PROPAGATION. 249 



tainly the whole of the shoot ; we mention this rather to show 

 the nature of plants than to recommend it as a practice. 



The process of rooting is much longer in some plants than 

 others, and the difficulty therefore consists in maintaining the 

 shoot or cutting alive while it is going on, until it is able to 

 support itself, and it is in the length of time a thing takes to 

 root, that all the difficulty consists. In some cases the diffi- 

 culty amounts almost to prohibition, and it is in these that 

 we resort to layering, that by continuing just enough of the 

 parent support to prevent the part from dying, we may give 

 the intended new plant a year, or at least a season, to do its 

 work in, whereas it would require the utmost ingenuity, skill, 

 and attention, so to preserve the life of a cutting as to enable 

 it to root. It is said of the mulberry-tree, that if a healthy 

 branch be cut off at the heel, and be planted two or three 

 feet in the ground, it will root, and become a tree ; and there 

 are records of such being used for posts, or some other pur- 

 pose, having become fine bearing trees ; but ' these are excep- 

 tions to the general rule, because we have tried this, as well 

 as many other experiments, and have failed; though we have 

 not the least reason to doubt that where the soil has been 

 congenial, the wood healthy, and circumstances of moisture, 

 station, and perhaps climate favourable, these large branches 

 or limbs have been known to strike root, and to flourish 

 afterwards. AYe do not recommend the experiment, because 

 we think it may cause a loss of time if depended on for a 

 tree, and if not depended on, it may as well be let alone. 

 We certainly have known a limb of the mulberry that was 

 lying on the ground grow all along the upper surface, and 

 when removed, it was found to have struck root in many 

 places on the under side. It appears to us as a general prin- 

 ciple, that the rooting of cuttings is invariably promoted by 

 the soil they are in being of a higher temperature than the air 

 above ; hence, autumn is always the best time to insert out- 

 of-door cuttings, — the earth has had all the warmth of sum- 

 mer, and is of a higher temperature than the atmosphere in 

 general. The same cuttings that do well in autumn will not 

 do so well in spring, for then the earth has the chill of winter 

 in it, and the general atmosphere is for a long time warmer 

 than the soil. The cuttings first form a sort of callus, which 

 is like a spongy swelling at the base, and they take nourish- 

 ment from this before the spongioles or fibres appear. It is 



