Primer: Identifying Plant Medicines

Choosing and using medicinal herbs.

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The common names of many plants have a charm and ­poetry of their own: pearly everlasting, angel’s-trumpet, belladonna, Cupid’s-dart, lady’s-slipper, Queen-Anne’s-lace. Common names place plants in the everyday world because their names are easy to remember and usually easy to pronounce. Some names are descriptive—monkshood, bloodroot, bleeding-heart, goldenrod, jewelweed. Others indicate a plant’s use. Boxwood was used to make decorative boxes; woundworts, to treat wounds; chaste tree, to ensure chastity; crampbark to ease stomach cramps; fleabane to ward off fleas; lungwort to treat lung ailments.

For all their beauty and simplicity, however, common names can be a source of ­extreme confusion. Some plants have more than one common name. Artemisia abrotanum, for example, is known variously as southernwood, old man, lad’s love, and garde-robe. You may know Valeriana officinalis as either valerian or as garden heliotrope. Confusion is also rife when two or more dissimilar plants share a common name. North America boasts several completely ­unrelated plants called snakeroot, and the world has produced many disparate ironwoods, shellflowers, soapberries, honeysuckles, and Devil’s-tongues.

The Importance of Botanical Names

For gardeners, knowing the Latin name of a plant is useful to ensure the identity of what is planted. For those who use herbs medicinally, however, knowing the exact identity of a plant is crucial. To benefit from a medicinal herb, you need to be certain you are using the right plant. Pot marigold (Calendula officinalis), for example, has a long history as a soothing treatment for skin irritations, whereas the popular garden flowers called marigolds (Tagetes spp.) are not effective for this purpose.

Even more important, you must use the correct plant to avoid poisoning yourself or others. What Texans call buttercup is Oenothera speciosa, a member of the evening primrose family that has edible petals. The buttercup of New England is a member of the ranunculus family and is poisonous. To confuse matters even further, evening primrose (O. biennis) is a plant with a long history of traditional medicinal uses, and its essential oil is currently used as a dietary supplement and to alleviate symptoms of PMS. Only the Latin name will assure that you are using the correct plant.

Understanding The Basics

The binomial (“two-name”) system that botanists use for classifying and naming plants was devised by Carolus Linnaeus, an eighteenth-­century Swedish biologist and bot­anist. It describes patterns of relationship and provides a means of organizing the complexity of nature.

The first part of a plant’s name gives its genus, the group to which it belongs and with which it shares many features. Both garlic and onions belong to the genus Allium. A plant’s species name consists of the genus name and a specific epithet, which indicates a group of individuals that have common attributes and can breed ­together. Garlic belongs to the Allium sati­vum species while onions belong to the A. cepa species. The abbreviation of the genus name to the first letter, as in A. cepa for ­Allium cepa, is used only when the genus is clear. Names enclosed in single quotation marks ­following species names indicate a ­single cultivated ­variety, or cultivar. Lady lavender’s botanical name Lav­andula angustifolia is often followed by its cultivar name ‘Lady’ on nursery identification tags.

Many generic names come from the names of mythological figures such as Achillea (yarrow) for Achilles and Artemisia for Artemis. Others honor an individual, perhaps the one who first ­described the plant. Many specific names, or epithets, describe the color of a plant’s flowers, foliage, or other salient characteristic. Albus means “white”; purpurea, “purple”. Rotundifolia means “having round leaves” while odoratum signifies “fragrant”. The ending -us, -a, or -um must agree in gender with that of the generic name—how’s your high school Latin?

Mastering Botanese

Many books are available to help you learn more about plant families. How Plants Get Their Names, by L. H. Bailey (reprint, New York: Dover, 1983), is considered a classic on botanical nomenclature; Dictionary of Plant Names, by Allen J. Coombes (Portland: Timber Press, 1987), is a convenient little dictionary that gives the pronunciation and meaning of botanical names and also provides short descriptions of ­cultivated genera. Here at Herbs for Health, we consult Hortus Third (New York: Macmillan, 1976) and the Royal Horticultural Society’s Index of Garden Plants (Portland: Timber Press, 1994) many times each day.

Test Your Botanical Wisdom

Do you know for whom or what the following genera were named?

1. Asclepias
2. Hebe
3. Heracleum
4. Narcissus
5. Lewisia
6. Daphne
7. Iris

Answers

1. Asclepius (Greek, Asklepios; Latin, Aesculapius) the Greek god of healing
2. Hebe, wife of Heracles and Greek goddess of youth
3. Heracles (Greek, Herakles; Latin, Hercules) Greek mythological hero noted for his great strength
4. Narcissus, in Greek mythology, a beautiful youth who fell in love with his own image, killed himself when he couldn’t reach the person he saw reflected in the water, but was then turned into a narcissus plant
5. Captain Meriwether Lewis (1774–1809), American explorer
6. Daphne, in Greek mythology, a bashful nymph who, when pursued by Apollo, prayed for help and was turned into a ­laurel tree
7. Iris, the Greek goddess of the rainbow