Member of the Anacardiaceae family. Poison ivy is a climbing, woody vine that grows in wooded areas across much of the central and eastern United States. Leaves are compound, trifoliate, and grow alternately on the plant. Teeth occur on the ends of some cordate/ovate leaves, but they are usually few in number and somewhat rounded. Flowers occur in panicles of small, 5-petaled green flowers, but the vine does not bloom often. Poison ivy causes a painful, itching rash that lasts for several days on skin that comes in contact with its leaves. Blooms May-June.