LABOKATORY MANUAL OF HORTICULTUKE 



1. Make a natural-size drawing of the root, showing the diag- 

 onal cut and the cleft. How long should this cut be? Place 

 the dimensions on the drawing, and describe how the cut, which 

 should be clean and even, is best made. Discuss. 



2. Make a natural-size drawing of the scion, showing the cut and 

 the cleft. The scion should contain three or four well-developed 

 and plump buds. How long is the scion ? Label all parts, and 

 place the dimensions on your drawings. 



3. Show by a natural-size drawing the stock and the scion tied 

 in position. What size of stocks is best suited to this form of 



grafting ? What commercial 

 operation depends upon this 

 method of propagation ? What 

 superiority, if any, does a tree 

 produced by this method have 

 over a tree produced by bud- 

 ding ? When is the best time of 

 the year to do root grafting, and 

 why? Why is it essential to 

 have at least one side of the stock 

 and the scion flush with each 

 other? Where do you find the 

 cambium layer on the stock and 

 the scion ? Indicate on your 

 drawing by an arrow the loca- 

 tion of the cambium tissue. 



FIG. 28. Double-whip grafting 



DOUBLE-WHIP GRAFTING 



A, scion ; B, stock, showing the double 

 split ; C, scion inserted into the stock 



This is a modified form of whip 

 grafting in which two clefts are 

 made instead of one (Fig. 28). The scion, having two supports 

 in the stock, forms a more intimate contact with it. This method 

 is usually too slow for general practice, but is good in special 

 cases, particularly with some plants that are a little hard to graft. 

 Make a natural-size drawing of the stock and the scion. 

 Make a drawing of the stock with scion in position. Describe. 



REFERENCES : 



Bailey, " The Nursery Book," chap. v. 



Goff, " Principles of Plant Culture," pp. 219-230. 



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