Toxicodendron vernix, whose species name means "varnish" in Latin, is the most potent of North America's urushiol-bearing plants, a fact that tends to overshadow its undeniable visual appeal. Growing to 25 feet with a loose, open crown, it carries alternate compound leaves with 7 to 13 smooth-edged leaflets, the rachis and young stems often a deep reddish color that helps with identification. In autumn the foliage turns a spectacular orangish-red, and the dangling clusters of yellowish-white drupes attract birds and rabbits throughout winter. The greenish-yellow flowers appear in spring as long, drooping panicles.

Poison sumac occupies a very specific ecological niche: bogs, marshes, swamp margins, and river banks with acidic soil, where it thrives in conditions that exclude most garden shrubs. It superficially resembles a young ash tree, but ash carries opposite leaves and winged samaras rather than alternate leaves and fleshy drupes. Wildlife value is high, and where human contact is unlikely, the plant performs an important ecological function in wet native habitats. Every part of the plant, at every stage of growth, contains urushiol. Inhaling smoke from burning plant material can cause dangerous inflammation in the lungs. It should never be handled without full protective covering.