154 THE BOOK OF NATURE STUDY 



trees may be effected by grafting, that is to say, by the insertion 

 on the stem of a portion of a shoot possessing a number of buds. 

 The stem is called the stock, and the inserted shoot the scion. 

 When the operation is properly carried out scion and stock 

 become organically connected through the union and subsequent 

 development of the cambial tissues. The stock, through which 

 water and mineral substances are supplied to the scion, to that 

 extent exercises an influence on the latter, so that we speak of 

 strong and weak stocks ; very rarely the scion assumes some 

 of the morphological characters of the stock, but generally 

 speaking stock and scion retain their individual characteristics. 

 Three kinds of stocks are available for use, namely, the Crab, 

 the Paradise, and the " Free stock." The Crab is a strong, 

 somewhat deeply rooting, hardy tree, and is used if standard 

 trees are required, that is to say, tall trees with a clean stem up 

 to a height of five feet. Standard apple trees on the Crab stock 

 come into bearing some ten years from the time of grafting, and 

 remain productive for from forty to seventy years. The Paradise 

 stock is believed to be an Asiatic variety of the wild apple. It 

 is dwarf in habit, has a short tap root and numerous fibrous 

 surface feeding rootlets. Apple trees on this stock are dwarf 

 (10 feet high), come into bearing four years from the time of 

 grafting, and remain productive for from twenty to twenty-five 

 years. For these reasons orchards of trees on the Paradise are now 

 much more frequently planted than those on the Crab stock. Free 

 stocks result from sowing the pips of varieties of cultivated apples. 

 They are sown in drills in the autumn ; when two years old the 

 seedling trees are transplanted into good soil at a distance apart 

 of two feet all round. They may be grafted in the succeeding 

 year. Trees on such stocks, while possessing fibrous surface 

 feeding roots, are intermediate as regards size, vigour, and 

 longevity between the Paradise and the Crab. One or two such 

 seedling trees should be grown in the school garden. There 

 are various slightly differing methods of grafting, namely, whip 

 and tongue grafting, saddle grafting, and crown grafting. The 

 principle, is however, the same in all, and depends upon the close 

 juxtaposition of the cambial layers of stock and scion with 

 protection from the atmosphere. The most suitable method 



