A shrub or climbing vine, older stems of vines fastened to trees by a dense growth of aerial rootless and often climbing into treetops. Common to abundant in and at the edges of wooded areas, and containing an oil capable of causing intense itching and watery blisters through contact with the skin. Leaves variable in size, divided into 3 leaflets on an often reddish tinged petiole; the terminal leaflet symmetric, roughly ovate but lobed and toothed, larger than the lateral ones; lateral leaflets asymmetric, lobed and toothed on the side toward the leaf base and usually only toothed on the opposite side, turning orange and red in autumn. Flowers greenish white, inconspicuous, in clusters up to 4 inches long. Fruit cream to white, sometimes a dull yellow, spherical, about 1/4 inch in diameter, conspicuous on bare twigs in winter.