"Variation op Plants under Cultivation. 47 



by a branch or shoot-producing bud giving a shoot or branch 

 which differs from the rest of the plant in colour of flowers, colour 

 of leaves, form of leaves, or by having a different habit of growth, 

 such as by drooping its branches, being more erect or by some 

 other departure from the normal. This is known as dimorphism, 

 and is the cause of a great number of variations under cultivation. 

 In nature many of these are lost from want of propagation. In 

 cultivation they can be propagated and thus perpetuated. The 

 precise cause of these bud variations seems even more obscure 

 than those which are raised from seeds. 



There is in connection with this bud variation or dimorphism 

 a singular fact. This is, that the same " sport," as we call it 

 colloquially, may be produced at the same time in gardens 

 hundreds of miles apart. This is very noticeable in the case of 

 Chrysanthemums. These, like Roses, when they sport, have 

 generally the habit of the plant from which they have sprung, 

 but have the flowers of a different colour. In the Rose, however, 

 sometimes the flowers are the same as the parent, but the sport is 

 of a climbing habit, while the original is dwarf and non-climbing. 

 Many of our variegated and golden or white-leaved shrubs and 

 ornamental trees are produced in the same way. 



This naturally leads one to remark briefly upon the varia- 

 tions effected by means of grafting- one plant upon another. I 

 confess that this is a branch of my subject upon which I know 

 very little from my own experience, as the plants operated upon 

 in this way have nearly all been shrubs or trees. It is well-known, 

 of course, that fruit trees grown upon certain stocks are better 

 adapted for growing on some soils than other stocks, and that 

 certain varieties of fruits bear better upon some stocks than 

 otLers. So, also, some Roses bloom well and produce better 

 blooms upon the Briar stock than on the Manetti, and others, 

 which are useless on either, will do on their own roots. How 

 far they are affected one can hardly tell, but the quality of many 

 fruits must be influenced also by their stock. Why the Apple 

 grafted on the Crab does not become a Crab as well is not easily 

 explained, nor is it easy to say that the Crab stock does not affect 

 the flavour of the Apple. We know that Cytisus Adami, which 

 bears both purple and yellow flowers on the same tree, was 

 produced by grafting the purple Cytisus purpureus upon a yellow 

 Laburnum. 



