218 TEXTBOOK OF BOTANY 



duce more fruit. Apple and other fruit trees are pruned, 

 both to obtain more compact, better-shaped trees, and also 

 to cause the formation of less wood and more fruit. 



In the cultivation of wheat it is especially important to 

 encourage the development of axillary buds. In the axils of its 

 lower leaves a wheat plant bears buds, each of which may 

 develop into a stalk that ends in a head of grain . If the axillary 

 buds do not develop, each plant has but one stalk and one head. 

 Winter wheat, which begins its growth in the fall, develops 

 slowly. Its axillary buds remain close to the damp soil, send 

 out adventive roots, and so, being supplied with food, grow 

 into fruitful stalks. But spring wheat, whose seed germi- 

 nates in the spring, grows more rapidly. Its axillary buds 

 are carried up quickly above the surface of the ground, and 

 so are less likely to form roots and to grow into stalks. How- 

 ever, if the wheat field is rolled soon after the seeds have 

 germinated, the young plants are buried more deeply ; their 

 axillary buds remain for a longer time in or close to the soil, 

 form roots and stalks, and so the number of grain-bearing 

 heads on each plant is increased. 



Brussels sprouts are the axillary buds of a variety of cabbage 

 in which these buds develop instead of the terminal bud that 

 in other cabbage varieties grows into a single large head. 

 The development of the axillary sprouts is encouraged, not 

 in this case by destroying the terminal bud, but by removing 

 the leaves in whose axils the buds are borne. The tiger lily 

 bears bulb-like axillary buds, each of which may grow into a 

 new plant. The bulblets of " top onions " belong in the 

 same class. 



236. Adventive Buds. These may appear on practically 

 any part of the plant on the stem or branch, on a leaf, or 

 on a root. Very often they develop in response to the stim- 

 ulus of a wound. Plants differ greatly in their ability to 

 produce adventive buds. It is plain that a plant which reacts 

 to a wound stimulus by forming many adventive buds has 



