246 BULLETIN 772, U. S. DEPARTMENT OF AGRICULTURE. 



Penicillaria Willd., Enum. PL 2: 1036. 1809. A single species, p. spicatus, 

 based on Holcus sjncatus L., is described. 



Gymnothrix Beauv., Ess. Agrost. 59, pi. 13. f. 6. 1812. The type species is 

 G. thourii, the one figured. Beauvois distinguished Gymnothrix from Pen- 

 niseturn by the glabrous (not plumose) bristles. 



The most important species of the genus is Pennisetum 

 glaucum (L.) R. Br. (P. typkoideumRich., P. ameri- 

 canum (L.) Schum., Penicillaria spicata (L.) Willd.), 

 called in this country pearl millet (fig. 149). This is a 

 robust annual, 4 to 8 feet tall, with broad blades like 

 those of corn or sorghum, and a dense, erect, cylindric 

 spikelike panicle as much as a foot long, the stem woolly 

 below the spike, the involucre containing usually two 

 spikelets about as long as the bristles. Pearl millet dif- 

 fers from the other Paniceae in having an enlarged cary- 

 opsis bursting through its lemma and palea. The cary- 

 opsis, or "seed," is deciduous by an articulation above 

 the fertile lemma, the bristles and the floral bracts re- 

 maining on the spike. Pearl millet is widely cultivated 

 in tropical Africa and Asia, the seed being used for hu- 

 man food. The species has been cultivated since pre- 



FIG. 149. Pearl millet, Pennisetum glaucum. Inflorescence, X \ ', two views of spikelet 



and caryopsis, X 10. 



historic times, its wild prototype being unknown. In the United 

 States pearl millet is used to a limited extent in the Southern States 

 for forage, especially for soiling. 



