Forest Preserve District of Cook County, Illinois
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Plant Odors
Nature Bulletin No. 568-A  May 24, 1975
Forest Preserve District of Cook County
George W. Dunne, President
Roland F. Eisenbeis, Supt. of Conservation

A lawn being mowed, hay curing in the sun, the faint elusive scent of freshly turned soil, the woodsy aroma of the out-of-doors after a summer shower, or the drifting smoke from burning autumn leaves -- these make almost anyone want to stop, shut his eyes and inhale the fragrances that come on the breeze.

Smells are difficult to express in language. Compared with the wealth of words, symbols and other methods for recording sensations of sight, sound and touch, there are only a few which graphically describe odors.

Odors are detected by special sense cells in two patches, about the size of postage stamps, in the uppermost parts of the nasal chambers. Each sense cell is connected with the brain. With ordinary breathing, scents often go unnoticed. Once alerted, however, we sniff, the sensitive patches are ventilated, and odors seem much stronger. Volatile oils such as those of peppermint and flower essences give our most characteristic scents. Most other odoriferous substances are also soluble in oil. The human nose, although much less sensitive than a dog's, can detect unbelievably small quantities of such substances -- often, in a single sniff, as little as one part in billions.

The woods, meadows and wetlands of our forest preserves offer a delightful variety of wild fragrances. Some are friendly and soothing, others exhilarating, and many call up memories of scenes and happenings from the distant past. Some of us have strange likes or dislikes among odors for reasons that lie buried in our subconscious minds.

A few of our local wild flowers have characteristic scents but the great majority are either lacking in distinctive odors or else our noses are too crude and untrained to distinguish differences. Wild roses have a delicate sweet fragrance. So do the opening flowers of wild crabapples. But the beautiful white blossoms of the hawthorn smell like canned sardines. The basswood, black locust, elderberry and buttonbush blooms have rich, rather strong perfumes which attract multitudes of honeybees The grayish-purple flowers of the common milkweed smell sickish and nauseating. Mayapples, when ripe, were dried by our grandmothers to give a pleasant odor to stored clothing and bedding, but the perfume of their flowers is heavy and cloying. For pure enjoyment, nothing can excel the clean refreshing fragrance of the inconspicuous flowers of the wild grape.

Aside from flowers, some of our most interesting odors come from the leaves and other parts of wild plants. Take the mints, for example. A sprig of catnip reminds us of the tea father used to brew on picnics but it makes a cat do flip-flops and purr with ecstasy. Strolling down a woodland trail, a sudden pungent aroma of pennyroyal makes us hunt for the little mint plant we have stepped on. Peppermint and spearmint smell like chewing gum or candy but much fresher and stronger. Crushed leaves of bergamot or horsemint are highly aromatic but a trifle rank.

An unripe walnut makes a fine pocket piece for sniffing purposes. A tangy root of wild ginger makes spicy nibbling Nearby, in the moist woodland, the leaves and fruit of the sweet cicely smell like licorice. The buds and twigs of the spicebush are really spicy. All parts of a sassafras are as aromatic as root beer. The feathery leaves of yarrow are strongly pungent, something like sage. You can take a smelling tour any month in the year.

We already have audio-visual education. Let's have nasal education, too.

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