During the last decade, there has been much interest manifested in regard to plants injurious to live stock. Numerous contributions have been made along this line, notably by Dr. Chesnut, formerly of the United States Department of Agriculture, Drs. True and Wilcox and their co-workers also of Washington, Dr. Schaffner of the Ohio State University, Dr. Jones of the Vermont Agriculture Experiment Station, Dr. Kennedy of the Nevada Experiment Station, Dr. Nelson of the Wyoming Station, Dr. Nelson of Washington, and Drs. Peters and Bessey of Nebraska. Other station botanists have also contributed to the same line of work. Much of the literature is scattered, however, hence an effort has been made to bring together in the following pages the results obtained.