Setaria macrostachya H. B. K., plains bristlegrass 
DESCRIPTION 
Warm-season, perennial bunch grass. 
Height: 1 to 2-1/2 feet. 
Leaf blade: Flat to folded; upper surface rougher than 
lower. 
Leaf sheath: Open ; as long as or longer than internodes. 
Ligule: Hairy. 
Seedhead : Slender spikelike panicle 3 to 5 inches long; 2 to 
4 bristles below each pair of spikelets. 
GROWTH CHARACTERISTICS 
Grows from midspring until fall. Generally produces two seed 
crops, one in late spring, the other in early fall. This grass is a 
good seed producer because it has a high seedstalk to leaf ratio. 
Nodes are enlarged and close together near the base of the stem. 
Foliage is yellowish green, becoming straw colored at maturity. 
DISTRIBUTION 
South Texas to Oklahoma, eastern Colorado, and southern Kan- 
sas. 
SITE ADAPTATION 
Grows mostly on sandy to sandy loam soils. 
USE AND MANAGEMENT 
Plains bristlegrass is grazed by all livestock. It provides high- 
quality forage when green and succulent but becomes strawy 
after maturity. If grazed during dormant period, a mineral sup- 
plement should be provided. Birds eat the seed. This grass is used 
in seeding mixtures on some range sites in the Rio Grande plains. 
Plains bristlegrass decreases on ranges that are grazed contin- 
uously. To maintain vigor and produce a seed crop, grazing 
should be deferred every 2 to 3 years for 80 to 90 days before seed 
mature. 
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