202 



THE GREEN-HOUSE. 



What is to be done for a stock in this case ? All we 

 can say is. Choose some free-growing plant of the 

 same natm-al tribe or order, and as nearly allied to the 

 genus as possible. This will not always answer, but 

 it very often will, and at any rate it is the means by 

 which sagacity must discover experimentally what 

 will finally succeed. In general, all plants of the 

 same natural family will breed together ; that is, pro- 

 duce mules, if the operation of impregnation be care- 

 fully effected by art, and will also bud and graft toge- 

 ther. There are, however, numerous exceptions : 

 thus, no one has ever (as far as we have ascertained) 

 been able to produce a mule between the black and 

 red currant, often as it has been tried ; nor will a pear 

 grafted on apple, or the contrary, last above a year 

 or two. 



With respect to the effect of the stock on the scion, 

 that is as difficult to determine a priori as what plants 

 will succeed grafted on each other. Arguing from 

 what takes place in the case of fruit trees, we would 

 say that vigorous growing trees will be dwarfed and 

 thrown into a blossoming state, by being grafted on 

 low-rooted kinds with few ramose and many fibrous 

 roots ; as is the apple by being grafted on the paradise 

 variety, and the pear on the quince ; and in like man- 

 ner, that less robust kinds would have their vigour 

 and duration somewhat increased by being grafted on 

 free-growing branchy trees, as are the finer varieties 

 of apple and pear by being grafted on the crab and 

 wilding pear. Whether this universally holds or not 



