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usually consist of a large number of strains which differ from each 

 other on account of evolutionary changes which have occurred in 

 the past, and the breeder can by selection secure the strains which are 

 of greatest value. 



A few instances are known in which important changes have been 

 brought about by persistent selection. De Vries, by continued 

 selection from a 13-rayed strain of Chrysanthemum segetum, was 

 finally able to produce a double-flowered variety. Burbank found 

 a single specimen of California poppy which had a scarlet line on 

 one of its petals. By persistent selection from this plant he was 

 able to get a scarlet poppy. Cases of this kind are not understood, 

 yet they are important from the standpoint of the breeder. They 

 show that we have much yet to learn in this important field. It 

 may be stated that scarlet-flowered California poppies occasionally 

 occur in nature. This fact shows that at least part of the species 

 has the scarlet color factor. It is probable, therefore, that Burbank 

 started with a plant having this factor, and by selection merely 

 eliminated other color factors. 



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It is a well-known fact that when a crop is moved to a locality 

 which is radically different from that in vhich it was previously 

 grown it sometimes behaves in a surprising manner, presenting 

 unlooked-for variations. This subject has not been studied nearly as 

 much as it ought to be. We really do not know the behavior of the 

 variations which occur under such conditions, because so little atten- 

 tion has been given to them. 



Take, for instance, the case of the tomato in southern climates. 

 Some of the standard varieties of tomatoes present very peculiar 

 modifications when seed grown in the North is planted in the far 

 South. The first year the fruit is normal and resembles the fruit 

 that would have been produced in the North; but if seed of the south- 

 ern-grown fruit be saved and planted, the next year the fruit is of a 

 very different character and remains so from generation to genera- 

 tion under the new conditions. The writer is informed by Mr. 

 W. W. Tracy, sr., of this Bureau, that when the seed of these trans- 

 formed tomatoes is taken back to the North and planted, while the 

 first year it grows the southern type of tomato, the next year it 

 reverts to its northern form. Cases of this kind are well worth more 

 attention than they have received. 



It is to be noted that in the case of the tomato just referred to the 

 same change occurs in all the individuals. In this connection, 

 some work recently done by Dr. Albert Mann, of this Bureau, is of 

 special interest. Although the results are as yet unpublished Doctor 

 Mann kindly permits me to refer to them, 



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