CHAPTER VI 
STEMS 
/ 62. What the Stem is. — The work of taking in the raw 
materials which the plant makes into its own food is done 
mainly by the roots and the leaves. These raw materials 
are taken from earth, from water, and from the air (see 
Chapter x11). The stem is that part or organ of the plant 
which serves to bring roots and leaves into communica- 
tion with each other. In most flowering plants the stem 
also serves the important purpose of lifting the leaves 
up into the sunlight where alone they can best do their 
special work. 
The student has already, in Chapter 11, learned some- 
thing of the development of the stem and the seedling; 
he has now to study the external appearance and internal 
structure of the mature stem. Much in regard to this 
form and structure can conveniently be learned from the 
examination of twigs and branches of our common forest 
trees in their winter condition. 
63. The Horse-Chestnut Twig.!— Procure a twig of horse-chestnut 
eighteen inches or more in length. Make a careful sketch of it, 
trying to bring out the following points. 
(1) The general character of the bark. 
1 Where the buckeye is more readily obtained it will do very well. Hickory 
twigs answer the same purpose, and the latter is a more typical form, having 
alternate buds. The magnolia or the tulip tree will do. The student should 
(sooner or later) examine at least one opposite- and one alternate-leaved twig. 
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