Poison Sumac — Poison sumac (Toxicodendron vernix or Rhus vernix) is a woody shrub or small tree growing to 7 m (20 ft) tall. All parts of the plant contain a resin called urushiol that causes skin and mucous membrane irritation to humans. When burned, inhalation of the smoke causes diarrhea and other internal irritations.
The head of the tree is round and narrow and the branches slender and rather pendulous; often it is simply a shrub. Small branches and young stems pithy. Has acrid, milky, poisonous juice which turns black on exposure.
The compound leaves are pinnate, 25-50 cm long, with 7 – 13 leaflets; the leaflets are 4-10 cm long and sometimes mistaken for individual leaves. The veins from which the leaflets grow are always red.
The fruit is a small white or grey berry, produced in panicles 10-20 cm long; this distinguishes it from other sumacs which have red berries. Differs from other sumacs in having shorter leaves, leaflets fewer, margins are entire. It is found in wet soils, whereas the others like it dry.