Bauhinia arleneae A.C.B. Santos & L.P. Queiroz, 2022

Dos Santos, Antonio C. B., De Queiroz, Luciano P., Paula, Antonio P. O. & Carvalho, Reginaldo De, 2022, A new species of Bauhinia ser. Cansenia (Cercidoideae, Leguminosae) endemic to the Atlantic Forest in the state of Bahia, Brazil, Phytotaxa 568 (2), pp. 213-220 : 214-218

Bauhinia arleneae A.C.B. Santos & L.P. Queiroz , sp. nov.

Type: — BRAZIL. Bahia: Uruçuca, Serra Grande , Parque Estadual da Serra do Conduru , 14º25’23”S 39º03’37”W, 21 May 2021 [fl., fr.], A.C.B. Santos & L. Daneu 59 (holotype HUEFS!, isotypes NY!, RB!, PEUFR!, HCDAL!). Figures 1 , 2 .

Diagnosis: —The eastern Brazilian Bauhinia arleneae is similar to the Amazonian Bauhinia cinnamomea Candolle (1825: 517) with both species sharing unifoliolate entire elliptical leaves with acuminate apex, and flowers paired along the pseudoracemes, but differing by the multi-stemmed shrubby or treelet habit (vs. erect treelet in B. cinammomea ), leaves with 3 (rarely 5) primary veins and lacking a marginal vein (vs. 7 primary veins plus a marginal vein), glabrous in both faces (vs. the lower face puberulous and with sparse glandular hairs), and cuneate to obtuse base (vs. rounded to truncate base), fruits up to 2 cm wide with coriaceous-woody, reticulate, light brown valves (vs. valves 2.2 cm or wider, thick, woody and rugous, almost black).

Description:—Multi-stemmed shrubs or treelets 3–5 (6) m tall, with long and flexuous stems, DBH up to 3.7 cm, unbranched at the base, bark grayish; distal internodes (1.5) 2–4 cm long. Extrafloral nectaries 1–2 mm long, conical, yellowish, close to the base of the petiole, present only in a few leaves. Stipules ca. 1 mm long, ovate, glabrous, membranaceous and caducous, present only in the distal leaves. Leaf unifoliate; petiole 0.8–2.2 (3.0) cm long, thin, glabrous and canaliculate on the upper surface; pulvinus 3–5 mm long; pulvinulum (3) 4–5 (6) mm long; leaf blade entire, 14–22.5 (27.5) × (4.5) 6.5–9.0 cm, chartaceous to papyraceous, elliptical to narrowly elliptical, base obtuse to cuneate, apex acuminate to slightly cuspidate, primary veins 3 (rarely 5), the upper surface glabrous with inconspicuous primary, secondary and tertiary veins, lower surface glabrous with prominent primary, slightly prominent secondary and reticulate tertiary veins. Inflorescence a terminal pseudoraceme, 3–7 cm long, short-pedunculate; peduncle 1.5–2.0 cm long; flowers in pairs along the rachis; bracts 1–2 × 1–2 mm in one pair, alternately arranged at the base of the pedicel; pedicel 0.7–1.3 mm long. Floral buds 2.8–4.2 cm long, linear, 5-angled, minutely tomentose with short adpressed and ferruginous trichomes. Flowers andromonoecious, 50–58 mm long; hypanthium 11–16 mm long, cylindrical-tubular, internally slightly puberulous, externally minutely ferruginous tomentose; sepals 5, (3.5) 5.3–5.5 × (0.1) 0.2– 0.4 cm, fleshy, minutely ferruginous tomentose on the outer surface, glabrous on the inner surface, becoming curled when the flower is open; petals 5, 23–35 × 2.0– 3.2 mm, single-nerved, white, linear and glabrous; stamens 10 (present in male and hermaphrodite flowers), filaments 35–50 mm long, joined at the base in a short staminal column 2–4 mm long, minutely whitish tomentose on the inner surface, anthers ca. 9 × 1.5 mm long, dorsifixed close to the base, dehiscing by introrse and longitudinal slits; gynoecium (only present in hermaphrodite flowers) ca. 32.5 mm long, stipe ca. 15 mm long, ovary ca. 6 × 1 mm, puberulous with yellowish hairs, 8–10-ovulate, style ca. 10 mm long, glabrous, stigma ca. 1.5 mm long, glabrous and with an oblique surface. Legume elastically dehiscent, 13.5–15 (22) × 1.5–2.0 cm, linear, apex acute and base cuneate, stipe 2–3 cm long; valves coriaceous-woody, reticulate and light brown. Seeds ca. 11 × 8 mm, suborbiculate, compressed, testa black, smooth, and bony.

