PAPER SHELL WALNUTS 47 



the raising of these trees on a commercial scale. 

 It will be necessary to produce new varieties by 

 hybridization and selective breeding before these 

 nuts can be made popular. But, as before said, 

 there is every reason to believe that a series of 

 experiments looking to the production of im- 

 proved varieties would be more than justified by 

 the results obtained, and I shall point out in an- 

 other connection the commercial possibilities of 

 producing lumber trees in this way that make 

 the project doubly attractive. 



It may be well to call attention to one or two 

 peculiarities of the walnut that should be known 

 to anyone that attempts hybridizing experiments. 



In particular it should be understood that the 

 staminate flowers of the walnut usually bloom 

 and shed their pollen from one to four weeks 

 before the fruit-bearing nutlets appear. 



One would naturally suppose, under these 

 circumstances, that the pollen would all be lost 

 and that there could be no crop. But the pollen 

 appears to retain its vitality for a long time, and 

 even where it has been shed some weeks before , 

 the ripening of the pistillate flowers, there may 

 be a full crop. The hand-pollenizer must bear 

 in mind this tendency of the walnuts to mature 

 their flowers at different times. Still, as already 

 suggested, the pollen appears to retain its vital- 



