30 FAMILIES OF FLOWERING PLANTS. 
both the infloresence consists of spikes or panicles, made up of small 
Fic. 29.—Dark green Bulrush (Scirpus 
atrovirens). After Britton and Brown, 
Ill. Fl. Northern U. S. 
spikelets; but the flower-bearing 
scale in a sedge is single, while in a 
grass 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 
sedge leaves are sometimes flat and 
grass-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, is entirely wanting 
in the sedges; and finally, the latter 
family have stems that are solid and 
more or less three-angled. Figure 
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. 
Fic. 30.—Bristly Sedge (Carex comosa). 
After BrittonZand Brown, Ill, Fl. North- 
ern U.S, 
