Fig. 1 



Fig. 2 



PLATE IV 



Fig. 1. — Thickened rootlets and proliferated root tips of corn injured by 

 0.1 per cent of copper added as copper sulphate to the soil. (X 3 diam.) 

 Fig. 2. — Fine roots and root tips of corn, normal. ( X 3 diam.) 

 (Photos by G. F. Freeman.) 



