322 



LUSSONS WITH PLANTS 



390o. Common ink will not answer foi' this purpose because it 

 "runs" when the root is wet, hut indelible ink, used for marking 

 linen or for drawing, should be used. It should also be said that 

 the roots of the common pumpkin and of the summer bush squashes 

 are too fibrous and branchy for this test. 



3906. It should be stated that the root does not grow at its 

 very tip, but chiefly in a narrow zone just back of the tip ; but 

 the determination of this point is rather too difficult for the be- 

 ginner, and, moreover, it is foreign to the purpose of this lesson. 



391. Now let us make a similar experiment 

 with the stem or stalk. Mark a young stem, as 



at A in Fig. 341; but the 

 next day we shall find that 

 these marks are farther 

 apart than when we made 

 them (B, Fig. 341). The 

 marks have all raised them- 

 selves above the ground as 

 the plant has grown. The 

 stem, therefore, has grown 

 throughout its length rather 

 than from the end. The 

 stem usually grows most 

 rapidly, at any given time, 

 in the upper or younger 

 portion ; but the part soon 



The marking of the stem and the ^e^cheS the limit of itS 

 spreading apart or the marks. 



growth and becomes sta- 

 tionary, and the growth continues beyond it. (See 

 "Suggestions," p. 48.) 



PIG. 341. B 



