76 Principles of Plant Culture. 
other end, and becomes, at least for a time, the main axis 
or stem of the plant. 
115. The Stem 
is, generally speaking, 
the part of the plant 
that supports the 
leaves. In exceptional 
cases, as in the potato 
(Fig. 32) and quack 
“ grass, a part of the 
~Agstem grows beneath the 
e ground (underground 
; stems), when the leaves 
usually do not develop; 
and in a few plants, as 
fy- ® . 
i “\\ \ ~ in some cacti, the stem 
AA. ; performs the whole of- 
fice of leaves. The stem 
Fro. 32. Potato plant. U.st., underground stems. may be strong enough 
R. Roots. The tubers are the thickened distal t peat 
ends (116) of the underground stems. Much re- oO suppor 1s own 
duced. (After Frank and Tschirch). weight, as in trees and 
shrubs, or it may depend upon other objects for its support 
as in vines. 
116. Nodes and Internodes. Unlike the root, the stem 
is developed in successive sections, comparable in part to 
the stories of a building. Each section or story consists of 
one or more leaves, attached to the distal* end of a portion 
of the stem. The part of the stem to which the leaf or 
leaves is attached is called a node and the part below the 
* Distal means farthest from the point of origin, i.e., the point at which growth 
started. It is opposed to proximal, which means nearest the point of origin. 
