Like other fig species (including the common edible fig Ficus carica), banyans bear multiple fruit in structures called syncarps. The Ficus syncarp supplies shelter and food for fig wasps and in turn, the trees are dependent on the fig wasps for pollination.
The seeds of banyans are dispersed by fruit-eating birds. The seeds are small, and most banyans grow in forests, so that a plant germinating from a seed that lands on the ground is unlikely to survive. However, many seeds land on branches and stems of trees or on buildings. When those seeds germinate they send roots down towards the ground, and may envelop part of the host tree or building structure, giving banyans the casual name of "strangler fig". The "strangling" growth habit is found in a number of tropical forest species, particularly of the genus Ficus, that compete for light.  Any Ficus species showing this habit may be termed a strangler fig.
The leaves of the banyan tree are large, leathery, glossy green and elliptical in shape. Like most fig-trees, the leaf bud is covered by two large scales. As the leaf develops the scales fall. Young leaves have an attractive reddish tinge.
Older banyan trees are characterized by their aerial prop roots that grow into thick woody trunks which, with age, can become indistinguishable from the main trunk. Old trees can spread out laterally, using these prop roots to cover a wide area. In some species the effect is for the props to develop into a sort of forest covering a considerable area, every trunk connected directly or indirectly to the central trunk. The topology of this structure of interconnection inspired the name of the hierarchical computer network operating system Banyan VINES.
In a banyan that envelops a support tree the mesh of roots growing round the support tree eventually applies very considerable pressure and commonly kills the tree. Such an enveloped dead tree eventually rots away so that the banyan becomes a "columnar tree" with a hollow central core. In jungles such hollows are particularly desirable shelters to many animals.
The name was originally given to F. benghalensis and comes from India where early travellers observed that the shade of the tree was frequented by banias or Indian traders.
In the Gujarati language, banya means "grocer/merchant," not "tree." The Portuguese picked up the word to refer specifically to Hindu merchants and passed it along to the English as early as 1599 with the same meaning. By 1634, English writers began to tell of the banyan tree, a tree under which Hindu merchants would conduct their business. The tree provided a shaded place for a village meeting or for merchants to sell their goods. Eventually "banyan" became the name of the tree itself.
The original banyan, the species 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. There are many banyan species, including:
Looking upward inside a strangler fig where the host tree has rotted away, leaving a hollow, columnar tree.
Due to the complex structure of the roots and extensive branching, the banyan is extensively used for creating bonsai. Taiwan's oldest living bonsai is a 240-year-old banyan housed in Tainan.
Religion and mythology
Banyan trees figure prominently in several Asian and Pacific religions and myths, including:
In Hinduism, the leaf of the Banyan tree is said to be the resting place for the god Krishna.
In the Bhagavat Gita Krishna said "There is a banyan tree which has its roots upward and its branches down, and the Vedic hymns are its leaves. One who knows this tree is the knower of the Vedas." (Bg 15.1) Here the material world is described as a tree whose roots are upwards and branches are below. We have experience of a tree whose roots are upward: if one stands on the bank of a river or any reservoir of water, he can see that the trees reflected in the water are upside down. The branches go downward and the roots upward. Similarly, this material world is a reflection of the spiritual world. The material world is but a shadow of reality. In the shadow there is no reality or substantiality, but from the shadow we can understand that there is substance and reality.
Of all trees I am the Banyan tree, and of the sages among the demigods I am Narada. Of the Gandharvas I am Citraratha, and among perfected beings I am the sage Kapila.(10.26)
The banyan tree is also considered sacred and is called "Vat Vriksha" in Sanskrit, in Telugu known as: 'మర్రి వృక్షము ' ; Marri Vrikshamu and in Tamil known as: 'ஆல மரம்' ; Ala Maram. The god Shiva as Dakshinamurthy is nearly always depicted sitting in silence under the banyan with rishis at his feet. It is thought of as perfectly symbolizing eternal life due to its seemingly unending expansion.
In modern parlance in the Hindi language, it is known as Bargad, Vatavriksh, and Barh.
In Buddhism's Pali canon, the banyan (Pali: nigrodha) is referenced numerous times. Typical metaphors allude to the banyan's epiphytic nature, likening the banyan's supplanting of a host tree as comparable to the way sensual desire (kāma) overcomes humans.
