Poison ivy has three spoon-shaped glossy leaves that are red in the spring, green in the summer, and yellow or orange in the fall. It is more common in the United States in Eastern and Midwestern states.  Poison oak has between three and seven leaves with deep edges around each leaf that are similar to oak tree leaves. It is most common in the Western U.S. and sometimes found in Eastern states, but rare in the Midwest.  Poison sumac has clusters of pointed leaves, with between seven and 13 leaves per stem. It typically grows in wooded, swampy areas and is more common in the Southeastern states.