Begonia ludwigii Irmsch.

52. Begonia ludwigii Irmsch.

Fig. 65B

Bibliotheca Botanica 116: 113 (Irmscher 1937).

– Type: ECUADOR – Prov. Chimborazo • valle del río Chanchan, Naranjapata; 530 m a.s.l.; 26 Sep. 1933; L. Diels 1204; holotype: B [B100089160, B100089161, photo US].

Smith & Schubert (1952: 38); Smith & Wasshausen (1986: 43); Tebbitt et al. (2015: 347); Quintana & León-Yáñez (2011: 199); Esquerre-Ibañez & Tebbitt (2018: 437).

Begonia compacticaulis Irmsch., Botanische Jahrbücher für Systematik, Pflanzengeschichte und Pflanzengeographie 74: 612 (Irmscher 1949).

– Type: ECUADOR – Prov. Chimborazo • Huigra; Jul. 1923; A.S. Hitchcock 20315; holotype: US [US00115288]; isotype: NY [NY00842224].

Smith & Wasshausen (1979: 244, 1986: 38); Quintana & León-Yáñez (2011: 198); Tebbitt et al. (2015: 348).

Begonia ecuadorensis auct. non Buxton: hort. ex Everett, Journal of the New York Botanical Gardens 41: 4 (Everett 1940).

Tebbitt et al. (2015: 348).

Begonia rigida auct. non Linden ex Regel: A.Clarke, The Begonian 14: 150 (Clarke 1947).

Carrell (1950: 128); Tebbitt et al. (2015: 348).

Begonia griseocaulis auct. non Irmsch.: L.B.Sm. & B.G.Schub., Memoirs of the New York Botanical Garden 8 (1): 38 (Smith & Schubert 1952).

Smith & Wasshausen (1979: 244); Tebbitt et al. (2015: 348).

Etymology

German botanist Ludwig Diels collected the type specimen of the species, which is named in his honour.

Specimens examined

PERU – Piura Region: Prov. Huancabamba • Dist. Huarmaca, entrada a Limón de Porcuya; 5°53′07″ S, 79°32′04″ W; 1541 m a.s.l.; 12 May 2017; B. Esquerre 156; HUT. – Cajamarca Region: Prov. San Miguel • Dist. La Florida, alrededores de La Florida; 6°53′37″ S, 79°07′08″ W; 1480 m a.s.l.; 28 May 2015; M.C. Tebbitt & A. Daza 846; E, MOL. – Prov. Chota • Llama; [6°31′ S, 79°07′ W]; 2000 m a.s.l.; 6 Apr. 2012; L. Garcia Llantas 8591; USM. – Lambayeque Region: Prov. Lambayeque • Dist. Salas, entre Kerguer y Hualanga; 6°11′03″ S, 79°29′57″ W; 1450 m a.s.l.; 12 May 2017; B. Esquerre 155; HUT • Dist. Inkawasi, cerca de Moyán; 6°17′25″ S, 79°26′19″ W; 1420 m a.s.l.; 10 Jan. 2018; B. Esquerre 164; HUT.

Description

Caulescent herb, to 100 cm high. Stem erect, rarely branching; internodes to 9 cm long, to 12 mm thick, succulent, becoming hardened at maturity, grey-brown, glabrous. Stipules deciduous, triangular, 5–12 × 3–7 mm, apex acute, translucent, brown, glabrous, margin entire, aciliate. Leaves 1–5 per stem, alternate, basifixed; petiole to 16 cm long, pale green, glabrous but with a ring of squamous hairs at the apex of the petiole; blade sub-symmetric, orbicular in outline, to 29 × 32 cm, succulent, apex acuminate, base cordate, basal lobes not overlapping, sinus to 75 mm deep, margin serrate, with 5–7 irregular, sinuous lobes around the lamina, ciliate, upper surface dark green, glabrous, lower surface pale green, veins white flushed red, glabrous, veins palmate, 5–7 veined from the base. Inflorescences 1–3 per stem, bisexual, axillary, erect, cymose, with 3 branches, bearing up to 16 staminate flowers and 16 pistillate flowers, protandrous; peduncle to 25 cm long, pale green, glabrous, bracts deciduous, ovate, 7–10 × 4–5 mm, opaque, white, glabrous, apex acute to obtuse, margin entire, aciliate. Staminate flowers: pedicels to 20 mm long, glabrous; tepals 4, spreading, outer 2 broadly ovate, 7–12 × 6–15 mm, apex rounded, white, glabrous, margin entire, aciliate, inner 2 oblanceolate, 8–14 × 3–6 mm, apex rounded, white, glabrous, margin entire, aciliate; stamens ca 50, spreading, yellow, filaments 3–4 mm long, fused at the base, anthers obovoid, ca 0.75 × 0.5 mm long, dehiscing via lateral slits, connectives extending to 0.1 mm, symmetrically basifixed. Pistillate flowers: pedicels to 20 mm long; bracteoles 2, positioned directly beneath the ovary, ovate, 4–7 × 2–5 mm, apex obtuse, opaque, white, glabrous, margin entire, aciliate; tepals 5, subequal, persistence in fruit, spreading, oblanceolate to broadly ovate, 3.5–9 × 1.5– 10 mm, apex obtuse to rounded, white, glabrous, margin entire, aciliate; ovary body obovoid, ca 3.5 × 2.5 mm, white, glabrous, sub-equally 3-winged, wings marginal, 0.5–2 mm wide; 3-locular, placentae branches divided, bearing ovules on both surfaces; styles 3, yellow, free, 2–4 mm long, once-divided, stigmatic papillae in a spirally twisted band. Fruiting pedicel to 10 mm long. Fruit body obovoid, to 9 × 8 mm, drying brown, wings becoming triangular, expanding to 9 × 5 mm.

Proposed conservation assessment

Assessed as Vulnerable (VU B2ab(iii)) by Quintana & León-Yáñez (2011), who also assessed its recent synonym B. compacticaulis Irmsch. as Vulnerable (VU B1ab(iii)). Esquerre-Ibañez & Tebbitt (2018) were the first to record B. ludwigii in Peru and recommended the species retained its Vulnerable status as only one of the species’ Peruvian populations is in a protected area. This contradicts the IUCN criteria, as the combined Peruvian and Ecuadorian range of the species has an EOO of ca 28 000 km 2 and it is known from more than 10 locations. We reassess B. ludwigii as Least Concern (LC).

Typification notes

The protologue of B. ludwigii cites L. Diels 1204 held in B as type material (Irmscher 1937: 113). There are two sheets of this collection in B and as they labelled as sheets A (B100089160) and B (B100089161) they can be treated as two separate sheets of the same holotype.

Identification notes

Begonia ludwigii and B. huancabambae sp. nov. are the two only Peruvian Begonia species with a ring of squamous hairs at the apex of the petiole and both are relatively large species with thick, succulent stems and lobed leaves. Begonia ludwigii can be distinguished from B. velata by the prominent petiole scars on its stems and by the irregularly sinuous lobes around its leaf margins (the lobes of B. velata are regularly triangular).

Distribution and ecology

Known from Ecuador and Peru, and in Peru it has been collected in Piura, Cajamarca, and Lambayeque Regions (Fig. 65A). Found in northwest Peruvian montane forest at an elevation of 1420–1550 m a.s.l. Begonia ludwigii most likely drops its leaves in the dry season.