The nectarine is a mutation of the peach which is why the trees, leaves, and pinkish white blossoms are extremely similar. It only really becomes clear whether a tree is actually a nectarine tree when the fruit starts to develop. In terms of taste, however, they are somewhat more acidic than peaches.
Nectarines were first known of in Europe in the 17th century, and then became popular in the 19th century as a result of propagation. They belong to the Prunus genus within the rose family (Rosaceae) and, today, are mainly harvested in the USA, Chile, South Africa, Italy, France, Spain and Greece.