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, 2.5 - 4 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, to 0.7 mm long. Stigmas red. Glumes:: Lower glumes 1 - 1.5 mm long, membranous. Upper glumes about equal to spikelets, 2.5 - 3.5 mm long, membranous. Lemmas:: Lower lemmas similar to upper glumes in texture and size, sometimes bristle-tipped (bristle to 1.5 mm 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. Microstachya means small-spiked.