Senna occidentalis

Author: (Linnaeus) Link

Morphological description (occidentalis Senna compl FT28 )
Erect, subglabrous, foetid herb or undershrub 1.5-2 m tall, usually annual (in any case in seasonal climates). Stipules triangular to linear-acute, more or less falcate, 1-2 cm long.

Leaves paripinnate with 3-5(-6) pairs of leaflets; petiole 3-4 cm long with a relatively large, ovoid gland just above the petiole joint; rachis 8-12 cm; petiolule c. 2 mm. Leaflets membranous, ovate-oblong, more or less unequal-sided, 4-10 by 2-3 cm, apex acuminate, base rounded; upper surface glabrous, lower glabrous or more or less pruinose to finely puberulous.

Inflorescence: Racemes short peduncled (2-4 mm), 2-4-flowered, mainly terminal (occidentalis Senna compl 255216 ); bracts linear-acute, caducous; bracteoles absent; pedicels 5-10 mm.

Flower: (occidentalis Senna fl 255215 )Sepals 5, unequal, outer ones orbicular, c. 6 mm diameter, inner ones ovate, larger. Petals 5, yellow with violet veins, 2 outer slightly larger, 1-2 by l.5 cm, short-clawed. Stamens: 2 long with filaments 5-6 mm long, anthers 5-7 mm long, opening by apical pores; 4 with filaments 2-3 mm and anthers 5-6 mm opening the same way; reduced stamens with 3-4 mm long filaments and tiny anthers; filaments of all stamens straight. Ovary tomentose; style glabrous; stigma lateral, small.

Pods linear, flattened, glabrous or nearly so, brown with pale margins, 10-12 by 1 cm (occidentalis Senna compl 255216).

Seeds 30-40, flat, orbicular, 3-4 mm diameter (occidentalis Senna seed 255217).

Of S American origin, now one of the most widespread of the weedy Sennas found throughout the warmer parts of the world. In the Malesian area an immigrant of long standing.

Habitat & Ecology
In waste places from sea level up to 1200 m, often near and in villages. It flowers throughout the year.

As the English name 'Nigger coffee' indicates the seeds are widely used as a substitute for coffee; this use is also reported from Borneo. From other areas also medicinal uses are reported. See Heyne (1950: 745); Burkill (1935: 478); Quisumbing (1951: 382).