Introduced warm-season annual or short-lived perennial tufted or stolon-forming C4 grass to 120 cm tall. Nodes are dark coloured and the basal leaf sheaths are paler than the blades. Flowerheads are digitate, with 7-19 branches that are erect and 3-7 cm long. Spikelets are pale green when young, black at maturity, blunt at their apex and 2-flowered; lower floret is fertile and its lemma has hairy margins; upper floret is reduced to a lemma; awns are longer than the spikelet. Germinates in summer and flowers in autumn. A native of America, it is found in disturbed areas, such as roadsides, yards, creek banks and cultivated paddocks. Very sensitive to frost, fire and flooding. An indicator of disturbance or high fertility or both. A pioneer species which quickly occupies disturbed areas; it is a weed of roadsides, railways, disturbed sites and cropping. Tolerant of many herbicides used in roadside spraying and cropping (especially a problem for zero-till farming). Provides ground cover on shallow compacted soils where little else will grow. Moderately palatable when young but ignored as it matures; it is of little use for grazing because it has a short summer to early autumn growing season and only grows in disturbed areas with poor ground cover.