What sumac plants cause rash?

The sumac plants that can cause skin rashes are primarily poison sumac (Toxicodendron vernix), which contains urushiol, an oil that triggers allergic reactions in sensitive individuals. Unlike non-toxic sumacs, poison sumac typically grows in wet, wooded areas and has clusters of white berries. Contact with its leaves, stems, or berries can lead to itching, redness, and blisters. It's important to differentiate it from non-toxic sumac species, which do not pose these health risks.