HOW TO KNOW THE GRASSES 



15a. Lower sheaths glabrous; fertile floret ovoid, 1.9 — 2.2 times longer 

 than wide. Fig. 295. 



BARNYARD GRASS EchinocWoa pungens (Poir.) Rydb. 



Annual; tufted; plants robust, up to 1.5 

 m. tall, with panicles up to 20 cm. long, 

 with spreading branches. The spikelets 

 are covered with stout, spine-like hairs 

 which arise from little yellowish blisters. 

 Disturbed soil, in ditches, fields, marsh- 

 es, borders of ponds. August — Septem- 

 ber. 



Echinochioa crusgalli (L.) Beauv. is 

 similar but does not have the blister- 

 based stout spines on the spikelets. Just 

 below the withering tip of the fertile 

 lemma is a circle of minute hairs. These 

 are absent in the preceding species. 

 Fields and waste places; widespread; 

 supposedly introduced from Europe. 



Figure 295 



15b. Lower sheaths bristly with stiff hairs; fertUe floret elliptical, 2.5 

 — 3 times longer than wide. Fig. 296. 



Echinochoa walteri (Pursh) Nash 



Annual; tufted; robust, up to 2 m. tall; pani- 

 cles up to 30 cm. long. The spikelets usually 

 bear awns 1 — 2.5 cm. long. Individuals with 

 glabrous sheaths can be identified by the 

 narrow spikelets. Wet ground or shallow 

 water, sometimes in brackish areas, mostly 

 on the Atlantic and Gulf Coastal Plains. Au- 

 gust — September. 



Figure 296 



16a. Spikelets borne in 1 — 4 rows along the lower sides of one or more 

 slender, spikelike racemes 17 



16b. Spikelets borne in open or dense panicles, not exclusively on the 

 lower sides of branches 28 



156 



