Toxicodendron rydbergii (syn. Rhus rydbergii; Western poison ivy) is a species of Toxicodendron native to most of the United States except the southeastern states. It can be found growing in forests, and other wooded areas, usually near streams and rivers.
It is a shrub that can grow to 1 m (3 ft) tall, rarely up to 3 m (10 ft). The leaves are trifoliate and alternate. The leaflets are variable in size and shape, and are usually 15 cm (6 in) long, turning yellow or orange in autumn. The fruits are small, round, and yellowish.