176 



TUB TRUE GRASSES. 



SUB-TRIBE D. Triticeae. 



Spikelets transverse (side against the rachis); empty glumes opposite; 

 starch-grains simple. 



282. (266) Agropyrum Gartn. (Elytrigla Desv.). Spikes 

 with the rachis articulate or continuous ; spikelets more 



or less compressed, 

 3-co -flowered, all fer- 

 tile ; empty glumes not 

 inflated, narrower than 

 the flowering glumes, 

 lanceolate or linear; 

 flowering glumes coria- 

 ceous, rounded on the 

 back or slightly keeled 

 above, 5-7-nerved, 

 awnless or awned, the 

 uppermost often 

 sterile ; grain com- 

 pressed on the back, 

 hairy at the apex, 

 slightly sulcate. 



Species thirty-two, 

 distributed throughout 

 all temperate countries. 



Sec. I. Agropyrum. 

 Perennials. Spikes 



FiG.92.-^ro W rumreen,(L.)Beauv. (After Usually long and nar- 

 Nees, Gen. derm., I. 80.) row ^fa terminal 



spikelets ; empty glumes not keeled, 3-5-nerved. A. 

 repens Beauv. (Triticum repens L.). "Couch grass," 

 "Witch grass" (Fig. 92), has creeping .rhizomes, flat 

 leaves, somewhat acute empty and flowering glumes. 

 Common in Europe and Asia, also in North and South 

 America. A troublesome weed in cultivated fields. The 

 somewhat superficial, creeping runners may be removed 

 by harrowing and raking them off, or killed by deep 

 ploughing ; and they may be smothered by thick plant- 

 ing of leafy plants, like the clover. For poor pastures it 

 is, especially when young, valuable fodder-grass and is 



