216 POACE^. 



the lower half, smooth above, except a short thin row of hairs, the 

 callus hard, acuminate, awn 9-17 cm. long, usually with two bends 

 near the middle, about 2 cm, distant. 



Illinois, Clark 1909 from Bebb, Beal 41 ; Iowa, TJ. S. Dept. 

 Agricul. 282, from /. C. Arthur ; British Columbia, Macoun. 



The long awns when alternately wet and dried bore their way 

 for several inches into the sand. They may also penetrate the flesh 

 of sheep and dogs, causing much annoyance and even death. 



Sandy oak-land or prairies ; Michigan, Illinois, to California. 



5. S. comata Trin. & Rupr. Mem. Acad. St. Petersb. (VI.) 5: 75 

 (1842). Bunch-grass. 



A rather stout and usually scabrous grass, 30-120 cm. high. 

 Sheaths mostly shorter than the internodes; ligule acute, 3-4-6 

 mm. long; leaves of sterile shoots a fourth to half the length of the 

 culm, those of the culm 2-5 in number. Panicle partially iiicluded, 

 open, 20-30 cm. long, rays distant in twos or threes, few-flowered. 

 Empty glumes nearly equal, 5-nerved, 20-30 mm. long including 

 the long slender point; floret pubescent with no crown of hairs at 

 the apex, 10-13 mm. long including a long sharp callus, awn ob- 

 scurely twice bent below, and variously curled and twisted above, 

 10-15 cm. long, sparsely pubescent to the second bend, shining 

 above or minutely pubescent; palea as long as its glume. Sta- 

 mens 3. 



Colorado, U. S. Dept. Agricul. 268; Oregon, Iloicell; Montana, 

 Atiderson. 



Found along the Rocky Mountains, furnishing considerable 

 pasture. 



6. S. mucronata H. B. K. Nov. Gen. et Sp. 1 : 125 (1815). 



A tufted erect perennial, 40-60 cm. high. Leaves of sterile 

 shoots numerous, ligule a ring with very short hairs; blades con- 

 duplicate, 5-10 cm. long, 0.6 mm. diam., those of the culm 2 in 

 number; upper ligule oblique, adherent, very short; blades 3-6 

 cm. long. Panicle exserted, simple, narrow, interrupted, 8-12 

 «m. long, rays in twos to fours, the longest 3-4 cm. long, bearing 

 3-4 spikelets on the outer half. Spikelets purplish brown, empty 

 <ylumes chartaceous, linear-acute, subequal, 5-G mm. long, 3-nerved, 



