Jul. 230, Bureau of Plant Industry, U. S. Dept. of Agriculture. 



Plate I. 



4 



"'/ x 



N 



1 



z 



1 Brl ^^B 



r • ! a^ ^^ 



w ^^^ ^F 



'^^ 



Hi m. \ 



> )J 







Fig. 1.— Balanced System Containing Opuntia and Squash. Figs. 2 and 3.— Pots 

 Sealed with Wax, Showing Kubanka Wheat Seedlings Pushing Through the 

 Wax Seal. The Wax is Applied Immediately after Planting the Seeds. 



