Annual herb 0.8 - 1.5 m tall Leaves: alternate, two-ranked. Sheaths open, compressed. Ligules absent. Blades 1 - 27 cm long, 0.5 mm - 3 cm wide, usually over ten times longer than wide, linear to lance-shaped, flat, parallel-veined, with a prominent midrib. Inflorescence: a terminal arrangement of spikelets (panicle), to 35 cm long, with an elongate and sometimes hairy axis. Primary branches spreading, distant, 2 - 8 cm long, often bearing secondary branches. Fruit: a caryopsis, indehiscent, enclosed within the persistent lemma and palea, yellowish, 1 - 2.5 mm long, broadly egg-shaped to spherical. Culm: upright or spreading, 0.8 - 1.5 m long, round in cross-section, sometimes rooting at the lower nodes, often developing short axillary shoots at the upper nodes when mature. Lower nodes sometimes minutely hairy. Spikelets: densely crowded on angular branches, purple or purple-streaked, 3.5 - 5 mm long, flat on one side and convex on the other (plano-convex), with bumpy-based hairs. Florets: two per spikelet. Lower florets sterile. Upper florets bisexual, compressed dorsally. Anthers three, 0.5 - 1 mm long. Stigmas red. Glumes:: Lower glumes 1 - 2.5 mm long, membranous. Upper glumes about equal to spikelets, 3 - 5 mm long, membranous. Lemmas:: Lower lemmas similar to upper glumes in texture and size, usually bristle-tipped (bristle to 1.5 cm long). Upper lemmas broadly reverse egg-shaped or circular with a leather-like, narrowing apex (tip membranous), rounded dorsally, leather-like. Paleas:: Lower paleas well-developed.
Similar species: No information at this time.
Flowering: August to October
Habitat and ecology: Disturbed areas, often in moist soil.
Occurence in the Chicago region: native
Etymology: Echinochloa comes from the Greek words echinos, meaning hedgehog, and chloa, meaning grass, referring to the bristly spikelets of some species. Muricata means roughened.
Spikelets 3.5 mm or more to the base of the awn or mucronate tip of the sterile lemma; sterile lemma with an awn 6-25 mm, or seldom awnless. (E. pungens)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.