[AS.] One of the cereal plants from whose seeds bread is made. After Indian-corn, it is the most important of American food plants, and is widely grown in the temperate regions of the remainder of the world. Rice replaces it in importance in the tropics and in China. Wheat is, on the whole, the hardiest of the cereals, though oats are grown in regions where there is not enough heat to ripen the wheat. It is also the most costly of the cereals, yielding less and exhausting the soil more. There are many varieties-autumn and spring, from the times of sowing; red and white, from the colors of the grains; bearded, having ears with awns; beardless, having none; and rivetts, with a coarse straw. An average crop is from 25 to 30 bushels of wheat and 3,000 lbs. of straw from each acre. Silica and potash are especially needed by wheat, and so it grows well on stiff clays which contain much silica. Wheat has never been found growing wild in any part of the world. It was cultivated in Britain in the time of the Romans. It is now chiefly produced in North America, France, Russia, Germany, Italy, Hungary, and India. The United States is the greatest wheat producer, yielding in some years more than 600,000,000 bushels, while the yield of the whole world in 1899 was 2,725,000,000 bushels.