BUDS AND BRANCHES 145 



axils of leaves or from bracts, which are merely reduced 

 leaves. What, then, is the essential nature of flower stems ? 

 164. Significance of the clustered arrangement. As a 

 general thing the clustered arrangement marks a higher stage 

 of development than the solitary, just as in human life the 

 rudest social state is a distinct advance upon the isolated 

 condition of the savage. In plant life it is the beginning of 

 a system of cooperation and division of labor among the as- 

 sociated members of the flower cluster, as will be seen later 

 when we take up the study of the flower. 



Practical Questions 



1. Name as many solitary flowers as you can think of. 



2. Do you, as a rule, find very small flowers solitary, or in clusters ? 



3. Would the separate flowers of the clover, parsley, or grape be readily 

 distinguished by the eye among a mass of foliage ? 



4. Should you judge from these facts that it is, in general, advantageous 

 to plants for their flowers to be conspicuous ? 



Field Work 



(1) In connection with 144-154, the characteristic modes of branch- 

 ing among the common trees and shrubs of each neighborhood should be 

 observed and accounted for. The naked branches of the winter woods 

 afford exceptional opportunities for studies of this kind, which cannot 

 well be carried on except out of doors. Note the effect of the mode of 

 branching upon the general outline of the tree ; compare the direction and 

 mode of growth of the larger boughs with that of small twigs in the same 

 species, and see if there is any general correspondence between them ; note 

 the absence of fine spray on the boughs of large-leaved trees, and account 

 for it. Account for the flat sprays of trees like the elm, beech, hackberry, 

 etc. ; the irregular stumpy branches of the oak and walnut ; the stiff 

 straight twigs of the ash ; the zigzag switches of the black locust, Osage 

 orange, elm, and linden. Measure the twigs on various species, and see 

 if there is any relation between the length and thickness of branches. 

 Notice the different trend of the upper, middle, and lower boughs in most 

 trees, and account for it. Observe the mode of branching of as many 

 different species as possible of some of the great botanical groups of trees ; 

 the oaks, hickories, hawthorns, and pines, for instance, and notice whether 

 it is, as a general thing, uniform among the species of the same group, and 

 how it differs from that of other groups. 



