Chamaecrista barbata (Nees & Martius) 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 : 23-26

5. Chamaecrista barbata (Nees & Martius) Irwin & Barneby (1982: 660)

≡ Cassia barbata Nees & Martius (1823: 32) .

Type:— BRAZIL. “ Circa viam Fellsberti, Centurionis , mense ”, December 1816 –1817, (fl.), M.P. zu Wied-Neuwied s.n (lectotype BR867388 !, designed here , isolectotypes BR8674210 !, BR8675231 !, LE00013704 !, MEL256851 !). (Figs. 9 and 10)

= Cassia barbata var. mollis Bentham (1870: 133) . Type:— BRAZIL. Bahia: Jacobina , “ prope Bahiam ”, s. dat., J.S.Blanchet 3666 (lectotype BM000793265 !, designed by Irwin & Barneby (1978: 239); isolectotypes BR0000005904976 !, BR0000005905300 !, C 10011942 !, F0057486F!, G00370908!, G00370926!,G00370914!, G00370926!, GH00053105!, HU00053105!, LE00002288!, MO-714993!, NY00003729!, P02436027!, P02436028!, P02436029!, SI001921!).

Shrubs perennial, 1.5–3 m tall, erect, little or not branched. Root nodules absent. Branches light brown or whitish when young, and dark brown when mature, both setulose-viscous including stipules, petiole and rachis; exfoliating bark in whitish plates. Stipules 2–5 × 0.4–0.5 mm, linear, deciduous. Leaves alternate-spiral, regularly distributed along the stem, plagiotropic; petiole 4.5–7.5 cm long; rachis 2–3.5 cm long; leaflets 2 pairs similar in size, 4.5–9.3 × 2.6–5.5 cm, elliptical or oval-elliptical, apex acute or obtuse, base rounded or oblique on distal pair, papyraceous, discolored, greenish dark, glossy and glabrous on the abaxial surface, pale green, opaque and puberulent on the abaxial surface; margin entire, revolute, not ciliate; secondary veins 4–8 pairs, conspicuous and prominent on abaxial surface. Leafy appendix inter-petioluleabsent. Racemes 15–51 cm long, peduncle 1–3 cm long, 25–110 flowers, lax, terminal or axillary at the termination of the branches, erect with straight axis, setulose-viscous and villous, including pedicel, external surface of bracts, bracteoles and sepals. Bracts 3–4 × 0.4–1 mm, lanceolate, persistent. Bracteoles 2–2.5 × 0.5 mm, lanceolate, persistent. Buds 0.6–1 × 0.6–1 cm, ellipsoid or globoid, apex obtuse. Flowers 1.6–2.8 × 1.8–3 cm; pedicel 0.9–1.3 cm long, straight even when fruited; sepals 0.8–1.1 × 3.5–4.5 mm, elliptical, apex obtuse, yellowishgreen externally; 4 flat oboval or suborbicular petals and 1 falcate-curled inner petal, 1–2 × 1.1–1.6 cm, yellow; stamens 10.5– 7 mm long, anthers barbulate; ovary 3–4 × 1.5 mm, setulose-viscous and puberulent; style 1.1–1.5 cm long, curved in upper third, glabrous. Legumes 4–6 × 0.8–1 cm, linear-oblong, setose-viscous and sparsely puberulent, dark brown. Seeds 5–8, 3–4.5 × 3–4 mm, rhomboid, blackened.

Etymology: —epithet in allusion to the typical barbulate stamens of the species.

Geographical distribution and habitat:— Chamaecrista barbata is an endemic species of northeastern Brazil, occurring in Alagoas, Bahia, Ceará, Pernambuco and Rio Grande do Norte, being here first mentioned for this last state (Fig. 37D). It grows mainly on the edges of arboreal caatingas and gallery forests on latosol, sandy and clayey-sandy soils between 450–1300 meters in altitude.

Flowering and fruiting:—It flowers and bears fruit throughout the year, with the most intense fertile period from February to August.

