i68 



WEEDS OF FARM LAND 



(/3) Weeds Specially Associated with Wheat and Temporary 

 Grass and Clover (" Seeds "). 



TABLE XIII. WEEDS SPECIALLY ASSOCIATED WITH WHEAT AND 

 TEMPORARY GRASS AND CLOVER. 



These weeds resemble the others associated with "seeds" 

 crops in that they are seldom or never dominant. Most of 

 them are so small and inconspicuous that care has to be taken 

 in field work to give them their due weight of importance, as 

 it is easy to under-estimate the quantity present. Sandwort 

 (Arenaria serpyllifolia), mouse- ear chickweed (Cerastium 

 vulgatmri), and forget-me-not (Myosotis arvensis} occur more 

 frequently among seeds than among wheat, whereas lady's 

 mantle (Alchemilla arvensis) and wall speedwell (Veronica 

 arvensis) exhibit a greater preference for wheat. All of them 

 are relatively seldom seen among any other crops. 



(b) Weeds Discouraged by "Seeds" Crops. 



It has already been mentioned that the peculiar habit of 

 " seeds " crops is detrimental to the growth of many weeds. 

 Some of the commonest and most abundant farm weeds, in- 

 cluding several that are utterly indifferent to the nature of 

 the soil they frequent, cannot endure the close competition of 

 "seeds," and refuse to grow among them. The seeds and 

 underground parts of the weeds, perhaps after making a few 

 futile efforts to establish a position, simply remain dormant in 

 the soil until such time as the antagonistic crop is removed 

 and more favourable conditions supervene. Then, little the 

 worse for their waiting period, they reassert themselves among 

 the later crops in the rotation. 



