The scientific name of the tree whose yellow flowers symbolize Thailand’s Songkran season is Cassia fistula.
Cassia fistula is commonly called the golden shower tree because its long, pendulous flower clusters resemble streams of gold. In Thailand, its yellow blooms are known as dok khun and appear around the April New Year period.
The species belongs to the legume family, Fabaceae. It is native to parts of the Indian subcontinent and Southeast Asia and has been widely planted as an ornamental tree in tropical regions.
Cassia fistula is also Thailand’s national tree. Its flowers are associated with prosperity and good fortune, while yellow has special national significance because it is linked with Buddhism and the Thai monarchy. The species is sometimes mistakenly identified as laburnum, but true laburnums belong to a different genus.