Olive trees, Olea europaea, originated in the Mediterranean Basin and today are cultivated in Mediterranean climate regions around the world.
Olive flavors and textures are strongly influenced by how ripe the fruits are when harvested. Green olives are made from unripe fruits. When left on the tree to ripen, all olive fruits eventually darken, and from those we make black olives.
A cultivar is a plant either selected from the wild or bred to have a specific characteristic. In the case of olives, cultivars are usually selected for size, flavor, oil production, or texture of the fruit.
Different cultivars of olives have been developed for fruit and oil production, but all of the olives we consume are variants of this same species.