Chamaecrista claussenii ( Bentham 1840: 79 ) Irwin & Barneby (1982: 655)

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 : 22-26

3. Chamaecrista claussenii ( Bentham 1840: 79) Irwin & Barneby (1982: 655) ≡ Cassia claussenii Bentham (1840: 79) . Type: — BRAZIL. Minas Gerais: Cachoeiras do Campo, 1839, fl. P. Claussen s.n. (lectotype: K! [000555589], designated here, photo IPA! [IPA1044], NY! [NY1491]; isolectotype: K! [K000555590]). Figs. 12 and 13

Shrubs 1–2.5 m tall, erect or pendent, branched or not. Stem and branches waxy and glabrous, stem and adult branches brown or vinaceous, stem and young branches green. Stipules 0.8–1 mm long, lanceolate, caduceus, glabrous. Leaves 11.2–17.2 cm long, regularly and laxly distributed along the branches, ascending; pulvinus 4–9 mm long, discreetly dilated, striated; petiole 4.5–8.9 cm long, cylindrical and sulcate above; rachis 5.2–9.2 cm long, cylindrical and sulcate above; interfoliolar segments 1.9–4.3 cm long; pulvinule 1.5–2.5 mm long, visibly dilated; leaflets (2) 3–5 (6) pairs, coriaceous; blades 3–6.3 × 2.1–5.1 cm, oval, margin entire, plane, glabrous, surface abaxial and adaxial glabrous, base asymmetrically cordate, apex obtuse, with mucron, light green, opaque; venation brochidodromous, secondary veins 9–11 pairs, yellow or vinaceous. Panicles 48–80 cm long, with 14–18 secondary axis, not geminate, terminal, with flowers laxly distributed, erect to pendent, glabrous or setulose on apex, including pedicel, external surface of sepals, ovary and fruits, waxy, exserted from the foliage. Bracts 1.2–2.2 × 0.6–0.8 mm, lanceolate or deltoid, apex acute, margin entire, yellow, pubescent, caduceus. Bracteoles 0.8–1.4 × 0.2–0.3 mm, lanceolate or deltoid, apex acute, margin entire, yellow, pubescent, persistent. Buds 0.7–1.2 cm long, ovoid, green with purplish pigmentation, glabrous, apex obtuse. Flowers 4.6–5.3 cm long; pedicel 2,3– 4 cm long, robust, cylindrical; sepals 1–1.3 × 0.6–0.9 cm, elliptic or oblong-elliptical, apex obtuse, yellow with purplish pigmentation; petals 1.8–2.5 × 1.4–1.7 cm, obovate, with the adaxial petal like a standard, one of the inner petals coiled in the androecium; stamens 5–8 mm, filaments 1mm long; anthers 4–7 mm long, not mucronulate at apex. Ovary 0.3–0.4 × 1.2–1.6 cm, glabrous; styles 1.2–1.5 cm long, glabrous. Legumes 3.4–4.9 × 0.5–0.8 cm, glabrous, narrow-oblong, light green to vinaceous. Seeds 5–7 × 3–4 mm, ovoid, darkish, smooth, and glossy.

Representative specimens examined: — BRAZIL. Federal District: Brasília, Jardim botânico de Brasília . Ca. de 20 km a SE de Brasília 15°52’15.7”S, 47°50’00.7”W, 03 July 1985, Equipe do jardim Botânico de Brasília 436 ( HEPH); ib., Rodovia de acesso à Fazenda Sucupira a 300 m do portão, 1 April 1998, (fl.), G. P . Silva , A. B . Sampaio 3876 ( ESA) . Goiás: Caldas Novas, Serra de Caldas Novas, 27 June 1970, (fl.), Rizzo 5334 ( ESA); ib., Alto da Serra de Caldas Novas , 29 August 1970, (fl.), J. A . Rizzo 5490 ( ESA); ib., Parque Estadual de Caldas Novas , 22 November 2000, (fl.), H . D. Ferreira 364 & R. H . Camilo 16 ( ESA); ib., 31 July 2008, (fl., fr.), J. O. V . Iglesias , M. N . Barbosa , I. A. R . Parreira et al. 70 ( ESA); ib., 02 August 2008, Iglesias, M. N . Barbosa , I. A. R . Parreira ( ESA); Cidade Ocidental, Estrada para o povoado Mesquita , 16°04’29”S, 47°53’42’’W, 11 June 2002, (fl.), M. L . Fonseca , R. C . Mendonça , F. C. A . Oliveira et al, 3456 ( UB); Corumbá de Goiás, Cerrado acima do Salto de Corumbá, 19 June 2014, (fl.), A. O . Souza et al 980 ( UFG); ib., BR 414 , ca. 8 km de Corumbá sentido Cocalzinho de Goiás, 15°52’22’’S 48°46’55’’W 907m, 26 May 2016, (fl., fr.), T. P . Mendes & J. A . Oliveira, 127 ( UFG), 128 ( UFG), 129 ( UFG), 130 ( UFG), 131i ( UFG), 132 ( UFG), 133 ( UFG), 134 ( UFG), 135 ( UFG), 136 ( UFG); Morrinhos, Estrada de Morrinhos para Caldas Novas , 25 July 1970, (fl.), J. A . Rizzo 5412 ( ESA); Pirenópolis, Serra dos Pirineus , 15°49’13’’S, 48°54’21’’W, 15 August 2002, (fl.), M. L . Fonseca , C. W . Fagg , E . Cardoso et al, 3514 ( UB); ib., cerca de 10km de Pirenópolis em direção à Corumbá de Goiás, 15°55’42’’S, 48°51’03’’W, 1100m, 14 July 2000, V. C . Souza , J. P . Souza , G. O . Romão 23851 ( ESA) . Minas Gerais: Arinos , RPPN Arara vermelha-proprietário: Miguel Ângelo Guella (local próximo à porteira de entrada); ib., Entrada para Chapada Gaúcha-MG 15°26’41.6’’S, 45°48’46.7’’W, 820 metros, 26 May 2004, (fl.), M. L . Fonseca ; F. C. A . Oliveira & E . Cardoso 5427 ( ESA); Francisco Dumont, Serra do Cabral, Rio Preto , 16 May 2001, (fl.), G. & M . Hatschbach 72196 & E . Barbosa s.n, ( BHCB); Joaquim Felício, Km 486 da BR-135, entre os municípios de Joaquim Felício e Bocaiúva , 17°40’44’’S, 44°5’25’’W, 841m, 10 July 2016, (fl., fr.), T. P . Mendes , J. A . Oliveira 292 ( UFG), 293 ( UFG), 294 ( UFG), 295 ( UFG), 296 ( UFG), 297 ( UFG) .

