82 



FIRST BOOK OF GRASSES 



Examine Fig. 75, A, a joint of a raceme of one of 

 the broom sedges (Andropogon scoparius). It will 

 be seen to have the same general plan as a joint of 

 sorghum, and the racemes, shown in Fig. 75, B, 



though slender and flex- 

 uous, are in structure 

 similar to the racemes of 

 sorghum. The entire in- 

 florescence, however, is 

 very different. In sorg- 

 hum and Erianthus the 

 inflorescence is a leafless 

 terminal panicle, such as 

 is common in grasses. 

 The diagrammatic inflores- 

 cence (Fig. 75, B) shows 

 that the racemes of the 

 broom-sedge are borne on 

 numerous slender leafy 

 of Andropogon "scoparius; b, branches arising in the 

 IZlT * c ° mp ° und "^ axils of leaves on the 



main culm or branches, 

 the whole forming a compound inflorescence. The 

 leaves, especially the ultimate ones immediately 

 below the racemes, are mostly reduced to blade- 

 less sheaths and are sometimes bright colored. 

 Such transformed leaves subtending or surround- 

 ing single inflorescences are commonly termed 

 spathes. 



In some species the racemes are partly inclosed 



Fig. 75. A, single joint of raceme 



