In South Dakota it is called Wild Oats. Native. Perennial. Propagates by seeds. Time of bloom: June to July. Seed-time: July to August. Range: Prairies of the Middle Western States from Ohio to the

Rocky Mountains, north to Manitoba, British Columbia, and the Saskatchewan region. Habitat: Dry soil; wild meadows and pastures.

A large, stout grass, growing in tufts from a matted cluster of fibrous roots. Culms two to four feet tall, simple, erect, smooth. Sheaths long, mostly overlapping, slightly rough; basal blades about half as long as the culm, involute, and tapering to a thread-like point; stem leaves six inches to a foot long, hardly more than a sixth of an inch wide, generally flat but sometimes involute, with long, attenuate points. Panicles long and slim, with erect branches, the base at first often enclosed by the sheath but later much exserted. Spikelets one-seeded, the glumes smooth, very narrow and bristle-pointed, exceeding an inch in length; the lemma tightly enfolding the seed, hard, stiff, brown, its lower part clothed with short rigid hairs, and having a sharp-pointed beak or callus, and at the tip an awn, sometimes six inches long, rough, stiff, strongly twisted 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 sometimes 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.

Fig. 15.   Porcupine grass (Stipa spartea). X 1/5.

Fig. 15. - Porcupine-grass (Stipa spartea). X 1/5.

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.