Introduction This study treats of our midcontinental soils and of the wonderful network of roots within them of a vegetation which has clothed them for untold centuries. This vegetation has almost vanished so great has been the toll of the tractor-drawn plow, overgrazing and trampling, injudicious use of poisonous sprays, building of highways, and other causes. Virgin prairie and undisturbed soil occur in quantity only in areas where limestone underlies a shallow soil and prevents plowing or in

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... sand so unstable that destroying the vegetation with its binding roots is almost synonymous with losing the soil. The many thousands of acres of Flint Hills in east-central Kansas and the 18,000 square miles of Sand Hills in Nebraska are examples. Many years of investigation have permitted thorough examination of grasslands above, in, and below the soil. Several reports have emphasized the individual root habits of grasses, grasslike plants, and forbs. This study is concerned especially with the intimate structure of the continuous network of roots of the several species which dominated and characterized the prairie over an area of thousands of square miles in the central Midwest. This root network is a permanent feature in prairie soils. Years of study have revealed that samples taken in spring, summer, or autumn are the same. The roots of the dominant grasses are long-lived; death and decay of individual roots proceed slowly as does also their replacement by new ones. Many clumps of sod or bunches of grass persist below ground for 15 years certainly and probably for 25.