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Setaria
See list of 6 species in this genusReference: Rominger (2003).
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1a. Plants perennial from short, knotty rhizomes; axis of inflorescence scabrous-hispid
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1b. Plants annual from fibrous roots; axis of the inflorescence villous and/or hispid or scabrous-hispid in S. verticillata
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2a. Each spikelet subtended by 4–12 bristles [Fig. 269]; spikelets 3–3.5 mm long
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2b. Each spikelet subtended by 1–3 bristles (up to 6 in S. faberi); spikelets 1.6–3 mm long
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3a. Axis of the panicle retrorsely scabrous-hispid; branches of the panicle verticillate; inflorescence 5–12 mm thick; leaf blades usually spreading; bristles of the inflorescence retrorsely scabrous
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3b. Axis of the panicle villous to hispid, but not scabrous; branches of the panicle not verticillate; inflorescence 7–35 mm thick; leaf blades usually ascending (at least the basal portion of the blade); bristles of the inflorescence antrorsely scabrous
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4a. Fertile lemma smooth (rarely very finely transerve rugose), lustrous; disarticulation above the glumes, the caryopsis falling free from the more persistent glumes; mature caryopsis yellow to red or brown to black
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4b. Fertile lemma evidently transversely rugulose, dull; disarticulation below the glumes, the entire spikelet, including the caryopsis, falling intact; mature caryopsis green
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5a. Leaves pubescent with soft hairs and scabrous on the adaxial surface; spikelets 2.5–3 mm long; inflorescence nodding from near the base [Fig. 268], 20–30 mm wide; second glume 65–75% as long as the spikelet
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5b. Leaves scabrous on the adaxial surface; spikelets 1.8–2.2 mm long; inflorescence erect or nodding from near the apex [Fig. 270], 10–23 mm wide; second glume nearly as long as the spikelet
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Each photo represents one species in this genus.