MUTUAL INFLUENCE OF THE STOCK AND GRAFT. 141 



In the Revue Horiicole for 1890, page 531, it is stated that Edward 

 Leport of France has demonstrated that in potatoes the stock influences 

 the graft in quality, nature of the flesh, color, and earliness. His method 

 of operation is not given. 



A writer in the Country Gentleman for 1870, page 326, states that he 

 grafted together two varieties of the potato, the old Pheasant-eye Kidney 

 and a red variety, leaving one eye on each piece when joined together. 

 The produce contained some red and some Pheasant-eye tubers, and two 

 or three tubers which were striped from the eyes. These latter he at first 

 believed to be graft-hybrids, but finding afterward some tubers having the 

 same appearance among a crop of the Pheasant-eye, he regarded them only 

 as sports. 



R. Munro, an English gardener, states in The Garden, (vol. XII, page 

 522), that he grafted a large number of distinct kinds of potato in the 

 usual manner, but in no instance was any case of " hybridism " obtained. 

 It is safe to say that it is not now believed by the best informed botanists 

 and horticulturists that new varieties of potato can be produced at will by 

 grafting the tubers. 



GRAFT HYBRIDS. 



I now come to consider the nature and permanence of the changes pro- 

 duced by grafting. Are these modifications of a truly hybrid character, 

 or are they, like the changes brought about by different soils and cli- 

 mates, the results of altered nutrition? 



Gf. J. Romanes, in the article on hybridity, in the Encyclopedia Britan- 

 nica > says: " It is well known that when two varieties or allied species are 

 grafted together, each retains its distinctive character. But to this gen- 

 eral, if not universal, rule there are on record several alleged exceptions, 

 in which either the scion is said to have partaken of the qualities of the 

 stock, the stock of the scion, or each to have affected the other. Supposing 

 any of these influences to have been exerted, the resulting product would 

 deserve to be called a graft-hybrid. It is clearly a matter of great inter- 

 est to ascertain whether such formation of hybrids by grafting is really 

 possible; for, if even one instance of such formation could be unequivo- 

 cally proved, it would show that sexual and asexual reproduction are 

 essentially identical. The cases of alleged graft-hybridism are exceedingly 

 few considering the enormous number of grafts that have been made every 

 year by horticulturists, and have been made for centuries. Of these cases 

 the most celebrated are those of Adam's laburnum (Cytisus Adami) and 

 the Bizzarria orange. * ' ■ The other instances of alleged graft- 

 hybridism are too numerous to be here noticed in detail; they refer to 

 jessamine, ash, hazel, vine, hyacinth, potato, beet, and rose. Of these the 

 cases of the vine, beet, and rose are the strongest as evidence of graft- 

 hybridzation, from the fact that some of them were produced as the result 

 of careful experiments made by very competent experimentalists. On the 

 whole, the result of some of these experiments, although so few in num- 

 ber, must be regarded as making out a strong case in favor of the possi- 

 bility of graft-hybridism. 



Burbidge, in his "Propagation of Plants," page 60, says: "We have 

 evidence which goes a long way toward proving that it is possible to 



19th edition, 1881, vol. XII, page 126. 



