Banyan (Ficus subgenus Urostigma) is a subgenus of many species of tropical figs with an unusual growth habit. They are large trees that usually start life as a seedling epiphytic on another tree (or on structures like buildings and bridges), where a fig-eating bird has deposited the seed. The roots descend over the trunk of the host seeking out the soil below, once they have rooted into this the fig roots rapidly thicken and lignify. Where the fig roots cross each other they fuse, thus creating a lattice around the host tree's trunk. The fig competes with its host for light, water and nutrients, while its roots prevent the host's trunk from growing. Eventually the host dies and rots away, leaving the fig self supporting as an ordinary tree, but with a cage-like hollow tubular lattice of lignified roots instead of a trunk. For this reason banyans are often referred to as strangler figs.
Lost
Banyans have appeared in numerous episodes in Lost. For example, the empty cage of roots around the space where the host tree formerly existed has been used as a refuge against attacks by polar bears and The Security System. The hanging roots are also visible in many jungle scenes.
Numerous Banyans are to be found on Oahu, where Lost is filmed. The Banyan is a non-native and introduced species to the islands.