Chamaecrista oligosperma (Bentham) Irwin & Barneby (1982: 648)

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 : 67

16. Chamaecrista oligosperma (Bentham) Irwin & Barneby (1982: 648) ≡ Cassia oligosperma Bentham (1870: 147) . Type:— BRAZIL. Minas Gerais: “ in campis aridis prope Contendas ”, August 1818, (fl., fr.), Martius s. n. (holotype M0217518!). (Figs. 31 and 32)

Subshrubs perennial, diffusely branched and decumbent. Root nodules absent. Branches light brown, setose-viscous and puberulent indumentum including stipules, petiole and rachis; non-exfoliating bark. Stipules 1–2.2 × 0.4–0.5 mm, linear, persistent.Leaves alternate-spiral, regularly distributed along the stem, ascending or plagiotropic; petiole 0.2–2.2 cm long; rachis 2–6 cm long; leaflets (6)7–18 pairs of similar size, 2.5–20 × 1.2–5 mm, elliptical, ovalelliptical, oboval, oblong or oblong-elliptic, apex obtuse, emarginate or acute, base rounded, obtuse or slightly oblique, papyraceous, concolorous, pale green, sparsely setulose-viscous and puberulent, on both sides, or glabrescent; margin entire, flat, ciliated or not; secondary veins 2–3 pairs, inconspicuous and imprinted on both sides. Leafy appendix inter-petioluleabsent. Racemes 2.5–6 cm long, peduncle 0.5–1 cm long, 3–15 flowers, lax, terminal and axillary, erect or slightly pendulous with straight axis, flexuous or sinuous, setulose-viscous and villous, including pedicel, bracts, bracteoles and external face of the sepals. Bracts 1–32.5× 0.4–1 mm lanceolate, persistent. Bracts 1–1.5 × 0.5–1 mm, similar to bracts. Buds 3–6 × 3–4 mm, ovoid or globoid, apex obtuse or apiculate.Flowers 1.5–2.1 × 0.7–1.5 cm; pedicel 1–1.8 cm long, straight and ascending, sinuous, recurved or not when fruited; sepals 5–7 × 2–4 mm, elliptical, apex obtuse, reddish or yellowish with vinaceous macules externally; 4 flat, oboval petals and 1 falcate-curled inner petal, 9.5–11 × 4–6.5 mm, orange or yellow; stamens 10, 4–5 mm long, anthers not barbulate; ovary 4.5–5 × 1.5 mm, villosule and setulose; style 1–1.1 mm long, curved in upper third, glabrous. Legumes 2–3.2 × 0.7–1.2 cm, oblong, not very puberulent and setulose-viscous, dark brown. Seeds 1 or 2, rarely 3, 5–5.5 × 5–5.5 mm, oblong or obovoid, blackish

Etymology: —in reference to fruits with few seeds.

Geographical distribution and habitat:— Chamaecrista oligosperma according to Flora e Funga do Brasil (2022), it is distributed along the borders between Bahia, Goiás, Minas Gerais and Tocantins, and is being first recorded here for the states of Maranhão and Piauí (Fig. 39 C). Chamaecrista oligosperma is common in the regions known as “Serra Gerais”, mainly in the borders of the states of Goiás, Tocantinas and Bahia. It lives in typical cerrado or in the transition from these to campo sujo, in the midst of grasses on clayey or sandy soils between 400 and 950 m altitude .

Flowering and fruiting:—collected with flowers and fruits from March to September, but especially in July.

Conservation status: —Species with conservation interpreted as Least Concern (LC) given its Extension of Occurrence estimated at more than 50 thousand km 2 and the increase in areas protected by law.

Taxonomic history:— Cassia oligosperma was described by Bentham (1870) based on a collection by Martius s. n., from the state of Minas Gerais, and positioned in C. sect. Absus ser. Microphyllae ( Bentham 1870: 146) Irwin & Barneby (1982: 651) by leaves with many minute leaflets. Irwin & Barneby (1978) transferred it to C. sect. Absus subsect. Absus ser. Oligospermae arguing that it differed from the others in the series Microphyllae (sensu Bentham l.c.) by its axillary inflorescences and orange flowers. Four years later Irwin & Barneby (1982) transferred C. olisgosperma to the genus Chamaecrista (= Ch. oligosperma ) and placed it in Ch. sect. Absussubsect. Absus ser. Oligospermae . In view of the results of the phylogenetic studies by Souza et al. (2021), Ch. oligosperma was allocated in Ch. sect. Absus subsect Absus in the recent classification.

Characterization and morphological relationships: —In the Ch. sect. Absus subsect Absus , where the species has leaves with two pairs of leaflets, Ch. oligosperma escapes the rule for leaves with (6)7–18 pairs of leaflets, which makes it easily identified. In addition, it is a decumbent subshrub with setulose-viscous branches; axillary and congested inflorescences; yellow or orange petals and legumes with 1 or 2(3) seeds.

Due to its multifoliate leaves, Ch. oligosperma can be confused with other species in the section Absus , such as Ch. cavalcantina ( Irwin & Barneby 1978: 35) Irwin & Barneby (1982: 648) and Ch. neesiana ( Bentham 1870: 148) Irwin & Barneby (1982: 653) . However, these last taxa are positioned in Ch. sect. Absus subsect Viscosa according to Souza et al. (2021).

