In the religion of the Medes and Persians the cult of trees plays an important part, and with them, as with Assyrians, the symbol of eternal life was a tree with a stream at its roots. Another object of veneration was the sacred miracle tree, which within itself contained the seeds of all.
Marie-Luise Gothein, Walter P Wright (1979). “History of Garden Art: Originally published in two volumes”, p.21, Gardenvisit.com