CHAPTER III 
STEMS 
21. Relation to other organs.—The stem is connected 
with the roots and bears the leaves. So constant a feature 
of the stem is leaf-bearing that the presence of leaves is one 
method of distinguishing underground stems from roots. 
Not merely do stems bear leaves, but they usually bear 
them in such a way as to expose them well to the air and 
the sunlight. Often stems branch, and in this way in- 
crease their power of producing and displaying leaves. It 
is evident that the stem, more than anything else, is the 
leaf-bearing organ; and in bearing leaves it must be also 
the channel of communication between them and the roots. 
So closely associated are stems and leaves that they are 
spoken of together as the shoot; and thus the whole body of 
the plant of ordinary experience is said to consist of shoot 
and root, the former usually exposed to the air (aerial), 
the latter usually exposed to the soil (subterranean). As 
any branch is merely a repetition of the stem from which it 
arises, so any branch with its leaves is a shoot, just as the 
whole stem system with its leaves is a shoot. 
22. External structure.—The ordinary stem is a jointed 
structure. While this is very evident in such stems as the 
corn-stalk and the cane (seen in fishing-rods), it is often 
made apparent only by the leaves, which appear at the 
joints or nodes (§ 8). The portions of the stem between the 
nodes— portions which do not bear leaves—are the internodes; 
hence a stem is a series of alternating nodes and internodes. 
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