Knotroot Foxtail
Scientific Name - Setaria geniculata (Lam.) Beauv.
Family - Gramineae
preading perennial from short knotty rhizomes. Leaves smooth, occasionally hairy at the base of blade. Leaf sheath smooth. Seedhead a dense spike resembling a fox's tail, yellow to purple. Spikelets surrounded by four to twelve bristles. Reproduces by seed. Found throughout the United States. Also occurs in the West Indies, Mexico, Central and South America, Hawaii and Europe. Yellow foxtail [Setaria glauca (L.) Beauv.] is similar but lacks short rhizomes. Green foxtail [Setaria viridis (L.) Beauv.] is also similar, but lacks short rhizomes, has hairs at the top of the leaf sheath, and has zero to three bristles per spikelet.