Chamaecrista acosmifolia (Bentham) Irwin & Barneby (1982: 660)

Souza, Alessandro Oliveira De, Cavalcante, Raphael Guarda & Silva, Marcos José Da, 2022, Taxonomic revision of Chamaecrista sect. Absus subsect. Absus (Leguminosae, Caesalpinioideae) with adjustments in the new classification, Phytotaxa 565 (1), pp. 1-82 : 12-16

2. Chamaecrista acosmifolia (Bentham) Irwin & Barneby (1982: 660) ≡ Cassia acosmifolia Bentham (1870: 133) .

Type:— BRAZIL. Minas Gerais: “ Habitat. prope S. João del Rey , prov. Minas Geraes, et in silvis ad Monte Santo prope Bahiam ”, 1818–1819, (fl., fr.), C.F.P. von Martius s.n. (lectotype M217344 ! designated here , isolectotype M217345 !, M217346 !). (Figs. 3 and 4)

= Chamaecrista acosmifolia var. euryloba ( Irwin & Barneby 1978: 247) Irwin & Barneby (1982: 660) ≡ Cassia acosmifolia var. euryloba Irwin & Barneby (1978: 247). Type:— BRAZIL. Minas Gerais: Rio Jequití , 790 m, 25 km E. of Diamantina, 21 March 1970, (fl.), H.S. Irwin, Fonseca, Souza, Reis dos Santos & Ramos 28000 (holotype UB0037165 !, isotypes F0057536 F!, K000555613 !, NY00003697!, NY00003698!, RB00539425!, S-R-8769!, US 00001388!) Syn. nov.

= Chamaecrista acosmifolia var. oropedii ( Irwin & Barneby 1978: 247) Irwin & Barneby (1982: 660) ≡ Cassia acosmifolia var. oropedii Irwin & Barneby (1978: 247). Type :— BRAZIL. Distrito Federal : Rio Contagem, ± 35 km N. of Brasília, 900m, 08 March 1966, H. S. Irwin, R. Souza, J. W. Grear & R. Reis dos Santos 15725 (holotype UB0037166 !, Isotypes K000555615 !, K000555614 !, NY00003699 !, RB, US00001389!) Syn. nov.

= Chamaecrista verruculosa Fernandes & Nunes (2000: 2) . Type:— BRAZIL. Piauí: Bom Jesus, in cerradão 700m, Serra de Uruçuí , 05 June 1998, A. Fernandes s. n. (holotype EAC26715 !, isotype NY452026 !) Syn. nov.

Subshrubs or shrubs, perennial, 0.7–4 m tall, with erect, supporting or pendent branches, in this case with a lianescent appearance. Root nodules unknown. Branches dark brown when mature and green-brown when young, both setuloseviscous and puberulent, including stipules, petiole and rachis; non-exfoliating bark. Stipules 1.5–2.5 × 0.4–0.5 mm long, lanceolate, persistent. Leaves alternate spiral, regularly distributed, plagiotropic; petiole 1–4.5 cm long; rachis 5–20 mm long; leaflets 2 pairs, 1.2–5 × 0.8–2(2.8) cm, distal pair slightly larger, elliptical, largely elliptical or oboval, apex obtuse or emarginate, mucronate or not, base cuneate or oblique, papyraceous, discolored, adaxial side dark green and glabrous and abaxial side dull green and puberulent or glabrescent, margin entire, revolute, sometimes flat, ciliated; secondary veins 4–6 pairs, conspicuous and imprinted on both sides or slightly prominent on the abaxial side. Leafy appendix inter-petioluleabsent. Racemes 4.5–10 cm long, peduncle 8–12 mm, 5–22 flowers, axillary and terminal, erect or slightly pendulous with straight or sometimes flexuous axis, congested, setulose-viscous and villosule, including pedicel, external surface of the bracts, bracteoles and sepals. Bracts 2 × 1 mm, lanceolate, persistent. Bracteoles 0.3–0.7 × 0.5 mm, lanceolate, persistent. Buds 5–6 × 4–5 mm, ovoid or globoid, apex obtuse or apiculate, green or yellow with vinaceous macules. Flowers 2–2.5 × 1–1.5 cm; pedicel 1–2 cm long, straight, ascending, even when fruited; sepals 0.9–1.3 × 3.5–4.5 mm, elliptical or lanceolate, apex obtuse or acute, externally yellowish-green; 4 flat suborbicular or largely oboval petals and 1 inner falcate-curled petal encircling part of the stamens, 1.1–1.3 × 0.8–1 cm, yellow; stamens 10, 3–5.5 mm long, anthers not barbulate; ovary 3–4 × 1.5–2 mm,setulouse-viscous and puberulent; style 1–1.2 cm long, curved in upper third, glabrous.Legumes 2–2.5 × 0.6–0.7 cm, linear-oblong, setuloseviscous and sparsely puberulent, dark brown. Seeds 4–6, 4–6.5 × 5–5.5 mm, oblong or obovoid, blackish.

