40 GRAMINEAE (GRASS FAMILY) 
for half its length, usually with a double bend beyond the straight 
spiral. (Fig. 15.) This spiral awn relaxes when damp and 
tightens again when dry, enabling the seed to bore its way 
into the soil with the sharp beak at its base; but if caught in 
the wool of a sheep it bores just as readily into the flesh of the 
animal, the stiff hairs near the base of the seed holding it in place 
while the awn twists and untwists through days of torment, 
making sores which injure the quality of the wool and some- 
times endanger the creature’s life. Hay containing the awns is 
worse than worthless, for, when eaten by horses, cattle, or sheep, 
the broken bits*lodge in the intestines, causing inflammation so 
serious as sometimes to end in death. 
Means of control 
Mowing so frequently or grazing so closely as entirely to prevent 
the formation of seed. If the grass is very abundant, the land 
should be broken up and put to a soiling crop before reseeding. 
WESTERN STIPA 
Siipa comdta, Trin. & Rupr. 
Other English names: Needle-grass, Needle-and-thread. 
Native. Perennial. Propagates by seed. 
Time of bloom: June to July. 
Seed-time: July to August. 
Range: Plains of the Missouri River, the Rocky Mountain foothills 
of Northwest Canada, and in New Mexico and California. 
Habitat: Dry soil; wild meadows and pastures. 
A close relative of the preceding species but not quite so vicious. 
Both these grasses make excellent forage when young, and good 
hay when cut before seed development; but there are grasses, as 
good as these or better, that do not carry such offensive weapons. 
Culms erect, smooth, simple, one to two feet tall, growing in 
thick tufts or mats. Sheaths overlapping, mostly crowded at the 
base, the upper ones long and loose and often enclosing the lower 
part of the panicle; basal blades about half as long as the culm, 
involute, with very long, thread-like tip; stem leaves three to six 
inches long, broader than the basal ones, involute. Panicle erect, 
six to ten inches long, somewhat loose and spreading; spikelets 
