1. Bristles, summit of culm, and axis of panicle scabrous with retrorse barbs; panicle branches tending to appear whorled, the panicle ± interrupted toward its base.

S. verticillata

1. Bristles, summit of culm, and axis of panicle scabrous or pubescent with antrorse barbs or hairs; panicle very compact throughout.

2. Fertile lemmas mostly ca. (2.7–) 3 (–3.4) mm long, rugose with distinctly transverse ridges, the upper half exposed at maturity; bristles 5 or more per spikelet, becoming orange or golden-brown; sheaths glabrous.

S. pumila

2. Fertile lemmas less than 3 mm long, evenly and finely rugose or reticulate or smooth (without transverse ridges), the upper half largely or entirely concealed at maturity; bristles fewer than 5 per spikelet, pale greenish or purple (rarely yellow) at maturity; sheaths ciliate with long hairs on the margins.

3. Spikelet articulated above the glumes and sterile lemma; fertile lemma distinctly yellow or darker at maturity; panicle very dense, often ± lobed in appearance.

S. italica

3. Spikelet articulated below the glumes; fertile lemma pale green or brown; panicle not lobed.

4. Panicle strongly nodding, bent below the middle; spikelets mostly over 2.5 mm long, the fertile lemma ± tapering to a distinctly exposed tip; leaf blades ± hairy above.

S. faberi

4. Panicle straight and erect or rarely slightly nodding; spikelets not over 2.5 mm long, the blunt fertile lemma nearly or quite concealed by the second glume; leaf blades glabrous above.

S. viridis

All species found in Setaria

Setaria faberiGIANT FOXTAIL 
Setaria pumilaYELLOW FOXTAIL 
Setaria verticillataBRISTLY FOXTAIL 
Setaria viridisGREEN FOXTAIL 


MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. March 18, 2018.