Begonia tumbezensis Irmsch.

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 : 179-180

40. Begonia tumbezensis Irmsch.

Fig. 52A

Botanische Jahrbücher für Systematik, Pflanzengeschichte und Pflanzengeographie 76: 74 ( Irmscher 1953).

– Type: PERU – Tumbes Region: [Prov. Contralmirante Villar] • Mountains S.E. of Hacienda la Choza ; [4°10′ S, 80°47′ W]; 900–1000 m a.s.l.; A. Weberbauer 7685; lectotype: F [ V0042335 F, photo P, illustration B [ B100186585 ]], designated here; epitype: US [ US00222324 ], designated here; isolectotype: B ex F [ B100186589 ] • Tumbes Region, mountains S.E. of Hacienda Chicama ; [4°10′ S, 80°47′ W]; 800–900 m a.s.l.; 19–24 Feb. 1927; A. Weberbauer 7646; syntypes: F [ V0042334F , V0042333F ], B ex F [ B100186588 ].

Brako & Zarucchi (1993: 195); León & Monsalve (2006: 169); Tebbitt (2015: 480).

Etymology

The type collection was made by Augusto Weberbauer in Tumbes Region, and the species is named for its type locality.

Selected specimens examined

PERU – Tumbes Region: Prov. Tumbes • East of Hacienda Chicama ; [4°10′ S, 80°47′ W]; A. Weberbauer 7641; B . – Cajamarca Region: Prov. Contumazá • Entre Chilete y El Rupe, al oeste de la carretera Chilete-Contumazá; [7°18′ S, 78°49′ W]; 1700 m a.s.l.; 19 Feb. 1987; I. Sánchez V. 4230; CPUN, MO [MO-2218588] . – La Libertad Region: Prov. Trujillo • Cerro Campana, ca 16 km N of Trujillo on Pan-American highway; [7°59′ S, 79°06′ W]; 300–700 m a.s.l.; 10 Oct. 1986; M. O. Dillon, J. Santisteban & B. León 4660; F [2: V0078830 F, V0078831 F], HUT • Cerro Chiputur; [8°10′ S, 78°57′ W]; 400–500 m a.s.l.; 25 Jul. 1948; N. Angulo 829; HUT • Virú; [8°19′ S, 78°48′ W]; 525 m a.s.l.; 3 Sep. 1949; N. Angulo 1102; HUT • ibid.; 420 m a.s.l.; 18 Aug. 1949; N. Angulo 1113; HUT .

Description

Acaulescent, tuberous herb, to 35 cm high. Tuber globose, 1.5–2.5 × 1.5–2 cm, with 1 growing point. Stipules persistent, triangular, 5–8 × 4–6 mm, apex acute, opaque, dark brown, glabrous, margin entire, aciliate. Leaves 2–5, alternate, basifixed; petiole 4.5–35 cm long, green, sparsely to densely villous; blade subsymmetric, reniform, to 21 × 21.5 cm, succulent, apex indistinct and rounded to obtuse or short-acuminate, base cordate, basal lobes overlapping or not overlapping, sinus to 8 cm deep, margin serrate, often with 2 to 5 triangular lobes, ciliate, upper surface green, glabrous, lower surface green, densely villous to glabrous, veins palmate, 4–8 veined from the base. Inflorescences 1–3, bisexual, axillary, erect, cymose, with 4 branches, bearing up to 4 staminate flowers and 2 pistillate flowers, protandrous; peduncle to 35 cm long, sparsely to densely villous, bracts persistent, ovate, 8–12 × 4–6 mm, opaque, white, glabrous, apex obtuse, margin entire, aciliate. Staminate flowers: pedicels to 4.5 cm long, sparsely villous; tepals 4, spreading, outer 2 broadly-ovate, 10–25 × 12–32 mm, apex rounded, white, sometimes flushed pink at the apex, glabrous, margin entire to serrate towards the apex, ciliate, inner 2 ovate to obovate, 8–24 × 6–21 mm, apex rounded, white, glabrous, margin entire to rarely serrate towards the apex, aciliate; stamens> 50, spreading, yellow, filaments 3–5 mm long, free, anthers ovoid, 0.5–0.8 × 0.3 mm, dehiscing via lateral slits, connectives not extended, symmetrically basifixed. Pistillate flowers: pedicels to 30 mm long; bracteoles lacking; tepals 5, subequal, persistent in fruit, spreading, the largest ovate, 10–13 × 6–10 mm, apex rounded, white, sometimes flushed pink at the apex, glabrous, margin entire to serrate, aciliate, the smallest ovate, 9–10 × 4–6 mm, apex rounded, white, glabrous, margin entire, aciliate; ovary body obovoid, 7–12 × 6–13 mm, glabrous, unequally 3-winged, largest wing rectangular, ca 15 × 8 mm, smallest wings marginal 1–2 mm wide; 3-locular, placentae branches divided, bearing ovules on both surfaces; styles 3, yellow, free, 3–4.5 mm long,> 3 times-divided, stigmatic papillae in a spirally twisted band. Fruiting pedicel to 30 mm long. Fruit body obovoid, to 10 × 15 mm, drying brown, largest wings same shape as in ovary, expanding to 20 × 35 mm, the smallest expanding to a triangular wing, to 13 × 11 mm.

Proposed conservation assessment

Assessed by León & Monsalve (2006) as Data Deficient (DD). Now known from an EOO of almost 40 000 km 2, which includes the well-protected Cerro Campana in Trujillo Region and the Cerros de Amotape National Park in Tumbes Region, as well as protected areas in Ecuador.We assess B. tumbezensis as Least Concern (LC).

Typification notes

The protologue of B. tumbezensis cited material of two collections held in Chicago (F): A. Weberbauer 7646 and 7685 ( Irmscher 1953: 74). Irmscher also sketched both specimens and removed material, which he deposited in Berlin herbarium. It is appropriate to choose a lectotype from the material of these two collections held in F. The best candidate of these specimens is A. Weberbauer 7685 (V0042335F) because it includes developing fruits, and we designate this specimen as the lectotype. Unfortunately, Irmscher removed all staminate flowers from this sheet and characters of the staminate flowers are key for identifying B. tumbezensis . It is therefore appropriate to designate an epitype. A duplicate of the lectotype held at US herbarium ( US 00222324) is the ideal candidate because it includes staminate flowers, pistillate flowers and fruits so we assign this sheet as the epitype of B. tumbezensis . This also ensures all the type material of B. tumbezensis is derived from a single gathering.

Identification notes

Most collections of B. tumbezensis have been incorrectly named as B. octopetala . The two species are trivial to distinguish in flower due to the number of tepals on the staminate flower (4 tepals in unequal pairs in B. tumbezensis ; at least 6 subequal tepals in B. octopetala ) and the serrated outer tepals of the staminate flowers of B. tumbezensis (vs entire).

Distribution and ecology

Known from Peru and Ecuador. Within Peru, collected within La Libertad, Cajamarca, and Tumbes Regions ( Fig. 52A ). It is found most frequently in Lomas formations surrounding Trujillo, but also in dry forests and scrubland in Cajamarca and Tumbes Regions. All these areas have a distinct dry season and B. tumbezensis dies back to a tuber during the dry season and flowers in the wet season, which is July to October in Lomas formations and from February in Dry Forests.

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.