58 



THE TRUE GRASSES. 



cemes solitary, terminal upon the branches and culm, 

 subtended by sheathing leaves. Rachis slender, with- 

 out appendages ; flowering glume awned from the point 

 or from a narrow slit, or awnless. 



Species five, scattered through the tropics {A. spathi- 

 florus Kunth from Paraguay to Cuba). 



Sub-genus IV. Anadelphia (Hack, as a genus). Like 

 the preceding, but only a part or none of the sessile, $ 

 spikelets are accompanied by $ ones. 



Species one, in tropical Western Africa. 

 Sub-genus V. Arthrohphis {EuMastaxon Steud. as a 

 genus). Racemes mostly in pairs, rarely digitate or 

 panicled, the lateral ones sessile ; 

 joints of the rachis somewhat 

 thickened, not translucent. 

 Flowering glume usually bifid or 

 two-toothed. 



Species fifty, the majority 

 American [A. Virginians L. 

 [" Broom Sedge"] and its allies, 

 A. provincialis Lam., etc.). 



Sub-genus VI. A)iiphilopJiis. 

 Racemes digitate or panicled, all 

 pedicellate. Rachis-joints and 

 pedicels with a median, longitudi- 

 nal, translucent line. Flowering 

 glume pedicel-like, tapering into 

 an awn. 



Species fifteen, mostly of the 

 Old World. A. Ischcemum L. 

 (Fig. 17) of Central Europe and 

 Asia, and A. saccharoides Sw. of 

 America, belong here. 



Sub-genus VII. Sorghu m 

 (Pers. as a genus, Bhnnenbachia 

 Kol.). Racemes in panicles, fre- 

 quently with few (sometimes only 

 one) fertile spikelets. Rachis- 

 joints without a translucent line, empty glume usually 

 broad-lanceolate, finally indurated and shining. 



Fig. 17.— Andropogon Ischaz- 

 mum L. (After Nees, Gen. 

 Germ. I. 92.) B, a pair of 

 spikelets. 



