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POISON IVY
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The classification of poison ivy, a member of the cashew family, Anacardiaceae, is confused because of the plant's highly variable growth forms. Some authorities recognize at least two species of poison ivy, Rhus radicans and R. toxicodendron, while others consider these a single species. (The confusion is added to by referring to the shrubby forms of these plants as POISON OAK.)
Poison ivy is a trailing or climbing woody vine or a shrublike plant, 60 cm to 2 m (2 to 7 ft) tall, containing a poisonous, oily substance called urushiol or toxicodendrol. Its leaves, borne on long stalks 10 to 35 cm (4 to 14 in) long, are each divided into three broad, pointed leaflets. The leaflets, up to 10 cm (4 in) long, are commonly dark glossy green above and slightly hairy below. Small, yellowish or greenish flowers are followed by berrylike drupes.
Poison ivy is native to eastern North America but is now found from southern Canada to Guatemala and in Bermuda, the Bahamas, China, Japan, and Taiwan.
Contamination by poison ivy can occur through direct or indirect contact with the plants or by exposure to smoke from burning plant parts. The resulting DERMATITIS is limited first to the site of contact but may later spread. It can range from itching and inflammation to severe swelling with oozing blisters. Treatment with cortisone creams and ointments helps, once the lesions are dry.
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