| Leaves of Three, Let It Be! |
| Location: Oval, across from Faculty Parking Lot |
| The plants on the ground here and
climbing the trees to your left and right are Poison Ivy, Toxicodendron radicans.
Poison Ivy is a member of the family Anacardiaceae, the Sumac or Cashew
Family. Botanists call the leaves "trifoliate" meaning "three leaves" because each leaf has three blades. They are reddish when they emerge in the Spring, turn green during the Summer, and become various shades of yellow, orange or red in the Autumn. In Spring the plants produce clusters of small greenish flowers. The ovaries of the flowers mature into small white fruits near the end of Summer. An oil, urushiol, is produced by all parts of the plant. It can cause a skin rash in about 90% of humans who are allergic to it, but only about half of the population has experienced the rash. Only 1 nanogram (billionth of a gram) of urushiol is needed to cause the rash. Only 1/4 ounce of urushiol would cause a rash in every person on earth! The name of the oil comes from the Japanese word for lacquer. To avoid this itchy rash you must not touch the plant. If you accidentally touch it, you must wash the oil off of your skin with soap as soon as possible. Once you have developed the rash you cannot spread it to other parts of your body or to other people by touching the rash. The rash is spread only by the plant oil. Breathing the smoke from burning Poison Ivy plants can infect your lungs. You may have heard of another poisonous species, Poison Oak (Toxicodendron diversilobum), but thankfully it does not grow in Ohio! -- David Kramer
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