106 PANICACE.E. 



c. Peduncles 1 mm. or more diam (d) 



d. Blades lance-ovate, 3 mm. long 18 



d. Blades much longer 19, 20 



D. EcHiNOCHLOA (Beauv. as a genus). Spikelets imbricate, strike//, 

 sessile or on short pedicels on two sides of a triangular rachis, 

 usually rough luith stiff hairs, the third glume of ten awl-pointed 

 or awned. Usually coarse plants; only a slightly distinct sec- 

 tion of Panicum. 



Spikelets 5 mm. or more long , ... 20 



Spikelets less than 5 mm. long (a) 



a. Spikes simple, about 2 cm. long 21, 22 



a. Spikes more or less compound 22, 23 



E. Ptychophyllum (Braun as a genus). Tall with ample leaves. 

 Panicle simple or compound, many-flotvered. Spikelets siibses- 

 sile, siibtended by a solitary bristle, which seems to connect these 

 species with Chamwraphis {Setaria). The setae of this section, 

 however, are merely the tips of the ultimate spikelet-bearing 

 branches of the panicle, whereas tlie setae of Chammraphis are 

 abortive branchlets, forming a kind of involucre below the spike- 

 let. A small and distinct section 24, 25^ 



F. Hymenachn^e (Beauv. as a genus). Spikelets small or minute 

 in a spikelike panicle. Species 5 or 6 26 



G. EuPANicuM. Spikelets in panicles, awnless, mostly pedicellate. 

 Containing about 200 species, strictly normal in structure. 

 Several of the cultivated Millets belong in this section. (K. M.) 

 K. Virgaria '\^Ym. Spikelets j^ointed, often in pairs. Branches 



of the panicle mostly angular. 



Stiff hairs on the pedicels 27 



No bristles nor stiff hairs on the pedicels (a) 



a. Spikelets conspicuously white, pubescent 28- 



a. Spikelets with appressed. silky hairs as seen by a 



lens 29 



a. Spikelets not white, pubescent nor hairy (b) 



b. Spikelets clothed with short hairs from callus- 

 bases 30 



b. Spikelets smooth or slightly rough (c) 



