Inconstancy of Improved Races 793 



to return every year. They are ineradicable. 

 Every individual is in the possession of this 

 latent quality and liable to convert it into 

 activity as soon as the circumstances provoke 

 its appearance, as proved by the increase of an- 

 nuals in the early sowings. Hence the conclu- 

 sion that selection in the long run is not ade- 

 quate to deliver plants from injurious qualities. 

 Other proofs could be given by other biennials, 

 and among them the stray annual plants of 

 common carrots are perhaps the most noto- 

 rious. In my own cultures of evening-prim- 

 roses I have preferred the annuals and ex- 

 cluded the biennials, but without being able to 

 produce a pure annual race. As soon as cir- 

 cumstances are favorable, the biennials return 

 in large numbers. Cereals give analogous 

 proofs. Summer and winter varieties have 

 been cultivated separately for centuries, but in 

 trials it is often easv to convert the one into 

 the other. No real and definite isolation has 

 resulted from the effect of the long continued 

 unconscious selection. 



Striped flowers, striped fruits, and especially 

 striped radishes afford further examples. It 

 would be quite superfluous to dwell upon them. 

 Selection always tends to exclude the mono- 

 chromatic specimens, but does not prevent 

 their return in every generation. Numerous 



