STEM VS. ROOT 



17 



each, with waterproof ink mark spaces exactly one-quarter 

 inch apart. Keep the plantlets moist for a clay or two, and 

 it will be found that on the stem some or all of the marks 

 are more than one-quarter inch apart; on the root the 

 marks have not separated. The root has grown 

 beyond the last apical mark. (Figs. 25, 26.) 



Review. — What is the stem system? What does 

 the stem do? How long may the stem persist? Whal 

 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, decumbent, ascending, 

 climbing stems? What are excurrent trunks? Deli- 

 quescent? What is a simple stem? What are strict 

 stems? What are subterranean stems? How are sterna 

 distinguished from 

 roots? What is the dif- 

 ference in mode of 

 growth between stems 

 and roots? 



Note. — T h e pupil 

 s h o u 1 d make marks 

 with waterproof 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 evi- 

 dent on the youngest 

 shoots. 



The pupil should observe the fact that a stem of a plant has wonder- 

 ful strength. Compare the proportionate height, diameter ami weight 

 of a grass stem with those of the slenderest tower or steeple. Which 

 has the greater Strength? Which the greater height'.' Which will with- 

 stand the most wind? Note that the grass stem will regain its position 

 even if its top is bent to the ground. Split a cornstalk and observe how 

 the joints are tied together and braced with fibers. Note how plants 

 are weighted down after a heavy rain. 

 B 



25,. The markiiiK of 

 the stem and root. 



20. The result. 



