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. 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".