- The genus Pistacia consists of 11 species and one hybrid of deciduous trees and evergreen shrubs. The evolution of the genus Pistacia and the relationships among its species is presented from paleobotanical, archaeological, historical, and ethnobotanical perspectives. Pistacia trees and their products have accompanied human culture since ancient times. The accumulating data hint at untapped potential of the genus in the environmental, agricultural, and biotechnological fields. Recent modern research has revealed medicinally useful compounds in Pistacia gum, resin, and in solvent extracts. Also, many of Pistacia nutritional qualities are awaiting further research.