APPENDIX. 
03 
comparatively worthless, we believe that this is owing not tc 
natural limits set upon the duration of a variety ; that it does 
not depend on the longevity of the parent tree ; hut uj- on the 
care with which the sort is propagated, and the nature of the 
climate or soil where the tree is grown. 
It is a well established fact, that a seedling tree, if allowed to 
grow on its own root, is always much longer lived, and often 
more vigorous than the same variety, when grafted upon 
another stock ; and experience has also proved that in propor- 
tion to the likeness or close relation between the stock and the 
graft is the long life of the grafted tree. Thus a variety of pear 
grafted on a healthy pear seedling, lasts almost as long as upon 
its own roots. Upon a thorn stock it does not endure so long. 
Upon a mountain ash rather less. Upon a quince stock still 
less ; until the average life of the pear tree when grafted on the 
quince, is reduced from fifty years — its ordinary duration on the 
pear stock — to about a dozen years. This is well known to 
every practical gardener, and it arises from the want of affinity 
between the quince stock and the pear graft. The latter is 
rendered dwarf in its habits, bears very early, and perishes 
equally soon. 
Next to this, the apparent decay of a variety is often caused 
by grafting upon unhealthy stocks. For although grafts of very 
vigorous habit have frequently the power of renovating in some 
measure, or for a time, the health of the stock, yet the tree, 
when it arrives at a bearing state, will, sooner or later, suffer 
from the diseased or feeble nature of the stock. 
Carelessness in selecting scions for engrafting, is another 
fertile source of degeneracy in varieties. Every good cultivator 
is aware that if grafts are cut from the ends of old bearing 
branches, exhausted by overbearing, the same feebleness of habit 
will, in a great degree, be shared by the young graft. And on 
the contrary, if the thrifty straight shoots that are thrown out 
by the upright extremities, or the strong limb-sprouts, are 
selected for grafting, they ensure vigorous growth, and healthy 
habit in the graft. 
Finally, unfavourable soil and climate are powerful agents in 
deteriorating varieties of fruit-trees. Certain sorts that have 
originated in a cold climate, are often short-lived and unproduc- 
tive when taken to warmer ones, and the reverse. This arises 
from a want of constitutional fitness for a climate different from 
its natural one. For this reason the Spitzenburgh apple soon 
degenerates, if planted in the colder parts of New England, and 
almost all northern sorts, if transplanted to Georgia. But this 
only proves that it is impossible to pass certain natural limits 
of fitness for climate, and not that the existence of the variety 
itself is in any way affected by these local failures. 
Any or all of these causes are sufficient to explain the appa- 
