AN INDIVIDUAL PLANT IN ALL OF ITS RELATIONS. 141 



delicate structures against chill ; for securing the visits of 

 suitable insects, and warding off unsuitable insects ; and 

 for dispersing the seeds, need not be repeated. 



99. Branch buds. — If the plant under exanihuition be a 

 tree or shrub, branch buds will be observed to develop at 

 the end of the growing season (see Fig. 65). This device 

 for protecting growing tips through a season of dangerous 

 cold is very familiar to those living in the temperate 

 regions. The internodes do not elongate, hence the leaves 

 overlap ; they develop little or no chlorophyll, and become 

 scales. The protection afforded by these overlapping 

 scales is often increased by the development of hairs, or 

 by the secretion of mucilage or gum. 



