The orange (specifically, the sweet orange) is the fruit of the citrus species Citrus × sinensis in the family Rutaceae. The fruit of the Citrus sinensis is considered a sweet orange, whereas the fruit of the Citrus aurantium is considered a bitter orange. The orange is a hybrid, possibly between pomelo (Citrus maxima) and mandarin (Citrus reticulata), which has been cultivated since ancient times. More: en.wikipedia.org.