Over much of that great natural resource called the Western Range, comprising some 728 million acres (1), species of Stipa and Orysopsis are prominent and important members of the grass cover. These are commonly found affected with stem smut; often as much as 15-20 per cent of the plants are affected, and occasionally as 90 per cent infection is encountered. In view of these grasses as components of the western range, and the general interest manifest in the nature of the stem smuts so common on them, it seemed desirable to make a study of the identity of these smuts
