CHAPTER III. 

 THE BOOT. 



I. From observations made upon the seedlings mentioned in 

 the preceding chapter, it is seen that each of them is made up of 

 distinct parts, namely, root, stem, and leaves. These parts are 

 usually present in all the common flowering plants, and it is 

 needful to examine them separately and in detail. 



Primary and Secondary Boots It was noticed, when deal- 

 ing with the bean seedling, that its two ends always grow in 

 opposite directions ; the plantlet can be considered as an elon- 

 gated axis, one end of which bears the leaves and invariably 

 comes above ground, while the opposite end never bears leaves, 

 and persistently follows the plumb-line downwards. The de- 

 scending part is known as the root. As will be pointed out 

 later, all roots do not behave in this manner, and it is to be 

 specially noted that many of the underground parts of plants 

 are not roots ; the exceptions, however, may be left for future 

 consideration. 



The first or primary root which the bean plant possesses is 

 merely an extension of the radicle of the embryo which exists 

 within the seed. Soon after making its exit from the seed, it 

 takes a downward course, and elongates by growth taking place 

 near its tip. 



Ex. 16. —Germinate a broad bean on damp flannel. When the primary root 

 is about \ of an inch long, make small dots upon it about tV of an inch apart, 

 with a pen or fine brush dipped in Indian ink. Wrap the bean in damp cotton 

 wool, allowing the marked root to be free, and place it in the bottom of a 

 glass funnel with a narrow stem, so that the marked root projects down the 

 latter. Cover over the funnel with a piece of gl.-iss or cardboard to prevent 



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