From The Food Encyclopedia by Jacques Rolland and Carol Sherman
The seed, Pistacia vera, of a small Persian tree, a relative of the cashew, cultivated for at least 3,000 years and gathered in the wild long before that. When ripe, the pistachio's shell opens at one end and is naturally tan in color, but in the 1930s, importers began dyeing the shells bright red to disguise blemishes that occurred during harvesting and to make them more attractive to consumers, a practice rarely seen today because of our modern appreciation for foods in their natural state.
