IDENTIFICATION" OF GRASSES. 13 



10. Annual bluegrass (Poa annua; fig. 14). 



A low-growing, glabrous, tufted annual; leaves folded in the bud; collar 

 glabrous; auricles none; ligule medium long, acute, entire; sheaths com- 

 pressed, glabrous ; blades flat, short, linear, pale yellowish green, one-eighth 

 inch wide. 



This grass often heads out when but 1 inch high. Rootstocks are rare ; when present, 

 very short. In the South it makes considerable winter growth. Two white lines along 

 the midnerve may be noticed by holding a blade up to the light and examining with a lens. 



11. Canada bluegrass (Poa compressa; fig. 15). 



A glabrous, bluish green perennial with creeping rootstocks forming a 

 loose turf ; leaves folded in the bud ; collar light green ; auricles none ; ligule 

 membranous, entire, acute, medium long ; sheaths strongly compressed, often 

 tinged with red ; blades fiat, long, linear, the apex like the bow of a boat, 

 bluish green but with double light lines along the midnerve when viewed by 

 transmitted light; rootstocks about one-sixteenth inch in diameter, each 

 branch usually terminating in a single shoot. 



This grass has more of a bluish color and grows in looser turf than Kentucky bluegrass, 

 with which it is most likely to be confused. 



Fig. 16. — Kentucky bluegrass (Poa 

 pratensis) . 



Fig. 17. 



-Rough-stalked meadow grass 

 (Poa trivialis). 



12. Kentucky bluegrass (Poa pratensis; fig. 16). 



A dark-green perennial, creeping by rootstocks and forming a dense turf ; 

 leaves folded in the bud ; collar narrow, glabrous ; auricles none, ligule 

 membranous, very short, truncate, entire ; sheaths green, smooth, com- 

 pressed ; blade long, linear, less than one-eighth inch wide, the tip abrupt 

 pointed like the bow of a boat, dark green, but with two light lines along 

 the midnerve when viewed by transmitted light ; rootstocks slender, branch- 

 ing, producing tufts with several shoots. 



13. Hough-stalked meadow grass (Poa trivialis; fig. 17). 



A dark-green, glabrous perennial, creeping by stolons ; leaves folded in 

 the bud ; collar wide, glabrous ; auricles none ; ligule long, membranous, 

 toothed at apex ; sheaths compressed, closed, rough to the touch ; blades 



