It was once thought in Europe that this property could extend to insects, thus walnut trees were planted around barns and homes to repel insects. Pecans have been selectively bred for thin, easy to crack shells. Extensively grown in the southeastern U.S., pecans have become prominent in that region's cuisine. Filberts or hazelnuts are native across north temperate latitudes. Divining rods are still made of hazelnut wood.
Almonds belong to same genus as plums, apricots, peaches.
Unlike its relatives, the almond mesocarp is leathery rather than fleshy. The seed inside the endocarp is consumed, rather than the mesocarp. Pistachio Native to eastern Mediterranean and central Asia. Cultivated for over 3000 years. The practice of dyeing pistachio nuts red began as a means to hide blemishes in the shell.