Cassia fistula, commonly known as golden shower, purging cassia, or Indian laburnum, is a flowering plant in the subfamily, Caesalpiniaceae of the legume family, Fabaceae. The species is native to the Indian subcontinent and adjacent regions of Southeast Asia. It ranges from eastward throughout India to Myanmar and Thailand and south to Sri Lanka and southern Pakistan. It is a popular ornamental plant and is also used in herbal medicine. It is both the national tree and national flower of Thailand. It is the state flower of Kerala in India.
Cassia fistula in Musée Hoangho Paiho
Cassia fistula flower detail
The golden shower tree is a medium-sized tree, growing to 10–20 m (33–66 ft) tall with fast growth. The leaves are deciduous, 15–60 cm (6–24 in) long, and pinnate with three to eight pairs of leaflets, each leaflet 7–21 cm (3–8 in) long and 4–9 cm (1.6–3.5 in) broad. The flowers are produced in pendulous racemes 20–40 cm (8–16 in) long, each flower 4–7 cm (1.6–2.8 in) diameter with five yellow petals of equal size and shape. The fruit is a legume, 30–60 cm (12–24 in) long and 1.5–2.5 cm (0.6–1.0 in) broad, with a pungent odor and containing several seeds. The tree has strong and very durable wood, and has been used to construct "Ehela Kanuwa", a site at Adams Peak, Sri Lanka, which is made of C. fistula (ahala, ehela, or aehaela, ඇහැල in Sinhala ) heartwood.
Leaves in Hyderabad, Telangana, India
In Ayurvedic medicine, the golden shower tree is known as aragvadha, meaning "disease killer". The fruit pulp is considered a purgative, and self-medication or any use without medical supervision is strongly advised against in Ayurvedic texts. Though it has been used in herbalism for millennia, little research has been conducted in modern times, although it is an ingredient in some mass-produced herbal laxatives.