Toxicodendron is a genus of woody trees, shrubs and vines in the Anacardiaceae or Sumac Family, including poison ivy, poison oak, and the lacquer tree. All members of the genus produce the skin-irritating oil urushiol, which can cause a severe allergic reaction; hence the scientific name which means "poison tree". Members of this genus are sometimes included in the genus Rhus, although recent molecular evidence points to keeping Toxicodendron as a separate monophyletic genus. They have pinnatel… (More on Toxicodendron)