i8o 



BUDS AND BRANCHES 



breaking, use a bud that has been soaked in warm water for 

 an hour or two.) How many pairs of scales are there in 

 each set ? How does their arrangement correspond with 

 that of the leaf scars upon the stem ? What difference in 

 size and texture do you observe between 

 the outer and inner scales ? 



251. Nature of the Scales. — Hold up 

 to the light one of the scales from a 

 partly expanded bud and see whether 

 it is veined, and in what way. Does 

 this correspond with the venation of 

 foHage leaves ? Can you make out 

 what the scales represent ? Their 

 arrangement is the same as that of the 

 leaves, so they must represent the leaf 

 or some part of it, as the petiole or the 

 stipules. In the lilac and various other 

 buds they are found in all stages of 

 transition from scales to true leaves, 

 from which their real nature may readily 

 be inferred. In the common buckeye 

 and the horse-chestnut the transition is 

 not so apparent, but a comparison with 

 Figure 330 will show that they are 

 altered petioles. 



330- — 



the parts 

 buckeye 



Development of 

 of the bud in the 

 {after GRAY). 



252. Use of the Scales. — What purpose do the scales 

 serve .' You can best answer this question by asking 

 yourself what is the use of the shingles on the roof of a 

 house, or of the cloaks with which we wrap ourselves in 

 winter ? Notice how thick and hard the outer ones are, 

 and how the inner ones envelop the tender parts within 

 like blankets. As we sometimes coat our roofs with tar and 

 cement, so these scales, especially in cold climates, are often 

 coated with gum for greater security against the weather. 



253. Internal Structure of the Bud. — Make a cross sec- 

 tion of a bud and sketch it as it appears under the lens. 



