HOW TO KNOW THE GRASSES 



28b. Second glume sack-like, swollen, the spikelet hence "lop-sided"; 

 fertile floret about half as long as the sterile lemma. Fig. 311. 

 SACK GRASS Sacciolepis striata (L.) Nash 



Perennial; culms often decumbent and 

 rooting at the lower nodes, up to 2 m. long. 

 The leaf sheaths may be bristly-hairy or 

 smooth. Panicles dense, cylindrical, 6 — 

 30 cm. long. The spikelets are flat on the 

 first glume side, very bulging at the base 

 on the second glimie side. Ditches, marsh- 

 es and swamps, on the Atlantic and Gulf 

 Coastal Plains. June — December. 



Figure 31 1 



29a. First glume absent or minute, less than 1/10 as long as the spike- 

 let 30 



29b. First glume present, usually at least 1/4 as long as the spikelet. 31 



30a. Spikelets hairy, 2 — 3 mm. long; no underground spikelets present. 

 Fig. 312. 



FALL WITCHGRASS Leptoloma cognatum (Schult.) Chase 



Perennial; plants stiffly spreading or 

 erect, in large tufts; culms 30 — 70 cm. long; 

 panicles very open, with stiffly spreading, 

 thin, somewhat zig-zag branches. The pedi- 

 cels of the individual spikelets may be 

 up to 20 — 30 times the length of the spike- 

 let. The second glume and sterile lemma 

 bear oppressed hairs. When mature, the 

 panicles break off and roll away as tumble- 

 weeds. Dry sandy open soil. May — Sep- 

 tember. 



Figure 312 



163 



