For wild, uncultivated species of bananas, trees are reproduced by the same process of other seeded plants: seeds are planted and then germinate, followed by the maturation of the plant. After the plant matures, pollen tubes, zygotes and embryos are formed that eventually become the fruit itself. The fruit contains seeds that begin the cycle anew; however, with bananas specifically, this process is different for cultivated or farmed varieties.
As opposed to the seedless varieties found in most grocery stores, uncultivated (or wild) bananas have large amounts of seeds interspersed in the flesh of the fruit, which makes eating the banana difficult and unpleasant. For this reason, seedless varieties of bananas have been selectively bred into the more familiar fruit with which most people are familiar.
Though wild banana trees follow the typical path of reproduction, banana trees grown to produce fruit for consumption are seedless, making them more palatable to consumers. Consequently, this makes them infertile. For this reason, seedless banana trees are reproduced by using what is called a pup. A pup is the banana tree's fruit at a very early stage in its development. The pup can be separated from the tree and planted elsewhere. This forms a rhizome, which becomes a new tree that eventually produces seedless fruit.