THE USE OF SII00T8 FOR PROPAGATING 183 



the soil. Among- Conifers, Araucaria, Podoccajms, and Gingko 

 are mentioned as suited to such methods of propagation, espe- 

 cially if some bottom heat can be used. 



In the case of some plants ( Vitis vinifera and Pcconia 

 arborea) a special and advantageous method of propagation is 

 practised by means of eye-cuttings. The buds are cut out of 

 the old wood in the spring, in such a way that they resemble 

 eyes used for grafting, attached to a small piece of wood, and 

 the latter is placed with its cut surface downwards in pots in 

 a sandy soil. The pots are then sunk in a hot-bed. 



In plants, too, in which the axis is succulent, the eyes can 

 be cut out for propagating purposes (potatoes, &c.), or the 

 whole tuber may be cut in pieces. In this case we might 

 speak of tuber-cuttings. Their further growth is, as a rule, a 

 certainty, especially if the precaution is taken of keeping the 

 cuttings for a few days in a dry place before they are planted 

 in the ground. By so doing the foi-mation of a layer of cork 

 cells immediately below the cut surface is brought about, and 

 this constitutes the best protection of the soft and succulent 

 tissues against decay. 



§ 36. What object have we in view in budding and grafting, 

 and how are these operations best performed 



In budding and grafting, either one or several buds of the 

 mother-plant are detached and inserted on an older stock of the 

 same or of a similar kind. By this insertion of a younger 

 portion of a plant on an older stock the former can reap all 

 the advantages of the more advanced age of the latter, becomes 

 indeed older itself. 



Both processes necessitate the cutting of the tissues ; that 

 method will, therefore, be the best one in which the healing 

 of the wound takes place most rapidly and most completely. 



Tiie rapidity of healing depends (other things being equal) 

 upon the relative extent of the cambium, the layer which will 

 produce the healing tissue, as compared with the entire cut 

 surface. The greater the amount of cambium exposed on the 

 cut surface, the better are the chances of the graft or bud. 



