Olea /ˈoʊliːə/ is a genus of about 40 species in the family Oleaceae, native to warm temperate and tropical regions of southern Europe, Africa, southern Asia and Australasia. They are evergreen trees and shrubs, with small, opposite, entire leaves. The fruit is a drupe. Leaves of Olea contain Tricho sclereids.For humans, the most important species is by far the Olive (Olea europaea), native to the Mediterranean region, Africa, southwest Asia and the Himalayas. O.