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Laurel Family (Lauraceae)

Important Species

The avocado (Persea americana), also known as the alligator pear, is one of the best known and most economically important species of the laurel family. Avocado is native to tropical regions of the Caribbean, Mexico, and South America. Many different races and varieties are cultivated in southern France, South Africa, Mexico, California, and Florida for their green edible fruits, which are eaten raw or used to make guacamole, a staple of Mexican cuisine.

The avocado fruit can be green or brown in color, depending on the variety, and is rich in oil. The avocado fruit is a drupe with a single large seed in the center. The early Spanish explorers, who observed cultivation of avocados by the Aztecs, thought that the fruit resembled a testicle, and that a man could increase his sexual potency by eating avocados. This belief was based on the "doctrine of signatures," which holds that a plant part that resembles a bodily organ would affect the function of that organ. We now know that the doctrine of signatures has no scientific basis.

The California laurel (Umbellularia californica) is a woody plant which grows from southern California to southern Oregon, and is the only species of this family native to the western United States. It has evergreen, aromatic, elliptical leaves. Under optimal conditions, it grows as a tree and reaches 150 ft (46 m) or so in height, and is shrub-like in appearance. The wood of the California laurel is fine textured, and is sometimes used to manufacture veneer, furniture, and wooden novelties.

There are three species in the genus Sassafras. One is from Taiwan, another from China, and one (Sassafras albidum) is a tree native to the eastern United States. Foresters classify the American sassafras as intolerant because it does not grow well under a closed forest canopy. Indeed, the American sassafras commonly grows in open fields and at the edge of forests. Its leaves are variable in shape, and can be elliptical, two-lobed, or three-lobed. The leaves turn characteristic red in the autumn. Leaves, roots, and twigs are all highly aromatic. Some biologists have suggested that the leaves of Sassafras are allelopathic, in that they chemically inhibit the growth of nearby plants, thus reducing competition. Sassafras tea is made by removing and boiling the bark from the roots. Sassafras oil is used in the manufacture of certain aromatic bath oils.

All species in the Cinnamon genus are aromatic, and most are native to Southeast Asia. Cinnamon is a well-known spice which comes from Cinnamonum zeylanicum, a tree native to Sri Lanka but now cultivated throughout Asia, the Caribbean, and South America. Commercial cinnamon comes from the bark of young twigs, which is stripped off, dried in the sun, and later powdered or used whole.

Another species in this genus, Cinnamon camphora, is the source of camphor. This tree is native to Southeast Asia. Camphor is an aromatic compound derived from the bark and wood of the camphor tree and is used as a medicine to relieve gas pains in the digestive tract, in ointments, and as an insect repellent.


Resources

Books

The American Horticultural Society. The American Horticultural Society Encyclopedia of Plants and Flowers. New York: DK Publishing, 2002.

Audubon Society and staff. Familiar Trees of North America: Eastern Region. New York: Knopf, 1987.

Heywood, V.H. Flowering Plants of the World. Oxford: Oxford University Press, 1993.


Peter A. Ensminger

KEY TERMS

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Bisexual

—Flowers that have functional male and female organs.

Drupe

—A fruit which has a fleshy outer layer, and a hard inner layer which encloses a single seed. A cherry is a typical example.

Pistil

—Female reproductive organ of a flower, which contains ovules that develop into seeds after fertilization by pollen.

Polygamous

—Plants that have some unisexual and some bisexual flowers.

Sepal

—External whorl of a flower which is typically leaflike and green.

Stamen

—Male reproductive organ of a flower that produces pollen.

Unisexual

—Flowers that bear either male or female reproductive organs.

Additional topics

Science EncyclopediaScience & Philosophy: Laser - Background And History to Linear equationLaurel Family (Lauraceae) - Characteristics Of The Lauraceae, Important Species