Global description
Leucaena leucocephala is a shrub of 3 to 10 m. Leaves alternate, compound, bipinnate, 15 to 25 cm long. Presence of 3 to 7 pairs of opposite pinnae, 4 to 8 cm long, composed of twelve pairs of linear-oblong leaflets ciliated with acute apex, 0.7 to 2 cm long and 2 to 5 mm wide. White flowers grouped in axillary glomerules, 2 to 3 cm in diameter carried by a peduncle of 2 to 5 cm long. Fruits are pods, flat, brown, long of 8-20 cm and 2 cm wide. The pods are in groups of 5 to 20. Each pod contains between 8 and 18 elliptical seeds, 8 mm long and 4 mm wide, orange brown in color.
Growth habit
Shrub or small tree measuring 60 cm to 10 m high.
Underground system
Like all legumes, roots have nodules of 2.5 to 15 mm diameter, multi-lobed, internal bright pink in color. They allow to fix annually to over 500 kg nitrogen per hectare, but only if the specific rhizobium associated with them is present in the soil. Individuals who do not nodulate are pale-green or yellow and unproductive.
Stem
The woody stem is cylindrical, full and smooth. The finest branches are covered with a loose hairy little gray hairs.
Leaf
The leaves are alternate and compound bipinnate, with 2-7 pairs of terminal divisions with 5-21 pairs of leaflets. Linear-oblong leaflets with very asymmetrical base, pointed end, measuring 7 to 20 mm long and 1.5 to 5 mm wide. They are obliquely arranged on their axis. Their margin is slightly ciliated. They are sometimes slightly pubescent on the midrib of the lower side.
Inflorescence
Hermaphrodite flowers, sessile, are grouped in axillary clusters, carried by a peduncle of 1 to 5 cm long.
Flower
The calyx, in flared tube, ends with five tines. Petals (4 to 5.5 mm long) are free, covered with small loose hairs, pale green in color. The 10 stamens with long filaments (6.5 to 7.5 mm long) end in anthers covered with a loose pubescence.
Fruit
The fruit is an elongated pod, 8 to 20 cm long and 1.4 to 2.1 cm wide, based narrowed in peduncle.
Seed
Seed, ellipsoid to ovoid, 7.5 to 9 mm long and 4 to 5 mm wide.