Chamaecrista megacycla ( Irwin & Barneby 1978: 153 ) Mendes & Silva In Mendes et al. (2020:178)

Mendes, Thainara Policarpo, Souza, Alessandro Oliveira De & Silva, Marcos José Da, 2021, Taxonomic review of Chamaecrista sect. Absus subsect. Absus ser. Paniculatae (Benth.) H. S. Irwin & Barneby (Leguminosae, Caesalpinioideae), Phytotaxa 495 (1), pp. 1-64 : 33-36

6. Chamaecrista megacycla ( Irwin & Barneby 1978: 153) Mendes & Silva In Mendes et al. (2020:178) . ≡ Chamaecrista claussenii var. megacycla ( Irwin & Barneby 1978: 153) Irwin & Barneby (1982: 655) . ≡ Cassia claussenii var. megacycla Irwin & Barneby (1978: 153) . Type: — BRAZIL. Goiás: Cerrado, Serra do Caiapó, 50 km S. of Caiapônia, road to Jataí, 1000 m, 27 June 1966 fl., fr., H. S. Irwin, R. Souza, J.W. Grear & R. Reis dos Santos 17832 (holotype: UB!; isotypes: C10011955!, F, GH, K000555586!, K000555587!, MO, P, RB, S, SI, UC1418637!, US 00001421!). Figs. 20 and 21

Shrubs 0.90–1.70 m tall, erect or pendent distally, branched; Stem and branches glabrous, cylindrical, erects, stem and adult branches light brown, stem and young branches yellouish or yellowish-green and waxy. Stipules 1.2–1.5 × 0.3–0.4 mm, lanceolate, pubescent, caduceus. Leaves 7.5–15.4 cm long, distributed at the base of the branches, ascending; pulvinus 2–5 mm long, discreetly dilated, not striated; petiole 5.2–9.4 cm long, cylindrical and sulcate above, setulose below; rachis 3.5–5.7 cm long, cylindrical and sulcate above; pulvinule 1.5–5 mm long, visibly dilated; leaflets (1) 2 pares, coriaceous; blades 4–10 × 4.1–9.5 (–11.2) cm, orbicular and suborbicular, margin entire and setulose, plane, surface abaxial and adaxial glabrous, base asymmetrically rounded, apex rounded or obtuse, with mucron, dark-green, opaque; venation with, secondary veins 5–10 pairs, yellow; Panicles 0.8–1.2 m long, with 6–14 secondary axis, not geminate, terminal, with flowers laxly distributed, slightly pendent, setulose, darkish. Bracts 1.1–2.4 (–4) × 0.5–1.2 mm, lanceolate, apex obtuse, margin entire, yellow, pubescent, caduceus. Bracteoles 0.8–1.4 × 0.2–0.3 mm, lanceolate, apex acute, margin entire, light green, ciliate, caduceous. Buds 1–1.3 cm long, ovoid, light green, glabrous, apex obtuse. Flowers 4–5.6 cm long; pedicel 1.9–3.9 cm long, robust, glabrous; sepals 1–1.4 × 0.5–0.6 cm, elliptic, apex obtuse, glabrous, light green or yellowish; petals 1.8–2.5 × 1.2–2 cm, obovate, with the adaxial petal like a standard, one of the inner petals coiled in the androecium; stamens 5.7–7 mm long, filaments 0.5–1 mm long, anthers 5.2–6 mm long, not mucronulate at apex. Ovary 3–5 × 0.8–1 mm, glabrous; styles 1.1–1.8 cm long, glabrous. Legume 4–5 × 3–4 cm, glabrous light green to vinaceous, narrow-oblong. Seeds 5.9–6 × 3.9–4 mm, orbicular, darkish, smooth, and glossy.

