Alfalfa in Kansas. 



333 



are perennial weeds, their roots living over the winter and sending up 

 stems each year to produce seeds. Sorrel, or sour dock, propagates also 

 by means of running underground rootstocks, from which many new 

 stems are sent up. The perennial weeds are the most persistent, because 

 they can not be eradicated by merely preventing them from producing 

 seed for a few seasons. The plant and root must be entirely destroyed. 

 In the case of those weeds which possess running underground root- 

 stocks, eradication is a difficult problem. 



GREEN FOXTAIL. (Setaria viridis [L.] Beauv.). Green foxtail is a 

 very common annual plant closely resembling common millet. It 

 ranges from one to three feet high, the spreading branches springing up 

 from the crown of the plant. The flower head is from one to three inches 



long and covered with greenish 

 bristles. The root is fibrous. The 

 seeds ripen from July on. Yellow 

 foxtail is very similar to green 

 foxtail, and is almost always 

 closely associated with it as a 

 weed. These foxtail grasses are 

 bad weeds only because they are 

 so numerous that they choke out 

 crop plants. They also produce 

 an enormous crop of seed. 



The foxtails are easily killed 

 by cultivation. In the case of 

 alfalfa, cultivation with a spring- 

 tooth harrow or spike-tooth disk 

 horrow will help to keep them in 

 check. 



CRAB GRASS (Digitaria san- 

 guinalis [L.] Scop.). Crab grasp 

 is an annual grass, much branched 

 and leafy. It grows from one to 

 three feet high, the stems spread- 

 ing along the ground and' taking 

 root at the lower nodes or joints. 



The flowers and seeds are produced on slender finger-like spikes, from 

 which characteristic it is often called finger grass. Crab grass, as also 

 the foxtails, is primarily a weed of cultivated land, but seems to do well 

 in alfalfa fields and grass fields also, sometimes making such a vigorous 

 growth that it chokes the crop plants. 



This grass is more difficult to remove than foxtail because it roots so 

 readily at the joints. Cultivation will kill it. Do not let it go to seed. 

 CURLED DOCK (Rumex crispus L.). Curled dock is a perennial weed 

 with a large tap root, sometimes two feet long. The plant is from two to 

 three feet high and has large leaves with a wavy margin. The name 

 "curled dock" comes from the wavy appearance of its leaves. The flowers 

 and seeds are found at the top of the plant in dense whorls, extended into 

 racemes or heads. The mature seeds are shiny brown, and triangular in 



FiG. 278. Curled dock. 



