HOW TO KNOW THE GRASSES 



16a. Spikelets when ripe disarticulating from the tip of the pedicel; end 

 of pedicel cup-shaped; rhizomes present; weed. Fig. 351. 



JOHNSON GRASS Sorghum haiepense (L.) Pers. 



Perennial; culms tall and stout, 0.5 — 

 2 m. tall, arising from thick, widely- 

 spreading rhizomes; panicle open, pyra- 

 mid-shaped, 15 — 50 cm. long. The ses- 

 sile spikelet is perfect and fertile, hard, 

 and rather plump, about 5 mm. long. 

 The awn falls off readily, so the spike- 

 lets are often awnless. The pedicellate 

 spikelets are of softer texture, staminate, 

 narrower, and awnless. The sessile 

 spikelet at the end of each short raceme 

 is accompanied by two pedicellate 

 spikelets. The fertile spikelets vary 

 from straw-colored to almost black. 

 This species, regarded as a noxious 

 weed in the southern states, is very 

 similar to the annual crop, Sudan grass. Despite its bad traits, John- 

 son grass furnishes a great deal of forage and is readily eaten by 

 Uvestock. Eurasian. 



16b. Spikelets when ripe breaking from the plant with the upper end 

 of the pedicel, leaving a jagged stub; rhizomes lacking; crop plant. 

 Fig. 352. 



SUDAN GRASS Sorghum sudanense (Piper) Stapf 



Figure 351 



Annual; tufted; culms 1 — 3 m. tall. The 

 plants resemble those of Johnson grass but 

 lack the rhizomes. Widely cultivated for 

 annual pasture and hay and sometimes 

 found as a stray from dropped seed. Native 

 to North Africa. 



Sorghum vulgare Pers. (SORGHUM) This 

 species includes a large group of rather corn- 

 like plants, cuhivated in warm sections of the 

 country for grain, fodder, silage, and syrup. 

 The leaves and stems greatly resemble Indian 

 com, but the spikelets, similar to those of 

 Johnson grass, are all borne in panicles at 

 the tips of the stems. The grains may be 

 black, brown, reddish, gray, or white. In 

 many varieties, the grain becomes large 

 enough to burst out of the glumes. Milo, hegari, feterita, durra, kafir 

 com, shallu, amber cane, broomcorn, etc. are all varieties of this spe- 

 cies. Broomcom is not used for forage, but the stiff, elongated panicle 

 branches are the broomstraw of commerce. 



Figure 352 



183 