Etymology: —Epithet “ acosmifolia ” in allusion to leaves similar to those of species of the genus Acosmium .

Geographical distribution and habitat:— Chamaecrista acosmifolia is a Brazilian species occurring in the CenterWest (Goiás, Distrito Federal), Northeast (Bahia, Maranhão, Piauí, Sergipe) and Southeast (Minas Gerais) regions (Fig. 37B), with its distribution being extended here to the state of Sergipe and excluded for the states of Mato Grosso and Tocantins, since the only two specimens found in these two states are actually a misidentification (= Ch. viscosa , specimen from Mato Grosso) and a specimen cultivated in experimental field at EMPRAPA (example from Tocantins - J. Menezes & F. Souza 96 (CEN)). The species is more frequent in areas known as Serras Gerais on the borders of the states of Goiás, Bahia to the south of Piauí and Maranhão, where it grows associated with the edges of gallery forests, typical cerrado, cerradões or their transition to Caatinga, between 500 and 1000 meters above sea level on sandy or sandy-clay soils.

Flowering and fruiting:—It flowers from March to August and bears fruit from April to August, with the most intense flowering from March to May.

Conservation status:—The species has an estimated Range of Occurrence around 500,000 km 2, which according to the criteria established by the IUCN (criteria B, C, D) allows us to consider its conservation as Least Concern (LC). However, the main region of occurrence of the species suffers intense loss of vegetation cover due to the advance of agribusiness, mainly in the west of Bahia state where individuals were occasionally found in fragments of Legal Reserve of agricultural properties. This will certainly cause the species to decline in the coming decades.

History, taxonomic adjustments and typification:— Cassia acosmifolia was described by Bentham (1870) in Flora Brasiliensis based on the collection of Martius without a doubtful location number between Minas Gerais and Bahia “Habitat prope S. João del Rey, province Minas Geraes, et in silvis ad Monte Santo prope Bahiam: Martius”. The type material mentioned by Bentham (l.c.) is deposited in the Herbarium of Munich / Martii (M) with three copies, one of which has the label “prope S. João del Rey, prov. Minas Geraes” and dated 1818 and the other two “ et in silvis ad Monte Santo prope Bahiam ” dated 1819.

In 1978, when reviewing the genus Cassia, Irwin & Barneby , in order to determine the real type locality of the species, analyzed the type specimens and compared them with the history of Martius collections in Brazil. The authors reported that the type locality of C. acosmifolia is probably Monte Santo in Bahia, as Martius would have visited Brazil in the same region in 1819. Thus, the duplicate with “ prope S. João del Rey, prov. Minas Geraes ” from 1818 would have been an error in the labeling of the material. However, Irwin & Barneby (l.c.) at the time treated the 3 duplicates with a single exsiccate, which would have been assembled in three parts. However, analyzing the type material, we see that they were assembled in separate ways to correspond to duplicates, in such a way that the three copies have different barcodes. Thus, even if this is the same collection and is deposited in the same herbarium, it is necessary to choose a lectotype. Therefore, we are proposing here as a lectotype of the species the specimen of Barcode M217344, and the others (M217345 and M217346) their isolectotypes.

