Comparison of foxtails (Setaria spp.):

  life cycle bristles per spikelet* direction of bristle barbs spike aspect & L x W (includes bristles) blade upper surface sheath margins

yellow foxtail

S. pumila

annual 4-15 point forward

erect to slightly lax

2-8 x 1-2 cm

glabrous, base w/ long hairs glabrous

green foxtail

S. viridis

annual 1-4** point forward

erect to slightly lax

2-15 x 1-2 cm

glabrous ciliate

giant foxtail

S. faberi

annual (1)2-3 point forward

drooping

7-18 x 1.5-3 cm

sparsely short-hairy ciliate

bristly foxtail

S. verticillata

annual 1-2(3) point backwards

erect to slightly lax

3-15 x 0.5-1 cm

glabrous or sparsely short-hairy glabrous or sparsely ciliate

knotroot foxtail

S. gracilis

perennial w/ short, knotty rhizomes 4-12 point forward

erect

3-9 x 0.4-1 cm

glabrous glabrous

African bristlegrass

S. sphacelata

perennial w/ short rhizomes 5-15 point forward

erect

9-40 x 0.8-1.5 cm

glabrous, (base w/ few long hairs) glabrous

* Easiest to see when spikelets have fallen or been carefully removed.

**Spikelets closely clustered; bristles may appear more numerous, especially when spikelets abort.