162 THE PRINCIPLES OF FLORICULTURE 



short-jointed shoots from near the base of the plant are 

 considered best for propagation. 



129. Essential characters of cutting material. In the 

 seed, the vital part is the embryo, while surrounding this 

 is an abundance of reserve food for its nourishment until 

 roots have developed. In the cutting, the vital part lies 

 in those specialized cells which constitute the bud ; this is 

 the growing-point. 



It is important in making the cutting to take with the 

 bud some plant tissue from the parent. This tissue con- 

 tains reserve food, and serves to nourish the growing-point 

 for a short time during the process of the formation of 

 roots. This tissue also has the power of assimilating new 

 food through the agency of the chlorophyll bodies of the 

 leaf and the carbon dioxide taken in through the stomata. 

 There should, therefore, be enough of this extra cell struc- 

 ture to keep up protoplasmic development during root for- 

 mation. Still, there should not be too much leaf surface, 

 or transpiration of moisture will be too rapid, and wilting 

 of the cutting will result. 



130. Conditions essential for successfully rooting 

 cuttings. Correct soil temperature and moisture, at- 

 mospheric temperature and moisture, light and a proper 

 amount of plant food are necessary for rooting cuttings 

 successfully. 



Soil temperature. Protoplasmic development and con- 

 sequent growth go on most rapidly under warm, moist 

 conditions. Therefore, it is necessary that the tempera- 

 ture of the medium in which cuttings are placed be warm. 

 The degree of temperature varies with different species, 

 but as with the germination of seeds, it should be about 

 the same as that required for the development of the 

 matured plant. In rooting cuttings, it is essential that 



