Begonia oxyphylla A.DC., Ann. Sci. Nat., Sci.

Jacques, Eliane De Lima, 2018, Re-establishment of Begonia oxyphylla (Begoniaceae), a species from the coastal forests of Brazil, Phytotaxa 381 (1), pp. 22-26 : 22-25

Begonia oxyphylla A.DC., Ann. Sci. Nat., Sci. 4, Bot. 11: 140. 1859. ( Figs. 1–2 )

Lectotype (designated here):— BRAZIL. [Rio de Janeiro]: “in umbrosis ad rivos Basso di Serras [= Serra de Itaguaí], Pohl. – Serra de Mocas [= Serra de Macacu ]. Schott.” ( W49658 !).

Subshrub, erect, terrestrial, ombrophilous, ca. 2 m tall, cystoliths present, most easily seen in hyaline structures. Stem with internodes greenish in their proximal regions, rust colored distally, 1–4 (–10.5) cm long, puberulous to glabrescent, with shortly spinous stellate trichomes. Leaves simples, petioles cylindrical, greenish in the proximal region, 0.5–1.3 (–1.7) cm long, ferruginous distally, puberulous throughout, stipules early-deciduous, navicular, 5–6 (–8) × 1.5–2 mm, adaxial surface hirsute, abaxial surface tomentose-ferruginous, leaf blades elliptic, slightly bifacial, papyraceous, (12.5–) 14–20.5 × (2.5–) 3–5.2 cm, adaxial face with shortly spinous stellate trichomes, sparsely pubescent to glabrescent, abaxial face with shortly spinous stellate trichomes, sparsely pubescent on much of lamina but dense on the principal veins, margins serrated, apex acuminate, base obtuse, slightly asymmetrical, venation craspedodromous. Inflorescence 8.5–15 cm long (including the rachis), rachis 5–9 cm long. Male flowers ca. 7 mm long; pedicel 3–4 mm long, puberulous; tepals 4, reflexed at anthesis, external tepals cochlear, widely obovate, white, 3–3.2 × 2–2.5 mm, pilose, internal tepals obovate, white, 2–2.2 × ca. 1 mm, glabrous, stamens 36, united, androphore ca. 1 mm long, anthers rimose, basifixed, obovate, yellow, extrorse, ca. 3 mm long, connectives very shortly projecting. Female flowers ca. 3 mm long; pedicel 1–2 mm long; bracteoles 2, triangular, 0.03–0.05 × 0.03–0.05 mm, margins entire to serrated; tepals 5, rarely 6, white, 1.5–3 × 0.05–1 mm, puberulous on the lower third, ovary 3–locular, stigmas 3, ca. 1.2 mm long, hypanthium ca. 1.5 mm long, densely pilose, placentae entire. Capsules oblate to transversely elliptic, 6–10 × 5–6 (–11) mm, pedicels ca. 4 mm long. Seeds oblong, brown, 300–355 μm long.

Distribution and habit: —The species is restricted to the southern region of Rio de Janeiro State, Brazil. It grows in shady localities, especially near watercourses, from submontane forests at an elevation of 120 to 790 m.

Phenology: —Flowering from December–February; fruiting from April–November.

Material examined: — BRAZIL: s. loc., s.d., s. col. ( W49659 ). Rio de Janeiro: Itaguaí, estrada do Caçador, Sítio de D. Dora Sá Freire Basílio, 8 January 1991, J. P. P. Carauta et al. 6259 ( GUA). Mendes, Fazenda São José das Paineiras, Centro Marista, 22°30’41,5”S, 43°45’27,3”W, 530 m, 5 December 2014, E. L. Jacques & J. Wesenberg 1917 ( RBR) ; ib., 22°30’34,5”S, 43°45’20”W, 575 m, 5 December 2014, E. L. Jacques & J. Wesenberg 1919 ( RBR). Miguel Pereira, Conceição, 22°27’53”S, 43°27’46”W, 29 June 2013, M. S. Wängler & V. S. Ferreira 1351 ( RB) ; ib., Parque Municipal da Rocha Negra, 647 m, 20 November 2013, E. L. Jacques J. Wesenberg et al. 1869, 1870 ( RBR). Nova Iguaçu, Jaceruba, Floresta Protetora da CEDAE, Serra da Bandeira, 17 October 1977, F. S. Vianna et al. 1200 ( GUA). Paracambi, Parque Natural Municipal do Curió , 5 June 2008, A. V. S. Couto & E. L. Jacques 44 ( RBR) ; ib., 17 Abril 2009, Alunos Curso Eng. Florestal 9 ( RBR) ; ib., 22°35´44,8” S, 43°42´27” W, 129 m, 4 November 2011, E. L. Jacques 1784 ( RBR) ; ib., 23 K 0633055 UTM 7599497, 79 m, 14 July 2012, M. P. Palmeiro & E. L. Jacques 01, 02 ( RBR) ; ib., 1 February 2013, E. L. Jacques 1861, 1862 ( RBR) ; ib., 22°35´47,9” S, 43°42´17,9” W, 163 m, 12 March 2014, E. L. Jacques, C. F. Andrade & J. Santos 1891 ( RBR). Rio das Flores, Fazenda Santa Genoveva, 7 October 1971, 500–600 m, D. Sucre 7777 ( RB). Vassouras, Morro Azul, 1944, F. S. Vianna s.n. ( RB 67986 ) ; ib., 26 June 1944, F. S. Vianna 504 ( RB) ; Sítio da Lua , 22°26’43,3”S, 43°32’18,5”W, 790 m, 26 January 2014, E. L. Jacques & C. F. Andrade 1888 ( RBR) .