Conservation status: —Least Concern Species (LC) as to its conservation given its wide area of occurrence (greater than 400,000 km 2) in northeastern Brazil.

Taxonomic history and typification:—Nees & Martius when describing Cassia barbata indicated the collection M.P. zu Wied-Neuwied s.n. from Brazil, but without specifying the locality, and probably deposited in the herbarium M.

Irwin & Barneby in 1978 in their review of Cassiinae pointed out that the possible holotype deposited in the herbarium M was not found anywhere else: “ ... Holotypus, collected by Maximilian zu Wied-Neuwied, not found at Mor or elsewhere... ” ( Irwin & Barneby 1978: 239) and cite those possible isotypes were found in the Leningrad herbarium in Russia (LE), thus leaving the situation of the lost holotype unresolved.

We currently know that Von Martius’ private botanical collection was one of the most important private collections of the 19th century with specimens from all over the world, mainly from Brazil. The Herbarium Martii was acquired by the Belgian government in 1870 and the entire archive, with detailed listings of many of von Martius’ acquisitions, is now preserved in the National Botanical Garden of Belgium. With the digitization of herbaria around the world, it has become easier to access information from historical collections. In view of this information, it was possible to locate, by virtual means, that the collection of “M.P. zu Wied-Neuwied s.n” cited in the protologue of Cassia barbata is deposited in the current herbarium Botanic Garden Meise (BR) in Belgium. However, in the same herbarium, 3 specimens corresponding to the type collection were found, showing that the latter comprised three duplicates. As they know nothing about the whereabouts and composition of the type of C. barbata, Irwin & Barneby in 1978 mentioned that the LE collections found by them would be possible isotypes, but all these specimens must be considered as syntypes, because although in a database since Jstor Global Plants (http://plants.jstor.org/) BR collections are indicated as lectotypes, such a category has never been proposed in valid publications. Therefore, we are here proposing the lectotype of Ch. barbata based on the specimen from the Herbarium of BR ( BR867388 ) because it is better preserved and has flowers and fruits.

Cassia barbata var. mollis was described by Bentham (1870) in Flora Brasiliensis based on the specimen J.S. Blanchet 3666 without herbarium indication. Irwin & Barneby (1978) synonymized it under the typical variety claiming that it did not have significant characteristics for its status. In the same work, they carried out the lectotypification of C. barbata var. mollis , as they found that the same type had several duplicates in different herbaria. We corroborate all the decisions made by Irwin & Barneby (1978), and we admit here a concept for Ch. barbata without infracategories.

Characterization and morphological relationships: — Chamaecrista barbata has a shrubby habit, white or pale yellowish stem or young branches with exfoliating bark in whitish plates when adults, long petioles (3–7.5 cm long), leaves with discolored leaflets with revolute margins, being the largest among the species studied (4.5–9.3 cm long), long inflorescences (up to 51 cm long) and lax as well as barbulate stamens, features shared in part with Ch. brevicalyx . However, Ch. brevicalyx has leaflets 1.5–4.5 cm long, concolorous and with a flat margin and nonbarbulate stamens.