Distribution and habitat: — Bauhinia arleneae is known only from the central-eastern region of the state of Bahia, in tropical humid forests ( Figure 3 ). Apart from one collection from Salvador, most of the collections are from the Southern Bahian Atlantic Forest, a species-rich area where several legume taxa have been described in the last 50 years, such as the endemic genus Harleyodendron Cowan (1979: 72) and the species Brodriguesia santosii Cowan (1981: 9) , Chamaecrista amorimii Barneby (1999: 331) , Inga unica Barneby & Grimes (1994: 66) , Moldenhawera congestiflora Vivas & Queiroz (2019: 285) , Parkia bahiae Hopkins (1982: 347) and Zollernia magnifica Carvalho & Barneby (1993: 210) .

Phenology: —Flower buds and flowers were collected from January to September and fruits from February to November.

Conservation status: —The new species is assessed as endangered (EN) according to IUCN (2012) criteria B1ab(i, ii, iii)+2ab(i, ii, iii) as it presents AOO = 24 km ² and EOO = 4310.29 km ² and occurs in severely fragmented areas subject to continuous deforestation.

Etymology: —The epithet “arleneae” is a tribute to Dr. Maria Arlene Pessoa da Silva, professor at the Department of Biological Sciences at Universidade Regional do Cariri – URCA, Crato, Ceará, Brazil, for her contribution to botanical studies in Northeastern Brazil, as well as for her dedication to the academic and professional training of several undergraduate and graduate students.

Vernacular name: —Pé-de-cabra (L.A. Mattos-Silva et al. 505)

Taxonomic notes

Among the species of Bauhinia ser. Cansenia , B. arleneae is similar to B. cinnamomea due to both being treelets occurring in the understory of humid forests, and having entire leaves with acute apex, linear-lanceolate long-clawed petals as long as the filaments and the staminal column with sparse indument on the inner side ( Vaz & Tozzi 2003b). However, B. cinnamomea usually has leaves with 7 (rarely 5) primary veins, a prominent marginal vein on the underside, and straight, craspedodromous external secondary veins reaching the marginal vein, while B. arleneae has leaves with 3 (rarely 5) primary veins, without a marginal vein and with camptodromous external secondary veins. Bauhinia arleneae is restricted to ombrophilous forests on the south-central coast of Bahia, in northeastern Brazil, while B. cinnamomea occurs in the central and western Amazon Forest ( Vaz & Tozzi 2003b).

Among species of Bauhinia ser. Cansenia recorded for the Atlantic Forest of Bahia, B. arleneae shares with B. corifolia Queiroz (2020: 294) the entire leaves with glabrous adaxial surface and flowers in pairs along the pseudoraceme, but B. arleneae has plane leaflets, 14–22.5 (27.5) cm long, chartaceous to papyraceous, elliptical to narrowly elliptical, with obtuse to cuneate base, acuminate to slightly cuspidate apex, primary veins 3 (rarely 5), while B. corifolia has leaflets 7–10.5 cm long, rigid coriaceous, with cordate to rounded base, retuse to rarely truncate or emarginate apex and revolute margin, with 7–9 primary veins ( Queiroz et al. 2020).

Field characters of Bauhinia arleneae include the concolorous leaves with a bright yellowish green adaxial surface and slightly paler yellowish green abaxial surface. The immature fruits are bright olive green in color. The conical and yellowish extrafloral nectaries, close to the base of the petiole, can be confused with spinescent structures due to their rigid texture with an almost pungent apex.

The analyzed specimens present two types of flowers in the same individual: male only and hermaphroditic, characterizing the species as andromonoecious. In Bauhinia ser. Cansenia , this variation of floral type was previously recorded only for B. cupulata Bentham (1870: 188) ( Vaz & Tozzi 2003b).

