Plants annual; tufted or with solitary culms. Culms 3-60 cm, erect. Leaves mostly cauline; sheaths open, pubescent; auricles absent; ligules membranous; blades flat or involute, stiff. Inflorescences spikelike panicles, dense; branches scabrous to pubescent. Spikelets laterally compressed, with 2-7 florets; rachillas pubescent to almost glabrous, prolonged or not beyond the distal florets; disarticulation above the glumes and below the florets. Glumes unequal, membranous, glabrous or hirsute, keels ciliate; lower glumes shorter and narrower than the upper glumes, 1-veined; upper glumes subequal to the lowest lemmas, 3-veined; lemmas thin, membranous, glabrous or hirsute, margins shining and scarious, apices acute, awned from just below the bifid apices; paleas subequal to the lemmas, hyaline, veins sometimes extended into awnlike apices; anthers 3. Caryopses glabrous. x = 7. Name from the Latin rostrum, beak, and ari, having the nature of, a reference to the beaked lemma of the type species.