18 



THE STEM 



24. A thickened stem, bearing buds 

 or "eyes." Potato. 



EEVIEW. What is the stem 

 system? What does the stem do? 

 How long may the stem persist? 

 What is meant by the habit of a 

 plant? Name some kinds of habit. 

 What are so-called stemless plants? 

 What is the crown ? What becomes 

 of the tops of stemless plants ? 

 What are erect, trailing, decum- 

 bent, ascending, climbing stems? 

 What are excurrent trunks? Deli- 

 quescent? What is a simple stem? 

 What are strict stems ? What 

 are subterranean 

 stems ? How are 

 What is the differ- 



stems distinguished from roots? 



ence in mode of growth between stems and roots? 



NOTE. The pupil should make marks with water- 

 proof ink (as Higgins' ink or indelible marking ink) 

 on any soft growing stems as geranium, fuchsia, 

 grass, the twigs of trees. Note that the separation of 

 the marks is most evident on the youngest shoots. 



The pupil should observe the fact that a stem of 

 a plant has wonderful strength. Compare the pro- 

 portionate height, diameter and weight of a grass stem 

 with those of the slen- 

 derest tower or steeple. 

 Which has the greater 

 strength? Which the 

 greater height ? Which 

 will withstand the most 

 wind ? Note that the 

 grass stem will regain its 

 position even if its top 

 is bent to the ground. 

 Split a corn stalk and 

 observe how the joints 

 are tied together and 

 braced with fibers. Note 

 how plants are weight- 

 ed down after a heavy 

 rain. 



26. The result. 



