Poison ivy is quickly identified as having only three leaflets per leaf and small, hair-like roots growing along the entire length of the stem. When poison ivy grows prostrate as a groundcover, leaves remain small. When it grows vertically (up a tree trunk), the leaves grow much larger and in the summer, they get bumps (galls). All parts of poison ivy can produce an allergic reaction. If you are allergic and know you have poison ivy in your garden, apply a protective cream to your skin prior to working in the yard. Do not burn poison ivy plants.
You may want to refer to this link for photos: Poison Ivy: Toxicodendron radicans
