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 examination 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. 
