196 THE PHYSIOLOGY OF PLANTS 



become bigger and fruit later ; on the crab-apple the tree 

 retains a normal growth, but the crown does not produce 

 flowers for a considerable time. In the case of pears, the 

 quince and the damp-loving hawthorn will form dwarf stock. 

 Trees with such stock, however, are known to have a shorter 

 duration of life than when true wild stock is used. 



Quite a number of further statements exist, which we shall 

 partly repeat here, not so much to put forward these cases as 

 of general moment, but rather to give an impulse to new 

 experiments in this direction. Unfortunately there is a great 

 want so far of systematically arranged experiments. 



It is generally held that tree-like forms succeed better on 

 bushes than the reverse. Sour cherries grafted upon sweet 

 ones succeed less well than the latter upon the former. 

 Cabanis states that late varieties of walnuts and chestnuts 

 never succeed upon early varieties ; while in the case of pears 

 and apples. &c., this method of grafting late varieties upon 

 early ones is said to have very good effect. The same holds good 

 with peaches, and causes an earlier ripening of the fruits. 

 Almonds on plums and the reverse will i-eadily grow, but 

 seem to deteriorate after a few years. The almonds grow 

 more rapidly and commence earlier in the spring, and they also 

 form a very large callus growth. It may be safely assumed 

 that a very early scion, which requires constantly more water 

 than the stock, will succeed upon a less vigorous stock only so 

 long as the stock is able to supply the requisite water. If 

 the scion cannot suit itself to the stock, it will soon perish from 

 want of food matter. But the nature of the soil, the water 

 supply, and the variety are three factors which cause a great 

 amount of variation in the results. On the other hand, a stock 

 which begins to function eai'ly in spring and forms a large 

 amount of wood will supply a more or less exacting scion with 

 more sap than it will be able to make use of. The superfluous 

 material of the stock will tend to the rapid production of new 

 growths. If the wild stock possesses many buds, its energy 

 will expend itself in the development of long shoots ; but if, as 

 is generally the case, the lateral branches and eyes have been 

 removed, the snpei-fluous material will become lodged in the 

 cambium of the stem, and will cause the formation of large 



