abstract:Toxicodendron radicans, commonly known as poison ivy (older synonyms are Rhus toxicodendron and Rhus radicans),USDA Fire Effects Information System: SPECIES: Toxicodendron radicans, T. rydbergii 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.