The nectarine is basically a peach without fuzz. Nectarine seeds can actually grow into trees that bear either nectarines or peaches. It is not possible to tell which fruit will grow from a nectarine seed. Due to this characteristic, nectarine branches are often grafted onto peach trees. It is the only guarantee that the tree will produce nectarines.
One medium nectarine contains approximately 67 calories, and is a sufficient source of vitamins A and C.