Nopales are the leaves of the prickly pear cactus. These leaves are rich in nutrients and heal the body inside and out. They grow all over the valley, in fact, you may have some in your yard. The useful cacti are either green or purple and are roughly the size of the palm of a person's hand. Prickly pear often called opuntia or cactus pear. Together with maize and agave, prickly pear has been a staple food. All species of cacti are native to North and South America, with the exception of mistletoe cactus, which is native to Africa. More than 7 million acres in the country are dedicated to growing the plant.