Begonia occultata J.P.Allen & Moonlight, 2023

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 : 293-295

73. Begonia occultata J.P.Allen & Moonlight sp. nov.

urn:lsid:ipni.org:names:77323298-1

Figs 90A , 92

Diagnosis

Most similar to B. cremnophila Tebbitt but differing in its glabrous leaves (vs sparsely pilose to sparsely pubescent on the upper surface, pilose on the veins on the lower surface); its lanceolate bracts with an entire, aciliate margin (vs obovate with a denticulate, ciliate margin); and tepals that do not persist in fruit.

Etymology

The epithet derives from the Latin ‘ occultatus ’, meaning ‘hidden’ or ‘concealed’. It refers to the species’ patterned leaves, which are camouflaged against the forest floor.

Type

PERU – Puno Region: Prov. Sandia • Dist. San Pedro de Putina Punco, ca 7.5 km S of San Pedro de Putina on the road 34H to San Juan del Oro; 14°09′17″ S, 69°04′08″ W; 1068 m a.s.l.; 6 Feb. 2021; J.P. Allen 2; holotype: HUT [61143].

Description

Acaulescent, rhizomatous herb, to 32 cm high. Rhizome discoid to ellipsoid, 2.5–7 × 3–5 cm, with 1 growing point. Stipules persistent, triangular, 3–4.5 × 5.5–12 mm, apex acute, apiculate, translucent, green flushed red, glabrous, margin entire, aciliate. Leaves 2–4, alternate, basifixed; petiole 1.5–11 cm long, deep red, glabrous; blade asymmetric, transversely ovate, to 21.5 × 15.5 cm, succulent, apex acute, base cordate, basal lobes overlapping, sinus to 35 mm deep, margin repend, ciliate, upper surface dark green, the veins flushed pale green and flecked silver, often iridescent blue, glabrous, lower surface deep red, the veins flushed pale green, sparsely scabrous, veins palmate with one major vein, 6–8 veined from the base, with 2–4 secondary veins on the larger side, 1–3 secondary veins on the smaller side. Inflorescences 1–3, bisexual, axillary, erect, cymose, with 2 branches, bearing up to 6 staminate flowers and 3 pistillate flowers, protandrous; peduncle to 26.5 cm long, red, glabrous, bracts deciduous, triangular, 2–4.5 × 3.5–10 mm, translucent, pale green, glabrous, apex acute, margin entire, aciliate. Staminate flowers: pedicels to 13.5 mm long, glabrous; tepals 4, spreading, outer 2 broadly ovate, 4.5– 9.5 × 5–7.5 mm, apex obtuse, base rounded, white, glabrous, margin entire, aciliate, inner 2 oblanceolate, 4.5–7 × 2–4.5 mm, apex rounded, base cuneate, white, glabrous, margin entire to serrulate, aciliate; stamens ca 25, spreading, pale green, filaments ca 2.5 mm long, fused at the base, anthers obovoid, 1.2 × 0.8 mm, dehiscing via lateral slits, connectives not extended, symmetrically basifixed. Pistillate flowers: pedicels to 5.5 mm long; bracteoles lacking; tepals 5, subequal, deciduous in fruit, projecting, elliptic to ovate, 4–7.5 × 1.5–3.5 mm, apex obtuse, white, flushed pink outside, glabrous, margin entire, aciliate; ovary body broadly ovate, ca 3.5 × 2.5 mm, green flushed red, glabrous, unequally 3-winged, the largest wing triangular, ca 6 × 5 mm, smallest semi-circular, rib-like ca 1.5 mm wide; 3-locular, placentae branches divided, bearing ovules on both surfaces; styles 3, yellow, free, ca 2.5 mm long, once-divided, stigmatic papillae in a twice spirally-twisted band. Fruiting pedicel to 20 mm long. Fruit body ovoid, to 9.5 × 6.5 mm, drying brown, wings same shape as in ovary, the largest expanding to 13.5–20 mm, the smallest expanding to 4 mm wide.

Proposed conservation assessment

Known from a single population immediately adjacent to the main road through Sandia Province. During fieldwork in November 2020 and February 2021, ca 50 individuals were observed and a second population with ca 15 individuals was located ca 8 km southwest along the 34H at 14°12′57″ S 69°06′40″ W. Both populations are within 50 m of a main road and 300 m of built-up areas. Given the species’ small range and population size, and its proximity to a major road and human habitation, we assess B. occultata sp. nov. as Critically Endangered (CR B1ab(iii); C1+2a(i)).

Notes

The new species does not fit into any of the two large sections of tuberous Andean Begonia . It differs from species in B. sect. Eupetalum in its bifid rather than multifid styles, and from B. sect. Australes in lacking a stem. It is most similar to B. cremnophila , which is found ca 750 km to the southwest in Chuquisaca and Santa Cruz Departments, Bolivia. Begonia cremnophila was included in recent molecular phylogeny ( Moonlight et al. 2018) and was placed among a diverse group of Andean species that remain unplaced to section. We therefore treat B. occultata sp. nov. as unplaced to section.

Identification notes

Begonia occultata sp. nov. is difficult to distinguish from the southern Bolivian endemic species B. cremnophila (see Diagnosis). Within Peru, however, it is recognised as the only acaulescent and tuberous Begonia with no indumentum and a distinct apex to the leaf.

Distribution and ecology

Endemic to Peru and Puno Region ( Fig. 90A ). Found within lower montane forest at an elevation of 1050–1200 m a.s.l. Begonia occultata sp. nov. is tuberous and has been observed emerging from dormancy at the start of the wet season in September and flowering and fruiting in February. The tubers were collected on a moist bank in relatively seasonal montane forest where the patterned leaves are very inconspicuous, perhaps acting like camouflage.

Figures

Fig. 90. Distribution of the Begonia sect. Ignota in Peru and surrounding countries. A. B. bifurcata L.B.Sm. & B.G.Schub. (red), B. erythrothrix Tebbitt & Moonlight (red), and B. occultata J.P.Allen & Moonlight sp. nov. (green). B. B. speculum Moonlight & Tebbitt (red), B. thyrsoidea Irmsch., and B. urubambensis Tebbitt (green). Black lines indicate country borders, grey lines indicate major administrative divisions, blue lines indicate rivers, and shading indicates elevation.

Fig. 92. Begonia occultata J.P.Allen & Moonlight sp. nov. A. Habit. B. Leaf, adaxial surface. C. Leaf, abaxial surface. D. Fruit, side view. E. Staminate flower, front view. F. Staminate flower, side view. G. Pistillate flower, side view. All photographs taken by J.P. Allen from J.P. Allen 2 in Sandia Province, Puno Region.