Rhus radicans, woodlot Willie, poison creeper, three-leaved ivy, markweed
Poison ivy is a trailing or climbing vine common to woodlots, naturalized areas, and property boundaries. It is probably the most common cause of dermatitis to gardeners, campers, and hikers. The irritant oil of poison ivy is found in every plant part (not just the leaves). Poison ivy is famously three-leaved with the terminal leaflet on an extended petiolule. Aerial roots give climbing vines a hairy appearance. Dermatitis can occur from direct contact or from contact with exposed clothing, pets, or smoke from brush burning.