Toxicodendron vernix

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• proper noun A taxonomic species within the genus Toxicodendron — poison sumac; a tall shrub or a small tree, from 2–7 m tall, bearing leaves with 7–13 untoothed leaflets in a feather-compound arrangement, found in swampy, open areas. Like poison ivy it causes urushiol-induced contact dermatitis. It is considered the most toxic plant species in the United States.