This picture shows you what poison sumac looks like. (Toxicodendron vernix) has a lovely autumn leaf color. Look, but do not touch! Contact with the plant can cause a rash that will be all too familiar to those who know what it is like to suffer with a rash from a related noxious weed, poison ivy.
No need to become paranoid, though. Of the noxious weeds I cover here, poison sumac is perhaps the one that the average person is least likely to encounter in the yard. Why? Because it tends to grow in swampy areas. I had to conduct a web search just to learn where I could find some poison sumac shrubs in New England, so that I could take pictures of them (and inform my readers as to what poison sumac looks like, exactly). My web search led me to an obscure wetland in Andover, Massachusetts. This is a protected area, and the government built boardwalks through it so that the public can take a walk for some exercise and observe nature up close -- all without getting their feet wet! I was rewarded for my rather extreme efforts to locate some poison sumac with a terrific fall foliage display.
Obviously, if it's plants with great fall foliage you wish to grow in your yard, you can make a safer choice than poison sumac. Still tempted by the colorful hues of poison sumac? Try the non-poisonous types of Rhus such as 'Tiger Eyes' (Rhus typhina 'Bailtiger') or plant other shrubs for fall color. Others will prefer to grow fall foliage trees.