Specimens examined:— BRAZIL. Alagoas: Arapiraca, aprox. 12 km de Arapiraca, na estrada para Palmeira dos Índios, 05 July 1962, (fl.), A . Lima 62-4069 ( F) . Bahia: Andaraí, Nova Vista, 19 June 1984, (fl.), G . Hatschbach 48075 ( NY); ib., Próximo ao trevo de Andaraí-Igatú, antes da ponte, 12°51’10.9”S, 41°18’48.5”W, 371m, 12 May 2017, (fl., fr.), A. O . Souza et al. 2072, 2073, 2074 ( UB, UFG); Caetité, Palmeira , 16 January 1997, (fl., fr.), G . Hatschbach et al. 65844 ( NY); ib., Rodovia Seabra-Andaraí, 22 km do entroncamento em direção a Andaraí , 12°39’47’’S, 41°11’11’’W, 476m, 31 March 2002, (fl.), A. M . Giulietti & R. M . Harley 2080 ( HUEFS); ib., rod. BR 030 , 4,7 km do centro da cidade em direção a Brumado, 29 June 2002, (fl.), A . Flores & R. S . Rodrigues 1024 ( UEC); ib., estrada para Jussiape , 02 February 2005, (fl.), J . Paula-Souza 5313 ( ESA); ib., nos arredores da cidade em borda de caatinga, 14°03’37”S, 42°28’19”W, 816m, 01 August 2017, (fl.), A. O . Souza 2185 ( UB); Encruzilhada, margem do Rio Pardo , 26 May 1968, (fl.), R. P . Belem 3664 ( F, IAN, NY); Iaçu, entre Iaçu e Itaberaba , 19 February 1986, (fl.), A . Fernandes & Matos s. n. ( EAC 14149); Itaberaba, Rod. BR 242 , 12°31’56.5’’S, 40°15’32.7’’W, 270m, 05 February 2005, (fl.), J . Paula-Souza et al. 5469 ( NY); Itaetê, Chapada Diamantina , próximo a entrada do Poço Encantado, 12°98’64”S, 40°97’25”W, 900m, 13 November 2014, (fl.), M. L . Guedes et al. 23073 ( EAC); Ituaçú , 2 km SE da cidade de Ituaçu, 600m, 22 June 1987, (fl.), L. P . Queiroz 1652 ( VIC); Lajedinho, BR-242 próximo do trevo para Wager, Untiga e Morro do Chapéu , 12°28’11.1”S, 41°05’46.9”W, 531m, 09 August 2017, (fl., fr.), A. O . Souza 2232 ( UB); Maracás, a 6 km SW de Maracás, na rod. BA 250 (trecho Maracás / Contendas do Sincorá ) , 900m, 17 September 1978, (fl.), S. A . Mori et al. 11109 ( NY); ib., estrada Maracás-Contendas do Sincorá , 13°27’38’’S, 40°30’48’’W, 10 June 2003, (fl.), M. M . Silva-Castro et al. 615 ( HUEFS); Morro do Chapéu , ca. 23 km E . of Morro do Chpéu , road to Mundo Novo, 100m, 21 February 1971, (fl., fr.), H. S . Irwin et al. 30724 ( UB, F); 27km, S. E . of the town of Morro do Chapéu on the BA052 highway to Mundo Novo, 11°39’S, 41°01’’ W , 800m, 04 March 1977, (fl., fr.), R. M . Harley 19394 ( L / U, UEC); ib., Morrão , 11°35’28’’S, 41°21’27’’W, 1292m, 03 December 2003, (fl.), A. S . Conceição et al. 770 ( BHCB, HUEFS); Pindaí, estrada entre Pindaí e Guanambi , ca. 10 km de Pindaí, 14 July 2001, (fl.), V. C . Souza et al. 25894 ( ESA); Umburanas, 3 km, NW of Lagoinha (5.5 km SW od Delfino) on the side road to Minas do Mimoso , 10°27’00”S, 41°16’00”W, 640m, 05 March 1974, (fl., fr.), R. M . Harley 16763 ( L / U); Wagner, Chapada Diamantina, Pirajá , 12°28’12”S, 41°05’54”W, 11 March 2016, (fl.), M. L . Guedes 24309 ( UFRN) . Ceará: Crateús, RPPN Serra das Almas, 05 June 2002, (fl.), F. S . Araújo & J. R . Lima 1573 ( EAC) . Pernambuco: Belo Jardim, Serra do Genipapo , s. dat., (fl.), M. A . Chase 793 ( NY) ; Rio Grande do Norte: Coronel João Pessoa, Mata Redonda, Serra São José, 19 July 1991, (fl.), M. A . Figueiredo et al. 412 ( EAC) .