32 Propagation. 



Suckers may be regarded as spontaneous layers, the new shoots 

 being sent up from buds on the roots or portions of the stem beneath 

 the surface of the ground. They are much employed in multiplying 

 most species of the raspberry. The runners of strawberries may be 

 regarded as layers or suckers above ground. 



III. GRAFTING. 



Upwards of twenty different modifications of grafting were men- 

 tioned by the ancient Roman writer, Varro ; and Thouin, of Paris, 

 lias described and figured more than a hundred kinds. The great 

 number of modes given in books has tended rather to bewilder than 

 to enlighten beginners ; the following remarks, therefore, are more 

 for the purpose of laying down reasons on which success depends, 

 than for pointing out the peculiar modes of operation, which may 

 be varied according to convenience, provided attention is given to 

 the essential particulars. 



Propagation by grafting differs mainly and essentially from increas- 

 ing by cuttings, by inserting the cutting into the growing-stock of 

 another tree instead of directly into the soil. The stock thus sup- 

 plies the sap, as the soil does in the case of a cutting ; and the graft, 

 instead of making roots of its own, extends its forming wood down- 

 wards, at the inner surface of the bark, into 'the stock itself. Hence 

 there are two chief requisites for success : the first, that the graft be 

 so set in the stock, that the sap may flow upwards without interrup- 

 tion ; and the second, that the forming-wood may extend downwards 

 uninterruptedly through the inner bark. -To effect these two requi- 

 sites, it is needful, first, that the operation be performed with a 

 sharp knife, that the vessels and pores may be cut smoothly and 

 evenly, and the two parts be brought into immediate and even con- 

 tact Secondly, that the operation be so contrived that a permanent 

 and considerable pressure be applied to keep all parts of these cut 

 faces closely together. Thirdly, that the line of division between 

 the inner bark and the wood should coincide or exactly correspond 

 in each ; for if the inner bark of the one sets wholly on the wood of 

 the other, the upward current through the wood and back through 

 the bark is broken, and the graft cannot flourish or grow. And, 

 fourthly, that the wounded parts made by the operation be effect- 

 ually excluded from the external air, chiefly to retain a due quantity 

 of moisture in the graft, but also to exclude the wet, until, by the 

 growth of the graft, the union is effected. 



i. The first requisite is best attained by keeping a keen, flat 

 bladed-knife to cut the faces, and another knife for other purposes. 



