Panicum is a large genus of about 450 species of grasses native throughout the tropical regions of the world, with a few species extending into the northern temperate zone. They are often large, annual or perennial grasses, growing to 1–3 m tall.The flowers are produced in a well-developed panicle often up to 60 cm in length with numerous seeds, which are 1–6 mm long and 1–2 mm broad. The fruits are developed from a two-flowered spikelet. Only the upper floret of each spikelet is fertile; the lower floret is sterile or staminate. Both glumes are present and well developed.Australia has 29 native and 9 introduced species of Panicum.Well-known Panicum species include proso millet and switchgrass.