STOCK AND SCION MUST HAVE THE SAME CONSTITUTION. 845 



and yellow-forming theirs. Thus the limit between the scion 

 and its stock is unmistakeably traceable, and, notwithstanding 

 the combination of the two sorts in one, each perseveringly 

 retains that which is natural to it. 



It hence becomes evident that no junction can be permanent 

 unless the stock and scion have a great similarity, not only in 

 every part of their structure, but also in constitution, and that 

 the strictest consanguinity alone offers security that a grafted 

 plant shall be as durable as each of the two individuals thus 

 artificially joined is when left on its own roots. A temporary 

 union may indeed be effected, but it is soon dissolved, as we 

 everywhere see ra collections where grafted varieties are 

 brought together instead of plants " on their own bottom." 



" A detached portion of a plant is not merely capable of 

 producing the organs necessary to the formation of a. perfect 

 plant, but it has also the property of being able to blend with 

 another plant, and lead a common life with it. On this 

 capability depend the numerous garden operations which are 

 known under the not very apt name of ennobling {veredehi, 

 grafting). The contact of young succulent parts, which are in 

 the course of development, is a necessary condition of this 

 blending. Such a condition is very easily brought about in 

 dicotyledonous plants, because in them there exists between 

 the bark and wood. that layer of young tissue in course of 

 development called cambivm ; and there is little difficulty in so 

 bringing together two plants, that this layer in each shall meet 

 at some one point. But in the monocotyledons, in which the 

 vascular bundles lie scattered through the whole stem, and no 

 definite cambium layer exists, the conditions are far more 

 unfavourable. It is true, according to De CandoUe's account 

 that Baumann, of BoUwiUer, succeeded in grafting Draccena 

 ferrea on D. termmalis; but the scion died after the first year 

 The experiments, indeed, of Caldrini on grafting Grasses had 

 a more favourable result, for he succeeded in grafting even 

 species of different genera, such as Eice upon Panicvm cms 

 galh This result may be explained by the fact that in Grasses 

 the lower paxt of the internodes enclosed in the leaf-sheath 

 remains for a long time soft and succulent. A second and 



