6 TEXTBOOK OF BOTANY 



first, they carry to all parts of the leaf the water and other 

 substances that have been brought up from the roots ; and 

 second, they carry from all parts of the blade to the leaf- 

 stalk and so finally to other parts of the plant the food that 

 has been manufactured in the leaf. 



7. Tendrils. Here and there, growing from the same 

 level on the stem as one of the leaves, is a slender structure 

 that looks like a branch, but is more or less curved or coiled 

 (Fig. 3). If the end portion of a young tendril is gently 

 stroked on one side with the finger or with a pencil, it will 

 often begin to bend toward the object that is stroking it. It 

 is in this way that tendrils coil about the objects that they 

 touch. Some of the relatives of the cucumber climb by 

 means of their tendrils. But the tendrils of the cucumber 

 are not numerous enough or strong enough to support the 

 weight of any large part of the plant ; for this reason the 

 plant usually sprawls on the ground, although sometimes 

 the ends of branches clamber up a short distance on neighbor- 

 ing objects. However, with a little assistance, a cucumber 

 plant can be induced to climb. 



8. Terminal Buds. The tip of the stem is covered by 

 young leaves which have not yet unfolded. The stem tip 

 and the young leaves that cover it are together called a bud. 

 This bud includes not only the few leaves that one sees on the 

 outside ; for if these are stripped off, several smaller leaves 

 will be found within. As the part of the stem inclosed within 

 the bud grows, the distance between the older leaves of the 

 bud increases, and these older leaves unfold, leaving the next 

 younger leaves as the outer covering of the bud; at the 

 same time new leaves are being formed within the bud as 

 minute swellings upon the stem, just back of its very end. 

 It is by means of these changes within the bud that the stem 

 grows in length and that new leaves are formed. A part of 

 the stem for a short distance back of the bud is also growing 

 longer, but the older parts do not grow in length. There 



