Knotroot Foxtail [Setaria parviflora (Poir.) Kerguélen]: “A sly fox”

Roem. & Schult.), giant foxtail (Setaria faberi Herrm.), and green foxtail (Setaria viridis L. P. Beauv.), but this genus also contains a crop species of historical significance, including foxtail millet (Setaria italica L. P. Beauv.) (Dekker 2003). Inflorescences of both yellow and knotroot foxtail are a cylindrical densely flowered panicle 3.0 to 10.0 cm long and 0.5 to 2.9 cm wide, with purple or yellow bristles 1 to 15 mm in length (Figure 5) for knotroot foxtail (Barkworth et al. 2007; Bryson and DeFelice 2009) compared with a slightly longer panicle (3 to 15 cm) with shorter bristles 3 to 3.5 mm long on yellow foxtail. Physical and morphological similarities are not surprising in the Setaria genus because most of the weedy foxtail species have low genetic diversity within species, especially in areas outside of a species native range, but significant variability species and populations (Wang et al. 1995a). Use of 2,4-D in cereal crops after World War II caused a weed population shift that allowed for a Setaria invasion in the United States.