Specimens examined:— BRAZIL. Bahia: Barreiras, Estrada para Luís Eduardo Magalhães , cerca de 28 km de Barreiras , 12°17’00”S, 45°12’00”W, 650m, 16 April 2004, (fl.), V. C . Souza et al. 29916 ( ESA); Coribe, Rodovia São Félix do Coribe , 13°49’00”S, 44°27’00”W, 610m, 02 September 1994, (fr.), G . Pereira-Silva 2526 ( CEN); Correntina , Chapadão ocidental da Bahia, ca 15km SW of Correntina on the road to Goiás, 13°29’00”S, 44°43’00”W, 600m, 25 April 1980, (fl.), R. M . Harley 21733 ( NY); Jaborandi, ca. 58 km L de Posse , 14°08’50”S, 45°50’07”W, 870m, 18 May 2001, (fl.), F . França et al. 3709 ( IBGE); Jaborandi, Fazenda Trijunção (Guará), cerrado a 500 m antes da entrada da fazenda, 14°37’6.7”S, 45°49’52.8”W, 861m, 05 March 2015, (fl., fr.), A. O . Souza et al. 1703, 1704, 1705, 1706, 1707 ( UB, UFG); ib., Fazenda Trijunção (Guará), entrada da Fazenda ca. 1 km após a plantação de eucalipto em borda de cerrado, 14°37’42.7”S, 45°48’46.9”W, 871m, 05 March 2015, (fl., fr.), A. O . Souza et al. 1715 ( UB, UFG) . Goiás: Posse, Serra Geral de Goiás, Rio da Prata , ca. 6 km S . of Posse , 800m, 06 April 1966, (fl., fr.), H. S . Irwin 14444 ( NY); ib., 07 April 1966, (fl., fr.), H. S . Irwin 14489 ( NY); ib., ca. 35 km N. E . of Posse , 950m, 16 April 1966, (fl., fr.), H. S . Irwin 14938 ( NY); ib., BR-020 entroncamento Posse – Mimoso do Oeste , 14°05’00”S, 46°17’00”W, 900m, 08 July 1993, (fl., fr.), G . Pereira-Silva 1326 ( CEN); ib., ca. 5 km a leste da cidade de Posse, 14°10’00”S, 46°10’00”W, 27 April 1996, (fl.), B. A. S . Pereira & D. Alvarenga 2982 ( EAC); ib., Na entrada da cidade de Posse, cerrado próximo aos loteamento no começo da cidade, 14°06’16.1”S, 46°19’54.4”W, 854m, 11 July 2014, (fl., fr.), A. O . Souza et al. 1210, 1211, 1212 ( UB, UFG) ; Maranhão: Alto Paranaíba , APA Federal, Fazenda Cotilha , 20 August 1996, (fl., fr.), A . Fernades et al. s. n. ( EAC 24228) ; Minas Gerais: Arinos , 18 May 1994, (fl.), M . Brandão 23630 ( PAMG); Formoso, fazenda Trijunção (Guará), na área do Parque Nacional Grande Sertão Veredas, próximo a divisa com a Fazenda Trijunção em direção ao Marco dos três estados, 14°52’38.1”S, 46°02’10.1”W, 942m, 05 March 2015, (fl., fr.), A. O . Souza et al. 1726 ( UB, UFG) . Piauí: Barreira do Piauí, 15 July 1981, (fl., fr.), A . Fernandes et al. s. n. ( EAC 10584); ib., 18 July 1981, (fl., fr.), A . Fernandes et al. s. n. ( EAC 10600); Ribeiro Gonçalves, Brejo das Meninas , 04 September 1981, (fr.), A . Fernandes & V . Rodrigues s. n. ( EAC 10742) . Tocantins: Dianópolis , 11°36’37”S, 46°28’09”W, 722m, 25 September 2003, (fr.), A. O . Scariot et al 746 ( CEN); ib., estrada de Dianópolis para Mateiros, 11°35’5.6”S, 46°35’29.4”W, 689m, 18 July 2017, (fl., fr.), A. O . Souza & L. L. C . Antunes 2135 ( UB, UFG); ib., estrada de Dianópolis para Mateiros próximo da divisa com a Bahia, 11°29’45.9”S, 46°32’51”W, 843m, 18 July 2017, (fl., fr.), A. O . Souza & L. L. C . Antunes 2141 ( UB); Mateiros, Rio Novo , norte, estrada das dunas, 10°35’00”S, 46°39’00”W, 09 May 2001, (fl.), L. H. S . Silva 934 ( CEN); ib., Parque Estadual do Jalapão, estrada para Boa Esperança, brejo do Guará , 10°19’55”S, 46°37’31”W, 420m, 18 June 2002, (fl., fr.), T. B . Cavalcanti 2929 ( CEN); Ponte Alta do Bom Jesus , Divisa Bahia – Tocantins, km 11, 11°58’00”S, 46°20’00”W, 660 m, 09 July 1993, (fl., fr.), G. P . Silva et al. 1397 ( CEN, INPA); Rio da Conceição , SC-23-Y-C, bacia do Tocantins, sub-bacia Manual Alves da Natividade , 11°25’29”S, 46°48’45”W, 02 July 2009, (fl.), M. L . Fonseca et al. 6056 ( EAC); ib., 11°25’23”S, 46°44’27”W, 03 July 2009, (fl.), F. C. A . Oliveira et al. 1487 ( ESA) .