Global description
Sesbania sesban is a perennial shrub of short longevity, 1 to 8 meters high. Only the young parts are pubescent, but then become glabrous when aged. The leaves are alternate, compound, paripinnate, 4 to 12 cm long, stalked, with two deciduous stipules at its base. The leaflets are more or less numerous, 6 to 27 pairs, oblong, 1 to 2.5 cm long. The inflorescences are clusters of 3 to 10 cm, comprising of 2 to 20 yellow papilionaceous, stalked flowers. The yellow standard is sometimes tinged with purple and is has at the base appendages with free end, 2 to 5 mm long. Fruit is a linear pod, sometimes slightly spiral, 12 to 30 cm long, containing 20 to 50 sub cylindrical seeds.
General habit
Sesbania sesban is a short-lived woody shrub, and can measure 1 to 8 m high.
Underground system
Taproot system.
Stem
The stem is cylindrical, solid, glabrous, except the young twigs which are pubescent.
Leaf
The leaves are alternate, compound, paripinnate, 4 to 12 cm long. They are stalked, with two narrowly triangular stipules at the base, 4 to 7 mm long and usually deciduous. The leaflets, 6 to 27 pairs, 1 to 2.5 cm long, and 0,25 to 0,7 cm wide. The leaf blade of leaflets is oblong, base attenuated in corner and slightly asymmetrical, rounded mucronate apex and entire margin. Both sides are glabrous in the older leaves and finely pubescent in the leaves of young branches.
Inflorescence
The inflorescence is an axillary cluster, same length as the leaf at the base of which it is inserted; inflorescence consist of 2-20 papilionaceous flowers.
Flower
Each flower is carried by a stalk, 4 to 12mm long. The calyx is fused in tube, 4 to 5 mm long and ending in 5 acute triangular tines of 1 mm. Corolla, 12-15 mm long, has a yellow standard, sometimes spotted with purple, widely kidney-shaped, 10 to 13 mm long and 12 to 20 mm wide, which has at its base two appendages with free endings, 2 to 5 mm long. The keel is 10 to 15 mm long, the wings are much longer. Nine stamens are fused into a tube by their filaments, one stamen is free.
Fruit
The fruit is a linear pod, 12 to 30 cm long, 2 to 5 mm wide and 1.5 to 2.5 mm thick, slightly arcuate or spiral, ending with a small tip. It contains 20 to 50 seeds. Each loculus measures 4 to 8 mm long.
Seed
The seed is sub cylindrical, 3 to 4 mm long and 2 to 2,2 mm wide, usually mottled.