Plants annual; tufted or with solitary culms. Culms 3-60 cm, erect. Leaves mostly cauline; sheaths open, pubescent; auricles absent; ligulesmembranous; 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 glumessubequal 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.
Rostraria is a genus of approximately 10 species, all of which are native to the Mediterranean, southeastern Europe, and western Asia, where they grow in dry, disturbed sites. The genus is sometimes included in Koeleria; it differs in its annual growth habit and awned lemmas and paleas.