O. N. Purvis 



361 



10 



Mayl6 31 Junes IS 2.6 



Fig. 14. Mean ratio of lumen diameter to wall thickness, in presence of added potash. 



Full Une ^^— Plot 7, no nitrogenous fertiliser added. 

 Broken line • - - Plot 9, nitrogenous fertiliser added. 



2/1 



I/i 



JL 



I 



May31 JooeS 15 2.6 



Fig. 15. Mean thickness of walls, xylem, in presence of added potash. 



Full line — Plot 7, no nitrogenous fertiliser added. 

 Broken line - - - Plot 9, nitrogenous fertiliser added. 



