Monographs Details: Cassia langsdorffii Kunth ex Vogel var. langsdorffii
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.
Family:Caesalpiniaceae
Synonyms:Chamaecrista langsdorffii (Kunth ex Vogel) Britton ex Pittier, Cassia borbonioides Vogel
Description:Species Description - Erect shrub or subshrub to 1.5 m, simple or with few to many branches, or, in wind-swept mountain fields, many-branched and sub-humifuse; the dorsal side of young parts often purplish. Stipules large, foliaceous, obscuring the glabrous upper stem, lanceolate to ovate, acuminate or more rarely obtuse and mucronate, auriculate or sub-hastatulate, 1.2-2.3 cm long, 0.4-0.8 cm broad, glabrous, coriaceous, the margins hyaline. Petiole 0.5-1.2 cm long, glabrous or the adaxial groove sometimes finely pubescent; rachis 0.2-0.4 times as long as petiole. Gland 1, oblong to suborbicular, ureolate or shallowly scutellate, 1.0-1.4 mm long, 0.9-1.1 mm broad, sessile or elevated on a short thick stipe. Leaflets bijugate (very rarely trijugate), the inferior pair somewhat broader and usually longer, the superior pair usually clivergent-falcate, joined to rachis by a small arcuate black, brown or yellowish pulvinule 0.7-1.5 mm long, linear to lanceolate, acuminate to acute or rounded, somewhat oblique, especially at the base, glabrous, coriaceous, 1.8-3.4 cm long, 0.2-0.6 cm broad, commonly gray-green with grayish or yellowish venation and margin; margin usually strongly hyaline, the apex acute, obtuse or less commonly rounded. Flowers mostly solitary, produced intermittently; pedicels straight or arching upward, glabrous, 1.8-2.6 cm long and ca. 0.4 mm thick in flower, up to 3.7 cm long and 1.2 mm thick in fruit; bracts 1 or 2, broadly deltoid or crescentiform, 0.8—1.3 mm long, 1.1-1.5 mm broad; bracteoles subopposite, lanceolate or narrowly ovate, usually appressed, often diverging in fruit, 3.2-5.1 mm long, 1.6-2.7 mm broad; sepals lanceolate, glabrous, 1.2-1.7 cm long, 0.1-0.6 cm broad; petals about as long as sepals, 0.7-1.4 cm broad; ovary sparsely to copiously sericeous with grayish appressed hairs. Pod firm, narrowly oblong, 3.5-6.1 cm long, 0.6-0.9 cm broad, faces often strongly cristate over seeds, glabrous or sparsely appressed-pubescent. Seeds slightly flattened, 4.0-6.2 mm long, 1.1-1.7 mm broad. Chromosome number: n ==7.

Distribution and Ecology - Distribution: South Brazil, in southern Mato Grosso and Goiás, south through Minas Gerais and São Paulo to Paraná, and in adjacent Paraguay. Occurring in savannas and open woods (cerrados) on sandy clay soil, and in open places on mountain slopes and summits, at elevations of 500-3000 feet.

Discussion:

In his treatment of Cassia in Flora Brasiliensis, Bentham was obviously troubled by C. langsdorffii, and, in recognition of the variability he discerned, appended 4 unnamed forms, presumably of potential varietal rank. Because of the relative paucity of material at his disposal, his lack of field experience in Brazil, and perhaps his interest in not cluttering the nomenclature with questionable taxa, Bentham fortunately refrained from designating these variants names. Careful examination of material used in support of them as well as additional material has shown that because Bentham weighed leaflet width rather heavily as a character of C. langsdorffii and did not envisage this character as a variable one in C. tetraphylla and C. chartacea as well, 3 of the variants he enumerated are, on the basis of total characters, in fact more closely related to these 2 latter taxa.

The first form, based on Blanchet 2536, from Bahia, and Martins s.n., from Manaus, is, when one considers the small stipules, short pedicels, large flowers, and pubescent fruit, very closely related to C. tetraphylla var. brevipes. The former specimen, however, is especially striking and is scarcely different from Gardner 2828, from Pernambuco, which Bentham cited, together with Martius s.n. from Minas Gerais (not seen), as the basis for his second form, distinguishing it from the first by "foliolis angustissimis acutis submarginatis," narrow stipules, and flowers of moderate size. Close examination shows that these specimens (i.e. Blanchet 2536 and Gardner 2828) are virtually alike; accordingly they are treated under C. tetraphylla var. linearis in the present treatment. Spruce. 3646, from the Orinoco, which Bentham felt was similar to the Brazilian material in form 2, is, like the Manaus material of Martius, close to C. tetraphylla var. brevipes.

Burchell 3574, from São Paulo, which documents the 3rd form, and which Bentham recognized as similar to the Sellowian type of C. borbonioides, clearly falls within the limits of variability of the here described C. langsdorffii var. langsdorffii. Although rather small in stipule and leaflet dimension, it agrees very closely with the typical variety.

In Burchell 4280, also from São Paulo, and the basis for the 4th form, Bentham felt he had found an intermediate between C. langsdorffii and C. gracilis. For reasons mentioned in the present treatment of the latter species, this intermediacy, if indeed it is tenable, lies elsewhere, most probably with C. chartacea, largely on the basis of the slender petiole, small glancl, membranaceous leaflets, and slender pedicels, and more particularly with C. chartacea var. tenuicaulis because of the slender stems and decumbent habit.

This is not to deny variability in C. langsdorffii var. langsdorffii, even as here conceived. As will be discussed under C. chartacea, a number of forms found in Minas Gerais and Goiás are indeed perplexing, but should, at least until both C. chartacea and C. langsdorffii become better known, be included with C. chartacea, detailed study of characters showing affinity to lie more clearly in the direction of that taxon. Specimens of C. langsdorffii var. langsdorffii from the southern portion of Serra do Espinhaço, especially Serra do Cipó, in Minas Gerais, show considerable variability in foliar characters. For example, Duarte 1983 and Irwin 2524a have ovate stipules, rounded leaflet apices, and short pedicels, but in other respects agree closely with the typical variety.

 

Distribution:Brazil South America| Goiás Brazil South America| Mato Grosso Brazil South America| Minas Gerais Brazil South America| Paraná Brazil South America| São Paulo Brazil South America| Paraguay South America|