Author: (L.C. Richard) Irwin & Barneby
Morphological description
Tree up to 20(-40) m with a trunk 10-60 cm diameter, young parts generally puberulous (multijuga Senna tree 428847). Stipules 3-14 mm long, linear or dilated at base, early caducous.
Leaves (multijuga Senna leaves IK4-17) paripinnate with 18-50 pairs of leaflets; petiole 4-30 mm; rachis with a conical gland between the lowermost pair of leaflets (often early caducous). Leaflets very shortly stipitate, linear-oblong, 2-4(-5) by 0.6-0.8 cm, almost glabrous on upper side, lower pubescent particularly towards base; both ends rounded; apex mucronulate.
Inflorescence: Flowers in terminal panicles up to 30 by 40 cm at the end of leafy branches (multijuga Senna hab 255213 ); peduncles 2-4 cm, puberulous; bracts ovate acute, tomentose, c. 2 mm long; bracteoles absent; pedicels 15-30 mm.
Flower: (multijuga Senna infl 255214 )Sepals 5, when mature greenish-yellow, obovate or orbicular, the outer c. 3 mm, the inner c. 5-7 mm. Petals 5, yellow, usually glabrous, unequal-sized; the lowermost falcate-spathulate, sessile, 2-3 cm long; the four upper with a 4-6 mm long, slender claw, blade 1-2 cm. Stamens 7: 3 with filaments c. 10 mm and anthers 6-7 mm, curved rostrate; 4 with filaments 1-2 mm and with shorter anthers; 3 tiny staminodes; filament of all stamens straight. Ovary shortly stiped, glabrous; style glabrous; stigma subterminal, inconspicuous.
Pods flat, on a 2-9 mm(?) long stipe, broadly linear obtuse, dark brown, septate, usually irregularly indented; the sutures prominently marked.
Seeds 30-60, linear, flattened, glossy, c. 6 mm long.
Distribution
Tropical S America where several varieties have been recognized; var. multijuga has been taken into cultivation and is from the middle of the 19th century found naturalized in S India and few places in the Malesian region, brought by the Dutch from Surinam to Java. Also planted in S Sumatra and on the Philippines. One collection from Flores does not indicate whether it is a garden plant or naturalized.
Habitat
Growing from sea level to c. 100 m altitude.