Olive Family (Oleaceae)

The olive tree (Olea europea) is the best known and most economically important species in this family. This Mediterranean native produces olives and olive oil. Italy and Greece are the major producers of these products. However, olive trees are now cultivated throughout the world, including southern California, South America, and Australia. Olive trees cannot withstand cold winter temperatures.

Olive trees probably originated in Greece, and were later introduced to Italy and elsewhere in the Mediterranean region. Olive oil was well known to the peoples of the Middle East several millennia ago. The Old Testament of the Bible mentions the use of olive oil as an ointment, food, and for burning in lamps. Olive trees are especially well-known in Italy and Greece, where olives and olive oil have been used in the cuisine for thousands of years.

The olive tree has persistent leaves, blooms in the spring, and produces mature fruits in the late autumn or winter. The unripe fruits are green and bitter, while ripe fruits are purple to black in color. The bitterness of the green, unripe fruits can be removed by soaking them in a solution which is alkaline (high pH) or is saturated with salt. Once the bitterness has been removed, green olives are typically pickled in a salt solution for later eating.

Olive oil is made from the ripe, purple fruits. Olive oil has a relatively high percentage of unsaturated fatty acids, and is purportedly healthier than many other vegetable oils. It consists of about 80% oleic acid and 10% palmitic acid. "Extra virgin" olive oil is considered the best, and is prepared by extraction without the use of chemical solvents. "Pure" olive oil is extracted with the use of chemical solvents, and this process removes some of the color and flavor that is so characteristic of extra virgin olive oil.

Olive trees are slow-growing, but can live one thousand years or more. The trunks of mature trees have a very characteristic, gnarled appearance. Olive trees are not used as timber, but the wood has a fine grain and has been traditionally used to make hand-carved implements.

There are about 65 trees and shrubs in the ash (Fraxinus) genus. All species are native to the Northern Hemisphere, and about 18 are native to North America. The leaves of all ash species arise opposite to one another on the stem, and with one exception (Fraxinus anomala), are pinnately compound, in that they consist of numerous small leaflets which arise from a central stalk.

The white ash (Fraxinus americana) is the tallest and most important of the American ashes. It grows throughout the angiosperm forests of eastern North America, and has a characteristic long, straight trunk and leaves which turn yellow or purple in the autumn. The wood of white ash is flexible and light, and is used to make baseball bats and furniture.

Lilac (Syringa vulgare) is native to southeastern Europe, but is widely cultivated throughout the United States and much of southern Canada as an ornamental, flowering shrub. Lilac shrubs produce large, branched inflorescences, referred to as panicles, in early spring. The flowers are purple or white, and have a characteristic aroma. Lilac has escaped form cultivation and become naturalized in parts of temperate North America. This naturalized, European native is the state flower of New Hampshire.

Privet (Ligustrum vulgare) is also a shrub native to Europe. It can take substantial abuse, and so has become the most widely planted hedge plant in the United States. Privet produces flowers in May, and blue-black berries in summer which are eaten by birds. Birds disperse the seeds within the berries, and have thereby naturalized privet through much of the United States.

Golden bell (Forsythia viridissima and several other species of Forsythia) is a cultivated shrub which is native to China. Golden bell has twigs which are yellow-brown in color, and it produces brilliant, yellow flowers in early spring. Like privet, it is a popular hedge plant.