Begonia maculata Raddi, Mem. Moden.

Jacques, Eliane De Lima, Ribeiro, Maria Alice Martins & Tozin, Luiz Ricardo Dos Santos, 2023, Re-establishment of Begonia corallina Carrière (Begoniaceae) based on morphoanatomical evidence, Phytotaxa 609 (2), pp. 103-114 : 107-110

Begonia maculata Raddi, Mem. Moden. 18: 406. 1820. ( Fig 2 )

Type:— BRAZIL. G. Raddi s.n. (lectotype FI005293 ! designated here) .

Subshrub erect, 1.5–5 m tall. Cystoliths absent. Stems erect, branched at apex, decumbent, internodes 1–4.5 cm long, greenish, striate, glabrous. Stipules caducous, 2.5–4 × 0.5–0.6 cm, ovate, apex acuminate, margins entire, glabrous, membranaceous. Leaves simple, petioles (1.2–) 2–4.5 cm long, reddish, glabrous, leaf blades basifixed, 13.5–20(–21.5) × 4–6 cm, entire, transversely elliptic, asymmetrical, papyraceous, base cordate, margins entire to slightly undulate, apex acute, adaxial surface glabrous, shiny green, with rounded silvery spots, abaxial surface with microscopic glandular trichomes, greenish, occasionally vinaceous on the veins, venation actinodromous, 8–9 primary veins. Inflorescences 4–5-branched cymes, bearing up to 50 flowers, ca. 10 cm long (including the rachis), rachis ca. 4.5 cm long (up to ca. 12 cm when fruiting), glabrous, greenish on basal portions to pinkish distally. Bracts caducous, ca. 8 × 4 mm, ovate, apex acute, margins entire, glabrous. Staminate flower: pedicels 7–15 mm long, white, glabrous, tepals 4, external pair 11–16 × 10–17 mm, ovate, apex rounded, margins entire, white, membranaceous, glabrous, internal pair 6–11 × 2.5–4 mm, elliptic, apex acute to obtuse, margins entire, white, membranaceous, glabrous, stamens 24–32, 2.5–3 mm long, filaments 1–2.5 mm long, free, connective not projecting, obovate, anthers ca. 1 mm long (including connective), obovate, extrorse, yellow. Pistillate flower: pedicels 6–10 mm long, pinkish, glabrous, bracteoles 2, caducous, located alternately on the base of ovary, widely ovate to orbiculate, ca. 5 mm, white, tepals 5, white, unequal, 4 largest, 9–10 × 6–8 mm, 1 smallest ca. 7 × ca. 4 mm ovate to elliptic, apex acute to obtuse, margins irregularly crenate, membranaceous, glabrous, ovary 3-locular, ca. 14 × ca. 13 mm, white, indument, wings 4–6 mm wide, equal, plane, white, placentae bilamellate, ovules only outer surface of lamellae, stigmas 3, 3–5 mm long, bifurcate, branches spiraled, base flabelliform, stigmatic papillae only at base of stigma and the apex of branches, yellow. Capsule 15–17(– 20) × 15–21 mm (including wings), basally dehiscent, glabrous, light brown when mature, widely obovate, peduncles 7–10 mm long, glabrous, brown, wings 3, equal, plane, lunate, 5–6 mm wide, locular region 9–14 × 6–8 mm, obovate, glabrous, seeds oblong.

Etymology:—The specific epithet refers to spots on the leaves.

Phenology:—Flowering from April, September to January; fruiting from April, September to January.

Distribution and ecology: —This species is endemic of the Rio de Janeiro State. It grows in submontane forests, in a shady locality, with humus, humus-sandy or humus-clay soils ( Araújo et al. 1972), but in home gardens there is a widely cultivated or hybrid species similar in habit and form of leaf blades to Begonia maculata .

Provisional conservation assessment:—Although known only from small populations, Begonia maculata is provisionally assessed as Least Concern (LC) under IUCN Red List criteria (IUCN Standard and Petitions Committee 2019), as it has several populations with mature individuals in its range, occurring in federal and state conservation units.

