It seems unlikely that any form of agriculture could have been developed from native plants in coastal Peru, for it is as arid a spot as can be found anywhere in our hemisphere. Only an elaborate system of irrigation canals enabled this area to grow extensively corn, beans, and other plants. In the highly developed civilization of the coast—so close to the guano islands—the Indians started the use of fertilizers, which was to be a feature of Peruvian agriculture. The development of irrigation and fertilizer, plus city architecture and the finest pottery in the Americas, spells many years of slowly growing civilization in coastal Peru, and behind these beginnings must have lain centuries upon centuries of earlier agricultural discoveries and improvements in the hinterlands. The only alternative is to accept the diffusion of a full-blown culture across the Pacific. There are those who believe that corn did in fact come from Asia to the Americas. Sauer points out that Asia has more kinds of the wild grasses, Gramineae, akin to corn, _Zea mays L._, than the New World.[28] Another argument is that though the Chinese kept a careful record of the importation of various plants such as tobacco and the opium poppy, there is no mention of corn, implying that they had long been familiar with some variety of it.[29] The botanist Edgar Anderson believes it could have originated in Burma, and could have come across the Pacific “along with cotton, pottery, weaving, etc.”[30] Anderson’s evidence, as he himself maintains, is not conclusive; but it is certainly suggestive. Popcorn is found today among primitive or backward peoples in the remoter parts of Formosa, Sumatra, Java, Borneo, and Burma. From the Naga Hills, where Burma meets Assam, Anderson has had brought to the United States cobs and kernels of popcorn which are identical with the corn found in the earliest graves in Peru. Was this Burmese popcorn carried eastward over the Pacific thousands of years ago and then crossed with some American plant, such as _Tripsacum_, to produce the great variety of larger and more useful types that the Spaniards found? Or was popcorn, imported from the New World, the only maize that the primitive Naga of Burma would cultivate? The argument for a Burmese origin for popcorn is strengthened by some habits of the Naga tribesmen which carry us back to the dispute over diffusion versus independent invention. These people, living in the Stone Age today, follow the agricultural pattern of the pre-Columbian Indian. They burn trees and underbrush to clear their fields. They use a digging stick to plant their corn in the charred rubbish. In amongst the corn they grow cereals and cotton.[31] On the other hand, they could have taken their corn to the New World long before the men of Bat Cave ate maize 6500 years ago.