The wild orange
The wild orange (citrus aurantium), called "Melangolo", is a very rare type of citrus tree. Probably a cross between Citrux maxima (pomelo) and Citrus reticulata (clementine).
Native to the far East, precisely to southern China and to northern Burma, was spread in Europe by the Portuguese and the Arabs in the 10th century. It is thought to believe that in Sicily was brought by Crusaders around the year 1000.