Annuals, Terrestrial, not aquatic, Stems nodes swollen or brittle, Stems erect or ascending, Stems geniculate, decumbent, or lax, sometimes rooting at nodes, Stems caespitose, tufted, or clustered, Stems terete, round in cross section, or polygonal, Stem nodes bearded or hairy, Stem internodes ho llow, Stems with inflorescence less than 1 m tall, Stems, culms, or scapes exceeding basal leaves, Leaves mostly cauline, Leaves conspicuously 2-ranked, distichous, Leaves sheathing at base, Leaf sheath mostly open, or loose, Leaf sheath smooth, glabrous, Leaf sheath hairy at summit, throat, or collar, Leaf sheath and blade differentiated, Leaf blades linear, Leaf blades 2-10 mm wide, Leaf blades 1-2 cm wide, Leaf blades mostly flat, Leaf blades mostly glabrous, Leaf blades more or less hairy, Leaf blades scabrous, roughened, or wrinkled, Ligule present, Ligule an unfringed eciliate membrane, Inflorescence terminal, Inflorescence an open panicle, openly paniculate, branches spreading, Inflorescence a contracted panicle, narrowly paniculate, branches appressed or ascending, Inflorescence solitary, with 1 spike, fascicle, glomerule, head, or cluster per stem or culm, Inflorescence lax, widely spreading, branches drooping, pendulous, Inflorescence curved, twisted or nodding, Inflorescence branches more than 10 to numerous, Flowers bisexual, Spikelets pedicellate, Spikelets dorsally compressed or terete, Spikelet less than 3 mm wide, Spikelets with 1 fertile floret, Spikelets with 2 florets, Spikelet with 1 fertile floret and 1-2 sterile florets, Spikelets solitary at rachis nodes, Spikelets all alike and fertille, Spikelets bisexual, Spikelets disarticulating below the glumes, Rachilla or pedicel glabrous, Glumes present, empty bracts, Glumes 2 clearly present, Glumes distinctly unequal, Glumes equal to or longer than adjacent lemma, Glume equal to or longer than spikelet, Glumes 4-7 nerved, Glumes 8-15 nerved, Lemma similar in texture to glumes, Lemma 8-15 nerved, Lemma glabrous, Lemma apex truncate, rounded, or obtuse, Lemma awnless, Lemma margins inrolled, tightly covering palea and caryopsis, Lemma straight, Palea present, well developed, Palea about equal to lemma, Stamens 3, Styles 2-fid, deeply 2-branched, Stigmas 2, Fruit - caryopsis, Ca ryopsis ellipsoid, longitudinally grooved, hilum long-linear.
Stout annual 2-6(-10) dm; sheaths overlapping, densely hirsute; blades elongate, rounded at base, 10-20 mm wide; panicle included at base, pyramidal to cylindric, dense, 8-20 cm, often nodding at maturity; spikelets turgid, acute, 4.5-6 mm; first glume half as long, acute or acuminate, 5-veined; second glume and sterile lemma equal, distinctly 7- or 9- veined; fr stramineous to brown, 3-3.5 mm; 2n=36, 54, 72. Native of the Old World, occasionally cult. for forage and adventive along roadsides and in waste places. A wild-adapted type, widespread as a field-weed in the midwest (Wis., Minn., Ill., Io., N.D., S.D., Nebr., Kans., Colo.), has been named ssp. ruderale (Kit.) Tzvelev. It is larger, 7-20 dm, with open panicles 10-50 cm, and deciduous spikelets.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.