From the same genus as the common fig tree (Ficus carica), the generic epithet is precisely its Latin name. This genus has more than 1,000 species in tropical and subtropical regions all over the world. The specific epithet refers to its origin in Bengal, a region of the Indian subcontinent divided between Bangladesh and the Indian state of West Bengal, where it is native (also Sri Lanka). The name 'banyan' comes from the Hindi baniya, the name of each of the members of a caste of traders who took their name from these trees, as they apparently set up their markets in the shade of these huge trees.
The banyan emits profuse aerial roots, and grows rapidly, eventually developing into a gigantic tree that can extend for hundreds of metres. Interestingly, like other ficus, it is often born as an epiphyte on a host, then behaves like a strangler fig until its roots take hold and it becomes an independent tree. Moreover, like all fig trees, it maintains a mutualistic relationship with the wasps that pollinate them, which makes it difficult for them to bear fertile seeds outside their native range.
In its native places it is considered a sacred tree by Buddhists and Hindus, and its wood, fibres and leaves are used as food for elephants. They are so large that it is not uncommon for temples, markets and even aerial roots to be re-directed to create structures under their canopy. Buddha is said to have attained enlightenment sitting under a banyan tree.
Perhaps the most famous banyan tree is the one located in the Calcutta Botanical Gardens, some 230 years old and 12,000 square metres in size. Its main trunk is over 12 m in circumference. However, the largest known is Thimmamma Marrimanu, the name of the great banyan tree in the Indian city of Kadiri. Childless couples pray under its canopy, for according to legend they will have a child the following year.