Senna alata (L.)Roxb.

The genus Cassia was splited in Cassia, Chamaecrista and Senna, according to the following criteria :
 

Distribution of Cassia spp. in the following table :

Global description

Senna alata is an upright shrub that is either hairless or appearing, somewhat woody, short-lived, 1 to 4 m tall. The leaves are alternate and paripinnate, large in size, with leaflets increasing in size from the base to the summit. The bright yellowish papilionaceous flowers are grouped into a large terminal spike-like inflorescence. The fruit is a linear pod with 4 wings and a crenate margin, black in color. It contains many seeds that are lozenge-shaped, brown at maturity.

General habit

Low shrubby, short-lived perennial shrubby plant measuring 1 to 4 m tall. Shrub with an unpleasant odor.

Underground system

The root is a taproot.

Stem

It is cylindrical, solid, ribbed at the base of the petioles.

Leaf

The leaves are alternate and compound, paripinnate. They are broad, yellow-green in color. The petiole thickened at the base, measuring up to 4 cm long. Its base is framed by 2 short, lanceolate stipules, auriculate at the base, 7 to 10 mm wide. The rachis is 40 to 70 cm long. It is of triangular section and without glands. It is flat above, slightly winged, widening before each pair of leaflets. It has 5 to 14 pairs of opposite leaflets, oblong, asymmetrical, rounded, with a rounded and mucronate top. They are shortly petiolulate or subsessiles. The leaflets are of increasing size from the base to the summit, they are 4 to 15 cm long and 2 to 7 cm wide. They are traversed by a dozen or so lateral veins, spreading out on the edge of the limb. The plant is glabrous. In fact, very short hairs are present, at least on young leaves.

Inflorescence

The flowers are grouped into a dense terminal spike-like inflorescence 20 to 35 cm long, a little shorter than the leaves.

Flower

They are bright yellow and about 3 cm wide. The flower buds are half covered by a broad, orange-colored concave bract that is falling down at maturity. The sepals, yellow-orange, are unequal. They measure 12 to 14 mm long. The petals, unequal, obovate form are 15 to 20 mm long. They are bright yellow. The stamens are 7, with 2 of them significantly longer than the others. 4 aborted stamens are also present. The ovary is pubescent sessile, with many ovules.

Fruit

The fruit is a linear pod with mucronate crown, 10 to 25 cm long and 1 to 8 cm wide. It has 4 angles each extended by a wide wing, crenellated edge. It is black in color. It contains many seeds separated by false partitions.

Seed

The seed is compressed, lozenge-shaped, brown in color. It is 5 to 7 mm long.

https://www.gbif.org/fr/species/2956947