Banyan

A banyan, also spelled banian (/ˈbænjən/ BAN-yən), is a fig that develops accessory trunks from adjacent prop roots, allowing the tree to spread outwards indefinitely. This distinguishes banyans from other trees with a strangler habit that begin life as an epiphyte, i.e. a plant that grows on another plant, when its seed germinates in a crack or crevice of a host tree or edifice. "Banyan" often specifically denotes Ficus benghalensis (the "Indian banyan"), which is the national tree of India, though the name has also been generalized to denominate all figs that share a common life cycle and used systematically in taxonomy to denominate the subgenus Urostigma.
Like other fig species, banyans also bear their fruit in the form of a structure called a "syconium". The syconium of Ficus species supply shelter and food for fig wasps and the trees depend on the fig wasps for pollination.
Frugivore birds disperse the seeds of banyans. The seeds are small, and because most banyans grow in woodlands, a seedling that germinates on the ground is unlikely to survive. However, many seeds fall on the branches and stems of other trees or on human edifices, and when they germinate they grow roots down toward the ground and consequently may envelop part of the host tree or edifice. This is colloquially known as a "strangler" habit, which banyans share with a number of other tropical Ficus species, as well as some other unrelated genera such as Clusia and Metrosideros.
The leaves of the banyan tree are large, leathery, glossy, green, and elliptical. Like most figs, the leaf bud is covered by two large scales. As the leaf develops the scales abscise. Young leaves have an attractive reddish tinge.
Older banyan trees are characterized by aerial prop roots that mature into thick, woody trunks, which can become indistinguishable from the primary trunk with age. These aerial roots can become very numerous. The Great Banyan of Kolkata, which has been tracked carefully for many years, currently has 2,880 supplementary trunks. Such prop roots can be sixty feet (eighteen meters) in height. Old trees can spread laterally by using these prop roots to grow over a wide area. In some species, the prop roots develop over a considerable area that resembles a grove of trees, with every trunk connected directly or indirectly to the primary trunk. The topology of this massive root system inspired the name of the hierarchical computer network operating system "Banyan VINES".
In a banyan that envelops its host tree, the mesh of roots growing around the latter eventually applies considerable pressure to and commonly kills it. Such an enveloped, dead tree eventually decomposes, so that the banyan becomes a "columnar tree" with a hollow, central core. In jungles, such hollows are very desirable shelters to many animals.
From research, it is known that the longevity of banyan tree is due to multiple signs of adaptive (MSA) evolution of genes.
The name was originally given to F. benghalensis and comes from India, where early European travelers observed that the shade of the tree was frequented by Banyans (a corruption of Baniyas, a community of Indian traders).
The original banyan, F. benghalensis, can grow into a giant tree covering several hectares. Over time, the name became generalized to all strangler figs of the Urostigma subgenus. The many banyan species also include:
Due to the complex structure of the roots and extensive branching, the banyan is used as a subject specimen in penjing and bonsai. The oldest living bonsai in Taiwan is a 240-year-old banyan tree housed in Tainan.
Banyan trees figure prominently in several Asian and Pacific religions and myths, including the following: