The olive (Olea europea) belongs to Oleaceae (the Olive family). It is a semi-tall evergreen tree that is unknown its country of origin. It began to cultivating in Africa about 3,000 BC, and it had been cultivated in the Mediterranean Basin about 600 BC. It was also introduced into Japan in the last days of Edo Era (about 150 years ago). This tree can reach about 9 m in height with many lenticles on the bark. The leaves are lanceolate, thick, leathery with scaly hairs on the both sides. The scented, yellowish-white flowers bloom in the panicles which borne on the axils of new branches from May to July. The fruits are drupes, ripen blackish-purple, and used as a pickled or olive oil.