THE USE OF SH00T8 FOR PROPAGATING 187 



In the case of the stock, h]i. represents the old wood of the 

 previous year, sli that of the current year, which was formed 

 before the budding operation was performed. In the bark, h 

 represents the bast fibres and t dead cells of the cut margin. 

 In making the T-shaped cut, the separation has occurred in 

 the youngest layers of the wood, a not infrequent occurrence 

 in practice, and the youngest wood vessels {y) and the cambium 

 (c) have remained attached to the bark. But often the reverse 

 takes place, and the cambium and young bast cells remain 

 attached to the wood. 



Already, after twelve hours, a change has taken place at the 

 margin of the cut, the cell-walls having become thickened and 

 assumed a yellow colour ; very soon new cell formation begins, 

 and in the case of strong stock with the formation of callus 

 {oh) in the splint-wood. On the lappets of the bark the 

 marginal cells full of protoplasm (Jc) first bulge out, and their 

 activity increases the nearer they are to the angle, where the 

 bast is still attached to the wood, until they form a consider- 

 able amount of callus (o/i). 



These masses of callus thus formed by the bast and the 

 wood and (under favourable conditions) by the scion unite into 

 a temporary covering for the wound. Later on the activity of 

 the cambial layer of the cortical lappets {cc), which represents 

 the continuation of the cambium of the uninjured portion of 

 the stem, becomes more pronounced ; this leads to the formation 

 of the actual and permanent wood parenchyma {kg) which 

 represents the commencement of a growth of wood which con- 

 tinues under slight amount of pressure. This parenchymatous 

 growth of wood, as it increases in amount, gradually crushes up 

 the thin-walled tissue which was first formed for the closure 

 of the wound. Gradually the whole of the tissue {ok) lying 

 between i and 2 is replaced by cells of the nature of kg, which 

 are filled with starch. 



The scion {E) is in this figure a bud with an attached por- 

 tion of cortical tissue, but without any wood cells ; the actual 

 bud lies in the direction of 0, somewhat higher than the 

 section represented in the figure, which only contains the 

 large fibro-vascular bundle {gh) belonging to it. On the right 

 of the chief bundle we see another smaller one, the correspond- 



