Achnatherum robustumAchnatherum robustum, commonly known as sleepy grass, is a perennial plant in the Poaceae or grass family.DistributionIt grows on dry soil in the U.S. Midwest, ranging from South Dakota, Nebraska and Kansas, Wyoming, Colorado and New Mexico to Texas and Arizona, California and Hawaii.EcologySleepy grass plants harboring a fungal species, contain ergoline compounds, such as lysergic acid amide. These compounds appear to be responsible for the sedative effects on mammals when they ingest the infected grass.