WEEDS OF ARABLE LAND 115 



FIG. 32. Persicaria or Redshank (Polygonum Persicaria L.) ; a. young seedling ; 

 t. seedling more advanced in growth ; c. and d. flowering plant ; e. raceme 

 of flowers. All x about \. 



proportion of nitrogen, phosphoric acid, potash and 

 lime. As to spraying, see p. 47. 



Knotgrass (Polygonum Aviculare L.) may frequently 



