284 STEMS ROOT IN AIR. 



and exposed to a moderate temperature ; in April these pots were placed 

 upon a warm bed of tan ; and it was this, doubtless, which, a month 

 afterwards, excited vegetation. He expresses his opinion that all 

 Conifers may be multiplied in a similar manner if root cuttings are 

 employed in Spring. This opinion is not, howcTer, generally entertained 

 by others. 



When the Vine grows in a very warm damp stove, its stem 

 emits roots into the air ; the same thing happens 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 favour 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 themselves 

 produce roots, or merely furnish the organizable matter out of 

 which roots are formed; and that, therefore, for the purpose 

 of horticulture, either one or the other is equally capable of 

 jexplaining the facts connected with cuttings.* 



As far as physiology can explain the operation of propa- 



* The following curious fact, recorded by Mr. Livingstone, wHoh seems to have 

 escaped observation, deserves to be mentioned bere ; — " The Pterooarpus Marsupium, 

 one of tbe most beautiful of tbe large trees of the East Indies, and -which grows in the 

 greatest perfection about Malacca, affording, by its elegant wide-expanding boughs, 

 ^nd thick-spreading pinnated leaves, a shade equally delightful with the far-famed 

 Tamarind tree, is readily propagated by cuttings of all sizes, if planted even after 

 the pieces have been cut for many months, notwithstanding they appear quite dry, 

 and fit only for the fire.- I have witnessed some of three, four, five, six, and seven 

 inches in diameter, and ten or twelve feet long, come to be fine trees in a few years. 

 While watching the transformation of the log into the tree, I have been able to trace 

 the progress of the radicles ffom the buds, which began to shoot from the upper part 

 of the stump a few days after it had been placed in the ground, and marked their 

 progress till they reached the earth. By elevating the bark, minute fibres are seen to 

 descend contemporaneously as the bud shoots into a branch. ' In a few weeks these 

 are seen to interlace each other. In less than two years the living fibrous system is 

 complete ; in five years no vestige of its log origin can be perceived ; its diameter and 

 height are doubled, and the tree is in all respects as elegant and beautiful as if it had 

 been produced from seed." {Hort. Trails., iv. 226.) 



