Poison Ivy (Eastern Poison Ivy)
Kingdom: Plantae, Division: Tracheophyta, Class: Magnoliopsida, Order: Sapindales, Family: Anacardiaceae, Genus: Toxicodendron, Species: Toxicodendron radicans · Anacardiaceae (Cashew or Sumac family) · Compound (trifoliate with three leaflets), deciduous
Species
Toxicodendron radicans
Leaf Type
Compound (trifoliate with three leaflets), deciduous
Family
Anacardiaceae (Cashew or Sumac family)
Shape
Ovate to elliptical with acute apex, margins variable from entire to coarsely toothed or lobed
Size
Leaflets approximately 2 to 4 inches long, which is typical for mature plants
Margin
Entire, coarsely toothed, or irregularly lobed
Arrangement
Alternate
Rarity
Very Common
Color & Pattern
Medium to dark green on the upper surface, paler beneath; turns brilliant shades of yellow, orange, and red in autumn
Venation Pattern
Pinnate with a prominent central midrib and branching lateral veins
Texture & Surface
Smooth to slightly pubescent, often with a slightly glossy appearance on the upper surface
Description
Toxicodendron radicans is a notoriously adaptable woody vine or shrub that climbs trees using hairy aerial roots. It produces characteristic compound leaves composed of three leaflets. The plant is well known for its vibrant fall foliage and its ability to cause severe contact dermatitis in humans.
Key Features
Leaves of three ('Leaves of three, let them be'), alternate arrangement, variable leaflet margins, aerial rootlets on climbing vines, and clusters of whitish-gray berries in winter
Habitat
Thrives in a wide variety of habitats including woodlands, forest edges, clearings, along fence rows, and disturbed soils; highly adaptable to both sun and shade
Geographic Range
Native to eastern and central North America, extending from Canada through the United States to Mexico
Condition Notes
Good condition with minor insect feeding damage and typical natural spotting on mature summer leaves
Interesting Facts
The plant produces urushiol, an oil that can remain potent on surfaces for years; even dead vines can cause severe allergic reactions when handled or burned
Medicinal & Uses
No modern safe uses for foraging or medicine due to the extreme toxicity of urushiol; historical homeopathic uses are obsolete
Ecological Role
Provides valuable winter food resources, such as berries, for many bird species and cover for small wildlife, playing a normal role in native forest ecosystems
Similar Species
Boxelder (Acer negundo) which has opposite compound leaves, and Virginia Creeper (Parthenocissus quinquefolia) which typically has five leaflets
Foraging Tips
Look for the classic three-leaflet pattern and woody vines clinging tightly to tree trunks via dark, hairy rootlets. Avoid contact entirely.
Toxicity Warning
Highly Toxic. Contact with any part of the plant (leaves, stems, roots, sap) transfers urushiol oil, causing severe skin rashes, blisters, and intense itching in sensitive individuals. Never burn the plant.