Poison Ivy - It is a climbing or trailing deciduous vine with 3 leaflets. (Leaves of three leave them be.) The toxins, which cause skin inflammation blistering and itching, can be carried in smoke. This is why you should NEVER BURN POISON IVY. The toxins can also be transmitted by objects or animals that have come in contact with the plant. These toxins can stay active on objects or in dead plants for over a year.
Credit: Photo Courtesy of Cornell Cooperative Extension