NATURAL GRAI-TS. Oo 



blue, while some produced tubers partly white and 

 partly blue. 



Adhesion of the axes of plants belonging to different species 

 is a more singular occurrence than the former, and is 

 of some interest as connected with the operation of 

 grafting. As a general rule horticulturists are of 

 opinion, and their opinion is borne out by facts, that 

 the operation of gi^afting, to be successful, must be 

 practised on plants of close botanical affinity. On the 

 other hand, it is equally true that some plants very 

 closely allied cannot be propagated in this manner. 

 Contact between the younger growdng tissues is essen- 

 tial to successful grafting as practised by the gardener, 

 and is probably quite as necessary in those cases where 

 the process takes place naturally. Although there is 

 little doubt but that some of the recorded instances of 

 natural or artificial grafting of plants of distant bo- 

 tanical affinities are untrustworthy, yet the instances 

 of adhesion between widely different plants are too 

 numerous and too well attested to allow of doubt. 

 Moreover, when parasitical plants are considered, such 

 as the Orobanches, the Cuscutas, and specially the 

 mistleto {Viscum), "v^hich may be found growing on 

 plants of very varied botanical relationship, the occur- 

 rence of occasional adhesion between plants of distant 

 affinity is not so much to be wondered at. Union be- 

 tween the haulms of wheat and rye, and other grasses, 

 has been recorded.^ Moquin-Tandon ' relates a case 

 wherein, by accident, a branch of a species of Soj^JtAyra 

 passed through the fork, made by two diverging 

 branches of an elder (Sambucus), growing in the 

 Jardin des Plantes of Toulouse. The branch of the 

 Sophora contracted a firm adhesion to the elder, and 

 what is remarkable is that, although the latter has much 



' Senebier, ' Phys. Vecet.,' t. iv, p. 426. The same author also cites 

 Bomer as having found two plants of Ranunculus, from the stem of 

 which emerged a daisy. As it is not an uncommon practice to stick a daisy 

 on a buttercup, it is to be hoped no hoax was played off on M. Romer. 



El. Ter. Veg.,' p. 289. 



