American barnyard grass

Echinochloa muricata, commonly known as American barnyard grass or rough barnyard grass, is a robust warm-season annual grass in the Poaceae native to wet ground, marsh edges, ditches, river flats and disturbed moist soils across most of temperate and warm North America. Plants form tufts 50 to 150 centimetres tall with stout, somewhat decumbent and rooting culms branching at the lower nodes. Leaf sheaths are glabrous and open, the ligule absent (a diagnostic feature of the genus), and the flat linear blades are 10 to 40 centimetres long and 5 to 25 millimetres wide with scabrous margins. The terminal inflorescence is a stiff, narrowly pyramidal panicle 8 to 25 centimetres long composed of several to many ascending to spreading branches densely set with crowded, sessile, ovoid spikelets 3 to 5 millimetres long; each spikelet is hispid with stout pustular-based bristles and bears a coarse straight to flexuous awn 5 to 25 millimetres long. The shining, hardened lemma encloses a single small grain. Echinochloa muricata is closely related to the cultivated Japanese millet.