Family Anacardiaceae – Cashew & Sumac Family
Poison ivy is undergoing an explosive surge in range, prevalence, and toxicity worldwide, due to the particular effects of increased CO2 concentrations in Earth’s atmosphere. 
Notable plants in a diverse family include: Poison ivy, Cashew, the Sumacs, Pistachio and Mango. Trees, vines, or shrubs each with small flowers, highly poisonous, sometimes foul smelling resinous or milky sap.
Important commercial crops in this family include the cashew and pistachio nuts, mangos, and imbu (Spondias). Resins, oils and lacquers are obtained from plants in genus Toxicodendron. There are about 600 species in 70 genera.
1. Susan Carol Hauser, A Field Guide to Poison Ivy, Poison Oak, and Poison Sumac: Prevention and Remedies
2. NATIONAL AUDUBON SOCIETY, National Audubon Society Field Guide to North American Trees