102 Plant-Breeding 



ones which we oftenest desire to obtain. Another type 

 of variation that we constantly covet is something 

 that we call a new character, which will lead to the 

 production of a new cultural variety, and we are always 

 looking to this as the legitimate result of crossing. We 

 have forgotten if, indeed, we ever knew that the 

 commoner, all-pervading, more important function of the 

 cross is to introduce some new feature or power into the 

 offspring, to improve or to perpetuate an existing variety, 

 rather than to create a new one. Or, if a new one is 

 created, it comes from the gradual passing of one into 

 another, an inferior variety into a good one, a good one 

 into a superlative one. So nature usually employs crossing 

 in a process of slow or gradual improvement, one step 

 leading to another, and not in any bold or sudden creation 

 of new forms. And there is evidence to show that some- 

 thing akin to this must be done to secure the best and 

 most permanent results under cultivation. 



Rarity of natural hybrids. Think of the great rarity 

 of hybrids or pronounced crosses in nature. No doubt 

 all the authentic cases on record could be entered into 

 one or two volumes, but a list of all the individual plants 

 of the world could not be compressed into ten thousand 

 volumes. There are a few genera, in which the species 

 are not well defined, or in which some character of in- 

 florescence favors promiscuous crossing, in which hybrids 

 are conspicuous ; but even here the number of individual 

 hybrids is very small in comparison to the whole number 

 of individuals. That is, the hybrids are rare, while the 

 parents may be common. This is well illustrated even 

 in the willows and the oaks, in which, perhaps, hybrids 



