Annuals or perennials, tufted, or widely creeping and rhizomatous or stoloniferous. Leaf-sheath rounded. Ligule membranous. Leaf-blade flat or involute. Culm of various height, erect, or decumbent and geniculately ascending; nodes glabrous. Inflorescence a diffuse and often delicately branched or contracted panicle, sometimes spike-like, rarely much reduced and hidden among leaves; rachis persistent at maturity. Spikelets small, numerous to few, 1-flowered; disarticulation above glumes; rachilla usually not prolonged. Glumes equal to subequal, lanceolate, acute to acuminate, sometimes subobtuse, membranous, shining, 1-nerved, keel ± scabrid. Lemma usually < glumes, thinner in texture than glumes, hyaline to firmly membranous, broadly ovate, usually truncate to dentate, rounded, 3-5-(7)-nerved with nerves sometimes excurrent, awnless or with a dorsal awn. Palea hyaline, 2-keeled or nerveless, usually < lemma, sometimes very small or obsolete, almost covered by inrolled margins of lemma. Callus short or minute, blunt, glabrous, or with ± minute lateral tufts of hairs. Lodicules 2, lanceolate, hyaline. Stamens 3. Ovary glabrous; styles distinct, free to base, short; stigmas 2, plumose. Caryopsis ovoid or fusiform, ± dorsally compressed, longitudinally grooved or rarely terete; embryo small; hilum punctiform or elongate; endosperm sometimes liquid. Chasmogamous (N.Z. spp.).

Annual or perennial, tufted, or widely creeping and rhizomatous or stoloniferous. Sheaths rounded at back; ligule membranous; lamina flat or involute. Culms of various height, erect, or decumbent and geniculately ascending; nodes glabrous. Inflorescence a diffuse and often delicately branched or contracted panicle, sometimes spike-like, rarely much reduced and hidden among leaves; panicle rachis persistent at maturity. Spikelets small, numerous to few, 1-flowered, hermaphrodite; rachilla disarticulating above glumes, usually not prolonged. Glumes equal to subequal, lanceolate, acute to acuminate, sometimes subobtuse, membranous, shining, 1-nerved, keel ± scabrous. Lemma usually < glumes, thinner in texture than glumes, hyaline to firmly membranous, broadly ovate, usually truncate to dentate, rounded at back, 3-5-(7)- nerved, with nerves sometimes excurrent, awnless or with a dorsal awn. Palea hyaline, 2-keeled or nerveless, usually < lemma, sometimes very small or obsolete, almost covered by inrolled margins of lemma. Callus short or minute, blunt, glabrous, or with ± minute lateral tufts of hairs. Lodicules 2, lanceolate, hyaline, Stamens 3. Ovary glabrous; styles distinct, free to base, short; stigmas 2, plumose. Caryopsis ovoid or fusiform, ± dorsally compressed, longitudinally grooved or terete; embryo small; hilum punctiform or elongate; endosperm sometimes liquid. Flowering in all indigenous species is chasmogamous. Temperate regions throughout the world and in the tropics at high altitudes, c. 220 species.