Achnatherum robustum

Achnatherum robustum, commonly known as sleepy grass, (synonyms Stipa robusta, also Stipa vaseyi subsp. robusta) is a perennial plant in the Poaceae or grass family.

It 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 and Hawaii.

Sleepy grass plants harboring a fungal species (of the genus Neotyphodium), contain ergoline compounds, such as lysergic acid amide (common name, ergine). These compounds appear to be responsible for the sedative effects on mammals when they ingest the infected grass.