This study was initiated to secure quantitative data on growth characteristics of the major species in the mixed grass prairie of western North Dakota; to determine the extent and range in yearly variations in growth patterns of the species and of the type as a whole; to assess the general influence of climate as a cause for seasonal and yearly variations in growth patterns; and to interpret the data obtained in terms of their possible application to the practical grazing management of these grasslands.This project was supported by the North Dakota Agricultural Experiment Station as a part of project Hatch 9-5: "Native range plants -- their growth and development in relation to the establishment of standards for their proper utilization."