Olive (OUa evroptea), the best known and most valuable of a genus of about thirty species of small trees with very hard wood, which forms the type of the order Oleaceaa to which the ash, privet, and lilac belong. It is probably a native of Syria, and the cultivation of it though not familiar to the writer of the Tliad, is mentioned in the Odyssey. In Greece first grown on the limestone hills of Attica, Italy probably received it from Greece; Gaul, Spain, and possibly Britain, from the Romans; Chili from Spain; Mexico and California, from Jesuit missionaries; and China, Australia and Cape Colony, from still more modern enterprise. It is almost hardy in the south of England, flowering and occasionally fruiting, but not ripening. It is a small tree, seldom more than 30 feet high, of slow growth, but sometimes exceeding 20 feet in girth and seven centuries in age. The wild olive or oleaster (var. sylvestris) has squarish, spinous branches; opposite evergreen, leathery, shortly-stalked leaves, hoary on their under surface; axillary, erect racemes of small white flowers; and small valueless fruit. The calyx and corolla are both four-cleft: there are two exserted stamens, and the ovary is two-chambered and two-styled, each chamber containing one pendulous ovule, though the stony endocarp of the double drupe generally contains but one seed. The cultivated olive (var. saliva) differs in its rounder branches which have no spines, longer leaves, larger fruit, and thicker and more fleshy pericarp. For pickling, the fruits are gathered unripe, soaked in an alkaline lye, and then bottled in brine. For oil, the ripe fruit, the pericarp of which usually yields GO to 70 per cent., is squeezed, yielding virgin oil, and the marc or cake is wetted and re-pressed, and the kernels crushed and boiled to yield a second and third quality. The tree grows best on light or calcareous soils near the sea, and the value attached to its oil as an article of food in countries where butter can with difficulty be preserved made the tree from early times the symbol of peace and good-will.