CHAPTER IV 
SHOOTS 
40. General characters. The term shoot is used to include 
both stem and leaves. Among the lower plants, such as 
the algae and toadstools, there is no distinct stem and leaf. 
In such plants the working body is spoken of as the thallus, 
which does the work done by both stem and leaf in the 
higher plants. These two kinds of work are separated in 
the higher plants, and the shoot is differentiated into stem 
and leaves. 
41. Life-relation. In seeking to discover the essential 
life-relation of the stem, it is evident that it is not neces- 
sarily a light-relation, as in the case of the foliage leaf, 
for many stems are subterranean. Also, in general, the 
stem is not an expanded organ, as is the ordinary foli- 
age leaf. This indicates that whatever may be its essential 
life-relation it has little to do with exposure of surface. 
It becomes plain that the stem is the great leaf-bearing 
organ, and that its life-relation is a leaf-relation. Often 
stems branch, and this increases their power of producing 
leaves. 
In classifying stems, therefore, it seems natural to use 
the kind of leaves they bear. From this standpoint there 
are three prominent kinds of stems : (1) those bearing foli- 
age leaves ; (2) those bearing scaly leaves ; and (3) those 
bearing floral leaves. There are some peculiar forms of 
stems which do not bear leaves of any kind, but they need 
not be included in this general view. 
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