In many stories of Philippine Mythology, the banyan, (locally known as balete or balite) is said to be home to a variety of spirits (diwata and engkanto) and demon-like creatures (among the Visayans, specifically, the dili ingon nato, meaning "those not like us"). Maligno (Evil spirits, from Spanish for 'malign') associated with it include the kapre (a giant), duwende (dwarves), and the tikbalang (a creature whose top half is a horse and whose bottom half is human). Children at a young age are taught never to point at a fully mature banyan tree for fear of offending the spirits that dwell within them, most especially when they are new to the place. Filipinos would always utter a respectful word or two to the spirits in the banyan tree when they are near one, walking near or around it to avoid any harm. Nearly every Filipino believes that provoking the spirits in a banyan tree can cause one great harm, illness, misfortune, untold suffering and death.
Thimmamma Marrimanu is the name of a Banyan tree in Anantapur district, located about 35 km from town Kadiri in the state of Andhra Pradesh, India.It is present in the Indian Botanical Gardens and is more than 200 years old.It is reported to be the world's biggest tree with a canopy of 19,107 square metres. Its branches spreads over 8 acres, and hence was recorded as the biggest tree in the Guinness Book of World Records in 1989
One of the largest trees, named the Great Banyan, is found in Kolkata in India. It is said to be more than 250 years old. Another such tree, named Doda Alada Mara, is found in the outskirts of Bangalore. Doda Alada Mara has a spread of around 3 acres.
One of the most famous of banyan trees was planted on the island of Kabirvad in Gujarat. Records show that the Kabirvad tree is more than 300 years old.
In rural India many villages and towns have a traffic circle, a bus stop and a community gathering place around a big old banyan tree. At night many people come to sit, relax and chat around it. There is usually a small deity placed and worshipped at its foot.
Ta Prohm in the Angkor Wat temple complex of Cambodia is well known for the giant banyans that grow up, around and through its walls.
Several banyans can be found near downtown Hilo, Hawaii. Some of them were planted by celebrities throughout the 20th century and form Banyan Drive.
The first banyan tree in the continental U.S. was planted by Thomas Alva Edison in Fort Myers, Florida in an attempt with Henry Ford to find a more cost-effective way to produce rubber for car tires. The tree, originally only 4 feet (1.2 m) tall, now covers an acre of land on the estate.
One large Banyan tree called Kalpabata is there inside the premises of Jagannath Temple of Puri. It is considered sacred by the devotees and is supposed to be more than 500 years old.
Famous Banyan Treea in Chennai where Theosophical Society is established. Also called as Ala Maram 
A large Banyan tree (Which kind is uncertain by this author) lives in Cypress Gardens, at the Legoland theme park located in Winter Haven, Florida. It was planted in 1939 in a 5-gallon bucket. 
Brian Aldiss, in his novel Hothouse, describes a future Earth where a single huge banyan covers half of the globe, because individual trees discover the ability to join together, as well as drop adventitious roots.
In Salman Rushdie's novel, The Satanic Verses, the village of Titlipur is built around an enormous banyan tree, whose roots cover an area "half a mile in diameter." The tree is intrinsic to the village with some villagers building shelters in it and others living in the foliage.
In The Coral IslandR. M. Ballantyne had Jack Martin give a brief but informative description of a banyan tree they found on the island. This description was the first introduction that many British children had to such a concept.
Cambodian author Vaddey Ratner alludes to a myth about the tree in her 2012 novel "In the Shadow of the Banyan," the story of a child's experience in the horrors of the Cambodian Genocide. 
The Banyan is part of the coat of arms of Indonesia. It is meant to symbolize the unity of Indonesia - one country with many far-flung roots. As a giant tree, it also symbolizes power. Soeharto used it as a logo for his party, the Golongan Karya (Golkar), taking advantage of the deeply rooted belief of his fellow-countrymen and women in the sacred (sakti) nature of the banyan
The Economist magazine features an opinion column covering topics pertaining to Asia named "Banyan".
^Yule, Henry, Sir. Hobson-Jobson: A glossary of colloquial Anglo-Indian words and phrases, and of kindred terms, etymological, historical, geographical and discursive. New ed. edited by William Crooke, B.A. London: J. Murray, 1903.
^See, for instance, the automated search of the SLTP ed. of the Pali Canon for the root "nigrodh" which results in 243 matches, retrieved 22 November 2008 at Bodhgayanews.net.
^See, e.g., SN 46.39, "Trees [Discourse]," trans. by Bhikkhu Bodhi (2000), Connected Discourses of the Buddha: A Translation of the Saṃyutta Nikāya (Boston: Wisdom Publications), pp. 1593, 1906 n. 81; and, Sn 2.5 v. 271 or 272 (Fausböll, 1881, p. 46).