HOW TO KNOW THE GRASSES 



105a. Culms round or nearly so in cross section (in pressed specimens, 

 at least the nodes will be round) 106 



105b. Culms strongly flattened, lens-shaped in cross section; spikelets 

 never woolly. Fig. 142. 



CANADA BLUEGRASS Poa compressa L. 



Perennial; rhizome-bearing; panicles nar- 

 row, 3 — 7 cm. long. The plants are rather 

 wiry and form looser turf than Kentucky 

 bluegrass. It is somewhat more drought 

 resistant than the former species, but yields 

 less forage. The plants bloom several 

 weeks later than Kentucky bluegrass in 

 the same locality. Mid-May — September. 

 Introduced from Europe. 



Figure 142 



106a. Lemmas completely glabrous or minutely scabrous, 

 or with a small web of cottony hairs (Fig. 143) at- 

 tached to the callus 107 



106b. Lemmas pubescent on the keel or nerves, some- 

 times with a web at the base also 108 



Figure 143 



107a. Panicles dense, with short branches, the spikelets overlapping; 

 southern plains states or Southeast 1 10b 



107b. Panicles open, the slender spreading branches naked at the base; 

 western mountains 109b 



108a. Lemmas pubescent only on the nerves; glabrous between them 



109 



75 



