47 



POLYPOGON. 



Awn of glumes 2-3 lin. long P. monspeliensis. 



Awn of glumes up to 1 in. long. Side nerves of valve 

 excurrent into bristles P. tenuis. 



PRIONANTHIUM. 



Lateral nerves of the glumes close to the keels. Mem- 

 branous margins very broad P. rigidum. 



Lateral nerves of the glumes more equally distributed. 

 Margins narrow P. ecklonii. 



SCIIISMUS. 



1. Awn of valve 2-3 times the length of the lobes. Anthers 



h lin. long S. aristulatus. 



Valves without or with a mucro, not or slightly exceeding 

 the lobes. Anthers 1-4- lin. long 2 



2. Spikelets narrow. Glumes thin, acute, or acuminate. 



S. fasciculatus. 

 Spikelets slightly turgid. Glumes somewhat firm, sub- 

 obtuse S. koelerioides. 



SETARIA. 



1. Blades broad and plicately folded when young. Panicle 



open or almost spike-like 2 



Blades not plicately folded. Panicle spike-like 3 



2. Culms 5-12 ft. long. Blades 1-3J inches broad ... 



S. sulcata. 

 Culms 2-3 ft. long. Blades less than h in. broad ... 



S. liiidenbergiana. 



3. Blades deeply sagittate S. appendiculata. 



Blades not sagittate 4 



4. Annual. Panicle cylindric often lobed, dense or lax 5 

 Perennial. Panicle cylindric always dense 6 



5. Bristles of panicle with barbs reversed ... S. verticillata. 

 Bristles of panicle with barbs pointing upwards ... 6 



6. Culms slender weak. Blades 2-6 in. by 1-3 lin. Panicle 



i-3 in. by l£-2 lin S. imberbis. 



Culms often stout. Blades 6-18 in. by 3-10 lin. Panicle 

 li-12 in. by 4-12 lin S. italica. 



7. Lower glume 5, upper 7 nerved 8 



Lower glume 1-3, upper 5 nerved 



8. Blades 3-4 lin. broad. Tips of bristles thick and blackish. 



S. nigrirostis. 

 Blades l|-2 lin. broad. Tips of bristles not thickish. 



S. gerrardi. 



