Chamaecrista tocantinensis Mendes & Silva In Mendes et al. (2017: 326)

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 : 52-55

10. Chamaecrista tocantinensis Mendes & Silva In Mendes et al. (2017: 326) . Type: — BRAZIL. Tocantins: Ponte Alta do Tocantins, on the road TO-255, east side of the municipality, ca. 8 km towards the municipality of Mateiros , 10°41048.30 S, 47°2908.60 W, 328 m, 20 July 2016, (fl., fr.), T. P. Mendes & J. A. Oliveira 312 (holotype: UFG!; isotype: NY!). Figs. 32 and 33

Small trees 0.70–1.10 m tall or shrubs, 0.90–1.75 m tall, erect. Stems with bark conspicuously longitudinally fissured, cinereous to darkish. Branches cylindrical to angulate; adult branches discreetly fissured, brownish; young branches greenish to green-yellowish, viscous and resin-dotted, including petiole, rachis, axis of inflorescences, pedicel, external surface of stipules, bracts, and bracteoles, ovary, and fruits. Stipules 2.6–6.5mm long, linear or subulate, caducous. Leaves 7.1–12.5 cm long, distributed along the branches or in its terminations, plagiotropic; pulvinus 1–1.8 mm long, discreetly dilated, not striated; petiole 4.6–6.9 cm long, cylindrical, not sulcate above; rachis 6–11.2 cm long, cylindrical, not sulcate above; interfoliolar segments 1.2–3.2 cm long; pulvinule 2.6–6.5 cm long; leaflets 5–7 pairs, decreasing in size from the base to the tip, coriaceous; blades 2.8–6.5 × 2.6–6.5 cm, widely ovate or orbicular, or more rarely cordate, margin entire, plane, glabrous, surface abaxial and adaxial glabrous, base discreetly asymmetrically obtuse or shallowly cordate, apex obtuse or rounded, sometimes with a short mucron, light green, opaque; venation with secondary veins 3–5 pairs, secondary, yellowish or greenish. Racemes 21.3–63 cm long, terminal, solitary or in clusters of up to three, or sometimes axillary and always solitary; or panicles 36.5–90 cm long, with 2–5 secondary axis, terminal, both types of inflorescence delicate, with flowers laxly distributed, erect to pendent, exserted from the foliage. Bracts 0.9–1.1 × 0.2–0.4 mm, broadly lanceolate, apex acute, margins entire, yellowish, persistent. Bracteoles 0.4–0.8 × 0.2–0.4 mm, deltoid, apex acute, margins entire, yellowish, persistent. Buds 5–7 mm long, widely ovoid to ellipsoid, yellowish to green-yellowish, with purplish pigmentation, glabrous, apex obtuse. Flowers 2.2–3.5 cm long; pedicel 1.2–2.2 cm long, slender, cylindrical, straight; sepals 1.2–1.8 × 0.6–1 cm, broadly elliptic, apex obtuse, greenish yellow to yellowish, sometimes with discreet purplish pigmentation; petals 0.8–1.4 × 0.5–0.9 cm, predominantly obovate, the adaxial one similar to a standard, one of the inner petals small (0.8–0.9 mm long), the other coiled in the androecium; stamens 3.2–4 mm long, filaments ca. 1 mm long, anthers 2.2–3 mm long, oblong, pubescent on lateral sutures, mucronulate at apex; ovary 1.8–2.2 × 0.8–1 mm, oblong, villous; styles 7.8–9 mm long, glabrous. Legume 2.5–4.2 × 0.4–0.7 cm, oblong, green to vinaceous. Seeds 5.4–5.5 × 2.9–3 mm, orbicular, light to dark brown, smooth, glossy.

Representative specimens examined: BRAZIL. Goiás: São Domingos , 13°36’44.1″S 46°17’22.8″, 05 November 2013, C. B. R . Munhoz et al 7665 ( UB) . Piauí: Ribeiro Gonçalves, Estação Ecológica de Uruçui-Uma , 7°33’32.6″S, 47°14’33.5″, 28 July 1983, (fl., fr.), A. Fernandes s.n.; ib., Brejo das Meninas, 7°33’32.6″S, 47°14’33.5″, 03 September 1981, (fl., fr.), A . Fernandes s.n. ( EAC 10702) . Tocantins: Novo Acordo, at the top of the steep access to the mouth of the Vermelho River , 10º22’58″S, 47º22’31″W, 303m, 7 July 2008, (fl., fr.), E. R . Santos et al. 1692 ( HUTO); ib., 11 July 2009, (fl., fr.), E. R . Santos & A. C . Pereira 1763 ( HUTO); Ponte Alta do Tocantins, on the road TO-255, east side of the municipality, ca. 8 km towards the municipality of Mateiros , 10°41′48.3″S, 47°29′8.6″W, 328 m, 20 July 2016, (fl., fr.), T. P . Mendes & J. A . Oliveira 313 ( UFG), 314 ( UFG), 315 ( UFG), 316 ( UFG), 317 ( UFG), 318 ( UFG), 319 ( UFG), 320 ( UFG), 321 ( UFG), 328 ( UFG), 329 ( UFG), 330 ( UFG) .

Distribution and ecology: — Chamaecrista tocantinensis was cited by Mendes et al. (2017) only for the state of Tocantins (municipalities of Novo Acordo and Ponte Alta do Tocantins), in the region of Jalapão. However, has its distribution here extended to the states of Goiás and Piauí (Fig. 36B). It grows in a cerrados ralos, cerrados típicos (Fig. 1D) and campos limpos on sandy soils between 303 and 328 meters.

Flowering and fruiting: —Collected with flowers and fruit from July to September.

Etymology: the specific epithet “ tocantinensis ” alludes to the fact that the typus collection of the species was collected in the state of Tocantins.

Conservation status: — Chamaecrista tocantinensis is being considered as Least Concern (LC) according to IUCN criteria (2012), as it has large populations (more than 40 individuals), is distributed over an area greater than 55,287 km 2 and because it was collected in more than five locations.

Morphological relationships and characterization: —Species more morphologically similar to Ch. orbiculata which it shares the arboreal habit, the stem with longitudinally fissured bark, in addition to the orbicular leaflets. However, it differs from the latter mainly because of the leaves with decreasing leaflets from the base to the apex, with an asymmetrical obtuse base or with little cord, pulvine measuring 2–6 mm in length, small flowers (2.2–3.5 cm long) with delicate pedicel, ovary, inflorescence axis and fruits with resin punctuations, and flowers in racemes or panicles. Ch. orbiculata has leaves with uniform sized leaflets, with an asymmetrical-rounded base, pulvine measuring 1–1.8 mm long, large flowers (4.5–6.6 cm long) with robust pedicel, ovary, axis of inflorescence and fruits without resinous punctuation, inflorescences of panicle.