Toxicodendron radicans, commonly known as poison ivy (older synonyms are Rhus toxicodendron and Rhus radicans), is a poisonous North American plant that is well known for its production of urushiol, a clear liquid compound found within the sap of the plant that causes an itching, irritation and sometimes painful rash in most people who touch it. The plant is not a true ivy (Hedera).
Poison ivy can be found growing in any of the following forms:
- as a trailing vine that is 10–25 centimetres (3.9–9.8 in) tall
- as a shrub up to 1.2 metres (3 ft 11 in) tall
- as a climbing vine that grows on trees or some other support