62 GRAMINEAE (GRASS FAMILY) 
eat greedily, and its matted “couch”’ of interlacing rootstocks make 
it an unsurpassed soil-binder in steep gullies or on road embank- 
ments where the ground must be guarded against “ washouts.” 
But it is its very tenacity of life that makes it 
such a pest when it gets into cultivated 
ground. If it could be kept in its place, or 
were not so hard to kill when it gets out of 
bounds, it would be a welcome friend. 
The mischievous part of the plant is its 
jointed, branching, underground stem, or root- 
stock, which is capable of budding a new plant 
at every joint and taking such entire posses- 
sion of the soil that other plants growing with 
it are so crowded and starved as to yield very 
poor crops or none at all. The same joints 
from which the buds shoot above ground also 
send down clusters of fine, fibrous roots which 
absorb most of the plant-food and moisture. 
Culms one to three feet tall, with flat, ashy 
green leaves, smooth beneath but rough above, 
three inches to a foot long and about a third 
of an inch wide; sheaths smooth, shorter than 
the internodes. Fruiting spike erect, three to 
eight inches long, with spikelets sessile and 
alternately placed in each notch of the rachis 
with the broad side turned toward it; each 
contains three to seven seeds, which are about 
as long as a grain of wheat but not nearly so 
plump. Indeed the whole spike looks some- 
what like a slender head of wheat, and the 
grass is a near relative of that noble grain. 
Fia.31.—Quack- The glumes of some seeds have a short awn, 
ener aa or beard, and others have none; they do not 
shell readily, and often the entire spikelet 
breaks from the stalk. Too often the seed is an impurity of 
wheat, rye, barley, clover, and other grasses, particularly brome- 
grass and timothy. Also the plant is often infected with the 
fungous disease known as “stem rust” of wheat. (Fig. 31.) 
