Bisexual Crosses 289 



and sugary varieties are in this respect wholly 

 constant, when cultivated separately. No 

 change is to be seen in the spikes. Further- 

 more it is very easy to make the crosses. The 

 best way is to cultivate both types in alternate 

 rows and to cut off the staminate panicles a few 

 days before they open their first flowers. If 

 this operation is done on all the individuals of 

 one variety, sparing all the panicles of the 

 other, it is manifest that all the plants will be- 

 come fertilized by the latter, and hence that the 

 castrated plants will only bear hybrid seeds. 



The experiment may be made in two ways ; by 

 castrating the sugary or the starchy variety. 

 In both cases the hybrid kernels are the same. 

 As to their composition they repeat the active 

 character of the starchy variety. The sugar is 

 only accumulated as a result of an incapacity 

 of changing it into starch, and the lack of this 

 capacity is to be considered as a retrogressive 

 varietal mark. The starch-producing unit- 

 character, which is active in the ordinary sorts 

 of corns, is therefore latent in sugar-corn. 



In order to reach the second generation, the 

 hybrid grains are sown under ordinary condi- 

 tions, but sufficiently distant from any other 

 variety of corn to insure pure fertilization. 

 The several individuals may be left to pollinate 



