HOW TO KNOW THE GRASSES 



50a. First glume rounded or broadly triangular, 1/4 — 1/3 as long as 

 the spikelet; plants annual, without rhizomes. Fig. 334. 

 FALL PANICUM Panicuzn dichotomifloTum Michx. 



Annual; tufted; plants bushy, with freely 

 branching erect or spreading culms; often 

 coarse, with culms up to 2 m. long in vigor- 

 ous specimens; stems often zig-zag, with an 

 axillary panicle at each upper node. This is 

 a common weed of cultivated fields, waste 

 ground and moist soil around ponds or along 

 streams. The size of the plants varies greatly, 

 depending upon the moisture and fertiUty of 

 the soil. July — October. 



Figure 334 



50b. First glume at least half the length of the spikelet, tapering to a 

 sharp point; plants perennial, with hard, rhizome-producing bases* 

 Fig. 335. 



SWITCH GRASS Panicum virgatum L. 



Perennial; in clumps, spreading by thick scaly 

 rhizomes; culms strong, 1 — 2 m. tall; panicles 

 large and open, 15 — 50 cm. long; spikelets 3.5 

 — 5 mm. long, often reddish in color and at 

 times appearing laterally compressed. Switch 

 grass is one of the most important native grasses 

 of the tall grass prairie, but occurs far beyond 

 the prairie area as well. Prairies, open ground, 

 river banks and bottomlands, thin woods. A 

 valuable forage species, sometimes harvested 

 as a part of wild prairie hay. July — October. 



Figure 335 



174 