Representative Specimens Examined: — BRAZIL. Goiás: Caiapônia, Cerca de 27 km de Caiapônia pela GO- 184, 17°4’37’’S, 51°46’9.1’’W, 747 m 16 April 2016, T. P . Mendes & J. A . Oliveira 77 ( UFG), 78 ( UFG), 79 ( UFG); ib., 23 August 2016, (fl., fr.), T. P . Mendes & R. C . Sodré 334 ( UFG), 335 ( UFG), 336 ( UFG), 337 ( UFG); Cavalcante, RPPN Serra do Tombador, 8 km da sede em direção a Cavalcante , 13°39’06’’S, 47°49’48’’W, 780 m, 26 July 2014, (fl., fr.), M. F . Simon & L. M . Borges 2493 ( CEN); Campinorte, Cerca de 11 km de Campinorte pela BR-153, 14°13’14.4’’S, 49°0.7’55.8’’ W , 747 m 19 May 2016, (fl., fr.), T. P . Mendes & J. A . Oliveira 98 ( UFG), 99 ( UFG), 100 ( UFG); Colinas do Sul, estrada entre Niquelândia e Colinas do Sul , 14°25’20’’S, 48°0.5’46’’ W , 27 May 2016, (fl., fr.), T. P . Mendes & J. A . Oliveira 141 ( UFG), 142 ( UFG), 143 ( UFG), 144 ( UFG), 145 ( UFG), 146 ( UFG), 147 ( UFG), 148 ( UFG), 149 ( UFG), 150 ( UFG); Jaroaquara, Serra de Santa Rita no Distrito de Jaroaquara , 22 May 1971, (fl.), J. A . Rizzo 6344 ( UEC, UFG); ib., 24 July 1971, (fl., fr.), J. A . Rizzo 6570 ( ESA); Niquelândia, 3,7 Km Sul da Go-237; a 5 Km da sede da Fazenda Ouro Fino, Área de Influência da UHE Serra da Mesa , 14°33’S, 48°58’W, 500 m, 07 July 1992, (fl.), G. P . Silva et al. 1127 ( CEN, HUEFS); ib., Fazenda Córrego d’Anta, após a a Escola Divino Pai Eterno, 4 Km seguindo sempre à direita pelas estradinhas 14°26’S, 48°58’W, 430 m, 05 August 1992, (fl.), B. M. W . Teles et al. 1889 ( CEN); ib., Córego da Serra, Encosta de Colina , 16 July 1993, (fl.), G . Hatschbach 59612 ( CEPEC, MBM); ib., da Rodovia Uruaçu – Niquelândia (Cerda de 60km de Uruaçu) em direção a Barro Alto, 14°32’22’’S, 48°41’52’’W, 600 m, 15 July 2000, (fl., fr.), V. C . Souza , J. P . Souza & G. O . Romão 23973 ( UEC), 23974 ( UEC); ib., 4 km em direção a Muquém, 14°27’48.9’’S, 48°10’56.6’’W. 23 June 16, T. P . Mendes & J. A . Oliveira 201 ( UFG), 202 ( UFG), 203 ( UFG), 204 ( UFG), 205 ( UFG); Uruaçu, Fazenda Baião, Local próximo a antiga moradia dentro da Fazenda, a norte da sede mais ou menos 23 Km da cidade de Uruaçu, 03 August 1992, (fl.), B. M. W . Teles et al. 1776 ( CEN); ib., BR 153 km 232 entre os municípios de Uruaçu e São Luiz do Norte , 14°46’30.7’’S, 45°16’8.1’’W, 27 May 2016, T. P . Mendes & J. A . Oliveira 331 ( UFG), 332 ( UFG), 333 ( UFG) . Mato Grosso: Ribeião cascalheira, 200 km ao N de Xavantina on the Xavantina-São Felix Road, 12°56’30.8”S, 51°49’27.1”W, June 1968, (fl.), Santos , R. R . 1644 (UB, NY).

Distribution and ecology: —Species distributed in Goiás, Mato Grosso and Tocantins (Fig. 27B), growing in cerrados ralos or cerrados típicos (Fig. 1C), pastures and in the transition between cerrados típicos and campos sujos, on clay, sandy soils with gravel in plane areas or on mountain slopes between 430 and 1000 meters of elevation.

Flowering and fruiting:— Collected with flowers and fruits between April and August.

Etymology: —The specific epithet “ megacycla ” refers to large and circular leaflets of the species.

Conservation status: —Although this species forms populations with less than 50 mature individuals, its conservation was considered as Least Concern (Least Concern, LC), as it has an area of occurrence of 81,327 km 2 and grows in various places unsuitable for agricultural crops, preserved and difficult to access, such as, for example, the slopes or hill tops on the southern slope of the Chapada dos Veadeiros region, Colinas do Sul and Niquelândia municipalities.

Morphological relationships and characterization: —Species recognized by the following characters: subshrubby habit up to 1.70 m tall, stems and waxy branches, leaves with two pairs of leaflets located only at the base of the plant, large (up to 10 × 11.2 cm), divaricate and with a setulose margin, the petiole and conspicuously set stem below, long panicles (0.8–1.2 m long), with shapely, waxy inflorescence and in many cases larger than their vegetative part, ciliate bracteoles, buds and fruits glabrous. Its morphological relationships with Ch. cyclophylla have already been discussed in the comments of the latter.