166 



Fig. 160. TRISETTJM STJBSPICATUM (Linn.) Beauv.AgrOst. 180. 1812. {Aira 

 suUpimta Linn. Syst. Nat. ed. 10, 073. 1759; Avcna mollis Michx. Fl. Bor. Am. 1 : 72. 

 1803.) DOWNY OAT-GRASS.— A slender, erect perennial 1.5-4.5 dm. (i°-li°) 

 high, Avith usually downy culms and leaves, and densely many-flowered, spike- 

 like panicles, 2..5-12 cm, (l'-5') long. Sheaths usually shorter than the internodes; 

 ligule 1-2 mm. (i"-l"^ long; leaf-blades 2-10 cm. (l'-4')long, 1-4 mm. W-2") 

 wide. Spikelets (a) 2-3-flowered, the larger second empty glume about 5 mm. 

 (2i") long: flowering glumes (6, c) 4-5 mm. (2"-2i") long, awned, the awns bent 

 and twisted at least when dry.— Widely distributed in the cooler temperate 

 regions of both hemispheres, ranging in North America from Labrador to 

 Alaska and extending .southward in the Eastern States to the mountains of 

 North Carolina and Tennessee, and in the West to New Mexico and California. 

 (Europe, Asia.) June to September. 



