OF PROPAGATIOS" BY CUTTINGS. 197 



ceptional cases, and by no means affect the general 

 rule. Mr. Knight attempted to account for this, by 

 supposing that the powers which roots of various 

 forms, and cuttings, and other detached parts of 

 plants, possess of emitting foliage, " are wholly, and 

 in all cases, dependent upon the presence of true sap 

 previously deposited within them." {Hort. Trans., v. 

 242.) But this is a very obscure expression, and 

 does not seem to throw any light upon the subject. 



When the vine grows in a very warm damp stove, 

 its stem emits roots into the air ; the same thing hap- 

 pens to the Maize on the lower part of its stem ; and 

 in these and all such cases, the roots are found to be 

 emitted from buds. Hence it has been inferred that 

 the roots of a plant are as much productions of buds 

 as branches are, and that the stem is nothing more than 

 a collection of such roots held together under the form 

 of wood- and bark. The present is not the place for 

 a renewal of this discussion, for the arguments in 

 favor of and opposed to which, the reader is referred 

 to my Introduction to Botany, 3d edit. p. 309, &c. It 

 is sufficient here to remark that the question turns 

 upon whether the buds and leaves actually them- 

 selves produce robts, or merely furnish the organis- 

 able matter out of which roots are formed ; and that, 

 therefore, for the purpose of horticulture, either the 

 one or the other is equally capable of explaining the 

 facts connected with cuttings.' 



, * 



* The following curious fact, recorded by Mr. Liyingstone, which 

 seems to have escaped observation, deserves to be mentioned here : — 

 " The PterocarpuB Marsupium, one of the most beautiful of the large 



