PROPAGATION BY GRAFTING, ETC. 241 



frages, potentillas, &c. The joints of these plants rest naturally on the 

 ground, send roots downwards, and leaves or shoots upwards; and being 

 separated from the internodi of the stolones, 

 constitute rooted plants. Very little assistance 

 from art is required in this mode of propagation ; 

 but the soil may be loosened and enriched, and 

 the joint pressed firmly against the soil, by peg- 

 ging it down with a hooked peg, or by laying 

 a small stone on each side of the joint. The 

 principal plant propagated in this manner in 

 gardens is the strawberry. 



Simple division is an obvious mode of pro- 

 pagating all herbaceous perennials, not bulb- 

 bearing, and all shrubs which produce nume- 

 rous suckers. The most common mode is to 

 take up the entire plant, and separate it into Buds developed below in 

 as many stems as have roots attached ; or if consequence of the scales 



if j ^ i being closely compressed 



only a few plants are wanted, these may be at t * 



taken off the sides of the plant without greatly 

 disturbing the interior of the root stock. 



Propagation by Grafting, Inarching, and Budding. 



The term graft is in England generally confined to one mode of 

 performing that operation viz., grafting with detached scions ; but it 

 is our intention in this article to use it, in the Continental sense, as 

 a generic term, including also, inarching, or grafting with attached 

 scions, and budding or grafting by means of a bud attached to a plate 

 of bark. The principle on which all these operations are founded is 

 the phenomenon of the union of newly- generated tissues when in the 

 act of being generated. No union can take place between the parts of 

 plants previously formed, but only when these parts are in the act of 

 forming. Thus two shoots or branches may be selected, and by means 

 of similar sections be most accurately joined, and placed under the 

 most favourable circumstances for uniting, as in fig. 193, representing 

 a stock and a scion ; yet when the two are bound together, though a 

 union ultimately does take place, not one particle of the existing tissue 

 at the time of grafting becomes united with similar tissue brought in 

 contact with it. Close contact is all that takes place with regard to 

 these surfaces of the scion and stock, for a vital union only occurs 

 when nascent tissues meet. The parts a, a, which are alburnum of 

 the preceding year, never unite. The vital union is formed solely 

 by the coalition of newly-generated tissues, thrown out by such parts 

 as have the power of generating them. This power does not exist in 

 the heart-wood, nor in the outer bark, but only in the alburnum, or 

 rather the substance embedded between it and the inner bark, con- 

 stituting the cambium, represented by the lines 6, b. If the sections 

 are placed against each other, so that the inner barks coincide, the 

 scion may perhaps derive an immediate supply of moisture ; but it 



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