BTJDS AND BRANCHES 



91 



82. Nature of the bud and its coverings. A "bud is an unde- 

 veloped shoot; or, in other words, a bud is a group of undevel- 

 oped parts which, under favorable circumstances, will grow 

 into some kind of stem and leaves. If it is a leaf bud, like the 

 majority of the buds on most forest trees familiar to us, it will 

 grow into a leafy branch or con- 

 tinue the growth of the main stem 

 at its tip. If it is a flower bud, it 

 will grow into that kind of spe- 

 cialized branch which we call a 

 flower. If it is a mixed bud, it will 

 grow into one or more flowers and 

 will also develop some ordinary 

 leaves. 



The scales which cover buds 

 are often dwarfed and otherwise 

 modified leaves or leafstalks, as 

 is well shown in some buckeyes 

 in which the opening buds present 

 a series of gradations between 

 mere scales and foliage leaves 

 (Fig. 73). In other cases, as in 

 oaks, beeches, lindens, and mag- 

 nolias, the scales represent the 

 appendages (stipules') found at 

 the bases of many leaves. 1 Fre- 

 quently bud scales are covered 

 with a dense layer of hairs or 

 down, and sometimes, as in the 

 balm-of-Gilead poplar, they are 

 cemented together by a resinous varnish. These coatings on 

 the scales of materials which do not readily conduct heat in- 

 crease their value as a protection against sudden changes in the 

 weather during the colder months. 



1 See Kerner-Oliver, Natural History of Plants, Vol. I, pp. 351-353. 

 Henry Holt and Company, New York. 



FIG. 73. Dissected bud of sweet 



buckeye, showing transitions from 



bud scales to leaves 



