30 



FAMILIES OF FLOWERING PLANTS. 



both the infloresence consists of spikes or panicles, made up of small 



spikelets: but the flower -bearing 

 scale in a sedge is single, while in a 

 o-rass it is double. Moreover the 

 sedges often exhibit some traces of a 

 floral envelope in the shape of a 

 crown of bristles, while the grasses 

 are quite destitute of perianth. The 

 sedffe leaves are sometimes flat and 

 ofrass-like, sometimes slender and 

 wiry, or "terete," as they are tech- 

 nically called. ' The little thong- 

 shaped appendage called a ligule, 

 borne at the junction of leaf and 

 stem in grasses, 18 entirely wanting 

 in the sedges; and finally, the latter 

 Pig. 29.-Dark green Bulrush (scirpus family havc stcms that are solid and 



atrovirens). After Britton and Brown. "^ i i i-i- 



lu. Fi. Northern u. s. morc or Icss threc-anglcd. l^igure 



28 illustrates a species of Cyperus 

 common in the eastern United States, and will afford a good idea of 

 the general plan of structure in the group. Figures 29 and 30 repre- 

 sent types of the two large genera Scirpus and Carex. 



Fig. 30.— Bristly Sedge (Carex comosa). 

 After Britton>nd Brown, 111. Fl. North- 

 ern U. S. 



