174 



AGRICULTURE ON THE PACIFIC SLOPE 



into the soil. You can see how this is done by putting 

 them on the surface of moist soil or moist cotton (fig- 

 ure 90). The suface of the soil should be loose to get 

 the best results. 



Sheep Sorrel. This little plant is very hard to get rid 



FIG. 90. Filaree seed burrowing into moist cotton. 



of when once it takes possession of a field. In its early 

 stages, as shown in figure 91, it is easily killed. 



West of the Sierra Nevada the following annual 

 weeds are especially important. 



Napa thistle. The Napa thistle (called also tocalote 

 and prickly tarweed) is one of the worst annual weeds 



