Poison Ivy (Toxicodendron radicans): Description of the plant, the skin reaction it causes, uses, control, and photos.
Poison Ivy Information: Botanical information about Toxicodendron, from Botanical.com
Poison Oak: Botanical, toxicological and ethnobotany information, with photographs, on Toxicodendron diversilobum and other related and unrelated plant species containing the toxin urushiol.
Toxicodendron toxicarium: Eastern poison-oak. Information on taxonomy, botanical and ecological characteristics, geographic distribution, fire ecology, and management.