC. B. B. foliosa Kunth. C. B. glabra Aubl. D. B. joshii Moonlight. E. B. albomaculata C.DC. F. B. rossmanniae A.DC. G. B. bracteosa A.DC. H. B. pleiopetala A.DC. Photographs taken by D.A. Purvis & P.W. Moonlight in the living collections of the Royal Botanic Garden Edinburgh.

Fig. 48. Distribution of Begonia sect. Eupetalum (Lindl.) A.DC. in Peru and surrounding countries. A. B. geraniifolia Hook. (red) and B. joshii Moonlight (blue). B. B. neoharlingii L.B.Sm. & Wassh. (red) and B. weberbaueri Irmsch. (blue). Black lines indicate country borders, grey lines indicate major administrative divisions, blue lines indicate rivers, and shading indicates elevation.

Fig. 50. Begonia joshii Moonlight. A. Habit. B. Leaf, adaxial surface. C. Leaf, abaxial surface. D. Inflorescence. E. Staminate flower, front view. F. Staminate flower, side view. G. Smallest tepal of staminate flower. H. Largest tepal of staminate flower. I. Androecium, side view. J. Pistillate flower, front view. K. Pistillate flower, side view. L. Cross section of ovary. M. Smallest tepal of pistillate flower. N. Largest tepal of pistillate flower. O. Pistils, side view. All photographs taken by D.A. Purvis in the living collections of the Royal Botanic Garden Edinburgh (Accession 20180923, grown from seeds collected as part of P.W. Moonlight 1253). Reproduced from Moonlight et al. (2020), with the permission of Edinburgh Journal of Botany.