Still in the work of 1978, Irwin & Barneby established for the species the varieties C. acosmifolia var. euryloba and C. acosmifolia var. oropedii based on specimens from the Federal District / Goiás and Minas Gerais, respectively, and differentiated them by the length of fertile branches, density of inflorescences and flowers and indumentum of branches, buds and fruits. Four years later, the same authors, when reestablishing the genus Chamaecrista , combined C. acosmifolia in Chamaecrista (= Ch. acosmifolia ). Cassia acosmifolia var. euryloba was described by Irwin & Barneby (1978) as an intermediate of the variety acosmifolia and oropedii and reported as endemic to Minas Gerais. However, no other specimen besides the type has been found for such a variety since its description. In Minas Gerais only specimens that fit the typical variety have been collected, which led us to conclude that the material used by Irwin & Barneby (l.c.) to describe Ch. acosmifolia var. euryloba corresponds to an extreme of variation. Chamaecrista acosmifolia var oropedii was distinguished from the others by its more elongated inflorescences with more widely spaced flowers and has been found in Goiás and the Federal District with inflorescences as congested as those of the typical variety, which led us to infer that the spacing of the flowers is related to the inflorescence maturation stage, as also observed in populations of Ch. acosmifolia var. acosmifolia from Bahia and Piauí. Thus, with the analysis of several specimens of Ch. acosmifolia from different locations where the species occurs, we can conclude that the subtle differences pointed out by Irwin & Barneby (l.c.), for the recognition of varieties, are not consistent, overlap in many cases and are difficult to define. In view of this, we are not admitting any infraspecific category for Ch. acosmifolia .

Fernandes & Nunes (2000) described Chamaecrista verruculosa based on their own collections from Serra de Uruçuí, in Piauí, and allocated it to Ch. sect. Absus ser. Glutinosae (H.S. Irwin & Barneby) H.S. Irwin & Barneby , claiming that it had glands on the margins of the leaflets like other members of this series. Analyzing the type collection of the species and collections from the same type location, it was found that Ch. verruculosa is actually Ch. acosmifolia . All features between the two taxa are completely overlapping (e.g. shape, consistency and coloration of leaflets, position, organization of inflorescences, and shape and size of floral pieces). The glands at the margins of the leaflets reported by Fernandes (l.c.) are actually glandular trichomes with an enlarged base, which are characteristic of the setulous indumentum commonly found among all species in the Absus section; and has no relation to the glutinous punctuations of the leaflets that are found in the leaves of species of the series Glutinosae (sensu Irwin & Barneby) . Therefore, we also propose Ch. verruculosa as a synonym of Ch. acosmifolia .

Characterization and morphological relationships: — Chamaecrista acosmifolia is commonly an erect shrub with hanging branches, supporting and lianescent or not, but it can appear as a sub-shrub when growing in more open areas of the cerrado or its transition to caatinga. Its leaves have discolored elliptical leaflets with revolute margins, generally puberulent on the abaxial surface at least along the main vein.

Among the other congeners studied Ch. viscosa and Ch. major are the most similar to Ch. acosmifolia by the leaves always with two pairs of leaflets and branches with several axillary racemes at their ends. However, Ch. acosmifolia is distinguished from the latter by supporting or hanging branches; discolored leaflets with dark green adaxial face and dull green abaxial face; flowers with four suborbicular or largely oboval flat petals (vs. erect branches, concolorous leaflets; the 4 flat petals oboval, oblong-oboval or oboval-elliptic in Ch. major and Ch. viscosa ).

