The pistachio (Pistacia vera) is the only commercially grown species in its genus, which belongs to the Anacardiaceae family. Members of the genus Pistacia are among the oldest flowering nut trees and are small to medium in size, and characterized by their ability to exude mastic (plant resin).^1,2 Other economically important plants in Anacardiaceae include cashew (Anacardium occidentale) and mango (Mangifera indica).

Pistachio trees are temperate, deciduous trees adapted to the dry, hot, drought-prone climates of the Middle East.^1,2,3 The pistachio tree can grow to a height of 10 meters (about 33 feet) and has pinnately compound leaves containing three to seven leaflets.^3,4 The trees are dioecious; both male and female pistachio trees produce their own flowers.⁴ Female trees are wind-pollinated and produce green and brown flowers with no petals during the early summer.^1,5 Female pistachio trees produce clusters of nuts…