THE ART OF BUDDING AND GRAFTING 39 



stances for future use. Man has taken advantage of this fact 

 and uses potatoes, onions and many other fleshy steins for food. 



But one of the most important of the secondary functions 

 of the stem is reproduction This is accomplished by under- 

 ground stems, by the branching and the breaking-up of the 

 root stocks, and by the budding or formation of bulblets in the 

 bulb types. Many plants, lilies and hyacinths, have practically 

 lost their power to produce seeds and depend entirely upon this 

 method of reproduction. Irish potatoes are very generally 

 grown from tubers, but they will occasionally produce seeds, and 

 the wild potatoes of South America produce seeds very freely. 

 The growing of bulbs of ornamental plants is a leading industry 

 in many parts of the world. Holland is one of the greatest of 

 the bulb-producing countries of the world. 



Many aerial stems reproduce by runners and offsets and we 

 depend largely upon this method of reproduction to secure 

 plants for agricultural purposes. This is the regular method 

 of propagating strawberry plants. Branches of many plants 

 when set in the soil will produce roots and grow rapidly, and in 

 nature broken branches of willows and many other plants catch 

 in the soil or become partially covered and grow. We have 

 taken advantage of this tendency and propagate many useful 

 plants from cuttings. 



The art of budding and grafting is based on this tendency of 

 cuttings to grow under favorable conditions. Budding consists 

 in setting the buds of one plant within the bark of another plant, 

 and is generally used in propagating peaches, cherries and sim- 

 ilar fruits. Grafting consists in setting a part of a living twig 

 with its buds from one tree into the branch of another and is 

 very generally used in propagating apples and similar fruits. 



The structure of stems, their methods of growth and the 

 movements of the plant juices through them will be taken up 

 in a later chapter. 



In the first chapter we learned that plants are made up of 



