Setaria geniculata (Lam.). Knotroot Bristlegrass Habit: Perennial, producing short knotty branching rhizomes as much as 4 cm. long, resembling Setaria lutescens. Culms: 30-80 cm. tall, often tufted, slender, wiry. Blades: Erect, 15 cm. long or less, 5-7 mm. wide or less, mainly straight (not twisted), long acuminate, glabrous. Sheaths: Shorter than the internodes, flattened, keeled, glabrous. Ligule: Membranous, short, ciliate. Inflorescence: A dense terminal cylindric spikelike panicle, 3-5 cm. long, 1 cm. thick, green, yellowish or purple, the axis densely pubescent, with about 6 bristles below each spikelet, sometimes many more, as long as to several times the length of spikelet, usually 2-3- times as long, upwardly barbed. Spikelets: 2-2.5 to 3 mm. long, plano-convex, ovoid. Glumes: First about one third as long as the spikelet, 3-nerved, second about two thirds as long, 5-nerved. Sterile lemma frequently longer than the second glume, 5-7-nerved, empty, or rarely enclosing a palea and also sometimes a staminate flower. Fertile lemmas: Leathery-indurate, enclosing a shorter palea, strongly transversely rugose. Fruit: Subacute, about qual to the sterile lemma, finely transversely-undulate, rugose. Habitat: Meadows, salt marshes, and cultivated ground. July-September. Kansas Range: Scattered in south two thirds. Synonyms: Setaria geniculata auct. non (Wild.) Beauv. Setaria gracilis Kunth