183 



Fig. 165. Avena americana (Scribn.) (A. pratcnsis var. ameri- 

 cana Scribn. ; A. hookeri Scribn.). American Oat. — A rigidly erect 

 perennial 3 to (5 dm. bigb, witb narrow, firm leaves, and con- 

 tracted panicles 8 to 12 cm. long. — Open tbickets and prairies, 

 Manitoba, and in tbe footbills of tbe Rocky Mountains south- 

 ward to Colorado. June-August. 



