Cassia fistula

Cassia fistula is a medium-sized and deciduous tree growing up to 10-12 m high with a spreading and irregular crown.

The bark of Cassia fistula is ash-grey-coloured, smooth and warty. The bark flakes off in crusty scales on old trees.

The leaves of Cassia fistula grow alternately on the stem (spirally arranged).
The leaf is compound, paripinnate with a 4-6 cm long petiole and 4 to 8 pairs of large leaflets.
The leaflets are bright green-coloured above and paler beneath. The leaflets are coriaceous and glabrous on both sides.
The leaflets have a 5-6 mm long petiolule.
The leaflet of Cassia fistula is 8-12 cm long and 4-5 cm wide. The shape of the blade is ovate, the apex is acute, the base is cuneate and the margins are entire.
The venation of the leaf is reticulate with a prominent midrib.

The flowers of Cassia fistula are grouped in axillary and many-flowered racemes. These inflorescences are large (up to 15-40 cm long), pendulous and bright yellow.
The peduncle is 4-6 cm long.
The flowers are 5-merous.
The calyx is composed of a cup-shaped, green and pubescent calyx-tube and 5 yellow-greenish calyx-lobes. These calyx-lobes are obovate-orbicular, 7-8 mm long and 6-7 mm wide.
The corolla is composed of 5 bright yellow, obovate, short-clawed and unequal petals. They are glabrous, veined and 2.5-3 cm long and 1.5-2 cm wide with a 3 mm long claw.
The androecium is composed of 10 stamens, 3 of them are as long as the style and 7 are shorter. The stamens have erected filaments and basifixed anthers.
The style is light green, slender and curved. It is 2.5-3 cm long with a simple stigma at the tip.

The fruit of Cassia fistula is a very long and cylindrical pod .
It is smooth, mucronate, up to 50 cm long and about 2 cm across.
These glossy, pendulous and indehiscent pods turn from green to black at maturity.

The seeds of Cassia fistula are in separated compartments with walls about 2-3 mm apart.
The seeds are brown-coloured, flattened, ovate, 8-9 mm long and 7-8 mm wide.

Cassia fistula is widely planted as an ornamental tree. It is an extremely showy tree in bloom.

The wood of Cassia fistula is durable and takes a good and lasting polish. It is used for house and bridge posts, wheels, cart building, agricultural implements, tool handles, rice pounder, turnery and furniture.

The bark is a useful tanning material, known as sumari.

Source : Dastur, 2006, Useful Plants of India and Pakistan