Cassia fistula is a deciduous tree that can grow up to 10-20 meters (33-66 feet) tall. It has a straight trunk with smooth, greyish-brown bark and a wide-spreading crown. The leaves are pinnate, with 3-8 pairs of leaflets that are ovate to oblong in shape. The flowers are large, bright yellow, and appear in long, drooping clusters that can be up to 60 cm (2 feet) long. The fruit is a long, cylindrical pod that can be up to 60 cm (2 feet) in length and contains numerous seeds.