84 THE PEACHES OF NEW YORK 



belief that it would not be mentioned were it not that many fruit-growers 

 still look to the action of pollen as the explanation of the phenomenon. 



Another, and a much more probable explanation, is that every sport- 

 ing peach or nectarine-tree is a more or less remote hybrid. There is 

 a growing belief that species are fixed and that crossing is the only source 

 of new seed- or bud-forms. Certainly all who have crossed plants in any 

 considerable numbers know that hybridity is at least one cause, and a 

 frequent one, of mutations. It is possible that sometime in the past the 

 peach and the nectarine were crossed, the offspring showing no trace of the 

 cross, and that now there is an occasional disassociation of the characters 

 brought together by such crossing. There are several objections to this 

 hypothesis. One is that two forms sufficiently distinct to induce so striking 

 a variation as a nectarine from a peach, must have differed in tree as well 

 as in fruit-characters and that these differences would crop out just as 

 smoothness of fruit so frequently does. Another, and less potent objec- 

 tion, is that the nectarine has never been found wild, that it never becomes 

 naturalized, that it is shorter-lived and less vigorous and behaves in general 

 like an artificial plant. 



The third, and at present the most acceptable theory, is that we have 

 in the nectarine from the peach what De Vries calls a retrogressive muta- 

 tion. That is, an active character, in this case pubescence on the fruit, 

 becomes latent and appears to be lost — a type of mutation frequent 

 among cultivated plants. The nectarine, then, is a peach with one char- 

 acter subtracted. When the nectarine yields a peach, the character is 

 restored. The one is a negative, the other a positive step; one is retro- 

 gressive, the other progressive mutation. The speculations as to what 

 causes these mutations are as yet too vague to be profitable. Probably 

 we can never make use of the cause by which mutations arise or of the con- 

 ditions leading to them until we can induce these strange variations. 

 That they are due to disturbances in the processes of cell-division is the 

 theory now current — sufficiently comprehensive and sufficiently vague 

 to be a most convenient explanation, at any rate. 



Nectarines do not attain the perfection in New York reached west 

 of the Rocky Mountains. The trees, possibly, are a little less manageable 

 in the orchard, less vigorous and certainly more susceptible to pests. 

 Nectarines, in particular, suffer more than peaches from the scoiirge of the 

 crescent sign, curciilio, a pest which finds all smooth-skinned stone-fruits 

 much to its taste and the nectarine more than others. Then, too, whether 



