SEX AND BEETILIZATIOS". 115 



varieties with great uniformity, but •when removed from 

 their natural habitats, a change in their offspring is usually 

 observable, and these variations may be intensified by 

 cultivation and other external causes. The first variation 

 may be considered the entering wedge, which will, if fol- 

 lowed up, divide and disintegrate the most stubborn of 

 species. 



The novice in horticultural matters will necessarily 

 need some other source of information in regard to 

 species and natural varieties than that acquired through 

 his own personal observation, and this is found in our 

 standard botanical works, but ib may be well to bear in 

 mind that their authors are as other men, not wholly 

 infallible, but probably as near right as the present state 

 of botanical science permits ; also that the acquirement of 

 true knowledge often tends to change the opinions of the 

 most learned. 



Taking our standard botanical works as a guide in the 

 classification of plants, we may say that most species 

 may be hybridized and varieties cross-fertilized. We 

 cannot say all may be, because we would have nothing 

 better than a mere theory on which to base such an as- 

 sertion, and it is well known that there are many closely 

 allied species that have successfully resisted all efforts to 

 hybridize them. For instance, no one has ever been able 

 to hybridize or produce a hybrid plant between the 

 Alpine StrawbeiTy of both Europe and America and any 

 other of the various species found in different parts of 

 the world. We might also naturally suppose that it 

 would not be diflScult to hybridize the different species 

 of the true Cherries ( Cerasus), but all the species and 

 varieties that produce their flowers in racemes have thus 

 far resisted all efforts to hybridize or cross them with 

 those which bear flowers in umbels. While I would not 

 venture to assert that the various species cannot be 

 hybridized, it is not at all probable that they ever will 



