Setaria parviflora is a species of grass known by the common names marsh bristlegrass,[2] knotroot bristle-grass,[3] bristly foxtail and yellow bristlegrass.

[5] This grass is a perennial with small, knotty rhizomes.

[6] The inflorescence is a compact, spikelike panicle up to 8 or 10 centimeters long.

[4] The bristles stay on the stalk after the seeds drop away.

[4] It can grow in salty habitat such as salt marshes.