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Poison Ivy

Poison Ivy
Toxicodendron radicans (L.) Kuntze
(Order Sapindales; Family Anacardiaceae)

Left: Leaves and fruits of Poison Ivy (Kansas Wildflowers and Grasses: Right: Leaves of Poison Ivy (by Kiersten Dixon, June 2011).                                                            

Diagnosis: Understory herbaceous or woody vine
Trunks: The bark is gray and rough and the older it gets it become browner. The aerial roots are red or brown. They can grow from 1 to 3 feet tall or if climbing, they can exceed 50+ feet.  Poison ivy can be a low erect shrub or a climbing vine.
Leaves: The leaves are alternate and palmately 3-leaved. They are egg-shaped to elliptical and range from 1.6 to 6+ inches long and 1.6 to 4+ inches wide. They appear yellow-green and are glabrous to sparsely pubescent. The leaflets come in threes.
Inflorescence: They are in a grape-like cluster that are 1.6 to 4.8 inches long.
Flowers: The flowers are dioecious (male and female flowers are on separate plants).  There are numerous tiny flowers that are cream-colored. There are 5 sepals that are united below and are around 1/20 of an inch long. The veins often appear to be purple or reddish. There are 5 stamens, and the anthers are yellow.
Fruits: The fruits are spherical and they drupe. They are 1/6 to 1/5 of an inch in diameter and are hard and glabrous. They are initially green but turn to a cream/ tan color. They are generally 1-seeded that are yellow.

Flowering Period: This plant flowers in May and the fruits appear in September.

Distribution: Toxicodendron radicans in the United States. From the USDA Plants Database


Distribution Kansas: East 2/3 of Kansas. From the USDA Plants Database


Native Status: Poison ivy is native to the United States and to Kansas.

Habitat: This plant usually grows in dry or moist woods, stream banks, pond and lake margins, roadsides, prairie thickets, and shaded, disturbed areas.

Uses: The Native American tribes would rub this plant on areas already affected by poison ivy exposure and they would use it in a compound to poison arrows.

Toxicity: All parts of the plant can cause an allergic reaction when it comes in contact with your skin. It can cause itchiness, redness, and blisters.

Picture of Toxicodendron radicans leaflets (left) and the blisters on skin (right). From the Prime Health Channel:

Conservation status: Poison ivy is secure.

Etymology: Toxicodendron: means "poison tree." Radicans means "with rooting stems".

Charters, Michael L. 2007. California Plant Names: Latin and Greek Meanings and Derivations.

Great Plains Flora Association 1986. Flora of the Great Plains. University Press of Kansas, Lawrence, Kansas. 724 pp.

Kansas Wildflowers & Grasses:

Weberling, Focko , & Pankhurst, R.J. (1992). Morphology of flowers and inflorescence. Great Britain: University Press, Cambridge.

Image Credits:
Kansas Wildflowers and Grasses.

Picture by Kiersten Dixon, June 2011.

Picture of Toxicodendron radicans leaflets and the blisters it can leave on skin. From the Prime Health Channel.

United States and Kansas Distribution Map from the USDA Plants Database

Submitted by: Kiersten Dixon, July 2011.


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Generated on 2011. This website is continuously updated.
Comments can be sent to Mary Liz Jameson.
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