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 codperation 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, 
ete.; 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. 
