204 Principles of Plant Culture. 
unite by grafting. Examples, the Ben Davis and Baldwin 
apples, the Bartlett and Seckel pears. 
Plants of different species of the same genus (21) often 
unite by grafting. Examples, the peach unites with the 
plum; many pears unite with the quince; the tomato unites 
with the potato. 
Plants of different genera in the same family or order (21) 
sometimes unite by grafting. Examples, the chestnut unites 
with the oak; the pear unites with the thorn, etc. 
The apparent resemblance of two plants of different 
species is not always evidence that they will unite by graft- 
ing; e. g., the peach and apricot, though resembling each 
other in many respects, do not readily unite by grafting, but 
both unite freely when worked upon the plum, though the 
latter apparently differs from both the peach and apricot 
more than these differ from each other. 
Many plants unite freely when grafted in one direction, 
that fail to unite when worked in the opposite direction: e. 
g., many cultivated cherries unite freely when worked upon 
the mahaleb cherry, while the latter fails to unite when 
worked upon any of the cultivated cherries; many pears 
unite freely when grafted upon the quince, but the quince 
does not freely unite when worked upon the pear. The 
only sure way of determining what species may be united 
by grafting is by trial. 
Three principal kinds of grafting are in use, viz., cion 
grafting, budding (394) and approach grafting (399). 
386. Cion Grafting is used in grafting on roots (root- 
grafting (391)), and very often in grafting on the stem, espe- 
cially on large trees. The cion (scion) is a short section of 
the dormant stem, of the variety it is desired to propagate. 
