GRAFTING 427 



elusion that "the graft does influence the general nutri- 

 tion of the plant, and that its influence is manifested: 



"1. By modifying the dimensions of the vegetative apparatus 

 of the subject and of the graft. 



" 2. By modifying the taste and the size of the edible parts, 

 their chemical composition, and the time of their appearance upon 

 the plant. 



"3. By modifying the rapidity with which the reproductive 

 organs appear upon the graft. _ 



" 4. By modifying the relative resistance of the two plants to 

 parasites and to external agents. 



"The physiological copartnership seems to be entered 

 into upon restricted lines. The general structure of the 

 scion and the stock remain unchanged: each has its own 

 forms of tissues, its own mode of secondary growth, 

 its own formation of bark, and maintains its strong 

 individuality." 



Strasburger points out "that the scion and stock do 

 exert some influence upon one another, for when annual 

 plants are grafted upon biennial or perennial stocks, 

 they attain an extended period of existence." He 

 also adds that "in special cases they do mutally exert, 

 morphologically, a modifying effect upon each other 

 (graft hybrids)." 



McCallum gives a number of interesting examples of 

 modifications in scion and stock following grafting. 

 " In the leaves of Epiphyllum are found certain albumen 

 bodies not found in the leaves of the related plant 

 Peireskia. Mitosch grafted Epiphyllum scions upon 

 Perireskia stocks, and in the leaves which subsequently 

 developed upon the latter found similar bodies." 



The most interesting graft-hybrid, and the only one it 

 seems worth while to mention, is the Cytisus adami, 

 which is a most striking example of what may happen 

 when grafting is successful. The Cytisus vulgare is a 

 large tree bearing racemes of yellow flowers; Cytisus 

 purpureus a shrub of small size bearing racemes of 

 small purple flowers. In 1826, J. L. Adam tried the ex- 

 periment of grafting the latter upon the former and 



