Monographs Details: Cassia curvifolia Vogel var. curvifolia
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
Description:Species Description - Erect shrub or subshrub, usually divaricately much-branched, to 1.5 m. Stems pubescent or puberulent, at least when young; internodes short, 2.0-5.5 mm long. Stipules long-persistent, wholly or partly obscuring the upper stem, ovate-cordate, short-acuminate to obtuse, 2.5-5.1 mm long, 1.6-2.9 mm broad, glabrous and often ciliolate to lightly puberulent. Petiole abbreviate, 0.5-1.0 mm long, puberulent or pubescent; rachis about as long as the petiole. Gland 1, usually urceolate, minute, sessile or on a short thick stipe. Leaflets bijugate, the superior pair longer, joined to rachis by a small arcuate or semi-orbicular pulvinule 0.1-0.3 mm long, falcate- obovate or -oblong, glabrous and often ciliolate to lightly puberulent, subcoriaceous, 2.7-7.8 mm long, 1.4-2.7 mm broad; apex obliquely obtuse to inflexed-mucronate. Flowers axillary, solitary or rarely in pairs; pedicels usually straight, puberulent, 5.4-8.1 mm long and ca. 0.3 mm thick in flower, up to 13.5 mm long and 0.7 mm thick in fruit; bracts 2, puberulent, suborbicular, divergent, 1.9-2.6 mm long, 1.6-2.3 mm broad; sepals lanceolate to broadly lanceolate, 0.6-1.1 cm long, 2.6-3.4 mm broad; petals 0.8-1.3 cm long, 0.6-1.1 cm broad; ovary glabrous or puberulent. Pod narrowly oblong, 2.9-3.5 cm long, 0.4-0.6 cm broad, faces usually cristate over the seeds, glabrous, or puberulent on sutures, or generally puberulent. Seeds 10-16, slightly flattened, 3.1-4.7 mm long, 1.1-1.7 mm broad. Chromosome number: not determined.

Distribution and Ecology - Distribution: Brazil, from the lower north drainage of the Amazon in Pará and Amapá, eastward to Maranhão and Ceará, south through Bahia to Goiás and central Minas Gerais. Occurring in savannas, open woods, and in mountain fields, mostly on sandy soils.

Discussion:

Cassia curvifolia is a well marked species, tolerant of a wide spectrum of environmental conditions, and showing no clear affinity with any other taxon, save possibly C. langsdorffii through an extreme form of the var. lucida.

The leaflets of the var. curvifolia, smallest of those of any taxon in the section Xerocalyx, are usually apiculate in Amazon material, tending to become smaller and more rounded in the drier parts of the northeastern states, and showing no marked distinction further south. The type collection is from the extreme southern portion of the known distribution of this variety. However, it may be expected to occur further southward in the Serra do Espinhaço at Serra do Cipó.

Distribution:Brazil South America| Amazonas Brazil South America| Pará Brazil South America| Amapá Brazil South America| Maranhão Brazil South America| Ceará Brazil South America| Bahia Brazil South America| Goiás Brazil South America| Minas Gerais Brazil South America|