THE SORGHUMS 373 



referred to above. This view has been expressed by- 

 Piper in his book on Forage Plants. 



460. Geographical origin. — The cultivated sorghums 

 originated in the tropics of the Old World. An independent 

 origin in tropical Africa and in India is held by Ball.^ 

 Hackel,^ as a result of his studies, concludes that the culti- 

 vated sorghums originated in Africa. As the wild annual 

 forms of sorghum are confined largely to Africa, the 

 African origin 6i the cultivated forms seems the most 

 likely. 



461. Botanical classification. — Botanically the sor- 

 ghums are classed as follows: Order — Gramineae; tribe — ■ 

 Andropogonese; genus — Andropogon; species — ^ Sorghum 

 var. vulgare. 



, As a key to^ the principal groups of sorghum, the follow- 

 ing classification has been proposed by Ball:^ 



I. Pith juicy. 



A. Juice abundant and very sweet. 



1. Internodes elongated; sheaths scarcely overlapping; 

 leaves 12-15 (except in Amber varieties); spikelets 

 elliptic-oval to obovate, 2.5-3.5 mm.' wide; seeds 

 reddish brown. I. Sorgo. 



B. Juice scanty, slightly sweet to subacid. 



1. Internodes short; sheaths strongly overlapping; leaves 



12-15; peduncles erect; panicles cylindrical; spikelets 

 obovate, 3-4 mm. wide; lemmas awnless. II. Kafir. 



2. Internodes medium; sheaths scarcely overlapping; leaves 



8-11; peduncles mostly inclined, often recurved; panicles 

 ovate; spikelets broadly obovate, 4.5-6 mm. wide; 

 lemmas awned. ' VII. Milq, 



' Ball, Carleton R., U. S. Dep't of Agr. Bur. Plant Ind., Bui. 176,~ 

 pp. 9-10. 



2 Hackel, Edward, "The True Grasses," p. 59. 



'Ball, Carleton R.,'U. S. Dep't Agr. Bur. Plant Ind., Bui. 175, 

 p. 8. 



