The oldest known remains of corn cobs may be in Tehuacan, Mexico, dating back 7,000 years. Most corn historians consider a wild grass called Teosinte one of modern corn's primary ancestors. Corn is one of the most diverse grain crops. Nature by itself and man working with it have produced many types of corn. Corn is generally classed as to kernel endosperm characteristics.
Endosperm refers to a seed's nutritive tissue, surrounding and absorbed by the embryo.
The six most common corn types include flint, flour, dent, pop, waxy, and sweet. A seventh is called pod or tunicate corn, which may have endosperms like the other six. Pod corns differ from the others in that each individual kernel Is enclosed in a glume or husk. Popcorns are basically small-kerneled flint types. Waxy corn carries a gene which results In the production of 100 percent amylopectin, i.e., starchy pectin.