A nectarine is a smooth-skinned peach — genetically the same species, Prunus persica, differing by a single recessive gene that removes the fuzz to leave a glossy, waxy skin in lacquered reds and golds. Often firmer, slightly tangier and more intensely aromatic than a fuzzy peach, its white or yellow flesh is eaten fresh, grilled, poached and baked into tarts through high summer.