Panicum

Panicum is a genus of grasses, family Poaceae, comprising approximately 250 species, native throughout the tropical regions of the world with a few species extending into the northern temperate zone; Australia alone hosts 29 native and 9 introduced varieties. Plants are typically large annual or perennial grasses growing one to three meters tall, producing flowers in well developed panicles reaching up to 60 centimeters in length, with two-flowered spikelets in which only the upper floret is fertile and seeds one to six millimeters long. Well known species include Panicum miliaceum, proso millet, a domesticated cereal; Panicum virgatum, switchgrass, a North American species used for biomass production; and Panicum capillare, witchgrass, also called tumbleweed. Recent phylogenetic research found the genus as previously circumscribed to be polyphyletic, leading to reclassification of some former member species into other genera.