374 FIELD CROPS FOR THE COTTON-BELT 



II. Pith dry. 



A. Panicle lax, 2.5-7 dm. long; peduncles erect; spikelets elliptic- 



oval or obovate, 2.5-3.5 mm. wide; lemmas awned. 



1. Panicle 4-7^ dm. long; rachis less than one-fifth as long as 



the panicle. 



a. Panicle umbelliform, the branches greatly elongated, 

 the tips drooping; seeds reddish, included. 



III. Broom-corn. 



2. Panicle 2.5-4 dm. long; rachis more than two-thirds as long 



as the panicle. 



a. Panicle conical, the branches strongly drooping; glumes 



at maturity spreading and involute; seeds white or 

 somewhat buff. IV. Shallu. 



b. Panicle oval or obovate, the branches spreading; 



glumes at maturity appressed, not involute; seeds 

 white, brown, or reddish. V. Kowliang. 



B. Panicle compact, 1-2.5 dm. long; peduncles erect or recurved; 



rachis more than two-thirds as long as the panicle. 



1. Spikelets elliptic-oval or obovate, 2.5-3.5 mm. wide; 



lemmas awned. V. Kowliang. 



2. Spikelets broadly obovate, 4.5-6 mm. wide. 



a. Glumes gray or greenish, not wrinkled; densely pubes- 



cent; lemmas awned or awnless; seeds strongly 

 flattened. VI. Durra. 



b. Glumes deep brown or black, transversely wrinkled; 



thinly pubescent; lemmas awned; seeds slightly 

 flattened. VII. Milo. 



The above classification does not include the grass sor- 

 ghums. Of the seven groups included in the above clas- 

 sification, sorgo has been developed primarily for its sugar 

 which is largely used in the form of sirup; kafir, milo, 

 shallu, kowliang, and durra have been developed pri- 

 marily as grain crops; and broom-corn for the " brush" 

 furnished by the seed-bearing branches of the panicle. 



462. Root-system. Careful studies of the root- 

 systems of sorghum and corn growing under the same con- 



