Probably native to Iran and adjacent areas, pistachios have been carbon-dated to 6760 BC. This nut of antiquity is one of two mentioned in the Old Testament. Pistachios are said to have featured in the fabled Hanging Gardens of Babylon, built about 700 BC by King Nebuchadnezzar to cheer up his wife, Amytis, who found the flat Babylonian landscape dreary.

Pistachios grow well in arid countries such as Turkey, Syria, Afghanistan and Iran. They also turn up in Pakistan and India, as well as in Mediterranean Italy, Tunisia and Greece. In the last 30 years or so, the pistachio has found new homes in California, New Mexico and Arizona. The rugged pistachio, cousin to the mango, cashew, sumac and poison oak, thrives in heat and grows well in rocky, dry soil. It reaches a height of 25 feet and its holly-like leaves grow in threes, its nuts in clusters resembling grapes.

The pistachio's uniqueness, certainly among nuts, is its green color. Food historian Waverly Root has asserted that the green of the nut opened up the possibility of inserting the color green naturally into desserts, an area of cuisine previously green-deprived. The early people of Persia used several nuts in desserts, the Arabs copied them, and the Europeans under Arab control in Spain during the Middle Ages in turn copied them. So green crept into after dinner pleasures. Most familiar of these today is probably pistachio ice cream and pistachio nougat candy.

Pistachios are high in iron and potassium and are about 20 percent protein.