Setaria pumila is a species of grass known by many common names, including yellow foxtail, yellow bristle-grass, pigeon grass, and cattail grass. It is native to Europe, but it is known throughout the world as a common weed. It grows in lawns, sidewalks, roadsides, cultivated fields, and many other places. This annual grass grows 200NaN0 to well over 10NaN0 in height, its mostly hairless stems ranging from green to purple-tinged in color. The leaf blades are hairless on the upper surfaces, twisting, and up to 300NaN0 long. The inflorescence is a stiff, cylindrical bundle of spikelets NaNfrac=4NaNfrac=4 long with short, blunt bristles. The panicle may appear yellow or yellow-tinged.
In New Zealand S. pumila can cover 20–40% of otherwise productive dairy farming pasture causing a loss in milk production.[1]