Monographs Details: Cassia cultrifolia Humb., Bonpl. & Kunth
Authors:Howard S. Irwin
Authority: Irwin, Howard S. 1964. Monographic Studies in Cassia (Leguminosae-Caesalpinioideae). I. Section Xerocalyx. Mem. New York Bot. Gard. 12 (1): 1-114.
Synonyms:Chamaecrista cultrifolia (Kunth) Britton & Killip ex Britton & Rose
Description:Species Description - Annual or short-lived perennial herb11 with erect or ascending, simple or few-branched glabrous stems, usually less than 1 m tall. Stipules often obscuring the upper stem, lanceolate-cordate, acuminate, 1.0-2.5 cm long, 0.4-0.8 cm broad, marginally ciliolate on apical one-third and on basal auricles. Petiole 3.0-7.5 mm long, prolonged beyond nodule as an aristate appendage, the abaxial groove glabrous to pubescent, the abaxial surface strigose or hirsute with distally-directed hairs 0.5-1.5 mm long. Gland scutellate or urceolate, 0.5-1.0 mm broad, sessile or rising from the groove on a short thick stipe. Leaflets unijugate, each joined to petiole by an oblique, linear, black pulvinule, linear-oblong or oblong, oblique or falcate, glabrous, subcoriaceous, 1.5-3.5 cm long, 0.4-1.2 cm broad, usually rather pale gray- or yellow-green; margins hyaline, ciliolate on the apical one-third. Flowers usually solitary, produced in continuous succession except in periods of drought; pedicels commonly arching upward, pilose, 1.8-3.4 cm long and ca. 0.5 mm thick in flower, up to 4.2 cm long and 1.0 mm thick in fruit; bracts 1 or 2, apparently caducous, ovate or narrowly ovate, 1.5-2.5 mm long, ca. 1.0 mm broad; bracteoles subopposite, appressed, linear or linear-lanceolate, 1.5-2.5 mm long, 1.0-1.5 mm broad; sepals linear-lanceolate or lanceolate, glabrous, 1.0-1.5 an long, 2.0-3.0 mm broad; petals 1.0-1.7 cm long, 0.6-1.2 cm broad; ovary pilose with appressed grayish hairs. Pod narrowly oblong, 3.5-5.0 cm long, 0.4-0.7 cm broad, the valves shallowly sulcate between the seeds, appressed-puberulent to pilose. Seeds 15-20, slightly compressed, 3.5-5.0 mm long, 1.5-2.0 mm broad. Chromosome number: n = 7.

