The fresh scents of gardens meadows fields and forests are caused by minute droplets of oily liquid produced by plants. These essential oils together with synthetically produced scents form the basis of the perfume industry. Why plants produce essential oils is uncertain. Some attract insects for pollination other ward off parasites or marauding animals. Off the many plants in the world only a few hundred are used to produce essential oils which perfumeries create their perfume. In many places oils are produced at the rate of only a few tons a year. The oils are bought by brokers who sell them to exporters and last of all to the perfumeries who compose their own fragrances which is a difficult to get right and is a delicate art.