Toxicodendron rydbergii

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Toxicodendron rydbergii
Toxicodendron rydbergii UGA1208036.jpg
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Rosids
Order: Sapindales
Family: Anacardiaceae
Genus: Toxicodendron
Species: T. rydbergii
Binomial name
Toxicodendron rydbergii
(Small ex Rydb.) Greene

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.[1]

Unlike Toxicodendron radicans (Eastern poison ivy), which often appears as a trailing or climbing vine, Toxicodendron rydbergii 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. On the compound trifoliate leaves, the two leaflets opposite each other are typically asymmetrical, in contrast to the terminal leaflet which always shows bilateral symmetry. The fruits are small, round, and yellowish.[1]


All parts of this plant contain Urushiol, which can cause severe dermatitis in some individuals.


  1. ^ a b USDA Fire Effects Information System: Toxicodendron radicans, T. rydbergii