Date of this Version
A magnificent expanse of grassland occupied the central part of North America before the coming of the white man. This paper is the result of a continuous investigation which began in 1916 of a large portion of this prairie. The area of most intensive study included approximately the western third of Iowa and the eastern third of Nebraska. The advent of the great drought of 1933 to 1940 offered an exceptional opportunity to ascertain the responses of native plants to extremely adverse conditions. The role played by rhizomes of grasses in endurance of drought and frequently their recovery from it was very impressive. Indeed only then did the great importance of the part of the prairie in the upper four inches of soil - the prairie sod - become clear. Hence a special study was made in 1961-62 on this portion of prairie vegetation.