Distribution and Ecology - Distribution: Venezuela and eastern Colombia, eastward through the Guianas to Amapá, Brazil, and southward through Rio Branco, Amazonas, and Pará to Mato Grosso and Goiás. Occurring in savannas and low open woods (i.e. "cerrado" in Brazil; "muri" in British Guiana) ; chiefly on sandy soils, at elevations usually less than 3000 feet, except in the region of the Pakaraima Mountains (British Guiana, Venezuela, Brazil) where occasional plants have been taken at ca. 4000 feet. BRAZIL. AMAPA: Curiaú, Municipio de Macapá, 10 July 1951, G A. Black & R. L. Fróes 51—12268 (SI). AMAZONAS: In campo non inundabili "Marajosinho" Rio Negro inferioris, 4 Apr. 1945, A. Ducke 1698 (F,12 GH, MG, NY) ; Rio Negro inferioris Bahia Boiassu, loco Campo Amelia, 23 Mar. 1941, A. Ducke 20431 (SI). GOIAS: Porto Real, w/o date, W. J. Burchell 8489 (K); Porto Real, w/o date, IV. J. Burchell 8598-2 (K); Porto Real, w/o date, IT. J. Burchell 8635-2 (K); Porto Real, w/o date, W. J. Burchell 8679-17 (K); Porto Real, w/o date, W. J. Burchell 8744-3 (K); 102 km. N.E. of Jandaia on road to Goiânia, 6 Feb. 1959, H. S. Irwin 2589 (MICH, NY, R, TEX, UC, US, VIC). MARANHAO: Perto de Carolina. 26 May 1950, J. M. Pires & G. A. Black 2157 (NY). MATO GROSSO: Arica near Cuyabá, 8 May 1903, G. Malme s.n. (S) ; Santa Anna da Chapada, 12 May 1903, G. Malme s.n. (S); Santa Anna da Chapada, 29 May 1903, G. Malme s.n. (S); Santa Anna da Chapada, w/o date, Riedel 485 (K); Near source of Rio Paraguay (Rio Amolar), May 1927, D. Smith 192 (K). PARA: Rio Camará, Pau Grande, Fazenda S. Rita, 8 July 1950, G. A. Black 50-9976 (NY); Maracana, Campo Martins Pinheiro, alem da estrada Cuinarana, 20 June 1958, P. Cavalcante 411 (MG); Montealegre, Sra. Itauajury, 25 Apr. 1926, A. Ducke 16068 (MG); Alto Tapajos, Rio Cururú, Missão Velha, 20 July 1959, W. A. Egler 985 (MG); Vigia, Campo do Caimbé, 26 Aug. 1959, W. A. Egler 1066 (MG); Vigia, Campo do Caimbé, 26 Aug. 1959, W. A. Egler 1066 (MG); Marajó, Jutuba, 1 July 1902, J. Huber 2670 (MG). RIO BRANCO: Bôa Vista, campo de aviacão, 16 Aug. 1951, G. A. Black 51-12617 (SI); Bôa Vista, campo em redor da cidade, 15 Aug. 1951, G. A. Black 51-12533 (SI); Campo da Estrada Bôa Vista-Caracaraí, 2 Sept. 1951, G. A. Black 51-13487 (SI). BRITISH GUIANA: Humirida Mtns., 1863-1864, C. Appun 1408 (K); Orealla Savannah, Corentyne R., Berbice, 6 Jan. 1955, H. S. Irwin 617 (TEX); 4 mi. N. of Lethem, Essequibo, 17 Apr. 1956, H. S. Irwin 1021 (TEX); Orealla, Corentyne R., Sept. 1879, G. S. Jenman 497 (K); Canje R., Apr. 1884, G. S. Jenman 1859 (K); Waranama Ranch, Wiruni-Ituni Savannahs, Sept. 1929, Martyn 113 (K); Berbice, 1837, Robt. Schomburgk s.n. (K); Berbice, 1837, Robt. Schomburgk 401 (BM, F, K, NY); Roraima, 1842-1843, Robert Schomburgk 721 (BM, NY). COLOMBIA: Esmeralda, Río Casanare, Los Llanos, 19-20 Oct. 1938, J. Cuatrecasas 3813a (US) ; w/o locality, 1760-1808, J. C. Mutis 4277 (NY, US). FRENCH GUIANA: Cayenne, Apr. 1946, P. Béna 2386 (U); Maroni, w/o date, M. Melinon 18 (US); w/o locality, 1842, M. Melinon s.n. (BM). SURINAM: Ad onoribo, w/o date, Focke 866 (U); Ad R. Casawinica, June 1846, Kappl. 1926 (U); Powakka Savanne, Sept. 1936, Frickers & Muller 1 (U); Poika savanne, Saramacca, 17 May 1915, Gonggrijp 6 (NY, U); Tibiti savanne, 5 Jan. 1949, J. Lanjouw & J. C. Lindeman 1596 (U); Tibiti savanne, 5 Jan. 1949, J. Lanjouw & J. C. Lindeman 1605 (NY, U); Zanderij I, Savannah B, 10 Mar. 1949, J. Lanjouw & J. C. Lindeman 3273 (NY, U) . VENEZUELA: Sta. Isabel, Bolivar, 1942, F. Cardona 630 (US); L’Orenocjue, w/o date, M. Chaffenjon s.n. (P); Caraccas, w/o date, Lockhart s.n. (K); West from Santa Barbara for about 5 km., Rio Orinoco and Rio Ventuari junction, Amazonas, 23 Feb. 1951, B. Maguire, R. S. Cowan, Sc J. J. Wurdack 32071-A (NY); Hills of Prebo, Vic. of Valencia, Jan. 1920, H. Pittier 9425 (NY, US); Sabanas de Taguanes, Sept. 1942, J. Saer d’Heguert 914 (NY, US); w/o locality, 1868, E. P. Stevens s.n. (NY); Savanna bei Entrada, 23 Dec. 1891, Warming 1 (US); La Paragua, Bolívar, 6 Mar. 1940, L. Williams 12608a (US); Near Laguna Grande just south of L. Pica, La Hormiga Area, between La Pica and Cano Colorado east of Maturin, Monagas, 3 Oct. 1955, J. J. Wurdack & J. V. Monachino 39548 (NY).


Cassia cultrifolia is one of the more stable taxa in the section Xerocalyx, showing relatively slight variability over the whole of its extensive range. The most marked variation is with regard to leaflet and stipule size and pedicel length, but these characters vary independently and present no meaningful regional patterns. Depauperate plants are often found on especially poor soils.

Unfortunately this species is not only rather inconspicuous, especially when not in flower, but also seems, in the present author’s experience, nowhere common. It is not surprising, then, that herbarium material is rather scant, especially from the south drainage of the Amazon and the northeastern portion of Brazil south of Pará.

C. cultrifolia seems most closely related to C. diphylla; certain forms of the latter have narrow leaflets which superficially resemble those of C. cultrifolia. However, in the few localities where both species were observed in relative proximity, no evidence of hybridization was seen.


Distribution:Brazil South America| Amapá Brazil South America| Amazonas Brazil South America| Maranhão Brazil South America| Mato Grosso Brazil South America| Pará Brazil South America| Colombia South America| French Guiana South America| Suriname South America| Venezuela South America|