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, or sometimes painful rash in most people who touch it. The plant is not a true ivy
Poison SumacPoison sumac (Toxicodendron vernix or Rhus vernix) is a woody shrub or small tree growing to 9 m (30 ft) tall. All parts of the plant contain a resin called urushiol that causes skin and mucous membrane irritation to humans. When burned, inhalation of the smoke may cause the rash to appear on the lining of the lungs, causing extreme pain and possibly fatal respiratory difficulty.