Green foxtail – Setaria viridis
Setaria viridis (L.) Beauv.
Poaceae (Grass family)
Erect summer annual.
Leaves are hairless, rough, rolled in the bud and up to 12 inches long. Leaf sheaths are hairless except for short hairs along the margin.
Erect, mostly 3-foot-tall stems are branched and clump-forming at the base. Stems are usually round but are occasionally flattened in cross-section.
Flowers and fruit
The seedhead is a dense, cylinder-shaped, foxtail-like panicle with green to purple bristles. Usually erect to slightly nodding seedheads are capable of producing prolific amounts of oval to egg-shaped, yellowish brown seeds.
Giant foxtail (S. faberi Herrm.)
Differs by having a larger, up to 7-foot-tall stature, leaves with numerous short hairs on the upper surface, and longer, highly nodding panicles.
Yellow foxtail [S. glauca (L.) Beauv.]
Differs by having long, wispy hairs on the upper leaf surface near the stem, a panicle with yellowish-brown bristles, and a yellow to light brown seedhead at maturity.