162 A MANUAL OF FARM GRASSES 



ANNUAL WEEDS 



The annual weedy grasses are numerous and often 

 troublesome. In general, annual grasses germinate in 

 the spring and become prominent in the summer and 

 autumn. Some, especially in the warmer parts of the 

 country, germinate in the fall, live over winter as small 

 tufts, and ripen their seed the following spring. In 

 fields annual grasses can usually be kept in subjection 

 by the ordinary methods of cultivation. In grain fields, 

 meadows and lawns other methods must be used. Clean 

 cultivation the preceding year, and the use of clean seed 

 will usually prevent the growth of a damaging amount of 

 weeds in grain fields. The same is true of meadows and 

 pastures but any lack of vigor in the forage grass, due 

 to a poor stand or a subsequent dying out, invites the 

 encroachment of weeds. A badly infested meadow or 

 pasture should be broken up and reseeded. It is a waste 

 of time to attempt to coddle such a field into good condi- 

 tion. Weedy lawns are discussed in another place (page 

 65). The common annual weedy grasses are mentioned 

 below. 



Crab grass (Syntherisma sangiiinalis (L.) Dulac and 

 sometimes also S. ischaemiim (Schreb.) Nash). Plants 

 spreading, in vigorous specimens becoming 3 or 4 feet in 

 diameter, some of the parts often showing a purplish 

 color, the sheaths covered with spreading hairs, the 

 blades flat, rather short, the flower head consisting of 

 several slender spikes, 3 to 6 inches long, radiating from 

 the top of the stem or from near the top. The spreading 

 stems may produce roots from the nodes, the, plant 



