Introduction ... .. .. . .... . .. .. .. . .. .. . .. .. . .. .. .. . .... . .. .. . 227 History and Occurrence in the United States 227 Description and Growth Habit 228 Habitat .... 229 Phenology .. 230 Viability, Germination, Dispersal, and Longevity of Seed 233 R oot System ... .. .. . .. .. . .. .. .. . .. .. . .. .. . .. .. .. . .. .. . .. .. . 235 Ecological Role 236 In Stable Communities 236 A Component of Deteriorating Ranges 237 Disturbance from Grazing ......... 237 Disturbance from Fire 239 Abandoned Cropland 241 Secondary Succession of Cheatgrass Ranges 242 Grazing Value 245 Grazing Capacity 246 Forage Production 246 Nutritive Value 249 Palatability and Proper Use 250 Soil-Plant Relations 250 Incidence of Smut and Other Disease 252 Opportunity for Control 253 By Burning 253 By Cultivation and Seeding 256 By Use of Chemicals 258 Literature Cited 258