What is Poison ivy?
[[file:Toxicodendron radicans, leaves.jpg|thumb|right|Poison ivy in spring, [[Ottawa]], [[Ontario]]]] '''Poison ivy''' (''Toxicodendron radicans'') is a [[vine]]. It is well-known for causing a rash. The rash is [[urushiol]]-induced contact [[dermatitis]]. Urushiol is the chemical in the ivy that hurts the skin. The plant grows the urushiol [[defense against herbivores|so animals will not eat it]]. The rash itches and it can cause pain. The vine's leaves come in threes, with a shiny appearance caused by the oil on the leaves. It is a common [[weed]] in the eastern [[North America]] and parts of [[China]]. [[Category:Anacardiaceae]]