OF PROPAGATION BY CUTTINGS. 205 



No farther precautions are taken with cuttings, 

 nor does it at first sight appear possible to suggest 

 any ; nevertheless, the enormous constitutional dif- 

 ference among plants is such, that, while numerous 

 species will strike without any difficulty under almost 

 any circumstances, with the wood ripe or half-ripe, 

 just formed or aged, there are many others which no 

 art has yet succeeded in converting into plants ; and 

 it is by no means uncommon to find that, out of a 

 potful of cuttings of the same species, apparently all 

 alike and subjected to exactly the same treatment, 

 one will grow and the remainder fail. It is, therefore, 

 one of the most probable of all things, that the prin- 

 ciples of striking cuttings are still very imperfectly 

 understood, and that this is one of the points of 

 horticulture in which there is the greatest room for 

 improvement. 



It may be worthy of inquiry whether bell glasses 

 of different colours will not produce different effects 

 upon cuttings, in consequence of their different power 

 of transmitting light. It has been shown by Dr. 

 Daubeny, in a very interesting paper in the Philoso- 

 phical Transactions for 1836, page 149, that glass of 

 different colours exercises very different effects upon 

 the plants exposed to the rays of solar light passing 

 through it ; that both the exhalation and absorption 

 of moisture by plants, so far as they depend upon the 

 influence of light, are affected in the greatest degree 



This consists of a eoUection of latent buds or fibres, from which 

 roots are emitted with much greater facility th an from any other 

 portion. A. J. D.] 



