Description: This native grass is a summer annual about 1½–4' tall. Multiple culms are usually produced from the base that are sprawling, ascending, or erect. Each culm is green, glabrous, and terete; it is mostly hidden by the sheaths of the alternate leaves. The leaf blades are up to 1½' long and 1" across, although they are usually smaller in size. Each leaf blade is light to medium green, narrowly lanceolate, and hairless on both sides. The sheath of each leaf is light green to medium green, terete to somewhat flattened, and usually hairless; sometimes the upper portion of the sheath is slightly pubescent. The ligules are undeveloped, while the nodes of the culms are slightly swollen and often reddish.
Each culm terminates in a panicle of floral racemes up to 8" long and about half as much across; the central stalk of the panicle is light green, angular, and barely exerted from the uppermost leaf at its base. The floral racemes alternate on either side of the central stalk; they are slightly curved inward and become smaller as they ascend the stalk. Each raceme has dense clusters of spikelets along one side (usually facing upward or outward); these spikelets are green and ovoid in shape. Each spikelet consists of 2 glumes, 2 lemmas, and a floret. The first glume is about 1 mm. and broadly ovate, while the second glume and sterile outer lemma are about 3 mm. long and ovate. Both the second glume and sterile lemma are appressed together, hiding the fertile lemma and its floret. The outer surfaces of the second glume and sterile lemma have several longitudinal nerves that are slender and dark green; each nerve has a row of bristly hairs, while the surface between the nerves is light green and hairless to slightly pubescent. In this variety of Barnyard Grass, the tips of the second glume and sterile lemma are slender and pointed; sometimes the sterile lemma has an awn up to 3 mm. long. Each floret has a pair of pale purple plumose stigmas and 3 stamens. The blooming period can occur from mid-summer into the fall. Each spikelet produces a single grain. This grain is about 2.5 mm. long, ovoid, rather flattened, and tapering to a point at both ends. The root system is fibrous. This grass spreads by reseeding itself. At favorable sites, it can form substantial colonies.