Taxonomic notes: —In his original publication, de Candolle (1859: 140) described Begonia oxyphylla based on material from Brazil deposited in the Vienna herbarium ( W). Exact information concerning the type locality of the species was not provided, however, as the citation simply stated: “In Brasilia (h. vind.)”.

De Candolle (1861: p. 379) subsequently indicated different type localities in the description of B. oxyphylla in the Flora Brasiliensis, first noting that the collections originated from Rio de Janeiro, but later commenting that the collection locality was uncertain because specimens had been mislabelled. That author finally mentioned the locality as “in umbrosis ad rivos in radice M. Serra d´Itaguahi; Pohl; in Serra de Macacu: Schott” .

In the taxonomic treatment of the Begoniaceae for his Prodromus, de Candolle (1864) provided locality information that coincided, at least in part, with that mentioned in his previous work (de Candolle 1861). The citation differed, however, in that the name Pohl was cited twice, but not as Pohl and Schott but as “Basso di Serra. Pohl. Serra de Mocao, Pohl.”. Smith & Wasshausen (1999) interpreted that to mean that de Candolle (1864) had analyzed two different collections by Pohl deposited in W.

Pohl and Schott visited Brazil in the 19th century as members of the same scientific expedition. In reporting on his expedition to Rio de Janeiro, Pohl stated that the team members left that city in three different directions ( Pohl 1832). Pohl himself went by land towards Angra dos Reis and Ilha Grande; Schott went by land towards Cabo Frio, and another team went by boat to Santa Cruz (Pohl 1851). During those expeditions, Pohl visited Serra de Itaguahi (now Itaguaí) on March 6, arriving at the foot of the Serra de Itaguaí mountains at Fazenda do Ribeiro, four leagues (ca. 6.2 km) from Sepetiba. In the German version of his book, Pohl describes the Portuguese name of the locality as “Basso de Serra Itaguahy” ( Pohl 1832). He also noted that plants were collected at Serra de Itaguaí, but did not name them in detail, citing collections of species of Dorstenia , Cassia , Begonia , Polygala , Piper , as well as ferns ( Pohl 1832).

Analyses of the nomenclatural type of B. oxyphylla deposited at W revealed a collection label with the description “in umbrosis ad rivos Basso di Serras Pohl.—Serra de Mocao, Schott”. The locality “Baixo de Serra” was mentioned in Pohl’s work ( Pohl 1832) and de Candolle (1861) may have noted that “Basso di Serra” (Baixo de Serra, in Italian) is not an exact collection locality as there was no locality referred to as “Serra de Mocao” in Rio de Janeiro. De Candolle may have then attempted to improve on the information provided on the specimen deposited in W that contained two specimens, one of B. oxyphylla and another of B. dentatiloba , as had been reported in previous publications (de Candolle 1861; 1864). The type locality of B. oxyphylla would therefore have been in the lower section of the Serra de Itaguaí mountains, a locality that coincides with the current known distribution of the species. That interpretation leads us to believe that the material provided by Schott belongs to B. dentatiloba and that it was mixed with a collection of B. oxyphylla by Pohl. That interpretation is collaborated by the fact that B. dentatiloba occurs in Serra de Macacu (currently Cachoeiras de Macacu), a locality that Schott probably visited while attempting to visit Cabo Frio (Schott’s team did not arrive at its final destination because one of its members was injured, and they returned to Rio de Janeiro).

As B. oxyphylla is easily distinguished from B. arborescens by its dense to glabrescent indumentum of tomentose-ferruginous with shortly spinous stellate hairs found on the entire plant (especially the younger portions), and especially the veins on the abaxial face of the leaves, rachis of the inflorescence, pedicels, and flowers (vs. puberulous to glabrescent, never ferruginous), leaves oblong, elongated (vs. obovate), with shortly spinous stellate trichomes (vs. trichomes simple), the taxon is re-established as a distinct species.

Figures

FIGURE 1. Begonia oxyphylla A.DC.A, Flowering branch; B, Leaf with detail of indumentum; C, Trichome; D, Male flower; E, Stamen in a dorsal view; F, Stamen in a ventral view; G, Female flower; H, Stigma; I, Capsules (A–C from Jacques 1917 D–I, from Jacques 1919).

FIGURE 2. Begonia oxyphylla A.DC.A, Habit; B, Leaves in adaxial face; C, Leaves in abaxial face; D, Indumentum; E, Indumentum in detail; F, Male flowers and male flower buds; G, Female flowers; H, Capsules (A–C from Jacques 1917; D–E from Schott s.n. (W49658); F–H from Jacques 1919) (A= 10 cm; B= 5.5 cm; C= 5 cm; D= 0.5 cm; E= 0.1 cm; F–G= 2 mm; H= 1.5 mm).