About Setaria pumila (Poir.) Roem. & Schult.
Setaria pumila (Poir.) Roem. & Schult. is a grass species with many common names: yellow foxtail, yellow bristle-grass, pigeon grass, and cattail grass. It is native to Europe, but is now a widespread common weed across the globe. It grows in lawns, along sidewalks and roadsides, in cultivated fields, and many other locations. This annual grass reaches heights from 20 centimeters (8 inches) to well over 1 meter (1 yard). Its mostly hairless stems range in color from green to purple-tinged. The hairless upper surfaces of its leaf blades are twisted, and can grow up to 30 centimeters (12 inches) long. Its inflorescence is a stiff, cylindrical cluster of spikelets that is 2 to 15 centimeters (3⁄4 to 6 inches) long, marked with short, blunt bristles. The panicle often appears yellow or yellow-tinged. In New Zealand, S. pumila can cover 20–40% of otherwise productive dairy pasture, leading to reduced milk production.