Distribution and ecology: —Endemic to the Brazilian Central Plateau (Federal District, Goiás and Minas Gerais), (Fig. 17 C) growing in thin or cerrado denso (Figs. 1D and E) in sandy or clayey soils with or without outcrops of rocks, between 700–1300 meters of elevation.

Flowering and fruiting: —It blooms and bears fruit between the months of May and November.

Conservation status: —Species considered Least Concern (LC), for having an area of extension of 115,773 km 2, and is a taxon relatively common across the Cerrado of central Brazil.

Typification: — Cassia clausseni was described by Bentham (1840) based on a collection of P. Claussen whose place of occurrence was not indicated. More than a century later, Irwin & Barneby (1978) admitted it as a variety after the discovery of Ch. claussenii var. cyclophylla and Ch. claussenii var. megacycla . In this same work, the authors discussed the typification of the typical variety and reported that the collection on which Bentham (1840) based the description of his new species came from Cachoeiras do Campo, Minas Gerais, and a fact probably due to the authors having found collections of the Kew herbarium whose labels included P. Claussen as a collector. These same authors, ( Irwin & Barneby 1978), indicated the Claussen 866 collection as belonging to the typical variety, belonging to the GH, P and S herbariums. Analyzing these collections, we realized that they were collected in different periods, and therefore, it could be admitted as a duplicate of the other in the isotype modality as informed by the authors. In this way, we realize that the species must be lectotypified not only by the mistake made by the authors previously mentioned, but also by the fact that there are two duplicates of the P. Claussen s.n. in the Kew Herbarium (Fig. 14), under different Barcodes. We chose here as the lectotype of the species the collection under Barcode K000555589, because it is more complete and corresponds faithfully to the protologue.

Morphological relationships and characterization: — Chamaecrista claussenii is mainly recognized for its waxy stems and inflorescences and long panicles (up to 80 cm long), which makes it similar to Ch. rigidifolia . However, it differs from the latter in that it has a petiole measuring 4.5–8.9 cm long. (vs. 2.4–5.3 Ch. rigidifolia ), leaves sparsely distributed on the stem with 4–6 pairs of oval leaflets (vs. densified with 2–4 pairs of oblong-elliptical or oboval leaflets), effuse panicle with secondary solitary axes (vs. compact with geminate secondary axes) and elliptical or oblong-elliptical sepals (vs. lanceolate or oval-lanceolate). The species shares the long inflorescences with Ch. megacycla and Ch. cyclophylla , however, they are differentiated by characters such as leaves distributed throughout the plant in Ch. claussenii and Ch. cyclophylla (vs. distributed at the base of the plant in Ch. megacycla ); petiole glabrous in Ch. claussenii and Ch. cyclophylla (vs. conspicuously setulose in Ch. megacycla ); two pairs of leaflets in Ch. cyclophylla and Ch. megacycla (vs. 3–6 (7) pairs in Ch. claussenii ); leaflets orbicular in Ch. cyclophylla and Ch. megacycla (vs. oval in Ch. claussenii ); margin of leaflets glabrous in Ch. claussenii and Ch. cyclophylla (vs. setulose in Ch. megacycla ); base of leaflets asymmetrically rounded in Ch. cyclophylla and Ch. megacycla (vs. asymmetrically cordate in Ch. claussenii ); panicles glabrous or setulose at apex in Ch. claussenii , glabrous or viscosesetulose on the secondary axes in Ch. cyclophylla and setulose in Ch. megacycla ; buds ovoid and glabrous in Ch. cyclophylla and Ch. megacycla (vs. ellipsoid and setulose in Ch. cyclophylla ; pedicel setulose in Ch. claussenii and Ch. cyclophylla (vs. glabrous in Ch. megacycla ); and seeds darkish in Ch. claussenii and Ch. megacycla (vs. brownish in Ch. cyclophylla ).