Yellow Foxtail or Setaria pratense

"Setaria verticillata" is a species of grass. It is native to Europe, but it is known on most continents as an introduced species and often a noxious weed. It is a hardy bunchgrass which grows in many types of urban, cultivated, and disturbed habitat. It is a weed of many types of agricultural crops, growing in vineyards and fields. Herbicide-resistant strains have been noted.