Poison Ivy

Biography

Poison ivy is a type of allergenic plant in the genus Toxicodendron which is native to East Asia and North America. Formerly considered a single species, Toxicodendron radicans, poison ivies are now generally treated as a complex of three separate species: T. radicans, T. rydbergii, and T. orientale. They are variable in appearance and habit, and despite its common name, poison ivy is not an ivy (i.e., Hedera type), but rather a member of the cashew and pistachio family (Anacardiaceae). Though T. radicans is commonly eaten by many animals and the seeds are consumed by birds, poison ivy is most often thought of as an unwelcome weed. It is well known for causing urushiol-induced contact dermatitis, an itchy, irritating, and sometimes painful rash, in most people who touch them. The rash is caused by urushiol, a clear liquid compound in the plant's sap. Despite the name of “poison” ivy, urushiol is not a true poison and is an allergen, to which 15% of people are resistant.

Bio from Wikipedia