Specimens examined:— BRAZIL. Bahia: Barreiras, 8km NW. of Barreiras, incomplete road to Santa Rita da Cassia , 600m, 03 March 1971, est., H. S . Irwin et al. 31450 ( UB); ib., Espigão Mestre near Barreiras airport, ca. 5 km NW of Barreiras, 650 m, 04 March 1971, (fl.), H. S . Irwin et al. 31458 ( NY, UB). Caetité, Região de Brajinho das Ametistas, área da Bahia Mineração , 14°19’24”S, 42°33’25”W, 980m, August 2018, (fl.), M. S . Mendes et al. 407 ( BHCB); Catolândia, BR-242, ca. 30 km antes de Barreiras , 12°08’23.4”S, 44°45’33”W, 733m, 14 May 2017, (fl., fr.), A. O . Souza et al. 2091 ( UB); Ibotirama, Rodovia Br-242 (Ibotirama-Barreiras) km 85, 12°07’00’’S, 44°02’00’’W, 07 July 1983, (fr.), L . Coradin et al. 6624 ( CEN); Muquém do São Francisco, BR-242 a partir do trevo para Brejolândia em direção a Barreiras , 12°13’34.3”S, 43°53’23.2”W, 853m, 14 May 2017, (fl., fr.), A. O . Souza et al. 2089, 2090 ( UB, UFG); Riachão das Neves, estrada para o aterro Sanitário, 13°45’49’’S, 44°54’39’’W, 600m, 06 April 2005, (fl.), J. G . Carvalho-Sobrinho et al. 423 ( HUEFS); São Desidério, Estrada para a Fazenda Grande Oeste e Faz. Riacho Doce , ca. 15 km da entrada da BR-463, 12°28’43.4”S, 45°08’54.2”W, 731m, 14 May 2017, (fl., fr.), A. O . Souza et al. 2098 ( UB, UFG). Distrito Federal: Taguatinga, QNL Taguatinga Norte , 30 March 1980, (fl.), F. C . Silva 298 ( IBGE, NY) . Goiás: Cocalzinho, Fazenda Bombaça , 15°44’47”S, 48°45’13”W, 1115m, 23 March 2002, (fl.), M. L . Fonseca et al. 3292 ( IBGE, NY); Colinas do Sul, margem esquerda do Rio Preto , 13°41’28”S, 48°04’22”W, 330m, 17 April 2002, (fl.), G . Pereira-Silva et al. 6409 ( CEN, UFG); Formosa , Rio Paraná, ca. 35km N of Formosa , 950m, 30 March 1966, (fl.), H. S . Irwin et al. 14257 ( UB); ib., Rio Tiquiri- Formosa , 25 May 1967, (fl.), E. P . Heringer 11519 ( NY); Pirineus, Parque Estadual dos Pirineus, entrada por Cocalzinho , 15°28’30”S, 48°29’37”W, 1313m, 17 March 2014, (fl.), J. E. Q . Faria 3953 ( UM); São João da Aliança , Serra Geral do Paraná, ca. 3 km sul de São João D’Aliança, 14 March 1971, (fl.), H. S . Irwin et al. 31723 ( NY, UB); ib., 3 km by road S . of São João da Aliança , 1040m, 21 March 1973, (fl.), W. R . Anderson 7637 ( NY); ib., 23 March 1973, (fl.), W. R . Anderson et al. 7776 ( NY, UB) . Maranhão: Loreto, caminho para a Fazenda Trabalhosa , 21 April 1980, (fl., fr.), A . Fernandes & E . Nunes s. n. ( EAC0008484 ); São João dos Patos, estrada para Barão de Grajaú , BR230 , 19 April 1980, (fl.), A . Fernandes & E . Nunes s. n. ( EAC0005436 ) . Minas gerais: Januária, distrito de Fabião, 2 km na estrada partindo do abrigo do Malhador , 15°07’85”S, 44°15’17”W, 23 May 1997, (fl.), J. A . Lombardi & A . Salho 1631 ( BHCB, NY, SP); ib., Vale do Rio Peruaçu , 15°07’19”S, 44°15’27.8”W, 20 March 2003, (fl.), L. V . Costa & J. C . Amado 140 ( BHCB) . Piauí: Bom Jesus, entre Bom Jesus e Estação Ecológica de Uruiçuí-Una , 13 April 1981, (fl.), M. R . Del’Arco 1630 ( UEC); ib., 18 May 1997, (fl., fr.), L. P . Félix 7754 ( HUEFS); Caracol, Serra das Confusões, 06 May 1980, fl. (fr.), A . Fernandes & P . Bezerra s. n.( EAC8701 ); ib.,, subida da Serra das Confusões , 05 May 1981, (fl., fr.), A. J . Castro & M. R . Del’Arco 1115 ( UEC); Curimatá, APA de Curimatá , 10 June 1999, (fl., fr.), A . Fernandes s. n. ( EAC 28310); Currais, Rodovia PI-392, de Bom Jesus em direção a ESEC Uruçui-Una ca. 5 km antes da rodovia Transcerrado , 08°49’14.6”S, 44°36’15.6”W, 569m, 21 July 2017, (fr.), A. O . Souza & L. L. C . Antunes 2165 ( UB); Eliseu Martins, 17 April 2005, (fl.), L. W . Lima-Verde et al. 3256 ( EAC); Ribeiro Gonçalves, Estação Ecológica de Uruçui-Una , 14 April 1981, (fl.), A . Fernandes & Del’Arco ( EAC9984 ); São Raimundo Nonato, Carnaiba , 07 April 1979, (fl., fr.), A . Fernandes s. n. ( EAC6109 ); Uruçuí, entre Uruçuí e Bertolina , 08 July 1980, (fl.), A . Fernandes & E . Nunes s. n. ( EAC8776 ) . Sergipe: Gararu , 9°59’24.0”S, 36°59’24.0”W, 26 August 2014, (fl., fr.), F. B . Gonçalves 347 ( ASE) . Tocantins: Arraias , cultivada em campo experimental do CPAC da EMBRAPA, 06 July 1975, (fl.), J . Menezes & F . Souza 96 ( CEN) .