No. 4.] CKOSSING OF PLANTS. 29 



parents of given attributes. There is something captivating 

 about the notion. It smacks of a somewhat magic power 

 which man evokes as he passes his wand over the untamed 

 forces of nature. But the wand is often only a gilded stick, 

 and is apt to serve no better purpose than the drum major's 

 pretentious baton. 



Let me say further that crossing alone can accomplish 

 comparatively little. The chief power in the evolution or 

 progression of plants appears to be selection, or, as Darwin 

 puts it, the law of "preservation of favorable individual 

 differences and variations, and the destruction of those which 

 are injurious." Selection is the force which augments, 

 develops and fixes types. Man must not only practice a 

 judicious selection of parents from which the cross is to 

 come, which is in reality but the exercise of a choice, but he 

 must constantly select the best from among the crosses, in 

 order to maintain a high degree of usefulness and to make 

 any advancement ; and it sometimes happens that the selec- 

 tion is much more important to the cultivator than the 

 crossing. I do not wish to discourage the crossing of plants, 

 but I do desire to dispel the charm which too often hangs 

 about it. 



Further discussion of this subject naturally falls under two 

 heads : the improvement of existing types or varieties by 

 means of crossing, and the summary production of new 

 varieties. I have already stated that the former office is the 

 more important one, and the proposition is easy of proof. 

 It is the chief use which nature makes of crossing, —to 

 strengthen the type. Think, for instance, of the great 

 rarity of hybrids or pronounced crosses in nature. No 

 doubt all the authentic cases on record could be entered 

 in 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 denned or in which some char- 

 acter of inflorescence 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 



