142 



WEEDS OF FARM LAND 



a matter of fact, it is the pre-eminent weed in at least one- 

 third of the cases in which it is found, and further, it is 

 relatively seldom scarce except in the few instances in which 



it appears on heavier land. The lighter the soil, the more 

 likely is spurry to occur, and so it is even more closely as- 

 sociated with sand than with sandy loam and gravel. 



Annual knawel (Scleranthus annuus) (Fig. 37) is an in- 

 conspicuous weed that is easily overlooked, especially as it is 