Additional Specimens Examined: — BRAZIL. Bahia: Camamú, Rodovia BA-650, Camamú / Travessão , entrada a 15,7 Km da sede municipal, fazenda Zumbi dos Palmares (assentamento) ca. 1 Km da rodovia e ca. 6,3 Km na viscinal para a fazenda Dandara , 14º00’54”S 39º08’20”W, 22 February 2000 [fl., fr.], J.G. Jardim et al. 2741 (CEPEC!, NY!, UESC!, HUEFS!) ; Camamú, Rodovia Travessão (BR-101) a Camamu, Km 26, em frente a entrada das Fazendas Agrobrahma e Alfa, 19 September 1988 [fr.], L.A. Mattos-Silva et al. 2532 (CEPEC!, MBM) ; Camamú, Rodovia Travessão/Camamu, Km 33. Ramal a direita para Fazenda Brahma, 14º00’S 39º13’W, 15 June1979 [fr.], L.A. MattosSilva et al. 505 (CEPEC!, US) ; Igrapiúna, Rodovia para Itubera (BR 001), Reserva de Michelin , 13º49’S 39º11’W, 01 August 2008 [fr.], Assoc. Myrtaceae Class 21 (HUEFS!, ASU) ; Igrapiúna, Reserva Espinita, Litoral Sul, 13º52’30”S 39º09’10”W, 01 June 2019 [fr.], M.L. Guedes et al. 31721 (ALCB!) ; Igrapiúna, Litoral Sul, Mata do pacangê, Ituberá/ Igrapiúna, 10 April 2006 [fr.], R.M. Valadão & M.L. Guedes 427 (ALCB!) ; Igrapiúna, Litoral Sul, Mata da Vila-V, Ituberá/Igrapiúna, 25 June 2006 [fr.], R.M. Valadão & M.L. Guedes 428 (ALCB!) ; Itacaré , Fazenda Capitão a 7,9km W do entroncamento BA 001 na estrada de Itacaré a Ubaitaba, Sul da Bahia , 14º20’S 39º05’W, 04 November 2001 [fr.], W.W. Thomas et al. 12770 (CEPEC!) ; Itacaré , Rodovia Ilhéus-Itacaré, km 59, Fazenda Boa paz, 14º20’08”S 39º01’55”W, 13 September 2006 [fr.], J.R.V. Iganci et al. 192 (CEPEC!) ; Itacaré , 1Km ao N e 2,5Km a W da junção com Marambaia, BR-101 para Itacaré (BA-654), 6Km a W de Itacaré, 14º20’S 39º05’W, 16 May 1992 [fl., fr.], W.W. Thomas et al. 9394 (CEPEC!, NY!) ; Itacaré , Loteamento da Marambaia , 6Km ao SW de Itacaré, BR-101, 16 February 1993 [fl.], A.M. Carvalho et al. 4126 (CEPEC!) ; Salvador, Região Metropolitana de Salvador , Mata dos Oitis , 26 September 1976 [fl.], J. Araújo et al. 81 (ALCB!) ; Ubaitaba, ramal a esquerda na estrada Ubaitaba/ Itacaré , a 4 Km do Loteamento da Marambaia , 20 November 1991 [fr.], A.M. Amorim et al. 443 (CEPEC!, NY!) ; Uruçuca, Rodovia Ilhéus/ Itacaré , entrada a esquerda, na rotatória de acesso a Uruçuca, ca. 9,5Km, ramal a esquerda do Parque Estadual Serra do Condurú , 14º29’S 39º06’W, 23 October 2003 [fr.], P. Fiaschi et al. 1727 (CEPEC!, NY!) ; Uruçuca, Fazenda Lagoa 7,7 Km na estrada que liga Serra Grande / Itacaré , Distrito de Serra Grande , 06 May 1996 [fr.], A.M.S. da F. Vaz et al. 1037 (CEPEC!) ; Uruçuca, Parque Estadual da Serra do Condurú , 14º25’S 39º05’W, 10 May 2009 [fr.], D. Piotto 1998 (CEPEC!) ; Uruçuca, 7,3Km na estrada Serra Grande/ Itacaré , Fazenda Lagoa do Conjunto , Fazenda Santa Cruz, Distrito Serra Grande, 14º25’S 39º01’W, 28 February 1994 [fl., fr.], A.M. Carvalho et al. 4407 (CEPEC!, NY!, US) ; Uruçuca, 4,6 Km de Serra Grande em direção a Itacaré , 14º25’50”S 39º03’13”W, 24 January 2004 [fl.], T.S. Nunes et al. 1009 (HUEFS!, HCDAL!) ; Uruçuca, ca. 5 Km de Serra Grande , 14º26’23”S 39º03’17”W, 01 October 2008, L.P. Queiroz 13842 (HUEFS!) ; Uruçuca, Serra Grande, 14º35’S 39º17’W, 29 June 2017 [fr.], M.L. Guedes et al. 25801 (ALCB!) ; Uruçuca, Distrito Serra Grande, Parque Estadual da Serra do Conduru , 14º25’23”S 39º03’37”W, 21 May 2021 [fl., fr.], A.C.B. Santos & L. Daneu 59 (HUEFS!, NY!, RB!, HCDAL!, PEUFR!) .

Figures

FIGURE 1. Bauhinia arleneae—A: flowering branch; B: detail of the branch at the petiole attachment showing extrafloral nectaries; C–E: upper (C) and lower (D) leaf surface and a detail of the lower surface (E); F: flower in frontal view; G: detail of the petal; H: stipitate gynoecium; I: detail of the staminal column minutely whitish tomentose on the inner surface; J: stamen; K: anther; L: immature fruit and M: seeds. Drawing by R. Carvalho based on the holotype.

FIGURE 2. Bauhinia arleneae–A: General aspects of the branch showing leaf disposition; B: Immature fruit; C: floral buds and D: flower. Holotype field photos: A.C.B. Santos

FIGURE 3. Map of Northeastern Brazil showing the state of Bahia (BA) and the distribution of Bauhinia arleneae (red circles).