Selected examined material:— BRAZIL Rio de Janeiro State. Rio de Janeiro Municipality: Parque Nacional da Tijuca. Estrada da Vista Chinesa, 10 September 1971, D. Sucre 7671 ( RB [ RB00053242 ]) ; Floresta da Tijuca , Serra da Carioca (Setor B), na Pedra da Proa , 28 January 2020, D. Nunes 377 ( RB [ RB01426667 ]) ; ibidem, Pedra Bonita — Pedra da Gávea , 03 December 2014, E. L. Jacques & J. Wesenberg 1910 ( RBR [ RBR00042499 ]) ; Restinga de Jacarepaguá, Formaçıes saxícolas do pared„o Sudoeste da Pedra de Itaúna, 15 September 1969, D. Sucre 5910 ( RB [ RB00053375 ]) ; formaç„o de encosta, Jacarepaguá , 900 m sm, 10 September 1971, D. Sucre 7649 ( NY [ NY01183904 ], RB [ RB00053391 ], RBR [ RBR00035871 ]) ; Morro do Caranguejo , no alto do Complexo Pav„o—Pav„ozinho, 4 September 2012, D. Pimenta & B. Esteves s.n. ( RB [00871995]) ; Parque Nacional da Tijuca, Floresta da Tijuca, estrada das Paineiras , 5 December 2012, L. Kollmann & C. N. Fraga 12562 ( MBML [ MBML045527 ], RB [ RB00787711 ]) ; Mata do Rumo, Reserva florestal do Jardim Botânico , 19 January 1969, D. Sucre 4458 ( RB [ RB00053380 ]) ; Pedra de Itaúna, Recreio dos Bandeirantes. Fragmento de restinga protegido pelo Condomínio Pedra de Itaúna , 8 April 2019, F. H. Nadal & C.D.M. Ferreira 62 ( RB [ RB01416340 ]). S „o Pedro da Aldeia, Parque Estadual Costa do Sol, Serra de Sapeatiba , 180m altitude, 23 April 2019, G. O. P. Guimarães 14 ( RBR [ RBR00045491 ]) ; 170 m altitude, 23 April 2019, G. O. P. Guimarães 15 ( RBR [ RBR00045492 ]).

Taxonomic notes:— Begonia maculata is a subshrub, with transversely elliptic leaf blades, with a shiny green, glabrous adaxial surface, with rounded silvery spots; an abaxial surface with microscopic glandular trichomes, obovate and extrorse anthers, ovary with bilamellate placentae, ovules only outer surface of lamellae, and widely obovate capsules. Due to its transversely elliptic blades, with rounded silvery spots B. maculata has been confused with a cultivar (or hybrid) of Begonia widely grown in home gardens. We just cannot say how this cultivar (or hybrid) was produced or how it came about. Probably they are the ‘Superba’ begonias, hybrids originally developed in California in 1926 from B. aconitifolia and ‘Lucerna’ ( Wall 1989), or ‘Lucerna Amazon’. Our examination of materials identified as B. maculata from other states of Brazil (i.e., not from Rio de Janeiro state) deposited in various herbaria indicates that all this material represents an ornamental similar to B. maculata . Begonia maculata can be distinguished from B. corallina by the color of flowers (white vs. coral red); the size of the external pairs of tepals on the staminate flowers (≤ 16 × ≤ 17 mm vs. ≥ 18 × ≥ 19 mm); the size of its tepals on the pistillate flowers (4 largest 9–10 × 6–8 mm, 1 smallest ca. 7 × ca. 4 mm vs. 2 largest ca. 17 × 13–15 mm, 3 smallest 12–16 × 7–10 mm); the arrangement of the ovules on the lamellae of the placentae (ovules only on the outer surface of lamellae vs. 1 lamella with ovules on the outer surface only and another with ovules on both surfaces) and the shape of its capsules (widely obovate vs. cordiform).

Figures

FIGURE 2. A–H. Begonia maculata Raddi. A, Habitat; B, Base of stem, showing plant branch; C, Leaf blades, showing rounded silvery spots on leaf surface; D, Habit; E, Staminate flowers; F, Pistillate flowers. A–B, D–F from G.O.P. Guimarães 14; C, from Jacques et al. 1910. Bars:A = 30 cm, B-C = 1 cm, D = 14 mm, E = 4 mm., F = 4.5 mm.