Chamaecrista transversa Afr. Fern.

Bastos, Maria Da Conceição De Carvalho, Marinho, Lucas Cardoso, Fernandes, Rozijane Santos, Zappi, Daniela Cristina, Silva, Tatiane Santana & Rando, Juliana Gastaldello, 2025, Nomenclatural and taxonomic adjustments in Chamaecrista (Leguminosae: Caesalpinioideae) from the Brazilian Cerrado, Phytotaxa 702 (2), pp. 187-196 : 189-191

2. Chamaecrista transversa Afr. Fern. ex. Carv.-Bastos & Rando, sp. nov.

Type:— BRAZIL. Piauí: Bom Jesus do Gurgéia [formally “Bom Jesus”], Serra do Uruçuí, 6 June 1998, A. Fernandes s/n (holotype: EAC n° 26702 image!). Figs 1A–E , 2E–H .

Description:— Branched subshrub ca. 50 cm tall, branches pubescent. Stipules 2–5 × 1–1.5 mm, oval, acuminate apex, cordate base, margin entire, glabrous. Leaves with petiole 3–4 mm, densely pubescent; 2-pairs of leaflets, proximal pair relatively smaller than the distal one, 1.5–3.0 × 1.0–2.0 cm, elliptical to oblong-obovate, rounded apex, base oblique, margin entire, chartaceous to coriaceous, abaxial surface glabrous, adaxial surface slightly pubescent, glaucous in both faces; extrafloral nectary 1, sessile, below the proximal pairs of leaflets. Inflorescence axillary raceme, reduced to single flower; pedicel 10–12 mm long; bracts 2, persistent 1.5–2 × ca. 1.5 mm ovate, membranaceous; bracteoles 2, persistent, 2–3 × 1–1.5 mm, lanceolate to ovate, inserted below the calyx; sepals 5, unequal, 2 external 2–8 mm long, ovate to lanceolate, 3 internal 11–14 × 5–6 mm, lanceolate, abaxial surface glabrous or slightly pubescent, multistriated with parallel veins; petals 5, 4 external, 10–25 × 7–8 mm, ovate, 1 innermost petal cucullate, 15–22 × 1–14 mm obovate; stamens 10, anthers 1–3 mm long; ovary ca. 4 mm long, densely pubescent, style ca. 7 mm long, glabrous. Fruits ca. 5.1 × 9 cm, oblong, pubescent.

Additional specimens examined (Paratypes):— BRAZIL. Goiás: Damianópolis, Estrada para lugarejo Creola , Solo areno-argiloso, relevo plano, 14º30’59”S, 46º14’27”W, 20 February 2003, M. L. Fonseca et al. 4195 ( EAC Image!) ; ibid., M. L. Fonseca et al. 4216 ( EAC image!). Ribeiro Gonçalves, Brejo da Meninas , 04 September 1981, A. Fernandes 10276 ( HUEFS image!) ; Maranhão: Alto Parnaíba, APA Federal, Fazenda Coxilo , 28 August 1996, A. Fernandes s/n ( HUEFS n° 24226 image!) ; Parque Nacional das Nascentes do Rio Parnaíba , PNNRP, 09°50’38”S, 46°16’04”W, 19 de July 2023, M. C. C. Bastos et al. 146 ( CCAA!) ; ibid., M. C. C. Bastos et al. 151 ( CCAA!). Piauí: [Bom Jesus] Estação Ecológica Uruçuí-Una , Boqueirão dos Cavalos, 19 May 1984, A. Fernandes s/n ( EAC n° 12594 image!) ; Serra do Uruçuí , 06 June 1998, A. Fernandes s/n ( EAC n° 26702 image!) ; ibid., Bom Jesus Piauí, Serra do Uruçuí , 15 June 1998, A. Fernandes s/n ( EAC n° 26703 image!) ; Bom Jesus Piauí, Serra do Uruçuí, 15 de June 1998, A. Fernandes & E. Nunes s/n ( EAC n° 26705 image!). Tocantins: Ponte Alta do Tocantins, ESEC Serra Geral de Tocantins, beira de estrada 75 km de Ponte Alta de Tocantins em direção ao Rio da Conceição , 11°05’36”S, 45°07’63”W, 02 February 2021, Schindler et al. 39 ( CEN!). Rio da Conceição , Estação Ecológica da Serra Geral , Estrada para o Rio Verdinho , 07 August 2019, T. S. Silva et al. 101 ( BRBA!, CEN!). São Félix do Tocantins, Jalapão, aproximadamente 9 km de Mateiros, elevação à direita da estrada, 20 September 2012, L. M. Borges et al. 859 ( CEN!, SPF!) .

Nomenclatural notes:— Chamaecrista transversa was invalidly published by Fernandes & Nunes (2005), as the authors indicated two specimens from Piauí state, EAC n° 12594 and EAC n° 26702, as the type collection. Here, we chose to maintain the same name and attribute the species authorship to the original authors to promote nomenclatural stability. We designate the specimen EAC n° 26702 as holotype because it is more complete, bearing flowers and fruits.

Distribution, habitat and phenology:— Chamaecrista transversa is distributed in the states of Maranhão, Piauí and Tocantins, usually in areas of Cerrado. The species was collected with flowers and fruits between April and September.

Taxonomy notes:— Chamaecrista transversa can be recognized by the elliptic to oblong-obovate, coriaceous and glabrous leaflets ( Fig. 2F ) measuring 1.5–3.0 × 1.0–2.0, and the sessile nectary below the first pair of leaflets ( Fig. 1C ) The species also belongs to C. sect. Xerocalyx and its distinction from C. tomentella is explained above (see the previous comment).

Figures

FIGURE 1. A–E. Chamaecrista transversa. A. Branch with leaves. B. Oval stipule. C. Extrafloral nectary in the median portion of the petiole. D. Leaf with two pairs of leaflets. E. Flower in side view. The illustrations were prepared based on specimen M. C. C. Bastos et al. 151. F–K. Chamaecrista tomentella. F. Branch of leaflets. G. Petiole covered in tomentose trichomes. H. Stipule with ciliate margin. I. Nectaries on the petiole. J. Adaxial surface of leaflet. K. Abaxial surface of leaflet. The illustrations were prepared based on specimen M. C. C. Bastos et al. 88. Illustration by R. Santos.

FIGURE 2. A–D. Chamaecrista tomentella. A. Leaf with two pairs of leaflets. B. Leaflet base. C. Senescent flowers. D. Open fruit. E–H. Chamaecrista transversa. E. Branch with leaves. F. Leaflet base and stipule. G. Open flower in front view. H. Flower in side view. Photos A–E by M.C.C. Bastos; G–H by J.G. Rando.