a swamp plant (Rhus vernix) of the cashew family, with greenish-white flowers, hanging clusters of small grayish fruit, and leaves made up of 7 to 13 leaflets: it can cause a severe rash on contact
See poison sumac in American Heritage Dictionary 4
noun
A shrub (Toxicodendron vernix syn. Rhus vernix) typically of swampy habitats in eastern North America, having compound leaves and greenish-white berries and causing an itching rash on contact with the skin.